Atlas-of-Neurosurgical-Techniques-Spine-and-Peripheral-Nerves

30
Occipitocervical Junction: Pathology of the Occipitocervical Junction
NPC, nasopharyngeal
carcinoma.
(Adapted from Sekhar LN,Schramm VL.Tumors of the Cranial Base: Diagnosis and Treatment.
Mount
Kisco. NY: Futura;
1987:26.)
nerves may also be affected. Histologically these tumors
consist of thin-walled blood vessels between cords of ep-
ithelioid cells and rarely metastasize along CSFpathways.
Their natural history is relatively benign, with survival peri-
ods of up to 20 years after diagnosis, but recurrence after
excisionis seen as early as 3 years.
Table 3-2 summarizes the common primary tumors of
the occipitocervicaljunction.
.
Summary and Conclusion
A thorough familiarity of both the normal and the
pathoanatomyofoccipitocervicaljunctionlesionsaswellas
an understandingof the clinicaland biologicalfeatures of
References
1.
VanGilder
JC, Menezes
AH, Dolan DK. The craniovertebral
junction
and its abnormalities.
Mount Kisco, NY: Futura; 1987
2.
McMinn RMH. Head and Neck. In: Last's Anatomy. 8th ed. New York:
Churchill Livingstone;
1990:544-546
3.
Dickman
CA, Crawford
NR, Brantley
AGU. In vitro cervical
spine bio-
mechanical
testing. In: Spetzler
RF,ed. BNIQuarterly
1993;9:4
4.
Buckingham
MJ,Tew JM, WiotJG. The diagnosis
and surgical manage-
ment
of craniocervical
junction
tumors.
In: Camins MB, O'Leary PF,
eds. Disorders
of the Cervical
Spine. Baltimore,
MD: Williams
and
Wilkins;
1992
5.
Johnson
MH, Smoker
WR. Lesions of the craniovertebral
junction.
Neuroimaging
Clin N Am 1994;4:599-617
neoplasms in this region is a prerequisite for proper surgical
management. The wide variety of lesions that occur in this
area are mostly benign but some behave in a malignant
fashion. Modern neuroradiological diagnostic techniques
such as high-resolution MRIand CThave greatly improved
the preoperative diagnostic accuracy of these lesions. This
has enabled more precise preoperative planning and the in-
volvement of surgeons with specific skills and techniques.
Further advancements of imaging diagnosis and intraopera-
tive image guidance will improve the safety of operating
these difficult lesions.
Minimallyinvasivetechniques may also become more use-
ful in the management of these tumors, and contributions
from gene therapy and molecular biology may ultimately al-
low for earlier detection and alternative means of treatment.
6.
Menezes
AH, Traynelis
V.Tumors
of the craniovertebral
junction.
In:
Youmans JR, ed. Neurological
Surgery:
A Comprehensive
Reference
Guide to the Diagnosis
and Management
of Neurosurgical
Problems.
Vol 4. 4th ed. Philadelphia:
WB Saunders;
1996:ch 140
7.
Sekhar
LN, Schramm
VL.Tumors
of the Cranial
Base: Diagnosis
and
Treatment.
Mount Kisco, NY: Futura;
1987:26
8.
Segal DH, Sundaresan,
N. Primary
Osseous and metastatic
neoplasms
of bone at the craniovertebral
junction.
In: Dickman,
CA et ai, eds.
Surgery of the Craniovertebral
Junction.
New York: Thieme;
1998
Table 3-2
Summary
of the Common
Primary Tumors at Occipitocervical
Junction
Tumor
Frequency
M:F Ratio
Age at Onset
X-ray Appearance
Survival
Chordoma
1%of all intracranial
2:1
40
Erosion of bone
30-50% 5-year
tumors
tumor
calcification
Chondrosarcoma
6%of all skull base
1:1
30-40
Erosion of bone
40-60% 5-year
tumors
calcification
Nasopharyngeal
25%of all NPCs
3:1
45
Destruction of bone
20-40% 5-year;
carcinoma
affect skull base
variable, depending
on underlying disease
Meningioma
8%of all intracranial
1:3
20-60
Hyperostosis
Lessthan normal
tumors
population at 15 years
Glomus jugulare
1%of all intracranial
1:6
55
Destruction of bone
93% 10-year
tumors

4
Traumaofthe OccipitocervicalJunction*
Curtis
A. Dickman
. Isolated Ligamentous
Injuries
Occipitoatlantal Dislocations
Transverse Ligament Injuries
Rotatory C1-C2 Dislocations
. Isolated Fractures
AtlasFractures
Odontoid Fractures
It is useful to classify injuries of the occipitocervical
junctionas isolated ligamentous injuries, isolated bone
fractures,or mixed ligamentous and bony injuries. The
extentofthe injuriesto the bones and ligamentsis impor-
tantforpredicting the results of treatment. In this chapter,
eachcategoryofinjuryis consideredseparately.Thisisan
importantconceptual framework because ligaments are in-
capableofrepair when disrupted.t-3 Therefore, ligamentous
injuriesusually require surgery to restore spinal stability.
Bonefracturescan usually heal as long as the bones can be
reducedand immobilized
satisfactorily.
However, when the
bonesare fractured extensively
and comminuted
widely or
whenfractures are accompanied by disrupted ligaments,
thennonoperative treatments are likely to fail and surgery
isrequiredto restore permanent spinal stability. This chap-
ter focuses on the clinical
presentation,
diagnosis,
treat-
ment,and outcome
of injuries
to the articular
and bony
structuresof the occipitocervical junction.
. IsolatedLigamentous Injuries
Isolatedligamentous injuries include occipitoatlantal dislo-
cations,transverse ligament
disruptions,
and rotatory
C1-(2dislocations.Occipitoatlantal dislocations and trans-
verseligamentinjuriesare highlyunstable.Theseinjuries
requiresurgical treatment
because
the ligaments
are
avulsedand are incapable of healing. Rotatory (1-(2
dislo-
cations,however,are different and less severe injuries that
rarely require surgery.
Hangman's Fractures
Combination Atlas-Axis Fractures
.
Injuries Likelyto FailNonoperative Treatment
. Summary
Occipitoatlantal Dislocations
Occipitoatlantal dislocations are usually caused by high-
velocity accidents; they are highly unstable and stretch,
compress, and distort the spinal cord.4-tOThey tend to occur
in conjunction with severe neurological injuries or to cause
immediate death (Table 4-1 ).Instability causes mechanical
injury by distraction or direct compression of the spinal
cord, brain stem, and cranial nerves. Ischemic or vascular
injury can occur if the vertebral arteries are stretched. Ex-
tensive instability requires immediate rigid spinal fixation
to immobilize the ligamentous injury. Occipitoatlantal dis-
locations should be immediately fixated with a halo brace.
Cervical collars (such as a Philadelphia collar) are con-
traindicated because they reproduce the distractive mecha-
nism ofinjury and can cause additional severe neurological
injury. Cervicaltraction is likewise contraindicated because
it also reproduces the mechanism of injury. Even a halo
brace allows significant movement to occur in this form of
injury; therefore, urgent operative stabilization is advocated
if neurological function can be salvaged. Treatment consists
of occipitocervical fixation and fusion.
Occipitoatlantal dislocations can be difficult to diagnose
using plain radiographs. Several criteria have been used
(Fig.4-1). Most patients with complete spinal cord injuries
from occipitoatlantal dislocations have obvious distraction
of the occipital condyles from the C1 lateral masses
(Fig. 4-2). However, if some spinal cord function is pre-
served, the alignment or gap between the occipital condyles
and (1 lateral masses is usually not obvious on plain radio-
graphs because cervical muscle spasm helps to maintain
'Thischapteris reprinted with permission from Dickman CA, Greene KA, Sonntag VKH. Traumatic injuries of the crainiovertebral junction.
In:DickmanCA,SpetzlerRF,SonntagVKH(eds.).Surgeryof the craniovertebraljunction. New York:Thieme, 1988:175-196.
31

32
Occipitocervical Junction: Pathology of the Occipitocervical Junction
Table 4-1
Craniovertebral Junction Trauma: Spinal Cord Injury and Mortality
RatesO
.Obtained from 1915 total cervical spine injuries.
residualalignment. Despitethe subtle radiographicclues,
patients with incomplete neurological injuries are still
highly unstable and can deteriorate neurologically. There-
fore, it is important to obtain a proper diagnosis and to
immobilize the head satisfactorily (Le., halo brace) until
definitive internal stabilization can be performed. Most
patients with occipitoatlantal
dislocation have a severe
head injury that can also obscure the clinical diagnosis.
Plain radiographic diagnostic clues of occipitoatlantal
dislocation include severe swelling of the prevertebral soft
tissues, widening of the dens-basion distance, and a gap
between the occipital condyles and upper surfaces of the C1
lateral masses. landmarks from the skull base and upper
cervical spine can be measured (Fig.4-1 ),but they are not
sensitive or specific enough to detect all occipitoatlantal
dislocations (Table4-2).
Avarietyof plain radiographicmeasurementtechniques
may be used to detect dislocationsof the occipitocervical
junction (Fig.4-1 ).These methods assess the relationships
between the skull base and cervical spine on lateral radio-
graphs. Wackenheim's clivalline, the dens-basion distance,
the Dublinmethod, the X-line method, and Power's method
can be applied.7.11-19
Wackenheim's line extends caudally along the posterior
surface of the clivus.19This line should be tangential to
the posterior tip of the dens. If the occiput is displaced
anteriorly, the line will intersect the dens. Ifthe occiput is
distracted
or displaced
posteriorly,
the
line will be
separated
from the tip of the dens. Traditionally, this
technique has been used to assess basilar invagination, but
it can provide ageneral assessment for dislocation.I1.12.19
Power's ratio assesses the relationship of two lines: the
distance between the basion (B) and the posterior arch of the
atlas (C)and between the opisthion (0) and the anterior arch
of the atlas (A).17Innormal individuals, BC/OAaverages0.77.
Aratio> 1.0isa fairlyreliable diagnostic indicator of an an-
terior dislocation. This technique cannot be applied to chil-
dren or individuals with congenital occipitocervical anom-
alies, and it can have false negatives with longitudinal and
posterior dislocations. lee's X-line method is similar to
Power'sratiobut useslandmarksofC2(insteadofC)in rela-
tion to the basion and opisthion asreferences.7
Figure 4-1
Lateralradiographiccriteriaforthe
diagnosis
of
atlanto-occipital
dislocations.
(A)
Wackenheim's
line.
(8)
Power's
ratio.
(C) Dens-basion
distance. (D) Dublin's method.
(From Dickman CA, Douglas RA, Sonntag VKR.
Occipitocervical fusion: posterior stabilization of
the craniovertebral
junction
and upper cervical
spine. BNIQ 1990;6:2-14.
Used with permission.)
Spinal Cord Injury # (%)
Mortality # (%)
Total Injuries #
Occipitoatlantal dislocation
17(100)
14(82)
17
Transverse ligament disruption
2 (10)
1 (5)
20
Rotatory atlantoaxial dislocations
0
0
5
Isolated atlas fractures
2 (3)
1 (1.3)
78
Isolated axisfractures
19 (6)
18 (6)
298
Combination atlas-axis fractures
8 (14)
3(5)
57
,/,..
-
II
.
,/..
II

A
~
B
Figure4-2
(A)lateral radiographs of an occipitoatlantal
dislocation. Severe prevertebral soft tissue swelling is present. The occipital condyles are
distractedlongitudinallyand displaced anteriorly from the Cllateral
masses. (B) Open-mouth
views demonstrate
wide separation
of the occipital
condyles(open arrow) from the upper
surface
of C1 (closed
arrow).
TheWholeydens-basion
method
measures
the interval
betweenthe basion and the tip of the dens in a neutral po-
sition.9.12.13.18
In adults, this distance
averages
9 mm but
variesconsiderably.Anymotion between these landmarks
ondynamicradiographs is abnormaJ.7 A distance>
15 mm
inadultsor 12mm in children is abnormaJ.7
4
Trauma of the Occipitocervical Junction
33
Dublin's method measures the distance from the posterior
cortex of the ramus of the mandible to the anterior portion
of (I and (2.14These measurements
must be obtained on
72 cm radiographs with the patient's mouth closed. This
is the least reliable method of diagnosis. Normal distances
to C1 range from 2 to 5 mm; normal distances to (2 range
Table4-2
Techniquesfor the PlainRadiographicDiagnosisof Occipitoatlantal Dislocations
Measurement Technique
Case
TypesofDislocation
Wackenheim's Line
Dens-Basion Distance
Power's Method
Dublin's Method
1
longitudinal
+
+
-
0
2
longitudinal
+
+
+
0
3
Anterior
0
+
+
+
4
Posterior
+
+
5
longitudinal
+
+
+
+
6
Anteriorand longitudinal
0
+
+
0
7
Posterior
+
8
Anteriorand longitudinal
+
+
+
+
9
Rotatory
10
longitudinal
+
+
+
+
11
Rotatory
12
Posteriorand longitudinal
+
+
0
0
13
longitudinal
+
+
+
14
Rotatory
Total
9
10
7
4
+,positiveforoccipitoatlantal dislocation; -, negative for occipitoatlantal dislocation. (From DickmanCA,Papadopoulos SM,Sonntag
VK,etal.Traumaticoccipitoatlantal dislocations. JSpinal Disord 1993;6:300-313. Used with permission.)

34
Occipitocervical Junction: Pathology of the Occipitocervical Junction
from 9 to 12 mm. This method is invalid if a mandible
fracture is present, and it is unreliable with posterior
dislocations.7
Plain radiographic measurement techniques are nonspe-
cificand insensitive for diagnosing dislocations for several
reasons. True lateral films are needed and it can be difficult
to reliably identify
the
appropriate
landmarks
(e.g.,
opisthion, basion) reliably.The mastoid processes and mas-
toid air cells often obscure the visualization of the occipi-
toatlantal articular surfaces.7 At best, plain radiographic
measurements detect 50 to 75%of dislocations.7 Wacken-
heim's cIivalline and the dens-basion distance are the most
sensitive measures for detection of dislocations on plain
radiographs (Table 4-2). However, only 71%of the cases
were detected using plain radiographic studies.
Plain radiographic methods of assessing the alignment of
the occipitocervical junction have additional limitations.
Each method is applicable only to specific subtypes of
dislocations.
None of these
methods
reliably detects
rotational dislocations or minimally displaced subluxations.
These techniques are invalid ifatlas or axis fractures are pre-
sent, or if the clivus,atlas, or axis is malformed.7-IO.13.16.19.20
All suspected occipitoatIantal dislocation injuries should
be evaluated rapidly to confirm the diagnosis. Repeat lateral
cervical radiographs often display a change in alignment
or distraction of the occipital condyles, especially if a cervi-
cal collar, which causes distraction (Fig. 4-3), has been
applied. Thin-section
computed
tomography (CT) with
three-dimensional
reconstruction can be very helpful for
demonstrating
a dislocated,
rotated
occipital condyle.
Magnetic resonance imaging (MRI)is less useful because it
does not clearly depict the osseous anatomy. However, it
can confirm the extensive ligament and soft tissue injury in
the region and assess the integrity of the spinal cord and
brain stem.
Treatment of occipitoatIantal dislocations is based upon
the extraordinary instability of the ligament avulsions, the
Figure 4-3
Lateral cervical radiographs
of an occipitoatlantal
dislo-
cation.
This patient
arrived in the emergency
department
with a
Philadelphia collar that was applied at the scene of the accident (right).
The collar reproduced
the distractive
mechanism
of injury and can
cause decompensation
of this highly unstable injury. (Left) The relative
position of the occipital condyles and (1 was immediately
improved
by removing the cervical collar and immobilizing the head in a neutral
position on a spine board.
risk of delayed neurological injury, and the inability ofliga-
ment disruptions to spontaneously heal satisfactorily.
Attempted realignment of dislocations may cause injury
and
should
be instituted
cautiously
and only under
radiographic or fluoroscopic guidance. Axial loading or
gentle compression of the head may reduce distractions.
Some authors advocate axial traction with low weights
to attempt realignment of dislocations.17.18.21-23
However,
these
maneuvers
are dangerous.
Cervical traction or
cervical collars reproduce the distractive mechanism of
injury, can precipitate
additional
neurological
injury,
and are contraindicated. Surgery provides a means to obtain
a controlled
realignment
and
to achieve
permanent
stabilization.
Ahalo brace alone is inadequate to maintain permanent
alignment of the occipitocervical junction after an occipi-~
toatlantal dislocation. Acute internal fixation is also needed.f'
However,the halo brace provides a temporary, supplemen-i"
tal means of external stabilization until internal fixation1~'
and fusion are attained.
.
An aggressiveoperative treatment strategy is justifiedI'
if patients
have
potentially
salvageable
neurological
function. Normal patients
or patients
with incomplete
neurological injuries should be treated urgently because
they have a high risk of loss of neurological function due
to the extensive instability. Rotational, translational, and
distractive
injuries are equally unstable. The extreme .
acute instability
and the inadequacy
of nonoperative
therapy for ligamentous injuries justify the need for early .
internal fixation. A posterior occipitocervical arthrodesis
should be performed for internal fixation to preserve func-
tion and to permit the maximal recovery of neurological
function.
Transverse Ligament Injuries
Disruption of the transverse atlantal ligament results in
anterior C1-C2 subluxation.24.25Anterior C1-C2 subluxa-
tion, however, can also occur without a disrupted trans-
verse ligament, as with os odontoideum or odontoid frac-
tures. Adisrupted transverse ligament is manifested bya
widened atlantodental interval (ADI)on lateral cervical ra-
diographs when the neck is flexed. Wh~n the head and
neck are in a neutral or extended positfon, the ADImay
appear normal. If the ADIexceeds 3 mm in an adult (or 5
mm in children) a transverse ligament disruption should
be suspected. MRIwith gradient-echo
sequences can be
used to image the ligament directly and to assess its
anatomical integrity.26Disruption of the ligament appears
as high signal intensity
within
the ligament,
loss of
anatomical continuity, and blood at the insertion site of
the ligament.
Injuries involvingthe transverse atIantalligament can be
classified into two distinct categories; each subtype has a
separate
prognosis and requires different treatments.25
Type Iinjuries are disruptions of the substance of the trans-
verse atlantal ligament. Type II injuries are fractures or
avulsions that detach the bony tubercle for insertion of the

