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1038
Section 11
Cranial Base Surgery
Translabyrinthine Approach
When hearing is absent and greater petrosal exposure
is required, a translabyrinthine approach can be com-
bined with an anterior petrosal approach. This approach
is described in detail in Chapter 124.
Transcochlear Approach and Total Petrosectomy
The transcochlear approach is an anterior extension of
the translabyrinthine approach that is used to gain
additional exposure to the petrous apex and petroclival
region. This approach requires posterior transposition
of the facial nerve from the meatal segment to the sty-
lomastoid foramen. The facial nerve remains in the
posterior aspect of the surgical fi eld as tumor dissection
proceeds anteriorly and medially over the clival
region.
In addition to the exposure provided by the trans-
labyrinthine approach, the external auditory canal is
transected at the bony-cartilaginous canal and oversewn
in two layers to achieve a watertight seal. The facial
recess is opened and the facial nerve is skeletonized
along the tympanic and mastoid segements, down to
the stylomastoid foramen. The incus is removed through
the mastoid antrum. The skin of the ear canal is then
removed in continuity with the tympanic membrane
and malleus, and the canal wall is lowered to the level
of the facial nerve in the mastoid segment. Both the
chorda tympani and GSPN are sectioned at their origins
from the facial nerve to allow posterior transposition of
the facial nerve out of the fallopian canal.
Next, the cochlea is drilled out and bone between
the basal turn of the cochlea and the horizontal segment
of the petrous ICA is removed, including the carotid
ridge, to completely expose the jugular bulb and pars
nervosa. Cranial nerves IX, X, and XI will be within the
fi eld of dissection as they exit the jugular foramen and
are at risk for injury.
To access lesions of the clivus, anteromedial brain
stem, infratemporal fossa, and posterior nasopharynx,
this approach is combined with a middle fossa approach.
The surgical steps are modifi ed accordingly. After tran-
secting and oversewing the external auditory canal, the
subtemporal sphenoid bone is removed up to the
foramen ovale with a rongeur to completely expose
the mandibular nerve (V3) (Fig. 102-36). The petrous
carotid is completely unroofed from the precavernous
segment to the upper cervical segment while leaving
the artery sheathed in periosteum (Fig. 102-37). As
mentioned earlier, the middle meningeal artery and
GSPN are transected, and the cartilaginous eustachian
tube is cauterized, packed with fat, and sutured closed.
At this point the cochlea and medial petrous bone are
removed through the posterior approach to expose the
jugular bulb deep to the facial nerve, including the pars
nervosa. Skeletonization of the facial nerve is then com-
pleted anteriorly via the middle fossa approach. The
facial nerve is completely decompressed and mobilized
posteriorly and inferiorly to provide wide surgical expo-
sure for tumor removal. When the facial nerve is mobi-
lized in this manner, the proximal and distal blood
Zygomatic
osteotomy
V3
Middle
meningeal
a.
GSPN
VII
Figure 102-36. Total petrosectomy: radical mastoidectomy with
removal of the subtemporal bone to expose V3. The middle menin-
geal artery is divided. GSPN, greater superfi cial petrosal nerve.
(Redrawn from Cass SP, Sekhar LN, Pomeranz S, et al: Excision of petroclival
tumors by a total petrosectomy approach. Am J Otol 15:474-484, 1994.)
VII
Stapes
Eustachian
tube
Petrous ICA
Figure 102-37. Total petrosectomy: exposure of the petrous inter-
nal carotid artery (ICA). (Redrawn from Cass SP, Sekhar LN, Pomeranz
S, et al: Excision of petroclival tumors by a total petrosectomy approach. Am
J Otol 15:474-484, 1994.)
supply to the nerve from the intracranial vessels and
stylomastoid artery, respectively, is preserved.
Once the inferior fi brocartilaginous ring surround-
ing the upper cervical carotid artery is divided, the
carotid artery can be mobilized forward without tension
and held in place with a suture along the periosteum
of the carotid canal. The medial petrous apex clival
bone can then be removed to the midline to provide
wide exposure with direct views of the midclivus, ante-
rior brain stem, and basilar artery (Fig. 102-38).
A rarely used variant of the transcochlear approach
is the transotic approach, in which the facial nerve is

Chapter 102
Petrosal Approaches 1039
not transposed and tumor resection is performed in
front of and behind the facial nerve within the fallopian
canal.
Wound closure for the posterior petrosal approaches
involves meticulous inspection and obliteration of
potential CSF fi stulas. Bone wax is used to seal off any
remaining air cells within the temporal bone. The
middle ear and mastoid cavity are packed with autolo-
gous muscle or fat grafts. The wound is closed in layers,
including reapposition of the temporalis fl ap to its
superior cuff and application of a pressure dressing and
a subgaleal drain. In addition, when the facial nerve is
fully exposed, as in a transcochlear or total petrosec-
tomy approach, covering the nerve with Silastic at the
time of closure helps aid in identifi cation of the nerve
if future surgery is warranted. The extensive operative
time needed for the combined approaches and total
petrosectomy often necessitates staged surgery 1 week
apart.
Expanded Endoscopic Nasal Approach
Kassam and coauthors at the University of Pittsburgh
have published landmark papers on the use of endo-
scopic expanded endonasal approaches for skull base
surgery.5,15 All patients for endoscopic skull base surgery
undergo preoperative imaging, including high-resolu-
tion CT angiography and sometimes additional con-
trast-enhanced MRI of the brain, depending on the
tumor type and location. Patients are positioned supine
with the head in neutral position and secured with
three-point fi xation in a Mayfi eld head frame. Intraop-
erative frameless stereotactic image guidance is used in
every case. When lesions involve or abut critical neuro-
vascular structures, we recommend monitoring the
patient intraoperatively with somatosensory evoked
potentials, brain stem evoked responses, and electromy-
ography as indicated. The nasal cavities are packed with
oxymetazoline-soaked pledgets, and a third- or fourth-
generation cephalosporin is administered periopera-
tively for prophylaxis. We recommend a team surgery
approach that includes an otolaryngologist and neuro-
surgeon, with both nares used simultaneously for
surgery. The use of an endoscope holder by an inde-
pendent surgeon prohibits dynamic intraoperative
examination and adaptation.
Surgery begins with the development of a transna-
sal corridor, which involves rigid nasal endoscopy with
a 0-degree endoscope, oftentimes with an irrigating
sheath. The right middle turbinate is lateralized. Fre-
quently, the inferior aspect of the right middle turbi-
nate is resected with curved scissors to accommodate
the instruments and the endoscope in the right nasal
cavity. Suction electrocautery is then used to obtain
hemostasis. At this time, if the surgical defect is antici-
pated to be large or extend intracranially, a posterolat-
erally pedicled vascularized septonasal mucosa fl ap
based on the posterior nasal branch of the sphenopala-
tine artery is raised via electrocautery.16 The anterior
extent of the fl ap should come to the caudal septum.
The width of the fl ap should be maximized by careful
dissection of the superior limit and the inferior exten-
sion along the fl oor of the nasal cavity. The fl ap is then
displaced into the maxillary sinus if an antrostomy is
indicated or rotated into the nasopharynx to protect it
from trauma during the remainder of the procedure.
A 1- to 2-cm posterior septectomy is performed just
anterior to the rostrum of the sphenoid to allow bilat-
eral dissection without contamination of the endoscope.
After cauterization of the underlying mucosa, large
pituitary forceps are used to remove the rostrum and
thereby enter the sphenoid sinus. Wide bilateral sphe-
noidotomies are created with a Kerrison rongeur and
extended laterally and inferiorly to the level of the
medial pterygoid plates (pterygoid wedge, where the
vidian canal is located). If a septal fl ap is not used,
the posterior septal artery is coagulated and transected
as it crosses the inferior aspect of the rostrum to facili-
tate removal of this portion of the rostrum and the fl oor
of the sphenoid sinus.5,15 Within the wide sphenoidoto-
mies, the optic nerve canals, carotid arteries, lateral
optic-carotid recesses, planum sphenoidale, and clival
indentation or recess are identifi ed. Often the sphe-
noid sinus is asymmetrically pneumatized and as a result
one or both of the intersinus septa lead directly back to
the carotid artery. Therefore, these septa should be
removed with biting instruments and not pulled off.
Occasionally, the optic nerve and carotid artery may be
dehiscent within the sphenoid sinus. Finally, the large
sphenoidotomy provides room for surgical access and
maneuverability.
After the transnasal corridor is established, various
approaches can be taken to the skull base. To approach
the medial petrous apex, the basopharyngeal fascia is
stripped away from the superior nasopharynx, and the
sphenoid fl oor is then drilled until it is fl ush with the
clival recess. As mentioned earlier, if not elevated in a
fl ap, the sphenopalatine and posterior nasal arteries are
isolated and ligated. A posterior maxillary antrostomy
Tumor
Midbrain
Tentorium
VIII
Medulla
Geniculate
ganglion
IX, X
Vertebral
a.
VI
Pons
Figure 102-38. Total petrosectomy: exposure of the clivus and
tumor after mobilization of the facial nerve and carotid artery. ICA,
internal carotid artery; JB, jugular bulb. (Redrawn from Cass SP, Sekhar
LN, Pomeranz S, et al: Excision of petroclival tumors by a total petrosectomy
approach. Am J Otol 15:474-484, 1994.)

1040
Section 11
Cranial Base Surgery
is performed to identify the key surgical landmark, the
medial pterygoid plate. This plate is drilled for about
1 cm along the vidian artery, perpendicular to the
clivus, to the anterior genu of the internal carotid
artery. The bone is drilled eggshell thin with a coarse
3-mm diamond burr, and the internal carotid artery is
exposed. The bone lateral to the internal carotid artery
is removed to allow lateral translocation of the vessel
without compressing it. Once the internal carotid artery
is moved laterally, the underlying petrous apex can be
directly accessed and the approach can be extended to
the medial anterior margin of the IAC. This approach
is ideal for extradural lesions such as cholesterol granu-
lomas and cholesteatomas.
The expanded endonasal approach can also be
used for direct access to the medial aspect of the petro-
clival junction, previously only accessed by conventional
lateral skull base approaches, which require a signifi -
cant degree of petrous bone resection.15 The vidian
canal is identifi ed at the level of the medial pterygoid
plate and followed to its origin from the anterior genu
of the internal carotid artery. The bone over the hori-
zontal segment, genu, and parasellar carotid protuber-
ance can be removed with a combination of high-speed
drills with extended burr shafts and fi ne 1-mm Kerrison
rongeurs. The medial portion of the clivus at the pet-
roclival junction is drilled to expose the dura and
venous plexus. Dorello’s canal can be followed supero-
laterally to the cavernous sinus. The cavernous sinus
represents the superior boundary of this exposure and
the middle fossa represents the lateral boundary.
Venous bleeding from the cavernous sinus and basilar
venous plexus is controlled with Avitene microfi brillar
collagen packing (Davol, Inc., Cranston, RI). The dura
medial to the posterior margin of the cavernous sinus
can be opened to provide access to the pontine cistern.
This approach has been used for chondrosarcomas,
chordomas, and sinonasal lesions of the petroclival
space, such as meningiomas, to provide a direct route
to the tumor without signifi cant neurovascular
manipulation.5
Expanded endoscopic nasal surgery can be further
extended to the quadrangular space.15 The borders of
the quadrangular space include the middle fossa later-
ally, the horizontal petrous internal carotid artery infe-
riorly, and the abducens nerve superiorly.5 The approach
to the quadrangular space involves isolating the maxil-
lary division of the trigeminal nerve, V2, through a wide
maxillary antrostomy. After the vidian canal is followed
to the anterior genu of the internal carotid artery, V2
is isolated and followed superiorly to the foramen
rotundum. Care should be taken during bone removal
because the space between V2 and the vidian canal
narrows posteriorly. The bone over the horizontal
portion of the internal carotid artery is removed, and
dissection continues superiorly to the lateral portion of
the cavernous sinus, where V2 disappears into the dura
mater. The dura is opened in a medial-to-lateral direc-
tion from the genu of the internal carotid artery toward
V2. This approach allows access into Meckel’s cave, the
petrous bone, and the posterior fossa for tumor resec-
tion. The use of angled telescopes enhances the surgi-
cal view around corners and in tight areas. By remaining
below the abducens nerve and lateral to the internal
carotid artery throughout the procedure, the superior
portion of the cavernous sinus, where cranial nerves III,
IV, V1, and VI are located, can be avoided, thus reduc-
ing the risk for postoperative cranial nerve palsy.
Finally, when tumors invade and thrombose the
superior aspect of the cavernous sinus, this region can
be accessed via a dural opening above the quadrangular
space in a medial-to-lateral direction over the superior
lateral portion of the cavernous sinus.15 Initially, bleed-
ing is reduced secondary to tumor-induced thrombosis.
The medial margin of the internal carotid artery is
identifi ed by opening the sella. With the internal carotid
artery protected with a dissector, the tumor can be
safely stripped away from the cranial nerves. The inci-
dence of cranial neuropathy is signifi cantly increased
when the tumor is adherent to the cranial nerves and
when aggressive packing of postresection venous bleed-
ing from the inferior petrosal sinus is necessary. There-
fore, this approach should be reserved for tumors that
are refractory to medical or radiosurgical management
or for tumors with preexisting cranial nerve defi cits.
Another advantage of the endonasal route is the ability
to follow tumor into the pterygopalatine and infratem-
poral fossae with angled telescopes. Endonasal
approaches have been successful in removing tumor as
far lateral as the masticator space and pterygoid
musculature.
Reconstruction
For open lateral approaches, reconstruction begins
with primary dural repair or a dural graft of fascia lata
or temporalis fascia, or both repair and a graft, for
residual defects or extra support. Abdominal fat is typi-
cally used to obliterate the surgically created mastoid or
petrous cavities. The bone graft removed at the start of
the procedure is reapplied with miniplates and screws.
The temporalis muscle is reattached to the superior
cuff on the skull so that it reassumes its anatomic posi-
tion. The skin is closed in dermal and epidermal layers,
and a pressure dressing is applied. Depending on the
fi eld of dissection, a suction drain may be applied
between the musculature and dermal layers.
For the expanded endonasal approach, reconstruc-
tion varies from simple packing of the sphenoid defect
with duricel or autologous fat grafts for extradural
lesions to more involved layered packing with AlloDerm
(LifeCell Corporation, Branchburg, NJ) inlay or onlay
grafts for repair of the resulting dural defect and sub-
sequent packing of the bony defect with autologous fat,
DuraGen (Integra Life Sciences Corporation, Plains-
boro, NJ), and a vascularized septal mucosa fl ap.5,15 A
temporary balloon catheter positioned in the nasophar-
ynx is fi lled with saline to reinforce the packing and
prevent migration of the grafts. When the cavernous
sinus is involved, packing with Avitene for hemostasis
plus placement of autograft composed of abdominal or
thigh fat is required to protect the exposed internal
carotid artery.

Chapter 102
Petrosal Approaches 1041
POSTOPERATIVE CARE AND
COMPLICATIONS
Petrosal approaches expose larger portions of the skull
base and thus place the patient at risk for signifi cant
complications, including CSF leak, wound infection,
meningitis, cranial neuropathy, cerebral edema, pneu-
mocephalus, seizures, temporal lobe hemorrhage,
stroke, and pulmonary embolism.
Cerebrospinal Fluid Leak
The key to avoiding postoperative CSF leak is preven-
tion intraoperatively the time of surgery through metic-
ulous repair of dural defects, dural grafting, and
restrictions in postoperative activities, such as straining
with bowel movements, nose blowing, and weight
bearing. CSF usually leaks through the eustachian tube
or though the incision. Because primary repair of the
surgical wound is not always possible with the more
extensive petrosal approaches, closure of the dural
defects with free or vascularized grafts and packing of
the dead space and the eustachian tube with fat and
connective tissue, respectively, are essential. For hearing-
preserving posterior petrosal approaches, such as the
retrolabyrinthine and partial labyrinthine approaches,
the eustachian tube and middle ear are not packed.
Instead, only the mastoid antrum and cavity are loosely
packed with an abdominal fat graft to minimize the risk
of postoperative conductive hearing loss from adhe-
sions involving the ossicular chain. Some postoperative
conductive hearing loss is expected for 4 to 6 weeks as
a result of hemotympanum. The transcochlear and
total petrosectomy approaches require transection and
blind sac closure of the external auditory canal and
eustachian tube.
As mentioned, the surgical cavities are packed with
fat and muscle grafts to limit the risk of CSF leaking
through the incision. Additional measures to minimize
this risk include oversewing the incision with nonab-
sorbable suture material, applying a compressive
mastoid dressing for up to 72 hours, bed rest with the
head elevated 30 to 45 degrees, and occasionally, lumbar
drainage. Planning the incisions and dissection preop-
eratively also helps reduce the risk of leaks. The skin
and muscle incisions should be stair-stepped. For larger
defects, temporalis muscle fl aps can be used to line the
defects. When all the aforementioned measures have
been attempted and CSF leakage persists, surgical re-
exploration should be considered in an otherwise stable
patient.
The risk of CSF leakage is increased in expanded
endonasal approaches because of limitations with dural
closure. The size of the defect, location of the defect,
and experience of the surgeon are the most important
factors in preventing postoperative leaks. Endoscopic
repairs depend on the ability of the brain to settle over
the repair and hold the tissues in place over the defect.
Thus, excessive lumbar drainage will actually increase
the likelihood of repair failure. A multilayered closure
is the best way to seal endoscopic approaches. Typically,
AlloDerm inlay or onlay grafts (or both) are used to
cover the dural defect and are fi xed in place with tissue
adhesives such as Dura Seal (Confl uent Surgical, Inc.,
Waltham, MA) and Tisseel VH (Baxter, Deerfi eld, IL).
Abdominal fat grafts are used to fi ll the extradural sur-
gical defect, and frequently a vascularized nasal septal
fl ap with tissue adhesive is used to cover the surface. To
minimize postoperative leaks, a Foley balloon catheter
can be left in place for 5 to 7 days. Alternatively, the
nasal cavity may be packed with Merocel sponges to
secure the fl aps in place, with removal after 3 to 5 days.
Systemic antibiotics should be administered for the
duration that the packing remains in place. If a CSF
leak occurs despite these measures, passive lumbar
drainage and bed rest are often effective in controlling
the leak, and in refractory cases, the defect can typically
be repaired endoscopically.
Infections
The majority of infectious complications can be pre-
vented with appropriate perioperative antibiotics, sterile
surgical technique, and meticulous wound closure.
Localized wound infections, pneumonia, and urinary
tract infections are risks associated with any major surgi-
cal procedure, and standard postoperative care should
be undertaken to prevent these problems, including
postoperative incentive spirometry for pulmonary toilet,
prompt removal of indwelling lines and catheters, and
early ambulation. Specifi cally for petrosal approaches,
the risk of meningitis and epidural abscess is real, and
they can be catastrophic. Perioperative antibiotics
should be administered for at least 24 hours after
surgery and longer if nasal packing was placed. Postop-
erative fevers or elevated white blood cell counts should
be investigated by blood culture, complete blood count,
urinalysis, sputum culture, chest radiography, head CT,
and lumbar puncture if clinically warranted. Empirical
antibiotics with good CSF penetration should be initi-
ated according to Gram stain results or evidence of
clinical deterioration.
Cranial Neuropathies and Temporal
Lobe Injury
Cranial neuropathies and temporal lobe injuries,
including seizure, hemorrhage, stroke, and functional
atrophy, are the result of traction injury to the brain
during attempts to increase exposure during surgery.
Using a combination of anterior and posterior petrosal
approaches for larger and anteriorly located tumors
within the skull base and lowering the level of the cra-
niotomy to the fl oor of the middle cranial fossa in
anterior petrosal approaches help limit such injuries.
With more midline lesions in the petroclival region,
endoscopic nasal approaches offer the advantage of
direct access to the tumor with less risk for postopera-
tive cranial neuropathy.
If the lower cranial nerves are at risk because of the
size or location of the tumor, preoperative or early
postoperative assessment of speech and swallowing is
essential to limit aspiration and expedite recovery and

