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

49
Tumors ofthe Thoracolumbar Spine
387
Stage 1
Stage 2
lesions,in which the tumor is confined to the vertebral
compartment and type Blesions, where the tumor extends
beyondthe bony limits. Stage Ilesions are low-grade malig-
nanttumors surrounded by a thick pseudocapsule, which
containsmicroscopic islands of tumor (Fig. 49-3). A cap-
sule,if present, is thin and incomplete. Stage lAlesions are
Stage IA
Stage IIA
Figure 49-2
The three stages of benign
tumors. Stage 1: asymptomatic and inactive
tumors surrounded byatrue capsule.Stage 2:
symptomatic, actively growing tumors sur-
rounded byathick capsuleencasedinpseudo-
capsuleofreactivetissue.
confined to the bone. whereas
stage IB lesions extend
outside this compartment. Stage IItumors are high-grade
malignant lesions. They are rapidly growing lesions that do
not allow sufficient time for the formation of a reactivetis-
sue pseudocapsule.
There is continuous
seeding with
satellite nodules and skip metastases are also identified.
Stage IB
Stage liB
Figure
49-3
Malignant
spinal tu-
mors.
Stage I lesions are low-grade
malignant tumors. Stage IA:the tumor
is confined to the vertebral compart-
ment. Stage IB:the tumor extends be-
yond the bony limits. Stage IIlesions
are
high-grade
malignant
tumors.
Stage IIA:lesions are confined to the
bone. Stage liB:lesions extend outside
the bone. Stage IIIlesions are charac-
terized
by their metastatic
abilities.
Stage iliA:lesions are confined to the
bone. Stage IIIB:lesions extend
out-
side the bone.

388
Thoracicand Thoracolumbar Spine: Pathology of the Thoracic and Thoracolumbar Spine
Pathological fractures are common and invasion of the
epidural space occurs. Stage IIAlesions are confined to the
bone, whereas stage liB lesions extend outside this com-
partment. StageIIItumors are characterized by metastasis,
either regionally in the lymph nodes or more distantly to
other organs. Onceagain, the bony lesion may be confined
to the vertebra (stage iliA),or may extend beyond this com-
partment (stage IIIB)(Table49-6).
. Treatment
Acomprehensive review of the treatment of spinal tumors
is well beyond the scope of this chapter. An overview is
therefore presented following here. The fundamental prin-
ciples guiding the surgical management of spinal tumors
are based on the surgical staging systems discussed earlier.
Asymptomatic benign tumors of the spine usually do not
require treatment. They often regress spontaneously and
can therefore be followed clinically. Symptomatic tumors
should be treated surgically. Stage 2 disease requires in-
tralesional curettage or en bloc excision, whereas stage 3
disease requires wide excision. The risk of recurrence for
stage 2 and 3 tumors is not negligible and adjuvant therapy
may be required if the surgical resection is inadequate. In
those instances where there is encroachment
on neural
structures, a wide excision may not be feasible and a more
limited resection should be undertaken and followed with
adjuvant therapy.
Malignant spinal tumors are generally managed opera-
tively.Surgeryis indicated for those tumors that are23:
1.
radioresistant
2.
causing compression of the neural structures with en-
suing neurological deficits
3.
producing instability of the spine
4.
causingintractable pain
Thepurpose of surgery is to decompress the neural struc-
tures, realignthe spine, and restore stability. Although wide
resection ofthe tumor is desired, this frequently is not pos-
sible. Under these circumstances, surgery is palliative and
adjuvant therapy plays an important role in the treatment
of local disease and in the prevention
of recurrence.
Metastatic spinaldisease can also be managed surgically.
The indications for surgery are similar to those for malig-
nant disease and include23:
1.
the need for tissue diagnosis
2.
the presence ofa radioresistant tumor
3.
intractable pain that does not respond to nonoperative
measures
4.
progressive neurological deterioration accompanying
nonoperative treatment
5.
neural compression
with neurological compromise
6.
spinal instability
The purpose of surgery, as described for malignant tumors,
is the decompression
of the neural structures, followedby
the realignment
and fusion of the spine. Adjuvant therapyis
required for control of local disease.
The surgical procedures
performed
for the treatmentof
spinal tumors are selected
on the basis of the WBBstaging
system (Fig. 49-4).
Anterior, posterior, or combinationap-
proaches are used. Vertebrectomies
or hemivertebrectomies
are performed
through
an anterior
approach. Avertebrec-
tomy is indicated
if the lesion is confined to WBBzones4to
8 or 5 to 9. When the tumor occupies WBB zones 3 to5or8
to 10,a hemivertebrectomy is advocated. Finally,forposte-
riorly located lesions (WBB zones 10 to 3), a wide laminec-
tomy is indicated.
Nonoperative
adjuvant
therapy consists of radiationther-
apy, chemotherapy,
and hormonal
therapy. Radiotherapyis
a well-recognized
tool in the management
of spinal lesions.
Nevertheless,
the indications
for radiation
therapy asthe
primary
treatment
for this disease
remain somewhat con-
troversial.
It is reasonable
to consider
radiotherapy inthose
patients with23:
1.
radiosensitive
tumors
2.
axial pain in the absence of neurological deficit
3.
stable neurological
deficits due to soft tissue compres-
sion
4.
widespread
metastatic
disease
5.
limited life expectancy
6.
medical conditions that preclude surgery
The response
rates will vary according
to the radiosensi-
tivity
of the tumor
in question.
In general,
prostate and
Iymphoreticular
tumors
are
radiosensitive.
Metastatic
breast
and lung disease
demonstrate
moderate
responses
to radiation,
whereas
gastrointestinal
and renal tumorsare
radioresistant.
Patients
with radioresistant
or moderately
sensitive
spinal metastases
may be considered
for denovo
surgical
management,
followed
by radiotherapy.
Several
other
issues
arise
regarding
the
use of radiation in the
spine. These include dosage, spinal cord tolerance, ensuing
spinal
instability,
and
late
complications
relating to
radiation.
Chemotherapy,
hormonal
therapy,
steroid
therapy, em-
bolization, and bracing all playa role in the overall manage-
ment of patients with tumors of the spine. Chemotherapyis
primarily indicated
for the treatment
of the primary disease
and is less useful for the neurological
symptoms
associated
with spinal lesions. Hormonal manipulation
is appropriate
for hormone-dependent tumors. Steroids are most usefulin
the acute phase of spinal cord compression
and neurologi-
cal deficit as a prelude to surgical (or occasionally radiation)
therapy.

12
49
Tumorsof the ThoracolumbarSpine
389
12
12
Theoverall5-year survival rate for patients with benign
spinaltumors has been reported to be 86%.24Prognosis for
malignantdisease of the spine is not as good. Boriani and
Weinsteinreport that patients who had a complete exci-
sionoftheir malignant lesion at initial surgery had a 5-year
survivalrate of 75%.3However, if the operative procedure
waslimited to biopsy or incomplete resection, survival
ratesat 5 years were 18 and 33%, respectively. Unfortu-
nately,complete resection of malignant lesions is often not
possible.Overall, more aggressive tumors will have a
poorerprognosis. Patients with solitary plasmacytomas
(whichare the only malignant lesions with a > 50%5-year
survivalrate3) do better than those with lymphoma or
osteosarcoma.
Froma neurological standpoint, patients who progress
fromtheearliestonset of symptomsto a major deficit in
. Prognosis
Figure 49-4
Surgical treatment of spine tumors is
based on the WBBstaging system. The figures on the
left depict the WBBzones that are used to characterize
the location of the lesion. The figures on the right de-
pict a schematic representation used for the treatment
ofthe correspondinglesion.
less than 24 hours have a very poor prognosis for recovery,
regardless of treatment. Patients who present with para-
paresis have a low chance of regaining the ability to ambu-
late, whereas patients who are ambulatory at the time ofdi-
agnosis generally remain so following successful treatment.
.
DifferentialDiagnosis
Benign Tumors
Osteochondroma
This is the most common benign skeletal tumor. The lesion,
also known as an exostosis, progresses very slowly and gen-
erally remains asymptomatic. Asa result, the incidence of
osteochondromas
is likely underreported.
Neurological
compromise is rare and occurs in less than 1%of cases.2S

......
I
390
Thoracic and Thoracolumbar
Spine: Pathology of the Thoracic and Thoracolumbar
Spine
Fifty percent of those patients who do develop symptoms
are less than 20 years 01d.25Symptoms occurring in adult-
hood are the result of degenerative processes that lead to
canal narrowing.26Osteochondromas are more common in
males. They may arise from any portion of the vertebra and
usually cease to grow at skeletal maturity. Ifthe osteochon-
droma is noted to be increasing in size, degeneration to
chondrosarcoma should be suspected. Plain radiography
may be helpful but is usually not diagnostic for osteochon-
droma. cr and MRIare therefore the studies of choice. MRI
is particularly useful in defining the extent of the cartilagi-
nous cap, which is an important structure requiring resec-
tion at surgery. Surgical treatment
is recommended for
lesions that are either symptomatic or continue to grow
past skeletal maturity. Complete removal is usually possi-
ble. As previously indicated, the cartilaginous cap must be
completely resected to prevent recurrence. Ifsurgery is per-
formed for neurological symptoms, improvement is noted
in 90%of patients postoperatively and is dependent on the
extent of cord manipulation.27
Osteoid Osteoma
and Osteoblastoma
These tumors account for 10%of primary spine tumors and
occur in the second and third decades of life.28These os-
teoblastic lesions are differentiated by size. Osteoid osteo-
mas are less than 2.0 cm in diameter-any lesion larger than
this is defined as an osteoblastoma. The tumors are most
commonly found in the lumbar spine. Typically,the poste-
rior elements (pedicles) are affected. Backpain and painful
scoliosis are common presenting signs. Aspirin classically
provides dramatic pain relief. Radicularpain resulting from
nerve root compression has also been described.29On occa-
sion, stage IIIosteoblastomas cause cord compression.
Radiographically,these lesions are destructive and expan-
sileo The tumors
are lobulated
and
the surrounding
bone has scalloped geographic margins.3DArim of reactive
bone usually surrounds osteoblastomas, which on MRI
can be mistakenly interpreted as soft tissue extension. Bone
scan remains the most sensitive means for diagnosing these
tumors.
Osteoid osteomas are treated with intralesional total ex-
cision. Osteoblastomas, due to their aggressive nature, re-
quire wide excision.The prompt relief of pain after surgery
is the best indicator of complete removal of tumor. Scoliosis
also improves after surgery.The use of radiotherapy is con-
troversial but it may be required in those cases where com-
plete excision is not possible, or in those patients with an
advanced stage osteoblastoma.3.6
Aneurysmal
Bone Cyst
This lesion is commonly found in the thoracolumbar spine
in patients less than 20 years of age.The posterior elements
are more commonly involved.Aneurysmal bone cysts typi-
cally present with back pain (95%).2Spinal cord compres-
sion, pathological fractures of the spine, spinal rigidity, and
scoliosis may also be noted.
X-rays show an expansile osteoclastic cavity containing
strands of bone. Athin rim of reactive cortex is often seen
but may be absent in as many as 30%of cases.31A unique
feature of these lesions is that adjacent vertebrae maybe
involved. MRImay reveal septations and fluid levelswithin
the lesion, whose signal characteristics
are consistent with
blood products. Finally,angiography may show largeblood-
filled spaces.
Tumor resection is generally curative. Embolizationand
low-dose
radiation
therapy
have been used preoperatively
to control bleeding. These modalities may also be helpful as
stand-alone measures in the treatment of aneurysmalbone
cysts.
Hemangioma
These
tumors
are rarely
symptomatic
and yet are quite
prevalent
in the general population
(10%). Lesions areusu-
ally solitary and are found in the anterior vertebralbodies.
They may become
symptomatic
either
during pregnancy,
where they present as pathological fractures, hematomas,
expanding soft tissue tumors, or ballooning ofthe vertebral
body, or in the third or fourth decades of life.16-18
X-rays show the classic thickening of the trabeculae,
manifested as vertical striations within the vertebralbody.
There may be expansion
and erosion of the body. Asofttis-
sue mass may also be identified.
On cr axial images,the
thickened trabeculae appear as polka dots. MRIshowsmot-
tled lesions with high signal on both 11- and T2-weighted
images. Angiography, which is recommended in thesepa-
tients preoperatively, demonstrates pooling ofcontrastma-
terial within the lesion.
Hemangiomas may be treated with radiation, surgery,or
embolization.
Radiotherapy,
administered
as a single
course, is indicated for the relief of back pain.3Surgeryis
advocated for lesions that cause pathological fracturesand
neurological
deficit. Embolization
may be useful in relieving
symptoms
but is more commonly
used preoperatively to
obliterate
the major feeding vessels to the tumor.
Giant Cell Tumor
These lesions are the most common benign tumorsof the
sacrum.
They are more common
in females and generally
occur in the third and fourth decades of life.35These tumors
most commonly present with local pain. Unfortunately.
neurological deficits are frequently encountered and symp-
toms may be present for several months before the diagno-
sis is made. Giant cell tumors may cause spinal cordor
nerve root compression.
X-rays and cr scans show a lytic septated lesionwithiq
the vertebral
body that is surrounded
by marginal sclero-
sis. There may be cortical
breakthrough
and a soft tissue
mass.
Treatment consists of tumor resection with widemar-
gins. This is usually curative,
but in cases of recurrentor
invasive disease, en bloc resection may be required.Preop-
erative embolization is usually helpful. Adjunctiveradio-
therapy may be necessary but unfortunately mayleadto
malignant sarcomatous degeneration. Cryosurgicaltech-
niques have also been recommended to increase the intra-
operative margins.36
..

EosinophilicGranuloma
49
Tumorsof the ThoracolumbarSpine
391
Thisbenignlesionbelongsto a spectrumofdiseases,rang-
ingfroma localized and self-limiting process (histiocytosis
X) to the multisystemic
conditions
known as Hand-
Schuller-Christiandisease and Letterer-Siwe disease. It is
usuallyseen in children less than 10 years of age and most
commonlyaffects the vertebral body in the thoracic spine.
Theclinicalmanifestations are nonspecific and include sys-
temicsymptoms (fever,weight loss), pain, rigidity, and neu-
rologicaldeficits.37
Radiographically,a central area of lysis within the verte-
bralbodyis seen, associated with a marked periosteal reac-
tion.Themargins of the lesion are poorly defined. Cavita-
tionand collapse of the vertebra may occur, such that a
flatteneddisk of dense cortical bone is seen between two
intact intervertebral disks. This appearance is classic of
eosinophilicgranuloma and is known as vertebra plana. On
MRI,the signal is variable on T1-weighted images, with
markedenhancementfollowingthe administrationofcon-
trast.The lesion is hyperintense on T2-weighted images
("flare"reaction), suggesting erroneously, the presence of
anaggressiveprocess.38On bone scan, the images are cold.
Treatmentof eosinophilic granuloma is usually nonoper-
ative.Ingeneral, there is spontaneous regression of the dis-
ease.Surgical therapy is, however, indicated in cases of
spinalinstabilityor neurologicalcompromise.It may also
benecessaryin cases of extensive disease where pathologi-
calfractures are likely. In these instances, curettage and
bone grafting are appropriate. Overall,the prognosis for pa-
tients with eosinophilic granuloma is good. Recurrence is
uncommon and recovery of neurological function is usually
excellent3(Table49-7).
Malignant Tumors
Multiple Myeloma and Plasmacytoma
These disorders are neoplastic Iymphoproliferativediseases
involving plasma cells. They likely represent a spectrum of
diseaseand arethe mostcommontypeof primarytumorto
affect the spine. Plasmacytomas tend to be the less aggres-
sive lesions, found predominantly in the thoracic spine.
They are solitary tumors typically found in men over the
ageof 50.Onaverage,symptomsare presentfor 6months
before a diagnosis is made. Pain is the most common com-
plaint but spinal cord compression and radiculopathy are
also frequent, occurring in as many as 50%of cases.Progno-
sis is good,with a 5-year disease-free survival of60%.39
Multiple myeloma is far more aggressive. The spine is in-
volved at multiple levels. Other hematopoietically active
bones are also affected. Clinical manifestations reflect the
extent of the disease. Systemically, renal failure and recur-
rent bacterial infections are the most frequently encoun-
tered problems. Anemia, coagulopathy, neutropenia, and
hyperviscosity are also common. Spinal involvement results
in failure of the vertebral body and consequently deformity,
instability, and neurological compromise. The disease is
Table49-7
Common
Benign
Spinal
Tumors
Region of
Lesion
the Spine
Spinal Component
Age (yr)
Plain X-ray
CT
MRI
Osteochon-
C spine (C2) Transverse or
<20
Pedunculated
mass
Cortex of bone and
Mixed signal on Tl- and
drama
spinous process
tumor
blend
T2-weighted
image
Cartilaginous
cap
has calcified foci
Osteoma
L spine
Neural arch
10-20
Variable, may be
Dense sclerosis
Low signal on Tl- and
radiodense with a
surrounding
a lytic
T2-weighted
image
sclerotic rim
lesion
Osteoblastoma
Lspine
Neural arch
< 30
Well-defined,
Same as x-ray; a
Intermediate
signal on
Often multifocal
10buiated,Iytic
sclerotic rim, soft tissue
Tl- and mixed high
expansile mass
extension
is common
signal on T2-weighted
image
Aneurysmal
TL spine
Posterior Elements
<20
Expansile osteoclastic
Same as x-ray and a
Multiple
fluid levels
bone cyst
cavity with bony
reactive rim and
with evidence of
strands
thin cortex
blood products
Hemangioma
T spine
Vertebral
bodies and
30-40
Striated vertebral
Polka dots
Mottled
lesions with
posterior
elements
body
high signal on Tl- and
T2-weighted
image
Giantcell tumor
TL spine
Vertebral
bodies
30-40
Geographic,
lytic,
Same as x-ray, possible
septated appearance
soft tissue mass and
with marginal sclerosis
cortical
breakthrough
Eosinophilic
TL spine
Vertebral
bodies
< 10
Cavitation,
collapse,
Same as x-ray and
Flare reaction
granduloma
and vertebra plana
central lytic area,
around the lesion
poorly defined margins,
marked periosteal
reaction