4
Traumaof the OccipitocervicalJunction
35
Figure4-4
Classification of injuries to the transverse atlantalligament.
(A, B) Type I injuries disrupt the ligament
substance in its mid portion
(type
IA)orat its periosteal insertion
(type IB). Type II injuries
disconnect
the tubercle
for insertion
of the transverse
ligament
from the (1 lateral mass
involvingacomminuted C1 mass (type IIA) or avulsing the tubercle
from an intact lateral mass (type liB). (With permission
of Barrow Neurological
Institute.)
transverseligament on the Cllateral mass (Fig.4-4). These
twotypesofinjuriescan be differentiated using a combina-
tionof MRI to assessthe soft tissue pathology (Le., the
anatomyof the ligament) in conjunction with thin-section
IT to assess the osseous
pathology
(Figs. 4-5
and 4-6).
Althoughplain radiographs
are
useful
to screen
for a
potentialabnormality,plain radiographic indices are unreli-
ablefor predicting the status of the transverse atlantal
ligamentbecausethey do not directly demonstrate
its
anatomy(Fig.4-7).
TypeI injuries are incapable of healing with an orthosis
becausethe ligamentous substance is incapable of repair.
Theseinjuries should be treated with early surgery to fix-
ate(1-(2
internally. Type IIinjuries detach the tubercle
and render the transverse
ligament
physiologically
incompetenteven though the ligamentous substance is
nottorn.
TypeIIinjuries havea 74%chance of healing satisfactorily
whentreated with a rigid cervical orthosis (halo brace)
(Fig.4-8). Surgeryis reserved for type IIinjuries that have
nonunionwith persistent instability after 3 to 4 months
ofimmobilization.TypeIIinjuries have a 26%rate of failure
ofimmobilization; therefore, close monitoring is needed
to detect patients who will
require delayed operative
intervention.
Rotatory
C1-C2 Dislocations
Rotatory atlantoaxial dislocations primarily occur in young
childrenandadolescents(Fig.4-3 ).3Childrenoftenpresent
with their head fixed in a "cocked-robin" position. Open-
mouth radiographsdemonstrate asymmetryof the lateral
masses of (1-C2 on open-mouth
views. However, CT is
much more helpful for clearl1 defining the injured anatomy
and to exclude a fracture. Rotation of C1on C2of more than
470in the axial plane is pathognomonic of rotatory C1-C2
dislocation. Two-dimensional and three-dimensional recon-
structed CTimages are useful for demonstrating the abnor-
mality (Fig. 4-9). Treatment consists of reduction with
halter traction or Gardner-Wells tongs and subsequent
immobilizationwith acervicalcollarfor10to 12weeks.
MRIstudiesare recommendedto ruleout an associated
disruption of the transverse atlantalligament.
Ifthe trans-
verse ligament is disrupted, internal fixation is needed even
if the rotatory dislocation is reducible. Ifthe transverse liga-
ment is normal, external reduction and immobilization rep-
resent adequate treatment. The majority of these injuries
can be managed nonoperatively with reduction and exter-
nal immobilization. Surgery is reserved for patients with ir-
reducible or recurrent subluxations, or when the transverse
ligament is disrupted (Fig.4-10).

36
Occipitocervical Junction: Pathology of the Occipitocervical Junction
I
B
c
E
Figure 4-5
(A) The normal
transverse
atlantal
ligament
(TL)
appears on axial gradient echo magnetic
resonance imaging
(MRI)
studies (TR 733 MS, TE 18 MS, flip angle 20 degrees, slice 3 mm) as
a homogeneous,
continuous,
thick, low-signal
intensity
structure
that extends between
the medial portions
of the lateral masses of
(1.
The ligament
is contrasted
by high-signal
intensity
on both
sides-anteriorly
by synovium
and posteriorly
by cerebrospinal
fluid. (8) Postmortem
specimen
of (1
demonstrating
the struc-
ture of the normal transverse atlantalligament.
(C) Autopsy speci-
men demonstrating
a midsubstance
disruption
of the transverse
atlantalligament
(type IA injury).
(D. E) MRI studies of type IB in-
juries in which the transverse
ligament
is torn from
its periosteal
insertion
on the (1
tubercle.
The disrupted
ligaments
demon-
strate high-signal
intensity within
the ligament,
loss of anatomical
continuity,
and blood at the insertion
of the ligament
(arrows).

A
LiIi
'!._ ."!
_ _
. 8
Figure4-6
Type II injuries detach the tubercle
for the transverse ligament
from the C11ateral mass. (A) Computed
tomography
(CT) scan of a type
IIinjurydemonstrates a comminuted
fracture
of the C1 lateral mass, which
renders the transverse
ligament
physiologically
incompetent.
(B) The
magneticresonanceimage that corresponds to the CT demonstrates
that the soft tissue structure
of the transverse
ligament
is preserved.
ISJ A
14
13
12
TOIII
11
C1l1t8ra1 10
_9
Di.pacement
8
(mm)
7
6
S
4
3
2
1
o
o =Atlas
Fracture
o
= Odontoid
Fracture
ICI = C1.c2
ComblnaUon
Fractura
... = No Fractures
of CI or C2
8
00
n"
__
_ _ _ _
_g;x;m..
_ _
_ _ _ __
CXX>
0
o
00
o
,sJ B
14
13
12
IuIrnai
11
_110_
9
(m)
8
7
6
S
4
3
2
I
o
o =Atlas Fracture
o =Odontoid
Fracture
D =CI..c2
Combination
Fracture
... =No Fractura.
of CI or C2
o
0
...
...
00
M.
ICI
00
...
...
0
0000
0
__h.
_
___
_ ___ JX:D...
_ __
_ ___
00
a::IXX)
o
Mldsubstance
LIg.menl
Disruptions
(IA)
Osteoperiosteal
Ligament
Disruptions
(IB)
Comminuted
CI Lateral
MassFractures
(IIA)
Tubercle
Avulslons
(liB)
4
Traumaof the OccipitocervicalJunction
37
..
Figure
4-7
Correlation
of
plain
radiographic
findings,
with
the
pathoanatomy
of the injury patterns
to the bones and ligaments,
as visual-
ized using computed
tomography
and magnetic
resonance
imaging.
(A)
The type of ligamentous
injury
in relation
to the total
amount
of displace.
ment of the C1 lateral masses on open. mouth
views of C1-C2.
If a 7.0 mm
criterion
is used to presume transverse
ligament
disruption,
more than half
of the unstable
atlas fractures
would
have been missed. Spence's 7.0 mm
rule does not accurately
predict
the status of the transverse
atlantalliga.
ment after
an atlas fracture.
(B) The type of ligament
and bone injury
in
relation
to the maximal
atlantodental
interval
on preoperative
lateral cervi-
cal radiographs.
If a 3.0 mm cutoff
is used to presume
a disrupted
trans-
verse atlantalligament.
10 of the 39 injuries (26%) would not have been de-
tected.
Less than 10% of the type
I injuries,
but almost 40% of the type
II
injuries, would have been missed. (With permission from Barrow Neurologi-
callnstitute.)
CXX>
0
........
Don.........""...
00
...
I
I
I
IIldsubstance
Osteoperiosteal
Comminuted
Tubercle
LJgament
Ligament
C1 Lateral
Avulslons
Disruption
Disruptions
Mass Fractures
(liB)
(IA)
(IB)
(IIA)

38
Occipitocervical Junction: Pathology of the Occipitocervical Junction
A
B
Figure 4-8
(A) This patient sustained a type IIinjury involving the transverse ligament with extensive crush and comminution
of the left C1 lateral
mass. (8) After 12 weeks of immobilization in a halo brace. the fractures healed with an osseous union and normal motion was restored to C1-C2
without evidence of instability. The tubercle for insertion of the transverse ligament was completely incorporated into the adjacent bone.
Atlantoaxial Rotary Dislocation
X-ray
CT
MRI
Normal
transverse
ligament
Figure 4-9
Three-dimensional
computed
tomographic
reconstruction
of a C1-C2 rotatory dislocation injury.
Transverse
ligament
disruption
External
reduction
I
Irreducible
I
I
Reducible
I
ORIF
External
immobilization
.
IsolatedFractures
Isolated fractures of the atlas or the axis or combined
atlantoaxial fractures are common injuries. Fracturesof
the first two cervical vertebrae account for one third of
ORIF
Figure 4-1 0
Treatment algorithm for C1-C2 rota-
tory
dislocations.
The
majority
of patients
are
treated successfully with reduction
and immobiliza-
tion without surgery. ORIF.open reduction and inter-
nal fixation. (From Sonntag VKH.Dickman CA.Treat-
ment of Upper Cervical Spine Injuries. AANS; 1992.
With permission of the American Association of Neu-
rological Surgeons.)
all cervical spine fractures. A substantial
proportion of
fractures involve both the atlas and the axis (Le..combina-
tion atlas-axis fractures) (Tables4-1 and 4-3).
Isolated fractures usually heal nonoperatively as long as
the fractures are nondisplaced
or minimally displaced
~""
~:,""'~;::,.
. ~
-
:
, ,-,-~===
_.-==:c=;-.",_
__

'Dataaccumulatedduring an 18-year period at the Barrow Neurological Institute.
(Table4-3). The amount of fracture angulation and dis-
placementis a reflection of the extent of the associated
spinaligamentousinjury. Minimally or moderately dis-
placedfracturescan usually be treated successfully with a
cervicalorthosis (Table 4-4). In general, the type of or-
thoticusedfor a particular cervical fracture depends on
theextentof injury of the bone and Iigaments,27-3oSoft
collarsandPhiladelphia collars are orthoses that restrict
cervicalmotionminimally; these are usually appropriate
for nondisplaced fractures.
The
sternal-occipital-
mandibular-immobilization
(SOMI) brace
and the four-
posterbracehaveintermediate immobilization character-
istics and
they
adequately
immobilize
minimally
displacedfractures. A cervicothoracic
orthosis,
Minerva
brace,or halobraceis used for moderately or widely dis-
placedfractures.
AtlasFractures
Awidevariety of atlas fracture
patterns
exist.24.25.31-33Al-
mostanypart of the C1 ring can be affected (Fig. 4-11).
Most(1 fractures
heal satisfactorily
with
an orthosis,
exceptwhen the anatomical continuity of the transverse
ligamentis disrupted (Figs.4-4 through 4-7) or when an
extensivelycomminutedC1lateral mass disconnects the tu-
bercleandrendersthe transverse ligament physiologically
incompetent(Figs.4-4, 4-11, and 4_12).24.25Isolated atlas
fracturesare best evaluated using a combination of plain
Table4-4 OrthosesforCervicalFractures
Softcollar
Philadelphia-type
collar
SOMIbrace
Four-poster
brace
Minimally
displaced
fractures
Cervicothoracicbrace
Halo brace
Nondisplacedfractures
Moderately or widely
displacedfractures
radiographs, CT,and MRI.Ifthe transverse atlantalligament
is normal, nonoperative therapy with an orthosis is recom-
mended. However, if the transverse atlantal ligament is
disrupted, C1-C2 fusion is required (Fig.4-13).
Mildly or nondisplaced atlas fractures are treated with a
SOMIbrace or a Philadelphia collar. Ahalo brace is used for
widely displaced fractures. Ifthe fracture is comminuted and
involves the lateral mass of C1and disconnects the tubercle
for insertion of the transverse ligament, rendering it incom-
petent, then a halo brace is recommended. Atlantoaxial sta-
bility and functional ligament integrity can be restored as
long as the tubercle unites with the C1 lateral mass. This
union is best achieved with a halo brace. However,this type
of C1injury has a 26%chance of nonunion when treated with
an orthosis.25Forthis injury type, we advocate initial treat-
ment with a hale brace and frequent follow-up. Latesurgery
may be required if healing is not adequate.
Axis Fractures
Axisfractures of the second cervical vertebra can be charac-
terized as odontoid fractures, hangman's fractures, or mis-
cellaneous C2fractures (Table 4-3, Fig.4_14).31.34-38
Odon-
toid fractures are further subclassified into type I,II,and III
injuries. Type Ifractures are rare, involve only the tip of the
dens, and can be treated adequately with a semirigid ortho-
sis. Type IIfractures occur across the neck of the dens and
account for two thirds of all odontoid fractures. Type III
fractures extend from the base of the dens into the C2body
and account for one third of all odontoid fractures. Bone
and any associated ligament injuries are best evaluated us-
ing thin-section CTand MRI.
OdontoidFractures
The criteria used for treatment of odontoid fractures are
based on the amount of bone displacement and the extent
4
Trauma of the Occipitocervical
Junction
39
Table4-3
Treatment
and Outcome
among
C2 Fractures
and C1-C2
Combination
Fracturesa
Fracture Type
Type I
Type II
Type III
Odontoid
Odontoid
Odontoid
Hangman's
Misc.C2
IsolatedC2fracturestotal (N)
2
134
86
80
70
InitialTreatment
(a)externalorthosis
2
112
86
80
70
(b)earlysurgery
0
22
0
0
0
Failuresof nonoperativetreatment
0
28
2
3
5
Totalnumberrequiringsurgery
0
50 (37%)
2 (2%)
3(4%)
5(7%)
(1-(2 combinationfracturestotal (N)
0
23
10
11
13
InitialTreatment
(a)externalorthosis
0
16
10
11
13
(b)earlysurgery
0
7
0
0
0
Failuresofnonoperativetreatment
0
3
0
3
0
Totalnumberrequiringsurgery
0
10(43%)
0(0%)
3(27%)
0(0%)

40
Occipitocervical Junction: Pathology of the Occipitocervical Junction
G
Figure 4-11
A variety of types of atlas fractures exist. (A) The four-part
ring or burst fracture is classically referred to as a Jefferson fracture.
(8) The
comminuted lateral massfracture isextremely common. It creates(1-(2
instability by rendering the transverse ligament incompetent becauseit
detaches the tubercle
for insertion
of the transverse ligament.
More stable patterns of injury include (C) the unilateral
ring fracture.
(D) linear lateral
mass fracture,
(E) posterior
ring fracture,
(F) anterior
arch fracture,
or (G) contralateral
ring fracture.
The major determinant
of stability
of these
injuries is whether
the transverse atlantalligament
is anatomically
and physiologically
intact.
(With permission
from Barrow Neurological
Institute.)
---
--
~-~
-----

Isolated Atlas Fracture
X-ray
CT
MRI
4
Traumaof the OccipitocervicalJunction
41
Figure 4-12
This comminuted C1 lateral massfracture has detached the
tubercle that anchors the transverseligament, which createsatlantoaxial insta-
bility (type IItransverse ligament injury). The C1 lateral masswas displaced
laterally 9 mm. Despite treatment with a halo bracefor 16weeks,a nonunion
developed with persistent C1-(2 instability that required internal fixation.
(With permissionfrom BarrowNeurological Institute.)
ORIF
I
Figure 4-13
Algorithm
for treatment of
atlas fractures. The most important factors
to consider for treatment are the amount of
bone comminution,
the width
of bone
displacement, and whether the transverse
ligament is incompetent. If the transverse
ligament
substance is disrupted
(type I
transverse
ligament
injury),
surgery
is
required to restore spinal stability. Widely
displaced fractures or comminuted C1 lat-
eral mass fractures (type IItransverse liga-
ment injuries) are initially treated with a halo
brace, and the majority heal satisfactorily
with an orthosis. Surgery is reserved for
patients
in this
category
who
develop
nonunion or persistent instability. Nondis-
placed or minimally displaced fractures are
treated with nonhalo orthoses. (From Son-
ntag VKH, Dickman CA.Treatment of Upper
Cervical Spine Injuries. In ReaG(ed.). Spinal
trauma: current evaluation and manage-
ment. Park Ridge, IL:AANS, 1993; 25-74.
With permission of the American Associa-
tion of NeurologicalSurgeons.)
Disrupted transverse ligament
FraClUres
displaced
lessthan7 mm
Displaced lateral mass or
burst fractures (>7mm),
comminuted fracture of
the transverse ligament
Insertion
r
Unilateral
ringfracture
oranterior
archfracture
80MIbraceor
Philadelphia
Halobrace
C1-C2 fusion
..
ofligamentous injury (Figs.4-15 and 4-16). Type IIodon-
toidfracturesdisplaced less than 6 mm usually heal ade-
quatelywhentreatedwith a halo brace. They have an 87 to
93%chanceofunionwhen treated with a rigid or semirigid
orthosis.38
TypeIIodontoid fractures with 6 mm or more of
densdisplacementor with comminuted fragments of the
baseofthedens(type IIAfractures) are prone to nonunion
and should be treated
with
internal
fixation.37.38 These
widely displaced
type
II fractures
have
a 75
to
85%
nonunionrate even when treated with a rigid orthosis. We
advocateearlysurgeryfor widely displaced type IIfractures
becauseof their excessively
high nonunion
rate. Type II
fracturescanoccur in conjunction with a disrupted trans-
verseIigament.39When this situation
occurs,
treatment
shouldconsist of immediate surgery for (1-(2
fusion
Multiplering
fracturesor
posteriorarch
fracture
Occipitocervical
fusion
(Fig.4-17). However, an odontoid screw cannot be used if
the transverse ligament is incompetent; a posterior fixation
must be performed.
Type III odontoid fractures usually heal when treated
with only an orthosis (Table 4-3). If nonunion occurs after
12 weeks of halo immobilization, surgery may be necessary.
These injuries have only a 2% incidence of nonunion.
Therefore, early surgery is usually unnecessary for type III
fractures.
Hangman's
Fractures
Hangman's
fractures
are vertical or oblique fractures
through
the pars interarticularis
of (2.3S.36.38.40These