1042
Section 11
Cranial Base Surgery
rehabilitation. If the lower cranial nerves are compro-
mised at the time of surgery, the patient should be
treated promptly by tracheostomy, and safe enteral
access should be obtained via a nasogastric or gastros-
tomy tube. If injury is anticipated preoperatively, con-
current medialization thyroplasty may be performed to
prevent postoperative voice and swallowing diffi culties.
When the GSPN is sacrifi ced, postoperative dry eye syn-
drome should be anticipated and managed with aggres-
sive eye protection and lubrication. If injury occurs to
the main trunk of the facial nerve, eye protection with
a moisture chamber, lubrication, and early surgical
rehabilitation with an upper eyelid gold weight or pal-
pebral spring should be considered.
Postoperative seizure activity should be controlled
with neuroleptic medications, and neurology should be
promptly consulted for management. For all anterior
petrosal approaches in which the temporal lobe is
retracted for prolonged periods, prophylactic anticon-
vulsants such as phenytoin are indicated.
Pneumocephalus and Cerebral Edema
Pneumocephalus and cerebral edema tend to be early
complications that result in focal neurologic defi cits
and progressive deterioration in mental status, although
pneumocephalus can also occur as a late complication
secondary to violation of the dural closure with Valsalva
maneuvers.
Mild asymptomatic pneumocephalus is commonly
seen on early postoperative imaging and is a result of
the surgical exposure. It usually resolves within 1 to 2
weeks. However, large or increasing pneumocephalus
(tension pneumocephalus), particularly in the setting
of mental status changes, should be managed by prompt
surgical decompression because the expanding air will
result in brain compression and potentially brain her-
niation. Sources of pneumocephalus are identical to
those for CSF leaks and include the nasal cavity, the
eustachian tube, and the surgical incision. Imaging
studies can be used to localize the defect. Although
prevention with meticulous wound closure is essential,
avoiding disruption of the repair in the postoperative
period is also paramount in preventing pneumocepha-
lus. Excessive lumbar spinal drainage may draw air into
the cranial cavity through the nasal cavity, and excessive
positive pressure ventilation may displace grafts used to
repair nasal defects resulting from endoscopic surgery.
Care should therefore be exercised when managing
lumbar drains and tracheostomy tubes after surgery.
Cerebral edema can also lead to brain herniation
and mortality if not recognized and treated promptly.
We routinely perform CT or MRI of the head within 24
hours after surgery to assess for the presence and degree
of edema. In the event that clinically signifi cant edema
occurs, treatment includes osmotic diuresis with man-
nitol, systemic steroids, and hyperventilation to reduce
Pco2. An extraventricular drain may be placed at the
bedside to decompress the brain and monitor intracra-
nial pressure. If the cerebral edema is refractory to
these measures, the inferior temporal gyrus may have
to be partially resected.
Deep Venous Thrombosis and
Pulmonary Embolism
Deep venous thrombosis and pulmonary embolism are
postoperative complications with high morbidity and
mortality that are typically preventable. Prolonged
surgery and postoperative immobility drastically increase
the risk for thrombotic events. The use of pneumatic
compression stockings in the postoperative period dra-
matically reduces the incidence of such events. Early
postoperative ambulation and physical therapy are also
helpful. The risk for thromboembolic events is increased
in patients with meningiomas and paragangliomas.
Tachycardia and tachypnea are often the fi rst indi-
cators of pulmonary embolism and thus should be thor-
oughly evaluated in a postoperative patient. Once
hypoxia, shortness of breath, chest pain, hypotension,
or syncope develop, the prognosis is much poorer
because they signify a larger, more hemodynamically
compromising clot. Immediate evaluation with a con-
trast-enhanced spiral CT scan of the chest and interven-
tion are warranted, including thrombectomy, Greenfi eld
fi lter placement in the inferior vena cava, and in some
cases, thrombolytic therapy. Anticoagulation is not rou-
tinely used in intracranial surgery because of the risk
for intracranial hemorrhage.
PEARLS
• Open petrosal approaches are useful for petroclival
lesions within the middle and posterior cranial
fossae above the lower third of the clivus. Lower
clival tumor extension will require a transcondylar
approach.
• Exposure of the central clival depression requires a
transcochlear, total petrosectomy, or endonasal
approach.
• The petrous carotid artery is the central landmark
for anterior petrosal approaches; exposure and
isolation of this artery are essential for vascular
control.
• In the expanded endonasal approach, the vidian
canal is used as a landmark to locate the petrous
carotid artery.
• The asymmetrical intrasinus septum in the sphenoid
sinus often leads to the vertical petrous carotid
artery, and careful removal is necessary to prevent
injury to the carotid artery.
PITFALLS
• Surgical dissection should proceed with caution
because the carotid artery and optic nerve may be
dehiscent on the lateral wall of the sphenoid sinus.
• Tumor extending into the posterior fossa is not
accessible through an anterior petrosal approach
alone and often necessitates combined anterior and
posterior petrosal exposure.

Chapter 102
Petrosal Approaches 1043
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14. Rhoton AL Jr: The temporal bone and transtemporal approaches.
Neurosurgery 47(Suppl):S211-S265, 2000.
15. Kassam A, Thomas AJ, Snyderman C, et al: Fully endoscopic
expanded endonasal approach treating skull base lesions in pedi-
atric patients. J Neurosurg 106:75-86, 2007.
16. Hadad G, Bassagasteguy L, Carrau RL, et al: A novel reconstruc-
tive technique after endoscopic expanded endonasal approaches:
Vascular pedicle nasoseptal fl ap. Laryngoscope 116:1882-1886,
2006.

Chapter 103
Endonasal Approach to the Sella and
Parasellar Areas
Carl H. Snyderman, Ricardo L. Carrau, and Amin B. Kassam
The evolution of cranial base surgery over the last 2
decades is best exemplifi ed by the evolution of surgical
approaches for pituitary tumors. There has been a tran-
sition from an open microscopic approach to a “mini-
mally invasive” endoscopic approach. For many years, a
sublabial, transseptal microscopic approach was the
standard of care. It entailed a sublabial mucosal inci-
sion with dissection of the nasal septum in a submuco-
perichondrial/subperiosteal plane. The septal cartilage
was displaced to the side and the vomer was removed.
After removal of the sphenoid rostrum, a self-retaining
retractor was placed. The main limitations of this
approach were the narrow nasal corridor and poor visu-
alization. Postoperative discomfort was signifi cant.
The next stage in pituitary surgery was a transnasal,
transseptal approach. The transseptal approach avoided
the morbidity of the sublabial incision but provided a
smaller surgical corridor. It entailed a hemitransfi xion
incision in the septal mucosa with disarticulation of the
cartilaginous septum and creation of a submucoperi-
chondrial/subperiosteal tunnel. The remainder of the
dissection was the same as for the sublabial approach,
with placement of a self-retaining retractor in one
nostril. The major defi ciency of this approach was a
narrow surgical corridor with limited visualization and
room for instrumentation.
After introduction of the nasal endoscope in the
1980s, a completely endonasal endoscopic approach to
the sphenoid sinus and sella was developed.1 Refi ne-
ments included the binarial approach, the development
of new instrumentation for endonasal skull base surgery,
the concept of a modular approach to the skull base
with extensions from the sella in the sagittal and coronal
planes, and the introduction of septal mucosal fl aps for
dural reconstruction.2-4 Advantages of the endonasal
endoscopic approach include less soft tissue morbidity
and postoperative pain than with the sublabial approach,
improved visualization, and increased access.
The endonasal approach to the sella is the starting
point for many endonasal surgeries on the ventral skull
base. A midline approach to the sphenoid can also be
used for other sphenoid sinus pathology such as chronic
sinusitis, mucoceles, and meningoceles, especially when
normal sinus anatomy is obscured by pathology or pre-
vious surgery. A midline approach provides a reliable
means of accessing the sphenoid contents and mini-
mizes the risk of inadvertent injury to lateral structures
(optic nerve, internal carotid artery [ICA]).
ANATOMY
The sphenoid sinus is geometrically shaped like a cube.
The rostrum of the anterior wall is shaped like the
prow of a ship and articulates with the vomer bone of
the septum in the midline (Fig. 103-1). The sphenoid
ostium is located at the superolateral corner of the sinus
behind the attachment of the superior turbinate. The
roof of the sphenoid sinus is the planum sphenoidale
and is bounded by the cribriform plates and the fovea
ethmoidalis anteriorly. The posterior wall of the sphe-
noid sinus is characterized by the bulge of the sella
superiorly and the depression of the clival recess infe-
riorly (Fig. 103-2). The brain stem and vertebrobasilar
arteries are situated deep to this bone. The tubercular
strut is a thick ridge of bone overlying the superior
intercavernous sinus at the junction of the sella and
planum sphenoidale. The degree of pneumatization of
the sphenoid sinus is variable and can be categorized
as presellar, sellar, or postsellar pneumatization
patterns.
1045

1046
Section 11
Cranial Base Surgery
less apparent but represents a “danger zone” where the
ICA courses medially toward the sella. The pneumatiza-
tion of the sphenoid sinus may extend laterally into the
base of the pterygoid plates. When this occurs, the
pneumatized sinus extends between the pterygoid canal
(vidian artery and nerve) inferiorly and the foramen
rotundum (second division of the trigeminal nerve)
superiorly.
Anatomic variations of the sphenoid are common
and may increase the risk for inadvertent injury to struc-
tures bordering the sphenoid sinus. The sphenoid sinus
often contains multiple septations. Lateral septations
always attach to the carotid canal (see Fig. 103-2). The
prominence of the carotid canal is quite variable and it
may be dehiscent in approximately 10% of patients
(Fig. 103-5). Tortuosity of the carotid arteries is pro-
Sphenoid
crest
Aperture of
sphenoid sinus
Superior
orbital fissure
Pterygoid
canal
Lateral
plate
Medial
plate
Pterygoid
process
Foramen
rotundum
Orbital
surface
Figure 103-1. Anterior view of the sphenoid bone with
bony landmarks identifi ed. The extent of the sphenoid-
otomy is outlined; it extends between the foramen rotun-
dum and pterygoid canal and includes the lateral
recess.
PS
Sella
CR
ICA
Figure 103-2. Bony landmarks in the sphenoid sinus include the
planum sphenoidale (PS), the sella, the clival recess (CR), and the
internal carotid artery (ICA) canal. Sphenoid septations (arrows) that
deviate laterally attach to the carotid canal.
The most important anatomic structures for the
surgeon are situated laterally. The ICA courses along
the lateral wall from the petrous carotid artery to the
ophthalmic artery (Fig. 103-3). The paraclival segment
is located at the level of the clival recess; the cavernous
segment forms an S-shaped siphon lateral to the sella.
The ICA then courses lateral to the optic nerve to
become the supraclinoid segment and contributes to
the circle of Willis. Deep to the paraclival ICA at the
level of the fl oor of the sella, the sixth cranial nerve
courses superolaterally in Dorello’s canal. The optic
nerves are superomedial to the carotid arteries and
converge at the level of the tubercular strut. Laterally,
the junction of the ICA and the optic nerve is bounded
by the lateral optic-carotid recess (Fig. 103-4). This
recess is formed by pneumatization of the anterior
clinoid process. The medial optic-carotid junction is
Cerebral
part
Cavernous
part
Petrous
part
Cervical
part
Figure 103-3. Segments of the internal carotid artery.

Chapter 103
Endonasal Approach to the Sella and Parasellar Areas 1047
Infl ammatory conditions include acute and chronic
sinusitis, invasive fungal sinusitis, mucocele/mucopyo-
cele, nasal polyposis, and cholesterol granulomas of the
petrous apex. Neoplasms may arise from the mucosal
lining of the sinus or the underlying bone or may
extend into the sinus from the nasal cavity or cranial
cavity. Pituitary tumors are among the most common
neoplasms and may be confi ned to the sella or extend
superiorly to the suprasellar region, laterally to the
cavernous sinus, or anteriorly to the sphenoid sinus.
Tumors arising from bone encountered in this region
include fi brous dysplasia, chordoma, and chondrosar-
coma. Meningiomas frequently involve the planum
sphenoidale and petroclival regions. Sinonasal neo-
plasms that can involve the sphenoid include inverting
papilloma, squamous cell carcinoma, adenocarcinoma,
adenoid cystic carcinoma, and sinonasal undifferenti-
ated carcinoma. Congenital malformations include
meningoceles of the lateral sphenoid recess. Rarely,
traumatic injuries may result in a cerebrospinal fl uid
(CSF) leak within the sphenoid sinus or compression
of the optic nerve.
PREOPERATIVE EVALUATION
Symptoms of sphenoid disease are often nonspecifi c
and patients may remain asymptomatic or attribute
their minor symptoms to “sinus disease.” When head-
aches occur, they are poorly localized and may be expe-
rienced in a frontal or occipital location. Neoplastic
disease may be associated with mild epistaxis or nasal
obstruction. Patients should be queried about associ-
ated symptoms from involvement of adjacent structures,
such as visual loss, diplopia, and facial hypoesthesia.
Neoplastic invasion of the sella may result in symptoms
of hypopituitarism.
Physical examination of a patient with suspected
sphenoid sinus pathology should include nasal endos-
copy to look for intranasal pathology and assess the
patency of the sphenoid ostia. Assessment of cranial
nerve function includes visual acuity, motility of the
extraocular muscles (cranial nerves III, IV, and VI), and
midfacial sensation (V2). A complete ophthalmic evalu-
ation by a neuro-ophthalmologist is indicated if there
is evidence of orbital involvement.
A computed tomography (CT) scan of the sinuses
is essential to establish a differential diagnosis and
determine the extent of disease. Magnetic resonance
imaging (MRI) provides complementary information
and is helpful in narrowing the diagnostic possibilities.
It is especially helpful for visualizing tumor involving
the dura and perineural extension and in differentiat-
ing soft tissue from obstructed secretions.
PREOPERATIVE PLANNING
Preoperative consultation with specialists in other disci-
plines may include ophthalmology, endocrinology, and
neurosurgery, depending on the initial symptoms and
fi ndings. Complete evaluation of visual function may
establish the urgency of surgery in patients with visual
ON
IOCR
ICA
S
mOCR
Figure 103-4. Cadaveric dissection with a view of the right optic
nerve (ON) and internal carotid artery (ICA). The pneumatization
of the anterior clinoid forms the lateral optic-carotid recess (lOCR).
The medial junction of the ON and ICA is the medial optic-carotid
recess (mOCR).
ICA
S
S
S
S
Figure 103-5. The left cavernous segment of the internal carotid
artery (ICA) is dehiscent and susceptible to injury. A lateral sphenoid
septation (S) attaches to the carotid canal.
nounced in patients with acromegaly. The prominence
of the optic canals depends on the degree of pneuma-
tization of the sinus; the optic nerves may be at risk in
patients with posterior extension of the ethmoidal air
cells (Onodi cell). An Onodi cell may be recognized
on preoperative radiographs by horizontal septations
within the sphenoid sinus on a coronal view or by an
oblique anterior sphenoid wall on an axial view.
PATIENT SELECTION
Indications for an endonasal approach to the sphenoid
sinus include infl ammatory disease, benign and malig-
nant neoplasms, congenital malformations, and trauma.

1048
Section 11
Cranial Base Surgery
loss and their potential for recovery. Testing of
pituitary function determines the need for hormonal
replacement, especially perioperative coverage with
stress steroids. Collaboration with a neurosurgeon is
recommended for surgeries that involve the cranial
base.
Radiologic imaging with CT of the sinuses or skull
base is used to plan the best approach (laterality) and
to look for variations in normal anatomy (pneumatiza-
tion, lateral sphenoid septations, Onodi cell, course of
the ICA) that may create technical problems during
surgery. Intraoperative image guidance is very helpful
in surgical approaches to the sella and is used routinely
with an image guidance protocol consisting of detailed
scanning of the skull base. A CT angiogram provides
bony detail with visualization of the ICA. When normal
anatomy is obscured, image guidance can help direct
the trajectory to the sella and avoid one that is too high
and risks a CSF leak. It is also helpful in identifying
anatomic structures beneath the bone surface, such as
the ICA and optic nerves, and delineating the margins
of pathology. Tumors that have a signifi cant soft tissue
interface (intracranial, orbital, or infratemporal skull
base extension) are also imaged with MRI, and a fusion
image is created for intraoperative guidance.
SURGICAL APPROACHES
The sella and surrounding areas may be approached
unilaterally when disease is very limited. A bilateral or
binarial approach is preferred in most cases because of
improved visualization and increased room for instru-
mentation. The basic approach to the sella may be
expanded in any direction, depending on the pathol-
ogy, and may include a transplanum approach for su -
prasellar lesions,2 a transclival/transodontoid approach
for lower clival lesions, and a transpterygoid approach
for access to the lateral recess of the sphenoid and
middle fossa.5
Techniques
The patient is positioned in a supine position and reg-
istration with an image guidance system is instituted. If
immobility of the head is desired, the head is fi xed in
position with a Mayfi eld clamp, and the image guidance
registration is transferred to the head holder; other-
wise, a mask or tracker secured to the skull is used to
track the position of the head. The nasal cavity is decon-
gested with pledgets soaked in oxymetazoline, and the
anterior nares are prepared with povidone-iodine
solution.
The potential need for a reconstructive fl ap must
be considered at the beginning of the surgery.4 If expo-
sure of the ICA or dura is anticipated, a septal mucosal
fl ap is elevated at the beginning of surgery. It is elevated
opposite the side that requires greater exposure. The
inferior aspect of the middle turbinate on one side
(right side for a right-handed surgeon) is resected to
provide additional room for the endoscope during the
later stages of surgery (see Video 103-1). The inferior
turbinate is lateralized and the sphenoid ostium is visu-
alized (see Video 103-2). A needle-tip electrocautery is
used to incise the mucosa and perichondrium/perios-
teum of the nasal septum while leaving a 5-mm margin
at the skull base and nasal vestibule (see Video 103-3).
The incision extends along the junction of the nasal
septum and nasal fl oor to the inferior surface of the
sphenoid sinus. A vascular pedicle containing the pos-
terior nasal artery and extending from the sphenoid os
to the inferior sphenoid surface is preserved. The fl ap
is elevated deep to the perichondrium/periosteum and
displaced into the oropharynx for later reconstruction
(see Video 103-4).
The posterior septum is incised with a Cottle eleva-
tor at its attachment to the sphenoid rostrum, and
mucosa is elevated from the contralateral sphenoid
surface and resected (see Video 103-5). If bleeding
from the contralateral posterior nasal artery is encoun-
tered, it is controlled with monopolar or bipolar elec-
trocautery. The bone of the rostrum is removed in the
midline with bone rongeurs to create an opening into
both sphenoid sinus air cells. The posterior 1 to 2 cm
of the transected septum is resected with back-biting
rongeur to enhance binarial exposure (see Fig. 103-2)
(see Video 103-6). The anterior face of the sphenoid
sinus is then resected with Kerrison rongeurs to maxi-
mize the sphenoidotomy (see Fig. 103-1). Laterally,
bone is removed to the edge of the pterygoid (vidian)
canal, which is located inferolateral to the lateral recess
of the sphenoid sinus. Superiorly, bone is removed to
the planum sphenoidale. This may require opening the
posterior ethmoid air cells for visualization. Resection
of soft tissue and bone anterior to the planum sphenoi-
dale in the midline is minimized to avoid injury to
olfactory nerves and possible CSF leak. Additional room
for instrumentation can be gained by removing thick
bone along the fl oor of the sphenoid sinus with a drill
(4-mm diamond hybrid bit).
Both nasal passages can now be used for instrumen-
tation. The sphenoid sinus is inspected to confi rm the
location of the sella, carotid arteries, and optic nerves
(Fig. 103-6). The relationship of sphenoid septations to
these structures is determined, and the septations are
carefully removed with rongeurs or a drill (see Video
103-7). Aggressive removal of lateral septations that
attach to the carotid canal can result in vascular injury.
Although sinus mucosa can be preserved when remov-
ing small pituitary tumors, it is usually stripped from the
sinus to improve visualization of bony landmarks and
to prepare the surgical bed for reconstruction with the
septal mucosal fl ap or fat grafts.
In patients undergoing pituitary surgery, the bone
over the sella is thinned with the drill and fractured
with an elevator. The bone fragments are elevated from
the dura of the sella and removed. Removal of bone
continues to the margin of the cavernous sinus with a
1-mm angled Kerrison rongeur (Fig. 103-7) (see Video
103-8). The tip of the rongeur should be directed paral-
lel to the cavernous ICA to avoid perforating the vessel.
The ICA is especially prone to injury at the medial
optic-carotid recess, where the ICA deviates medially
before passing lateral to the optic nerve. Opening of

Chapter 103
Endonasal Approach to the Sella and Parasellar Areas 1049
strut of bone can then be fractured and elevated from
the superior intercavernous sinus. Bleeding from the
sinus is controlled by gentle application of hemostatic
material. The dura can now be opened in the midline
to avoid injury to the optic nerves, and the superior
intercavernous sinus is transected to provide maximal
visualization.
Pathology that extends into the lateral recess of the
sphenoid sinus requires a transpterygoid approach if
the sinus is well pneumatized.5,6 A middle meatal antros-
tomy is performed on the side of the pathology, and
the sphenopalatine foramen is identifi ed (see Video
103-9). The overlying bone is removed with a 1-mm
angled Kerrison rongeur to expose the contents of the
pterygopalatine space (Fig. 103-9) (see Video 103-10).
The vessel is cauterized with bipolar electrocautery and
transected. The soft tissues of the pterygopalatine space
are elevated from the underlying pterygoid bone medi-
ICA
ICA
CR
Sella
ON
S
S
S
S
Figure 103-6. Endoscopic view of the sphenoid sinus and bony
landmarks after bilateral sphenoidotomy and resection of the poste-
rior nasal septum. CR, clival recess; ICA, internal carotid artery; ON,
optic nerve; S, lateral sphenoid septation.
Sphenoid
sinus
Pituitary
Figure 103-7. The extent of resection of the anterior face of the
sphenoid sinus, posterior nasal septum, and sella is outlined.
the dura and removal of pituitary pathology are then
performed in conjunction with a neurosurgeon. The
otolaryngologist maintains visualization with the endo-
scope while the neurosurgeon uses two hands to dissect
the tumor. For tumors that have suprasellar extension,
a transplanum approach is combined with a transsellar
approach (Fig. 103-8). The bone of the planum sphe-
noidale over the dura is thinned with a drill (3- to 4-mm
hybrid diamond bit) until it is thin enough to fracture
and elevate from the dura. Drilling should be limited
to the midline initially until the course of the optic
nerves is well visualized. Continuous irrigation when
drilling is essential to prevent thermal injury to the
optic nerves. Once the bone of the sella and posterior
planum is removed, the remaining strut of bone along
the tuberculum sellae is thinned laterally adjacent to
the middle clinoid (medial optic-carotid recess). The
Sphenoid
sinus
Pituitary
Figure 103-8. The planum sphenoidale and sella may be removed
in continuity to provide access to tumors with suprasellar extension.
SPA
SPF
PtPF
Figure 103-9. A left antrostomy has been performed and the sphe-
nopalatine artery (SPA) exposed at the sphenopalatine foramen
(SPF). Overlying bone is removed to expose the pterygopalatine
space (PtPF).

