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Chapter 19 Anatomy of the Anterior Cervicothoracic Spine 343
FIG. 19.9 Operative exposure. A chest spreader can then be inserted and
opened after rib resection. (From Le HN, Kim DH. Anterolateral transthoracic
approaches to the cervicothoracic junction [transaxillary approach,
transpleural transthoracic third rib resection approach]. In: Kim DH, ed.
Surgical Anatomy and Techniques to the Spine. Philadelphia: Elsevier; 2006.)
FIG. 19.10 Appropriate intercostal arteries and veins are dissected, ligated,
and cut. (From Le HN, Kim DH. Anterolateral transthoracic approaches to the
cervicothoracic junction [transaxillary approach, transpleural transthoracic
third rib resection approach]. In: Kim DH, ed. Surgical Anatomy and
Techniques to the Spine. Philadelphia: Elsevier; 2006.)
Thoracotomy (Anterior) Approach to the Thoracic Spine
e transthoracic approach oers extensile exposure of the
anterior vertebral bodies from T6 to T12.4 e benets of this
approach include excellent access to the anterior column and
less risk of direct injury to the neural elements. Indications for
this approach include treatment of vertebral osteomyelitis,
resection of the vertebral body for tumors and trauma, deformity correction, and decompression of the anterior thoracic
spine. Despite this, the transthoracic approach is rarely used
secondary to the advent of posterior-based approaches that
allow the surgeon to use the same procedures with less morbidity and risk.
e patient is intubated by anesthesia using a double-lumen
endotracheal tube with lung isolation.5 is will allow for
selective lung deation based on the approach side. e patient
is then placed in the lateral decubitus position with the head
in neutral position and an axillary roll or pad placed underneath the downside axilla to protect the brachial plexus. e
arms are slightly abducted and the elbows slightly exed. e
downside leg is slightly exed at the hip and the knee;
the upside leg is slightly extended and adducted to allow for
so tissue tension, which aids in opening the intercostal space.
All bony prominences must be well padded. e patient is
secured in the lateral decubitus position via a beanbag or
padded bolsters (Fig. 19.11A).
Although the approach can be made from the le or right
side, the right side is preferred if the approach is to be made
above T10, as it avoids manipulation of the aorta. If the
approach is for access from T10 and caudad, a le-sided
approach is preferred since the liver elevates the diaphragm
on the right side in this region.
Localization of the operative level is then performed with
the aid of uoroscopy and palpation. e rib to be resected
should correspond to two levels above the operative vertebral
body level given the oblique nature of the rib. Once this is
conrmed, the rib is marked from the posterior angle of the
rib to the anterior margin.
e skin and subcutaneous tissues are incised with a No.
10 blade scalpel (Fig. 19.11B). Further dissection is carried
out with Bovie electrocautery. e latissimus dorsi is identied and incised in line with the skin in an incision over the
course of the rib. Aer completing dissection through the
latissimus dorsi, the posterior margin of the serratus anterior
is encountered and incised in a similar fashion. At this point,
the rib should be visible. Subperiosteal dissection is then
performed, skeletonizing the supercial surface of the rib
without violating the inferior margin since this is where the
neurovascular bundle runs. e intercostal muscles are then
bluntly released from the superior and inferior margins of
the rib using an Alexander Farabeuf periosteotome. Tissue
attachments to the undersurface of the rib are then carefully
released in a subperiosteal fashion without violating the parietal pleura using a Doyen dissector. e rib is then cut with a
rib cutter at the costotransverse junction posteriorly and the
costal margin anteriorly. Sharp bony edges at the margins of
resection are smoothed with a bone rasp. Bony bleeding is
controlled with bone wax. e resected rib can be saved and
used for bone gra.
Following rib resection, the appropriate lung corresponding to the operative side is selectively deated. e pleural
cavity is then entered with Metzenbaum scissors. Rib spreaders can be placed at right angles to aid in visualization. A
malleable retractor padded with moist lap sponges can be used
to further retract and protect the deated lung. One of the
major complications associated with this approach is microatelectasis. In order to help prevent this, the lung can be
periodically reinated by the anesthesiologist.
SECTION
III
344 SURGICAL ANATOMY AND APPROACHES
B
A
FIG. 19.11 (A) The patient is placed in the lateral decubitus position. The
arms are abducted and elbows are slightly exed in a position of comfort,
using blankets or pillows to hold the position. (B) The thoracotomy incision
is centered over the rib to be resected. The incision is drawn from the
posterior angle of the corresponding rib and following its curvature
anteriorly. Typically, the numbered rib that is resected is considered to be
two levels above the expected working level.
e parietal pleura is incised longitudinally over the pertinent disc space with atraumatic pickups and Metzenbaum
scissors. e parietal pleura is retracted laterally. Underlying
segmental vessels that interfere with access are carefully dissected and ligated with several vascular clips or 2-0 silk ties.