392
Thoracic and Thoracolumbar Spine: Pathology of the Thoracic and Thoracolumbar
Spine
unfortunately rapidly progressive, with life expectancy esti-
mated at 2 to 3 years from the time of diagnosis.
On plain x-ray or CT,multiple myeloma is characterized
by lyticdestruction of bone. This is mainly seen in the pedi-
des or anterior column and is associated with vertebral col-
lapse or vertebral plana.16MRIis the imaging test of choice
because it reveals the extent of bony involvement and
demonstrates extension into the paraspinal soft tissue.4o
Bonescans are generally not helpful because the absence of
osteoblastic activity yields a negative study. Other useful
tests include serum and urine electrophoresis. Monoclonal
immunoglobulins are identified in 98% of patients with
multiple myeloma41and in 30%of people with solitary plas-
macytoma.42Because these tumors are quite radiosensitive,
conventional radiotherapy is the mainstay of therapy. Al-
though surgical intervention has little effect on the progno-
sis,surgery is indicated in those patients presenting acutely
with neurological compromise or spinal instability.43In ad-
dition, isolated disease that has not responded to maximal
radiation can be managed operatively. In general an anterior
approach is required to successfully decompress the neural
structures. The reconstruction is influenced by the extent of
the disease. Bonegraft or methyl methacrylate can be used.
These are enhanced with instrumentation, which is usually
required both anteriorly and posteriorly to achieve ade-
quate internal stability. Postoperatively, radiation therapy is
administered.
Thereafter,
serum
protein
immunoelec-
trophoresis is performed to monitor treatment response.
It is also a reliable indicator of dissemination of disease
and, in the event of recurrence or spread, chemotherapy is
administered.
PrimaryOsteosarcoma
Osteosarcomas are the second most common malignant
primary bone neoplasm. They are bone-forming tumors
that occuras primary lesions, metastatic lesions, or lesions
secondary to radiation to the spine, Paget's disease, or fi-
brous dysplasia. In younger age groups, osteosarcoma is
mainly found in the long bones. In older patients, the spine
is principallyaffected. The anterior elements are most com-
monly involved, although the pedicles and posterior ele-
ments may also be infiltrated. Bonydestruction may result
in vertebral collapse, leading to pain and neurological
deficits. Cordcompressionis a common finding.
Radiographically,both osteoblastic and osteolytic lesions
are seen. These tumors are well seen by CT,although MRI
provides better definition of the soft tissue extension. Bone
scans are necessary to assess the possibility of multifocal
disease, and CTscans of the chest are important to identify
lung lesions.
Ideally,aggressive surgicalresection is desired. This is fre-
quently difficult in the spine, where more limited dissection
is realized. Unfortunately, subtotal resections are associated
with recurrence and poor prognosis. Indeed, osteosarcoma
of the spine carries a poor prognosis, with a median sur-
vival of 10 months.44 Chemotherapy may be administered
preoperatively to reduce tumor size, so as to increase the
chances of achieving negative margins. Postoperatively, ad-
juvant chemotherapy and radiation therapy have been used.
Ewing's Sarcoma
This is a rare malignant tumor occurring in the firstthree
decades
of Iife.3 In the spine,
it is usually found in the
sacrum. The tumor frequently
presents
with pain and neu-
rological compromise.
Patients may also detect a massand
complain
of fevers. Radiographically,
the tumor appearsas
lytic lesions in the vertebral
body, associated with periph-
eral sclerosis. Vertebral collapse and vertebra plana mayoc-
cur, producing
an appearance
that is difficult to distinguish
from eosinophilic
granuloma.
MRI is useful in definingthe
soft tissue component
of this disease.
Treatmenent
involves
en bloc resection
of tumor, fol-
lowed by chemotherapy
and radiotherapy.
Prognosis how-
ever is not good, with 5-year survival estimated at 20%.24
Chordoma
These rare, slow-growing, low-grade malignant tumors
arise
from
remnants
of the
notochord.
They are found
throughout
the spine, but most commonly
in the sacrococ-
cygeal region (50%) and the clivus (30%).45These tumorsare
more frequently
seen in males and typically present inthe
fifth to seventh
decades
of life. Clinical manifestations are
generally mild and slowly progressive, leading to longinter-
vals between onset of symptoms and diagnosis.Themost
common
symptom
is pain. Clivallesions
may be associated
with
signs
of increased
intracranial
pressure,
such as
headache,
visual disturbances,
dysphagia,
and cranial nerve
abnormalities. In the cervical and thoracic region,lesions
may result in myelopathy, either as a result ofdirecttumor
compression upon the spinal cord or secondary tovertebral
collapse.Inthe thoracolumbarspine,chordomasmayresult
in spinal stenosis and cause symptoms consistent withneu-
rogenic claudication. Radiculopathy as well as boweland
bladder dysfunction may also occur.
Radiographically,chordomas appear as lyticlesionsinthe
vertebral body associated with variable amounts ofcalcifi-
cation and minimal periosteal reaction. Asoft tissuemassis
frequently present and may be quite large. CT scanishelp-
ful in demonstrating the destructive process, whereasMRI
is the test of choicefordelineatingthe soft tissuecompo-
nent of this tumor. On T1-weighted images, chordomasare
inhomogeneous with predominantly low-signal intensity.
On proton density and T2-weighted images, the tumorhas
increased signal intensity. Radionuclide studies aregener-
ally not useful because the bone scan is often negativedue
to the minimal periosteal reaction. Once the tumor has
reached a large size, it may metastasize to lymph nodes,
lungs, liver,brain, bone, skin, or the heart. Therefore,anap-
propriate metastatic workup is required.
Treatment consists of surgery. Cure may be achievable
with en bloc wide-margin resection. Unfortunately, thisis
not alwayspossibleandthereforeaggressivetumordebulk-
ing is attempted and followed by radiotherapy.22High-dose
radiotherapy on its own helps to slow tumor progression
but does not eradicate the disease. It is therefore best used
as an adjunct to surgery. Biopsy, although occasionally
helpful, should not be performed until all the appropriate
staging studies have been evaluated. At the time ofdefini-
tive surgery, the biopsy track must be excised to prevent

49
Tumorsof the ThoracolumbarSpine
393
contamination. Indeed, incomplete excision of the biopsy
trackor the tumor itself is predictive of recurrence, which is
inturn related to prognosis.
Chondrosarcoma
Chondrosarcomasare slow-growing, hyaline cartilage-forming
tumors. Fewer than 10%ofthese
tumors
arise in the spinal
column.They are more frequently seen in males and usually
present in the fifth and sixth decades
of life. Patients
typi-
callypresent with pain, which is slowly progressive and fre-
quently worse at night. In addition, symptoms
of nerve root
and spinal cord compression
occur commonly.
The radiographic
appearance
of chondrosarcoma
is re-
lated to the grade of the lesion. Low-grade
tumors
cause
scalloping of the vertebral
cortex
and cortical
expansion.
High-grade lesions are characterized
by regions of bone de-
struction associated
with
sclerotic
margins
and variable
matrix calcifications.
Adjacent
levels may be involved and
softtissue masses are frequently
present.
CTscan is useful
indemonstrating
the extent of bony involvement
whereas
MRIdefines the soft tissue component.
Bone scan is helpful
inidentifying multi focal and metastatic
disease.
Surgery is the mainstay
of therapy. Because these tumors
are resistant to radiation
and chemotherapy,
wide surgical
excisionwith tumor-free
margins
offers the best hope for
cure.In the event of subtotal
resection,
cryosurgery
may be
helpfulto prevent local recurrence.46 Prognosis for patients
with chondrosarcoma
is most dependent
on the histologic
grade of the lesion. This parameter,
as well as the degree
of tumor resection,
is important
in determining
tumor
recurrence.
Lymphoma
Lymphomaof the spine occurs infrequently and, when pre-
sent,the tumor is of the non-Hodgkin's variety. These le-
sionsusually affect the anterior aspect of the spine in the
fourthto sixth decades. Spinal involvement may occur as a
manifestationof systemic disease or present as an isolated
bonytumor. The most common symptoms are back pain
andneurological deficits secondary to spinal cord or nerve
rootcompression. Myelopathy and radiculopathy occur in 2
to6%ofpatients with lymphoma and are usually related to
epiduraltumor rather than vertebral collapse.47
Lymphomasare sensitive to chemotherapy and radiother-
apy.Thesemodalities are therefore central to the treatment
ofspinallesions. Surgery is indicated in those patients pre-
sentingacutely with neurological compromise or spinal in-
stability.Ingeneral, anterior decompression will be neces-
sary,followed by fusion and instrumentation.
Ifthe tumor
marginsare positive, then both radiation and chemotherapy
arerecommended. Otherwise, postoperative chemotherapy
aloneisappropriate.
Paraspinal
SoftTissueSarcoma
Theseare rare tumors that arise from the paraspinous
muscles.Such tumors include liposarcoma, malignant fi-
broushistiocytoma, leiomyosarcoma, chondrosarcoma of
soft tissues, synovial sarcoma, angiosarcoma, and neurofi-
brosarcoma.48The neoplasm gradually increases in size and
may eventually encroach on the spine, the intercostal
nerves, the spinal canal, and the exiting nerve root. Symp-
toms reflect this pattern of growth. Imaging with CTand
MRIis helpful in establishing a diagnosis and provides use-
ful information for planning treatment. These same studies
are important to evaluate patient response to therapy and
to assess tumor recurrence.
Ideally, treatment consists of complete tumor resection.
This may be quite difficult, particularly if the lesion extends
into the spinal canal because the dura is frequentlyinvolved.
Forvery large masses, preoperative chemotherapy may help
reduce the tumor to a more manageable size. Postopera-
tively, chemotherapy and radiation are recommended to
augment the chances of favorable outcome. Prognosis for
paraspinal soft tissue sarcomas, however, remains worse
than for identical lesions arising in the extremities, likely
due to the difficulty in obtaining a gross total resection.
Metastatic Tumors
Metastases are the most common type of tumor affecting
bone.49Indeed, 50 to 85%of cancer patients will have skele-
tal metastases, the majority of whom will have involvement
of the spine. There is a predilection for the thoracolumbar
spine.50Metastases usually affect patients in the fourth to
sixth decades of life.They tend to arise in the lung, breast,
prostate, kidneys, thyroid, and gastrointestinal system and
spread to the spine by hematogenous routes or by direct ex-
tension. Aswith other lesions of the spine, these tumors can
cause pain, cord compression, and neurological deficits. The
main cause of pain and paralysis is pathological vertebral
body collapse by an osteolytic lesion.
MRIis the imaging test of choice. It is very helpful in the
evaluation of the spine for metastases and is probably more
sensitive than bone scanning.51CTscan provides informa-
tion about the extent of bony involvement and can be used
for guiding posterolateral
percutaneous
trans pedicular
biopsies.
Surgicaltreatment is often palliative. It is indicated forin-
tractable pain, acute neurological deficit, spinal instability,
or impending vertebral collapse. Radioresistant tumors can
also be treated surgically. However, one must consider life
expectancy as an important parameter when arrivingat the
decision to operate on patients with metastatic spine dis-
ease. Ifsurgery is necessary, preoperative embolization may
be required to minimize blood loss.
Radiotherapy has long been considered the treatment of
choice for spinal metastases, particularly if symptoms are
limited to pain. The outcome following radiation for pa-
tients with neurological deficit depends on the pretreat-
ment level of function. Eighty percent of patients either re-
main stable or improve neurologically following radiation.
Response to treatment also depends on the radiosensitivity
of the lesion. Prostate, breast, and Iymphoreticular system
metastases are generally radiosensitive, whereas renal and
gastrointestinal lesions are usually radioresistant. Overall,
prognosis
is most closely related
to early diagnosis.
The mean survival time is 7 months and only one third of
patients will liveto 1 year (Table49-8).

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Thoracic
and Thoracolumbar
Spine: Pathology
of the Thoracic
and Thoracolumbar
Spine
Table 49-8
Common
Malignant
Spinal Tumors
Region
Lesion
of the Spine
Spinal Component
Age (yr)
Plain X-ray
CT
MRI
Multiple myeloma
T spine
Pedicles and
> 50
Lytic lesions and
Same as x-ray
May show benign
and plasmacytoma
vertebral
bodies
vertebral
collapse
osteoporotic fracture
appearance
Osteosarcoma
CTLS spine
Vertebral
body
<30
Mixed osteoblastic
and
Same asplain x-ray
Mixed osteolysis
osteolytic
activity
and bone
Calcified soft tissue
formation;there
component
is matrix
calcification
Ewing's sarcoma
T spine
Vertebral
body
<30
Permeative appearance-
Same as x-ray
Soft tissue mass
lytic lesion with
peripheral
sclerosis.
vertebral
collapse
Chordoma
Cor S spine
Vertebral
body
50-70
Lytic lesion with minor
Same as x-ray
Soft tissue
(anterior
elements)
calcification
mass-little
periosteal
reaction
Chondrosarcoma
TLS spine
Vertebral
bodies
10-90
Lytic lesion with
Same as x-ray
Soft tissue mass
sclerotic margins
Lymphoma
CTLS spine
Anterior
elements
40-60
Lytic lesion
Same as x-ray. soft
Soft tissue mass
tissue mass
Paraspinal soft
TL spine
Posterior elements
>50
Bone erosion
Soft tissue mass
T2 images allow
tissue sarcoma
with bone erosion
delineation of
tumor
margins
(high signal) and
surrounding soft
tissue

49
Tumorsofthe ThoracolumbarSpine
395
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patients
with
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Lecouvet
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1997:204:
195-199
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AV. PettitJE.
Essential
Hematology.
Oxford:
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1993
42.
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KJ. Braunwald
E. Wilson
JD. Martin
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13th ed. New York:
McGraw-Hill;
1994
43.
Lecouvet
FE. MalghemJ.
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frac-
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Pathogenesis
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frac-
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1776-1782

50
Trauma of the Thoracic and Thoracolumbar
Spine
Darryl DiRisio and Edward
C. Benzel
. Anatomy and Biomechanics
. Classification and Description of Injuries
.
Wedge Compression Fracture
.
Burst Fracture
.
Flexion-Distraction
Injuries
.
Fracture-Dislocations
.
NeurologicalInjury
.
Radiological Evaluation
.
Conclusion
Variousclassification schemes have been reported that de-
scribe mechanisms of injury and the resultant pathology to
the spinal column and the spinal cord. One of the first de-
scriptions of fractures of the thoracolumbar spine was put
forth by Sir Frank Holdsworth in 1953. This led to a better
understanding of these fractures and methods for treat-
ment.1 With the development of computed tomography
(IT), fracturepatterns were further described with reference
to the three columns of the spine, as put forth by Denis.2
Denis separated the spine into three separate columns,
placing more relevance in the ligaments as the supporting
structures (Fig. 50-1). He classified thoracic and thora-
columbar fractures with reference to the three columns,
basing the definition of stability on the preservation of at
least two of them. Tobe consistent, mention of columns in
this chapter refers to the Denis three-column system (e.g.,
anterior, middle, and posterior columns) (Fig.50-1).
Pathology of the spine secondary to trauma can be sepa-
rated into the abnormalities of the spinal column resulting
in biomechanical instability, and to abnormalities of the
neurological system. Both are closely related to the forces
impacting upon the spine at the time of injury. Neurological
396
loss can occur in a delayed fashion, due to instability-
related neural element deformation.
Atthe extremes ofthe spectrum of traumatic spinalin-
juries lie the stable spine and the overtly unstable spine.
The former can be more readily defined than the latter.
The definition of stability (the extent of injury) between
these extremes is sometimes ambiguous. White and Pan-
jabi define clinical stability of the spine as the ability of
the spine under physiological loads to limit patterns of
displacement
so as not to damage or irritate the spinal
cord or nerve roots and to prevent incapacitating defor-
mity or pain due to structural changes.3 The inability to
predict the patterns of displacement under physiological
loads for various fracture types presents a problembe-
cause these determinants
of stability could vary among
individuals. Furthermore, each injury is unique, thus fur-
ther complicating
the clinical stability
determination
process.
This chapter describes the pathology of thoracic and tho-
racolumbar trauma as it relates to structural injury ofthe
spinal column and dysfunction of the nervous system.
Mechanisms of injury are specificallyaddressed.

ALL
ANT
---------.
PLL
Ligamentum
Flavum
MID
POST
ISL
Figure50-1
Bonyanatomy and ligaments of the three columns.
All, anterior longitudinal
ligament; PLL,posterior
longitudinalliga-
ment; ISL.interspinous
ligament.
. Anatomy and Biomechanics
Tounderstand the biomechanics in the pathological state.
onemust have a basic understanding of the physical princi-
plesguiding motion in the normal state. The instantaneous
axisofrotation(JAR)isa theoreticalpointwithinoraround
thevertebra. about which a spinal segment rotates (Fig.
50-2).Therefore.a force applied in line with the JARcreates
norotation of that segment. Aforce applied at a fixed dis-
tancefrom the JARcreates a bending moment (m) that is
equalinmagnitudeto the force(F)timesthe distancefrom
itspoint of application at the IAR(D) (m = F x D). For no
movementof the spine to occur following the application of
aforce.there must exist a moment of equal magnitude but
A
50
Trauma
397
IAR..·
Figure 50-2
The instantaneous
axis of rotation (IAR) is an imaginary
point in or about
a vertebra,
around
which rotation
can occur. At the time
of failure the vertebra
collapses
or deforms
about the IAR,as depicted.
of opposite direction. This counteracts and neutralizes the
applied moment.
Axial load application in the thoracic region is usually
ventral to the JARbecause of the natural thoracic kyphosis.
Jt is usually in line with the JARat the thoracolumbar junc-
tion where the spine is relatively straight. Jn the lumbar
spine. an applied axial load is more dorsally situated be-
cause of the natural lordosis. With anterior column injury.
the JARis usually displaced dorsally so that the hinge
around which rotation occurs in this circumstance is lo-
cated near the dorsal elements (Fig. 50-3A). The opposite
occurs with posterior column injury.4 Surgical reconstruc-
tion of the anterior and middle columns should restore ax-
ial load bearing ability as well as the position of the JAR
(Fig.50-38).
Forces applied to the spine can be quite complex. With
spine fractures. it is useful to consider the fundamental
force applied and its contribution to the injury. Asstated, a
pure axial load that is aligned with the JARresults in no ro-
tation about the JAR(e.g.. no bending moment). Jf great
IAR
B
Figure50-3
(A) The instantaneous
axis of rotation (IAR)is shifted dorsally with anterior column injury. (B) Upon reconstruction.
it once again
becomes shifted
more
anteriorly.