1050
Section 11
Cranial Base Surgery
ally and displaced laterally. The vidian artery and nerve
are identifi ed at the point where they exit the pterygoid
canal, and additional bone superolateral to the ptery-
goid canal is removed to open the lateral recess (Fig.
103-10). The lateral recess is bounded superolaterally
by the foramen rotundum (second division of the tri-
geminal nerve) and the fl oor of the middle cranial fossa
(Fig. 103-11). Wide exposure requires sacrifi ce of the
vidian artery and nerve. The vidian artery courses su -
perolateral to the ICA and is a key landmark for iden-
tifi cation of the second genu of the ICA (Fig. 103-12).7
The surrounding bone is drilled to the plane of the
petrous ICA, starting with removal of bone inferiorly
from the 3-o’clock to the 9-o’clock position (see Video
103-11). This avoids injury to the ICA until the depth
of the artery can be ascertained. Identifi cation of the
course of the petrous ICA is a prerequisite for addi-
tional dissection of the petrous apex and parasellar
region.8
Any dural defects are repaired with inlay and onlay
fascial grafts; a synthetic dural substitute may be used.
The septal mucosal fl ap is then retrieved from the oro-
pharynx and rotated to cover the grafts and exposed
bone (Fig. 103-13). If there is a deep space that is not
suitable for contouring of the fl ap, the space is fi rst
obliterated with an abdominal fat graft to create a
planar surface for the fl ap. The fl ap is covered with a
layer of oxycellulose (Surgicel) followed by a synthetic
glue (DuraSeal). This is supported by nasal tampons or
a Foley urinary catheter infl ated with saline to counter-
act intracranial CSF pressure. The nasal septum is pro-
tected with Silastic splints.
POSTOPERATIVE CARE
In the absence of a CSF leak, any nasal packing is
removed in 1 to 2 days. If dural repair has been per-
formed, packing is maintained for 5 to 7 days. Prophy-
CR
Sella
Figure 103-10. The contents of the left pterygoid canal (arrows)
have been exposed and the surrounding bone has been drilled. CR,
clival recess.
PtC
FR
Figure 103-11. The lateral recess of the sphenoid sinus is bounded
laterally by the pterygoid canal (PtC) inferiorly and the foramen
rotundum (FR) superiorly.
ICA
Figure 103-12. The pterygoid canal (arrow) is a reliable landmark
for locating the petrous internal carotid artery (ICA) at the second
genu.
Figure 103-13. A right septal mucosal fl ap (arrows denote margins)
has been transposed to cover the defect in the skull base.

Chapter 103
Endonasal Approach to the Sella and Parasellar Areas 1051
laxis with oral antibiotics is maintained as long as the
nasal packing is in place. Patients are instructed to use
a saline nasal spray after the packing is removed and to
avoid strenuous activities that may increase intracranial
pressure, such as nose blowing, bending, and lifting.
Silastic nasal splints are maintained for 1 week if a septal
mucosal fl ap is not harvested and for 3 weeks if it has.
Protection of the exposed cartilage with Silastic splints
prevents desiccation and promotes mucosalization.
After the splints are removed, saline irrigation is insti-
tuted to prevent the accumulation of crust. Gentle
endoscopic débridement of crust is performed periodi-
cally during the fi rst month while taking care to not
disrupt the dural repair. Healing is usually complete
within 3 months, and the nasal crusting diminishes.
Patients are monitored for evidence of a CSF leak
in the fi rst few weeks postoperatively. Most CSF leaks
are apparent once the nasal packing is removed and are
characterized by clear rhinorrhea that is often unilat-
eral, a reservoir sign, and occasionally, low-pressure
headaches. When the diagnosis is questionable, the leak
is confi rmed by testing of a rhinorrhea sample for β2-
transferrin. Most leaks are managed by early surgical
intervention consisting of endoscopic repair and place-
ment of a lumbar spinal drain for 3 to 5 days.
COMPLICATIONS
Complications associated with the endonasal approach
to the sella and parasellar areas can be categorized as
nasal, vascular, and neural. Most otolaryngologic com-
plications are minor but have a signifi cant impact on
quality of life: sinusitis, chronic rhinitis with nasal
crusting, loss of olfactory function, nasal synechiae
and obstruction, septal perforation, minor epistaxis,
decreased tearing, and palatal or facial hypoesthesia.
Patients require signifi cant postoperative care with
endoscopic removal of nasal crusts for approximately 3
months after surgery. A subset of patients will continue
to have problems, however, especially after radiation
therapy. Although a binarial approach increases the
potential for nasal crusting, it appears that use of a
septal fl ap greatly decreases the amount of crusting in
the sphenoid region. Loss of olfactory function (and
decreased taste) is observed for several months after
surgery and probably refl ects a combination of factors:
mucosal edema, nasal obstruction from crusting, and
some loss of olfactory mucosa. A transpterygoid ap -
proach often results in loss of vidian nerve function.
Most patients will not notice an appreciable change in
tearing except in situations in which tearing is normally
increased: emotional tearing, windy conditions, and
cold weather. Dissection posterior to the sphenopala-
tine artery can injure the descending palatine nerve
and result in palatal hypoesthesia. The infraorbital
nerve may be injured along the roof of the maxillary
sinus or at the foramen rotundum and result in numb-
ness of the cheek.
Dreaded complications of endonasal surgery
include injury to the ICA and optic nerves. These inju-
ries can be avoided with a good understanding of endo-
scopic anatomy and its variations and by careful surgical
technique. Most injuries to the ICA occur at the medial
optic-carotid recess, where the ICA deviates medially.
The vidian artery is a reliable landmark for locating the
petrous ICA at the second genu (see Fig. 103-8). Injury
to the optic nerve may occur as a result of direct trauma
or thermal injury from electrocautery or drilling. The
presence of an Onodi cell should be determined pre-
operatively to avoid injury during opening of air cells.
CSF leaks are a common sequela of endonasal skull
base surgery and should be anticipated. A trajectory to
the sphenoid sinus that is too high risks violation of the
skull base through the posterior ethmoid air cells or
planum sphenoidale and can be avoided by visualizing
the inferior attachment of the nasal septum to the
rostrum and using image guidance intraoperatively.
SUMMARY
The sphenoid sinus is the starting point for endonasal
approaches to the sella and ventral skull base. A binarial
approach maximizes visualization and allows bimanual
dissection. The parasellar areas can be visualized by
extending the sphenoidotomy superiorly or laterally.
Reliable anatomic landmarks within the sphenoid sinus
are used to avoid injury to the ICA and optic nerves.
PEARLS
• The need for a septal mucosal fl ap for
reconstruction should be considered before
performing a sphenoidotomy.
• The safest area to open the sphenoid sinus is in the
midline at the sphenoid rostrum.
• The lateral recess of the sphenoid sinus extends
between the pterygoid canal and the foramen
rotundum.
• Lateral septations of the sphenoid sinus attach to
the carotid canal.
• The lateral optic-carotid recess is a useful landmark
for visualizing the course of the optic nerve and the
ICA; it is formed by pneumatization of the anterior
clinoid.
PITFALLS
• A high trajectory to the sphenoid sinus may result in
violation of the planum sphenoidale and a CSF leak.
• Monopolar electrocautery should not be used within
the sphenoid sinus because of the risk of injury to
the ICA or optic nerve.
• The ICA deviates medially at the medial optic-
carotid recess and may be injured when opening the
sella.
• An unrecognized Onodi cell can result in injury to
the optic nerve.
• The increased tortuosity of the carotid arteries in
acromegalic individuals results in a narrowed
surgical fi eld.

1052
Section 11
Cranial Base Surgery
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sis and relationship to the internal carotid artery. Laryngoscope
117:1338-1342.
8. Snyderman CH, Kassam AB, Carrau R, Mintz A: Endoscopic
approaches to the petrous apex. Op Tech Otolaryngol 17:168-173,
2006.

Chapter 104
Endoscopic Management of Cerebrospinal
Fluid Leaks
Ricardo L. Carrau, Allan D. Vescan, Carl H. Snyderman, and Amin B. Kassam
A cerebrospinal fl uid (CSF) leak implies a fi stula
between the subarachnoid space and the sinona -
sal tract. Patients with CSF leaks have symptoms
such as clear nasal discharge and headache or compli-
cations such as pneumocephalus, meningitis, or a brain
abscess. Immediate identifi cation plus repair of a CSF
fi stula avoid the development of life-threatening
complications.1,2
CSF leaks can be classifi ed in a number of ways.
Etiology, anatomic site, age of the patient, and underly-
ing intracranial pressure are the most common classifi -
cation systems used. Etiologic classifi cation can be
subdivided into traumatic and nontraumatic in origin.
In the traumatic category, leaks can be either accidental
or iatrogenic. Most CSF leaks are caused by trauma-
induced fractures of the cranial base or by injuries pro-
duced during endoscopic sinus surgery or cranial base
surgery. CSF leaks are diagnosed in 3% of patients suf-
fering closed head injuries and in up to 30% of patients
with a fracture of the skull base.3 Similarly, iatrogenic
trauma such as that caused by traditional cranial base
surgery and endoscopic sinus surgery is associated with
CSF leaks. Endoscopic sinus surgery remains one of the
most common causes of CSF rhinorrhea despite an
overall incidence of 1% in patients undergoing such
surgery.4-21 Nontraumatic CSF leaks may occur second-
ary to tumors of the skull base, congenital malforma-
tions, or high-pressure hydrocephalus (HPH). The
etiology of HPH includes tumors, trauma, infections,
and hemorrhagic cerebrovascular accidents (CVAs).
Occasionally, no cause is identifi ed for the HPH and it
is therefore deemed “idiopathic.”
Multiple techniques have been reported for the
repair of a CSF fi stula. In 1952, Hirsch described the
fi rst endonasal repair of CSF rhinorrhea with a septal
fl ap.22 Subsequently, Montgomery described his experi-
ence with septal fl aps through an external nasal
approach to treat CSF rhinorrhea.23 In 1976, McCabe
reported his experience with the use of osteomucoperi-
osteal fl aps from the septum or middle turbinate
through an external ethmoidectomy approach.24 In
1989, a publication of McCabe’s updated experience
reported a 100% closure rate with follow-ups of 1.6 to
22 years.25 The use of these and other local fl aps to treat
CSF fi stulas via an endoscopic approach was subse-
quently reported.13,26
In 1985, Calcaterra27 described the use of free
muscle or fascia grafts to treat CSF fi stulas via an exter-
nal ethmoidectomy approach, and in 1989, Papay
and colleagues28 described an endoscopic technique.
Multiple publications followed with reports of the use
of free grafts or local fl aps, or both, for the repair
of CSF fi stulas. Recently, a vascularized nasoseptal
fl ap has been devised to reconstruct skull base de -
fects of various causes, and early follow-up data
have revealed a remarkable improvement in CSF fi stula
rates after expanded endonasal approaches to the skull
base.29
The availability of biologic material and the experi-
ence and familiarity of the operating surgeon with
various techniques are the most important factors infl u-
encing the choice of which technique is used during
endoscopic endonasal closure of CSF fi stulas. Most
techniques yield similar results in experienced hands,
as confi rmed by a meta-analysis of the literature by
Hegazy and coworkers.1 After analyzing all reports in
the English literature, these authors found no signifi -
cant differences in outcome regardless of which surgi-
cal technique or which homologous material was used
for the repair.
1053

1054
Section 11
Cranial Base Surgery
PATIENT SELECTION
Diagnosis plus management of a CSF leak involve three
critical steps: distinguishing a CSF leak from other
sources of rhinorrhea, locating the fi stula, and ruling
out high intracranial pressure secondary to altered CSF
dynamics.
Clinical diagnosis of a CSF leak is based on a history
of clear, watery nasal drainage that is generally unilat-
eral and commonly associated with headache. Increased
rhinorrhea when the patient leans over, tilts the head
forward, or performs a Valsalva maneuver further sug-
gests the presence of a CSF leak. A history of tumor,
trauma, or previous surgery involving the paranasal
sinuses or cranial base heightens the level of suspicion.
Occasionally, a life-threatening complication arising
from the CSF leak, such as pneumocephalus, brain
abscess, or ascending bacterial meningitis, may be the
initial manifestation.
Conditions such as vasomotor rhinitis and sympa-
thetic denervation can cause profuse rhinorrhea that
may be confused with a CSF leak. Nasal irrigation fl uid
used during endoscopic sinus surgery or as part of post-
operative care may accumulate in the paranasal sinuses
and later manifest as postoperative rhinorrhea. Thus,
biochemical testing is indicated to confi rm the true
nature of the nasal drainage. CSF will be high in glucose
and low in protein. However, normal nasal discharge
has been shown to be falsely positive for glucose in 45%
to 75% of cases.30 β2-Transferrin is a protein found in
CSF, aqueous humor, and perilymph, but not in blood
or nasal secretions; therefore, β2-transferrin is a reliable
chemical marker of CSF leakage.31-35 In addition to β2-
transferrin,
a
new
chemical
marker
called
β-trace protein is being explored for the diagnosis of
CSF fi stula.36
PREOPERATIVE PLANNING
When CSF rhinorrhea develops after sinus surgery, the
endoscopic surgeon typically has an impression about
the possible site of injury to the cranial base (i.e., site
of the CSF fi stula).
Therefore, a thorough endoscopic offi ce examina-
tion of the nasal cavity may identify the site of leakage.
Fistulas with low-pressure leaks are diffi cult to identify,
especially in the presence of postoperative tissue edema
and blood clots.
Intrathecal injection of contrast material and radio-
active tracers has been advocated to confi rm a CSF leak
and identify the site of origin. Intrathecal fl uorescein
may be used to aid in the diagnosis and localization of
a CSF leak. During this test, 0.5 mL of fl uorescein at a
concentration not greater than 5% is diluted with
10 mL of CSF obtained through lumbar puncture and
then injected intrathecally. Fluorescein is neurotoxic,
so a low-concentration, low-volume injection is manda-
tory to avoid the neurologic complications associated
with higher concentrations. After intrathecal injection
of the fl uorescein solution, the CSF leak may be visual-
ized with a nasal endoscope.31-35,37 Under Wood’s lamp
(i.e., black light), fl uorescein will appear as bright
yellow-green. The yellowish color of fl uorescein may
also be identifi ed without the need for special
lighting.
The logistics of performing a lumbar puncture in
an outpatient setting and medicolegal considerations
(the fl uorescein drug package insert includes an advi-
sory warning against intrathecal use) have discouraged
us from using this technique. Intrathecal injections are
rarely critical to identifi cation of a CSF fi stula. Excep-
tional patients are those with multiple fi stulas, such as
those patients who have suffered skull base fractures,
and the rare patient with repeated episodes of menin-
gitis in the absence of an apparent cranial base defect
or other predisposing factors such as rhinosinusitis or
otitis media.
Others have advocated intrathecal injection of air,
which can “bubble” out at the fi stula site and therefore
aid in identifi cation.37 Air, however, is an irritant to the
brain and may induce seizures. Normal saline solution
may be injected into the intrathecal space to increase
the pressure within the subarachnoid space and thus
aid in identifi cation of the leak.
Scintigraphy with indium-111 has been advocated
for the identifi cation of a CSF leak. Radiotracing is a
very sensitive test; however, it is associated with a high
false-positive rate31 and has a poor resolution that pre-
cludes establishing the specifi c point of leakage. In
general, we do not advocate scintigraphy. In our prac-
tice, the presence of a CSF leak is ascertained with β2-
transferrin electrophoresis, and its site of origin is
identifi ed by computed tomography (CT) scanning,
magnetic resonance imaging (MRI), or CT cisternogra-
phy, with or without endoscopy (Fig. 104-1).
An important consideration in a patient with spon-
taneous rhinorrhea or rhinorrhea after skull base
trauma is to distinguish whether the CSF rhinorrhea is
arising from the sinonasal tract or from other sites such
as the middle ear or mastoid (Fig. 104-2). A CSF fi stula
in the temporal bone may drain into the nose through
the eustachian tube. Imaging is critical to locate the site
of the fi stula. Radiographically, high-resolution com-
puted tomography (HRCT) can be used to identify a
cranial base defect. HRCT is our preferred initial
imaging study to aid in identifi cation of the site of
injury and its extent (Fig. 104-3). HRCT with contrast
enhancement also provides information about the pos-
sibility of intracranial complications that occur in the
setting of acute trauma (iatrogenic or accidental), such
as hematoma or brain contusion. HRCT with views
taken at a plane perpendicular to the suspected site
of injury better evaluates the integrity of the bony
wall in question. Coronal CT views are best to evaluate
defects of the cribriform plate, fovea ethmoidalis,
or planum sphenoidale, whereas axial views are supe-
rior for evaluation of the posterior wall of the frontal
or sphenoid sinuses. We use MRI to ascertain the
contents of a meningocele or meningoencephalocele
(Fig. 104-4).
HRCT, however, may not identify small areas of
surgical trauma or linear nondisplaced fractures. In this

Chapter 104
Endoscopic Management of Cerebrospinal Fluid Leaks 1055
Figure 104-1. Coronal CT cisternogram demonstrating a right
cribriform defect leading to a post-traumatic cerebrospinal fl uid
fi stula (arrow).
Figure 104-2. Coronal CT cisternogram demonstrating bilateral
tegmen defects with contrast material penetrating through existing
defects (arrows).
Figure 104-3. Coronal CT scan demonstrating a defect in the right
cribriform plate after trauma as the cause of the cerebrospinal fl uid
fi stula (arrow).
Figure 104-4. Sagittal magnetic resonance image demonstrating
large meningoencephaloceles of the anterior cranial base (arrow).