42
Occipitocervical Junction: Pathology of the Occipitocervical Junction
Odontoid
Type I
Miscellaneous C2 Fracture
Figure 4-14
Classification of fractures of the second cervical vertebrae. Type I,II,and IIIodontoid fractures are, respectively, through the apex of
the dens, across the base of the dens, and into the body of C2. Hangman's fractures involve spondylitic fractures bilaterally across the pars interartic-
ularis. Miscellaneous C2 fractures include the laminae, facets, spinous process, or body of C2 (Le., nonodontoid,
non hangman's
fractures).
(With
permission from Barrow Neurological Institute.)
Odontoid
Type II
Odontoid
Type III
Odontoid Fractures
TypeI
TypeII
TypeIII
SOMlor
Halobrace
Halo brace
ORIF
Figure 4-15
Treatment
algorithm
for odontoid
fractures. Most odontoid fractures heal satisfacto-
rily with an orthosis,
except for widely displaced
type IIodontoid fractures (> 6 mm), which have a
90% chance of nonunion
when treated
with an
orthosis. Rarely, odontoid fractures can be associ-
ated with a disrupted
transverse
ligament;
this
also requires surgery for internal fixation. (From
Sonntag
VKH, Dickman CA. Treatment
of Upper
Cervical
Spine
Injuries.
In Rea G(ed.).
Spinal
trauma: current evaluation and management.
Park
Ridge, IL:AANS, 1993; 25-74.
With permission of
the
American
Association
of
Neurological
Halobrace
Surgeons.)
Less than
6 mmdens
displacement
6mm dens
displacementor
greater, or
comminuted
fracture
(lIa)

Figure4-16
lateral cervical radiograph of a type II odontoid frac-
turethatisdisplaced11mm posteriorly.This patient wastreated with
ananteriorodontoidscrew.
injuries disconnect the posterior arch of (2 from the (2
vertebralbody.They create a spondylolysis, widen the
spinalcanal,and are rarely associated with neurological
injury.Theseinjuries are most frequently caused by neck
hyperextension.When a concurrent
(1 fracture
occurs, it
usuallyinvolves the posterior
ring of (1 bilaterally
due to
hyperextension.34
Unstable Odontoid IIFractures
I
-Irreducible or recurrent subluxations
-Fracture Inonunion
-6 mm or greater dens dislocation
MRI
Intacttransverseligament
Anteriorodontoidscrewfixation
4
Trauma of the Occipitocervical Junction
43
The anterior longitudinal ligament and the (2-(3
disk
anulus and disk space can be disrupted with hangman's
injuries. This disruption can create an unstable subtype of
hangman's
injury. Injuries associated
with more than
4 mm of anterior (2-(3
subluxation or more than 11 de-
gree angulation of (2 may not heal with an orthosis.3s.4o
The angulation and displacement
are manifestations
of
extensive injuries to the soft tissues of the vertebral col-
umn. However, the majority of hangman's fractures heal
with just an orthosis (Table 4-3). APhiladelphia collar or
SOMIbrace is recommended for nondisplaced fractures. A
halo brace is reserved for displaced hangman's fractures.
Surgery is indicated
for injuries
that cannot be kept
aligned satisfactorily in a halo brace, for patients who de-
velop a nonunion, or for hangman's
injuries associated
with locked (2-(3
facets (Figs.4-18 and 4-19).
Miscellaneous (2 Fractures
Miscellaneous
(2
fractures
refer
to any (2
fracture
that does not involve the odontoid process or the pars
interarticularis
of (2 (Le., nonodontoid,
nonhangman's
fracture). These include fractures
of the (2 body, C2
laminae, (2 spinous process, or (2 facets. Most of these in-
juries
heal satisfactorily with an orthosis (Table 4-3).
Nondisplaced, minor fractures are treated with a Philadel-
phia collar or SOMIbrace. Displaced or extensive fractures
are treated with a halo brace. Surgery is reserved for cases
that
fail treatment
with an orthosis
or that
develop
nonunion.
Disrupted transverse ligament
Figure 4-17
Algorithm for treatment of un-
stable type II odontoid fractures. Widely dis-
placed fractures (more than 6 mm) or patients
who have failed treatment with an orthosis or
who havedeveloped nonunions arecandidates
for surgery. Odontoid screw fixation can only
be used when the transverseatlantalligament
is intact. If the ligament is incompetent, an
odontoid screwwill not restore atlantoaxial in-
stability even though the fracture is fixated.
(From Sonntag VKH, Dickman CA. Treatment
of Upper Cervical SpineInjuries. In ReaG(ed.).
Spinaltrauma: current evaluation and manage-
ment. ParkRidge,Il: AANS,1993; 25-74. With
permissionof the AmericanAssociationof Neu-
rological Surgeons.)
I
C 1-C2 fusion
I
-C1-C2
screw
fixation
-C1.C2
wire/graft
-Halifaxclamps

44
OccipitocervicalJunction: Pathology of the Occipitocervical Junction
Hangman's Fracture
TypeI
-NondispJaced
-Minimally
displaced
Type II
-Angulated> 110
-Subluxation> 4mm
~
TypeIII
-Locked
C2-C3
facets
Irreducible
or
recurrent
subluxation
Reducible
Figure 4-18
Most hangman's
fractures are
treated
satisfactorily with a sternal-occipital-
mandibular-immobilization (SOMI)or halo brace.
Surgeryisreservedfor patients with severe associ.
ated ligamentous injury, when orthoses fail to
maintain alignment, or when associated with
locked C2-(3 facets. (From Sonntag VKH,Dick.
man CA.Treatment of Upper Cervical Spine In-
juries.ln ReaG(ed.). Spinaltrauma: current evalua.
tion and management. ParkRidge,IL:AANS,1993:
ORIF
25-74. With permission ofthe AmericanAssocia.
tion of NeurologicalSurgeons.)
SOMIor
Halobrace
ORIF
Halobrace
Figure 4-19
Lateralradiographofa hangman's fracture associated withbi.
laterallylockedC2-(3 facets. The hangman's fracture creates a spondyloly-
sis,separating the C2bodyfromthe posteriorarch.Thisfracture was reduced
surgicallybecause traction would have risked distracting the cervicalseg-
ments.
Combination
Atlas-Axis Fractures
logical injury and a higher rate of nonoperative treatment
failure compared
with isolated atlas or axis fractures
(Tables 4-1 and 4-3). These injuries should be evaluated
with a combination of plain radiographs. CT,and MRIto
determine
the
extent
of bone
and
ligament
injury.
When the transverse atlantal ligament is disrupted. early
surgery is advocated because the transverse ligament will
not heal.
Similar to the treatment
of isolated C1 or C2 fractures.
atlantoaxial fractures are treated according to the extent
of bony and ligamentous injuries (Fig. 4-20, Table 4-3).
Combination fractures are relatively common; they account
for 44% of alI C1 fractures and 16%of alI C2 fractures.34
Combination C1-C2 fractures have a higher rate of neuro-

-
Ire
~I-
~e.
Ici-
to
,th
~k-
Iln-
ua-
S3;
tia-
r
bi-
loly-
ced
Iseg-
tlent
~ures
~ated
~I to
r
ury.
arly
will
iI
4
Traumaof the OccipitocervicalJunction
45
C, - Odontoid Type II
C, - Miscellaneous
Fractures
CI -Odontoid Type III
CI - Hangman's
Fracture
Figure4-20
Combination fractures involving both the atlas and axis are treated
based on the extent of instability
of the C1 fracture
(Le., whether
thetransverseligament is incompetent)
and the extent of the C2 fracture.
Combination
atlantoaxial
injuries associated with type II odontoid
frac-
turesarethe most common subtype of injury and also require surgery
more often than isolated
type II fractures.
(From Dickman
CA, Hadley MN,
BrownerC,et al. Neurosurgical management
of acute atlas-axis
combination
fractures:
a review of 25 cases. JNeurosurg
1989;70:45-49.
Used with
permission.)
Theextentof boneinjury isthe other major determinant
ofthemethodof treatment of C1-C2 fractures. Among
combination(1-(2 injuries associated with odontoid type
"fractures,healingis primarily influenced by the amount
ofdensdisplacement(Fig.4-21). Ifthe dens is displaced 6
mmormore,internal fixation is recommended because of
thehighrateof nonunion associated with widely displaced
type IIfractures. If the dens is displaced less than 6 mm, a
halo brace is adequate. Combination C1-C2 fracture in-
juries, associated with odontoid type III,hangman's, or mis-
cellaneous C2 fractures, can often be treated successfully
with a halo brace. However, combination (I-C2 fractures
are more likely to require surgery for internal fixation com-
pared with isolated C1or C2fractures (Table4-3).

46
Occipitocervical Junction: Pathology of the Occipitocervical Junction
F
Figure 4-21
This 10 mm posteriorly displaced type IIodontoid frac-
ture was associated
with fractures
of the lateral mass of C1. The pa-
tient was treated with posterior C1-C2 fusion because of the high risk
of nonunion associated with his widely displaced odontoid fracture.
.
Injurieslikely to FailNonoperative
Treatment
Several types of injuries of the occipitocervical junction
are highly unstable and should be considered for surgical
intervention.
Such injuries include those that are not
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immobilized satisfactorily with a halo brace; have
recurrent subluxation, reangulation, or malalignment; or
result in nonunion after an adequate
trial of external
immobilization.
Extensive crush injuries to the bones
or fractures associated with disruption of the major liga-
mentous stabilizing structures
fall into this category of
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the transverse atlantalligament,24.25 axis fractures associ-
ated with transverse atlantalligament
disruption,39 typeII
odontoid fractures with 6 mm or greater dispiacement,J8
extensively
comminuted
C2 fractures,38 or hangman's
fractures with C2-C3 subluxation of more than 4 mm and
greater than 11degree C2body angulation35.4oexemplify
this type of unstable injury. These mixed ligamentous and
bony injuries are characterized
by wide bone displace-
ment, fracture angulation, subluxation,
and extensively
comminuted
fractures.
They are highly unstable
and
typically have a high rate of nonunion when treated non-
operatively. Alignment of the spine usually cannot be sat-
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They also tend to develop nonunion
or a malaligned
union.
. Summary
Traumatic injuries of the occipitocervical
junction
are
treated based upon the extent of the injuries to the bone
and ligaments that are responsible for maintaining spinal
stability. Isolated ligamentous injuries tend to be highly
unstable and do not heal with nonoperative management
because
disrupted
ligaments
are incapable
of repair.
Minimally displaced or nondisplaced bony injuries tend to
heal satisfactorily with an orthosis. Combined injuries of
the bone and ligaments and extensively comminuted,
widely displaced fractures tend to require surgery for inter-
nal fixation to restore stability
to the occipitocervical
junction. It must be emphasized that, although general
guidelines can be formulated, treatment options should be
individualized.
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Pang D. Wilberger
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WE. Basilar
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develop-
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and
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Yale J Bioi Med
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Dublin AB. Marks WM. Weinstock
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of
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survival:
-
~~
~
.,,"'~=~~~~;~-;;'""'~~

with a radiographic
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AJNR Am J Neuroradiol
1987;8:995-999
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fractures
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overlooked
en-
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occipital dislocation.
Neurosurgery
1979;4:
12-17
18. Traynelis
VC. Marano
GO.
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19. Wackenheim
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Diagnosis
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Or-
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21. Fruin AH. Pirotte
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case
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Neurosurg
1973;39:394-397
23. Watridge CB. Orrison
WW. Arnold
H. et al. lateral
atlantooccipital
dis-
location: case report.
Neurosurgery
1985;17:345-347
24. Spence KFJr. Decker
MS. Sell KW. Bursting
atlantal
fracture
associated
with rupture
of the transverse
ligament.
J Bone Joint
Surg
Am
1970;52:543-549
25. DickmanCA.Greene KA.Sonntag
VKH. Injuries
involving
the trans-
verseatlantalligament:
classification
and treatment
guidelines
based
uponexperience with 39 injuries. Neurosurgery
1996;38:44-50
26. DickmanCA.Mamourian
A. Sonntag
VKH. et al. Magnetic
resonance
imagingofthe transverse
atlantalligament
for the evaluation
of at-
lantoaxialinstability.J Neurosurg
1991 ;75:221-227
27. CooperPRoMaravilla KR.Sklar FH. et al. Halo immobilization
of cervical
spinefractures: indications and results.J
Neurosurg
1979;50:603-610
4
Trauma of the Occipitocervical Junction
47
28. Johnson RM. Hart DL. Simmons EF.et al. Cervical orthoses: a study
comparing
their effectiveness
in restricting
cervical
motion
in normal
subjects.J
BoneJoint
Surg Am 1977:59:332-339
29.
Koch RA. Nickel VL The halo vest: an evaluation
of motion
and forces
across the neck. Spine 1978;3:103-
107
30.
Marciano FF. Greene
KA. Mattingly
LG. et al. Halo brace immobiliza-
tion of the cervical spine: a review of principles
and application
tech-
niques. BNI Q 1994;10:13-17[p4]
31.
Hadley
MN. Dickman
CA. Browner
CM. et al. Acute traumatic
atlas
fractures:
management
and
long
term
outcome.
Neurosurgery
1988;23:31-35
32. Jefferson G. Fracture of the atlas vertebra: report of four cases. and a
review ofthose
previously
recorded.
BrJ Surg 1920;7:407-422IpS)
33. Jonsson HJr. Bring G. Rauschning W.et al. Hidden cervical spine in-
juries
in traffic accident
victims
with skull fractures.
J Spinal Disord
1991 ;4:251-263
34.
Dickman CA. Hadley MN. Browner C. et al. Neurosurgical manage-
ment of acute atlas-axis
combination
fractures:
a review of 25 cases.
J Neurosurg
1989;70:45-49
35.
Effendi B. Roy D. Cornish
B. et al. Fractures
of the ring of the axis: a
classification
based
on the analysis
of 131 cases. J Bone Joint Surg Br
1981 ;63-B:319-327
36.
Good J. Judicial hanging.
lancet
1913:193-194
37.
Hadley MN. Browner CM. Liu 55. et al. New subtype
of acute odontoid
fractures (type IIA). Neurosurgery 1988;22(1 Pt 1):67-71
38.
Hadley MN.Dickman CA.Browner CM.et al. Acute axis fractures: a
review of 229 cases.J
Neurosurg
1989;71(5
Pt 1):642-647
39.
Greene KA. Dickman CA. Marciano FF.et al. Transverse atlantal
ligament
disruption
associated
with
odontoid
fractures.
Spine
1994;19:2307-2314
40.
Bucholz
RW. Unstable
hangman's
fractures.
Clin Orthop
1981; 154:
119-124

5
Transoral Approaches to the Craniocervical
Junction: General Principles
David Choi and H. Alan Crockard
.
Classification
ClassicTransoral Approach
Extended Transoral Approaches
. Anatomy
.
Indications
.
Contraindications
.
Advantages
.
Disadvantages
.
Objectives
.
Pathology of the Craniocervical Junction
Rheumatoid Arthritis
Odontoid Fractures and Os Odontoideum
Nonrheumatoid
Cranial Settling and Atlantoaxial
Instability
Congenital Malformations
BoneSoftening Diseasesand Disorders of Metabolism
In1909,Kanavalfirstdescribeda transoralapproachto the
craniocervicaljunction (CCj)when he removed a bullet that
was lodged between the lower margin of the foramen
magnum and the arch of Cl. The approach was later
advocated by Scoville and Sherman and used extensively
by Fangand Ong for the treatment of infections in this area.
Further refinements have been described by Greenberg et al
in 1968, Grison in 1967,Fokeset al in 1977,Menezes et al in
1980,and, more recently, Crockard in 198sya-r
The unique an'!tomy and biomechanics of the occipitoat-
lantoaxial complex make any approach to this area a
formidable challenge. For successful surgery, a thorough
knowledge of the variations in embryonic development of
the CCjis required, together with an understanding of the
wide spectrum of pathologies that may be encountered.
Before embarking on surgery individual patients must be
carefully assessed; for example, to ensure that disease of
the temporomandibular joints does not restrict opening of
the mouth, or a fixed flexion deformity of the neck does not
preclude satisfactory access.
48
Tumors
Infections
.
Clinical Presentation
Clival lesions
Foramen Magnum lesions
.
Radiological
Evaluation
.
Preoperative Evaluation
Anesthesia 19
.
Surgical Techniques
.
Outcome
.
Complications
Intraoperative
Postoperative
.
Conclusion
Surgical access to the midline skull base, foramen mag-
num, and upper cervical spine can be achieved by a variety
of approaches but in our opinion the transoral routes pro-
vide
the
most
direct
access
to
midline
extradural
pathology.2
.
Classification
The approaches
may be classified as classic or extended.
ClassicTransoral Approach
. With palatal sparing
.
With splitting of the soft and hard palate
In general terms a classic transoral
procedure
(with
sparing of the palate) will expose the anterior rim of the
foramen magnum, allowing access to the arch of C1and

5
TransoralApproachesto the CraniocervicalJunction:GeneralPrinciples
49
theodontoidprocess.Splitting the soft and the hard palate
'thetranspalatalapproach) will expose the lower third of
theclivusbutwith limited lateral access2(Fig.5-1).
Extended
Transoral Approaches
. Upper extension by "open-door" maxillotomy or the
transmaxillary"degloving" approach with hard palate
intact
. Lowerextension by the median trans mandibular
and/or
transglottic approach
Theextended maxillotomy ("open-door" variant) pro-
videsaccess to the whole of the sphenoid and clivus from
Figure 5-1
The classic transoral route
withthe appropriate instrumentation.
the ethmoids to the lower border of C2vertebra.Thisap-
proach was developed in response to the challenges of pro-
found basilar invagination seen in osteogenesis imperfecta
and for extensive midline tumors such as chordomas and
chondrosarcomas3 (Fig.5-2).
The
transmandibular
(median
labiomandibulotomy
and/or glossotomy) approach is a caudal extension of the
classic transoral procedure and affords excellent visualiza-
tion of the anterior
CCJ down to the C3- C4 vertebral bodies.
It is used as part of a 360 degree excisionof vertebral tu-
mors in the upper cervical spine and craniovertebral junc-
tion4(Fig.5-3).