398
Thoracicand Thoracolumbar Spine: Pathology of the Thoracic and Thoracolumbar Spine
enough, the force can result in a typical burst fracture (dis-
cussed later). Anaxial load can create a bending moment if
it is applied ventral to the IAR.This accounts for the more
common compression (wedge compression) fractures found
in the thoracicand thoracolumbar region.
Alap belt injury is a result of distraction, combined with
flexion (flexion-distraction
injury). In this case, there is a
distractive force applied dorsal to the IARthus creating a
bending moment about a point (JAR)that is ventral to the
spine. This point may be significantly ventral to the ante-
rior column, thus creating a fracture-dislocation
type in-
jury with distraction of each of the anterior, middle, and
posterior columns. Rotational forces also often playa role,
especially in motor vehicle accidents, where force applica-
tions are usually quite complex. Rotation is often com-
bined with flexion, distraction, or compression forces, thus
accounting for rotational/burst
or rotational/distraction
type injuries.
.
Anatomical Factors
The regional anatomy of the spine plays a significant role in
the characterization of the vertebral column and neurologi-
cal injury. The predisposition to spinal column failure is re-
lated, at least in part, to the natural curvature of the spine.
Ofadditional importance is that in the mid- to upper tho-
racic spine, the spinal canal diameter is at its minimum.
Therefore, it comes as no surprise that there is a higher per-
centage of complete neurological injuries occurring in this
region.
Multiple factors playa role in the predisposition of the
thoracolumbar junction to injury. The relative immobility
of the thoracic spine creates a long moment arm that is
applied to the thoracolumbar junction. Also, at this level.
the vertebral bodies are still relatively small compared
with those more caudally located. Additionally, the curva-
ture ofthe spine changes from that of kyphosis rostrally to
that of a lordosis in the lumbar region. This accounts for
the relative straightening
of the spine observed at this
level. Finally,in the thoracic region, the middle and poste-
rior columns are reinforced by two additional joints on
each side: (1) the costotransverse joint where the rib artic-
ulates with the transverse process, and (2) the costoverte-
bral joint where the rib head articulates with the middle
column at the dorsal portion of the intervertebral disk and
adjacent vertebrae. The rib cage complex, including the
sternum, provides significant stability to the spine via
these facets.
.
Classificationand Description
ofInjuries
Aclassification scheme for spine fractures was put forth by
Holdsworth,S and was later modified by Denis,2Ferguson
and Allen,6 and others. Recently, an all encompassing
scheme has been provided by Magerland AebL7This classi-
fication scheme is based on the pathomorphological charac-
Table 50-1
Denis Classification ofThoracolumbar
Fracturesand
the Bony/Ligamentous
Columns of Involvement
Fracture Type
Column of Involvement
Compression
Burst
Seat belt (flexion-distraction)
Fracture-dislocation
Anterior column
Anterior
and middle columns
Middle and posterior
columns
All three
columns
teristics of the injury, taking into account a two-column
concept, as originally described by Holdsworth.Theutility
of his scheme is that it facilitates
the conceptualization of
three main mechanisms of force application: (1) compres-
sion, (2) tensile force application, and (3) rotation.Com-
pression forces result in wedge compression
and burst frac-
tures, whereas
tensile forces result in transverse disruption
and distraction.
Rotational
forces
result
in rotational in-
juries, which are often observed
in combination with other
injuries.
The Denis classification
scheme,
which is the simplest
and most clinically practical of commonly used schemes,
describes four injury types (Table 50-1 ).The firstandmost
common fracture is the compression fracture. Withflexion
or lateral
bending,
compression
occurs either ventrallyor
laterally. This results in an eccentric loading of the spine,
causing a focal stress concentration
with an accompanying
focal vertebral body fracture (Fig. 50-3A). Thesecondtype,
the burst fracture, results from the application of apureax-
ialload.
It is differentiated
into five types, depending onthe
nature and extent of end plate involvement, the extentof
lateral orientation of the load, and the presence of arota-
tional component
(Table 50-2).
Confusion arises when describing
flexion-distraction
in-
juries
and those
fracture
dislocations
with a flexion-dis-
traction
mechanism.
Flexion-distraction
is a mechanismof
injury, and if severe enough, can result in a fracture-disloca-
tion. The less severe form of flexion-distraction injury was
described by Denis as a seat belt-type injury.Withthistype
of injury, the ventral ligamentous complex acts as a hinge,
and thus the IARis located at this point (ventralligamen-
tous complex) at the time of injury. If distraction occurs
through the ventral ligamentous complex, a fracturedislo-
cation occurs because all spinal ligaments are disrupted.
The IAR in this situation
is ventral
to the vertebrae at the
time of injury (Fig. 50-4).
A useful
way to categorize
the
two types
of fIexion-
distraction
injuries
would
be to use
the
term flexion-
distraction injury to describe the less severe category
Table 50-2
FiveTypesof Burst Fractures as Described byDenis
1. Fracture of both end plates
2. Fracture of superior end plate (most common)
3.
Fracture of inferior end plate
4. Burst rotation fracture
5. Burst lateral flexion-unilateral
burst fracture

50
Trauma
399
A
8
c
Figure50-4
Theinstantaneous axisof rotation (IAR)locationwiththree types offlexion-distraction mechanismsof injury.(A)Allthree elements
aredisrupted, and this is thus categorized as a fracture-dislocation
with a flexion-distraction
mechanism. (8) The anterior longitudinal ligament acts
asa hinge. This is a flexion-distraction
type of injury. (C) With the posterior longitudinal ligament acting as a hinge, anterior compression results.
wherethe anterior longitudinal ligament (ALL)acts as a
hinge.Within this category exists the cIassicalIy described
Chancefractures. The more severe form of injury where all
three ligaments are disrupted should be described as a
fracture-dislocationwith a flexion-distraction mechanism.
Theother two subtypes of fracture-dislocations
include
thosewith a shear mechanism and those with a flexion-ro-
tation mechanism (Fig. 50-4). When the IARis located
ventralto the spinal column a fracture-dislocation
occurs
(Fig.50-4A). If the IARis located at the ventralligamen-
toushinge, a Chance fracture occurs (Fig. 50-48). When it
ismoredorsally located, a wedge compression fracture can
occur(Fig.50-4C).
. Wedge Compression Fracture
Thisfractureoccurswhen the anterior columnfailsunder
compression(Fig.50-3A). The fact that the middle column
remainsintact distinguishes this fracture from the burst frac-
ture.Thisfracture most commonly occurs in the thoracolum-
barjunction because the spine is often flexed in this region.
Thisfracture is commonly found in the thoracic spine
becauseof the natural kyphosis. Apure axial load in this
regioncreatesa bending moment, which,if largeenough,
results in anterior
column failure (Fig. 50-5).
As de-
scribedearlier, the IARin this case is dorsalIy displaced.
Themoment arm thus increases. This exaggerates the
chance for further deformation
folIowing axial loading
(deformitybegets deformity): Most commonly, failure oc-
cursat the superior end plate and is often less than 50%.
Whenradiographs reveal greater compression. one has to
be concerned that middle column failure has occurred.
Preservationof neurological function with this fracture is
common.If neurological function is lost. one has to be
concernedwith the possibility of a concomitant disk her-
niation.
'M
Figure 50-5
Compressionfracture depicting the increasedmoment
arm. as the instantaneousaxisof rotation (IAR)isposteriorlydis-
placed.
.
Burst Fracture
A burst fracture is created by a pure axial load and com-
monly results in neurological deficit because bone frag-
ments are propelIed into the spinal canal at the time of in-
jury. Tran et al9 found that spinal canal compromise was
most affected by loading rate, thus strengthening the argu-
ment that neurological dysfunction occurs at the time of

.
400
Thoracic and Thoracolumbar Spine: Pathology of the Thoracic and Thoracolumbar Spine
impact, rather than being secondary to persistent spinal
canal encroachment by fragments. Additionally,Limbet altO
observed a significant correlation between injury severity
score and neurological compromise, but no correlation be-
tween extent ofspinal canal compromise and extent of neu-
rologicalinjury. Others back up this assertion, finding little
relationship between the two, except in the most severe
cases.11
Different types of burst fractures have been described.
The most common fracture is that of a superior end plate
burst, with retropulsion of the dorsal rostral fragment
(Table 50-2). This is usually associated with a sagittal split
of the caudal aspect of the vertebral body. With this partic-
ular fracture, a fragment is often displaced dorsally between
the pedicIes, which are often splayed open (Fig. 50-6).
There is also often a concomitant sagittally oriented lamina
fracture as well. In biomechanical terms, these fractures are
not always unstable. However, with loss of the anterior col-
umn integrity, they may be prone to instability. Once again.
with loss of height of the anterior column, the IARis shifted
dorsally. Axial loads located ventral to the vertebral body
are applied through a longer moment arm, which poten-
tially worsens an already present kyphosis. It is for this rea-
son that long dorsal instrumentation strategies have often
been employed to counteract or offset this bending mo-
ment. Alternatively, reconstruction of the anterior column
could be utilized, thus displacing the IARback to its more
ventral position and obviating the need for a long dorsal
construct. Furthermore, the latter strategy often preserves
motion segments (Fig.50-38).
The posterior longitudinal ligament is intact with most
burst fractures, so that the retropulsed
fragments
can
occasionally be reduced via stretching of the ligament if
performed early after the injury. The act of reducing a
fracture in this manner is known as ligamentotaxis
or
annulotaxis.
.
Flexion-DistractionInjuries
Flexion-distraction injuries result from tension placed on
the spine via a combined flexion and distraction mecha-
nism. Theoriginal description by Chance was that of an os-
seous fracture extending through the spinous processes,
pedicIes, and portions of the vertebral body (Fig. 50-7).8
This description was expanded by Smith and Kauffer12
Figure 50-6
Burst fracture, axial view. Note the presence ofthepos-
terior superior cortex between the pedicles.
who termed the fracture a Chance fracture.Theyalso
appreciated the association of this fracture with thewear-
ing of a lap belt at the time of injury. At this time,however.
compression injury of the vertebral body was not recog-
nized.
Gertzbein and Court-Brown described flexion-distraction
injuries involving the vertebral bodies. They noted ahigh
incidence of compression fractures associated with these
injuries, and hypothesized that this was secondary toex-
treme flexionofthe spineat the timeofinjury.11Associated
burst fractures (occurring in -15% of cases) were thoughto
occur either during the initial loading or as a secondary
mechanism (axial loading) after all the dorsal supporting
structures were already injured by the primary mechanism
(flexionand distraction).
The compression (burst) fracture associatedwith this
fracture type complicates the decision-making process.The
distractive nature of the injury necessitates the application
of a dorsal compressive force by the construct. However,the
associated burst fracture displaces the IARdorsally,thuspo-
tentially resulting in a greater bending moment application.
Therefore, a combined ventral and dorsal reconstructionis
often required to achieve a biomechanically sound con-
struct.

50
Trauma
401
(
...
......
~/...
....
')
. Fracture-Dislocations
Asdescribed by Denis, fracture-dislocation is a manifesta-
tionof failure of all three columns (Fig. 50-8). With flex-
ion-rotationinjuries, there is severe posterior and middle
columndisruption. Holdsworth described the flexion-rota-
tioninjuryas consisting of a slice fracture of the rostral as-
pectofthe involvedvertebra,and distractionor separation
ofthespinous processes.s With shear injuries, observed in
lumberjacksby Denis and Burkus,13the mechanism of in-
jurywasdescribed as hyperextension. This was usually as-
sociatedwithblunt injuryto the dorsalchestwall.Ribfrac-
tures,pulmonary contusions, and pneumothoraces
were
alsocommonfindings.The third subcategoryis that of a
1
J
B
Figure 50-7
Flexion-distraction
injury. (A) Pure osseous in-
jury or "chance" fracture. (8) Ligamentous rupture. (C) Mecha-
nism of injury.
fracture-dislocation with a flexion-distraction
mechanism
(Fig. 50-8A). This probably represents a more extreme seat
belt injury, with involvement of the disk space. The super-
jacent vertebra is thus allowed to sublux on the vertebra
below.
Allthree types of fracture-dislocation are associated with
severe neurological deficits. In Denis's series, 50%of these
patients had a complete neurological injury, 25%were neu-
rologically intact, and -25%of the patients had partial neu-
rological injuries.2
These fractures at times may reduce spontaneously, and if
purely ligamentous, may be missed radiographically. Clues
to severe injuries include associated rib or transverse
process fractures, and significant internal injuries.

402
Thoracic and Thoracolumbar Spine: Pathology of the Thoracic and Thoracolumbar Spine
A
. NeurologicalInjury
B
Thetype of neurologicalinjury occurring with thoracic lum-
bar trauma is dependent, in part, on the segmental level of
the injury. Higher percentages of complete spinal cord in-
juries are found in the mid-to upper thoracic spine. This is
secondary to the smaller spinal canal diameter, combined
with the greater forces required to injure the intrinsically
stable thoracicspine.Atthe thoracolumbar junction, injuries
to the conus medullaris and to the surrounding nerve roots
occur. Eachinjury can result in a lower motor neuron clinical
picture; however,nerve root (e.g.,cauda equina) lesions cer-
tainly have a greater likelihood of the eventual return of
neurological function (Table50-3). Acute loss of neurologi-
cal function after spinal injury has a worse prognosis than
delayed loss of function. The exception is that found in chil-
dren with spinal cord injury without radiographic abnor-
malities (SClWORA).These children often present with nor-
mal spine radiographs but with neurological injury that
manifests itself at the time of the initial trauma. Half of
these children were found to progress over a 4-day period to
complete paralysis, with a resultant poor prognosis.14
Figure 50-8
Flexion-dislocation injury. (AI
Flexion-distraction mechanism with all three
columns
involved.
(8)
Shear
injury.
(e)
Flexion-rotation combined witha burst fracture
(lateral view). (D) Flexion-rotation
mechanism
combined with a burst fracture (dorsal view).
Neurological
dysfunction
following
spinal cord injuryis
often described as complete or incomplete. Within48hours
of initial injury, it is often difficult to completely
elucidate
the extent of neurological injury. Nevertheless, a complete
lesion has a very poor prognosis for the eventual returnof
neurological function. Therefore, the absence of motoror
sensory function bodes a very poor prognosis, with the high
likelihood for permanent,
complete
paralysis.
Incomplete
lesions usually improve, with approximately
two thirds
of those afflicted
improving
significantly with
time. Complete
motor loss with sensory sparing represents
a situation
with
a good chance
for some
improvement.
However, complete
sensory
loss with
motor preservation
(rare) represents a situation where rapid and completere-
covery is very likely.ISVarious additional syndromes orin-
complete
injuries
have been
described
but have limited
utility for predicting outcome (Table 50-4).
There is a high incidence of neurological
injury associated
with burst fractures, though evidence exists that the neuro-
logical dysfunction
is predominantly
related to the severity
of the spinal column injury and not related to the presence
of bone or soft tissue
fragments
within
the spinal canal.