1056
Section 11
Cranial Base Surgery
case, HRCT can be used in conjunction with intrathecal
injection of contrast material to identify the fi stula. CT
cisternography has been documented to be both sensi-
tive and reliable. Water-soluble nonionic contrast agents
with less associated toxicity, headache, nausea, and
arachnoiditis have replaced metrizamide. Identifi cation
of the fi stula with contrast-enhanced studies, however,
requires the presence of an active leak. Intermittent
leaks that are temporarily sealed by swelling, infl amma-
tion, or brain herniation may yield a false-negative
result. Intrathecal injection of saline solution to increase
the CSF pressure, “a saline challenge,” enhances the
sensitivity of the test.
Others have suggested MR cisternography to com-
plement the information offered by HRCT without the
need for an intrathecal contrast agent.38 In our experi-
ence, however, this technique has yielded inconsistent
results.
SURGICAL TECHNIQUE
Ethmoid Sinus Roof and Cribriform Plate
If a CSF leak is suspected during endoscopic sinus
surgery, the overlying mucosa should be refl ected away
to closely examine the area and determine the extent
of injury. An inlay or onlay free tissue graft may be used
to patch the site of injury.
Fascia lata, temporalis muscle, abdominal fat, septal
or middle turbinate mucosa or composite grafts, peri-
osteum, and perichondrium are all suitable grafting
materials. Whenever possible, the dural edges are
undermined with a small elevator and the edges of the
graft are tucked between the dura and bone (i.e., epi-
dural inlay graft). Alternatively, the dura may be sepa-
rated from the brain, and the inlay graft may be placed
in the subdural space. When an inlay graft is not possi-
ble because of technical diffi culties, because the fi stula
involves a linear fracture that does not expose the dural
defect, or because dissection of the dura may place
neurovascular structures at risk, the graft is placed as
an onlay over the defect (outside the cranial cavity).
Free muscle or fat grafts can also be used as a
dumbbell–type plug. Fibrin glue, platelet-rich serum, or
other biologic glue may be used to increase the adhe-
siveness of the muscle or fascia graft.
The graft is supported in place with layers of
Gelfoam or Gelfi lm (Upjohn Co., Kalamazoo, MI), fol-
lowed by packing of bacitracin-impregnated gauze or
sponge packing. The use of Gelfoam or Gelfi lm (or
both) prevents adherence of the packing material to
the graft, thereby preventing accidental avulsion when
the packing is removed 3 to 7 days after surgery.
Alternatively, a vascularized tissue fl ap may be fash-
ioned with mucoperichondrium from the middle turbi-
nate or septum and harvested transnasally. If the fi stula
involves the cribriform plate, the mucosa and bone of
the lateral aspect of the middle turbinate are removed
and the remaining mucoperiosteal fl ap is rotated to
cover the defect or cover a muscle or fascia free graft.
Similarly, the mucosa and bone of the lateral aspect of
the middle turbinate may be removed to cover a defect
of the fovea ethmoidalis. An additional option includes
removal of mucosa from a portion of the ipsilateral
septum, removal of the corresponding septal cartilage
or perpendicular plate of the ethmoid, and rotation of
the contralateral mucoperichondrial fl ap to cover the
defect. The fl ap is then supported by Gelfoam or Gelfi lm
(or both) and bacitracin-impregnated gauze. This type
of septal fl ap is the preferred fl ap for defects of the
planum sphenoidale that may not be reached by middle
turbinate fl aps (i.e., defects that are posterior to the
posterior attachment of the middle turbinate). Recently,
we have been using the Hadad-Bassasteguy fl ap, which
consists of a septal mucoperichondrial/mucoperiosteal
fl ap based on the posterior septal artery. The entire
mucoperichondrium/mucoperiosteum may be har-
vested on one side to cover very large defects of the
skull base.
Exposure of the entire defect is essential. In fact,
exposure of the defect may be a more important factor
in determining success of the repair than its size or
site.39
Sphenoid Sinus
The sphenoid sinus can be approached transseptally or,
preferably, through a direct endoscopic approach such
as the one described for pituitary surgery. CSF leaks
involving the sphenoid sinus are amenable to a repair
that includes obliteration of the sinus. After proper
identifi cation of surgical landmarks such as the carotid
canal, optic nerve canal, and optic carotid recesses and
establishing the extent of the defect identifying the
leak, the sinus mucosa is thoroughly removed. Onlay or
inlay free tissue grafts are placed and the sinus is then
obliterated with abdominal free fat. Anteriorly, the
exposed fat is covered with a layer of Surgicel followed
by Gelfi lm, and the nose is packed with a 1/2-inch nasal
strip that has been impregnated with antibiotic
ointment.
An intraoperative CSF leak arising from the sella
turcica during pituitary surgery can most often be
repaired by obliterating the sella with free fat and
reconstructing the fl oor of the sella with a free bone or
cartilage graft harvested during the endoscopic
approach.41 Thus, it does not require postoperative
packing or removal of the entire mucoperiosteum of
the sinus. The previously described Hadad fl ap has
been very effective in repairing these defects.
The risk of accidental injury to adjacent neurovas-
cular structures is a critical consideration when dealing
with defects at the lateral wall of the sphenoid sinus.
Adequate visualization of this area is mandatory. Leaks
that arise in the lateral recess present technical diffi cul-
ties as a result of poor visualization after a traditional
sphenoidotomy (Fig. 104-5). Repair often requires liga-
tion of the sphenopalatine artery and extension of the
sphenoidotomy toward the pterygopalatine fossa.42 The
transpterygoid approach can be combined with endo-
scopic medial maxillectomy as necessary to allow ade-

Chapter 104
Endoscopic Management of Cerebrospinal Fluid Leaks 1057
quate range of motion and visualization of even the
most lateral of sphenoid defects. Through this extended
lateral approach to the sphenoid sinus the endoscopic
surgeon is now able to use a zero-degree scope and
straight instruments to replace angled scopes and
working around corners (Fig. 104-6).
Frontal Sinus
CSF leaks involving the frontal sinus are usually repaired
via a transfrontal sinus approach. The Draf III
approach,43 which involves medial widening of the
frontal recesses and removal of the superior nasal
septum and inferior frontal sinus septum, may provide
exposure of leaks around the frontonasal recess, thus
allowing endoscopic repair.
POSTOPERATIVE MANAGEMENT
As previously mentioned, the general principles of man-
aging a CSF fi stula include adjunctive measures that
may facilitate healing of the repair, including avoidance
of activities that raise intracranial pressure, such as
straining, leaning forward, or lifting weights greater
than 15 pounds. Other measures include bed rest, stool
softeners, 30- to 45-degree elevation of the head of the
bed, sneezing with an open mouth, and absolute avoid-
ance of nose blowing. “Deep extubation” to prevent
straining and coughing is used, and positive pressure
mask ventilation is contraindicated.
The use of prophylactic antibiotics for the preven-
tion of meningitis in patients with CSF fi stulas con -
tinues to be controversial. However, antibiotics are
warranted when the patient has an active sinus
infection. In patients with indwelling lumbar catheters,
prophylactic antibiotics are routinely administered,
and although the concept is not universally accepted,
antibiotics are believed to decrease the incidence
of catheter-related infections.44 The routine use of
antibiotics for traumatic CSF leaks is not of proven
effi cacy, however, and may select resistant bacteria.45
Nonetheless, we do favor the use of perioperative
prophylactic antibiotics during repair of the CSF leak.
Antibiotics are continued until the nasal packing is
removed.
A postoperative CT scan without contrast enhance-
ment in the fi rst 24 hours after surgery is important to
rule out evidence of intracranial bleeding, parenchymal
injury, or tension pneumocephalus. We favor a routine
CT scan of the brain, even in the absence of any neu-
rologic defi cit.
In our practice, we work in conjunction with a neu-
rosurgical team during the repairs; although we do not
consider it necessary in all cases, neurosurgical consul-
tation provides an important perspective on intraopera-
tive and postoperative management, especially on the
need for a CSF drain or a shunt. A lumbar drain with
a designated amount of CSF removed daily based
on CSF production is helpful to control intracranial
pressure, but it is used only for patients suspected of
having HPH. Overdrainage should be avoided because
it creates negative intracranial pressure (i.e., suction
effect) that may result in pneumocephalus and promote
bacterial contamination of the CSF with resultant
meningitis.
High-Pressure Hydrocephalus
Normal intracranial pressure ranges from 5 to 15 cm
H2O when the patient is in the supine position. However,
intracranial pressure increases with positional changes,
with the Valsalva maneuver, and during rapid eye move-
ment (REM) sleep. Increased intracranial pressure, or
HPH, is defi ned as sustained or intermittent pressure
of 20 to 30 cm H2O.4-8 Post-traumatic, postsurgical, and
Figure 104-5. Coronal CT scan of the sphenoid sinus depicting the
limit of visualization of a traditional sphenoidotomy (green dots). The
lateral recess of the sphenoid sinus can be visualized with a transptery-
goid approach (red dots). The diagonal arrows point to the medial
pterygoid plates. The vertical arrow points to a bone defect of the right
middle cranial fossa.
Figure 104-6. Endoscopic view using a zero-degree scope of the
left lateral recess of the sphenoid sinus via a transpterygoid approach
(arrow).

1058
Section 11
Cranial Base Surgery
postinfectious hydrocephalus can result from obstruc-
tion of the arachnoid villi, thus preventing adequate
CSF reabsorption with subsequent increased intraven-
tricular pressure. In post-CVA, post-traumatic and post-
surgical hydrocephalus, the obstruction arises from
subarachnoid hemorrhage, whereas in the case of infec-
tion, infl ammatory changes are responsible for obstruct-
ing the arachnoid villi (Fig. 104-7).46-51
Radiation therapy causes vascular changes in the
brain and elevation of CSF protein, scarring, and adhe-
sions, all of which may contribute to impairment of CSF
reabsorption. Likewise, meningitis causes scarring of
the CSF cisterns and absorptive sites, thus leading to
chronic hydrocephalus.46-48
Patients with recurrent CSF leaks, a past history of
head or cranial base trauma (or both), and a history of
cranial base surgery and those with “spontaneous” CSF
leaks are considered at high risk for HPH and are
enrolled in the following protocol (Fig. 104-8).52 The
CSF leak is repaired via an endonasal endoscopic
approach by following surgical principles such as ade-
quate exposure, hemostasis, preparation of the fi stula
for grafting, and stabilization of the graft. A lumbar
spinal drain is inserted intraoperatively or immediately
after surgery. Three to 5 days postoperatively, the
lumbar spinal drain is clamped, and if no CSF leak is
identifi ed for 24 hours, the drain is removed. Twenty-
four to 48 hours later, a lumbar puncture is performed
to measure CSF opening pressure. A ventriculoperito-
neal (VP) shunt is recommended if CSF opening pres-
sure is elevated. IF CSF opening pressure is normal, the
patient is discharged home and monitored in our out-
patient offi ces.
Patients with CSF leaks in the sphenoid sinus are
treated by obliteration of the sinus with abdominal fat,
which is then stabilized with nasal packing. A postopera-
tive lumbar spinal drain is not required. A lumbar punc-
ture is performed 3 to 5 days postoperatively to measure
opening pressure and establish the need for a VP
shunt.
In patients with normal CSF opening pressure,
a CT scan of the brain is performed 6 weeks after
surgical closure. Ventriculomegaly of the temporal
horns or transependymal edema will identify patients
with HPH who may have escaped identifi cation (false
negative).
CSF leaks in patients who did not have any of the
previously mentioned high-risk factors are repaired
endoscopically and without the use of a spinal drain.
Nasal irrigation with nasal saline solution plus
gentle débridement of crusting is started 1 week
postoperatively.
Figure 104-7. Axial CT scan of the head in a patient with high-
pressure hydrocephalus and ventriculomegaly of the temporal
horns.
High-risk patient:
“Spontaneous” CSF fistula
Recurrent CSF fistula
Hx of:
Head trauma
SBS
Subarachnoid hemorrhage
Sphenoid sinus obliteration
and nasal packing
Intraoperative lumbar
spinal drain
3-5 days post-op measure
CSF opening pressure
Normal CSF pressure
Discharge home
Elevated CSF pressure
CT 6 weeks post-op
VP shunt
Figure 104-8. Management algorithm for patients at high risk for
high-pressure hydrocephalus and failure of repair of a cerebrospinal
fl uid (CSF) fi stula. CT, computed tomography; Hx, history; SBS, skull
base surgery; VP, ventriculoperitoneal.

Chapter 104
Endoscopic Management of Cerebrospinal Fluid Leaks 1059
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PEARLS
• Early identifi cation plus repair of CSF fi stulas avoids
the development of life-threatening complications.
• Most traumatic CSF leaks will heal with conservative
management.
• Endoscopic repair is as successful as open repair
given localization of the leak.
• β2-Transferrin is an extremely reliable marker for CSF
leak because it is found only in CSF, perilymph, and
vitreous humor.
• A CT cisternogram with water-soluble contrast
material is a very useful localizing study in cases in
which intrathecal fl uorescein is not used.
PITFALLS
• Traumatic CSF fi stulas after skull base fracture are
often multifocal in nature.
• Failure of CSF fi stula repair is frequently a result of
inadequate exposure versus inadequate repair.
• High-pressure hydrocephalus is a factor in failure of
CSF fi stula repair.
• Intrathecal administration of an inappropriate
concentration of fl uorescein can lead to neurologic
sequelae.
• Positive pressure ventilation should be avoided in
the immediate postoperative period to prevent
pneumocephalus.
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Laryngoscope 110:1166-1172, 2000.
2. Bernal-Sprekelsen M, Bleda-Vazquez C, Carrau RL: Ascending
meningitis secondary to traumatic cerebrospinal fl uid leaks. Am
J Rhinol 14:257-259, 2000.
3. Dagi FT, George ED: Management of cerebrospinal fl uid leaks.
In Schmidek HH, Sweet WH (eds): Operative Neurosurgical
Techniques: Indications, Methods and Results. Orlando, FL,
Grune & Stratton, 1988, pp 49-69.
4. Wigand ME: Transnasal ethmoidectomy under endoscopic
control. Rhinology 19:7-15, 1981.
5. Hoffman DF, May M: Endoscopic sinus surgery—experience with
the initial 100 patients. Trans Pa Acad Ophthalmol Otolaryngol
41:847-850, 1989.
6. Kainz J, Stammberger H: The roof of the anterior ethmoid: A
place of least resistance in the skull base. Am J Rhinol 3:191-199,
1989.
7. Benninger MS, Mickelson SA, Yaremchuk K: Functional endo-
scopic sinus surgery: Morbidity and early results. Henry Ford
Hosp Med J 38:5-8, 1990.
8. Levine HL: Functional endoscopic sinus surgery: Evaluation,
surgery, and follow-up. Laryngoscope 100:79-84, 1990.
9. Sterman BM, DeVore RA, Lavertu P, Levine HL: Endoscopic
sinus surgery in a residency training program. Am J Rhinol 4:207-
210, 1990.
10. Duplechain JK, White JA, Miller RH: Pediatric sinusitis. The role
of endoscopic sinus surgery in cystic fi brosis and other forms of
sinonasal disease. Arch Otolaryngol Head Neck Surg 117:422-
426, 1991.

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Cranial Base Surgery
37. Kelly TF, Stankiewicz JA, Chow JM, et al: Endoscopic closure of
postsurgical anterior cranial fossa cerebrospinal fl uid leaks. Neu-
rosurgery 39:743-746, 1996.
38. Sillers MJ, Morgan CE, Gammal TE: Magnetic resonance cister-
nography and thin coronal computerized tomography in the
evaluation of cerebrospinal fl uid rhinorrhea. Am J Rhinol 11:387-
392, 1997.
39. Weber R, Keerl R, Draf W, et al: Management of dural lesions
occurring during endonasal sinus surgery. Arch Otolaryngol
Head Neck Surg 122:732-736, 1996.
40. Carrau RL, Jho HD, Ko Y: How I do it: Transnasal-transsphenoi-
dal endoscopic surgery of the pituitary gland. Laryngoscope
106:914-918, 1996.
41. Gjuric M, Goede U, Keimer H, Wigant ME: Endonasal endo-
scopic closure of cerebrospinal fl uid fi stulas at the anterior
cranial base. Ann Otol Rhinol 105:620-623, 1996.
42. Al-Nashar IS, Carrau RL, Herrera A, Snyderman CH: Endoscopic
transnasal transpterygopalatine fossa approach to the lateral
recess of the sphenoid sinus. Laryngoscope 114:528-532,
2004.
43. Weber R, Draf W, Kratzsch B, et al: Modern concepts of frontal
sinus surgery. Laryngoscope 111:137-146, 2001.
44. Janecka IP, Sen C, Sekhar LN, et al: Cranial base surgery: Results
in 183 patients. Otolaryngol Head Neck Surg 110:539-546,
1994.
45. Sen C, Snyderman CH, Sekhar LN: Complications of skull base
operations. In Sekhar LN, Janecka IP (eds): Surgery of Cranial
Base Tumors. New York, Raven Press, 1993, pp 831-839.
46. Fuhrmeister U, Ruether P, Dommatsch D: Alterations of CSF
hydrodynamics following meningitis and subarachnoid hemor-
rhage. In Shulman K, Marmarou A, Miller JK (eds): Intracranial
Pressure IV. Berlin, Springer Verlag, 1980, pp 241-244.
47. Bagley C Jr: Blood in the cerebrospinal fl uid: Resultant functional
and organic alterations in the central nervous system. Part B:
Clinical data. Arch Surg 17:39-81, 1928.
48. Brown JK: Mechanisms of production of raised intracranial pres-
sure. In Minns RA (ed): Problems of Intracranial Pressure in
Childhood. London, MacKeith Press, 1991, pp 13-35.
49. Vale FL, Bradley EL, Fisher WS III: The relationship of subarach-
noid hemorrhage and the need for postoperative shunting.
J Neurosurg 86:462-466, 1997.
50. Noren G, Greitz D, Hirsch A, Lax I: Gamma knife radiosurgery
in acoustic neuromas. In Tos M, Thomsen J (eds): Acoustic
Neuroma. Amsterdam, Kugler, 1992, pp 289-292.
51. Duong D, O’Malley S, Sekhar L, Wright D: Postoperative hydro-
cephalus in cranial base surgery. Skull Base Surg 10:197-200,
2000.
52. Carrau RL, Snyderman CH, Kassam AB: The management of CSF
leaks in patients at risk for high-pressure hydrocephalus. Laryn-
goscope 115:205-212, 2005.

Chapter 105
Reconstruction after Skull Base Surgery
Ricardo L. Carrau, Allan D. Vescan, Carl H. Snyderman, and Amin B. Kassam
The goals of reconstruction after any oncologic resec-
tion are preservation and rehabilitation of function,
restoration of cosmesis, and avoidance of morbidity.
Any reconstruction after anterior craniofacial resection
should strive to separate the cranial cavity from the
upper aerodigestive tract, obliterate the dead space,
preserve neurovascular and ocular function, and restore
cosmesis (Table 105-1). Multiple free tissue grafts,
vascularized local fl aps, free microvascular fl aps,
and allografts are available for these purposes (Table
105-2).
PATIENT SELECTION
Any patient who requires a skull base resection that
produces a pathway of communication between the
cranial cavity and the upper aerodigestive tract will
need some form of reconstruction. Before embarking
on reconstruction of the surgical defect, key patient
factors must be considered, including underlying
medical comorbid conditions such as diabetes mellitus
and peripheral vascular disease and, most importantly,
the size and site of the defect. It is often the complexity
of the resection that dictates the option most suitable
for reconstruction. Defects may involve a signifi cant
volume of soft tissue and facial or cranial bones, and
there may be functional concerns such as resection of
walls of the orbit or communication with the oral cavity.
An important point to consider with respect to patient
selection is what additional treatments may be required.
Postoperative radiation therapy is often necessary after
oncologic resection of malignant tumors of the skull
base. Vascularized tissue is superior to any other source
to avoid the complications of radiation therapy.
PREOPERATIVE PLANNING
Estimation of the extent of resection by thorough analy-
sis of the preoperative imaging studies, including
computed tomography (CT) and magnetic resonance
imaging, is fundamental in planning the reconstruction
and obtaining informed consent. In addition, angiog-
raphy may be necessary to assess for peripheral vascular
disease if a free microvascular fl ap is necessary. Doppler
ultrasonography is another technique available to assess
fl ow through vessels that supply the possible regional
or free fl aps.
It is important to communicate with other team
members regarding the types of reconstruction being
considered. Frequently, the members of the skull base
team who perform the ablation may be different from
the ones who perform the reconstruction.
SURGICAL TECHNIQUES
Pericranial Flap/Galeopericranial Flap
The majority of defects after anterior craniofacial resec-
tion involve the area of the anterior skull base located
between the orbits and extending from the crista galli
anteriorly to the planum sphenoidale posteriorly (Fig.
105-1). This area is amenable to reconstruction with a
pericranial or galeopericranial fl ap.1-3 Both pericranial
and galeopericranial fl aps are vascular pedicled fl aps
supplied by the supraorbital and supratrochlear vessels
(Fig. 105-2). Thus, sacrifi ce of the supraorbital and
supratrochlear vessels would render the pericranial fl ap
nonviable. Harvesting of the pericranial fl ap does not
impair the blood or sensory supply to the remaining
1061

1062
Section 11
Cranial Base Surgery
the galea. Both tissue layers are raised as a single unit
with a combination of sharp and blunt dissection
extending from the bicoronal incision to the supraor-
bital neurovascular bundles. Additional length could be
gained by planning harvesting of the fl ap distal to the
bicoronal incision. We prefer to harvest the pericranial
fl ap at the end of surgery (Fig. 105-3) to prevent desic-
cation and avoid inadvertent injury to the fl ap during
the extirpative part of the operation. The fl ap is inserted
under the supraorbital and craniotomy bone grafts to
cover the anterior skull base defect (Fig. 105-4). Com-
pression of the fl ap by the supraorbital bone graft
should be avoided.
Temporalis Muscle Flap
Defects of the anterolateral and infratemporal skull
base, as well as defects of the orbit, oral cavity, orophar-
ynx, and nasopharynx, may be reconstructed with a
temporalis muscle fl ap.4-6 This muscle fl ap may be
divided vertically to reconstruct two separate defects
(i.e., subtemporal skull base and orbit), or most com-
monly, the anterior half of the muscle is used for recon-
struction and the posterior half is transposed anteriorly
Table 105-1
GOALS OF RECONSTRUCTION
Separation of cranial cavity from upper aerodigestive
tract
Obliteration of dead space
Function
neurovascular
ocular
Cosmesis
Table 105-2
MATERIALS FOR RECONSTRUCTION
Free tissue grafts
Vascularized fl aps
Pericranial/galeal
Temporalis muscle
Forehead
Scalp
Facial
Free microvascular fl aps
Rectus abdominis
Radial forearm
Latissimus dorsi
Allografts
Plates/mesh
Bone cement
Scalp
Orbit
Dura/Brain
Orbit
Figure 105-1. Intraoperative photograph demonstrating the defect
after anterior craniofacial resection.
scalp. Both fl aps can be designed to reach the clival
region or be divided longitudinally to reconstruct two
different defects (i.e., anterior skull base and nose or
orbit).
The pericranium comprises the periosteum and
the areolar tissue that separates the periosteum from
Figure 105-2. The vascular supply of both pericranial and galeo-
pericranial fl aps includes the supratrochlear and supraorbital vessels
(arrows).
Pericranium
Figure 105-3. Intraoperative photograph demonstrating a pericra-
nial fl ap.