Ligation should be performed away from the aorta in order
to minimize the risk of loosening of the clips or ties. Further
cephalad or caudad exposure is gained by further longitudinal
release of the parietal pleura and ligation of segmental vessels.
It is important not to tie o more segmental vessels than
necessary, as blood supply to the spinal cord from these vessels
is variable and may result in inadvertent cord ischemia. In an
animal model, it has been shown that ligation of bilateral segmental arteries at 4 or greater consecutive levels can produce
ischemic cord dysfunction.
6
Upon completion of the procedure, the parietal pleura
is repaired and the lung is reinated. A chest tube is then
placed through the ninth intercostal space. e ribs are then
reapproximated using a rib approximator and the interval is
secured in place with heavy nonabsorbable suture. Routine
subcutaneous and skin closure is then performed and a sterile
dressing is placed.
Endoscopic Anterior Approach to the Thoracic Spine
e benets of an endoscopic approach to the anterior thoracic
spine include reduced postoperative pain levels, hastened
recovery, and minimization of common complications associated with open thoracotomy approaches.
this approach are the same as those of an open thoracotomy
approach: traumatic, degenerative, infectious, and neoplastic
etiologies requiring access to the anterior vertebral body and
disc space. Contraindications to the endoscopic approach
include patients with cardiopulmonary insuciency, acute
posttraumatic respiratory failure, or coagulopathy. A relative
contraindication is a patient with previous surgical interventions or infectious diseases of the lung, as the patient may have
excessive adhesions.
9
For this approach, equipment includes a 30-degree endoscope connected to a xenon light source and high-denition
camera. Additionally, specially made instrumentation for so
tissue handling, disc space preparation, and bone resection are
required. Consideration should be given to performing this
procedure in conjunction with a thoracic surgeon. At a bare
minimum, a thoracic surgeon should be on standby to assist
should a complication arise or the need to convert to an open
procedure occurs.
e patient is intubated with a double-lumen endotracheal
tube to allow for selective lung deation. e patient is positioned in the lateral decubitus position. All bony prominences
are padded. An axillary roll is placed under the downside
axilla. e patient is secured with a beanbag or bolsters. e
patient should be secured well to the table since table rotation
of up to 15 degrees can be helpful for visualization intraoperatively. e table should be exed to open the intercostal spaces.
e level of interest is marked on the lateral thoracic wall
utilizing a lateral uoroscopic image (in reference to the
patient’s body). ere are several described working portal
congurations.10 Traditionally, two to three working portals
and two additional portals are used. e working portal is
marked directly above the lesion in line with the posterior
axillary line. e portal for the endoscope is marked cranial
to the working portal approximately 2 intercostal spaces in
line with the midaxillary line. e portal sites for suction and
retraction are placed anterior to these portals9 (Fig. 19.12).
e ipsilateral lung is deated and a 1-inch oblique incision
is made over the site of the superior endoscope portal. is
portal hole is always created rst, as it minimizes risk to the
liver, diaphragm, and spleen. e approach is made using a
minithoracotomy technique and the chest cavity is entered
with a blunt clamp or thoracoscopic introducer. Entry should
be made on the superior portion of the rib in order to avoid
the neurovascular bundle on the undersurface of the rib.
A 10-mm, 30-degree rigid scope is inserted through a
10-mm trocar at this portal site. e remaining portals are
7,8
e indications for
Chapter 19 Anatomy of the Anterior Cervicothoracic Spine 345
A
Post-
axillary line
axillary
line
Midaxillary
line
12
11
10
1
2
3
4
5
6
7
8
9
Anterior
axillary line
B
Anterior
Working
trocar
FIG. 19.12 (A) Diagram of trocar positions for T7–T8 pathology. (B) Actual trocar positions.
placed under direct thoracoscopic visualization. At this point,
the patient can be rotated up to 15 degrees anteriorly and
placed in the Trendelenberg position for work in the lower
thoracic spine or reverse Trendelenberg for work in the upper
thoracic spine. is allows the lung to fall away from the
surgical eld.
Diagnostic thoracoscopy is performed and the target level
is identied. e ribs can be counted internally by a blunt
palpation with a grasping instrument to conrm the appropriate surgical level. Once the appropriate level is identied, a
20-gauge needle or Kirschner wire (K-wire) is placed percutaneously into the disc space and conrmed with a uoroscopic
image.
With the appropriate surgical level conrmed, the parietal
pleura over this level is cut over the rib head with cautery. e
free edge of the pleura is then grasped and released cephalad
and caudad with a hook dissector to expose the operative
level(s). If access to the vertebral body is necessary, the segmental vessels need to be clipped and ligated.