50
OccipitocervicalJunction:AnteriorApproach
Figure 5-2
The target point of the "open-door" maxillotomy in basilar invagination.
Figure5-3
The target point of the transman.
dibularapproach to lesionsofthe (2-(3 area.

5
TransoralApproachesto the CraniocervicalJunction:GeneralPrinciples
51
. Anatomy
Embryologically,the clivus consists of two bones; the
basisphenoid and the
basiocciput,
extending
from
the
foramenmagnum to the sphenoid
sinus.
The clivus
is
wedge-shaped(38-42 mm long) being -25 mm thick at its
rostralend and 3 mm at the foramen magnum. It is 22 to 26
mmwide in the adult and this represents
the "safe" area
betweenthe carotid arteries rostrally and the lower cranial
nervesandvertebral arteries caudally (Fig. 5-4). The CCJ
consistsof the oval-shaped foramen magnum, the atlas, and
the axis. These structures
along
with
their
associated
ligamentsprotect the brain stem and upper cervical spinal
cordwhileallowing movement (Fig. 5-5). The foramen
magnumis formed by the basilar and lateral parts of the
occipitalbone. The basilar part is formed
by fusion of the
occipitalbone and the clivus. The use of computed
tomog-
raphy(a) with multiplanar reconstructions and magnetic
resonanceimaging (MRI) has increased
our understanding
and definition of abnormal
anatomical
relationships
at
theCCj.5
ICarotid art. 11
r<
~
I
I
I
1
The key to surgical exposure for this whole area is the
identificationof the embryologicalmidline: the septal attach-
ment to the sphenoid rostrally and the anterior tubercle on
the arch of C1at the CCJ.The vertebral arteries run 14 to 15
mm on each side lateral to the tubercle (medial aspect of
the foramen transversarium of the atlas). The distance be-
tween the points of dural entry of the vertebral arteries
measures 20 to 22 mm (Fig.5-4).
The apex of the petrous bone is contained within the pha-
ryngeal attachment and meets the clivus (petro-occipital
fissure) at the foramen lacerum. At this point the internal
carotid artery may be damaged because it is not protected
by bone. Intradurally from this point, the abducens nerves,
the inferior petrosal sinuses, and the hypoglossal nerves are
at risk, being 10 to 11 mm, 15 mm, and 13 mm from the
midline, respectively.6
Anatomical landmarks of the midline skull base and upper
cervical vertebrae, as seen by the transoral surgeon, include
the anterior atlantal tubercle and the pharyngeal tubercle.
Attached to the former is the anterior longitudinal ligament,
and to the latter the superior constrictor of the pharynx.
Figure 5-4
The ventral surface of the
pontomedullary junction after divectomy
with "open-door" maxillotomy. The safe
boundaries of divectomy
between the
carotid arteries rostrally andthe vertebral
arteries caudally are shown. Inset: intra-
operative photograph showing the dival
defect and panoramic view of the verte-
brobasilarjunction.

52
OccipitocervicalJunction:AnteriorApproach
Apical Ligament
Alarlig.
.
Indications
. Todecompress the cervicomedullary junction when ir-
reducible ventral bony pathology causes compression of
the neuraxis
.
When a soft tissue mass, such as rheumatoid pannus or
pseudotumor,
causes compression
7
.
Extradural tumors with limited lateral extension
.
Rarely,for pure intradural tumors that are not accessible
by the far lateral approach8
.
Extremely rarely, and perhaps historically,for a midbasi-
lar aneurysm9
.
Contraindications
. Oral sepsis
.
Asuperior-inferior gap of less than 25 mm between the
upper and lower teeth will not allow a conventional
transoral approach. In these cases an extended "open-
door" m,,\xillotomy for rostral exposure or midline
mandibulotomy and/or glossotomy for caudal exposure
may be used.7
. Fixed flexion deformity of the head on the neck at the
CCJ.This does not allow sufficient opening of the mouth,
and use of surgical instruments
is hindered by the
manubrium.
.
Tumors extending laterally more than 15 mm from the
midline may require additional surgery by a lateral or
posterolateral approach.
.
Advantages
The anatomy of this approach is consistent and familiar to
the suitably trained surgeon; direct exposure of the clivus is
possible, unhindered by cranial nerves or major blood ves-
sels. Thisis particularly true for:
Figure 5-5
The (1-(2
complex with associ-
ated ligaments(transoralview).
.
Primary ventral midline lesions, especially in the middle
or upper third of the clivus
.
Lesions confined to the defined safe anatomical bound-
aries of the clivus
.
Extradural lesions arising from the clivus with sec-
ondary midline intradural invasion
.
Disadvantages
There are several disadvantages to the transoral approach:
.
Adeep and narrow working space
. Superiorly limited by the pterygoid plates anteriorly and
the carotid arteries posteriorly, and laterally by the hy-
poglossal canals, the eustachian tubes, and the vertebral
arteries at C1-C2
.
More inferior access requires a transglottic approach.
.
It can be difficult to close the dura, thus increasing the
risk of cerebrospinal fluid (CSF)leakage and infection.
.
Lateral extension of purely intradural lesions may best
be approached by a subtemporal, suboccipital, and/or
transpetrous route.
.
Tumors involving the occiput, the occipital condyle, the
upper cervical spine, or encasing the vertebral or basilar
arteries
can be difficult to remove by the transoral
approach.5.6
.
Objectives
. To remove ventral compression of the brain stem and
cord
.
Toexcise or debulk tumor
.
To obtain a diagnosis in the case of tumor or infections
.
To stabilize the CCJ.This is not easily achieved transorally
and
is usually
performed
by second
stage
posterior

5
TransoralApproachesto the CraniocervicalJunction:GeneralPrinciples
53
instrumentation. Anterior metal work and bone graft are
moreprone to failure and non fusion.
. Pathologyof the Craniocervical
Junction
RheumatoidArthritis
Rheumatoidarthritis
is an erosive
synovitis
causing
pol-
yarthropathyassociated with multiple
micro-tears
in liga-
ments,disruption of collagen, repair, and infiltration with
fibroustissue. The involvement
of the transverse ligament
and the alar-apical
complex, as well as the capsular
liga-
ments of the lateral mass joints, dramatically
alters the bio-
mechanicalfunction
of the
CC]. Erosion
of
the
lateral
masses of either
or both the atlas
and
the axis allows
translocationof the odontoid
peg. Skull traction
by itself,
therefore,will
not be able to restore
and maintain
the
normalanatomical configuration
after odontoid
transloca-
tionhasoccurred. The lateral
radiograph
may look correct
but the absence of lateral
masses
cannot
maintain
the
reducedposition.
Whether
the odontoid
peg ascends
through the
foramen
magnum
(vertical
translocation)
depends on:
. The degree of erosion in the
lateral
mass joints
and
whether this is symmetrical
. Thedegreeof erosion and inflammatory
change around
thetip of the odontoid peg
.
Possible pathological fractures of the odontoid
peg
Amobiletranslocated odontoid may become impacted,
givingafalsesenseof stability because of lack of movement
onflexion-extensionlateral radiographs. Whether fixed
or mobile,mechanical trauma
of the neuraxis occurs,
whichisin effectpulled over a fixed bony point with every
movementof the head.Generally, anterior decompression
isrecommendedfor those patients with neuraxial com-
pressionand a significant anterior pannus and/or irre-
ducibleodontoid process, or marked (> 5 mm) vertical
translocation.10
Odontoid
FracturesandOsOdontoideum
Instabilityof nonunited or malunited dens fractures may
beassociated with progressive
myelopathy.
The trans-
verseligament or other soft tissues may become inter-
posedat the fracturesite, resulting in nonunion. Forthis
reason,odontoid
screw fixation will be unsuccessful,
withahigh rate of pseudarthrosis.11 Modern MRIallows
visualizationof the ligaments at the CCJ.Careful atten-
tionto theposition of the transverse ligament will allow
optimalplanning of the surgical approach. The cervical
spinalcordandthe inferior part of the medulla oblongata
maybe compromised
depending
on the
degree
of
translocationof the dens, lateral translation
of the atlas,
pseudohypertrophyof the soft tissues, and movement of
thedens.
Generally,odontoidectomy is appropriate in:
.
TypeIIodontoid fracturesolder than 6 to 8 weeks that
are not immobilized
satisfactorily
and have excessive
angulation
and malalignment
causing
compression
of
the cervicomedullary junction
. MalunitedtypeIIodontoidfractureswith intervening
soft tissue or extensively comminuted fractures, after an
adequatetrialof externalimmobilizationor internalfix-
ation or both
An os odontoideum, in our opinion, is not a developmen-
tal defect but rather a "fracture" through the cartilaginous
odontoid in utero, at childbirth, or in early childhood.12In-
terpositionof the transverseligamentis usuallyseen,with
localdeformity caused by ventral translation of the atlas.
Down syndrome is a "congenital" example of this trauma.
The os itself rarely causes neuraxial compression, and the
aim of surgery is usually to stabilize the CCJfrom behind.
Surgery is also indicated for fixed ventral compression of
the neuraxis due to subluxation or pseudotumor.
Nonrheumatoid CranialSettling
andAtlantoaxial Instability
. Ankylosingspondylitis
. Psoriasis
..
Scleroderma
Other spondylarthropathies and enthesopathies
Erosive arthritic disease associated with inflammatory
bowel disease is uncommon but can result in ligamentous
laxity and joint instability. Significant occipitoatlantal insta-
bility is a recognizedfeature of theseconditionsand may
cause high cervicomedullary tetraplegia, requiring a com-
bined anterior transoral decompression and posterior oc-
cipitocervical fusion.
CongenitalMalformations
. Primary basilar invagination and platybasia13 (Fig. 5-6)
. Congenitalanomaliesof the odontoid
process (ossicu-
lumterminale)
.
Assimilation or occipitalization of the atlas
and segmen-
tation defects (Klippel-Feil deformity) with secondary
basilar invagination
. Chiarimalformations,especiallyif associatedwith a
bony deformity
Anterior
decompression
is recommended
for those
patients with neuroaxial compression and significant ante-
rior pannus, and/or irreducible odontoid process, or marked
(> 5 mm) vertical translocation.
PIcheckword
"neurax"
BoneSofteningDiseasesand Disorders
of Metabolism
Basilar impression and platybasia occur in these conditions
due to a loss of structural integrity at the skull base. Softening

54
OccipitocervicalJunction:Anterior Approach
Figure 5-6
Magnetic resonance image obtained in a patient with
symptomaticcervicomedullaryneuraxialcompressiondue to primary
basilarinvagination.
of the skull base may have profound effects on the neural
structures that it normally supports and protects.14
.
Osteogenesisimperfectaand Hajdu-Cheneysyndrome
(acro-osteolysis).
.
Paget's disease
.
Mucopolysaccharidoses (e.g., Morquio-Brailsford's dis-
ease, Hurler's and Hunter's syndromes).
Tumors
Many different neoplasms may occur in this area, arising
from embryological rests or dysplastic tissues of the skull
base. The neurovascular
structures
of the CC] can be
displaced in various directions by tumors: masses in the an-
terior midline displace structures
dorsally and laterally
(Fig. 5 -7). This distorted anatomy allows a safer transoral
approach for diagnostic biopsy or definitive surgery, but
when there is lateral extension, the far lateral (dorsolateral)
suboccipital approach to the lower clivus and anterior por-
tion of the foramen magnum is preferred.
The main tumors that involvethe CC]are primary and sec-
ondary neoplasms and tumors with transdural extension.
Primary Neoplasms
. Chordoma, chondroma, chondrosarcoma, plasmatocy-
toma, eosinophilic granuloma, and fibrous dysplasia IS
Figure 5-7
Magnetic resonance image obtained in a patient with
chordoma
of the dival region. Note the extensive invasion of the tu.
mor into the predival area and the intradural extension anteriorly to
the pontomedullary junction.
Secondary Neoplasms
.
Metastases, nasopharyngeal malignancy, craniopharyn-
gioma, and ectopic pituitary tumors
Tumors with Transdural Extension
. Meningioma and neurofibroma, glomus tumors, rhab-
domyosarcoma, neurenteric cyst, and pheochromocy-
toma. These should rarely be approached transorally.
Infections
. Tuberculosis is an infrequent but recognized cause of
cervicomedullarycompression.
.
Staphylococcalabscesses in neonates or immunosup-
pressedadults
.
Brucellaand,rarely,fungalinfections
Draining these aggressive lesions by the transoral ap-
proach, together with appropriate antimicrobial therapy, is
the treatment of choice.
.
ClinicalPresentation
Symptoms and neurological signs may be attributed to:
.
Instability of the craniocervical junction
(neck pain,
headaches and occipital neuralgia, C2root pain, clucking
sign, and torticollis)
.
Myelopathy (paresthesia, numbness, weakness, sphincter
disturbance,
L'hermitte's
phenomenon,
hypereflexia,
clonus, extensor plantar response)

5
Transoral Approaches to the CraniocervicalJunction: General Principles
55
. Vertebrobasilarischemia (dizziness, vertigo, syncope,
nystagmus,and brain stem vascular syndromes).
In the
past this has been attributed
to pathology
at the CCJ
causingvascular compromise,
but more
recently
MRI
andmagnetic resonance angiography (MRA) suggest that
thisisnotas commonas was once thought.
. Pontomedullarycompression (dysarthria,
dysphonia,
dys-
phagia,diplopia, facial numbness, sleep apnea, and
nightmares),as well as cranial nerve palsies with long
tractsignsand respiratory difficulties depending on the
degreeofcompression.2.16
. Headandneckpain It is not uncommon for neoplasms
involvingthe cranial base and upper cervical spine to
presentwith only vague symptoms of headache and
neckpain.When the reserve of the cisterns at the CCJis
exhausted,symptoms and signs rapidly progress. One of
the most common complaints
is pain in the C2 der-
matomethat is aggravated
by changes
in neck position
andbyassuming the upright position. This may be a sign
that the occipital condyles are affected, implying lateral
extensionof the tumor and contraindicating
a transoral
approach.
. Wastingoftheintrinsic musclesof the handsAfalse local-
izingsign,which is fairly common but may go unnoticed,
firstdescribedby Symmonds17
Clivallesions
. Uppercranial nerve palsies
by compression
of brain
stemnuclei,compression of the subarachnoid
portion of
nerves,or traction of nerves (dizziness,
vertigo, hearing
loss,and downbeat nystagmus)
. Pyramidalsigns
. Symptomsand signs of hydrocephalus,
syringohy-
dromyelia,and/or syringobulbia due to alteration
of
(SFdynamicsat the aqueduct of Sylvius and IVven-
tricle
. Paresthesiasor dysesthesias of the hands, limbs, or face
ForamenMagnum Lesions
. Involvementof the lower cranial nerves (IX,X,XI,
XII)
. Vertebrobasilar symptoms
such as migraine
and tran-
sientvisual loss, drop attacks, and paresthesias
. Spasticweakness of the extremities
with progression
of
motor symptoms, which
may begin
in the ipsilateral
upper limb, followed by weakness
of the contralateral
lowerlimband progressing to the contralateral upper
limb due to compression of the pyramidal decussations.
"Cruciate paralysis" and dissociated sensory loss are of-
ten associated with pressure on the upper portion of
the pyramidal tracts and an intramedullary
process,
respectively.
.
Isolated weakness of the intrinsic muscles of the hands 17
. Sensory abnormalities resulting from pressure on the
medial lemniscus
.
Very occasionally, patients may have complaints due to
cerebellar dysfunction.
.
Radiological Evaluation
1. Plainx-rays including dynamic flexion-extension im-
ages and open-mouth views. McGregor's line is drawn
from the hard palate to the lowermost part of the oc-
ciput and Chamberlain's line from the hard palate to
the anterior tip of the occiput (opisthion). These lines
were important in the prescanning era but their signifi-
cance is now historical since neuronavigation has been
developed.
2.
a-scans, axial and coronal reformatted images using
soft-tissue and bone algorithms are useful, together
with three-dimensional
(3D) reconstruction
of the
images. CT scanning
may be supplemented
with
subarachnoid injection of contrast media (computer-
ized myelotomography) to demonstrate the important
contribution of proliferative rheumatoid pannus be-
hind the odontoid peg in ventral cervicomedullary
compression.
3. MRIscanshelpto definethe relationshipofthe pathol-
ogy to the brain stem, cervical spinal cord, and vertebral
arteries. Gradient-echo sequences and contrast images
assess soft tissue pathology and the integrity of the lig-
aments of the C1- C2 complex, an important factor in
surgical planning (Figs.5-6 and 5-7).
4.
MR angiographyor digital subtractiveangiographyis
necessary in tumor surgery with possible embolization
and is helpful in some cases of congenital or acquired
anomaly. Sometimes the vertebrobasilar
system can
be seen to occlude with changes in head position.
In complex malformations preoperative angiography
may identify obstruction or kinking of the vertebral
artery depending on the patient's clinical symptoms
and signs.
5.
Neuronavigation systems have allowed conventional
data to be used in the operating theater to greater
advantage (Fig. 5-8). At present, however, most sys-
tems cannot be used accurately below the foramen
magnum.