Chapter 105
Reconstruction after Skull Base Surgery 1063
to fi ll the anterior temporal fossa. In our practice, the
temporalis muscle fl ap is most commonly used to
provide soft tissue cover for the bone grafts or titanium
mesh used for reconstruction of the orbital walls, to
reconstruct the infratemporal fossa or skull base, or to
obliterate the orbital cavity after exenteration. A tem-
poralis muscle fl ap may be used as an adjunct to a
pericranial fl ap when resection of the skull base has
been extended laterally (Fig. 105-5).
The temporalis muscle fl ap is harvested by dissect-
ing the temporalis muscle from the temporal fossa with
a combination of electrocautery and blunt dissection.
Its insertion to the zygoma (superfi cial and deep layers
Pericranium
A
B
Figure 105-4. A, Intraoperative photograph of a pericranial fl ap
inset between the dura and skull base. B, Pericranial fl ap seen from
the nasal side (arrows).
A
Temporalis Muscle
Tongue
Pericranial Flap
Superior Orbital Rim
B
Figure 105-5. A, Intraoperative photograph of reconstruction of
the skull base and orbit with the temporalis muscle. B, Postoperative
appearance.
of the deep temporal fascia) should be transected to
gain adequate mobilization. To protect the frontal
branches of the facial nerve, the superfi cial layer of the
deep temporal fascia is incised along an imaginary line
that extends from the superior orbital rim to the root
of the zygoma. The plane of dissection proceeds deep
to this fascial layer, which corresponds to a subperios-
teal plane over the zygomatic arch and malar process.
Its reach or arc of rotation may be increased by dividing
the insertion of the temporalis muscle to the coronoid
process of the mandible.
The muscle is then rotated and sutured into place.
If the posterior half was not used, it is transposed ante-
riorly and sutured to the lateral orbital rim and to a
curvilinear plate screwed at the level of the temporal

1064
Section 11
Cranial Base Surgery
line. The temporalis muscle fl ap is supplied by the deep
temporal artery, a terminal branch of the internal max-
illary artery. Dissection of the fl ap in its medial aspect
or oncologic resection or preoperative embolization of
the muscular branches of the internal maxillary artery
will render the fl ap nonviable.
Temporoparietal Fascia Flap
The temporoparietal (superfi cial temporal fascia) fascia
fl ap is supple and offers an extended reach that allows
it to be used for reconstruction of anterior, lateral, and
posterior skull base defects, as well as maxillofacial
defects.7-13 It can be harvested bilaterally as two separate
fl aps or as a bipedicle fl ap, which may provide enough
tissue to reconstruct the entire anterior skull base.
The temporoparietal fascia fl ap includes the super-
fi cial temporal fascia and galea, which is supplied by the
superfi cial temporal artery. Its vascular supply encom-
passes an area that extends from the ipsilateral tempo-
ral artery to the midline and covers up to 15 cm in width
(Fig. 105-6). It is critical to plan harvesting of this fl ap
in advance. To preserve its integrity and blood supply,
the fl ap should be harvested at the time of the bicoro-
nal incision. Because a customary hemicoronal or bicor-
onal incision would divide the fl ap and sacrifi ce its
blood supply, anterior harvesting of the fl ap should be
limited to the hairline since the frontal branch of the
facial nerve may be injured if the dissection is extended
anterior to this point. To harvest the temporoparietal
fascia, the coronal incision is extended to but not
through the galea, and the fl ap is then harvested by
sharp dissection. The dissection is somewhat cumber-
some and tedious because of the rich blood supply of
the scalp. Hemostasis is achieved with bipolar cautery.
Microvascular Free Flaps
Microvascular free fl aps lengthen the time of surgery
and increase its cost and morbidity, so these fl aps are
recommended only in certain situations, such as the
need to reconstruct a defect left by an extended resec-
tion that includes all the soft tissues from the skin to
the brain, to support the brain, after extended maxil-
lectomies that produce defects that will not retain a
prosthesis, or when local or regional fl aps are not avail-
able.3,11,12,14-17 Contraindications to the use of free fl aps
include severe peripheral vascular disease, lack of avail-
ability of adequate host vessels, medical instability, and
the need for vasopressors. Commonly used microvascu-
lar free fl aps include the radial forearm fl ap, the rectus
abdominis fl ap, and the latissimus dorsi fl ap (Fig.
105-7). A thorough discussion of these fl aps is included
in Chapter 81.
Reconstruction of the Craniofacial Skeleton
Wires, stitches, titanium alloy plates, or mesh may be
used to fi x free bone grafts such as the craniotomy
bone, the supraorbital block, and other parts of the
maxillofacial skeleton18-21 (Fig. 105-8). We prefer the
use of plates or mesh because they yield stable fi xation
and a more predictable long-term result. Titanium
plates and mesh osseointegrate very well; in addition,
they produce minimal imaging artifact and radiation
scattering. Titanium mesh can also be used to replace
parts of the bony framework that had to be resected,
such as frontal bone, orbital bone, or anterior maxilla
(Fig. 105-9). We cover the mesh with acellular dermis
to prevent subsequent indentation of the skin over the
mesh pattern.
Reconstruction of the Orbit
Reconstruction of the orbital walls is recommended
when more than a third of the circumference of the
orbit is sacrifi ced (i.e., more than the lamina papyra-
cea) or when the periorbita had to be removed with
the adjacent bony wall.18-21 This latter defect produces
signifi cant enophthalmos and may also lead to hypo-
ophthalmia in the case of resection of the orbital
fl oor.
The orbital walls are better reconstructed with rigid
materials that resist contraction and provide an imme-
diate and predictable outcome. This can be achieved
with bone grafts, titanium mesh, porous polyethylene,
or other alloplastic material. We generally use titanium
A
B
Temporoparietal Fascia Flap
Figure 105-6. A, Intraoperative photograph demonstrating dissec-
tion of a temporoparietal fascia fl ap. B, Temporoparietal fascia fl ap.

Chapter 105
Reconstruction after Skull Base Surgery 1065
A
Mandible
Infratemporal
Fossa
Temporal
Fossa
LD Flap
B
Figure 105-7. A, Extensive anterior and lateral skull base and intra-
oral defect. B, Postoperative photograph demonstrating a nasocuta-
neous fi stula and retraction of the left oral commissure. A latissimus
dorsi (LD) free microvascular fl ap has a tendency to sag because of
its bulk and weight.
mesh because of its availability and ease of conforming
to the orbital walls (Fig. 105-10). Another consideration
when choosing the reconstructive material is that these
patients usually require postoperative radiation therapy,
which raises the possibility of osteoradionecrosis of
bone grafts. Titanium mesh, however, needs to be
covered with an acellular dermis graft over the orbital
side or the soft tissues of the orbit will “grow” into the
mesh holes and lead to tethering of the extraocular
muscles and severe contraction of the lower eyelid
(i.e., ectropion). The medial canthus is repositioned
with a titanium plate that is screwed to the remaining
nasal bones (Fig. 105-10). The lateral canthus should
also be repositioned and sutured to the lateral orbital
rim to avoid lower eyelid ectropion.
POSTOPERATIVE CARE
Postoperatively, the patient is transferred to an inten-
sive care unit for continuous cardiovascular and neuro-
logic monitoring. Postoperative anemia, hypovolemia,
A
B
Figure 105-8. A, Fixation of bone grafts with sutures. B, Fixation
of bone grafts with titanium plates.
and electrolyte imbalances are corrected when
present.
A CT scan of the brain is performed on the fi rst or
second postoperative day to identify intracranial com-
plications such as cerebral contusion, edema or hemor-
rhage, fl uid collections, or pneumocephalus.
The scalp drains are kept on bulb suction only.
High-pressure suction can produce rapid shifting of the
brain or brain stem (or both), with life-threatening
effects. Drains are removed when the drainage is less
than 30 mL/day. If the dura was opened or resected
during the ablation, the drain puncture site should be
closed with an encircling stitch on removal of the drain
to prevent infection.
COMPLICATIONS22-25
Scalp Wound
Necrosis of the scalp is rare and most often the result
of poorly designed incisions or prolonged use of hemo-
static clamps. The latter may result in areas of ischemia,
particularly around the auricle, that can make the tissue
susceptible to secondary infection. Scalp necrosis may

1066
Section 11
Cranial Base Surgery
A
Acellular Dermis
B
Acellular Dermis
C
also be the result of previous irradiation, which when
combined with harvesting of the galeopericranial fl ap,
may render the scalp ischemic.
Postoperative intracranial infection usually results
from inadequate separation between the cranial cavity
or grafts and the sinonasal tract, from a large dead
space, or from noncompliance and blowing the nose in
the immediate postoperative period. Partial necrosis of
the scalp fl ap may lead to a wound infection, as well as
contamination of the grafts. Restoration of the separa-
tion between the cranial cavity and the sinonasal
tract, débridement (removal of the free bone grafts),
and prolonged antibiotic therapy (45 days, guided by
culture and sensitivity testing) are the recommended
treatment.
Postoperative Sinonasal Bleeding
Signifi cant postoperative nasal bleeding most com-
monly arises from a branch of the internal maxillary or
anterior ethmoidal artery and is amenable to endo-
scopic control. Angiography with embolization is
reserved for patients in whom the bleeding site is not
readily apparent, such as those who underwent recon-
struction with a microvascular free fl ap. Intracranial
postoperative bleeding or bleeding from the vascular
anastomosis of a free microvascular fl ap requires surgi-
cal intervention.
Cerebrospinal Fluid Leak
In a patient with postoperative rhinorrhea, testing of
the fl uid for β2-transferrin is prudent to confi rm a cere-
brospinal fl uid (CSF) leak. Accumulation of irrigation
fl uid in the sinonasal tract, with subsequent drainage,
can mimic a CSF leak in the immediate postoperative
period.
A postoperative CSF leak is managed conservatively
with bed rest, stool softeners, and a lumbar drain (50 mL
every 6 to 8 hours). Persistence of the leak beyond 3 to
5 days, unabated by conservative measures, indicates
the need for surgical repair. Surgical exploration,
however, may be indicated as initial therapy if loss of
the reconstructive fl ap or dehiscence of the dural repair
is suspected.
Tension Pneumocephalus
Trapped intracranial air can act as a space-occupying
lesion that compresses the brain parenchyma and gives
rise to lethargy, disorientation, slow mentation, or
hemiparesis. A CT scan without contrast enhancement
Figure 105-9. A, Intraoperative photograph. The frontal and glabellar
area is reconstructed with titanium mesh (arrows). B, Acellular dermis is
layered over the titanium mesh (arrows). C, Postoperative appearance of
frontal contour (arrow).

Chapter 105
Reconstruction after Skull Base Surgery 1067
A
Acellular Dermis
Temporalis Muscle
Flap
B
Nasal Bone
C
Figure 105-10. A, Intraoperative view of a titanium mesh plate used
for reconstruction of the orbital fl oor. A temporalis muscle fl ap will cover
the mesh on its inferior area. The soft tissues of the orbit are separated
from the mesh with acellular dermis to avoid ingrowth of the tissues and
a frozen globe. B, Intraoperative view of a titanium plate used for medial
canthopexy. C, Postoperative photograph demonstrating less lagophthal-
mos and enophthalmos than with traditional techniques.
confi rms the diagnosis and may be used to guide aspira-
tion of the air with a needle placed through a burr hole
or osteotomy gap. Recurrent tension pneumocephalus
is usually associated with loss of the pericranial fl ap or
may be due to nose blowing by a noncompliant patient
despite instructions otherwise. Recurrent pneumoceph-
alus requires bypassing the sinonasal tract airway with a
tracheostomy or endotracheal tube or surgical closure
of any cranionasal communication, or both.
Limitation of Extraocular Muscle Movement
Some degree of postoperative diplopia is present in
most patients and is caused by dissection of the troch-
lea, postoperative edema, or removal of the orbital
walls. It is usually self-limited and typically lasts less than
4 weeks. Reconstructive grafts may entrap the medial,
lateral, or inferior rectus muscles and result in restric-
tion of range of motion and permanent diplopia. Intra-
orbital dissection, such as that required when the
periorbita is resected, or surgery on the cavernous sinus
may injure the motor innervation of these muscles. A
forced duction test helps differentiate between muscle
entrapment and loss of muscle innervation.
Enophthalmos
Enophthalmos is caused by expansion of the volume of
the orbital cavity as a result of resection of the orbital
walls and is more pronounced when the periorbita is
resected. It is best to prevent this complication by recon-
structing the orbital walls with autogenous bone or tita-
nium mesh (i.e., rigid reconstruction).

1068
Section 11
Cranial Base Surgery
7. Har-Shai Y, Fukuta K, Collares MV, Stefanovic PD: The vascular
anatomy of the galeal fl ap in the interparietal and midline
regions. Plast Reconstr Surg 89:64-69, 1992.
8. David SK, Cheney ML: An anatomic study of the temporoparietal
fascial fl ap. Arch Otolaryngol Head Neck Surg 121:1153-1156,
1995.
9. Pinar YA, Govsa F: Anatomy of the superfi cial temporal artery and
its branches: Its importance for surgery. Surg Radiol Anat 28:248-
253, 2006.
10. Pollice PA, Fondel JL Jr: Secondary reconstruction of upper
midface and orbit after total maxillectomy. Arch Otolaryngol
Head Neck Surg 124:802-808, 1998.
11. Telliouglu AT, Tekdemir I, Erdemli EA, et al: Temporoparietal
fascia: An anatomic and histologic reinvestigation with new
potential clinical applications. Plast Reconstr Surg 105:40-45,
2000.
12. Lai A, Cheney ML: Temporoparietal fascial fl ap in orbital recon-
struction. Arch Facial Plast Surg 2:196-201, 2000.
13. Olson KL, Manolidis S: The pedicled superfi cial temporalis fascial
fl ap: A new method for reconstruction in otologic surgery. Oto-
laryngol Head Neck Surg 126:538-547, 2002.
14. Yamada A, Harii K, Ueda K, Asato H: Free rectus abdominis
muscle reconstruction of the anterior skull base. Br J Plast Surg
45:302-306, 1992.
15. Bridger GP, Baldwin M: Anterior craniofacial resection for
ethmoid and nasal cancer with free fl ap reconstruction. Arch
Otolaryngol Head Neck Surg 115:308-312, 1989.
16. Schwartz MS, Cohen JI, Meltzer T, et al: Use of radial forearm
microvascular free-fl ap graft for cranial base reconstruction. J
Neurosurg 90:651-655, 1999.
17. Valentini V, Fabiani F, Nicolai G, et al: Use of microvascular free
fl aps in the reconstruction of the anterior and middle skull base.
J Craniofac Surg 17:790-796, 2006.
18. Janecka IP: New reconstructive technologies in skull base surgery:
Role of titanium mesh and porous polyethylene. Arch Otolaryn-
gol Head Neck Surg 126:396-401, 2000.
19. Badie B, Preston JK, Hartig GK: Use of titanium mesh for recon-
struction of large anterior cranial base defects. J Neurosurg
93:711-714, 2000.
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after temporalis myofascial fl ap transposition: Clinical and radio-
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PEARLS
• Vascularized tissue is preferred over nonvascularized
tissue such as free tissue grafts.
• Local and locoregional fl aps are associated with less
morbidity, less operative time, and less cost than
microvascular free fl aps are.
• Microvascular free fl aps provide better coverage or
support (or both) for defects that include the skin
or lateral skull base.
• Trauma to the skull base tends to produce multiple
defects.
• High ventricular pressure should be suspected in
patients with recurrent CSF leaks.
PITFALLS
• Patients who undergo preoperative radiation or
chemoradiation therapy are at a higher risk for
devascularization of the scalp from harvesting of a
pericranial or galeopericranial fl ap.
• Patients who have undergone radiation therapy are
at higher risk for delayed healing or nonhealing of
the defect.
• No reconstruction provides immediate protection
against high CSF pressure.
• Patients who have skull base defects are at higher
risk for meningitis, even after reconstruction.
• Oncologic resection may destroy the blood supply
to local or regional fl aps.
References
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goscope 111:1719-1725, 2001.
6. Burggasser G, Happak W, Gruber H, Freilinger G: The tempora-
lis: Blood supply and innervation. Plast Reconstr Surg 109:1862-
1869, 2002.

Chapter 106
Transnasal and Transoral Approaches to
the Cervical Spine
Carl H. Snyderman, Ricardo L. Carrau, Amin B. Kassam, and Paul A. Gardner
The superior aspects of the cervical spine (C1 and C2)
are not easily reached from a transcervical route and
have traditionally been accessed through a transoral/
transpalatal approach. Innovations in recent years
include the introduction of endoscopes for assistance
with the transoral approach and the development of a
completely endoscopic transnasal approach. Although
not widely used yet, we believe that the transnasal
approach has distinct advantages that will make it the
preferred technique. The otolaryngologist does not
typically perform cervical spine surgery in isolation but
cooperates with other specialties (neurosurgery, ortho-
pedic surgery) to provide access to the upper cervical
spine. With the transnasal endoscopic approach, the
otolaryngologist maintains an endoscopic view for the
neurosurgeon after the initial exposure is achieved.
Resection of the odontoid process is sometimes
necessary for the treatment of basilar invagination with
brain stem compression. This may be the result of rheu-
matoid degeneration with pannus formation or trau-
matic fracture and dislocation of the odontoid. With
the advent of transnasal endoscopic approaches to the
ventral skull base, resection of the odontoid may also
be performed to provide access to tumors of the foramen
magnum and adjacent areas.
ANATOMY
The transoral and transnasal approaches to C1 and C2
are midline approaches. C1 and C2 articulate with the
skull at the inferior edge of the clivus (foramen
magnum). The dens or odontoid process is covered
anteriorly by the arch of C1. The vertebral bodies are
covered by the paraspinal muscles anteriorly (longus
colli and longus capitis). The body of C2 is typically at
the level of the soft palate. The posterior pharyngeal
wall covers the bodies of C3 and C4. Laterally, the ver-
tebral artery is exposed between C1 and C2, where it
exits the vertebral canal and loops superfi cially. The
parapharyngeal segment of the internal carotid artery
is situated laterally and is not in the surgical fi eld, but
an ectatic artery may occasionally deviate medially into
the retropharyngeal region.
The palatal mucosa receives its blood supply from
the greater palatine vessels, which exit the greater pala-
tine foramina medial to the second molars. The arteries
course anteriorly to supply the mucosa over the hard
palate. Passavant’s ridge is a muscular ridge that is phys-
iologically but not anatomically distinct and provides
contact with the soft palate during nasopharyngeal
closure.
The clivus is the anterior portion of the occipital
bone and extends from the fl oor of the sphenoid sinus
to the foramen magnum. The bone of the clivus thins
as it approaches the foramen. Laterally, the clivus is
bounded by the medial pterygoid plates and the base
of the pterygoids. The pterygoid canal and vidian artery
lead to the second genu of the petrous carotid artery,
which is situated superolaterally. The lateral limit of the
surgical fi eld is the eustachian tube.
PATIENT SELECTION
Indications for surgery on C1 and C2 include infec-
tious, infl ammatory, traumatic, and neoplastic condi-
tions. Infectious problems are rare but could include a
localized retropharyngeal abscess, which is best accessed
directly, and osteomyelitis. Traumatic injuries of C1 and
C2 that compress the spinal cord cannot be repaired
directly but may require decompression of displaced
bone fragments. Stabilization of the spine with poste-
rior fusion is usually necessary.
1069

1070
Section 11
Cranial Base Surgery
The most common indication for surgical ap -
proaches to C1 and C2 is rheumatoid degeneration of
the ligaments with resultant destruction of the odon-
toid and creation of an infl ammatory pannus (Fig. 106-
1). Symptoms are a consequence of cervical instability,
as well as basilar invagination and compression of the
brain stem.
Resection of the lower clivus and odontoid provides
a surgical corridor to tumors at the foramen magnum
(Fig. 106-2). These tumors are a heterogeneous group
consisting of chondrosarcomas, meningiomas, chordo-
mas, and other types. This approach may be combined
with other modules of the expanded endonasal
approach to the ventral skull base to obtain optimal
exposure.1
PREOPERATIVE EVALUATION
Patients with basilar invagination are typically elderly
patients and often have severe pharyngeal dysfunction
at the time of surgery. A complete neurologic examina-
tion with assessment of evidence of long-tract compres-
sion should be performed. The larynx is examined to
evaluate laryngeal function, swallowing, and risk of
aspiration.
Computed tomography (CT) is best suited to assess
changes in bone anatomy, the relationship of C1 to the
lower clivus, and the position of the odontoid. Magnetic
resonance imaging (MRI) is superior for visualization
of the pannus and the amount of brain stem compres-
sion. If an intraoperative navigational system is used, a
CT angiogram is obtained preoperatively for image
guidance. It is necessary to modify the standard scan-
ning protocol to include the upper cervical spine to the
C3 level.
Consultation with an anesthesiologist should be
obtained for evaluation of the airway and consideration
of airway options. Increased diffi culty of intubation
because of cervical instability may be encountered.
There is also a risk of accidental extubation with repo-
sitioning of the patient for posterior cervical fusion if
performed during the same operative setting.
PREOPERATIVE PLANNING
After endotracheal intubation and induction of general
anesthesia, the patient undergoes baseline somatosen-
sory evoked potential (SSEP) monitoring before posi-
tioning. Brain stem evoked responses to monitor brain
stem function may also be indicated. Cervical instability
during repositioning requires continued monitoring,
especially with movement of the patient. The patient is
then placed in Mayfi eld pins in a neutral position, and
postpositioning SSEPs are used to confi rm the safety of
the positioning. Image guidance registration, including
the cervicomedullary junction, is undertaken.
Adequate preparation of the nares or pharynx is
carried out, and the patient is given a third-generation
cephalosporin for perioperative antibiotic prophylaxis.
Topical antibiotics may also be used in this situation
because the entire dissection is usually extradural.
SURGICAL APPROACHES
Although the transoral/transpalatal approach is still
the standard of care at most institutions, we prefer the
transnasal route for decompression of the brain stem.
The transnasal route is limited inferiorly and can reli-
ably reach only the body of C2. If more inferior resec-
tion is needed, a transnasal route can be combined with
a transoral route. A transoral route is contraindicated
Figure 106-1. Basilar invagination with brain stem compression
secondary to rheumatoid pannus (arrow).
Figure 106-2. Neoplasms at the level of the foramen magnum
(arrow) are most commonly chordomas, chondrosarcomas, or
meningiomas.