If vertebral body work is necessary, the rib head is exposed
and the costovertebral ligaments are released. e rib is then
cut 2 to 3 cm from its attachment to the spine using a burr or
Kerrison rongeur and the rib head is removed. Removal of the
rib head allows for clear visualization of the disc, pedicle, and
posterior vertebral margin. Resection of the superior vertebral
body and pedicle allows for exposure of the exiting nerve root
and spinal canal.
At the end of the procedure, hemostasis should be achieved.
Tears involving the visceral pleura should be repaired. A chest
tube is placed through the inferiormost portal, secured with
2-0 silk ties to the skin, and placed on a water seal. e lung
is reinated under direct visualization and a radiograph is
obtained to ensure full lung reexpansion. e fascia and skin
of each portal is closed in a layered fashion.
Postoperatively, serial chest radiographs are obtained until
it is felt that they can be safely discontinued. e chest tube
can be discontinued once output is less than 150 mL over a
24-hour period and no air leak is present.
Postaxillary line
Other trocars
Working
trocar
Midaxillary line
Anterior Anatomy of the Thoracolumbar Junction
e thoracolumbar junction spans from T10 to L2. It is the
transition zone between the rigid kyphotic thoracic spine
and the mobile lumbar spine. Because of this transition, the
thoracolumbar spine is predisposed to a high proportion of
trauma.
11
Across the thoracolumbar junction, the aorta lies to the le
of the midline; the azygos vein, splanchnic nerves, and thoracic duct lie to the right of midline. In the thoracolumbar
spine, the segmental arteries run horizontally from the aorta
toward their respective vertebral body.
e diaphragm is the dome-shaped structure of muscle
and brous tissues that separates the thoracic cavity from
the abdomen. e diaphragm is made up of two main parts:
the clover-shaped central tendon and a peripheral muscular
portion that attaches to the chest wall. e sternal portion of
the diaphragm is made up of two small muscular segments that
attach to the posterior aspect of the xiphoid process. e costal
portion of the diaphragm is made up of several wide muscle
segments whose origins are found on the internal surface of
the inferior six ribs and costal cartilages. e lumbar portion
of the diaphragm attaches to the spine at L1 through the le
and right crura, which blend with the anterior longitudinal
ligament. Additional spine attachments come from the medial
and lateral arcuate ligaments. e medial arcuate ligaments
arise from the crura and bridge the psoas muscle, inserting onto the transverse processes of L1. e lateral arcuate
ligament arises from the L1 transverse process, bridges the
quadratus lumborum, and attaches to the twelh rib.
Anterior Approach to the Thoracolumbar Spine
e indications for anterior approach to the thoracolumbar
spine include traumatic, infectious, and malignant etiologies
between T10 and L2. Additionally, this approach can be employed
for deformity correction as well as to treat pseudoarthrosis.
Similar to thoracotomy approaches, a double-lumen endotracheal tube should be used to allow for selective lung
SECTION
III
346 SURGICAL ANATOMY AND APPROACHES
AB
FIG. 19.13 Left-sided lateral approach positioning. (From Thongtrangan I, Le HN, Park J, Kim DH.
Thoracolumbar and lumbar spines. In: Kim DH, ed. Surgical Anatomy and Techniques to the Spine. Philadelphia:
Elsevier; 2006.)
deation. A nasogastric tube should also be in place. e
patient is positioned in the lateral decubitus position with the
approach side up. A le-side approach oers the advantage of
avoiding the need to mobilize the thin-walled vena cava as
well as risking a view obscured by the liver. If the vena cava is
injured, it can bleed profusely and can be very dicult to
repair. Sometimes, however, a right-sided approach is necessary as dictated by the surgical pathology, such as in the case
of treating the apex of a scoliotic curve.
12
Aer placing the patient in the lateral decubitus position
with the operative approach side up, the patient can be secured
with a beanbag or bolsters. All bony prominences about the
lower extremities should be padded. An axillary roll is placed.
e down leg is straightened; the top leg is exed and slightly
externally rotated to help relax the psoas muscle. Pillows can
be placed between the legs to aid in positioning. e arms are
abducted and slightly exed at the elbow. e upside arm can
be supported by an arm holder, pillows, or blankets. e
patient is further secured to the table by placing tape over the
hip and shoulder or upper chest. Care should be taken to avoid
placing the tape directly over the breast and nipple. Fluoroscopy is then used to mark the operative levels and incision.
Typically, the ninth, tenth, eleventh, or twelh rib is selected,
depending on the exposure required. e skin incision is
marked from the posterior angle of the corresponding rib
anteriorly along its course and ending distally at a level just
lateral to the pubic symphysis. e length of the incision can
be altered depending on the exposure necessary (Fig. 19.13).