56
Occipitocervical
Junction:
Anterior
Approach
l
Figure 5-8
The neuronavigational
system used during the transoral approach. helping to plan accurate surgical corridors and confirm that opera-
tive objectives are accomplished. and the second stage of occipitocervical fixation.
.
Preoperative Evaluation
.
Bacteriologicalswabs of the nasal and oropharyngeal cav-
ity should be taken. Ifan unusual organism is identified
and postoperative infection ensues. the patient is given
the appropriate antibiotics. Usually antibiotics (cefurox-
ime and metronidazole) are administered with induction
of anesthesia and continued during the first 2 postopera-
tive days. Long-term antibiotics should be avoided.
. Somatosensoryevoked potentials(SSEPs)are used
preoperatively as well as intraoperatively for neurophys-
iological monitoring. recording electrical signals at dif-
ferent levels of the neuraxis and relevant muscle groups
(Fig.5-9). Such real-time information helps to alert the
surgeon that certain maneuvers might produce irre-
versible damage and morbidity.
.
Motor evoked potentials
(MEPs) are used but the
value is limited due to the proximity of the cerebral
peduncles. IS
Anesthesia
19
.
Fiberoptic nasotracheal intubation is performed in the
awake patient. Preoperative tracheostomy
is reserved
for patients with lower cranial nerve deficits and those
with neurological compromise necessitating prolonged
ventilation before and possibly after the operation. and
in extended transoral procedures (maxillotomy and me-
dian labiomandibulotomy with or without glossotomy).
The main reason for intubation in these patients is to al-
low optimal surgical access. especially in the presence
of craniofacial abnormalities.
. A nasogastric (ng) tube is inserted in classic transoral
surgery when gastric emptying and ng-feeding are re-
quired only for a short time after the operation. Apercu-
taneous endoscopic gastrostomy (PEG)is placed preoper-
atively in patients who have a bulbar palsy and in those
undergoing an extended transoral approach when pro-
longed enteral feeding is usually required. 20

5
TransoralApproachesto the CraniocervicalJunction:GeneralPrinciples
57
. Pulmonaryfunction (vital capacity, arterial blood gases,
andoxygensaturation)
are assessed
preoperatively
and
followedintraoperatively.
A vital capacity
of less than
1.2Lis associated with a greater
risk of postoperative
complications.
. Alumbardrain is inserted after the induction of anes-
thesiaandprior to surgery in cases where there is a pos-
sibilityofdural tears and CSFleakage. This is more com-
monintumor surgery and severe vertical translocation
ofthe odontoid
peg.
. SurgicalTechniques
Thepatient is placed in the three-quarter
supine
position,
tiltedtoward the surgeon, or fully supine with lateral tilt of
theoperating table. Head rotation
by itself on the fully
supinebodyis not advised because this will rotate the ver-
tebralarteries into the operative
field. This position allows
thesurgeonto be seated comfortably
and encourages
blood
andwashingsto drain away from the operative field. A
right-handedsurgeon would sit or stand
on the patient's
rightside,and a left-handed surgeon on the patient's left.
Theheadis placed in a three-pin
fixation system (such as a
Mayfieldclamp) or on a padded
horseshoe
headrest,
with
10to15degrees of neck extension,
which alIows easier ac-
cessandopening of the mouth (Fig. 5 -10).
Adedicated transoral system (Crockard transoral
instru-
ments,Codman Raynham, MA, USA)makes these procedures
easierandsafer.This includes an oral retractor/tongue
depres-
sor,attachableretractors for the soft palate and endotrachial
tube(ET)/ngtubes (in classic transoral surgery), a long
monopolardiathermy cutting blade, and appropriate
bayo-
netedinstrumentsofsufficientlength.Additionalcomponents
areavailablefor performing extended transoral surgery.
Anoperating microscope with a 300 mm objective
lens provides helpful illumination
and magnification.
Figure 5-9
Electrophysiological monitoring is ex-
tremely useful during transoral procedures, helpingto
reduce morbidity.
A high-speed air drill with different burrs is used to pro-
duce adequate bone decompression or tumor resection. The
transoral approach for tumors has evolved in the past few
decades due to the increased
anatomical
information
Figure5-10
The alignment ofthe surgeon, operative microscope,
and patient's oral cavity avoiding head rotation.

58
OccipitocervicalJunction:AnteriorApproach
provided by superior imaging, neuronavigational
tech-
niques, the development of special surgical tools (e.g.,ultra-
sonic aspirators), and more effective spinal instrumentation.
The oropharyngeal cavity is cleaned with an aqueous so-
lution of 0.5%chlorhexidine (Cetavlon).The mouth, tongue,
and lips are coated abundantly with topical 1%hydrocorti-
sone ointment to minimize postoperative swelling. Local
anesthesia (1%lidocaine with 1:200,000 adrenaline) is in-
jected submucosally at the back of the pharynx, prior to
making a vertical incision through the mucosa (for a classic
transoral). The mucosa is then retracted with a dedicated
pharyngeal retractor, exposing the deeper muscle layer.The
longitudinal muscles posterior to the mucosa (longus colli
and capitis) are elevated from the underlying foramen mag-
num, C1,and C2with diathermy, and retracted back to ex-
pose the bone, ready for decompression with the drill.Tore-
move the odontoid process, the tough apical and alar
ligaments must be divided by sharp dissection or diathermy.
It is important to avoid a dural tear to prevent CSFleakage.
In tumor surgery this is particularly important. The dura
should never be breached unless there is already intradural
spread of tumor, to minimize the chances of intradural seed-
ing and recurrence at a later date. Detailed descriptions of
odontoidectomy, tumor removal, extended procedures, and
wound closure may be found in Chapters 6, 7,and 8.
. Outcome
Since 1983,the senior author has performed more than 400
transoral operations. The mortality rate depends on many
factors, but the most important predictor of outcome is the
degree of preoperative neurological impairment. Rheuma-
toid patients who are bed-bound or unable to walk due to
brain stem and cord compression (Ranawat classification
IIIb)have a mortality rate of -12%, compared with 0%in pa-
tients who are relatively independent (Ranawat I).This also
applies to other pathological conditions.21.22
.
Complications
Complications
may occur intraoperatively
or postoperatively.
Intraoperative
Intraoperative complications can be avoided if the surgeon
anticipates and avoids certain pitfalls:
1.
Vascularinjuries (vertebral, carotid arteries, venous si-
nuses) may occur if there has been rotation of C1dur-
ing the positioning of the patient, causing disorienta-
tion of the surgeon.
2.
Cerebrospinalfluid leakage Take time and care while
dissecting tumor or bone off the dura. If a tumor
crosses the dura, a lumbar drain should be inserted pre-
operatively, and CSFdrained during the operation at a
rate of 10 to 15 mL/hour and for -5 days thereafter.
.
3.
Soft tissue swelling (tongue and lip) may occur due to
venous congestion and edema. Checkthat the tongue is
not caught between the transoral retractor and the
teeth, and liberally apply and reapply hydrocortisone
ointment during the procedure.
4.
Cranialnervepalsies
Postoperative
1.
Localinfection and wound breakdown When opening,it
is important to make a clean incision in the mucosa and
to use pharyngeal retractors with care so as not to dam-
age the edges of the mucosal incision. This will allow
good apposition and closure of the pharyngeal wallat
the end of the procedure and encourage complete pri-
mary healing. Nasogastric feeding continues for 5 post-
operative days, and if the wound is healthy and the pa-
tient can swallow, per oral nutrition may commence.
Wound healing may be impaired by malignant disease,
immunosuppressants, cytotoxic drugs, and steroids.
2.
CSFleakage and meningitis This may occur with exces-
sive manipulation of the dura or damage to pharyngeal
tissues, preventing complete closure of the wound and
thus creating a fistula.
3., Hematomaformation may lead to infection and wound
breakdown. Meticulous control of venous bleeding is
required during closure.
4.
Velopharyngeal dysfunction results in a nasal tone of
voice, nasal regurgitation,
and dysphagia. Excessive
scarring of the soft palate and pharynx has been impli-
cated
as a cause
for this
difficult
physiological
problem.23
5. Dysphagiaandnasalregurgitationmayalsooccurdue
to anatomical changes after division of the palate or
tongue in extended transoral procedures. This can be
corrected by the insertion of palatal implants or plates.
6.
Dental malocclusion may occur when the maxilla or
mandible are divided. Minor malalignments can self-
correct with time.
7.
Painand stiffness of thejaw may be overcome by early
physiotherapy.
8.
Craniovertebralinstability The complex biomechanical
properties of the CC]require not only decompression
and excision of the abnormal tissue but also simultane-
ous stabilization with instrumentation.
9.
Dislocation of the mandible Always check that the
mouth closes satisfactorily at the end a procedure.
.
Conclusion
The transoral approach, with extended variations, is effec-
tive in exposing midline pathology
from the clivus to
C3- C4.The approach is most commonly used for tumors
such as chordomas and chondrosarcomas, and in rheuma-
toid disease. A thorough knowledge of the anatomy and
physiology of the CC]is required for safe surgery and the
avoidance of complications. Details of odontoidectomy,
tumor resection, and wound closure are discussed further
in Chapters 6, 7,and 8.
n__".
____

References
5
TransoralApproaches to the Craniocervical Junction: General Principles
59
1. Crockard HA.The transoral approach
to the base of the brain and up-
per cervical cord. Ann R Coli Surg
EngI1985:67:321-325
Ia. Kanaval AB.JAMA 1909:53:1704-1707
lb. Greenberg
AD. Scoville
WB. Davey
LM. Transoral
decompression
of
atlantoaxial
dislocation
due
to odontoid
hypoplasia.
Report
of two
cases.J Neurosurg
1968;28(3):266-269
Ie. Grison C. Direct surgical
approach
by oral
route
to the
first
2 cervical
vertebrae.
J
Fr
Otorhinolaryngol
Audiophonol
Chir
Maxillofac
1967:16(4):271-273
leLMenezes AH. Van Gilder
JC. Graf CJ. McDonnell
DE. Craniocervical
ab-
normalities.A comprehensive surgical approach. J Neurosurg
1980;53(4):444-455
Ie. Scoville WB. Sherman
IJ. Platybasia.
report
of 10 cases
with
com-
ments on familial
tendency.
a special
diagnostic
sign.
and
the
end
re-
sults of operation.
Ann Surg
1951; 133( 4):496-502
If. Fang HS. Ong GB. Direct
anterior
approach
to the
upper
cervical
spine.
J BoneJoint Surg Am 1962;44A:1588-1604
2. Crockard HA. Johnston
F. Development
oftransoral
approaches
to le-
sion of the skull
base
and
craniocervical
junction.
Neurosurgery
Q
1993;3:61-82
3. JamesD.CrockardHA.Surgicalaccess to the base ofthe skull and up-
per cervical spine
by
extended
maxillotomy.
Neurosurgery
1991;29:411-416
4. Vishteh AG. Beals SP. Joganic
EF. et al. Bilateral
sagittal
split
mandibu-
lar osteotomies
as an adjunct
to the
transoral
approach
to the
ante-
rior craniovertebral
junction:
technical
note.
J Neurosurg
Spine
1999;90:267-270
5. RockPJ.Tomecek FJ. Ross L. Transoral
surgery:
an anatomic
study.
SkullBaseSurg 1993:3:109-116
6. LabordeG.Gilsbach J. Bertalanffy H. Harders
A. Harmack
M. Limits of
thetransoral approach in craniospinal
malformations.
Skull Base Surg
1992;2:6-10
7. CrockardHA.Sett p. Geddes JF. Stevens JM. Kendall
BE. Pringle JAS.
Damagedligaments at the craniocervical
junction
presenting
as an
extraduraltumor: a differential
diagnosis
in the elderly. J Neurol Neu-
rosurgPsychiatry 1991;54:817-821
8. TuiteGF.Crockard HA. On the use of lateral surgical
approaches
to le-
sionsat the craniovertebral
junction.
Neuro Orthopaed
1995; 17/18:
47-56
9. CrockardHA.Koksel T. Watkin N. Transoral
transclival
clipping
of an-
terior inferior cerebellar aneurysm
using new rotating
applier. J Neu-
rosurg1991;75:483-485
10.
Casey ATH. Crockard
HA. Geddes JF. et al. Vertical translocation:
the
enigma
of the disappearing
atlantodens
interval
in patients
with
myelopathy
and
rheumatoid
arthritis.
I: Clinical.
radiological
and
neuropathological
features.J
Neurosurg
1997;87:856-862
11.
Menezes
AH. Pathogenesis
dynamics
and management
of Os odon-
toideum.
Neurosurg
Focus 1999;6: Article 2
12.
Crockard
HA. Heilman
AE. Stevens
JM. Progressive
myelopathy
to
odontoid
fractures:
clinical.
radiological.
and
surgical
features.
J
Neurosurg
1993;78:579-586
13.
Harkey HL.Crockard
HA. Stevens JM. Smith R. Ransford AO. The oper-
ative management
of basilar
impression
in osteogenesis
imperfecta.
Neurosurgery
1990;27:782-786
14.
Bhangoo RS. Crockard HA. Transmaxillary
anterior
decompressions
in
patients
with
severe
basilar
impression.
Clin
Orthop
1999;359:
115-125
15.
Sen CN. Sekhar
LN. Schramm
VL. Janecka
IP. Chordoma
and chon-
drosarcoma
of the cranial
base: an 8-year
experience.
Neurosurgery
1989;25:931-941
16.
Keogh S. Crockard
HA. Staphylococcal
infection
of the odontoid
peg.
postgrad
MedJ 1992:68:51-54
17.
Meyer FB. Ebersold
MJ. Reese OF. Benign tumors
ofthe
foramen
mag-
num.J
Neurosurg
1984;61:136-142
18.
Harkey HL. Crockard
HA. Transoral-extended
maxillotomy.
In: Dick-
man CA.Spetzler
RF.Sonntag
VH. eds. Surgery of the Craniovertebral
Junction.
New York: Thieme:
1998:371-381
19.
May DM. Jones
SJ. Crockard
HA. Somatosensory
evoked
potential
monitoring
in cervical
surgery:
identification
of pre- and intraopera-
tive risk factors associated
with neurological
deterioration.
J Neuro-
surg 1996;85:566-573
20.
Marks Rj. Forrester
PC. Calder I. et al. Anaesthesia
for transoral
cranio-
cervical surgery. Anaesthesia
1986;41: 1049-1054
21.
Casey ATH. Crockard
HA. Bland JM. Stevens J. Moskovich
R. Ransford
A. Predictors
of outcome
in the quadriparetic
nonambulatory
myelo-
pathic
patient
with rheumatoid
arthritis:
a prospective
study of 55
surgically
treated
Ranawat
Class
IIIb
patients.
J
Neurosurg
1996:85:574-581
22.
Casey ATH. Crockard
HA. Stevens J. Vertical
translocation.
II: Out-
comes
after surgical
treatment
of rheumatoid
cervical
myelopathy. J
Neurosurg
1997:87:863-869
23.
Tuite GF.Veres R. Crockard HA. Sell D. Pediatric
transoral
surgery:
in-
dications.
complications.
and
long-term
outcome.
J Neurosurg
1996;84:573-583