Chapter 106
Transnasal and Transoral Approaches to the Cervical Spine 1071
in patients with severe trismus and is diffi cult in patients
with a full set of restored teeth.
Transoral/Transpalatal Approach
Surgery may be performed with nasal or oral endotra-
cheal intubation. If the patient is nasally intubated, the
tube can be displaced to one side in the pharynx. Alter-
natively, an oral RAE tube can be held between the
retractor and the tongue. Various retractors (Dingman,
Crockard) are available and allow self-retained retrac-
tion of the mandible and tongue, as well as the lateral
oral commissure (Fig. 106-3). One of the biggest chal-
lenges is fi nding a proper fi t of the tongue blade so that
the base of tongue does not bulge into the fi eld. During
lengthy cases, the retractor should be released for
several minutes intermittently to prevent excessive
tongue pressure and the potential for ischemic necrosis
or edema.
If the superior extent of the resection is the odon-
toid, incision of the palate is not necessary. A red rubber
catheter is passed transnasally and sutured to the soft
palate adjacent to the uvula. It is then retracted to pull
the soft palate into the nasopharynx and secured to the
drapes. If the exposure needs to extend to the rostrum
of the sphenoid, incision of the palate is generally nec-
essary. A paramedian incision is made adjacent to the
uvula and curves in a lazy “S” fashion behind the maxil-
lary alveolus so that the majority of the palatal fl ap is
based on one greater palatine artery. The mucoperios-
teal fl aps are elevated laterally to the edge of the greater
palatine foramen with preservation of the blood supply.
The posterior edge of the hard palate may be resected
to provide additional exposure superiorly.
Electrocautery is used to make a vertical midline
incision in the posterior pharyngeal wall from the level
of C3 to the nasopharynx. The incision continues
through the soft tissues in the midline between the
longus capitis and longus colli muscles. The paraspinal
muscles are elevated from the vertebral bodies and ring
of C1. Excessive lateral dissection is avoided because of
the risk of injuring the vertebral artery. A self-retaining
retractor is placed and the bone work is then performed
with a drill and Kerrison rongeurs. Visualization is
enhanced with use of the operating microscope or even
endoscopes.
After completion of the decompression, the pha-
ryngeal incision is closed in two layers: a deep layer of
interrupted 3-0 polyglycolic acid suture and a superfi -
cial layer of 3-0 polyglycolic acid suture placed with
a vertical mattress technique. Obtaining watertight
closure can be diffi cult at the superior and inferior
limits of the incision. If a palatal incision has been
made, the soft palate incision is closed in two layers: a
deep intramuscular layer of interrupted 4-0 polyglycolic
acid suture and a superfi cial layer of interrupted 4-0
polyglycolic acid suture. The mucoperiosteal fl ap over
the hard palate is thin and closed in a single layer with
a vertical mattress technique. A paraffi n nasal splint can
be molded to the contour of the hard palate and secured
with sutures around the teeth. This protects the palatal
mucosa during mastication.
Transnasal Approach
The technique has been described elsewhere2,3 and is
performed by a surgical team consisting of an otolaryn-
gologist and neurosurgeon operating simultaneously.
The fi rst step is bilateral sphenoidotomy with resection
of the posterior attachment of the nasal septum to the
rostrum of the sphenoid (see Video 106-1). The mucosa
of the posterior nasopharynx is then cauterized and
elevated to expose the underlying paraspinal muscles
(longus capitis and longus colli). The soft tissues and
muscles are then resected to expose the underlying
pharyngobasilar fascia (see Video 106-2). Resection of
this dense fascia is facilitated by using a drill with a 3-
mm coarse diamond bit to remove the cortical bone of
the clivus starting at the sphenoidotomy and progress-
ing inferiorly (see Video 106-3). The limits of exposure
include the eustachian tubes laterally, the fl oor of the
sphenoid sinus superiorly, and the level of the soft
palate inferiorly.
An image guidance system is used to identify the
level of the ring of C1, and the bone is then exposed
(Fig. 106-4). The lower edge of the clivus is thinned
with a drill and resected with a Kerrison rongeur. The
central portion of C1 is then removed with the drill and
the defect is widened laterally with a bone rongeur (Fig.
106-5) (see Video 106-4). The location of the underly-
ing dens is confi rmed with image guidance and the
central portion of the dens is drilled (see Video 106-5).
When only a shell of outer cortical bone remains, the
base of the dens is detached from the body of C2. Blunt
and sharp dissection of the attachments of the dens to
the surrounding pannus allows mobilization and
removal of the remaining bone (Fig. 106-6) (see Video
106-6).
Although resection of the pannus may not be nec-
essary, we prefer to partially resect the pannus with an
ultrasonic aspirator until pulsations transmitted from
the brain stem are observed (see Video 106-7). No
Figure 106-3. A Dingman retractor distracts the mandible and
maxilla and displaces the endotracheal tube, tongue, and cheeks.

1072
Section 11
Cranial Base Surgery
reconstruction is necessary if the dura has not been
violated. The defect is covered with fi brin glue (see
Video 106-8).
Because of inherent instability of the cranioverte-
bral junction in these patients, posterior fusion of the
cervical spine to the occiput is usually performed during
the same operative event.
POSTOPERATIVE MANAGEMENT
These patients are at increased risk for aspiration post-
operatively, and reintubation can be diffi cult because
of posterior neck fusion. Consideration should be given
to leaving the patient intubated postoperatively until a
safe airway can be ensured, or a temporary tracheos-
tomy should be performed. With the transnasal
approach, we have found tracheostomy to be necessary
only in patients with signifi cant preoperative pharyn-
geal dysfunction.
Patients may start a full liquid diet and progress to
a soft diet as soon as they are able to swallow without
aspiration. Formal evaluation with a modifi ed barium
swallow may be helpful in determining swallowing capa-
bility. With the transnasal approach, patients can resume
an oral diet immediately. Return of swallowing function
is often delayed for several days with a transoral route.
If used, nasal septal or palatal splints are removed
1 week postoperatively.
COMPLICATIONS
The transoral/transpalatal approach to the upper cervi-
cal spine and foramen magnum provides limited expo-
SPA
SPA
Vid
Vid
Sphenoid sinus
Sphenoid sinus
Clivus
Odontoid
Odontoid
OC
C1
C2
Sphenoid sinus
Clivus
Odontoid
OC
SPA
Vid
C1
C2
Figure 106-4. The nasopharyngeal soft tissues are resected to
expose the lower clivus and ring of C1. OC, occipital condyle; SPA,
sphenopalatine artery; Vid, vidian artery. (Reprinted with permission
from Kassam AB, Snyderman C, Gardner P, et al: The expanded endonasal
approach: A fully endoscopic transnasal approach and resection of the odon-
toid process: Technical case report. Neurosurgery 57[1 Suppl]:E213, discus-
sion E213, 2005.)
C2
C2
C1
C1
OC
Od
FM
C2
C1
C1
OC
Od
FM
Figure 106-5. The central ring of C1 is removed with a drill and
the gap is widened with a Kerrison rongeur. FM, foramen magnum;
OC, occipital condyle, Od, odontoid. (Reprinted with permission from
Kassam AB, Snyderman C, Gardner P, et al: The expanded endonasal
approach: A fully endoscopic transnasal approach and resection of the odon-
toid process: Technical case report. Neurosurgery 57[1 Suppl]:E213, discus-
sion E213, 2005.)
C2
C2
C1
C1
OC
FM
FM
C2
C1
C1
OC
FM
Figure 106-6. The odontoid is removed with a drill and dissection
of the ligamentous attachments. FM, foramen magnum; OC, occipital
condyle. (Reprinted with permission from Kassam AB, Snyderman C,
Gardner P, et al: The expanded endonasal approach: A fully endoscopic
transnasal approach and resection of the odontoid process: Technical case
report. Neurosurgery 57[1 Suppl]:E213, discussion E213, 2005.)

Chapter 106
Transnasal and Transoral Approaches to the Cervical Spine 1073
sure, especially in patients with impaired jaw opening
or enlarged oropharyngeal tissues. Although C2 and C3
can be exposed with retraction of the soft palate, expo-
sure plus removal of bone of C1 and the lower clivus
are diffi cult, even with a palatal incision. Resection of
the posterior edge of the hard palate provides addi-
tional exposure but increases the risk for a palatal fi stula
postoperatively. Other potential risks include dental
injury, edema or necrosis of the tongue, upper airway
obstruction secondary to edema, dysphagia, pain with
swallowing, nasal regurgitation/hypernasal speech as a
result of palatal incompetence, retropharyngeal hema-
toma or abscess, and temporomandibular joint syn-
drome secondary to excessive opening of the jaw.
Because of concerns about the airway postoperatively,
patients may remain intubated or require a tracheos-
tomy. The angle of approach to the tip of the odontoid
is less than 90 degrees and may hinder visualization with
a microscope and increase the diffi culty of dissection.
Although the introduction of endoscopes through the
oral cavity has the potential of decreasing the extent of
exposure and improving visualization, it does not solve
all these issues.
Palatal dysfunction is a signifi cant problem with
transoral/transpalatal procedures. Palatal incisions
result in some degree of retraction, and partial dehis-
cence of the closure can create a gap at the palatal edge.
Additionally, resection of vertebral bone and retropha-
ryngeal soft tissues increases the distance between the
palate and the posterior pharyngeal wall and prevents
good contact during nasopharyngeal closure. This
results in hypernasal speech and nasal refl ux of liquids.
There is less risk of palatal dysfunction with a transnasal
approach. Because the posterior pharyngeal defect is
above the level of the contact point for the soft palate
and posterior pharyngeal wall (Passavant’s ridge), there
is no risk of hypernasal speech or nasal regurgitation.
Closure of the pharyngeal incision is diffi cult after
a transoral approach, and ongoing contamination of
the wound by saliva with heavy bacterial fl ora can occur.
In contrast, the defect created by a transnasal approach
is above the level of the soft palate and should not be
exposed to the same degree of bacterial contamination.
The wound is protected with a layer of fi brin glue at the
end of the procedure.
The extracranial parapharyngeal segment of the
internal carotid artery is lateral to the fossa of Rosen-
müller and deep to the eustachian tube. On occasion,
a tortuous internal carotid artery may course medially
in the retropharyngeal area. This a relative contraindi-
cation to a transoral approach but would not preclude
a transnasal approach.
Far lateral dissection at the level of C1 and C2 may
injure the vertebral artery and should be performed
only under image guidance.
If a cerebrospinal fl uid (CSF) leak should occur
with a transoral approach, obtaining a watertight closure
can be diffi cult, depending on the length and accessi-
bility of the superior extent of the incision. With the
transnasal approach, there is a greater risk of a dural
opening and CSF leak if dissection is performed in the
region of the occipital condyle superolaterally. A CSF
leak in this area can be effectively sealed with a fat graft
or septal mucosal fl ap.
SUMMARY
The transnasal endoscopic approach to the odontoid is
direct and provides access to the lower clivus, C1, and
body of C2. Visualization with the endoscope is superior
to that with the microscope and facilitates more com-
plete removal of pannus if indicated. The only limita-
tion is the ability to dissect below the body of C2 because
of the level of the hard palate. Avoidance of pharyngeal
and palatal incisions circumvents the potential airway
and swallowing morbidity associated with the transoral
approach. Because the surgical opening is above the
level of the soft palate, palatal dysfunction is avoided
and there is no need to close the mucosal defect. No
infections have been observed. There is also minimal
pain, and patients are able to resume an oral diet imme-
diately if there were no swallowing problems preopera-
tively. A more rapid return to normal function and
avoidance of operative morbidity should result in
shorter hospitalization with decreased cost of care.
PEARLS
• A palatal incision can usually be avoided by
retraction of the soft palate into the nasopharynx
with a catheter sutured to the base of the uvula.
• With a transnasal route, resection of the posterior
nasal septum to the nasal fl oor is necessary to
provide adequate lateral access.
• Resection of the nasopharyngeal mucosa and
underlying muscle and fascia improves exposure of
C1 and C2.
• Removal of a thickened pannus should be
performed until transmitted pulsations are evident;
complete removal risks a CSF leak.
• The inferior extent of the transnasal approach is
limited by the posterior edge of the hard palate.
PITFALLS
• Patients with preoperative pharyngeal dysfunction
are at increased risk for airway problems and should
have a tracheostomy performed at the same time.
• Patients with cervical instability should undergo
neurophysiologic monitoring during positioning and
throughout surgery to avoid neural injury.
• Excessive pressure from an oral retractor can result
in ischemic necrosis of the tongue.
• Loss of retropharyngeal soft tissue and bone
increases the risk for postoperative palatal
insuffi ciency.
• Retropharyngeal dissection lateral to the eustachian
tube should be avoided because of the risk of injury
to the internal carotid artery.

1074
Section 11
Cranial Base Surgery
References
1. Kassam AB, Snyderman CH, Mintz A, et al: Expanded endonasal
approach: The rostrocaudal axis. Part II. Posterior clinoids to the
foramen magnum. Neurosurg Focus 19(1):E4, 2005. Available at

2. Kassam AB, Snyderman CH, Gardner PA, et al: The expanded
endonasal approach: A fully endoscopic transnasal approach and
resection of the odontoid process: Technical case report. Neuro-
surgery 57(1 Suppl):E213, discussion E213, 2005.
3. Kassam AB, Mintz AH, Gardner PA, et al: The expanded endonasal
approach for an endoscopic transnasal clipping and aneurysmor-
rhaphy of a large vertebral artery aneurysm: Technical case report.
Neurosurgery 59(1 Suppl 1):ONSE162-ONSE165, 2006.

section 12
Otology
Chapter 107
Offi ce-Based Procedures in Otology
Alyssa Hackett and Yael Raz
In otolaryngology, as in other surgical disciplines, mini-
mally invasive procedures are increasingly being per-
formed in the offi ce setting. Some even envision a day
when certain otosclerosis patients will routinely undergo
offi ce-based stapedectomy.1
There are many advantages to an offi ce-based surgi-
cal approach.2 The procedures are carried out under
local anesthesia, and patients do not need to abstain
from oral intake. The cost of both the facility and the
anesthesia is signifi cantly lower, and a family member
or friend may be present throughout the procedure.
However, an offi ce-based approach is not appropriate
for every patient. Patients who are poor candidates for
offi ce surgery include those with narrow ear canals or
those whose anatomy makes the procedure too complex;
highly anxious patients; most children, particularly
those who are 3 to 6 years of age; and patients with
neurocognitive defi cits.2
As with any procedure, the key to patient satisfac-
tion is fostering trust between the patient and physi-
cian. Before selecting an offi ce approach to any
procedure, it is imperative that the patient/parent
know what to expect during the procedure. The dura-
tion, noise, pain, and possibility of vertigo are all com-
ponents that may have an impact on overall patient
satisfaction with the experience. Attaching a video
camera to the microscope and allowing the patient to
watch the procedure on a monitor can sometimes
reduce anxiety.
This chapter presents various techniques for anes-
thetizing the ear, as well as commonly performed offi ce
procedures. For foreign bodies involving the external
auditory canal (EAC) or myringoplasty, readers are
referred to Chapters 108 and 113, respectively.
ANESTHESIA
Giving proper care and consideration to anesthetic
options before starting the procedure will minimize
patient discomfort and the propensity to move during
the procedure. Options include topical anesthesia
(often used for myringotomy), local anesthesia (often
used for biopsy of a mass in the ear canal), and regional
blocks (useful for repairing lacerations or draining a
hematoma of the auricle).
Topical Anesthesia of the
Tympanic Membrane
Phenol, lidocaine, and tetracaine are all commonly
used to topically anesthetize the tympanic membrane
(TM). Before initiating anesthesia, an otoscopic exami-
nation should be performed to remove debris from the
ear canal and completely visualize the TM for perfora-
tions, desquamated skin, and retraction pockets. The
anesthetic agent is less effective if it must diffuse through
debris to reach the TM. Perforations may allow anes-
thetic agents to reach the middle ear space and thereby
result in temporary facial nerve palsy or vertigo.3
1075

1076
Section 12
Otology
Phenol
Phenol creates a small chemical burn at the point
where it is directly applied to the TM. Therefore, when
used in large uncontrolled quantities, phenol can cause
signifi cant chemical otitis externa. When used in small
controlled quantities and directly applied to the
eardrum, however, phenol can produce safe, effective,
and rapid anesthesia. It is our preferred anesthetic for
topical application to the TM.
An appropriately sized aural speculum is fi rst used
to visualize the TM. Moisture and debris, if present, are
suctioned from its lateral surface. It is particularly
important to ensure a dry TM when using phenol; oth-
erwise, it will spread and cauterize the entire moist
region. The tip of a phenol applicator is dipped in
phenol such that a small drop is collected between the
prongs (Fig. 107-1). The applicator is gently touched to
the inside of the bottle to remove excess liquid. The
phenol is applied to the area or areas of the TM to be
manipulated (e.g., small dots for intratympanic injec-
tions or linear streaks for myringotomy). Immediate
blanching will occur and indicates that the TM has been
anesthetized. The phenol can also be applied with
cotton over a metal applicator or via a phenol kit with
a prepackaged sponge applicator (see Fig. 107-1).
Patients should be warned that they will experience a
transient burning sensation on application of the
phenol. Used in these small amounts, phenol does not
cause any permanent damage to the TM.
Tetracaine or Lidocaine
The literature does not support a standard concentra-
tion of lidocaine or tetracaine. Solutions of 4% to 10%
lidocaine (amide) or 8% to 16% tetracaine (ester) dis-
solved in isopropyl alcohol are some of the more com-
monly described anesthetics used for TM anesthesia.
The patient is positioned supine with the head
tilted to the side. The anesthetic should be room to
body temperature before use to avoid a caloric effect.
The solution is dropped into an ear canal with an intact
TM until it is fi lled one third to one half full. The solu-
tion must remain in contact with the TM for at least 15
to 20 minutes for lidocaine and 60 minutes for tetra-
caine. A piece of cotton or a wick may be placed in the
ear canal to allow the patient to ambulate during this
time. The wick should be inserted slowly until it makes
contact with the TM to ensure adequate exposure of
the anesthetic to the TM. Before initiating the proce-
dure, the wick is removed and a pick or the tip of the
suction device (disconnected) is used to touch the TM
to assess the effectiveness of the anesthesia. If the patient
experiences pain distinct from noise produced by
touching the TM, the anesthetic should be given more
A
B
C
Figure 107-1. Options for application of phenol to the tympanic
membrane. A, Phenol applicator. B, Cotton on a metal applicator.
C, Prepackaged kit with sponge tip.