Standard sterile prep and drape is performed. A No. 10
blade scalpel is used to make the skin incision over the aforementioned distribution. Subcutaneous dissection is performed
with Bovie electrocautery. e latissimus dorsi and external
oblique are split with cautery in a layered fashion. e rib is
supercially exposed posteriorly from the costotransverse
junction anteriorly to the costal margin. Next, the rib is dissected in a subperiosteal manner. When working on the
undersurface of the rib, a Doyen can be helpful. Care should
be taken to avoid injuring the underlying neurovascular
bundle and parietal pleura.
FIG. 19.14 A rib cutter is used to cut the tenth rib to expose the pleura
underneath. (From Thongtrangan I, Le HN, Park J, Kim DH. Thoracolumbar
and lumbar spines. In: Kim DH, ed. Surgical Anatomy and Techniques to the
Spine. Philadelphia: Elsevier; 2006.)
e rib is cut anteriorly at the costal margin and posteriorly
at the costotransverse junction. e resected rib can be saved
and used for bone gra (Fig. 19.14). Bleeding from the cut
edges is controlled with bone wax.
Aer rib resection, the lung is selectively deated on the
approach side. e pleura is identied and protected by splitting the undersurface of the costal cartilage anteriorly (Fig.
19.15). e retroperitoneal space is entered through the split
costal cartilage (Fig. 19.16). If the twelh rib is being resected,
the diaphragm attaches superiorly and the transverse abdominis attaches inferiorly. e diaphragm can be retracted superiorly and the transverse abdominis inferiorly, allowing
entrance into the retroperitoneum. e peritoneum is bluntly
swept o the diaphragm and abdominal muscles (Fig. 19.17).
If necessary for exposure, the external oblique, internal
oblique, and transverse abdominis muscles are incised.
With the rib resected and the peritoneum safely swept
away, a rib retractor is placed. A malleable retractor covered
with a moist lap sponge is then placed to further protect the
FIG. 19.15 The costal cartilage is split and serves as a landmark for closure.
Careful dissection underneath the split cartilage will expose the peritoneal
fat, which will lead to the retroperitoneal space. (From Thongtrangan I, Le
HN, Park J, Kim DH. Thoracolumbar and lumbar spines. In: Kim DH, ed.
Surgical Anatomy and Techniques to the Spine. Philadelphia: Elsevier; 2006.)
Chapter 19 Anatomy of the Anterior Cervicothoracic Spine 347
SECTION
III
FIG. 19.18 A rib spreader can be used to provide retraction for entry into
chest cavity. The lung is further protected with a malleable retractor
shielded with a sponge.
FIG. 19.16 The split costal cartilage is tagged temporarily. The
retroperitoneal fat is identied. (From Thongtrangan I, Le HN, Park J, Kim DH.
Thoracolumbar and lumbar spines. In: Kim DH, ed. Surgical Anatomy and
Techniques to the Spine. Philadelphia: Elsevier; 2006.)
FIG. 19.17 The retroperitoneal space is entered by pushing the peritoneal
fat along with the peritoneal content toward the midline. (From
Thongtrangan I, Le HN, Park J, Kim DH. Thoracolumbar and lumbar spines.
In: Kim DH, ed. Surgical Anatomy and Techniques to the Spine. Philadelphia:
Elsevier; 2006.)
FIG. 19.19 The diaphragm is carefully cut peripherally. (From Thongtrangan
I, Le HN, Park J, Kim DH. Thoracolumbar and lumbar spines. In: Kim DH, ed.
Surgical Anatomy and Techniques to the Spine. Philadelphia: Elsevier; 2006.)
lung. A second retractor placed perpendicular to the rst
retractor can be placed for improved visualization, if necessary
(Fig. 19.18).
e thoracoabdominal cavity is entered and the perito-
neum is carefully swept o the psoas and undersurface of the
diaphragm. e diaphragm, which should be clearly delineated
at this point, is incised circumferentially to release it (Fig.
19.19). A cu of muscle 1 cm in size should be le and tagged
for reapproximation at the end of the case (Fig. 19.20). e
crus can be taken down from its attachment at L1 if access to
T12 and L1 vertebral bodies is necessary.
For access to the thoracic spine, the parietal pleura is
incised, exposing the vertebral body. e intercostal vessels
are tied and ligated in order to mobilize the major blood
vessels to allow access to the vertebral body of interest. ey
348 SURGICAL ANATOMY AND APPROACHES
Semispinalis
Spinalis thoracis
B
Serratus
A
Intermediate
TrapeziusRhomboid
layer
Superficial
layer
FIG. 19.20 Temporary tagged sutures are used while cutting the
diaphragm, which will serve as a landmark for closure. (From Thongtrangan
I, Le HN, Park J, Kim DH. Thoracolumbar and lumbar spines. In: Kim DH, ed.