6
Transoral Odontoidectomy
David Choi and H. Alan Crockard
.
Indications
.
Contraindications
.
Advantages
.
Disadvantages
.
Objectives
The most common indication for transoral
surgery is
pathology of and around the odontoid process causing ven-
tral neuraxial compression.1.2In the previous chapter we
discussed the indications for transoral odontoidectomy as
well as the pathologies that may be encountered. In this
chapter we discuss further the surgical techniques for the
removal of the odontoid process.
.
Indications
.
Ventralcompressionofthe cervicomedullaryjunction
byrheumatoidpannusortumor
.
Odontoidfracture and irreduciblesubluxationcausing
ventralcompressionofthe cord
.
Contraindications
.
Oral sepsis
. Inabilityto open the mouthmorethan 25 mm (see
Chapter5)
.
Fixedflexion deformity of the neck,resulting in poor
surgical access
. Farlateral pathology
.
Advantages
. A direct ventral approach is the most appropriate for
pathology of the odontoid process that does not extend
beyond 15 mm of the midline.
.
The approach is safe within the defined boundaries.
60
.
Radiological
Evaluation
.
Surgical Techniques
Insertion ofTransoral Retractor
Midline Posterior Pharyngeal
Incision
Odontoid Resection
.
Outcome
. Enablesvisualization of bony margins to be resected
.
Enablesresectionofcompressivesofttissuemasses
.
Disadvantages
.
Adeep and narrow working space
. Risk of cerebrospinal
fluid (CSF) leakage (see Chap-
ter 8)
.
Requiresa secondstageposteriorstabilization
.
Riskofspinalcordinjury
.
Riskofinjurytovertebralartery in lowapproaches
.
Objectives
It is important to appreciate the angle at which the transo-
ral surgeon approaches the upper cervical spine and clivus,
which can vary considerably in severe basilar invagination
and pediatric cases. This has implications for choosing
the most appropriate route: simple transpharyngeal odon-
toidectomy, transpalatal extension, or extended maxillo-
tomyjmandibulotomy. The surgeon needs to be aware ofthe
altered anatomy and stability of the craniocervical junction
(CCJ)to performsaferemovalofthe odontoidprocess.Pre-
operative imaging is crucial for this objective.
.
Radiological Evaluation
Each patient undergoes plain cervical x-rays in flexion and
extension.3 Computed tomography, including bone-win-
dow images with 1 mm slice thickness and three-dimen-

sional(3D)reconstructions,provides essential information
abouttheoccipitoatlantoaxialcomplex.The most common
radiologicalabnormality in rheumatoid
patients
is ventral
subluxationof the atlas.4 An anterior atlantodental
interval
ofgreater than 5 mm indicates
rupture
or attenuation
of
thealarligaments as well as the transverse
ligament;
there
areno grades of instability.
In children,
especially
those
withlax ligaments,S mm may be acceptable.
A lesion
is
consideredto be irreducible
when traction
or changes
in
headposition do not produce
realignment
of the cervi-
comedullaryjunction nor relieve compression.
Magnetic
resonanceimaging (MRI) is essential.
Dynamic
MRI will
demonstratethe compressive
effects
of the
underlying
pathology.5
. SurgicalTechniques
. For uncomplicated
cases
nasotracheal
intubation
is
used.
. Themouth, tongue, and palate are coated with
1%
hydrocortisoneointment.
InsertionofTransoral Retractor
Thetransoral retractor
(Crockard
transoral
instruments,
Codman Raynham, MA, USA) is inserted
with
a tongue
bladeofsuitable length, retracting the tongue and mandible
caudallywith rostral countertraction
being applied
to the
upperalveolarmargin.Swelling of the tongue and lip can
beavoidedby careful placement
of the retractor.
A small
bolster,such as a rolled-up
towel, is placed
between
the
handleofthe retractor and the sternum to allow further ex-
posurebelow the arch of C1.The soft palate and uvula are
retractedusing the curved retractor
blade attached
to the
transoralretractorframe.The right-angle retractor is used
toretractthe nasotracheal and nasogastric
tubes out of the
operativefield(see Chapter 5, Fig. 5- t).
MidlinePosterior Pharyngeal Incision
Theposterior pharyngeal wall is infiltrated
with 1% lido-
cainewith 1:200,000 epinephrine. A 3 cm longitudinal
midlineincision is made in the posterior
pharyngeal
mu-
cosausinga knife;monopolar diathermy is used to incise
tissuesdeepto the mucosa (Fig. 6- t). The key to surgical
orientationisfirstto identifyand incise over the tubercle of
theatlasand then to continue the incision in a cephalad
or
caudaddirection depending on the location of the underly-
ing pathology.
Thepharyngealretractor is inserted and opened to spread
thepharyngealmucosa laterally, revealing
the underlying
tubercleof the atlas, the attachments
of the longus coIli
muscleson either side, and the anterior
longitudinalliga-
ment through a hexagonal-shaped
window.
Cutting
diathermyand a periosteal
elevator
are used to carefully
dissectthesetissues laterally off the anterior surface of the
vertebra(Fig.6-2). At this stage it is important to identify
the(1-(2 interspace,anterior tubercle of the atlas, caudal
6
Transoral Odontoidectomy
61
L
Figure 6-1
Operative viewofthe 50ftpalate and posterior pharyn-
gealwall.The incisioninthe soft palate and the posterior pharyngeal
mucosaare indicatedbybrokenlines.
edge of the clivus, and odontoid peg, as well as delineating
the lateral boundaries of subsequent bone removal. If the
anatomical landmarks are distorted it is helpful to use neu-
ronavigational techniques or intraoperative fluoroscopy to
confirm orientation.
Figure 6-2
Atransoral viewof the (1-(2
complex after the inser-
tion ofpharyngealretractors. Identificationofthe anterior tubercle of
the atlasiscrucialbeforethe removalofbone.

62
OccipitocervicalJunction:AnteriorApproach
A long, angled, high-speed drill with a side-cutting,
match-head bur is used to remove cancellous bone and sub-
sequently cortical bone. The limits of bone removal can be
assessed by direct inspection with the operating micro-
scope or with indirect methods (neuronavigation or fluo-
roscopy). It is possible to remove only part of the anterior
arch of C1 while sufficiently exposing the odontoid peg.
Then the remainder of the bone, as well as remnants of
soft tissue at the base of odontoid process, can be removed
(Fig.6-3).
Injury of the vertebral artery is possible when the bony
resection is continued
down to the C2- C3 interspace,
where the artery can lie less than 10 mm from the midline.
In odontoid fractures part or all of the transverse ligament
may be interposed between the fragments of bone. Careful
attention to the position of the transverse ligament will al-
low optimum planning ofthe surgical approach.
Odontoid
Resection
The odontoid grasping forceps are used to hold the peg
while the drill is used simultaneously to thin the base of the
odontoid (Fig.6-4). Remnants of ligament and fibrous tis-
sue are removed with pituitary rongeurs and Kerrison up-
cuts. Great care must be taken when the ligaments are cal-
cified.
Sometimes
in
elderly
patients
periodontoid
pseudotumor
(amorphous
friable connective tissue) is
noted and is associated with pathological movement of the
joint.6 Rheumatoid patients wfth basilar invagination typi-
cally have noncalcified reactive granulation tissue (rheuma-
toid pannus) around the odontoid process. This tissue must
be excised. The dura mater will then prolapse forward and
is seen to pulsate.
It is at this stage of the operation that dural tears are
likely to occur, particularly with an extremely translocated
Figure 6-3
Partial removalof the anterior arch of (1 and sufficient
exposure of the odontoid peg.
r
Figure 6-4
Operative viewafter the total removal of the anterior
archofthe atlasand completeexposureofthe odontoid process.
odontoid peg. With the help of small dissectors a "plane de
cleavage"betweensoft tissue massesand underlyingdura
is carefully developed. In congenital basilar invagination or
in severe cases of rheumatoid arthritis with vertical translo-
cation of the odontoid process, the anterior rim of the fora-
men magnum may need to be removed to allow extraction
of the migrated odontoid. This maneuver will almost cer-
tainly require division of the soft palate to provide adequate
superior exposure.
. Outcome
After odontoidectomy, instability is assumed and therefore
one should be prepared for posterior fixation or application
of a Halo vest? This is commonly required after the decom-
pression of rheumatoid
pannus, with chronic traumatic
fractures and pseudotumor
formation, and pathological
changes of the CC].Stabilization may be performed on the
same day or on a separate occasion.8-11It is important to ap-
preciate that in rheumatoid arthritis a fixed degenerate
joint is not a stable joint and might be compared with the
instability of an impacted femoral fracture, which requires
fixation.

References
6
TransoralOdontoidectomy
63
1.
Menezes
AH.
Van Gilder jc. Transoral-transpharyngeal
approach
to
the anterior
craniocervical
junction:
ten-year
experience
with
72
cases.j Neurosurg
1988:69:895-903
l
Hadley MN. Spetzler
RF. Sonntag VKH. The transoral
approach
to the
superior cervical spine:
a review
of 53 cases
of extradural
cervi-
comedullary compression.j
Neurosurg
1989:71:
16 - 23
3. Prescher A. Bros D. Adam
G. Anatomic
and radiologic
appearance
of
several
variants
of
the
craniocervical
junction.
Skull
Base
Surg
1996;6:83 - 94
4. Crockard
HA. Surgical management
of cervical rheumatoid
problems.
Spine
1995;20:2584-2590
5. Crockard HA. Heilman
AE. Stevens
jM.
Progressive
myelopathy
secondary
to odontoid
fractures:
clinical.
radiological
and
surgical
features.j Neurosurg
1993:78;579-586
6. Crockard HA. Sett P. Geddes jF. Stevens jM.
Kendall
BE. Pringle JAS.
Damaged ligaments
at the craniocervical
junction
presenting
as an
extradural
tumour:
a differential
diagnosis
in the elderly.
j Neurol
Neurosurg
Psychiatry
1991 ;54:817-821
7.
Dickman CA. Locantro j. Fessler RG. The influence
of transoral
odon-
toid resection
on stability of the craniovertebral
junction.
j Neurosurg
1992;77:525-530
8.
Crockard HA.Pozo jL. Ransford AO.et al. Transoral decompression
and posterior
infusion
for rheumatoid
atlanto-axial
subluxation.
j
Bone joint Surg Br 1986;68:350-356
9.
Crockard
HA. Calder I.Ransford AO. One-stage
transoral
decompres-
sion and posterior
fixation
in rheumatoid
atlanto-axial
subluxation.
j
Bonejoint
Surg Br 1990:72:682-685
10. Naderi S. Crawford NR. Melton MS. Sonntag VK.Dickman CA.Biome-
chanical
analysis
of cranial
settling
after transoral
odontoidectomy.
Neurosurg
Focus 1999:6:7
11.
White M. Panjabi
MM. The clinical
biomechanics
of the occipitoat-
lantoaxial
complex. Orthop Clin North Am 1987:9:867-878

7
Extended Transoral Procedures and Midline
IntraduralTumor Resection
David Choi and H. Alan Crockard
.
Indications
.
Advantages
.
Disadvantages
.
Surgical Techniques
Anesthesia
Rostral Extension: The "Open-Door" Maxillotomyll.12
At first glance. a transoral approach would seem appropriate
for intradural midline tumors that are ventral to the brain
stem and the cervical cord. This, however. is not usually the
case; there is limited lateral access and a high risk of cere-
brospinalfluid(CSF)leakageand meningitis.Wetherefore
do not advocate elective primary intradural surgery via the
transoral route, unless all other approaches have been dis-
counted.! Butfor extradural tumors that have penetrated the
dura we are quite prepared to accept the risks of the transo-
ral approach because a larger amount of a ventral tumor can
be removed by this route compared with an infratemporal
or suboccipital approach. Atwo-stage, far lateral and transo-
ral approach may be used for extensive tumors.2,3Interest-
ingly.the infection rate for transoral operations in our expe-
rience is similar to lateral and posterolateral approaches.4-7
General considerations and pathology have already been
covered in Chapter 5.Here, we concentrate on surgical tech-
nique alone.
.
Indications
In addition to factors discussed in Chapter 5. for an ex-
tended approach the following need to be considered:
.
The primary location and origin of the lesions
.
Whether it is benign or malignant
.
The direction of compression and lateral extension
.
The relationship of the lesion to the major arteries
.
Advantages
Lateral approaches to the clivus. foramen magnum. and an-
terior brain stem have been described by many authors.9.!O
The extended transoral route has the following advantages:
64
Caudal Extension
Intradural Surgery14
.
Complications
Intraoperative
Postoperative
. Direct
exposure of the clivus without obstruction by cra-
nial nerves or vessels
. A safe approach. within the defined boundaries of the
clivectomy
.
Better access to ventral midline lesions. especially inthe
middle and upper thirds of the clivus
. Goodaccessto extradurallesions arising fromthe
clivus.with secondary midline intradural invasion
.
Disadvantages
The transoral route to intradural pathology has several
disadvantagescomparedwith lateraland posterolateralap-
proaches:
. Poor proximal and distal control of the vertebral artery
and its branches
.
Poorexposureofthe cranialnerves
.
Potentialcontaminationofthe sterileintracranialcom-
partmentbyfloraofthe oropharyngealcavity
Selection of the most appropriate surgical approach de-
pends on the location ofthe
lesion2:
.
Forthe upper third of the clivus a subtemporal cran-
iotomy with optional anterior petrosectomy is recom-
mended.
.
For lesions of the upper and middle thirds of the clivus,
a subtemporal craniotomy or a combined supratentorial
and infratentorial approach with a posterior petrosec-
tomy is appropriate.
.
Forthe middle and lower thirds of the clivus.a far lateral
approach with posterior petrosectomy is recommended.

7
Extended Transoral Procedures and Midline Intradural Tumor Resection
65
. Forthe entire clivus, a far lateral and/or combined
supratentorialand infratentorial approach including
posteriorpetrosectomyshould be performed.
. SurgicalTechniques
Anesthesia
Althoughnasotrachealintubation is the norm for classic
transoralsurgery.it is our practice to perform an elective
tracheostomyforextensivetumors. Systemic monitoring is
performedby use of an arterial line (blood pressure can
changedramaticallyduring the manipulation of intradural
tumorscloseto thebrain stem). a central venous line. a Fo-
leycatheter,electrocardiography,and a pulse oximeter.
If thereisa possibilityof dural breach a lumbar spinal
drainisinsertedforcontinuous CSFdrainage (10-15 mL/h)
andremainsin situ foraround 5 days after the operation or
issometimesconvertedto a lumboperitoneal shunt in cases
ofpersistent(SFleakage.
Anelectivepercutaneousgastrostomy tube is inserted for
perioperative
gastricdrainageand postoperative feeding.
RostralExtension:The "Open-Door"
Maxillotomyll.12
Operative
Stages
1. Anorizontalincision(LeFort Imucoperiosteal incision)
is madeabovethe mucogingival reflection from one
maxillarytuberosity to the other (Fig. 7-1). The maxil-
larybuttressesandthe bone above the dental apices are
exposedandthe face is degloved until the nasal aper-
tures,floor. and septum are visible. At this point the
cartilaginousseptum is detached
and
the vomer
reflected laterally. Excessive detachment
of the
mucoperiosteumshould be avoided to maintain the
bloodsupplyto the maxilla. The dental apices should
beidentifiedon the preoperative orthopantomogram to
avoidrootinjuries(Fig. 7-2).
Figure7-1
The mucoperiosteal incision for exposure of the maxil-
larybuttresses.
""\
\
/'
/
Figure 7-2
Operative photograph showingthe complete mucogin-
givalincisionand the detachment ofthe mucoperiosteum.
2.
Preciserelocation of the maxilla after osteotomy is es-
sential to avoid postoperative malocclusion. Tothis end,
titanium miniplates are contoured and held in position
with screws around the maxillary buttresses and the
prespinal area before cutting the bone with a sagittal
saw (Fig. 7-3). Two additional miniplates are inserted
posteriorly for rigid three-point fixation. The miniplates
are then removed and carefully marked prior to making
the saw cuts.
3.
The LeFort I osteotomy cut is made with an air pow-
ered reciprocating saw. passing along one side of the
vomer and between the two incisors. close to the mid-
line (Fig. 7-4). Careful separation of the nasal septal
mucosa is essential to avoid damage; this mucosa can
be flapped posteriorly to aid mucosal closure if the dura
has been breached (Fig.7-5). Amidline sagittal incision
is made
in the oral mucosa
and palatal
muco-
periosteum, which is reflected back a few millimeters.
along the line of the hard palate osteotomy.
4.
The hard and soft palate are divided and both halves of
the upper jaw are reflected laterally. The maxillary
tuberosities are separated from the pterygoid plates
with a curved osteotome and the two halves of the
maxilla are separated and swung inferiorly and laterally
(Fig.7-6). The vomer can be removed to expose the an-
terior sphenoid sinus. The separation of the two halves
is completed by dividing the soft palate initially in the
midline but deviating to one side of the uvula posteri-
orly (Fig. 7-7). Special care is taken to avoid damaging
the palatal mucoperiosteum and the remaining connec-
tions to the pharynx to preserve the blood supply to
each maxillary segment. Because the neurovascular ar-
cade is well developed in the maxillary alveolar bone.
the circulation to the anterior upper teeth is preserved
even when the descending palatine arteries are cut.
However. it is advisable to preserve the descending
palatine
arteries
in patients
who have previously
received irradiation or intra-arterial chemotherapy.

66
OccipitocervicalJunction:AnteriorApproach
..,.......
A ,
,--1'..
\ --~(
""~. ~_
_ _
.
I
-/
-
B
Figure7-3
(A) Operative photograph showing the location of the contoured titanium mini-
plates before maxillotomy.(8) Schematicdrawingofmaxillotomywitha reciprocatingsaw.
Figure 7-4
The le Fort Iosteotomy and representation
of the midline split of the soft and hard palate.
B
",
Figure 7-5
Operative photograph
showing the careful separation of
nasal mucosa.
I
r~~
I
Figure 7-6
After splitting the maxilla. the two halves are separated
and mobilized inferiorly and laterally.