50
Trauma
403
Table50-3
Conus Medullaris versus Cauda Equina
Involvement
Table50-4
IncompleteInjuriesto SpinalCord
BrownSequard
Ipsilateralweakness
Contralaterallossof painand temperature
Ipsilateralossofsofttouch and proprioception
CentralCord
Lossofupper extremityfunction
Distal> proximal
Extremity
Lossofsensationofthe hands
Sensorydissociation
Anterior Cord
Loss of motor/pain and temperature
Preserved proprioception,
softtouch
Prospective controlled
trials have not determined
that sur-
gicaldecompression of the spinal canal results in improve-
mentof neurological function. Few, however, dispute that
progressiveneurological
dysfunction
is an indication for ur-
gentspinal canal decompression.
Others have found a cor-
relation between
spinal canal compromise
and future pro-
gressiveneurological
deficit. Hashimoto
et al found that the
extent of spinal canal compromise
of 35% at the epiconus
medullaris level, 45% at the conus level, and 55%at the level
ofthe cauda equina were significant factors for neurological
impairment.16
.
Radiological Evaluation
Followingthoracic or thoracolumbar trauma, radiological
evidenceof pathology can often be found on plain radi-
ographsandCT.However,thoughthese methodsare sensi-
tivefordeterminingthe presence of bony abnormalities,
ligamentousdisruption can often be missed. Magnetic reso-
nanceimaging (MRI),utilizing fat suppression strategies,
can often reveal injury to ligamentous structures. Terk
et ap7found a 42%rate of dorsal ligamentous injury associ-
ated with burst fractures of the spine when MRIwas per-
formed within 2 days of injury. This was detected by the
presence of a high-signal intensity obtained on T2 imaging,
utilizing a fat suppression sequence. Of course, the other
utility of MRIresides in its ability to image neurological
structures
and detect the presence of disk herniation,
hematomas, and compression ofthe spinal cord.
Axial CT images are useful for the detection of spinal
canal compromise by fragments ofbone and provide a sen-
sitive method for determining whether a bony injury exists
(Fig. 50-6). With sagittal reformatting, one can obtain in-
formation regarding overall spinal canal alignment, espe-
cially in regions of the spine traditionally difficult to image
by plain radiography, such as the upper thoracicspine.
. Conclusion
Anatomical factors, mechanisms of injury, and level of in-
jury all play key roles as determinants of the pathology in
traumatic spinal injuries. Four fracture types have been de-
scribed, along with their mechanisms of injury. Generally,
loads applied to the spine can be broken down into four
main components: (1) axial compression, (2) tension, (3)
translation, and (4) rotation.6 Allinjuries to the spine can be
explained by either one of these forces or a combination
thereof.
Compression and burst fractures differ in that, in the for-
mer, the axial load is applied more ventrally than in the lat-
ter, thus creating a bending
moment.
Because of the
kyphotic nature of the thoracic spine, compression fractures
are more commonly found in this location. Aburst fracture
is more likelyto be associated with neurological deficit. Dis-
persion of the fragments varies, but severe retropulsion of
the rostral fragment between the pedicles is most com-
monly observed.
In most cases, flexion-distraction
injuries result from
forces applied about a fixed element (e.g.,a seat belt), creat-
ing a bending moment around this structure, and thus flex-
ion and distraction of the spinal elements. Ifdistraction oc-
curs through the ventral ligamentous complex, the injury
fallsinto the category of a fracture-dislocation.
Injury-generating
forces are quite complex, such that
rotation can often occur with a distraction injury, or even
with axial loading. The determination
of load orientation
occurring at the time of injury plays a crucial role in spine
reconstruction,
in that oppositely oriented forces should
usually be applied to restore and maintain spinal align-
ment.
The extent of neurological injury varies,depending on the
extent of spinal column involvement. Additionalfactors that
must be assessed include the presence or absence of a com-
plete injury and whether the patient is neurologically dete-
riorating. Certainly,except in rare circumstances, the major-
ity of neurological injury occurs at the time of impact and is
not significantly related to the presence of persistent spinal
canal compromise. Injury to the cauda equina carries a good
prognosis for recovery. Injury to the conus medullaris car-
ries a worse prognosis; however, incomplete injuries often
Conus Medullaris
Cauda Equina
Motor deficit
Symmetric loss in
May be asymmetric;
appropriate
flaccid paralysis
distribution
Sensory
Saddle anesthesia;
Saddle anesthesia; may
sensory dissociation,
be asymmetric
usually symmetric
Pain
Rare
Usually quite prominent
Reflexes
Decreased ankle reflex
Decreased ankle reflex
Preserved knee reflex
Decreased knee reflex
Bowel/bladder
Flaccid bladder
Flaccid bladder
Overflow incontinence
Overflow incontinence

404
Thoracic and Thoracolumbar Spine: Pathology of the Thoracic and Thoracolumbar Spine
significantly improve. Finally,anatomical variations of the
spinal canal playa key role in the extent of neurological in-
jury, with a higher percentage of complete injuries occur-
ring at the mid- to upper thoracic region because of the as-
sociated limited spinal canal diameter.
Having knowledge of the mechanism of injury and the
degree of neurological deficit enables one to, in a logical
manner, plan reconstructive efforts such that the ultimate
References
1.
Holdsworth
FW. Hardy A. Early treatment
of paraplegia
from frac-
tures of the thoracolumbar
spine.jBjS
1953;35-B;340-350
2.
Denis F.The three column
spine and its significance
in the classifica-
tion of acute thoracolumbar
spine injuries. Spine 1983;8;817-831
3.
White M. Panjabi
MM. Clinical Biomechanics
of the Spine. 2nd ed. .
Philadelphia:
Lippincott;
1990: 1-125
4.
Benzel EC.Biomechanics
of Spine Stabilization:
Principles and Clinical
Practice. New York: McGraw-Hili;
1995:55 B 71
5.
Holdsworth
FW. Fractures,
dislocations
and fracture
dislocations
of
the spine.j
Bone joint Surg Am 1970;52:1534-1551
6.
Ferguson
RI..Allen BL.A mechanistic
classification
of thoracolumbar
spine fractures.
Clin Orthop
1984; 189:77
7.
Magerl F, Aebi M. A comprehensive
classification
ofthoracic
and lum-
bar injuries.
In: Aebi M. ThalgottjS.
Webb.jK,
eds. AO ASIF Principles
in Spine Surgery.
Berlin: Springer Verlag; 199:20-41
8.
Chance CQ. A note on a type of flexion
fracture
of the spine. Br j Ra-
dio11948;21
:452-453
9.
Tran NT,Watson NA, Tencer AF,et al. Mechanism
ofthe
burst fracture
in
the
thoracolumbar
spine:
the
effect
of
loading
rate.
Spine
1995;20:1984
10.
Limb D, Shaw DI.. Dickson RA. Neurological
injury
in thoracolumbar
burst fractures. j Bone joint Surg Br 1995;77:774-777
goal of preservation of neurological function and themain-
tenance of spinal stability can be achieved. Certainly,the
complexity of some injuries defies description. Neverthe-
less, armad with the knowledge of a few biomechanical
principles, appropriate management and reconstructiveef-
forts can be undertaken so that the spine approximatesthe
nonpathological state in resisting deformity, limitingpain.
and optimizing neurological function.
11.
Gertzbein
SD. Court-Brown
CM. Flexion-distraction
injuries ofthe
lumbar
spine:
mechanisms
of injury
and classification.
ClinOrthop
1988;227:52-60
12.
Smith WS, Kaufer M. Patterns
and mechanisms
oflumbar injuriesas-
sociated
with lap seat belts. j Bone joint Surg Am 1969:51 :239
13.
Denis F, Burkus jK. Shear
fracture-dislocations
of the thoracic and
lumbar
spine
associated
with
forceful
hyperextension
(lumberjack
paraplegia).
Spine 1992;17:156-161
14.
Pang D. Wilberger
jE. Spinal cord injury without
radiographic abnor-
mality in children.j
Neurosurg
1982:57:14
15.
Haher TR. Felmy WT. O'Brien M. Thoracic
and lumbar fractures: diag.
nosis and management.
In: Bridwell
KH, DeWald RL.eds. The Text.
book of Spinal Surgery. Philadelphia: Lippincott: 1997:1763B1837
16.
Hashimoto
T, Kaneda
K. Abumi
K. Relationship
between traumatic
spinal canal stenosis
and neurologic
deficits
in thoracolumbar burst
fractures.
Spine 1988;13:1268
17.
Terk MR. Hume-Neal
M. Fraipont M. et al. Injury of the posterior liga.
ment
complex
in patients
with
acute
spinal
trauma:
evaluation by
MR imaging. AjR Amj Roentgenol1997;
168: 1481-1486

51
Lateral Transthoracic Approach to the Spine
DavidHart,
LarryT.Khoo,and
SrinathSamudrala
. Indications
. Contraindications
. Advantages
. Disadvantages
. Anesthesia
.
Surgical Techniques
Positioning
Approach
Thischapteraddresses the standard lateral transthoracic/
thoracotomy approach for anterior exposure of the tho-
racicspine. This approach affords excellent visualization
andworking space for pathologies afflicting the spinal col-
umnfrom approximately T5 to T12. Other, specialized ap-
proaches for anterior
exposure
of the cervicothoracic
junction,upper thoracic spine (T1-T4), and thoracolumbar
junction.
including
transclavicular,
transmanubrial/
transsternal, and combined transthoracic/retroperitoneal
approaches, respectively, are addressed in separate chap-
ters.There are also thoracoscopic approaches and the pos-
terolateral transthoracic approach, through the trapezius
and latissimus dorsi muscles, that are discussed else-
where.
The surgical technique for thoracotomy was first de-
scribedfor partial lobectomy in a patient with bronchiecta-
sisin 1917.The first reported series of thoracotomies for
transthoracic access to the spine was initiated by Hodgson
andStockin 1956, and they described their first 100 cases
in1960.1These were performed for spinal decompression
andfusion in the treatment of tuberculosis. Since this time,
advancesin surgical instruments and technique, anesthesi-
ology,and critical care management
have dramatically
reducedmorbidity and mortality associated with this ap-
proach.The procedure may now be considered one of first
choicein a wide variety of clinical settings.
Incision
Dissection
Closure
.
PostoperativeCare
.
Complications
.
Conclusion
.
Indications
The transthoracic approach may be considered for treat-
ment of multiple categories of pathology affecting the tho-
racic spinal column, including:
.
Diskherniations
.
Anterior release and/or instrumentation
for deformity
correction
. Decompression,fusion, and/or instrumentationfor
spinal fractures
.
Neoplasms
.
Infections such as osteomyelitis
. Abscess
.
Biopsies (in certain circumstances), although in some
quarters this could be supplanted by the use of mini-
mally invasive techniques such as thoracoscopy
.
Contraindications
.
Advanced age
.
Poor pulmonary function
.
Severelydebilitated/medically frail patient
405

406
Thoracicand Thoracolumbar Spine:Antero/Anterolateral Approach
. Lifeexpectancy of less than 3 months (often a consider-
ation in patients with spinal metastases)
.
Damaged mediastinal structures (e.g.,esophageal viola-
tion) in trauma patients
Other considerations, while not strictly contraindications,
include previous thoracotomy, which may have resulted in
excessivescarring and adhesions, or predominantly poste-
rior spinal pathology, which may suggest an alternative
such as the lateral extracavitary or purely posterior ap-
proach.
.
Advantages
. Wide visualization
.
Accessto multiple levels if needed
.
Fullaccess to most pathology of the anterior column
.
Goodanterior access
.
Disadvantages
.
Potential morbidity of thoracotomy (see Complications
section)
.
Need for chest tube postoperatively
. Difficultywithextremebody habitus
(in very small in-
dividuals, the access corridor through the chest wall
may be too small without removing additional ribs; in
very large individuals, the surgeon may have to work in
a deep hole, requiring specialized, longer instruments
for the spine work)
.
Anesthesia
The patient should be intubated with a double-lumen en-
dotracheal tube to facilitate later deflation of one lung,
with continued adequate ventilation of the opposite lung.
Depending on the preference of the anesthesiologist,
a
trial of ventilation
with
one
lung deflated
may be
performed prior to positioning to ensure the patient will
tolerate this.
.
SurgicalTechniques
Positioning
Ifan appropriate radiolucent table is available, this will al-
low obtaining radiographs in two planes, which may be de-
sirable for some procedures. Some prefer using a table that
can be broken, which may provide greater access during
the approach. It is recommended that if instrumentation is
planned, however, that there be a reliable way to return the
table to a true flat position to avoid fusing the spine in a
scoliotic position. Some surgeons avoid breaking the table
altogether
for this reason. There are several key points that
are critical in the positioning
of patients
in the lateral de-
cubitus position (Fig. 51-1). First, attention
must be paidto
ensuring
that the patient
is in true lateral position, with
shoulders
and hips in line perpendicular
to the floor.Any
twisting
of the hips relative to the shoulders will result ina
rotatory
deformation
with or without
scoliosis to a slight
degree
and may make radiographs
more difficult to inter-
pret. Fusion in this configuration
may also cause postoper-
ative pain due to slightly altered biomechanics at thelevel
of fusion.
Furthermore,
a patient
that
is secured to the
table in a tilted position
may be more likely to roll overif
the table is rotated.
Another
key issue is padding of pres-
sure points. An axillary roll to support the chestwall,
thereby
relieving pressure
on the shoulder, should be com-
bined with an "airplane" support for the upper arm,which
is flexed at 90 degrees.
Note that the axillary roll should
not actually
be in the axilla, which might lead to shoulder
pain postoperatively,
but one or two fingerbreadths
below
the axilla on the chest wall. The downside
arm may be kept
Figure 51-1
Demonstration
of patient positioning for anterolateral
transthoracic
approach to the spine. Note head support, optionalkid-
ney rest, airplane for topside arm, axillary roll, configuration of legs
with compression devices to prevent deep venous thrombosis, andpil-
lows under pressure points.

51
LateralTransthoracicApproach
407
straight or very slightly bent, as long as hyperextension of
the elbow is avoided. Both upper extremities should be
resting in a way such that the ulnar nerve, vulnerable to
pressure at the elbow, is not damaged. The head must be
supported on a cushion, to maintain cervical spine align-
ment without lateral bending. Padding should also be ap-
pliedto the downside hip, ankle, and knee, to include the
fibular head, where the peroneal nerve is vulnerable to
pressureinjury. The downside leg should be flexed to help
stabilizethe patient (note that for a retroperitoneal ante-
riorapproach to the lumbosacral spine, this should be re-
versed, with the upside leg bent to relax the ipsilateral
psoas muscle, which must be retracted
during the ap-
proach),with a pillow placed between the knees. The up-
sideleg may be straight or slightly bent. The patient may
be maintained in the lateral position with the surgeon's
choiceof techniques, including a kidney rest (with care
taken to keep it out of the path of x-rays), a beanbag,
and/ortape across the hips. Although beanbags are very
convenient in positioning, some surgeons feel they are
dense enough to make x-rays difficult to interpret
and
therefore avoid them. If the incision is to be made low
enough,tape may also be placed across the upper chest
walljust below the axilla, with care taken to ensure that it
isnot tight enough to restrict ventilation. Antithrombo-
genicstockings and/or compression devices are recom-
mended,as well as Foley catheterization.
Somatosensory
evokedpotential recording should be initiated prior to the
startofthe surgery (see discussion under Complications).
Approach
Thepatient may be positioned in the right lateral decubitus
positionfor most situations. However, familiarity with the
intrathoracic anatomy and the nature of the patient's
pathologymay sometimes lead to a choice of a left-sided
approach.Forexample, a lower thoracic lesion that may re-
quireconversion to a thoracoabdominal approach would be
severelylimited by the presence of the liver in many cases
witha right-sided approach. Another consideration is that
exclusivelyleft-sided pathology, such as a left lateral disk
herniation,would often be better approached from the left.
Thisrequires awareness of the course of the thoracic duct,
whichcrosses from right to left at or about the level ofT5.
Obviouslythis structure must be accounted for in a right-
sided approach below T5 as well. Another important
anatomicalconsideration regards the segmental vascula-
ture.The radicular and intramedullary
blood supply be-
comesrelatively sparse in the "watershed zone" from 13 to
T9,leaving this area of the spinal cord susceptible to is-
chemicinsult. This issue will be revisited during the proce-
duredescription. Finally, if the case involves a deformity
correction,the standard rule is that the approach should be
fromthe convexside.
Incision
Althoughmany spine surgeons prefer to allow a thoracic
surgeonto perform the thoracotomy, obviously familiarity
with the exposure
is necessary
regardless
of who is
Figure51-2
The location of the planned incision, with an example
of pathology at the level of T8. Note that the incision is made along
the course of the rib two interspaces above the vertebral level,
although this canvary (see text). The incision is performed from the
anterior
border
of the
latissimus
dorsi to the
costochondral
junction.
performing it. The skin incision is curvilinear along the
path of the rib, from the anterior border of the latissimus
dorsi muscle to the costochondral junction anteriorly (Fig.
51-2). The ribs may be counted by palpation, although a
chest x-ray is advised as part of the preoperative planning.
Asa general rule, the incision and subsequent route of en-
try into the chest should be centered on a rib two levels
above the level of spinal pathology. Thus,for a lesion at T8,
the sixth rib would provide optimal access.Within the bell
curve of the population, however, some patients' ribs will
travel much more vertically or horizontally than usual-
again, the chest x-ray should be illustrative. Some surgeons
tape a paper clip or other suitable marker over the rib at
the planned entry site and obtain a lateral x-ray prior to
prepping to double-check the appropriate level. Infiltration
of lidocaine with or without epinephrine is optional. A
suitable antimicrobial skin preparation and draping are
performed. Intravenous preoperative antibiotics should be
given as desired.

408
Thoracicand Thoracolumbar Spine: Antero/Anterolateral Approach
Dissection
The skin is incised down to subcutaneous tissue. Dissection
with electrocautery is carried down to the periosteum
overlying the rib, which is then incised with the cautery
(Fig.51-3). Depending on the patient's body habitus, it may
be necessary to undermine and/or incise the anterior edge
of the latissimus dorsi to widen the opening. The perios-
teum and intercostal musculature are then stripped from
the rib (Fig. 51-4). It is important to avoid disrupting the
neurovascular bundle, which is at the inferior aspect of each
rib, tucked into a groove on the inner aspect of the rib.
Stripping the rib is greatly facilitated by accountingforthe
directional nature of the intercostal muscle attachments:
Blood loss and tissue trauma, not to mention operative
time, will be reduced by stripping from posteriorto anterior
on the cephaladaspectofthe rib,andfromanteriortopos-
terioron the caudadsurface.Theribiscutat thecostochon-
dral junction and as far posteriorlyas possible,thenre-
moved. It may be saved as bone graft if desired.The
intercostal
muscles and neurovascular bundle are pre-
served,left attached to the parietal pleura (Fig.51-5).The
pleura is then opened along the path of the originalinci-
sion, between the intercostal muscles.
Figure 51-3
Exposure of the rib, after incision
through
skin and subcutaneous
tissue. Undermining
the latissimus dorsi will reduce
bleeding, but it may
need to be incised in part.
A
B
c
~
--
D
Figure 51-4
(A) The periosteum
is stripped off the surface of the rib with monopolar electrocautery
and/or a periosteal elevator. (B.C)Theinter-
costal muscles are stripped from the rib. Note the directional nature of the attachments
(see text). (D) The rib is removed with a rib cutter.