Surgical Anatomy and Techniques to the Spine. Philadelphia: Elsevier; 2006.)
should be tied and ligated greater than 1 cm from their respective foramen. Care should be taken not to injure the sympathetic plexus, which is in close proximity to the intercostal
vessels. If mobilization of the psoas muscle is required in the
lumbar spine for exposure, it should be done subperiosteally
to avoid injuring the lumbar plexus.
A layered closure for this approach should be performed.
e previously tagged diaphragm attachments are repaired
with nonabsorbable heavy suture. e parietal pleura is
repaired, if possible. e abdominal muscles are repaired in a
layered fashion. Lung reexpansion is performed. A chest tube
can be placed, if necessary. Care should be taken to ensure that
the junction of the diaphragm and abdominal musculature is
securely reapproximated to prevent hernia formation.
Posterior Anatomy of the Thoracic Spine
e posterior thoracic spine is covered by a supercial, intermediate, and deep muscle layer (Fig. 19.21). e supercial
layer consists of the trapezius and latissimus dorsi muscles.
Deep to these muscles, but still considered part of the supercial layer, are the rhomboid major and minor muscles. All of
the supercial muscles are innervated by peripheral nerves.
e intermediate layer is comprised of the serratus posterior
inferior and superior muscles. ese muscles are innervated
by the anterior rami of the thoracic nerves. Deepest of all, the
erector spinae muscles are found (semispinalis, multidus,
and rotatores muscles; see Fig. 19.21). e erector spinae
muscles are innervated by the posterior rami of the thoracic
nerves. e fascia invests the erector spinae muscles dorsally
and ventrally. e dorsal layer constitutes the thoracodorsal
fascia. Laterally, the thoracodorsal fascia blends with the
aponeurosis of the transverse abdominis muscle; caudally it
attaches to the iliac crest and lateral crest of the sacrum.10
Posterior thoracic spine approaches typically exploit planes
that avoid direct injury to the nerves that innervate the posterior musculature.
Erector
spinae
Latissimus
dorsi
Superior nuchal
line of skull
Longissimus
capitits
C1
Levator
scapulae
Splenius
capitis
Serratus post
superior
Splenius
cervicis
Iliocostal
Longissimus
spinalis
Serratus post
inferior
T12
Internal
abdominal
oblique
FIG. 19.21 (A) Muscles of the thoracic spine. (B) Intermediate and deep
muscles of the thoracic spine. (B, From An HS. Principles and Techniques of
Thoracic Surgery. Baltimore: Williams & Wilkins; 1998.)
capitis
Thoracolumbar
Deep
layer
Rectus capitis
posterior major
Superior
obliquus capitis
Inferior
obliquus capitis
Semiplinalis
capitis
Longissimus
capitis
Spinalis cervicis
Iliocostalis
cervicis
Iliocostalis
thoracis
Longissimus
cervicis
Iliocostalis
lumborum
Longissimus
thoracis
Transversus
abdominis
fascia
e ligamentous structures of the thoracic spine from
dorsal (supercial) to ventral (deep) are the supraspinous ligament, interspinous ligament, ligamentum avum, posterior
longitudinal ligament, and anterior longitudinal ligament
(Fig. 19.22). e supraspinous ligament attaches the tips of
the spinous processes. e interspinous ligament attaches
the spinous process to the adjacent spinous processes with
obliquely oriented bers. e ligamentum avum runs from
Chapter 19 Anatomy of the Anterior Cervicothoracic Spine 349
Vertebral body
Superior
Costrovertebral
costotransverse
Radiate ligament
costotransverse
Ant. longitudinal
FIG. 19.22 Ligaments of the thoracic spine. (From An HS. Principles and
Techniques of Thoracic Surgery. Baltimore: Williams & Wilkins; 1998.)
the undersurface of the trailing margin of the cephalad vertebra and inserts on the top portion of the caudad lamina. Of
all the ligamentous structures supporting the thoracic spine,
the ligamentum avum is the strongest and most robust. It
provides extension support to the adjacent vertebrae. e
posterior longitudinal ligament runs along the dorsal aspect
of the vertebrae and intervertebral discs and the anterior
longitudinal ligament runs ventrally.
pedicles, superior and inferior articular facet, transverse costal
facet, pars interarticularis, lamina, and spinous process. ere
are 12 thoracic vertebral bodies. Vertebral body size sequentially decreases from T1 to T3, then sequentially increases
to T12.13 e spinous processes in the thoracic spine project
posteroinferiorly with the tip of the spinous process overlying
the preceding vertebral body.
bodies via the transverse costal facet starting at T1. e rst
rib articulates only with T1. Ribs 1 through 7 have direct
attachments to the sternum, thus are referred to as true ribs.