Chapter 107
Offi ce-Based Procedures in Otology 1077
time to work. Once adequate anesthesia is achieved, the
residual anesthetic is aspirated from the canal.
EMLA Cream
EMLA (eutectic mixture of local anesthetics) cream
has been used for anesthesia of the eardrum by some
authors. The cream is easy to apply directly to the
eardrum with minimal risk of entry into the middle ear,
but it does not always provide adequate anesthesia.4
This may in large part be attributed to the long latency
period for EMLA’s full potency to be realized. One
hour or more is generally accepted as the appropriate
waiting period after application of EMLA, thus making
it suboptimal for use in a busy offi ce setting.
External Ear and Canal Anesthesia
Biopsy or repair of the external ear can be done in the
offi ce under local anesthesia. It is usually accomplished
with local or regional injection of lidocaine or with a
variety of topically applied anesthetics.
Topical Anesthetics
Topical anesthesia is often a good choice for children
who cannot tolerate injectable anesthetic. EMLA or
LET (lidocaine-epinephrine-tetracaine) is frequently
used on both intact and broken skin.
EMLA or LET is applied directly to the surgical
fi eld while taking care to completely cover the area to
be worked on. A temporary occlusive dressing can be
placed over the medication for a minimum of 30
minutes for LET and 60 minutes for EMLA. Alterna-
tively, LET can be mixed from its components (1% to
4% lidocaine, 1:1000 to 1:2000 epinephrine, 0.5% to
2% tetracaine) and applied with a cotton ball soaked
in the mixture. Finally, a wide variety of commercially
available patches, usually impregnated with lidocaine,
are available for local procedures. Regardless of the
local anesthetic used, it is prudent to test the sensation
of the site with a needle prick or pinprick.
Local Injection of Lidocaine with Epinephrine
Traditionally, epinephrine has not been used for local
anesthesia in regions of the body such as the outer
ear, tip of the nose, fi ngers, toes, and penis because of
the risk of skin necrosis from decreased blood fl ow.
However, several recent studies have shown that epi-
nephrine can be safe for local injection in the ear.5-7
The injection site is sterilized with an alcohol swab
or a surgical preparation of choice. A 1-mL syringe is
fi lled with a solution of 1% lidocaine with 1:200,000
epinephrine. A 1:10 bicarbonate-to-lidocaine dilution
can be formulated to buffer the acidity of lidocaine and
reduce burning at the injection site. This solution must
be used within 1 week of mixing. A 25-gauge or smaller
needle is used to inject the deep dermis. The needle is
inserted under the skin at a 10- to 15-degree angle as
the anesthetic is simultaneously slowly injected until the
entire region to be operated on has been infi ltrated. A
bleb of fl uid can be both visualized and palpated as the
anesthetic is injected. Pain during injection can be
reduced by injecting slowly and minimizing the total
number of skin punctures. A single needle puncture
may be suffi cient to cover small areas. If the skin is
broken, injection can be performed through the open
skin edges. The amount of anesthetic necessary depends
on the size of the fi eld but should be enough to com-
pletely cover the operative fi eld. Despite being used
locally, some of the lidocaine will reach the systemic
circulation. The maximum dose of 1% lidocaine with
epinephrine is 7 mg/kg up to 500 mg or 50 mL. The
maximum dose of lidocaine without epinephrine is
4.5 mg/kg. Lidocaine provides adequate anesthesia
within 2 minutes of injection, and the effect should last
for several hours.
Regional Anesthesia
Regional anesthesia can be used for procedures involv-
ing the auricle, as well as the TM. Four nerves supply
sensation to the ear (Fig. 107-2). The auriculotemporal
nerve, a branch of the mandibular portion of the tri-
geminal nerve, supplies the superior portion of the
outer ear. The great auricular nerve, which originates
from the cervical plexus, supplies the inferior auricle.
The middle section of the outer ear is supplied by the
lesser occipital nerve, another branch of the cervical
plexus. Finally, the auditory branch of the vagus nerve
supplies the concha and the EAC. The EAC also has
some innervation from the auriculotemporal nerve
and branches from the tympanic plexus of the facial
nerve.
Sound knowledge of this anatomy is necessary to
choose an effective regional anesthetic modality. Two
are discussed here: an outer ear block and a four-
quadrant canal block. An outer ear block does not
supply anesthesia to the EAC or the TM. Conversely, a
four-quadrant canal block does not supply anesthesia
to the outer ear but does provide good anesthesia to
the EAC and TM.
Auditory
branch of the
vagus nerve
Auriculotemporal
nerve
Tragus
Lesser occipital
nerve
Auriculotemporal
nerve
Auditory branch of
the vagus nerve
Great auricular
nerve
Helix
Anthihelix
Lesser
occipital
nerve
Concha
Great
auricular
nerve
Lobule
External
auditory
canal
Figure 107-2. Innervation of the auricle. (Adapted from Roberts R,
Hedges JR [eds]: Clinical Procedures in Emergency Medicine, 4th ed. Phila-
delphia, WB Saunders, 2004.)

1078
Section 12
Otology
Outer Ear Block
Injections for an ear block are made at the junction of
the most superior and inferior portions of the auricle
with the head. The injection sites are disinfected with
an alcohol swab, and a 10-mL syringe is fi lled with 1%
lidocaine with epinephrine. A 25-gauge or smaller-bore
needle is positioned at the superior pole. It is inserted
at a 10- to 15-degree angle to the surface of the skin and
directed toward the tragus (Fig. 107-3). The needle is
inserted along the subcuticular plane while drawing
back on the syringe. If no blood is returned as it is
inserted, it can safely be assumed that the anesthetic
can be injected as the needle is withdrawn without
danger of intravenous injection. A total of 2 to 3 mL is
injected. The needle is not completely removed from
its initial puncture site as it is being repositioned to
anesthetize along the posterior aspect of the pinna. A
total of 2 to 3 mL of lidocaine is injected in the same
manner as discussed earlier. The inferior pole is then
injected. Anesthesia is obtained within a few minutes
and lasts for more than one hour.
Four-Quadrant Canal Block
Again, 1% lidocaine with epinephrine is used for anes-
thesia. This technique involves injection at the bony
cartilaginous junction of the EAC. The most medial
aspect of the hair-bearing portion of the EAC can
approximate this junction. A 25- or 27-gauge needle is
used on a small syringe (1 or 3 mL with a Luer-Lok).
The EAC is injected anteriorly, inferiorly, superiorly,
and posteriorly (Fig. 107-4). Slight pressure is applied
with the speculum just lateral to the injection site to
drive the anesthetic medially until blanching of the
bony canal skin is noted. A moderate amount of resis-
tance should be felt when the correct plane is infi l-
trated. If the injection is too superfi cial, a bleb may
occur and hinder view of the canal for the procedure
to be performed. Visualizing the more medial bony
canal during the injection is helpful because blebs
can be recognized early and the injection site may be
adjusted.
DISIMPACTION OF CERUMEN
Disimpaction of cerumen is the most common proce-
dure performed in the offi ce. The ear is normally self
cleaning; it expels cerumen, dust, dirt, and skin cells
through gradual outward migration of the epithelium
of the auditory canal. However, several conditions can
interrupt this process and necessitate cleaning by a phy-
sician. Individuals with a narrow canal who wear hearing
aids or ear plugs, those who have undergone surgery
involving the ear canal, and chronic cotton swab users
are among those most at risk for impaction of
cerumen.
The task of cleaning an ear canal frequently falls
on primary care physicians, with the removal technique
of choice being irrigation of the ear canal. Not every
ear can be completely disimpacted in this manner, and
in the otolaryngologist’s offi ce, direct microscopic visu-
alization is available to manually remove the cerumen.
It is the preferred method when available and has the
added benefi t of providing an opportunity for trainees
Figure 107-3. Outer ear block. (Adapted from Roberts R, Hedges JR
[eds]: Clinical Procedures in Emergency Medicine, 4th ed. Philadelphia, WB
Saunders, 2004.)
Speculum
Syringe
Figure 107-4. Four-quadrant canal block. (Adapted from Roberts R,
Hedges JR [eds]: Clinical Procedures in Emergency Medicine, 4th ed. Phila-
delphia, WB Saunders, 2004.)

Chapter 107
Offi ce-Based Procedures in Otology 1079
to reinforce the skills required for otologic surgery—
working through a speculum, holding instruments in a
manner that does not block view of the canal/TM, and
maintaining fi ne control of the tip of the instrument.
In nearly every situation, cerumen can be removed
without causing discomfort or bleeding.
TECHNIQUE
An appropriately sized aural speculum is inserted into
the ear canal and held in place with the nondominant
hand. Under microscopic vision, cerumen is removed
with suction, wax curettes, or various picks. Loop
curettes can be sharp and should be used with caution.
Ridged spatula-type curettes are less traumatic and
handy when there is a small to moderate amount of
cerumen that does not completely occlude the canal.
If the cerumen forms a complete plug, it should be
manipulated by working at the interface between the
plug and the skin. This allows the physician to follow
the contours of the canal and anticipate variations in
anatomy (i.e., a prominent anterior bulge from the
temporomandibular joint) and enables visualization of
the TM. Depending on the consistency of the wax,
curettes, picks, or suction may be used. A small right-
angled pick is particularly handy in establishing the
plane between fi rm wax and the canal skin. This pick is
also ideal for removing cerumen that is impacted against
the TM. When aspiration is used, a 5F suction device is
generally suffi cient but should be changed to 3F when
close to the TM. A 7F suction device should be used
only when absolutely necessary because the noise gener-
ated can be uncomfortable and it is harder to avoid
inadvertently injuring the skin of the ear canal.
The same principles apply to cleaning a mastoid
cavity. Ideally, one should be familiar with the previous
operative reports and the status of the TM and middle
ear anatomy. The ease of cleaning a cavity depends
greatly on whether proper attention was given to critical
issues at the time of surgery, particularly lowering the
facial ridge suffi ciently, sizing the meatoplasty ade-
quately, and drilling the roof and fl oor of the ear canal
so that they are fl ush with the superior and inferior
aspects of the mastoid bowl. It is important to clear all
pockets of desquamation and cerumen. Frequently,
suctioning the bowl results in dizziness, so cleaning
should rely on picks or curettes when possible. If the
debris is moist, small suction devices should be used in
patients prone to vertigo.
DRAINAGE OF A HEMATOMA OF
THE AURICLE
Hematoma of the auricle is commonly seen in patients
engaged in contact sports such as rugby, boxing, and
wrestling because of the high potential for shearing the
skin and perichondrium off the underlying cartilage.
Wrestling has traditionally accounted for such a large
proportion of auricular hematomas that the term
“wrestler’s ear” is sometimes used to describe the resul-
tant “caulifl ower ear” deformity from an untreated
injury. The requirement for head or ear protection
during wrestling matches has greatly reduced but not
eliminated the incidence of auricular hematoma in this
population.
Cartilage receives its blood supply from the overly-
ing perichondrium. Shearing injuries cause disruption
of the normal anatomic relationship of the perichon-
drium to the cartilage, with resultant cartilage necrosis.
The characteristic appearance of a caulifl ower ear is the
consequence of subsequent fi brosis, contracture, and
neocartilage formation. To reduce this risk, it is impor-
tant that the position of the perichondrium over the
cartilage be restored as soon as possible after the forma-
tion of a hematoma.
Most auricular hematomas are believed to develop
in the potential space between the perichondrium and
cartilage; however, it has recently been shown that
hematomas, particularly those that are recurrent, are
often located intracartilaginously.8 Intracartilaginous
hematomas can be multiloculated and, when incom-
pletely evacuated, have a high potential to cause a cau-
lifl ower ear deformity.
PREOPERATIVE PLANNING
A careful history is important to determine the mecha-
nism of injury and the time course of formation of the
hematoma. A complete otoscopic examination should
also be performed to assess for additional external or
middle ear trauma. It is likewise important to deter-
mine the likelihood that the ear may be reinjured
before it has healed. Athletes, in particular, may be
likely to reinjure the ear because they are often unwill-
ing to miss practice or a competition while the ear is
healing. Bulky compression dressings and needle drain-
age should be avoided in this patient population. Recur-
rent hematomas may require open exploration.
SURGICAL TECHNIQUE
Incision and Drainage
Incision plus drainage is the preferred method for evac-
uation of a hematoma because the risk of recurrence is
lower than with needle aspiration. All hematomas, even
those that are multiloculated and intracartilaginous,
can be successfully managed with this technique. The
ear is appropriately prepared on both its medial and
lateral surfaces. The periaural area should also be
draped in such a fashion that hair is kept out of the
surgical fi eld. Anesthesia of the ear is obtained with a
regional nerve block. An incision is made in the helical
or antihelical fold to conceal the incisional scar (Fig.
107-5). It should be a minimum of 4 to 5 mm or larger
if complete exploration is necessary. Blood or fl uid is
manually expressed from the incision by digital com-
pression. A hemostat may be needed to explore the
cavity and completely evacuate any loculations present.
Once the fl uid has been totally removed, a small rub -
ber band or Penrose drain may be used to prevent

1080
Section 12
Otology
reaccumulation of fl uid (Fig. 107-5). Regardless of
whether a drain is placed, success of the procedure
relies on an adequate compression-type dressing. A
bolster-type dressing sutured to the ear has been shown
to be effective against recurrence while allowing return
to normal activity, including contact sports.9 A dental
roll is cut to the size of the hematoma. For large hema-
tomas involving both the helical and antihelical rims, a
bolster may be necessary at both sites. Size 3-0 silk or
nylon suture is inserted through the dental roll and the
lateral side of the auricle. On the medial side of the
auricle, the suture is passed through another smaller
piece of dental roll and back through the medial
roll, the ear, and the lateral roll to complete the stitch
(Fig. 107-5). The dental rolls and suture are then coated
in antibiotic ointment.
Needle Aspiration
Hematoma of the auricle can be managed by needle
aspiration followed by a period of compressive dressing.
Alhough less invasive, this technique does carry a sig-
nifi cantly higher risk of recurrence. Hematomas that
are very fi rm on palpation are probably composed of
clot and are unlikely to be drained successfully by
needle aspiration. The ear is appropriately prepared on
both its medial and lateral surfaces. Anesthesia of the
ear is obtained with a regional nerve block as detailed
earlier in this chapter. An 18-gauge needle is inserted
into the hematoma and then a syringe is used to evacu-
ate the hematoma. When the needle is withdrawn, the
ear is digitally manipulated to ensure complete evacua-
tion. A bolster is then fashioned and sutured in place
A
B
D
C
Figure 107-5. Hematoma of the auricle. A, The
contours of the pinna are distorted by a hema-
toma. B, The auricle is incised parallel to the
helical rim. C, A Penrose drain is placed, and
trimmed Silastic sheeting is secured to both the
lateral and medial (D) surface of the auricle with
bolster stitches. (Courtesy of Barry E. Hirsch, MD.)

Chapter 107
Offi ce-Based Procedures in Otology 1081
as described earlier. Alternately, some practitioners
prefer to use thermal splints or a whole-ear compressive
dressing.
POSTOPERATIVE MANAGEMENT
After drainage, the patient should be monitored closely
for signs of recurrence or infection. Antibiotics are used
while the bolster is in place. The bolster is removed
within approximately 5 days and patients are observed
closely for recurrence of the hematoma.
INCISION AND DRAINAGE OF
EAR ABSCESS
The external ear is a common site of local infections
that require incision and drainage of a fl uctuant collec-
tion of purulent exudate and necrotic tissue. These
collections can be as small as a furuncle in the canal or
as extensive as a subperiosteal abscess. Draining such
collections not only contributes to their resolution
but also helps alleviate some of the patient’s pain and
discomfort by releasing pressure and tension on the
involved tissue. As with most infections, there is an
increased incidence of these types of infections in
immunocompromised hosts and diabetics.
Obstruction and infection of hair follicles resulting
in a painful collection of purulent exudate give rise to
furuncles and carbuncles. The most common location
for them to develop on the ear is in the cartilaginous
canal, with Staphylococcus aureus being the most frequent
causative pathogen. These infections will sometimes
drain spontaneously or after treatment with warm com-
presses and manual manipulation. Furuncles that are
persistent require incision and drainage for resolution.
Antibiotics are seldom necessary but should be consid-
ered in cases with signifi cant concomitant cellulitis.
Although furuncles and carbuncles often develop
without a history of trauma, allowing the organism to
gain access to the skin, perichondritis and chondritis of
the auricle are frequently associated with trauma or
cosmetic cartilage piercing. Perichondritis, or infl am-
mation of the perichondrium, and chondritis, or infl am-
mation of the cartilage, may lead to frank abscess
formation and require incision and drainage. Débride-
ment may be necessary to contain or resolve the
infection.
The auricular cartilage is relatively avascular, with
a consequent diminished capacity to both clear an
infection and deliver systemic antibiotics at adequate
minimal inhibitory concentrations. Antibiotics are of
use for intralesional therapy during prolonged drain-
age,10 but evidence is inconclusive concerning the effi -
cacy of systemic antibiotics.11-13 In complicated infections
requiring hospital admission, transdermal iontopho-
retic antibiotics should be considered because they
have been found to be superior to diffusion of antibiot-
ics through the skin or through the eschar of a burn.14
Samples should be taken for culture at the time of
drainage/débridement and broad-spectrum antibiotics
started. Although S. aureus is the pathogen most fre-
quently isolated, Pseudomonas aeruginosa is common in
both burn and piercing injuries.
A postauricular abscess develops when mastoiditis
extends to invade the subperiosteal space. Mastoidec-
tomy is required; however, performing incision and
drainage in the offi ce can diminish the pain and infl am-
mation while arrangements are made for intravenous
antibiotics and surgery.
PATIENT SELECTION
All patients with the acute formation of a painful fl uctu-
ant mass in the ear require drainage. Although some
furuncles can be managed with warm compresses and
manual expression, other types of infection must be
incised to be drained. In the very early stages of infec-
tion of the ear there may not yet be a frank abscess.
High-dose systemic antibiotics can sometimes prevent
this early infection from developing into an abscess with
corresponding cartilage damage. These patients need
to be monitored daily for the infection to either resolve
or develop into an abscess to be drained.
PREOPERATIVE PLANNING
A complete history and focused examination that
includes otoscopy should be done before surgery. Indi-
viduals with a history of valvular heart disease should re -
ceive appropriate endocarditis prophylaxis. Antibiotic
prophylaxis for bacteremia should also be given to
immunocompromised patients, including those with
human immunodefi ciency virus infection or acquired
immunodefi ciency syndrome, patients with diabetes
mellitus, those receiving chemotherapy or steroids,
transplant patients, and alcoholics.
The size and cause of the furuncle/abscess will
dictate whether or what type of drainage procedure to
incorporate. Small abscesses that are complications of
ear piercing may require only a small drain or wick,
which can be removed in a few days. Larger abscesses,
usually those resulting from trauma to an extended
portion of the ear, will require a more elaborate drain-
age scheme.
For infections likely to cause cartilaginous destruc-
tion, the incision site should be planned so that it does
not hinder future reconstructive procedures. Generally,
reconstruction of the helical rim is accomplished
through an incision in either the helical or antihelical
fold in an attempt to conceal the scar.
SURGICAL TECHNIQUE
Furuncles
Injection of local anesthetic at several points lateral to
the abscess generally suffi ces for incision and drainage
of furuncles. Needle localization of the pocket before
incision is useful to confi rm the presence of pus.
Abscesses situated quite laterally may be incised with a
no. 15 blade. More medially situated abscesses may be
accessed more readily with a myringotomy blade.

1082
Section 12
Otology
Auricular Abscesses
The patient is positioned supine with the affected ear
up. The ear is prepared and draped. A regional ear
block is the preferred method. For smaller abscesses,
local injection of anesthetic can also be effective,
although a very cooperative patient is required because
manipulating the abscess is intensely painful. If suffi -
cient anesthesia is not achieved with a regional block,
local injection can be a useful adjunct. Injecting the
skin centrally overlying the abscess allows the anesthetic
to gradually diffuse through the skin/subcutaneous
tissue plane and provides excellent anesthesia to the
most sensitive portion of the abscess. An injection angle
parallel to the skin helps prevent injection into the
abscess cavity instead of subcutaneous tissue.
Once anesthesia has been obtained, the abscess is
incised with a no. 15 blade along the natural contour
of either the helical or antihelical fold. The pus is col-
lected and sent for culture. The abscess cavity must be
completely evacuated with all loculations eliminated. A
hemostat or other blunt-tipped instrument may be used
to probe the cavity and eliminate loculations. The car-
tilage is examined and any necrotic cartilage is débrided.
This should be done conservatively to minimize the
cartilage defect. It is possible that the cartilage will need
to be débrided again, but staged débridement helps
manage the size of the rim deformity. If extensive car-
tilage necrosis is noted, performing the procedure in
the operating room may be good judgment. Once the
cavity is adequately débrided, it is fl ushed with saline to
remove residual debris. The incision is not closed.
Depending on the size of the cavity, a drain or a small
catheter may be used for infusion of antibiotics.
Subperiosteal Abscesses
One percent lidocaine with epinephrine is injected in
curvilinear fashion approximately 1 cm posterior to the
postauricular sulcus. The incision used for drainage
should overlie the planned incision for mastoidectomy
(Fig. 107-6). A hemostat is then used to enter the abscess
cavity. Once the purulent exudate has been aspirated,
the wound is irrigated with saline. Defi nitive surgical
treatment should be scheduled to take place shortly
after incision and drainage of a subperiosteal abscess.
POSTOPERATIVE MANAGEMENT
Furuncles do not generally require follow-up, but the
patient should return if the pain or swelling worsens or
the condition is not healing within 1 week. Postopera-
tive management of other types of drained infections is
dependent on the extent of the infection. Patients with
signifi cant chondritis or a subperiosteal abscess should
be admitted for careful follow-up, administration of
antibiotics, and possible surgical management.
Patients with an auricular abscess should be
instructed that it may take several weeks for the infec-
tion to clear completely and that they are at risk for
recurrence during this time. If the infection recurs, it
should again be drained immediately with débridement
of necrotic tissue. If an auricular rim defect develops,
the patient should be referred for rim reconstruction.
Reconstruction will generally take place 6 to 9 months
after the infection has cleared to ensure that it has been
completely eliminated.
BIOPSY OF A MASS IN THE
EXTERNAL AUDITORY CANAL
Masses in the EAC are often asymptomatic and recog-
nized on routine screening otoscopic examination.
A
B
Figure 107-6. Postauricular abscess. A, The postauricular region
was erythematous and fl uctuant. B, Copious pus was cleared via a
small postauricular incision performed in the offi ce. A mastoidec-
tomy was done the following morning.