51
LateralTransthoracicApproach
409
Atthis point, the lung is deflated, and time is allowed for
the anesthesiologist to ascertain adequacy of ventilation
and oxygenation. A rib spreader
is then inserted
and
crankedopen, allowing the widest possible access corridor
intothe chest cavity. In cases where multiple levels of the
spinemust be accessed, additional rib(s) may be removed
insimilar fashion prior to opening the pleura. The lung is
gentlyretracted anteriorly and inferiorly and may be pro-
tectedwith a moist laparotomy sponge (Fig.51-6).
The parietal pleura overlying the vertebral column is
then incised vertically along the lateral aspect of the ante-
rior longitudinal ligament, taking care not to disrupt the
segmental vessels. They are easily identified, running hor-
izontally along the deepest portion of the concave verte-
bralbody, midway between the prominently convex disk
spaces.These vessels should, after identification, be care-
Figure51-6
Surgeon's viewat a slightlylater point inthe exposure,
withthe pleura overlyingthe spine incised,and the segmental vessels
alreadyligated(seetext).
Figure 51-5
Following removal of the rib, the
adjacent
intercostal
musculature
and neurovas-
cular bundle are preserved on the pleural surface.
The course of the pleural incision is noted.
fully ligated and divided. This allows blunt dissection
acrossthe vertebral body and adjoiningdisk spaces,leav-
ing only the anterior
longitudinal
ligament and anulus
(Fig. 51-7). Some prefer to perform this dissection with
the monopolar
electrocautery,
although
great care is
Figure 51-7
Demonstration
of the anatomy of the anterolateral ver-
tebral column as it would be seen with all overlying periosteum
and
pleura stripped away. Note the anatomical relationships of the sympa-
thetic chain, as well as the disk spaces and foramina relative to the seg-
mental vessels.

410
ThoracicandThoracolumbarSpine:Antero/Anterolateral Approach
needed when approaching the further lateral areas and
structures (e.g., the sympathetic chain, nerve roots, tho-
racic duct, etc). Leadingthe dissection along the surface of
the relatively avascular disk spaces helps avoid bleeding
and makes it easier to preserve the segmental vessels un-
til they can be identified and ligated. Proceeding in this
way prevents much struggling to control bleeding from
mostly hidden, prematurely disrupted vessels. The great
vessels and esophagus are mobilized anteriorly. Care must
be taken to avoid opening the parietal pleura too far later-
ally, where the sympathetic trunk may be damaged. An-
other caution regards identification and protection of the
thoracic duct. Finally, if multiple levels of the spine are to
be subject to operation, this requires ligation and division
of multiple segmental vessels. This should be undertaken
with care in the earlier-mentioned
watershed zone, and
the anesthesiologist
should be admonished to avoid hy-
potension, lest the patient suffer a spinal cord infarction.
If the lower thoracic spine is involved, it bears recollec-
tion that the artery of Adamkiewicz may be found some-
where between T9 and L2and is on the left side in -60%
of patients.
Avariation on the preceding procedure may be consid-
ered in those patients with a minimum of scar and adhe-
sion of the pleura. In such patients, it may be possible to
perform a retropleural dissection (Fig. 51-8). After remov-
ing the rib, blunt dissection with a finger or sponge stick is
used to strip the parietal pleura off the inner surface of the
chest wall. This can only be successful if the appropriate
plane is entered. There will be periosteum from the deep
surface of the removed rib, and this must be opened with-
out opening the pleura. The blunt dissection is carried
around posteriorly to the rib head, and then to the spine. If
successful, without violation of the pleura, it may be possi-
ble to later avoid a chest tube. The disadvantage of the tech-
nique is that it limits the number of vertebrae that may be
exposed.
Ifaccess to the far lateral aspect of the disk or vertebral
body isrequired, the rib head may be resected, exposing the
pedicle, foramen, and transverse process. The pleura and
periosteum over the rib head are incised, again takingcare
to avoid damaging
the sympathetic
chain. The costoverte-
bral and costotransverse ligaments are incised,allowingre-
moval of the rib head with transection -2 cm distal tothe
head (Fig. 51-9). At this point, the approach to the spineis
complete.
With this kind of exposure, a wide variety ofprocedures
may now be performed with relative ease and goodvisual-
ization. Diskectomies,
corpectomies,
anterior instrumenta-
tion, fusion, biopsies, deformity
correction-any
and allcan
be readily performed.
The techniques
for these procedures
are beyond the scope of this chapter and can be foundelse-
where.
Closure
Upon completion of the spine work, attention mustbe
turned
to closure of the wound. The parietal pleura overly-
ing the spine should be closed with interrupted absorbable
sutures,
if possible.
Depending
on the extent of spinalin-
strumentation
and bone work, it may not always be possi-
ble to close completely. In some cases this can be overcome
by mobilizing the pleura further laterally prior to closure.A
chest tube, somewhere between a no. 28 and 32 French,
should be placed to the apex under
direct visualization. In
certain situations,
such as when there is significant postop-
erative bleeding expected or the pleura cannot beclosed
over the spine, it is helpful to place a second chest tubeat
the base of the lung as well. The chest tube(s) are tunneled
subcutaneously and brought out through separate smallin-
cisions one interspace
away from the operative incision.Be
certain to bring the tube(s) out just above the ribtoavoid
the neurovascular bundle at the inferior lip.Thechestwall
retractor is removed and the lung reinflated under directvi-
sualization. Confirm that all lobes of the lung appearwell
inflated. Ifonly one rib was removed, the adjacent ribsare
then approximated with a few sturdy sutures aroundthem.
Once again, take care when passing the sutures to avoidthe
neurovascular bundles. Arunning absorbable suture isthen
used to close the pleura. If it is particularly friable,the
Figure 51-8
Alternative, extrapleural dissec-
tion forthe transthoracic approach. See text for
details.

I
51
LateralTransthoracicApproach
411
intercostalmuscles may be included for extra strength. The
woundis copiously irrigated, the latissimus dorsi is reap-
proximated if it was cut, then the subcutaneous
tissue
is
closedand the skin is closed with a subcuticular running
stitchand sterile tape strips, or with skin staples as per the
surgeon'spreference.
The chest tube(s)
are secured
to the
skinand the wound is dressed.
Afterremoval of the drapes,
the chest tube(s)
should be
connectedto 20 cm H20 suction and the patient is carefully
returned to the supine
position and extubated
if medically
stablefor extubation. All pressure points should be in-
spected.Postoperatively, be certain to check the patient for
shoulderpain, brachial plexus injury, or peroneal
nerve in-
jury.An upright chest x-ray should be obtained
in recovery
andevery morning thereafter.
. Postoperative
Care
Asidefrom the standard wound care, deep venous throm-
bosisprophylaxis, gastrointestinal
prophylaxis, therapy
evaluations,and mobilization protocols typical of all spine
patients,the particular postoperative care of these patients
focuseson the chest tube management. The patient must be
followedcloselywith serial daily chest x-rays to ensure that
thelungremains inflated and that there is no accumulation
ofa large pleural effusion, hemothorax, chylothorax, or
otherproblems (see Complications section). If the patient
developsa pneumothorax of significance, check to ensure
thesuction apparatus is functioning properly. Ifthe patient
hasa single chest tube, it may be removed at the bedside as
soon as 24 hours postoperatively,
but only once the
drainagehas decreased to less than 100 mLper day. It is ad-
visableto place the chest tube to water seal (Le.,closed sys-
temwithout suction) for at least 6 hours prior to removal of
thetube, with another chest x-ray while on water seal, to
ensurethe patient will tolerate removal of the tube. If the
Figure 51-9
Anatomy ofthe articulation and ligaments between
the vertebra and rib. See text for description of removalof the rib
head, allowingaccessto the neuralforamen and lateralvertebra.
patient had two chest tubes placed, the first (apical) maybe
removed 24 hours postoperatively. The second is main-
tained until the drainage has decreased as already de-
scribed, then placed to water seal, then removed. Oncethe
patient is free of chest tubes, a follow-up chest x-ray must
be checked 4 to 6 hours postremoval. Occlusive dressings
with Vaseline gauze or similar material are applied at the
chest tube sites to prevent air leakage.
.
Complications
With appropriate attention to detail, the lateral transtho-
racic approach is well tolerated by most patients and can
be performed
with minimal morbidity
and mortality.
Many of the potential complications
we have addressed
during the procedure, and they can often be avoided by
adhering to the techniques
described. However, known
complications
have been described in the literature. In
one review of 1223 patients
that underwent
anterior
spinal surgery with 707 thoracic procedures, there was a
0.33%mortality rate (4 deaths from 1223 patients) and an
overall complication rate of 29%.2The documented com-
plications related to the transthoracic approach included
wound
infection,
radiculopathy,
aortic
laceration,
Horner's syndrome, pleural effusion, pneumothorax, and
chronic pain. Other complications such as pseudarthrosis
and dural tear were specific to the spine procedure being
performed. Two patients
in this series (0.16%)suffered
paraplegia after corpectomy and fusion. Although there
are multiple opinions in the literature as to whether the
sacrifice of segmental vessels along the vertebral bodies
can be said to "cause" spinal cord ischemia or infarction,
there is scant evidence to support such a conclusion. Are-
view of 1197 patients in 1996 found only five patients
with postoperative
paraparesis, of which four had me-
chanical
compression
of the spinal
cord.3 However,

412
Thoracic and Thoracolumbar Spine: Antero/Anterolateral Approach
despite the apparent rarity of such catastrophic neurolog-
ical deficit, we do recommend
somatosensory
evoked
potential recording as stated earlier.
Movingout of the spine literature, the thoracic surgery
literature documents complications of thoracotomy includ-
ing hemothorax, chylothorax, brachial plexus injury, lung
herniation, and even highly unusual findings such as renal
failure,sepsis,and pneumocephalus.4-lo
References
t.
Hodgson
AR. Stock FE. Anterior
spine
fusion
for the treatment
of
tuberculosis
of the
spine:
the
operative
findings
and
results
of
treatment
in the
first
100 cases.
J Bone Joint
Surg Am 1960:42:
295-310
2.
Faciszewski
T. Winter
RB.Lonstein JE. Denis F.Johnson
l. The surgical
and
medical
perioperative
complications
of anterior
spinal
fusion
surgery
in the thoracic
and lumbar
spine in adults:
a review of 1223
procedures.
Spine 1995;20:1592-1599
3.
Winter
RB. Lonstein JE. Denis F. Leonard AS. Garamella
JJ. Paraplegia
resulting
from vessel ligation. Spine 1996;21: 1232-1234
4.
Brockmeier
V. Moen H. Karlsson
BR. et al. Interpleural
or thoracic
epidural
analgesia
for pain after thoracotomy:
a double
blind study.
Acta Anaesthesiol
Scand 1994;38:317-321
5.
Brown WM III. Symbas
PN. Pneumocephalus
complicating
routine
thoracotomy:
symptoms.
diagnosis.
and management.
Ann Thorac
Surg 1995;59:234-236
.
Conclusion
The lateral transthoracic approachto the spineaffords a
safe,relativelystraightforwardmeansofaccesstoanterior
pathology of the thoracic spine. With experience andap-
propriate patient selection, it can represent a powerful
technique in the spine surgeon's armamentarium fordeal-
ing with a wide variety of conditions.
6.
DiMarco AF. Oca O. Renston
JP. Lung herniation:
a cause of chronic
chest pain following
thoracotomy.
Chest 1995;107:877-879
7.
Golledge J.Goldstraw
P. Renal impairment
after thoracotomy: inci-
dence.
risk
factors.
and
significance.
Ann Thorac
Surg 1994;58:
524-528
8.
Kalso E. Perttunen
K. Kaasinen
S. Pain after thoracic
surgery. Acta
Anaesthesiol
Scand 1992;36:96-100
9.
Mangar D. Kelly DL. Holder DO. Camporesi
EM. Brachial plexuscom-
pression
from a mal positioned
chest
tube after thoracotomy. Anes.
thesiology
1991 ;74:780-782
to.
Rice TW. Kirsh JC. Schacter
lB. Goldberg
M. Simultaneous
occurrence
of chylothorax
and subarachnoid
pleural
fistula after thoracotomy.
CanJ Surg 1987;30:256-258
Table 51-1
LateralTransthoracicApproach
Advantages
Disadvantages
Wide visualization
Can access multiple levels
Good anterior access
Indications
Degenerative
Herniated disk
OPLL
Spondylosis
Trauma
Traumatic HNP
Fracture/dislocation
Infection
Abscess
Osteomyelitis/
diskitis
Neoplasm
Spinal metastasis
Spinal neoplasm
Other neoplasm with
spinal invasion
Potential
morbidity
of thoracotomy
Need for chest
tube
Difficulty with extreme
body habitus
Contraindications
(Relative)
Advanced age
Poor pulmonary function
Poor medical condition/frail patient
Injured/compromised
mediastinum
Posterior spinal pathology
Previous thoracotomy
HNP. ; OPLL,ossification of the posterior
longitudinal
ligament.

52
Thoracoabdominal Approach and Closure
FaheemA.SandhuandJuanJimenez
.
Indications
.
Contraindications
. Advantages
. Disadvantages
. Objective
Exposureofthe anterior thoracoabdominal spine isoften nec-
essaryfor definitive treatment
of various spinal disorders. The
keyfeatures of this exposure are mobilization or partial mobi-
lizationof the diaphragm,
and entry into both the thorax and
the retroperitoneum.
The approach
is versatile and provides
goodvisualization ofthe anterior spine from no
to L2.
. Indications
. Trauma
. Tumors
. Deformitycorrection (kyphosis. scoliosis)
. Degenerativedisk disease
. Pseudarthrosis
. Osteomyelitis
. Spondylolisthesis
. Failedposterior fusion
. Contraindications
. Medicalillnessthat wouldprecludesurgery
. Previousretroperitonealsurgery
. Advantages
. Versatile approach
.
Good visualization
of and access to the anterior
spine
between Tl0 and L2
.
Minimal disruption
to intraperitoneal
structures
.
SurgicalTechnique
Approach
Position
Incision and Dissection
Closure
.
Complications
.
Disadvantages
.
Entryintothe thoraxand associatedrisks
.
Potentiallypainfulincision
.
Postoperativeileuscommon
.
Abdominalvisceraat riskforinjury
.
Complicationsofthoracotomy
.
Riskofspinalcordinfarction
.
Objective
Thepurpose ofthis chapter is to providethe surgeonwith
an understandingofthe anatomicalrelationshipsrequired
fora standardthoracoabdominalapproachto thespine.
.
SurgicalTechnique
Approach
The thoracoabdominal approach is used to accessTlO-L2.
The spine is usually approached from the patient's left side
because arterial repair is easier than repair of the thin-
walled vena cava. In addition, the liver is more difficult to
mobilize when the approach is from the right. However,the
location of the pathology and surgeon comfort will often
dictate the side of the approach. The use ofa double-lumen
endotracheal tube may aid in selectivelungdeflation.
Position
The position of the patient should be such that the affected
vertebral body is over the bend of the table to enhance ex-
413

414
ThoracicandThoracolumbarSpine:Antero/Anterolateral Approach
posure. The patient is placed in the right lateral decubitus
position.
Incision and Dissection
The entire left side is prepped from the axilla to the iliac
crest. The skin incision is made over the tenth or eleventh
rib from the posterior axillary line extending to the lateral
margin of the rectus sheath (Fig. 52-1). The dissection is
carried
down to the periosteum
proximally
and the
oblique muscles and the transverses
abdominus anteri-
orly. The cartilaginous rib tip is sharply dissected and the
rib is exposed. The intercostal muscles and neurovascular
bundle are stripped
subperiosteally
from the rib (Fig.
52-2). The rib is harvested as far posterior to the costo-
transverse junction
to help with exposure and can be
used as graft material. Care should be taken to avoid in-
jury to the inferior neurovascular
bundle. The thoracic
cavity is entered via the rib bend and the diaphragmatic
attachment
to the ribs is identified. Byblunt dissection,
the retroperitoneum
is entered and a plane established
(Fig. 52-3). Once the diaphragm is free, it is incised at
least 1 to 1.5 cm from its attachment to the rib cage. This
Figure 52-1
A skin incision is made over the tenth rib from the lat-
eral border of the paraspinous musculature to the costal cartilage. The
incision is curved anteriorly to the edge of the rectus sheath.
muscular rim is denervated and must be taggedevery3
cm for later reattachment. Using different-color suturefor
each side of the diaphragm can aid subsequent closure.
The majority of the diaphragm will remain innervatedand
fully functional because the phrenic nerve inserts cen-
trally and radiates peripherally. The undersurface ofthe
diaphragm is bluntly dissected from the retroperitoneum
back to the crus. The pleura is then identified, incised,and
dissected anteriorly, elevating it from the spine withthe
diaphragm. The crus of the diaphragm is also incisedleav-
ing a small cuff on the spine for later approximation.Fol-
lowing placement
of retractors,
nO-L2
should be ex-
posed. A radiograph
is obtained
to confirm the target
level. The lung is deflated and packed and a rib spreaderis
introduced to maximize the exposure. The vascularnet-
work of segmental vessels lie anterior to the vertebral
bodies and these vessels are mobilized and ligated(Fig.
52-4). Two ligatures must be applied on the aorticstump
and ligation must be 1 cm from the vertebral foramento
avoid disruption of the anastomotic
blood supplytothe
spinal cord. Care must be taken
during the ligation
process to avoid injury to the posterior sympatheticchain.
Toallow better visualization of the spine, the proximalat-
tachment of the psoas muscle may be incised anddis-
sected posteriorly with a sharp elevator. At this pointthe
vertebrae
are visualized
and can be dissected to the
neural foramina, pedicle, and anterior longitudinalliga-
ment (Fig. 52-5). Once oriented, diskectomy, decompres-
sion, and instrumentation
can proceed. If indicated,the
vertebral body can be removed after excision ofthe inter-
vertebral disks above and below the operative level.For
acute fractures,the vertebrectomycan be performedwith
a combination of rongeurs and curettes. Ahigh-speeddrill
may facilitate removal of dense bone. After adequatede-
compression is achieved, strut grafting is required forre-
construction and stabilization is achieved with an appro-
priate plating system.
Closure
Closure is initiated by approximating
the diaphragmatic
crus with nonabsorbable suture. The pleura is reapproxi-
mated with an absorbable
suture. A running sutureis
used to approximate
the diaphragm with supplemental
interrupted sutures. Achest tube is placed through asep-
arate stab incision under direct vision through the tho-
racic portion of the exposure to evacuate blood andair.
Two tubes may be necessary, one aimed superiorlyto
evacuate air and one aimed inferiorly to evacuate blood.
The chest tube or tubes are secured with purse stringsu-
tures. The lung is checked for air leaks by filling the tho-
racic cavity with saline. The ribs are approximated to-
gether with heavy suture. The periosteum and intercostal
muscle layers are closed in airtight fashion with running
suture. Adrain in the retroperitoneal space may be placed
but maynot be required.Theperitoneumis allowedtofall
back into place. The transversalis
fascia and aponeurosis
of the transverses abdominus and oblique musclesarere-
paired to prevent hernia formation. The subcutaneous
layers are closed with interrupted
absorbable suture and
the skin with staples.

r
52
Thoracoabdominal
Approach and Closure
415
External
obliquem.
Internal
obliquem.
10thrib
Figure 52-2
The retroperitoneal space is en-
tered
by splitting
the
costal
cartilage
after
removal of the tenth rib.
Figure 52-3
The retroperitoneal space isiden-
tified by the light areolar tissue, and blunt dissec-
tion is performed
to mobilize the peritoneum
from the undersurface
of the diaphragm and ab-
dominal wall. The diaphragm
is circumferentially
incised 2.5 cm from the peripheral attachment to
the chest wall. Marker stitches or clips are placed
for resuturing the diaphragm later.