Ribs 8 through 10 connect via costal cartilage to the rib above
and are called false ribs. Ribs 11 and 12 are oating ribs, and
have no attachment point other than to their corresponding
vertebral body.13 e rib heads of ribs 1 through 10 overlie the
adjoining intervertebral disc space via two types of articulations: the costovertebral articulation and the costotransverse
articulation. e costovertebral articulation is between the rib
head and the vertebral body. is articulation is stabilized by
the articular capsule, radiate ligament, and intraarticular ligaments. e costotransverse articulation is between the neck
and tubercle of the rib and the transverse process.
tion. ey are oriented in a more coronal plane and undergo
transition from T1 to T12. At T1, the superior facet faces up
and back, whereas the inferior facet faces down and forward.
Progressing caudad, the superior facet transitions to facing up,
back, and slightly lateral. e inferior facet faces down,
forward, and more medial. is orientation allows for some
articular facet
facet
Intervertebral
disc
Lateral
ligament
Medial
ligament
ligament
Transverse
process
Rib
Superior
costotransverse
ligament
Intertransverse
ligament
e thoracic vertebrae are made up of the vertebral body,
e thoracic ribs articulate with the thoracic vertebral
e facet joints of the thoracic spine have a unique orienta-
rotation. e superior facet contains articular cartilage on its
dorsal surface; the inferior facet has articular cartilage on its
ventral surface. e pars interarticularis is the portion of bone
that connects the superior and inferior articular processes.
Since the advent of pedicle screw xation and its current
widespread use for posterior instrumentation, understanding
the anatomy of the thoracic pedicle has become paramount.
e pedicle of each vertebral body is located at the base of each
facet (Fig. 19.23). ere have been numerous studies looking at
the morphology of the thoracic pedicles.
14–19
Projecting from
their respective vertebrae, thoracic pedicles angle posteriorly
and laterally. Moving from cephalad (T1) to caudad (T12), the
pedicle aims successively less medially (see Fig. 19.23). e
superoinferior pedicle diameter is larger than the mediolateral
diameter.3 e smallest pedicle diameter (medial to lateral) is
typically found at T4. In terms of strength, the medial pedicle
wall is two to three times stronger than the lateral wall.
14
e transverse process is found at the junction of the pars
interarticularis and facet. e associated nerve root is anterior
and superior to the transverse process. e associated dorsal
rami are found anteroinferiorly.1 Protecting the underlying
nerve root is an intertransverse aponeurosis.
Posterior Approaches to the Thoracic Spine
e posterior-based approaches to the thoracic spine are the
workhorse approaches for a majority of pathologies, including
degenerative, traumatic, infectious, and neoplastic conditions.
Slight variations in approach allow the surgeon access to
midline, lateral, dorsal, and ventral aspects of the spinal
column while avoiding associated morbidity with thoracotomy
approaches.
Posterior Approach for Decompressive Laminectomy and Fusion
Aer successful induction of anesthesia, the patient is placed
in the prone position. Either a Jackson frame or regular operating room bed with chest rolls is ideal. is allows the abdomen
to rest free of pressure, decreasing venous engorgement of
the epidural venous plexus, which helps minimize blood loss.
Localization is then performed with the aid of uoroscopy and
palpable landmarks. e superior border of the scapula corresponds to T3, the inferior angle of the scapula corresponds
to T7, and the most prominent spinous process corresponds
to C7. Fluoroscopic visualization of the upper thoracic region
can prove dicult secondary to overlap from the shoulders.
A combination of anteroposterior (AP) and lateral uoroscopy should be used to ensure that the appropriate surgical
level(s) is marked. e skin is then marked in the midline,
directly over the spinous process from the cephalad to caudad
surgical level.
A No. 10 blade scalpel is used to incise the skin in this
distribution. Subcutaneous dissection is performed with Bovie
electrocautery. Subperiosteal dissection is then undertaken by
separating the muscular attachments from the spinous process
and lamina. Subperiosteal dissection helps minimize blood
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350 SURGICAL ANATOMY AND APPROACHES
T1BT2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12
Transverse pedicle angle
Vertebral
vertebral notch
Transverse process
A
Superior
vertebral notch
Superior
articular facet
Spinous process
Superior
costal facet
Body
Inferior
costal facet
40
30
foramen
Pedicle
Body
Lamina
Superior articular
process and facet
Inferior
McCormack (1994)
Zindrick (1987)
Scoles (1988)
Panjabi (1991)
Berry (1987)
Superior
costal facet
Pedicle
Transverse
costal facet
Transverse
costal facet
Inferior articular
process
Spinous process
0°
loss. Supercially, in the upper thoracic spine, the rhomboid
and trapezius muscle attachments are encountered. In the
lower thoracic spine, the latissimus dorsi attachments are
encountered. Deep to these supercial attachments are the
erector spinae and transversospinal muscle attachments. e
muscles are retracted laterally and self-retaining retractors are
placed.