Chapter 107
Offi ce-Based Procedures in Otology 1083
However, they may be accompanied by hearing loss,
aural fullness, otalgia, or otorrhea. Masses in the EAC
can be benign or malignant (Table 107-1). The most
commonly encountered malignant masses in the EAC
are squamous cell, basal cell, and adenocystic carci-
noma. The fi rst step in planning the appropriate inter-
vention for treatment or removal of the growth is to
have an accurate diagnosis, which is often accomplished
by biopsy of the lesion. Some benign masses in the EAC
(i.e., osteomas, exostoses) can be diagnosed by their
classic appearance and location and do not require
intervention unless they are associated with conductive
hearing loss or interfere with the ability to clear the ear
of cerumen and squamous debris. Canal cholesteato-
mas can be addressed in the offi ce setting by careful
cleaning (see Chapter 110). Masses associated with a
recent onset of pain and otorrhea may represent infl am-
matory polyps associated with otitis externa. Topical
drops containing both a steroid and an antibiotic com-
ponent may resolve these masses without need for
biopsy. When a mass is suspected to be infl ammatory in
nature and topical therapy is used, close monitoring for
resolution of the mass is critical, with subsequent biopsy
of masses that fail to resolve.
More medially situated masses, such as polyps asso-
ciated with blockage of an attic retraction pocket, may
also be encountered. Removal of the bulk of these
polyps followed by steroid/antibiotic drops can resolve
the mass. Once the polyp has resolved, the attic may be
cleaned of cerumen and squamous debris, and if the
attic pocket is suffi ciently wide to allow complete visu-
alization and cleaning, it may be managed conserva-
tively. Even when a large cholesteatoma necessitating
surgical treatment is noted, addressing the polyp in the
offi ce setting may reduce infl ammation and allow a
smoother surgical procedure. In these situations the
polyp can be removed with cup forceps. Care should be
taken to avoid pulling on the lesion because it may be
associated with the ossicular chain.
It is also important to recognize the appearance of
malignant otitis externa, particularly in a patient with
diabetes. This severe infection is typically manifested by
granulation tissue at the bony-cartilaginous junction
and requires aggressive management with antibiotics.
Malignancies may masquerade as otitis externa, thereby
resulting in delays in diagnosis and treatment. Although
a diagnosis may be suggested by the physical appear-
ance of many of the remaining lesions, biopsy should
still be performed to confi rm the diagnosis. Finally, one
should be familiar with the pulsatile, fl eshy appearance
of glomus tumors. Large glomus tumors (Fig. 107-7)
may protrude into the ear canal, and biopsy of these
lesions in the offi ce is not wise because excessive bleed-
ing may result.
PREOPERATIVE PLANNING
Biopsy of any lesion can be a more anxiety-fi lled proce-
dure than other types of offi ce procedures because of
the fear associated with the diagnosis. If at all possible,
the biopsy should be done at the initial evaluation to
expedite a tissue diagnosis. It is important to commu-
nicate with the patient regarding the types of expected
diagnoses and the lag time until the pathology report
is available. Time should be taken to carefully answer
all the patient’s questions without painting an overly
dismal or overly optimistic picture.
SURGICAL TECHNIQUE
The patient is positioned supine with the affected ear
up. A four-quadrant canal block is the anesthetic
Table 107-1
MASSES IN THE EXTERNAL
EAR CANAL
Benign
Cholesteatoma
Eosinophilic granuloma
Exostosis
Fibrous dysplasia
Keratosis obturans
Neurofi broma
Osteoma
Paraganglioma/schwannoma
Stenosis
Temporomandibular joint herniation
Vascular lesions
Malignant
Adenocystic carcinoma
Basal cell carcinoma
Cerumen gland tumor
Malignant melanoma
Metastatic cancer
Soft tissue sarcoma
Squamous cell carcinoma
Figure 107-7. Pink, fl eshy mass in the right external auditory canal.
The mass was pulsating and noted to be protruding from the middle
ear, which was also fi lled with tumor. Further evaluation confi rmed
the diagnosis of a large glomus tympanicum tumor.

1084
Section 12
Otology
method of choice for this procedure. Once adequate
anesthesia has been achieved, microscopic cup forceps
can be used to remove the lesion. Pedunculated lesions
may easily be removed with Bellucci scissors. It is advis-
able to have vials of epinephrine available in the offi ce.
In the event that extensive bleeding is encountered,
small cotton balls soaked in epinephrine may be applied
to the biopsy site. Silver nitrate sticks may be broken
into small pieces and applied to the site with alligator
forceps, or a small amount of liquid silver nitrate may
be used on a small cotton-tipped swab.
POSTOPERATIVE MANAGEMENT
The patient should be seen in 1 week for evaluation of
the biopsy site, as well as to discuss the results of the
biopsy.
INTRATYMPANIC INJECTIONS
Intratympanic aminoglycoside or corticosteroid injec-
tion is an increasingly popular procedure performed
in the offi ce for the treatment of conditions such as
Meniere’s disease (MD) and sudden sensorineural
hearing loss (SSNHL). Intratympanic injections are
generally well tolerated with few side effects from the
procedure itself. The puncture sites are typically closed
within several weeks, and infections and persistent per-
forations are rare.15
It is well established that the main mode for chemi-
cals to gain access to the inner ear is through absorp-
tion at the round window. Obstruction at the round
window reduces absorption of the medication.16 Intra-
tympanic injection is the delivery technique preferred
by the authors. Other techniques for the delivery of
medications to the inner ear include injection of medi-
cation onto material such as Gelfoam placed directly on
the round window niche, insertion of pressure equaliza-
tion tubes with the self-administration of drops, wick
placement in the round window through a tympanos-
tomy tube, and microcatheter devices. Detailed infor-
mation on alternative techniques is discussed by Jackson
and Silverstein in their article, “Chemical Perfusion of
the Inner Ear.”17
Intratympanic Gentamicin
MD-associated vertigo can be incapacitating for the
patient, and a signifi cant number of patients do not
achieve control of vertigo with conservative measures
such as diuretic therapy and salt restriction. The use of
intratympanic aminoglycosides is a minimally invasive
approach to partial or total vestibular ablation. This
chemical vestibular ablation may obviate the need for
surgical management.
Gentamicin is the most commonly used aminogly-
coside for injection because it is associated with vestibu-
lar toxicity more than cochlear toxicity. Streptomycin is
similar to gentamicin in its predilection for the vestibu-
lar system but is less commonly used today because it
has been shown that intratympanic gentamicin (IT-
GENT) has a higher success rate in the control of
vertigo with a lower incidence of hearing loss.18 The
ototoxic effect of aminoglycosides is well established,
with the risk of permanent mild to profound hearing
loss increasing with increased use of the drug. Some
individuals have reportedly lost hearing with the fi rst
IT-GENT injection, whereas other individuals, surpris-
ingly enough, had improvement of their hearing loss
once their vestibular symptoms were controlled.4,19,20 A
review of the literature on intratympanic aminoglyco-
sides for MD reported control of vertigo in around 90%
of patients, but hearing loss also occurred in approxi-
mately 30%.21 Some hearing loss can be attributed to
the natural course of MD, which is characterized by
fl uctuations in hearing. Nonetheless, there is a signifi -
cant risk of profound hearing loss directly associated
with the use of IT-GENT that increases with higher
dosing. This risk is quoted to be as low as 3% when a
conservative dosing scheme is used and as high as 15%
in a more aggressive scheme. The current trend is
toward titrating treatment to control vertigo rather
than using a defi ned number of injections or total abla-
tion as an end point of treatment. This method is
believed by some to minimize the risk for hearing
loss.4,19,22 Before committing to IT-GENT, patients need
to be well informed of the risks of injection and take
into account how serviceable their current hearing is
and the impact that losing hearing would have on their
lives. Regardless of the risks to hearing, physicians and
patients now often favor a trial of IT-GENT for medi-
cally uncontrolled vertigo in an attempt to avoid inva-
sive surgery.
Intratympanic Dexamethasone
Various steroids are also injected into the ear, particu-
larly for the treatment of SSNHL. Classically, steroids
have been believed to exert an effect in both MD and
SSNHL through their anti-infl ammatory properties,
the assumption being that a viral or autoimmune-type
process is affecting the cochlea. However, this may not
actually be the case. It has recently been shown that
mice with autoimmune hearing dysfunction respond
equally well to aldosterone as they do to prednisolone,
thus suggesting that the mechanism behind the drug
effect may be through stimulation of a mineralocorti-
coid receptor.23
Regardless of the mechanism of action, the goal of
steroid therapy is to create the maximal effect through
achieving the highest possible concentration of steroid
in the perilymph while minimizing systemic side effects.
Studies of steroid concentrations in the perilymph of
guinea pigs have shown that it is possible to produce
much higher concentrations with intratympanic injec-
tion than via systemic routes.24,25 Although most studies
refer to intratympanic injection of steroids as a salvage
technique for the treatment of SSNHL and sudden
hearing loss associated with MD, some practitioners
are now considering it fi rst-line treatment because of
the relative ease of the procedure and avoidance of
systemic side effects.26

Chapter 107
Offi ce-Based Procedures in Otology 1085
PATIENT SELECTION
Intratympanic Gentamicin
IT-GENT is appropriate to consider in patients with MD
that is unresponsive to conservative measures. Such
measures include diuretics and salt and caffeine restric-
tion, which can adequately control symptoms in the
majority of patients. Conservative treatments should be
tried for at least 3 months before considering IT-GENT.
Use of IT-GENT has increased greatly over the past
decade but remains controversial, with some centers
relying more heavily on surgical procedures or includ-
ing a trial of histamine injections or the Meniett device
(Medtronic) before proceeding with an ablative proce-
dure. Although the procedure is relatively quick and
easy to perform, it carries a signifi cant risk of perma-
nent sensorineural hearing loss, as well as chronic dis-
equilibrium. Because MD is diagnosed by history,
careful discussion of the nature of the patient’s dizzy
spells must take place before any treatment. Migraine-
associated dizziness, benign paroxysmal positional
vertigo, superior semicircular canal dehiscence, and
other causes of episodic vertigo must be ruled out by
history, physical examination, or imaging. The vertigo
spells must occur with suffi cient frequency to be truly
disabling, and nonablative alternatives, both clinical
and surgical, must be extensively discussed. IT-GENT is
also sometimes useful in the setting of vestibular hypo-
function when a small amount of residual balance func-
tion in the affected ear impairs vestibular compensation.
Patients should be instructed to expect a period of sig-
nifi cant disequilibrium, usually for several days after the
injection. All patients are enrolled in vestibular reha-
bilitation to optimize vestibular compensation. Ideally,
the fi rst session takes place before the injection is
performed.
Usually, the affected ear is readily identifi ed on the
basis of unilateral aural symptoms, including fullness,
tinnitus, and hearing loss. If it is not clear which ear is
affected or if there are symptoms of bilateral MD, abla-
tive procedures much be approached with great caution
and only after nonablative treatments have been fully
explored. Patients with poor vision or impaired pro-
prioception (e.g., peripheral neuropathy) and older
patients may have an impaired capacity to compensate
for the resultant unilateral vestibular loss. The risk of
MD developing in the unaffected ear with possible oscil-
lopsia must be discussed with the patient. Gentamicin
is contraindicated in patients when the only hearing ear
is affected.
Intratympanic Dexamethasone
Currently, there is no well established set of criteria to
select patients who will benefi t most from intratympanic
dexamethasone (IT-DEX). A multicenter trial is under
way to help clarify questions concerning indications,
timing, frequency, type of steroid used, and concentra-
tion. The authors’ approach is to use oral steroids only
for mild SSNHL. For moderate or severe SSNHL, IT-
DEX is administered in conjunction with oral steroids.
Patients who cannot tolerate oral steroids (e.g., severe
diabetics) are considered for IT-DEX even with mild
SSNHL.
PREOPERATIVE PLANNING
For both IT-GENT and IT-DEX, pure-tone audiometry
should be performed before each injection. Vestibular
testing should be performed before proceeding with
IT-GENT. Signifi cant hypofunction in the unaffected
ear would represent a contraindication to ablation.
Some clinicians include electrocochleography because
an elevated summating potential to action potential
(SP/AP) may suggest hydrops; however, MD may be
present with a normal SP/AP ratio and a high ratio may
be present in the absence of symptoms.27 In MD, the
affected ear often has elevated thresholds on vestibular
evoked myogenic potential recordings.28 Patients with
SSNHL should undergo magnetic resonance imaging
with gadolinium enhancement to rule out a retro-
cochlear process because a fraction of acoustic neuro-
mas may be manifested in this manner. However,
because there is a benefi t to delivering the steroid early,
the fi rst injection is usually performed immediately on
detecting the sudden loss, with imaging studies sched-
uled to coincide with the 1-week follow-up visit.
SURGICAL APPROACH
The patient is positioned supine with the head at a 45-
degree angle, an appropriately sized aural speculum is
introduced into the ear canal, and an otoscopic exami-
nation is performed with removal of any obstructing
cerumen or debris from the canal and TM. Anesthesia
of the eardrum is then induced. If using phenol, the
applicator is touched to the anterosuperior and pos-
teroinferior TM (Fig. 107-8). A 25-gauge needle on a
tuberculin syringe loaded with the appropriate medica-
tion is used. The syringe is fi lled to 0.6 mL. Loading
more than this amount into the syringe can make it
awkward for the thumb of the injecting hand to reach
the plunger comfortably. The needle is bent to a 25-
degree angle at the hub and inserted via microscopic
visualization through an aural speculum. Bending the
needle helps prevent obstruction of the view of the TM
during the injection. The needle should be angled so
that the bevel will face superiorly as the middle ear is
entered. Because the drum is positioned with its infe-
rior aspect located more medially than its superior
aspect, it is easier to insert the bevel fully into the middle
ear and avoid spillage into the ear canal during the
injection. Spillage into the ear canal not only makes it
more diffi cult to determine whether an appropriate
volume has been injected but also makes it diffi cult to
visualize the rising air-fl uid level during the injection.
A puncture is made in the anterosuperior quadrant
within the area anesthetized by the phenol. This allows
air to exit the middle ear space and tends to ease the
aural fullness and discomfort associated with the injec-
tion. The needle is then inserted through a separate
puncture site in the posteroinferior TM and the

1086
Section 12
Otology
medication is injected. Typically, 0.4 mL can be injected
into the middle ear space. The authors use gentamicin
buffered with sodium bicarbonate at a fi nal concentra-
tion of 30 mg/mL and dexamethasone at a concentra-
tion of 10 mg/mL. However, it should be noted that
different concentrations and other types of steroids
have been used successfully. If it is diffi cult to stabilize
the needle as the TM is approached, steadying the
syringe with the thumb of the nondominant hand can
be helpful. The thumb of the injecting hand should be
in position on the plunger so that no adjustments are
required once the needle has been placed through the
TM. This prevents tearing at the myringotomy and
maintains a seal around the puncture site as the middle
ear is fi lled. The medication is slowly injected into the
middle ear space and the resultant air-fl uid level is
observed as it rises up to the anterosuperior puncture
site. Once the middle ear has been fi lled and effl ux of
medication into the ear canal is noted, the needle is
withdrawn and the patient remains supine with the
injected ear up for 25 to 30 minutes. The patient is
given tissues and a basin and is instructed to spit secre-
tions instead of swallowing them to minimize clearance
of the middle ear by the eustachian tube. The risk of
persistent perforation or infection has been very low
with this technique.
A
B
C
D
Figure 107-8. Intratympanic injection. A, Phenol, applicator, and loaded syringe. B, Application of phenol. A pinpoint myringotomy is
established anterosuperiorly to allow air to escape the middle ear during the injection. The medication is injected via a posteroinferior myrin-
gotomy. C, Bending the needle slightly allows better visualization during the injection. D, The injection is performed with the patient’s head
tilted 45 degrees away from the affected ear. Once the injection has been completed, the patient is asked to turn so that the injected ear faces
straight up. The patient maintains this position for 25 minutes.

Chapter 107
Offi ce-Based Procedures in Otology 1087
POSTOPERATIVE MANAGEMENT
Intratympanic Gentamicin
The patient is instructed to maintain dry ear precau-
tions until the follow-up visit at 3 weeks. Typically, by
this time the injection site will have healed and these
restrictions can be lifted. Some practitioners report that
more than 50% of patients experienced at least 2 years
of control of episodic vertigo with a single injection.20
Vestibular physical therapy is initiated and the patient
is seen in follow-up 3 weeks after the injection. An
audiogram is performed. If the patient reports persis-
tent severe attacks at the follow-up visit, a second injec-
tion is considered. Repeat injections may be performed,
separated by at least 3 to 4 weeks, in patients with per-
sistent symptoms. Treatment is discontinued when the
vertigo is controlled. This may occur despite persistent
vestibular function in the treated ear. Audiometry is
repeated before each injection and 2 months after the
last injection. Gentamicin may be associated with an
initial decline in hearing for up to 1 month after treat-
ment, but patients may subsequently regain some or all
of the hearing lost as a result of treatment.4 Diuretic
therapy and salt restriction are both maintained during
the course of treatment. Of the patients who achieve
control of vertigo, approximately 70% to 80% will con-
tinue to have their vertigo controlled at 2 years, and of
those who relapse, a second course of IT-GENT can
often achieve a sustained remission.19,20
Intratympanic Dexamethasone
The patient is instructed to maintain dry ear precau-
tions and is seen in follow-up within 1 week for a repeat
hearing test. If there has been an improvement but
the hearing has not returned to baseline, a second
injection is performed. Injections proceed on a weekly
basis until hearing returns to baseline or a plateau is
reached.
MYRINGOTOMY AND INSERTION
OF TUBES
Myringotomy, with or without insertion of pressure
equalization tubes, has become a mainstay in the man-
agement of recurrent otitis media, chronic otitis media
with effusion, complicated acute otitis media, or chronic
eustachian tube dysfunction. On occasion, tubes are
also used to provide access to the middle ear for deliv-
ery of medications, to provide ventilation of the middle
ear during hyperbaric oxygen therapy, or to enable use
of the Meniett device. Although children are most often
taken to the operating room for placement of tubes,
most adults can easily tolerate performance of the pro-
cedure in the offi ce under local anesthesia. Various
tubes should be available in the offi ce. Small tubes (i.e.,
tiny titans) are often useful for short-term aeration.
They may become clogged more easily, particularly with
viscous effusions. Midsize tubes (i.e., beveled Armstrong
tubes) typically remain in place for 6 to 9 months.
Patients with mucoid otitis media may benefi t from
short tubes with a wide internal diameter (i.e., Paparella
II tubes). In a cooperative patient with an adequately
sized ear canal, even the longer-lasting Goode T tubes
may be inserted in the offi ce setting, although they are
more commonly placed in the operating room. Myrin-
gotomy and tympanostomy tubes are both discussed
extensively in Chapter 112. This section focuses on
modifi cations of the procedure when performed in the
offi ce setting.
PATIENT SELECTION
All patients are examined carefully with an otologic
microscope. Pneumatic otoscopy should always be
included in the examination, because on occasion a
serous effusion may not be readily apparent even with
careful otomicroscopy. Tuning fork testing should also
be used to confi rm a conductive hearing loss. Even
when the history and physical examination clearly indi-
cate a chronic effusion, it is wise to formally test the
hearing before manipulating the TM for both medico-
legal and diagnostic purposes. Occasionally, chronic
effusions are associated with normal hearing, thus
leaving less reason to proceed with drainage. When
conductive loss is present, determining the degree of
loss can be helpful in ruling out additional pathology
involving the conductive apparatus.
As for all offi ce procedures, the surgeon must
determine whether the patient will be able to tolerate
the potential noise and discomfort without excess
motion. Unilateral effusion in adults merits careful
examination of the nasopharynx for adenoid hyper-
trophy or a mass lesion obstructing the orifi ce of the
eustachian tube. The patient is instructed regarding the
need for maintenance of a dry ear and the potential
risk of TM perforation. Patients who are avid swimmers
and disinclined to practice dry ear precautions may
prefer to live with an effusion or undergo fi tting with
custom plugs before the procedure. Insertion of pres-
sure equalization tubes may be diffi cult in patients with
severe middle ear atelectasis. However, a small titanium
tube can usually be inserted into the anteroinferior
quadrant and often provides signifi cant relief of aural
fullness. The decision regarding whether to perform
myringotomy alone versus proceeding with placement
of pressure equalization tubes hinges on the desired
duration of middle ear ventilation. A myringotomy may
close within days and is therefore used when very short-
term ventilation is needed. Serous effusions that occur
acutely in the setting of an upper respiratory infection
or after a fl ight will often resolve spontaneously, par-
ticularly if the patient is able to perform autoinsuffl a-
tion or a Valsalva maneuver with successful ventilation
of the middle ear space. A 3-day course of a nasal decon-
gestant such as oxymetazoline (Afrin), as well as a nasal
steroid spray, should be considered before myringot-
omy in these situations. Myringotomy should not be
used as fi rst-line therapy for uncomplicated acute otitis
media. However, when signifi cant otalgia is present,
myringotomy does provide symptomatic relief. Myrin-
gotomy with tube insertion is indicated when acute