416
ThoracicandThoracolumbarSpine:Antero/Anterolateral Approach
Figure52-4
The aorta is mobilized byligating
segmental vessels as necessary.
Figure 52-5
The spine is exposed to the oppo-
site cortex by mobilizing
vessles and placing mal-
leable
retractors.
.
Complications
mayresult in herniationofabdominalvisceraintothetho-
rax. Allcomplications of thoracic surgery may occur,includ-
ing atelectasis, pneumonia, pleural effusion, pulmonary
edema, and heart failure. Some patients suffer from postop-
erative thoracotomy or chest wall pain. Hemorrhage, de-
layed or immediate, is possible and may cause spinal cord
compression if in the epidural space. Injury of the artery of
Adamkewicz with resultant spinal cord infarction is possi-
ble if intersegmental arteries are ligated too close to the
neural foramen.
Exposure of two body cavities adds significantly to the risks
of surgery. Abdominal injuries may include injury to the
stomach, colon, kidney,ureter, or spleen. Ileus may also be
anticipated. Peritonitis may result from unrecognized in-
traperitoneal injury and should be suspected if prolonged
ileus and abdominal pain are present. Iatrogenic sympa-
thectomy may also be encountered with resultant limb
warmth asymmetry. Inadequate closure of the diaphragm
I
IIi
I
L

r
53
Retroperitoneal Approach and Closure
JuanJimenez and Faheem A. Sandhu
.
Indications
Contraindications
. Advantages
. Disadvantages
. Objective
Anteriorexposureofthe upper lumbarspineis challenging
dueto the critical structures
located in the abdominal
cavityand thorax. However, numerous clinical situations
dictatethat an anterior approach be taken to treat a patho-
logicalesion. Access to the anterior lumbar spine can be
readilyaccomplished by a retroperitoneal dissection. This
approachposes less risk to the peritoneal organs and great
vesselswhile providing unilateral visualization of the verte-
bralbodyand intervertebral disk space.
. Indications
. Osteomyelitis
. Metastatic tumors
. Primaryvertebral tumors
. Burstfractures
. Scoliosis
. Anteriorinterbody fusion
. Initial
. Afterfailed posterolateral fusion
. Contraindications
. Medicalillness that would preclude surgery
. Priorretroperitoneal surgery
. Advantages
. Goodunilateral visualization and exposure of the ante-
rior lumbar spine between
L1 and 51
. SurgicalTechnique
Positioning
Incision and Dissection
Closure
. Complications
. Minimal disruption to intraperitoneal structures
. Lessrisk to the peritoneal organs and great vessels
.
Disadvantages
.
Risk of injury to vascular structures,
especially with
exposure of lower lumbar levels
. Riskof ureteral injury
.
Objective
Toobtainunilateralvisualizationof the anteriorlumbar
spine from L1to 51
. Surgical Technique
Positioning
The patient is placed in the right lateral decubitus position
for several reasons. It is easier to mobilize and retract the
aorta than the thin-walled vena cava,and ifvesselinjury oc-
curs, repair of the thick-walled aorta is easier than repairing
the vena cava.Also,retraction of the spleen iseasier than re-
traction of the liver.Furthermore, the lateral decubitus posi-
tion allows the peritoneal contents and the great vessels to
fall away from the operative field. Support is applied to the
shoulder, hips, and arms, and the knees are flexed. Use of
electrophysiological monitoring and the CellSaver(Haemo-
netics, Braintree, MA)is recommended. The CellSaver is an
intraoperative salvage device that allows autotransfusion of
red blood cells and thus reduces the need for donor blood
transfusions.
417

418
ThoracicandThoracolumbarSpine:Antero[Anterolateral Approach
Incision and Dissection
The incision is made at the midpoint between the lowest
rib and the iliaccrest from the midaxillary line to the edge
of the rectus sheath. The level of the incision varies de-
pending on the level operated. Ifupper lumbar exposure is
desired, the skin incision is started over the twelfth rib
and extended transversely
around to the anterior
ab-
domen above the level of the umbilicus. To access lower
levels, the incision is made one or two fingerbreadths be-
low the costal margin and carried in an oblique fashion
around the anterior abdomen below the level of the um-
bilicus (Fig. 53-1). The anterior portion of the twelfth rib
is dissected from the latissimus dorsi and serratus ante-
rior. It is resected to facilitate an extensive exposure. The
external oblique fibers are identified and split parallel to
the incision. The fibers of the internal oblique and trans-
versus abdominus muscles are cut in the same direction
as the skin incision. The transversalis fascia is identified
and the posterior portion is opened to access the retroperi-
Figure 53-1
The level of the incision varies according
to the level of
the spine approached.
The patient
is placed in the right lateral decbi-
tus position
with the left side up.
toneal space (Fig. 53-2). The peritoneum
is identified and
dissected
medially from the transversalis
fascia. Peritoneal
injuries
are
more
likely
to occur
lateral
to the rectus
sheath, and tears should be repaired primarily to avoid
bowel herniation. In blunt fashion, the dissection iscarried
along the renal fascia posterior to the kidney in theplane
between the quadratus lumborum. psoas. and renalfascia
(Fig. 53-3). Mobilization of the peritoneum is carriedme-
dially
from the inferior
edge of the kidney down to the
sacrum.
The small-caliber
genitofemoral
nerve is identi-
fied on the belly of the psoas muscle. The cylindrical shape
and peristaltic
activity
help identify
the ureter, whichis
usually
reflected
medially
with the peritoneal
undersur-
face. If upper lumbar exposure is needed. the leftdi-
aphragmatic
crus, which extends
to the second vertebral
body, can be taken
down. Retractors
are brought intothe
field to open the wound longitudinally. The concaveshape,
in contrast
with the convex disk space. identifies the lum-
bar vertebral
bodies. Radiograph
or fluoroscopy is usedto
identify the desired level.
Vertebral
body exposure
requires
lateral mobilizationof
the prevertebral
structures.
The lumbrosacral
plexus islo-
cated within the psoas muscle. Its ganglionic enlargements
and yellow-white
color traversing
in the lateral aspectof
the vertebral body distinguish the sympathetic trunk.In
males,the firstand secondgangliaare involvedin ejacula-
tory function.Arterialand venous anatomymustbe con-
sidered during the exposure (Fig. 53-4). Segmentalarteries
are ligatedand cut prior to their entry intotheneuralfora-
men to facilitate
mobilization
and retraction
of the aorta.
The ascending
venous complex
is located along the lateral
aspectofthe vertebralbody;at the levelofthe neuralfora-
men, segmental veins anastomose with the vena cavaor
common iliac if distal (fifth lumbar vein). These segmental
vessels must be ligated midway between the neuralfora-
men and the parentvesselto avoidavulsioninjury.Ifexpo-
sureofLS-Slis needed,the diskspaceisaccessedbetween
the common iliacvessels. The prevertebral structures(mid-
dle sacral vessels and hypogastric plexus) are bluntlydis-
sected and swept to the opposite side and the iliacvessels
are retracted laterally. Ifextensive lumbosacral exposureis
required or if arterial or venous anatomy prevent interiliac
approach. the common iliac vessels are reflected to the
right. Mobilization of the iliac artery may require ligation
of several branches, and the internal iliac vein alsohas
manytributariesthat shouldbe identifiedandligated.This
exposure
will
allow
access
to
the
lumbosacral
spine
and superior sacrum medial or lateral to the iliacvessels
(Fig.53-5).
Closure
After removal of the retractors, the peritoneum resumesits
normal location. Placement of a suction drain is recom-
mended.Eachmusclelayeris closedwith running,nonab-
sorbable suture; the skin is closed with staples.

53
RetroperitonealApproachand Closure
419
A
\
/
./
Figure 53-2
(A) The skin incision extends from the midaxillary
line to the edge
of the rectus
sheath.
Dissection
is through
the
external oblique. internal oblique. and transversus abdominis muscles.
(8) The transversus
abdominis
muscle fascia is thin and very close to
the peritoneum.
B

420
Thoracic and Thoracolumbar Spine: Antero/Anterolateral Approach
Genitofemoral n.
Figure 53-3
Blunt dissection anterior to the psoas muscle and reflec-
tion of the peritoneum
anteriorly should expose the spine. One should
identify the genitofemoral
nerve on the anterior surface of the psoas
muscle. and the ureter along the undersurface of the peritoneum.
Figure 53-4
The aorta iseasilypalpated and segmental vessels are
ligated formobilization.
Figure 53-5
Malleable retractors are positioned to expose theverte.
bral bodies.
.
Complications
With
use of the retroperitoneal
approach.
injuries canoc-
cur to vascular structures and the bowel and ureter.Injury
to a great vessel can result from congenital anomaliesor
adhesions. Tumors may be well vascularized and a preop-
erative angiogram with embolization
should be doneif
indicated. Injury to a great vessel must be addressedim-
mediately with compression and primary repair to avoid
potential massive hemorrhage. Peritoneal violationcanoc-
cur in the setting of adhesions and scarring fromprior
surgery and radiation in oncology cases. Peritoneallacera-
tion should be repaired primarily and perforation ofbowel
requires the expertise of a general surgeon. Tominimize
postoperative ileus. the bowel and mesentery shouldbein-
spected for torsion prior to closure. Ureteral injuriescan
occur from retraction or manipulation.
Renal anomalies
can also preclude this surgical approach. Wound infection
and dehiscence are potential delayed complications.Useof
preoperative antibiotics. meticulous skin preparation.and
good surgical technique help avoid infections; properclo-
sure of each muscular layer with strong suture material
helps prevent dehiscence.

54
ThoracicSympathectomy
RobertE.Isaacs
. Indications
. Contraindications
. Advantages
. Disadvantages
. Objective
. UpperThoracicGanglionectomy
SurgicalTechnique
. LowerThoracicSympathectomy/Splanchnicectomy
SurgicalTechnique
Severaldecades ago, sympathectomy was a common neuro-
surgicalprocedure. Given significant medical and surgical
advancesthat have occurred in the interim, the indications,
andthereforethe number of sympathectomies that are per-
formedyearly, have lessened substantially. Whereas it was
recentlyconsidered a viable option in the treatment of vas-
culardiseasessuch as hypertension, Buerger's disease, inter-
mittentclaudication, and diabetic and nondiabetic ischemic
ulceration,its role in the treatment of these disorders is cur-
rentlyquestionable.! Byfar,the most common application of
upperthoracic sympathectomy is in the treatment of med-
icallyrefractorypalmarhyperhidrosis2.3-aconditioncharac-
terizedby excessive sweating of the hands. Less common
butviableindications include axillary hyperhidrosis,2 cran-
iofacialhyperhidrosis, ischemic rest pain when direct arter-
ial surgery is impractical,4 major (and perhaps minor)
causalgia,Sand shoulder-hand syndrome.s Unfortunately, it
appearsthat its effect on Raynaud's phenomenon is tran-
sient,and therefore should only be undertaken with the
knowledgethat the effect will remain short-lived.4Evenas a
treatmentfor these disorders, open sympathectomy is being
supplantedby the endoscopic approach.
Surgical sympathectomy
consists
of three
different
procedures, upper thoracic/ganglionectomy,
lower tho-
racic/splanchnicetomy,and lumbar, the first two of which
arecoveredin this chapter. Splanchnicetomy is reserved to
treatretroperitoneal pain syndromes, primarily as a result
ofpancreaticmalignancy. Other disorders, such as pain as-
sociatedwith chronic pancreatitis, have been treated with
sympatheticdenervation with less consistent, long-term
success.Lumbersympathectomy has similar indications to
upper thoracic ganglionectomy in the treatment
of the
lower extremities.
.
Indications
. Upper thoracic sympathectomy (U)
.
Palmar hyperhidrosis
.
Axillaryhyperhidrosis
.
Craniofacialhyperhidrosis
.
Ischemic rest pain (only when direct arterial surgery
is impractical)
.
Major(and perhaps minor) causalgia
.
Shoulder-hand syndrome
.
Raynaud's phenomenon (short-term treatment)
.
Lowerthoracic sympathectomy/splanchnicectomy (L)
.
Retroperitoneal pain syndromes (primarily associ-
ated with pancreatic cancer)
.
Contraindications
.
As treatment
for vascular diseases (Buerger's disease,
intermittent
claudication,
diabetic and nondiabetic
ischemic ulceration, gangrene, hypertension) in which
better medical and surgical treatments have not been
considered and exhausted (U/L)
.
Medical comorbidity (primarily pulmonary) preventing
thoracotomy (L)
421

..
422
Thoracic and Thoracolumbar Spine: Antero/Anterolateral
Approach
.
Advantages
.
Potentially better visualization
and ability
to address
complications (U/L)
.
Extrapleural approach (U)
. Requiresonly one incision (U)
.
Disadvantages
. Higher blood loss (U/L)
.
Greater postoperative pain and associated pulmonary
morbidity (U/L)
.
Need for two incisions (L)
.
Objective
Todenervatethe upper extremity (upper thoracic) or the
pancreas (lower
thoracic)
of its sympathetic
tone
. Upper Thoracic Ganglionectomy
Surgical Technique
A variety of approaches have been advocated to reach the
upper thoracic sympathetic
chain. These include dorsal
midline,6.7 dorsal paramedian,s
transthoracic,9
anterior
transthoracic,9 supraclavicular,lO and transaxillary.l0-12 Each
approach has its proponents, aswell asdrawbacks. Comfort
level with the anatomy, ability to perform the procedure bi-
laterally from a single incision, and less risk to injuring the
pleura lead many neurosurgeons to favor the posterior ap-
proach.
Anesthesia and Positioning
The patient is placed in the prone position after routine en-
dotracheal anesthesia is administered. Pressure points are
padded.An x-ray is used to confirm the location of the spin-
ous processofT2/pedicle ofB.
Routine skin prep and intra-
venousantibiotics are administered.
Incision
After
x-ray
confirmation,
a midline
incision
is made
centered about the spinous process ofT2/pedicle ofB,
ex-
tending the opening approximately four levels to expose
out the medial rib and transverse process of T3. After the
muscles are elevated in a subperiosteal fashion, a confirma-
tory x-ray should be taken prior to beginning the bone work
(Fig. 54-1).
Figure 54-1
The exposure and initial dissection is essentiallythe
same as a 13 costotransversectomy. The area shown in the circle
details
the rib and transverse process to be removed.
Exposure of the Sympathetic
Chain
A Kerrison rongeur is used to remove the transverse
process
and medial aspect of the rib ofB. Unlike the standard cos-
totransversectomy,entry intothe canaland removalofthe
pedicle are unnecessary. Aswell, there is no need to remove
the headofthe ribor itsattachments.Careistakentoavoid
injury to the underlying pleura and neurovascular struc-
tures. The T2 ganglion lays just rostral and ventral to the
transverseprocessofT3. Forthis reason,at timesitmaybe
necessary to remove part of the rib ofT2, facilitating visual-
ization of the second intercostal nerve and its contributions
to the sympathetic chain. Blunt dissection helps to freethe
ganglion from the vertebral body. When adherent to the
parietal pleura, care must be taken to avoid entry into
the chest cavity as one separates the pleura from the chest
wall (Fig.54-2).
Ganglionectomy
Once the sympathetic chain is well visualized and fullymo-
bilized, the ganglionectomy can take place. Vascular clips
are placed above and below the ganglion
and the chain is
divided.
The white
and
gray
communicating
rami are
sharply cut (Fig. 54-3).
If a bilateral
procedure
is required,
attention
is shifted to the opposite
side and the operation is
essentially repeated.