When performing laminectomy alone, the lateral margins
of the lamina and pars interarticularis are exposed while being
sure to avoid violating the facet joint capsule. Violating the
facet joint capsule when performing wide laminectomy can
lead to iatrogenic instability.20 Care should be taken when
20
10
0
–10
FIG. 19.23 (A) Osseous structure of the thoracic spine and thoracic vertebra. (B) Transverse pedicle angles
found in ve dierent studies. (A, From Netter FH. Atlas of Human Anatomy. 2nd ed. Philadelphia: Elsevier; 1998.
B, From McCormack BM, Benzel EC, Adams MS, et al. Anatomy of the thoracic pedicle. Neurosurgery. 1995;37:
303-308.)
exposing the lateral margins of the pars interarticularis and
facet joints, as unnecessary bleeding can result.
e next step is performing the laminectomy. ere are
several ways to accomplish laminectomy in the thoracic spine.
A gentle, relatively atraumatic technique that minimizes pressure on the thoracic cord is to use a high-speed burr to create
a trough on both sides of the lamina at the junction of the
lamina and corresponding facet joint. To complete the troughs,
No. 1 and No. 2 Kerrison rongeurs are used. Care should be
taken to avoid violating the underlying dura during this
process. Once the troughs are complete, the lamina is gently
lied and underlying ligamentum avum and adhesions are
Chapter 19 Anatomy of the Anterior Cervicothoracic Spine 351
gently released from the undersurface of the caudad margin
of the lamina. Using a combination of curettes, No. 1 and No.
2 Kerrison rongeurs, the laminectomy is completed. Further
decompression, including partial medial facetectomy and
foraminotomy, is performed depending on the degree of
decompression necessary.
Aer ensuring hemostasis has been achieved, the wound is
closed in standard fashion.
Transpedicular Approach
e posterior transpedicular approach was rst described by
Patterson and Arbit in 1978 for approaching thoracic disc
herniations.21 As the approach has gained popularity, its
indications have expanded to include tumor, infectious, and
traumatic etiologies. e approach can be performed unilaterally or bilaterally depending on the need for isolated access to
the posterolateral aspect of the vertebral body and disc space
on one side versus the need for bilateral access, as in the case of
tumors aecting both nerve roots or for complete discectomy.
A unilateral transpedicular approach is less destabilizing
than a bilateral transpedicular approach. However, the bilateral transpedicular approach can allow one to perform nearcircumferential decompression, such as in the case of extensive
tumor involvement or if there is a need for complete discectomy. In fact, this approach can be used to perform circumferential decompression and vertebrectomy.
transpedicular approaches are being performed, serious consideration should be given to stabilization to prevent iatrogenic
instability and deformity.
Aer intubation, the patient is placed in the prone position
on a Jackson table or radiolucent table with chest rolls. Image
intensication is then used to mark the surgical levels. Standard sterile prep and drape is performed.
A midline incision is then made over the surgical level(s)
being addressed. Subperiosteal dissection is performed laterally until the lamina and facet joint of the level to be treated
is exposed. is is undertaken bilaterally if bilateral transpedicular approaches are being used.
e pedicle overlying the disc herniation or level to be
treated is identied. For a thoracic disc herniation, the caudal
pedicle is adjacent to the intervertebral disc (i.e., the T9–T10
disc is adjacent to the T10 pedicle). To help further identify
the pedicle, spinal cord and aected nerve root laminectomy
can be performed prior to pedicle removal. Once the pedicle
is identied, it is entered with a high-speed burr and the
central, cancellous portion is removed to the depth of the
pedicle vertebral body junction. Intraoperative uoroscopy
can be useful for this portion of the procedure to help safely
guide the surgeon down the pedicle as well as aid in depth of
resection. Aer removal of the cancellous portion of the
pedicle has been achieved, the remaining cortical wall is taken
down with either a pituitary rongeur or down-biting curettes.
In the classical approach, only the medial and superior borders
of the pedicle are resected, but the entire pedicle can be taken
down if necessary. Decompression is then performed in a
lateral to medial trajectory, with care taken to avoid injuring
the spinal cord and nerve root (Fig. 19.24).
22,23
If bilateral
FIG. 19.24 The transpedicular approach.
Costotransversectomy
First described in 1894 by Menard, the costotransversectomy
approach was originally created for the treatment of spinal
abscess.24 Since its rst description, many variations and
alternate indications have been established. e approach
allows near-circumferential access to the anterior thoracic
spine while avoiding the potential morbidity associated with
an anterior approach. Additionally, this approach allows for
single-stage surgery, with the ability to decompress and stabilize simultaneously. Current indications include thoracic disc
herniations, fractures, tumor, infection, and deformity.