7
Extended Transoral Procedures and Midline Intradural Tumor Resection
67
U
r-r'
Figure7-7
(A) The splittingofthe soft palate and lateralretraction of both halves.(8) Operative
photograph of soft
palate
splitting.
B
5.Thetransoralretractor and the specially designed mid-
facialosteotomy retractor plate are inserted (Crockard
transoralinstruments, Codman, Raynham MA, USA).
Themaxillotomy plate is applied to the upper gum
guardon'the transoral retractor to provide countertrac-
tionagainstthe cut surface of the maxilla.The hard
palateretractor is positioned to hold the maxillary seg-
mentsout of the operative field revealing the posterior
nasopharynx from the sphenoid sinus to the upper cer-
vical spine (Fig.7-8).
6.
Exposure of the clivus and the craniocervical joint
(CCJ)is achieved through a midline mucoperiosteal
incision that should extend well above and below
the level of the lesion.The pharyngeal muscles and mu-
cosa over the clivus are retracted laterally by using
monopolar
diathermy
and a periosteal
elevator. A
Figure 7-8
The positioning of the hard palate retractor
and lateral displacement of the maxillarysegments. Note
the midlinepharyngealincisionand the underlyinganatom-
icalstructures: clivus,anteriorarchof(1 and (2.

68
Occipitocervical Junction: Anterior Approach
pharyngeal retractor is then inserted to retract the soft
tissue. The rostrocaudal anatomical landmarks (sphe-
noid-clivus-arch of Cl-body of C2)as well as the lat-
eral borders (lateral walls of the sphenoid sinus-medial
edges of the foramen lacerum-medial
surfaces of the
occipital condyles-lateral
masses of atlas and axis), in
addition to the previously described important midline
landmarks, should be clearly identified before proceed-
ing with bone removal. Gentle handling of the pharyn-
geal tissues is necessary to keep the edges of the mu-
cosa healthy, thus allowing good wound closure (Fig.
7-9).
7.
The bone is removed using a high-speed drill with a
3 mm side-cutting (match-head) bur for the cortical
bone, and once all the bone is thinned appropriately,
the remaining shell is removed using Kerrison upcuts
(1 mm and 2 mm footplates). The cIivalbone is thinned
down and excised from anterior to posterior to meet
the foramen magnum, taking care to leave the poste-
rior cortical surface of the clivus and odontoid intact.
Next, the deeper cortical bone is removed to reveal the
dura. Significant hemorrhage from venous channels
may be encountered during dissection of the rostral
clivus. In most situations, Surgicel and bone wax will
control bleeding from the epidural space and bone,
respectively.
Figure 7-9
Operative photograph
after the final placement of retrac-
tors and wide exposure of the preclival area and atlantoclival junction.
Caudal Extension
Median Mandibu/otomy and/or G/ossotomyl3
Acaudal extension is useful in some patients who requirea
transoral approach to pathology at the CCJ.This may apply
to patients who have:
.
Limited mouth opening due to rheumatoid arthritis in
the temporomandibular joint
.
Craniofacial and intraoral anomalies (macroglossia, mi-
crognathia, retrognathia) that limit the space for ante-
rior neuraxial decompression
. Tumor at the CCJwith caudal extension (rostrocaudal
tumor length of 60 mm or more)
Operative Stages
1.
Atracheostomy is performed prior to extended transoral
surgery. The head is fixed in a three-pin fixation system
2.
The labial incision starts at the lower lip and, strictlyfol-
lowing the midline, extends inferiorly to the hyoid bone.
In the mouth the mucosal incision extends to the lower
buccal sulcus, in front of the mandibular origin of the
genioglossus and geniohyoid muscles, and the frenulum
of the tongue. By keeping to the midline there is less
chance of damaging the lower segment of the orbicu-
laris oris muscle, therefore maintaining normal postop-
erativefunctionofthe lowerlip.Theincisiononthechin
may be Z shaped for a more cosmetic scar (Fig.7- to).
3.
The mandibular periosteum is incised and detached for
1 cm on either side of the midline to create room for
the osteotomy. This is performed in the midline be-
tween the central incisors using a reciprocating saw
and completed with thin osteotomes. Extensive lateral
exposure of the periosteum is undesirable because this
may damage the mental cutaneous branches of the
mandibular nerve (V3), which are essential for sensa-
tion in the lower lip (Fig.7-11).
4.
Prior to a midline mandibular osteotomy one or two tita-
nium plates are shaped to approximate the curves ofthe
anterior surface of the mandible and fixed temporarily
with screws. After the holes are demarcated and drilled,
the plate is removed. This initial planning helps to accu-
rately relocate the mandible at the end of the procedure
and avoids malocclusion of the teeth. The plates should
be placed below the root apices ofthe teeth (take noteof
the preoperative orthopantomogram).
5.
While the mandibular halves are freed and swung later-
ally,dividing the lingual frenulum and the genioglossus
and geniohyoid muscles creates more space. In the
rheumatoid patient, the intact tongue may be retracted
down out ofthe operative field without the need to di-
vide it.
6.
The median glossotomy is performed using monopolar
cutting diathermy, allowing exposure as far down as (4.
The tongue is split in the midline down to the anterior
border of the vallecula and epiglottis. The halves of the

7
Extended Transoral Procedures and MidlineIntradural Tumor Resection
69
.........
"
Ar -
I
L
':4.':(.h;;,j.;,~
-;. r;:~"';j),._.
B
Figure7-1 0
(A) Photograph showing the incision for the median mandibulotomy
approach (inferior extension
to the hyoid bone). (8) Photograph
showingthe complete extent of the operative
incision.
tonguearespreadlaterally and held in place by self-re-
tainingretractors.With careful division of the tongue in
themidline,injury to the lingual arteries, hypoglossal
nerves,styloglossus,hyoglossus. and mylohyoid mus-
cles(significant parts of the floor of the mouth)
is
avoided(Fig.7-12).
Afterthisstagewe follow the same steps as the maxilIo-
tomyapproachwith special attention to the midline land-
marksthatarecrucial for safesurgery. Retraction is possible
downtotheinferior aspectof (2 and the (2-(3
disk space.
Withmedianglossotomythe (3 body and even (4 are visible.
IntraduralSurgery14,15
Theextendedtransoralapproachis only suitable for removing
theintraduralspreadof an extradural tumor. The exact ap-
proachistailoredto the individual patient depending on pre-
operativeimaging,variations in anatomy, and the degree of
tumorextension.If necessary,the approach can be extended
rostrallyvia"open-door"maxillotomy (exposingthe sphenoid
sinus)orcaudallyvia median mandibulotomy and/or glosso-
tomy(exposingdown to (3). In the majority of casesthe clas-
sictransoralroutewith splitting of the palate is sufficient.
PatientPositioning
Alumbardrain is inserted prior to surgery. The patient is
placedinasupineposition with lateral tilt of the operating
table.Theheadis stabilized in a slightly extended position
usingathree-pinheadrest.The oral cavity is prepared with
Figure 7-11
Operativeview after the midline mandibulotomy and
splitting of soft tissues.

70
OccipitocervicalJunction:AnteriorApproach
A L..
--
A"
B
Figure 7-12
(A) Operative photograph showing the midline glossotomy. (B) View of the posterior pharyngeal wall after midline glossotomy and
splitting of floor of the mouth.
0.5% aqueous chlorhexidine
solution, and 1%hydrocortisone
ointment
is applied.
of the divectomy.
In cases of malignant
invasion the dura is
excised at the margins of dival exposure.9.IS-17
Dural Opening
Careful Dural Closure
The opening of the dival dura begins in the midline at the
level ofthe tumor and extends laterallybelow the main bulk
of the pathology (cruciate or T-shaped incision) (Fig. 7-13).
Thisexposureallowsthe dura to be retractedbackto the edges
Either nasal septal flaps, a dermal fat graft, or fibrin glueI
(Tisseal Biobond, Immuno
AG, Vienna, Austria)
is used to
repair the dural defect, together with CSFdrainage. (For
details see Chapter 8.)
Figure 7-13
Clivectomy
(upper circle) and dural incfl
sion. Note the underlying
large intradural
tumor thall
distorts
the vertebrobasilar
junction
(lower circle).

7
ExtendedTransoralProceduresand Midline IntraduralTumor Resection
71
. Complications
Postoperative
Intraoperative
. Vertebralandanterior spinal artery injury Injury may
occurduringbone resection at the level of the C2fora-
mentransversarium, or intradurally
when
tumor
en-
velopesthe vessels. Arteries
may be displaced
away
fromtheirnormalposition by tumor.
. Basilarartery injury This artery may follow a helical
coursein previously irradiated patients (due to scar tis-
sueand a diseased arterial wall), and may be damaged
duringdural opening and tumor resection.
. Cranialnerveinjury The lower CNIX,X, XI,XIIare at
greatest risk of injury during
transoral
surgery,
and,
rarely,the upper CN VI, VII, and VIII. Intraoperative
monitoringof CNXthrough XII is useful in reducing the
possibilityof nerve injury. Remember, it is unlikely that
patientspresentingwith cranial nerve deficits will re-
coverfunction after surgery, and partial
deficits
may
wellbecomeworse, at least temporarily.
.
Brainsteminjury Thiscan occur either by injury to per-
foratingarteries or by direct injury to the brain stem
whenthere is scar tissue and lack of arachnoidal
planes.
References
1. Tuite GF.Crockard
HA. On the use of lateral
surgical
approaches
to
lesions at the craniovertebral
junction.
Neuro-Orthopedics
1995;
17'18:47-56IplJ(p21
2. Baldwin HZ. Miller
CG. Van Loveren
HR. Keller
JT. Daspit
CPoSpetzler
RF.Thefar lateral/combined
supra-
and infratentorial
approach:
a hu-
mancadaveric prosection
model
for routes
of access to the petrodival
regionand ventral brainstem. J Neurosurg
1994;81 :60- 68
1
CrockardHA. Transdival
surgery
leditorial].
Br J Neurosurg
1991 ;5:
237-240
4. ColliB.AI-Mefry O. Chordomas
of the craniocervical
junction:
follow-
up review and prognostic
factors. J Neurosurg 2001 ;95:933-943
5. Roberti F. Sekhar
LN. Kalavakonda
C. Wright
DC. Posterior
fossa
meningiomas:
surgical
experience
in
161
cases. Surg
Neurol
2001 :56:8-20
6. CrockardHA.CheesemanA. Steel T. et al. A multidisciplinary
team
approachto skull base chondrosarcomas. J Neurosurg 2001 ;95:
184-189
7. CrockardHA. Steel T. Plowman
N. et al. A multidisciplinary
team
ap-
proachtoskull basechordomas.JNeurosurg 2001;95:175-183
8. CrockardHA.SenCN.The transoral approach for the management of
intraduralesions at the craniocervical
junction:
review of 7 cases.
Neurosurgery
1991 ;28:88
-97
9. BabuRP.Sekhar LN. Wright
DC. Extreme
lateral
transcondylar
ap-
proach:technical improvements
and lessons
learned.
J Neurosurg
1994:81:49-59
.
[SFleakage LumbarCSFdrainage and the use of a fascia
lata or dermal fat graft and fibrin glue are recom-
mended. Careful reapproximation of the muscle layers
is also important.
.
Wound infection The risk of infection increases when
there has been previous surgery or radiation therapy,
and with a persistent CSFleak. Poor wound healing due
to excessive retraction or diathermy of the muscle lay-
ers and poor mucosal closure also contribute adversely.
.
Velopharyngeal
incompetence
This
difficulty
in swal-
lowing and speaking occurs more commonly in pa-
tients with intradural tumors due to more extensive
bone removal, which increases the likelihood of injury
to the soft palate and the posterior pharyngeal wall. It
probably results from removal of the bony support of
the dorsal pharynx and should be distinguished from
dysphagia and dysphonia secondary to cranial nerve
palsies.
.
Instability of the spine Instability is probably related to
the disruption of the anterior bony and ligamentous
structures at the CC],and a posterior fusion may be re-
quired at a second stage.
10. Meyer FB.Ebersold MJ.Reese DF.Benign tumors of the foramen mag-
num.J Neurosurg 1984;61:136-142
11. Harkey HL. Crockard HA. Transoral-extended
maxillotomy.
In: Dick-
man CA.SpetzlerRF.SonntagVH,eds.Surgeryof the Craniovertebral
Junction. New York: Thieme; 1998:371-381
12. James D. Crockard HA. Surgical accessto the base of the skull and up-
per cervical
spine by extended
maxillotomy.
Neurosurgery
1991;
29:411-416
13. Vishteh AG.BealsSP.Joganic EF.et al. Bilateral sagittal split mandibu-
lar osteotomies
as an adjunct
to the transoral
approach
to the ante-
rior
craniovertebral
junction:
technical
note. J Neurosurg
Spine
1999;290:267-70
14.
Miller
E. Crockard HA. Transoral transdival
removal of anteriorly
placed
meningiomas
at the foramen
magnum.
Neurosurgery
1987:
20:966-968
15. Crockard HA. Bradford R.Transoral transdival removal of a schwan-
noma anterior to the craniocervical junction: case report. J Neurosurg
1985;62:293-295
16.
Uttley D. Moore A. Archer DJ.Surgical management
of midline skull
base tumors:
a new approach.J
Neurosurg
1989;71 :705 - 710
17.
Reilly GO. Crockard HA. Lightman S.James DR. Phillips RH.Smith M.
Excision of a dival and upper cervical pheochromocytoma by an ex-
tended maxillotomy approach: a case report. Skull Base Surg 1993;3:
87-901p6)

8
TransoralClosure
DavidChoi and H. Alan Crockard
. Advantages
. Disadvantages
. Objectives
. SurgicalTechniques
Closureof the Posterior
Pharyngeal
Wall
Avoidanceof Dead Space and Hematoma
Formationinthe Wound Bed
GraftsandPharyngealMucosalFlaps
Lesions-of
the skullbaserequire not only careful exposure
andadequateresection but also meticulous
closure to pro-
tectneuralstructures and restore oropharyngeal
function.
Thischapterconcentrateson wound closure alone.
.
Advantages
. Adequateclosure reduces risk of infection and cere-
brospinal fluid (CSF)leak.
. Meticulousattention to hemostasis avoids complica-
tionsrelated to hematoma formation.
. Disadvantages
. Adequateclosure of the dura may require the harvest of
adermalfat graft from the thigh. However, the advan-
tageofsealing the dura greatly outweighs
the additional
woundon the thigh.
. Objectives
. Toprevent(SF leakage and meningitis
. Toavoiddead space and hematoma formation in the
bedofthe wound
. Useofpharyngeal mucosal flaps may be useful
Maxillotomy Reconstruction:Repairof the Roofof
the Oral Cavity
Mandibulotomy Reconstruction:Repairof the Floor
of the Mouth
. Outcome
Postoperative
Management
PostoperativeAssessmentof BulbarFunctionand
Oral Cavity Dysfunction
.
Anatomicalrealignmentofthe maxillaand mandible
.
Postoperative assessment of bulbar and oral cavity
function
The primary goal of dural repair is to reestablish a barrier
between the intracranial cavityand the oropharyngeal space.
Whereas a prophylactic lumbar drain is placed before the
operation as previously described in Chapter 5, effective
dural reconstruction and prevention of CSFleakage are major
considerations in transoral surgery. This can be particularly
challenging when dura has been resected, creating a large
defect. Suturing dura of the clivus is extremely difficult, and
complications of poor closure can be catastrophic.!
.
Surgical Techniques
After completing tumor resection, the remaining edges of
dura are approximated and Surgicel (Johnson &Johnson,
New Brunswick, NJ,USA)is laid over the dura and defect.
Fibrin glue (Tisseal Biobond, Immuno AG,Vienna, Austria)
provides an immediate seal but has no inherent strength;
ingrowth of fibroblasts is necessary.2
Agraft of fascia lata or fat creates a second layer of clo-
sure, but these are rarely viable in the long term. We now
use a dermal fat graft. created from an ellipse of skin and
underlying fat,with the epidermis removed by shaving with
a scalpeJ.3This fills the defect in the clivus, placed with the
dermis against the dura, from which it will pick up a blood
supply (Fig. 8-1).
Surgicel (Johnson & Johnson,
New
Brunswick, NJ,USA)and fibrin glue may be placed over the
73

74
OccipitocervicalJunction:Anterior Approach
Figure 8-1
Dermalfat graft usedto closea clivaldefect.
graft to hold it in place. It is important to ensure full cover-
age of any potential dural defect and eliminate dead space.
The graft has the additional effect of protecting the neural
structures from subsequent radiation. The pharyngeal wall
is carefully sutured
over this with
interrupted
Vicryl
(Ethicon, NJ,USA)stitches. Ifthe incision is in the posterior
nasopharynx then ribbon gauze (soaked in Whitehead's
varnish[Professional
Dentist Supplies Ltd., Bayeswater,
Ausralia)) is packed via the nose and removed 7 days later
under a light general anesthetic.
Closure of the Posterior Pharyngeal Wall
Below the Foramen Magnum
The longus colli muscles and the pharyngeal musculature
are closedintwo layersusing3-0 Vicrylsutures(Fig.8-2).
Healing of the pharyngeal mucosa is rapid, with inherent
host immunity to normal oral flora. However, pharyngeal
healing may be impaired in patients with rheumatoid
arthritis,
malignancy, previous irradiation, and chronic
steroid or immunosupressive
therapy. Care should be
taken during dissection of tissues and placement of tran-
soral retractors to minimize later complications.4.s Cases
with necrotic tissue or scar due to previous operations or
radiotherapy may require a vascularized mucosal flap (see
following).
AbovetheForamenMagnum
The mucosa in this area is firmly adherent to the bone by
Sharpey's fibers. Evenwith the most careful dissection it is
Figure 8-2
The muscle layer below the foramen magnum is approxi.
mated first and the mucosa as a second layer.
difficult to maintain integrity of the mucosal flap, especially
superiorly.Heresingle-layerclosureand,ifnecessary,nasal
septal mucosal flaps are used (see following).
Avoidance
of Dead Space and Hematoma
Formation
in the Wound Bed
To avoid complications,
the following should be noted:
. Meticuloushemostasisof any epidural bleedingor
bleeding from venous sinuses or cut bone surfacesis
required. Surgicel or Avitene may be used when appro-
priate.
.
Carefulapplicationofthe graft intothe dural-clivalde-
fect, with fibrin glue
.
Ensureappositionofmucosaeandboneofthe nasalsep-
tum, posterior portion of the hard palate, and floorofthe
nasal cavityby the placement of nasal packsintoeach
nostril at the end of the procedure.
L