54
ThoracicSympathectomy
423
Figure 54-2
After the bone work
is completed
and the pleura has
beenbluntly dissected
off the adjacent
vertebral
bodies, the sympa-
thetic chain may be visualized.
Above one can see the horizontally
runningT2 intercostal
nerve as the more ventral sympathetic
chain de-
scendsthrough the field.
Figure54-3
Detailed anatomy showing the ganglionectomy. The
chainaboveandbelow issurgicallyclipped and ligated.
Closure
Prior to closure, the wound is irrigated. When filled with
saline, even occult pleural tears may be noted. Ifthe pleura
is violated, a catheter (no. 12 French red rubber or similar)
is placed into the defect and tunneled out a separate open-
ing. It is clamped until the wound is closed, at which point
it is opened while the patient receives positive pressure
ventilation. It should be pulled out under water seal, evacu-
ating any accumulated air and thus avoiding the need for
chest tube application.7
The wound is closed in layers, with care taken to ensure
tight fascial coverage. Asubcuticular suture or staples may
be used to close the skin. After a dressing is applied, the pa-
tient is extubated and monitored overnight in the hospital.
Whether the pleura is entered or not, postoperative chest x-
rays should be ordered in the recovery room to rule out the
existence of a pneumothorax.
.
Lower Thoracic
Sympathectomy
ISplanchnicectomy
Surgical Technique
The pancreas is felt to derive its sympathetic innervation bi-
laterally from the greater, and to less of an extent, the lesser
and perhaps least splanchnic nerves. For this reason, most
authors favor interruption of the visceral afferent projec-
tions from the pancreas by removing the ganglia from T9 to
T12and all identified splanchnic nerves.13
Anesthesia
and Positioning
The prone position is utilized after routine single-lumen en-
dotracheal anesthesia is administered. Pressure points are
padded. Routine skin prep and intravenous antibiotics are
administered.
Incision and Initial Dissection
After x-ray confirmation, a vertical incision is made 4 to 5
cm off midline centered about the eleventh rib. Sharp dis-
section and cauterization help to expose the chest wall.The
periosteum is then stripped from approximately 4 to 6 cm
of rib. A Doyen elevator helps remove the ventral perios-
teum. Care is taken to cut the eleventh rib as medial as pos-
sible to help facilitate the later aspects of the case,although
the head of the rib and its associated attachments may be
spared. (Fig.54-4).
Exposureof the Sympathetic Chain
Beginning once again as medial as possible, the pleura is
bluntly dissected offof the remaining rib, then the adjacent

424
Thoracicand Thoracolumbar Spine:Antero/Anterolateral Approach
A
iI
B
Figure 54-4
Rib removal.
(A) The process for removing
the eleventh
rib begins by
stripping
the dorsal
periosteum.
(B) This is followed
by removing
the ventral pe-
riostium
using a Doyen elevator.
(C) Finally, the rib is cut both laterally
and medially
C
using a rib cutter.
ribs,then finallythe lateral aspect ofthe vertebral bodies
(Fig.54-5). Care is taken to avoid injury to the underlying
pleura and neurovascular structures. Encountered vessels
may be coagulatedwith a bipolar electrocautery or clipped.
The lung, invested in pleura, can be retracted using a mal-
leable retractor. The sympathetic chain lies slightly ventral
to the costovertebral joints; the nerves run just anterior to
this. When adherent to the parietal pleura, care must be
taken to avoid entry into the chest cavity as one separates
these two structures.
Ganglionectomy
The sympathetic chain isvisualizedand fullymobilized,from
the diaphragm until the T9 ganglion. Vascular clips are
placed above and below the chain,which is then divided.The
white and gray communicating rami at each levelare sharply
cut. Consistently present is the greater splanchnic nerve; the
others are more variable. Regardless, the entire visualized
length of these nerves should be clipped and removed
Figure 54-5
Blunt dissection. The pleura is bluntly dissected away
from the vertebral bodiesfrom T9 through T12, exposingout the sym-
pathetic chainasit coursesover the rib heads.

54
ThoracicSympathectomy
425
(Fig.54-6). Once this is completed. attention
is shifted to the
opposite side. and the operation is essentially repeated.
Closure
Priortoclosure.the wound isirrigated. Filledwith saline.even
occultpleural tears may be noted. Ifthe pleura is violated, a
catheter(no. 12 French red rubber or similar) is placed into
the defect and tunneled out of a separate opening. It is
clampeduntil the wound isclosed,at which point it is opened
whilethe patient receives positive pressure ventilation. It
shouldbe pulled out under water seal, evacuating any accu-
mulatedairand thus avoidingthe need for chest tube applica-
tion.7l.argerpleural tears will requirechest tube placement.
Thewound is closed in layers. with care taken to ensure
tightfascialcoverage. Asubcuticular suture or staples may
beusedto close the skin. After a dressing is applied. the pa-
tientis extubated and monitored overnight in the hospital.
Whetherthe pleura is entered or not. postoperative chest x-
raysshould be ordered in the recovery room to rule out the
existenceof a pneumothorax.
References
1. Gordon A. Zechmeister
K. Collin j. The role of sympathectomy
in cur-
rent surgical practice.
Eur J Vase Surg 1994;8:129-137
2. ByrneJ.Walsh TN. Hederman
WP. Upper thoracic
sympathectomy
for
primary
palmar and axillary
hyperhidrosis:
long-term
follow up. Br J
Surg 1992;79:975-976
3. Dohn OF. Sava GM. Sympathectomy
for vascular
syndromes
and hy-
perhidrosis
ofthe
upper extremities.
Clin Neurosurg
1978;25:637-650
4.
Nicholson
ML. Dennis
MJ. Hopkinson
BR. Endoscopic
transthoracic
sympathectomy:
successful
in hyperhidrosis
but can the indications
be extended?
Ann R Coli Surg EngI1994;76:311-314
5.
Bergan JJ. Con J. Sympathectomy
for pain relief. Med Clin North Am
1968;52:147
6. Cloward RB. Upper thoracic sympathectomy:
surgical technique.
Surgery 1969;66: 1120-1126
7. Hardy RW. Bay JW. Surgery
of the sympathetic
nervous
system.
In:
Schmidek
HH. Sweet WHo eds. Operative
Neurosurgical
Techniques.
Vol2. New York: Grune & Stratton;
1988:1271-1280
Suggested Readings
ByrneJ. Walsh TN. Hederman
WP. Thoracoscopic
sympathectomy.
Endosc
Surg Allied Techno11993;1
:261-265
EllisH.Transthoracic
sympathectomy.
Br J Hosp Med 1986;35:50-51
Greenwood B. The origins of sympathectomy.
Med Hist 1967;11 :165-169
Figure 54-6
Postsympathectomy. The chain and the splanchnic
nerves are sharplycut where shown. removing the sympatheticout-
flowto the retroperitoneum.
8.
Smithwick
RH. The rationale
and technic
of sympathectomy
for the
relief of vascular
spam of the extremities.
N Engl J Med 1940;222:699
9.
Palumbo
LT.Anterior
transthoracic
approach
for upper
thoracic
sym-
pathectomy.
Arch Surg 1956;72:659
10.
Little JM. May J. A comparison
of the supraclavicular
and axillary
approaches
to upper
thoracic
sympathectomy.
Aust
N Z J Surg
1975;45:
143-146
11. Berguer R. Transaxillary sympathectomy.
Ann Vase Surg 1986;1:
155-156
12. Berguer R.Smit R.Transaxillary sympathectomy (T2 to T4) for relief
of vasospastic/sympathetic
pain of upper
extremities.
Surgery
1981 ;89:764-769
13.
Sadar ES. Cooperman
AM. Bilateral thoracic
sympathectomy-splanch-
nicetomy
in the treatment
of intractable
pain due to pancreatic
carci-
noma. Cleve Clin Q 1974;41: 185-188
GruszkiewiczJ.
Doron Y.GuilburdJN.
et al. Hyperhidrosis
and its surgical
treatment.
Acta Neurochir
(Wien) 1986;81 :128-131
Shih CJ.Wang yc. Thoracic
sympathectomy
for palmar
hyperhidrosis:
re-
port of 457 cases. Surg Neuro11978;
10:291-296

55
TransthoracicDiskectomy
RobertE.Isaacs
. Indications
. Contraindications
. Advantages
.
Disadvantages
. Objective
.
SurgicalTechnique
Thoracic disk herniations are much less prevalent than
those seen in the lumbar or cervical spine; in fact, they
account for only 0.25 to 0.5%of all spinal disk herniations.
Despite their relative rarity, patients with symptomatic tho-
racic disk herniations present with significant neurological
sequelae, most frequently related to progressive myelopa-
thy, and require aggressive treatment.
The incidence of
symptoms of myelopathy as presenting complaints is testa-
ment to the fact that these disk herniations tend to be cen-
tral or paracentral, are relatively large, and tend to deform
and compress the adjacent spinal cord. For these reasons,
the natural history of this disorder is discouraging; without
surgical intervention the majority of patients fail to regain
their previous level of function.
Thoracic disk herniations were initially approached by
dorsal laminectomy-with poor results. Outcomes were es-
peciallybad in patients with centrally located disk hernia-
tions. Even many of those with more laterally based disk
herniations failedto improve or, more significantly,deterio-
rated further. Initially, dorsolateral, and more recently,
transthoracic approaches have yielded encouraging results
with decreased neurological morbidity. Thus the history of
surgery in the thoracicspine reiterates a basic neurosurgical
tenet-whenever
possible, compressive lesions in the ner-
vous system should be removed directly.
The benefits to the use ofa thoracotomy for spine surgery
are considerable. The surgeon's view of anterior dura and
posterior longitudinal ligament is unsurpassed when com-
pared with the other routes to the thoracic spine. This fact
is only reemphasized when one takes into consideration
that the majority of pathology in the thoracic spine is ven-
tral. Ventral spinal access affords the ability to perform a
decompression
and
reconstruction
(when
required)
through a single approach, allowing for anterior stabiliza-
tion with fusion under compression. Disadvantages are the
426
Anesthesia
Approach
Positioning
Incisionand Initial Dissection
Removalof the RibHead
Diskectomy
Closure
medical complications related to the approach-persistent
pneumothorax, pulmonary contusion, pneumonia, pleural
effusion, or empyema. But for centrally located thoracicdisk
herniations, thoracotomy allows the surgeon to gain a pedi-
cle to pedicle decompression under direct visualization-a
luxury unobtainable through other approaches to the tho-
racic spine.
.
Indications
.
Centralor paracentralthoracicdisk herniationscausing
neurological symptoms (intractable radiculopathyor
progressivemyelopathy)
. Diskitis
.
Anterior release during scoliosis correction
.
Contraindications
.
Medical comorbidity such as severe cardiopulmonary
disease, acute respiratory distress syndrome (ARDS)
preventing safe access through the chest
.
Advantages
.
Controlled exposure to the anterior dura
.
Procedure of choice for correction of scoliosis
.
Ease in control of the radicular vasculature
.
Abilityto place ventral instrumentation (when indicated)

. Disadvantages
55
TransthoracicDiskectomy
427
. Increasedincidence of pulmonary complications (atelec-
tasis,pneumonia, pleural effusion, pulmonary contusion,
chylothorax, persistent
pneumothorax,
bronchopul-
monaryfistula)
. Possibleincreased incidence of medical complications as
a result of a thoracotomy (thromboembolism,
vascular
injuries)
. Increased post-procedural pain (postthoracotomy
pain
syndrome,intercostal neuralgia)
. Objective
Removalof the pathological
disk fragment through a ventral
approach
. SurgicalTechnique
Theprocedure is performed using a standard posterolateral
thoracotomy. For further detail describing the approach,
pleasesee Chapter 51.
Anesthesia
Diligencein the preoperative workup and concern for the
anestheticconsiderations of the case can significantly help
tominimizemorbidity and facilitate the procedure. Preoper-
atively,whenever possible, the patient should obtain med-
icalclearance prior to undergoing a thoracotomy. This may
includepulmonary function tests and/or a cardiac stress
test.Routinelaboratory work, including coagulation studies,
achestx-ray, and an electrocardiogram are obtained. Blood
iscross-matched in case there is a need for transfusion. Rou-
tinely,an arterial line and central venous access (frequently
withan associated Swan-Ganz catheter) are utilized to help
monitorand resuscitate the patient intraoperatively. Deep
venous thrombosis prophylaxis-sequential
compression
devices, compression
stockings,
and/or
subcutaneous
heparin-is administered along with prophylactic antibi-
otics.Corticosteroids are also given. The neuromuscular
blockingagents are allowed to wear off early in the proce-
duretofacilitateneurophysiologicalmonitoring.
Thechoice of endotracheal tube is based on the location
ofthe patient's pathology. With lesions from T2 to T8, a
double-lumen tube is placed so that the lungs may be ven-
tilatedindependently and the upper lung can be deflated to
allowfor more exposure. Below the level ofT8, a single-lu-
mentube can, at times, be utilized to avoid independent
lungventilation.
Approach
Correctlyidentifying the pathological vertebral disk space
levelis of utmost importance. This is more pertinent in the
thoracicspine given the lack of helpful identifying features
to distinguish between adjacent vertebrae (such helpful
identifying anatomy includes C2,the cervicothoracic junc-
tion, thoracolumbar junction, L5,and sacrum). Therefore,
preoperative studies must include one or more of these
landmarks; intraoperative imaging is used to reconfirm to
help localize the correct level.
The approach maybe taken fromeither the right or the left
side. The left side is typically favored by most surgeons for
access to the lower thoracic spine, given the relative ease of
mobilizing the aorta as compared with the more significant
venous structures (vena cava or azygous system) found on
the contralateral aspect ofthe bony spine.Theorientation of
the liver with respect to the spine also causes most surgeons
to favorthe left-sided approach for operations about the tho-
racolumbar junction. In contrast, given the location of the
great vessels, a right-sided posterolateral thoracotomyfacili-
tates the access to the upper thoracic spine,12 toT6.Despite
these considerations, the side of the approach canbe altered
to help address the patient's pathology.
Positioning
The patient is placed in the lateral decubitus position. Care
is taken to ensure a 90 degree orientation to the floor, al-
though some surgeons favor tilting the patient slightly pos-
terior to increase visualization during the decompression.
Regardless, it is important to maintain a mental picture of
the patient's alignment during the decompression to keep
reference to the location of the thecal sac. A beanbag is
placed under the patient; once deflated, tape is used to se-
cure the positioning. The lower leg is straightened, the up-
per leg is bent to relax the ipsilateral psoas muscle and fa-
cilitate the mobilization of this structure. An axillary roll is
placed underneath the dependant arm to decrease the rate
of brachial plexus injury. Pillows are placed between and
under the legs.Commonly,the table is flexed to increase ex-
posure by spreading the rib cage. Somatosensory evoked
potential monitoring is placed and can be used to evaluate
the integrity of the posterior column function (and there-
fore spinal cord function) during the procedure.
Incision and Initial Dissection
X-rays are taken and the location for the skin incision is
confirmed. The incision is made one to two levels above the
pathological disk space because the ribs tend to turn ros-
trally as they approach the spine. The exact location of the
incision is based on the initial intraoperative image and is
chosen to afford the surgeon a perpendicular access to the
pathology (Fig. 55-1). Once the skin is incised, the latis-
simus dorsi and serratus anterior muscles are retracted.
Subperiosteal dissection is used to expose the lateral aspect
of the rib. ADoyen elevator helps to strip the periosteum off
of the medial aspect of the rib.Arib spreader is then placed.
Two standard approaches can be used to access the ven-
tral thoracic spine, one extrapleural and one intrapleural.
The retropleural
(or extrapleural) approach takes place
within the space between the parietal pleura and the
endothoracic fascia, a fascial layer tightly adherent to the
periosteum of the rib and vertebral body. Blunt dissection is

.
428
ThoracicandThoracolumbarSpine:AnteroJAnterolateralApproach
I
.~,
\
\
Figure 55-1
Positioning and skin incision. A standard posterolateral
thoracotomy
is employed with the patient in a lateral decubitus posi-
tion. The location of the incision is based on the initial intraoperative
film but usually is one to two ribs higher than the named disk space.
used to mobilize the pleura off of the posterior chest wall
and vertebral
bodies.
This helps expose
the sympathetic
chain, radicular vasculature,
rib, and vertebral bodies them-
selves. If a totally extrapleural
approach is performed, there
is no need to place chest tube and there is decreased pul-
monary morbidity. With the extrapleural approach, asur-
geon can effectively expose up to three disk space levels.
If a trans pleural (or intrapleural)
approach
is undertaken,
the lung is retracted
with
a malleable
retractor
and the
spine is approached through the parietal pleura. Thepleura
overlyingthe spine is then flappedback,exposingtheun-
derlying structures. The "flap," based medially, is madeby
incising the pleura vertically, exposing the vertebral body
aboveand below the pathologicaldisk space(Fig.55-2).
The transpleural approach gives an increased anteroposte-
rior visualization of the offending pathology. Closurewill
then require reapproximation of the parietal pleura.
Again.anx-rayis takento confirmthe leveloftheappro-
priate vertebral body prior to proceeding with the case.
Removal of the Rib Head
The segmental vessel can be maintained when operating
on a thoracic disk as these vessels lie essentially midway
between disk spaces, or they may be taken early in the case
upon exposure. Many surgeons favor early ligation because
this tends to help minimize blood loss during the remainder
of the case. The vessels are taken on the body of the verte-
brae to maintain the arcade more distally, thereby avoiding
ischemic cord complications.
The head of the rib (2-3 em) is removed using an os-
teotome or high-speed drill. The rib head is disarticulated
Figure 55-2
Pleural flap. If a transpleural approach is under-
taken, the pleura is flapped back to expose the pathology. Here
shown isthe flap, with its basedventrally. At the end of the proce-
dure, the pleura should be reapproximated.