Traditionally, the patient is placed in the prone position
on a Jackson table or radiolucent table with chest rolls.
Alternatively, the patient can be placed in a semiprone or
modied lateral decubitus position. e table should allow
circumferential uoroscopic visualization of the surgical
level. Having the ability to airplane the table can help aid in
visualization.
Fluoroscopy is used to help mark the skin incision at
the appropriate surgical level(s). Sterile prep and drape is
performed. Attention should be given to ensuring that wide
draping is achieved, as this approach involves partial rib
exposure.
ere are several incision variations that can be used. Ultimately, the decision regarding which incision to use depends
on the indication for the procedure and whether or not laminectomy and/or instrumentation is required. Traditionally, a
curvilinear incision approximately 8 cm lateral to the spinous
process of the surgical level that is 10 to 13 cm in length has
been described (Fig. 19.25). 4 Since most procedures involve
scenarios requiring simultaneous laminectomy and/or stabilization, the following technique is described from a midline
posterior approach.
Using the previously described standard posterior approach
to the thoracic spine, subperiosteal dissection is performed
exposing the lamina and transverse process. Further lateral
dissection is carried posteriorly and laterally along the corresponding rib approximately 6 to 8 cm depending on the
extent of exposure required. e transverse process and rib
25
SECTION
III
352 SURGICAL ANATOMY AND APPROACHES
FIG. 19.25 A median or paramedian incision may be made straight or
curved centered over the desired vertebral level. Traditionally, a curvilinear
incision about 8 cm lateral to the intended spinous process and 10 cm to
13 cm long has been used.
FIG. 19.26 The rib and its arthrodial junction can now be disarticulated.
A subperiosteal dissection is done along the pedicle and upper and lower
vertebral body to separate the pleura from the vertebral wall.
are then dissected circumferentially using a periosteal elevator, rib dissector, or curettes. Great care should be taken to
avoid violating the underlying pleura and the neurovascular
bundle, which travels on the underside of the rib. Once
entirely skeletonized, the rib is cut laterally with a rib cutter
or large Kerrison rongeur. e rib is then gently lied up and
away from the underlying pleura and neurovascular bundle,
and disarticulated from the costovertebral joint attachment
with Bovie electrocautery or curettes, removing the rib en
bloc (Fig. 19.26). If a fusion is being performed, the rib can
be used for bone gra. e corresponding transverse process
can also be resected for further visualization of the pedicle
and lateral vertebral body. Bone bleeding is controlled with
bone wax.
Next, the lateral pedicle wall is identied and careful
subperiosteal dissection is performed along the lateral aspect
of the vertebral body with a Cobb elevator while protecting
the underlying pleura. Dissection is carried ventral until the
FIG. 19.27 A subperiosteal dissection is done along the pedicle and upper
and lower vertebral body to separate the pleura from the vertebral wall.
anterior margin of the vertebral body is reached. A malleable retractor is then placed to create a working window
and protect the underlying pleura and vascular structures
(Fig. 19.27).
Lateral Extracavitary Approach
e lateral extracavitary approach was developed by Larson
and colleagues at the University of Wisconsin in 1976, aer
expanding on the work of Menard and Capener.26 is approach
is an expansion of the costotransversectomy approach, allowing for greater exposure and visualization of the ventral thecal
sac. e indications for this approach include tumors, infection, trauma, and treatment of thoracic disc disease.27 is
approach can be utilized throughout the entire thoracic spine.
Similar to the costotransversectomy, it is a versatile approach
that avoids the need for formal thoracotomy.
e patient is placed in the prone position on a Jackson
table or radiolucent surgical bed with chest rolls. e patient
should be secured to the table to allow for bed rotation of 20
to 30 degrees if necessary.
Once positioned, localization for the skin incision is performed with the aid of the uoroscope. e patient should be
draped widely to allow for formal thoracotomy, if necessary.
Aer prep and drape, a midline incision centered over the
spinous process of the level of interest is made. e supercial
and deep fascia to trapezius and latissimus dorsi are incised.
Depending on surgeon preference, the incision can be carried
laterally in hockey stick fashion 8 cm if a wider exposure is
needed. In the lower thoracic spine, the bers of the trapezius
are close to the transverse process of the rib. A plane is now
established to expose the lateral margin of the paraspinal
muscles. Working lateral to medial, the paraspinal muscles are
elevated subperiosteally and retracted. Similar to the costotransversectomy approach, the rib of interest is skeletonized
utilizing the subperiosteal technique while being careful not
to damage the underlying parietal pleura. e transverse
process of the rib and the lamina on the operative side are
similarly exposed. e transverse process is removed. If more
exposure is required, the cephalad rib can be similarly exposed,
allowing for even greater visualization.
e rib is cut laterally with a rib cutter or large Kerrison rongeurs. As opposed to the limited rib resection with