. Whenamedianglossotomy has been performed, the in-
trinsicmusculatureand inferiorandsuperiorsurfacesof
thetongueare sutured separately as well as the floor of
themouth.
Graftsand Pharyngeal Mucosal Flaps
DermalFatGrafts
Freeskingraftsor dermal fat grafts are useful in closing de-
fectsintheregionofthe clivus.We prefer a dermal fat graft,
whichislaidoverthe dura after removal of the epidermis.3
Thegraftshouldbe of sufficient area to allow for shrinkage
orpartialresorption, but vascularization of the dermal fat
graftusuallyoccurs, and surrounding epithelial ingrowth
andgranulationtissue will contribute to closure of the de-
fect.Afatgraft by itself will usually resorb and may also be
pronetoinfectionby flora of the nasopharyngeal cavities.
FasciaLata Grafts
Thesegrafts may be used to repair larger dural defects. They
dependon underlying
tissue for vascularization
and nutri-
tionandare technically
more difficult
to fix in place. For
thisreasonthe survival of fascia lata grafts is not reliable.
Mucosal
Flaps
Forlargerduraldefects or when there has been previous ra-
diotherapy,
mucosalflaps have been developed. These have
theadvantageofproviding healthy vascularized tissue for
closureandhealing. Flaps are superior to grafts because
theyprovidebetter protection for vessels, bones, and carti-
lage:toleratefurther radiotherapy; resist infection; and are
lessproneto resorption or contraction. Radial forearm flaps
havebeenpreviously used in transoral-transmandibular
surgery,but such microvascular free-tissue transfers are
technicallymore demanding and increase the operating
timesignificantly.6We advocate the use of nasal septal and
lateralpharyngealmucosal flaps.
Nasal Septal
Duringthe initial exposure of the sphenoid rostrum, the
mucosaofthe nasal septum is separated laterally to either
sideofthe midline. Such dissection may be useful during
closurebecauserotational flaps can be created from the
mucosaof the posterior nasal septum to close a dural de-
fect.Thesubmucosalplane is dissected by making an inci-
sionwith a sharp knife, and developed by observing the
correctplane,distinguishable by the bluish hue of the un-
derlyingcartilage.The flap is developed with a blunt or
sharpelevatorunder direct vision and is turned posteriorly
tocoverthecIivaldural defect (Fig.8-3A).
Lateral Pharyngeal
Alternativelya rotational flap can be created from the pha-
ryngealmucosa,which is especially useful when there is a
largeduraldefect.Aflap of mucosa is made from the lateral
8
Transoral Closure
75
B
Figure 8-3
(A)The nasal septal mucosal flap and posterior reposi-
tioning duringthe closureofclivaldura. (8) Creationoflateralpharyn-
gealmucosalflapsforclosureofa clivalduraldefect.
pharyngeal wall, based superiorly or inferiorly, and turned
medially to the cIivaldefect. Forthis reason care is taken to
preserve as much mucosa as possible during the approach
(Fig.8-38).
Maxillotomy Reconstruction: Repair of the Roof
of the Oral Cavity
SoftandHardPalateRepair
The soft palate is closed in two layers (muscle and mucosa)
whereas the mucosa over the hard palate is a single layer
(Fig. 8-4). Imprecise approximation of the soft palate may
cause velopharyngeal dysfunction due to scarring of the
soft palate. In cases where the hard palate is split, reap-
proximation while maintaining vascularity is important,
especially in high-risk groups (chronic steroid therapy, dia-
betes,and after irradiation).Minordefectsofthe palateal-
most always heal with regular applications of Whitehead's
varnish.7
\

76
OccipitocervicalJunction:AnteriorApproach
Figure8-4
Operativephotograph showing the closure of the soft
palate.
Aspreviously described the divided hard palate and max-
illa are fixed together with preshaped
titanium plates
(Fig. 8-5). The nasal cavity is packed with ribbon-gauze
soaked in Whitehead's varnish to encourage healing of
the nasal mucosa and septum. Bypredrilling the holes for
the plates before maxillotomy it is easier to approximate
the maxilla and roof of the oral cavity precisely. This is nec-
essary to avoid malocclusion of the teeth. Oronasal fistulae
may occur, particularly at the junction of the hard and soft
palate and the vomer. Careshould be taken, therefore, while
closing the mucosa of the palate.
Figure 8-5
Final placement of the titanium
miniplates for the
anatomical alignment of the maxillary butresses.
Mandibulotomy Reconstruction: Repair of the Floor
of the Mouth
At the end of the procedure, the mandible and teeth are ap-
proximated. Sometimes one or both temporomandibular
joints have become dislocated.Thisshould be corrected while
repairing the mandible; otherwise a second anesthetic willbe
required later for reduction and relocationof the mandible.
In cases where a glossotomy has been performed, the
tongue is closed using 3-0 absorbable sutures, avoiding
dead space and hematoma formation. The intrinsic muscles
of the tongue are brought together with 2-0 polyglycolicin-
terrupted
sutures. The musculature
of the floor of the
mouth is sutured without excessive tension to prevent post-
operative scarring and swallowing difficulties. The mucosa
is closed with 3-0 or 4-0 absorbable sutures.
The two halves of the mandible are reconstructed using
the predrilled titanium miniplates and screws, avoiding
dental roots.8The soft tissues of the lip, chin, and submental
region are sutured in anatomical layers.
+. Outcome
Postoperative Management
1.
The patient is observed in the intensive care unit usu-
ally for 48 hours after the operation. Intermittent air
compression stockings (Flowtron boots, Huntley Health
Care, Luton,UK)are applied to the legs to assist venous
return. These are also used during the induction of gen-
eral anesthesia, which represents the period of greatest
risk for deep vein thrombosis. and throughout the oper-
ation. Arterial and central venous lines and a Foley
catheter remain in situ.
2.
Good airway management
is paramount.9 The tra-
cheostomy may be removed once pharyngeal edema
has subsided (usually 2-3 days after surgery) unless
there is dysfunction of the lower cranial nerves. With
extended approaches, a tracheostomy
and percuta-
neous endoscopic gastrostomy (PEG)tube may be re-
quired for a longer period. The nasotracheal tube may
be removed when the patient's respiratory function has
normalized. The elderly and patients with lower cranial
nerve palsies are at risk of airway compromise and
respiratory
infections. These patients
benefit from
frequent suctioning, postural drainage, and positive air-
ways pressure assistance.
3.
Nasalpacks may be removed after 2 to 3 days.
4.
The risk of infection is minimized by attention to hy-
giene and regular observation of the mouth and nose.
5.
Hydrocortisone ointment (1%)is applied every 8 hours
to the lips, gums, and buccal mucosa to reduce postop-
erative swelling.
6.
A lumbar CSFdrain is used for 5 days postoperatively
when the dura has been breached. With persistent CSF
leakage, the drain may remain in place for up to 7 to 10
days with antibiotic cover. Beyond this period a lum-
boperitoneal shunt is preferable.

7. Broad-spectrumantibiotics are administered
for the
first48 hours. If there are signs of meningitis the ap-
propriateantibiotics are given after CSFanalysis. In
casesofdural penetration and CSFleakage it is prefer-
ableto administer antibiotics that cross the blood-
brainbarrier.
8. Thepatient should not take any solids or fluids orally
for5daysafter the surgery. During this period nutrition
andmedicationscan be administered intravenously and
througha nasogastric tube.
9. AnH2 blocker or proton pump inhibitor is recom-
mended.Antiemetics should be administered
as re-
quiredto prevent regurgitation and soiling of the oral
cavity.
10.Painiscontrolledwith opioids as required. Surprisingly
thesepatients tend to require modest amounts of anal-
gesiaonly.
11.Aroutinecomputed tomographic (CT)scan is obtained
withinthe first 2 to 3 days to exclude the presence of
excessiveintracranialblood or air.
PostoperativeAssessment
of Bulbar Function and
OralCavityDysfunction
CranialNerveMorbidity
Transoralapproaches to lesions of the foramen magnum
anddivalregionmaydamage the facial (CNVII),glossopha-
ryngeal(CNIX),vagus (CN X), accessory
(CN XI), and hy-
poglossal(CNXII)nerves due to their proximity (Fig. 8-6).
It is important to assess
these
nerves
before
and after
surgery.l0
Isolatedcranial nerve deficits rarely produce significant
disabilitybut the presence of two or more deficits may im-
pairspeechand swallowing. Damage to the mandibular di-
visionof the facial nerve may cause poor lip sealing and
drooling,exacerbated by dysfunction of the oropharynx
thatmightaccompanymajor transoral surgery.
InjurytoCNIXor CNXcauses dysfunction of the larynx
andpharynx.Such patients
may have mild symptoms
(hoarseness,
poor cough, and dysphagia) or life-threaten-
ingproblems(airway compromise, stridor, or aspiration
pneumonia).Isolated glossopharyngeal
nerve injury is
rarelydetectable. Complete section of the vagus nerve
abovethe foramen magnum is the most common injury
afterresectionof tumors of the skull base. If this occurs
theipsilateralvocalcord remains in the intermediate posi-
tionbetweenfull abduction and adduction. Together with
anesthesia
of the supraglottic larynx, this produces a weak
and"breathy"voice. Ahigh vagal injury or damage to the
pharyngealplexus may also result in palatal paresis with
deviationof the uvula to the contralateral
side. This pro-
ducesanasaltone of voice and leads to nasal regurgitation
offluids.
TheCNXI hasspinal and cranial parts. In transoral opera-
tionstheaccessorynerve cannot be repaired at the time of
surgery.Injuryofthe spinal portion causes inability to turn
theheadtoward the side of the lesion and to shrug the
8
Transoral Closure
77
Figure 8-6
Operative photograph
showing the
proximity of
hypoglossal nerve rootlets to a dival intradural tumor. Extirpation
ofthis tumor maycause disturbances inthe postoperative function of
this nerve.
ipsilateralshoulder.ThecranialportionofCNXIisjoined by
the vagusnerveand contributesto dysphoniaand dyspha-
gia when damaged.
Unilateral hypoglossal nerve injury may not be disabling
(despite deviation of the tongue toward the side of the le-
sion and atrophy of the ipsilateral half), but bilateral paraly-
sis has profound effects on swallowing and speech.
Assessment
and Management
of Oral Cavity Dysfunction
Transoral surgery may be associated with an increased risk
of velopharyngeal dysfunction (VPD),which manifests as
difficulties in speech and swallowing. Although VPDis ex-
acerbated by lower cranial nerve deficits, the main cause is
the creation of a large dead space where the lesion was
originally, and scarring of the pharynx and soft palate. This
risk can be minimized by good surgical technique (de-
scribed earlier in this chapter) and, although it can be a dif-
ficult problem in a few patients, there may be no suitable
alternative to a transoral route.1I
Fiberoptic laryngoscopy, nasal endoscopy, and fluoro-
scopic barium swallow studies are useful to determine the
function of the vocal cords and the patient's ability to swal-
low. Laryngeal electromyography may be useful in predict-
ing the prognosis after CNXinjury.
In terms of management,
instructions
in swallowing
techniques and rehabilitation are given by a speech and

78
OccipitocervicalJunction:AnteriorApproach
....
language therapist,12-14Lipclosure may be improved by a
dynamic suspension procedure (temporalis muscle transpo-
sition) or a Z-plasty,when reinnervation of the mandibular
branch of the facial nerve is not anticipated. Injection of
Gelfoam into the vocal cords may improve tension and
therefore function of the cords. Ifrecovery is not expected, a
References
1.
Crockard
HA. Bradford
R. Transoral
transclival
removal
of a schwan-
noma anterior
to the craniocervical
junction:
case report. J Neurosurg
1985;62:293-295
2.
Hadley MN. Martin
NA. Spetzler
RF.Sonntag
VKH. Johnson
Pc. Com-
parative
transoral
dural closure
techniques:
a canine
model.
Neuro-
surgery
1988;22:392-397
3.
Crockard
A, Macaulay
E. Plowman
PN. Stereotactic
radiosurgery.
VI:
Posterior
displacement
ofthe
brainstem
facilitates
safer high dose ra-
diosurgery
for clival chordoma.
BrJ Neurosurg
1999;13:65-70
4.
Crockard
HA. Anterior
approaches
to lesions
of the upper
cervical
spine. Clin Neurosurg
1988;34:389-416
5.
Yang S. Gao Y.Clinical results
of the transoral
operation
for lesions of
the
craniovertebral
junction
and
its
abnormalities.
Surg
Neurol
1999;51: 16-20
6.
Schwartz
MS. Cohen JI. Meltzer T, et al. Use of the radial forearm
mi-
crovascular
free-flap graft for cranial base reconstruction.
J Neurosurg
1999;90:651-655
7.
Harkey HL. Crockard
HA. Transoral-extended
maxillotomy.
In: Dick-
man CA.Spetzler
RF.Sonntag
VH. eds. Surgery ofthe
Craniovertebral
Junction. New York: Thieme;
1998:371-381
8.
Delgado TE. Garrido
E. Harwick
RD. Labiomandibular.
transoral
ap-
proach to chordomas
in the clivus and upper
cervical
spine. Neuro-
surgery 1981 ;8:675-683
paralyzed vocal cord may be permanently displaced medi-
ally. Ifthere is significant permanent injury of the pharyn-
geal plexus of CNXor formation of an oronasal fistula caus-
ing nasal regurgitation. then oronasal separation may be
achieved by using a palatal prosthesis or various pharyngeal
flaps.IS
9. Howard RS. Henderson
F. Hirsch NP. Stevens JM. Kendall BE.Crockard
HA. Respiratory
abnormalities
due to craniovertebral
junction
com-
pression
in rheumatoid
disease. Ann Rheum Dis 1994;53:134-136
10. Menezes
AH. Complications
of surgery
at the craniovertebral
junc-
tion:
avoidance
and
management.
Pediatr
Neurosurg
1991-
92;17:254-266
11. Tuite GF, Veres R, Crockard
HA. Pediatric
transoral
surgery:
indica-
tions. complications.
and long-term
outcome.J
Neurosurg
1996;84:
573-583
12. March JL. O'Daniel TG. Management
of velopharyngeal
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a
surgeon's viewpoit. Probl Plast Reconstr Surg 1992;2:73-85[p1 ][p21
13. Hirano M. Nozoe I. Shin T. Maeyama
1. Electromyography
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In: Hirano M. Kirchner JA. Bless DM. eds. Neurolaryn-
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HM. Rehabilitation
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vocal
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paralysis
and/or
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Laryngoscope
1997;107:1322-1331

9
ExtendedMaxillotomy Approach
forHighClinical Pathology
RajP.TerKondandLawrenceJ.Marentette
. Indications
. Contra
indications
. Advantages
. Disadvantages
. Objective
. Preoperative
Planning
Theextendedmaxillotomy
approach
to the skull base pro-
videsunparalleledexposure of the midline craniovertebral
junctionviaan anterior approach. This approach provides
theneurosurgeonaccess from the superior clivus to the
bodyofthethird cervicalvertebra (C3).Removalof the bony
nasalseptumextends the access superiorly to the sphenoid
sinus.Routinetransoralapproacheswith palatalretraction
onlyprovideaccessto the inferior clivus to the superior
bodyofC3(Fig. 9-1). When compared with the transoral
approach,
theextendedmaxillotomy approach is technically
moredifficult,extends the operative time by approximately
6hours,andhasgreater potential morbidity. It is critical that
thesurgeonsidentifythe exact extent of the lesion preoper-
ativelytodeterminethe appropriate approach.
Theprocedureconsists of a horizontal osteotomy of the
maxilla(LeFort I),splitting the hard and soft palate, and
verticalpharyngotomy.The term extended maxillotomy is
confusingbecause there are at least three different ap-
proachesto the skull base with the same name.1-3 The
techniquedetailed in this and the next chapter was first
describedby James and Crockard.2 This procedure
is
basedonmaxillofacial techniques and is more appropri-
atelytermed"two-piece LeFort I osteotomy with palatal
split."4The single-piece
Le Fort I osteotomy
without
palatalsplit (Crawford's "unextended"
transmaxillary
.
SurgicalTechniques
Tracheostomy
Patient Positioning
Exposure
of Maxilla and Nasal Cavity
Preparation
for Le Fort IOsteotomy
Palatal Split
Le Fort IOsteotomy
Vertical
Pharyngotomy
.Conclusion
approach) only allows access to the clivus and not the
cervical spine.s
.
Indications
.
Congenitalcraniovertebraljunction abnormalitieswith
basilarinvagination(e.g.,osteogenesisimperfecta)
.
Rheumatoidarthritis withodontoiddisplacement
.
Fracturedislocationofthe odontoidprocess
. Midline,extraduraltumorsoftheclivus and upper cer-
vicalspine
. Basilaraneurysms
.
Contraindications
.
Intradural tumors
.
Extradural tumors with lateral extension
.
Acute sinusitis
.
Severe trismus
.
Poor dentition
79