-
55
TransthoracicDiskectomy
429
bybeing freed from its ligamentous (costotransverse and
costovertebral) attachments
using a downgoing curette
(Fig.55-3A). Byremoving the rib. it is possible to identify
theintercostal nerve from the undersurface of the named
riband trace it back toward the neural foramen. It is this
maneuverthat helps to ascertain the location of the pedicle
aswelland allows the surgeon to gain an early understand-
ingofthe locationof the thecal sac.
The upper portion of the pedicle can be drilled and
then removed in part or completely using a Kerrison
(Fig.55-38). Onceremoved, the lateral thecal sac is identi-
fiedandcanbe visualized during the remainder of the proce-
dure.Oncethe surgeon has knowledge of the location of the
spinalcord,it then becomes safe to begin the diskectomy.
A
-~--
/--,
-
- ')
L--
/
Diskectomy
The disk is incised using a knife or the osteotome and re-
moved anteriorly away from the thecal sac. Diskectomy is
facilitated by removing a small section (-1
cm) of the
neighboring vertebral bodies (Fig.55-3C). It may be neces-
sary to widen this in the case ofvery calcifieddisks or those
that have migrated behind the vertebral body. The initial
diskectomy is performed by removingthe disk material that
clearly lies away from the ventral canal.Theremaining disk
can then be removed working from the thecal sac medially
(Fig. 55-3D). Once a cavity is created (by performing the
initial diskectomy and adjacent bone removal),the remain-
ing disk can be reduced into this cavity,thereby all force is
B
c
r"
~.
D
Figure55-3
The operation.
(A) Adownpushing
curette is used to free the rib head from its attachments
to the vertebral body so the disk space
canbebetter visualized. (B) Ahigh-speed drill is used to remove the upper portion of the pedicle. AKerrison is used to complete this, exposing the
lateralaspect of the thecal sac. (C) Area of the initial diskectomy and adjacent bony removal. Into this defect the remainder of the disk can be evacu-
ated.(D)Adownpushing curette is used to push the remaining disk that is adjacent to the spinal cord toward the defect. All pressure is away from
thecord.

430
ThoracicandThoracolumbarSpine:Antero/Anterolateral Approach
directed away from the spine. Tominimize epidural bleed-
ing, the posterior longitudinal ligament is kept intact
throughout the diskectomy. Once complete, it may be cau-
terized then removed as a last step. A Woodsen or no. 4
Penfield can be used to ensure that no sequestered frag-
ments lay hidden superior and inferior to the visualized
area. The inspection should be undertaken from pedicle to
pedicle, insuring adequate decompression
of the spinal
canal and the complete removal of the offending pathology.
If the contralateral pedicle cannot be felt, it is possible to
take an anteroposterior film to confirm the extent of the de-
compression.
Although not common, it is possible to destabilize a pa-
tient through this procedure. In the case of extensive bony
removal (secondary
to a large sequestered
disk), the
patient may require fusion. Most authors do not believe
that this is required for the majority of thoracic disk
herniations.
Closure
When incised, the diaphragm is reattached at its lateralmar-
gin, with the crura being sewn directly to the anterior longi-
tudinalligament.
Any violations
in the peritoneum
should
be closed primarily.
When
entered,
the parietal
pleura is
closed as well overlying the diskectomy. If a retropleural ex-
posure
was performed,
the wound
should be filled with
saline to confirm that no occult pleural lacerationtookplace.
When the pleura is entered,
a chest tube is placed and tun-
neled out through
a separate
incision. Once the wound is
fully closed, the chest tube is placed onto low wall suction-
ing. The lung is reinflated under direct visualization.
The intercostal musculature is closed using a running suture.
The remainder of the tissue layers are closed with interrupted
sutures. Staples or a running suture are used to close the skin.
A sterile dressing is applied. Whether
or not the pleura isen-
tered, a chest x-ray must be performed in the recoveryroom.

56
TransthoracicVertebrectomy
Robert E. Isaacs
. Indications
. Contraindications
. Advantages
. Disadvantages
. Objective
. SurgicalTechnique
Surgeryfor the treatment
of pathology to the thoracic
spinewas classically fraught with complications. Compres-
sivelesions were usually anteriorly
based. When they
wereaddressedbydorsallaminectomyfordecompression,
theresults were notoriously poor. An unfortunately large
numberof patients failed to improve or, more significantly,
deteriorated further.
Dorsolateral,
and more recently,
transthoracicapproaches, have yielded encouraging results
withdecreased neurological morbidity. Thus the history of
surgeryin the thoracic spine reiterates a basic neurosurgical
tenet-whenever possible, compressive lesions in the ner-
voussystem should be removed directly.
Thebenefits of a thoracotomy for spine surgery are con-
siderable.The surgeon's view of anterior dura and poste-
riorlongitudinal ligament is unsurpassed when compared
withthe other routes to the thoracic spine. Ventral spinal
accessaffords the ability to perform a multilevel decom-
pressionand reconstruction
(when required) through a
singleapproach, allowing for anterior stabilization with
fusionunder compression. Transthoracic approaches were
initiallydeveloped as treatment
for Pott's disease, first
describedin 1956 as a treatment for spinal tuberculosis.!
Theindications for transthoracic
corpectomy have been
broadened to
include
surgical
treatment
of spinal
deformities,other forms of osteomyelitis, traumatic burst
fracture,and tumors. The disadvantages are the medical
complications related to the approach-persistent
pneu-
mothorax,pulmonary contusion, pneumonia, pleural effu-
sion,or empyema. Furthermore, because the contralateral
pedicleand posterior elements are not well visualized by
this approach, a second operation is needed to address
pathologyof the posterior element and/or for the place-
mentof posterior instrumentation.
But for the majority of
thoracicspine pathology that lies anterior to the spinal
cord,thoracotomy allows the surgeon to gain a pedicle
Anesthesia
Approach
Positioning
Incision and Initial Dissection
Removal of the Rib Head
Diskectomies and Corpectomy
Closure
to pedicle decompression
under direct visualization-a
luxury unobtainable through other approaches to the tho-
racic spine.
.
Indications
.
Primary or metastatic vertebral neoplasm
.
Unstable thoracic fracture
.
Osteomyelitis or diskitis
.
Spinal deformities
.
Sequestered thoracic disk herniation causing neurologi-
cal symptoms (myelopathy, radiculomyelopathy, refrac-
tory radiculopathy)
.
Contraindications
.
Medical comorbidity such as severe cardiopulmonary
diseaseand acute respiratorydistresssyndrome(ARDS)
preventing safe access through the chest
.
Limited life expectancy
.
Advantages
. Controlledexposuretothe anteriordura
.
Procedureofchoiceforcorrectionofscoliosis
.
Easein controlofthe radicularvasculature
. Abilityto performcorpectomyand placeventral instru-
mentationfroma singleapproach
431

432
Thoracicand Thoracolumbar Spine:Antero/Anterolateral Approach
. Disadvantages
.
Increased incidence of pulmonary complications (atelec-
tasis. pneumonia, pleural effusion, "postthoracotomy"
pain syndromes. chylothorax. persistent pneumothorax
bronchopulmonary. fistula)
.
Possibleincreased incidence of medical complications as
a result of a thoracotomy (thromboembolism. vascular
injuries)
. Asecond operation may be needed to address posterior
element pathology.
. Objective
Directanterior approach to the spine for removal of patho-
logicalventral thoracic vertebral pathology
.
SurgicalTechnique
The procedure is performed using a standard posterolateral
thoracotomy. The surgical approach is described in detail
elsewhere (see Chapter 51).
Anesthesia
Diligence in the preoperative workup and concern for the
anesthetic considerations of the case can significantly help
to minimize morbidity and facilitate the procedure. Preop-
eratively. whenever possible. the patient should obtain
medical clearance prior to undergoing a thoracotomy. This
mayinclude either or both pulmonary function tests and a
cardiacstress test. Routine laboratory work, including coag-
ulation studies, a chest x-ray. and an electrocardiogram are
obtained. Bloodis cross-matched in case there is a need for
transfusion. Routinely, an arterial line and central venous
access(frequently with an associated Swan-Ganz catheter)
are utilized to help monitor and resuscitate the patient
intraoperatively. Deep venous thrombosis prophylaxis-
sequential compression devices, compression stockings.
and/or subcutaneous heparin-is
administered along with
prophylactic antibiotics. Corticosteroids are also given. The
neuromuscular blocking agents are allowed to wear off
early in the procedure to facilitate neurophysiological moni-
toring.
Approach
Correctly identifying the pathologicalvertebrae is of utmost
importance. This is more pertinent in the thoracic spine
given the lack of helpful identifying features to distinguish
between
adjacent
vertebrae (such helpful
identifying
anatomy includes C2,the cervicothoracic junction. thora-
columbar junction, L5,and sacrum). Therefore,preoperative
studies must include one or more of these landmarks; intra-
operative imaging is used to reconfirm and help to localize
the correct level.
Theapproachmaybe takenfrom either the rightorleft
side. The left side is typically favored by most surgeonsfor
access to the lower thoracic spine. given the relative easeof
mobilizing the aorta as compared with the more significant
venous structures (vena cava or azygous system) foundon
the contralateral aspect of the bony spine. The orientation
of the liver with respect to the spine also causes most sur-
geons to favor the left-sided approach for operations about
the thoracolumbar junction. In contrast, given the location
of the great vessels. a right-sided posterolateral thoraco-
tomy facilitates access to the upper thoracic spine.12 to16.
Despite these considerations. the side of the approach can
be altered to help address the patient's pathology.
Positioning
The patient is placed in the lateral decubitus position
(Fig. 56-1). Care is taken to ensure a 90 degree orientation
to the floor. although some surgeons favor tilting the pa-
tient slightly posterior to increase visualization during the
decompression. Regardless. it is important to maintain a
mental
picture of the patient's
alignment
during the
decompression to keep reference to the location ofthe the-
cal sac. A beanbag is placed under the patient; when
deflated. tape is used to secure the positioning. The lower
leg is straightened. and the upper leg is bent to relax the
/
J
Figure 56-1
Positioning. Astandard
posterolateral
thoracotomy
is
employed with the patient in a lateral decubitus position. The location
of the incision is based on the initial intraoperative
film, but usually is
one to two ribs higher than the rib ofthe pathological vertebra.

56
Transthoracic Vertebrectomy
433
ipsilateral psoas muscle and facilitate the mobilization of
thisstructure. Anaxillary roll is placed underneath the de-
pendant arm to decrease the rate of brachial plexus injury.
Pillowsare placed between and under the legs. Commonly,
thetable is flexed to increase exposure by spreading the rib
cage.Somatosensory evoked potential monitoring is placed
andcan be used to evaluate the integrity of the posterior
columnfunction (and therefore spinal cord function) during
theprocedure.
Incisionand Initial Dissection
X-raysare taken and the location for the skin incision is
confirmed.Especially when an anterior reconstruction is
goingto be performed, a C-arm should be positioned and
adequateintraoperative films must be confirmed prior to
preppingthe patient. The surgical prep should include the
entirearea from the axilla to the ipsilateral iliaccrest.
Theincisionis made along the rib one to two levels above
thepathologicalvertebrae (Fig.56-2) because the ribs tend
toturn rostrally as they approach the spine. The exact loca-
tionof the incision is based on the initial intraoperative
imageandis chosento affordthe surgeona perpendicular
accessto the pathology.Afterthe skinis incised,the latis-
simusdorsi and serratus anterior muscles are retracted.
Subperiostealdissection is used to expose the lateral aspect
ofthe rib.ADoyenelevator helps to strip the periosteum off
ofthe medial aspect of the rib. The rib is removed and the
ribspreader is placed.
Twostandard approaches can be used to access the ven-
tralthoracic spine, one extrapleural and one intrapleural.
Theretropleural(or extrapleural) approach takes place within
thespacebetween the parietal pleura and the endothoracic
fascia,a fasciallayertightly adherent to the periosteum of the
ribandvertebral body. Blunt dissection is used to mobilize
thepleuraoff of the posterior chest wall and vertebral bod-
ies.Thishelps expose the sympathetic chain, radicular vas-
culature,rib, and vertebral bodies themselves. If a totally
extrapleural approach is performed, there is no need to
placea chest tube and there is decreased pulmonary mor-
bidity.With the extrapleural approach, a surgeon can effec-
tivelyexpose up to three disk space levels.
Figure56-2
Skinincision, lateral view,again showing the incision
foraT12corpectomy.Notethat the table isflexedto increasethe ex-
posureto the pathologicalvertebrae.
\
Figure 56-3
Pleural flap. If a transpleural
approach is undertaken.
the pleura is flapped back to expose the pathology. Here shown is the
flap, which is based medially. At the end of the procedure. the pleura
can be reapproximated.
Ifa transpleural (or intrapleural) approach is undertaken,
the lung is retracted with a malleable retractor and the
spine is approached through the parietal pleura. The pleura
overlying the spine is then flapped back, exposing the
underlying structures. The "flap," based medially, is made
by incising the pleura vertically, exposing the vertebral
body above and below the pathological disc space (Fig.
56-3). The transpleural approach gives an increased antero-
posterior visualization of the offending pathology. Closure
will then require reapproximation of the parietal pleura.
Again.an x-ray is taken to confirm the level of the appro-
priate vertebral body prior to proceeding with the case.
Removal of the Rib Head
The segmental vessels are taken early in the case upon ex-
posure. Many surgeons favor their early ligation because
this tends to help minimize blood loss during the remainder
of the procedure. The vessels are taken on the body of the
vertebrae to maintain the arcade more distally, thereby
avoiding ischemic cord complications. The vessels should
be taken at the level of the pathology, and the adjacent
levels.
The head ofthe rib (2-3 cm) is removed at the levelof the
pathological vertebrae using an osteotome or high-speed
drill. The rib head is disarticulated by being freed from its
ligamentous (costotransverse and costovertebral) attach-
ments using a downgoing curette (Fig.56-4A). Byremoving
the rib, it is possible to identify the intercostal nerve from
the undersurface of the named rib and trace it back toward
the neural foramen. It is this maneuver that helps to ascer-
tain the location of the pedicle as well and allows the sur-
geon to gain an early understanding of the location of the
thecal sac. Depending upon the need for and type of ante-
rior plating system being utilized, the same process is re-
peated for the rib at the level below and/or above this level.
The upper portion of the pedicle at the level of the
pathology can be drilled and then removed using a Kerrison

434
Thoracicand Thoracolumbar Spine:Antero/Anterolateral Approach
A
~
U
~
d
B
C
Lff
L3
D
Figure 56-4
The operation.
(A) Adownpushing
curette is used to free the rib
head from its attachments
to the vertebral body so the disk space directly me-
dial to the rib can be better visualized. This is performed
over the pathological
vertebrae and perhaps at adjacent levels. (8) A high-speed drill is used to remove
the upper portion of the pedicle. A Kerrison is used to complete
this, exposing
the lateral aspect of the thecal sac. (e) Area of the initial diskectomies above and
below the pathological
vertebrae. (D) Area of the initial bony removal. Into this
defect the remainder
of the pathological
vertebrae
can be evacuated.
(E) A
downpushing
curette is used to push the remaining bone that is adjacent to the
E
,
/1
spinalcordtowardthedefect.Allpressureisdirectedawayfromthecord.
rongeur (Fig.56-48). When removed, the lateral thecal sac
is identified and can be visualized during the remainder of
the procedure. After the surgeon has knowledge of the loca-
tion of the spinal cord, it then becomes safe to begin the
diskectomies.
Diskectomies and Corpectomy
The disks surrounding the pathological vertebrae are in-
cised using a knife or the osteotome and removed anteriorly
away from the thecal sac using pituitary rongeurs. The

56
TransthoracicVertebrectomy
435
initial diskectomy is performed
by removing the disk
material that clearly lies away from the ventral canal
(Fig.56-4C).Ahigh-speed drill (or osteotome) is used to re-
movethe majority of the anterior aspect of the vertebral
bodybetween the emptied disk spaces. This helps to create
acavityanterior to and surrounding the area of neurological
compression(Fig.56-4D). It is common to leave intact the
anterior longitudinal ligament as well as the ventral and
deepcortexto help securethe bonegraft in placeafter the
completionof the procedure. Amore radical decompression
cantake place, especially in the case of tumor, but for the
majorityof cases this maneuver helps to create a barrier
to prevent injury to the adjacent vascular and visceral
structures.
Theremaining disk and the posterior cortex can be re-
movedby working from the thecal sac medially and ven-
trally.After a cavity is created (by performing the initial
diskectomiesand intervening bony removal), the remaining
diskand bone can be reduced into this cavity, thereby di-
rectingall force away from the spine (Fig. 56-4E). Tomini-
mizeepiduralbleeding,the posteriorlongitudinalligament
iskeptintact throughout the corpectomy. When complete,
itmaybe cauterized, then removed as a last step. AWood-
senor no. 4 Penfield can be used to ensure that no se-
questeredfragments lay hidden superior and inferior to the
visualizedarea. The inspection should be undertaken from
pedicleto pedicle, insuring adequate decompression of the
Reference
1. Hodgson AR.Stock FE. Anterior
spinal fusion. A preliminary
commu-
nication on the radical treatment
of Pott's disease
and Pott's paraple-
gia. BrJ Surg 1956:44:266
spinal canal and the complete removal of the offending
pathology. If the contralateral pedicle cannot be felt, it is
possible to take an anteroposterior film to confirm the ex-
tent of the decompression.
Fora discussionofthe reconstruction,please see Chapter 57.
Closure
When incised for operations near the thoracolumbar junc-
tion, the diaphragm is reattached at its lateral margin, with
the crura being sewn directly to the anterior longitudinal
ligament. Any violations in the peritoneum should be
closed primarily. When entered, the parietal pleura is
closed as well overlying the operative site. Ifa retropleural
exposure was performed, the wound should be filledwith
saline to confirm that no occult pleural laceration took
place. When the pleura is entered, a chest tube is placed
and tunneled out through a separate incision. After the
wound is fully closed, the chest tube is placed onto lowwall
suctioning. The lung is reinflated under direct visualization.
The intercostal musculature is closed using a running su-
ture. The remaining tissue layers are closed with inter-
rupted sutures. Staples or a running suture are used to close
the skin. A sterile dressing is applied. Whether or not the
pleura is entered, a chest x-ray must be performed in the
recovery room.