Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 37 potx

Identify and regularly
check the pulsation
of the carotid artery
level localization. The structures at risk during this approach have been listed
above. A deleterious pitfall is the risk of unintentionally retracting the carotid
artery medially instead of laterally. Therefore, the pulse of this artery must be
palpated to ensure that the artery is indeed lateral.
The overall risk of operative complications remains small but significant [72].
In 450 cases of anterior cervical discectomy, the rates of recurrent nerve palsy
and Horner’s syndrome were 1.3% and 1.1%, respectively [9]. However, the true
rate of nerve root injury based on laryngoscopy is substantially higher (24%)
[34]. Apfelbaum suggested monitoring endotracheal tube (ET) cuff pressure and
release of the pressure after retractor replacement or repositioning has been
used, which enables the ET to be recentered within the larynx [4]. The natural
history of a recurrent nerve lesion is benign [34]. Complete recovery of vocal
cord function was documented in 26 (93%) of 28 patients who had undergone a
thyroidectomy [46]. Dysphagia is a not uncommon problem after anterior cervi-
cal spine surgery. Overall the incidence of dysphagia 2 years after anterior cervi-
cal spine surgery was 13.6% based on the analysis of 348 cases [43]. Risk factors
for long-term dysphagia after anterior cervical spine surgery include gender,
revision surgery, and multilevel surgery. The use of instrumentation, higher lev-
els, or corpectomy versus discectomy did not significantly increase the preva-
lence of dysphagia [43]. Ve r te br a l a r te r y i n ju r y is a rare (0.3%) complication in
cervical discectomy [10]. However, in a report on 185 corpectomies, the vertebral
artery was injured in four patients [18].
Posterior Approach to the Cervical Spine
The anterior and posterior approaches are both frequently used to approach the
cervical spine in a variety of disorders [58]. However, usually the anterior
approach is preferred because of the minimal collateral soft-tissue damage. The
posterior approach necessitates dissecting the neck muscles, which can be
related to persistent postoperative neck pain.

Indications
The posterior approach to the cervical spine is predominantly indicated in cases
with multisegmental degenerative changes or with craniocervical disorders
(
Table 2):
Table 2. Indications for the posterior approach to the cranio-cervical-thoracic spine (C0–T)
spondylotic radiculopathy cervical fracture/instability
spondylotic myelopathy chronic dens fractures
cervical instability in rheumatoid arthritis tumors
multisegmental degenerative changes infections
spinal deformities
Patient Positioning
A Mayfield clamp
is preferred for the
headrest/fixation
The positioning of the patient in the prone position is best accomplished using a
Mayfield head clamp (
Fig. 3). The clamp is applied before turning the patient into
the prone position. This fixation avoids pressure sores on the face, which are not
infrequent when using other types of headrest (e.g. the horseshoe type). We use
a carbon fiber clamp, which allows for anteroposterior imaging. The shoulders
342 Section Surgical Approaches
Figure 3. Patient positioning for posterior cervical spine surgery
Positioning of the patient with a Mayfield clamp and electrodes on the head for neuromonitoring.
and arms (parallel to the body) are pulled down using nylon tapes to expose the
cervical spine as much as possible. A footrest allows the whole table to be tilted
head up, which accommodates the surgical approach.
Surgical Exposure
Landmarks for Skin Incision
The landmarks of skin incision are:

external occipital protuberance
spinous processes C2–C7
The skin incision is along the midline from the external occipital protuberance
towards caudal depending on the target region. When a short level exposure is
attempted, image intensifier control is recommended to avoid unnecessary
detachment of the posterior spinal muscles (
Fig. 4 a).
Superficial Surgical Dissection
After skin incision and splitting of the subcutaneous tissue, the superficial surgi-
cal dissection should first identify the nuchal ligament. With a diathermy knife
the muscles are detached subperiosteally from the spinous process. The superfi-
cial muscle layer consists of (
Fig. 4 b):
trapezius muscle
posterior serratus muscle
splenius capitis muscle
Surgical Approaches Chapter 13 343
ab
cd
Figure 4. Surgical anatomy of the posterior cervical approach
a Landmark for skin incision. b Superficial and intermediate muscle layers. c Exposure of the craniocervical junction with
osteotomy of the spinous process for osteoligamentous muscle detachment.
d Surgical anatomy at the craniocervical
junction.
The posterior cervical
exposure can lead
to significant bleeding
Theintermediatemusclelayerconsistsof:
semispinalis capitis muscle
After sharp detachment the muscles are pushed laterally as one conglomerate

with sponge rolls using a Cobb raspatory. Dissection of each muscle layer is
unnecessary. In some patients, heavy bleeding is encountered which has to be
borne in mind when performing this approach. Dense packing of the space
between the spinous process and the laterally retracted muscles helps to control
the bleeding. When the spine is exposed the bleeding usually stops, i.e. bleeding
vessels can easily be identified and coagulated. During the superficial dissection
344 Section Surgical Approaches
care has to be taken not to injure the greater occipital nerve (Fig. 4b), necessitat-
ing a midline approach.
Deep Surgical Dissection
For exposure of the craniocervical junction, it is recommended to osteotomize
with a chisel (or oscillating saw) the muscle insertion of the deep muscle layer from
the spinous process of C2 (
Fig. 4c
). The deep muscle layer consists of cranially:
rectus capitis posterior major and minor muscle
oblique capitis inferior muscle
and caudally:
multifidus muscle
semispinaliscervicismuscle
The rationale for an osseous detachment is the better refixation of these muscles
to counteract postoperative kyphosis.
Exposure of the atlantoaxial
joint jeopardizes the 2nd
cervical nerve
When exposing the craniocervical junction (Fig. 4d), care has to be taken not
to injure the:
vertebral artery
second cervical nerve (greater occipital nerve)
third cervical nerve

The vertebral artery turns around the lateral mass of the atlas from lateral to
medial and disappears into the foramen magnum through the atlanto-occipital
membrane. The second cer vical nerve exits the spinal canal medial to the facet
joint, crosses that joint posteriorly in a horizontal direction and curves around the
oblique capitis inferior muscle before it runs cranially to innervate the occipital
skin. The third cervical nerve exits the foramen and separates the posterior ramus,
which runs medial to the second cervical nerve on its course to the occiput.
Wound Closure
In cases in which the insertion of the neck muscles has been detached from the
tip of the spinous process with an osteoligamentous flap, a transosseous suture of
the detached muscle is done with a slowly dissolving suture. The wound is closed
with one or two subfascial suction drainages. The fascia, subcutaneous tissue and
skin are sutured in separate layers.
Pitfalls and Complications
Exposure of C1 can cause
vertebral artery injury
The vertebral artery is at risk when a sublaminar wire is passed around the arch of
C1. It is therefore mandatory to start in the midline to subperiosteally liberate the
atlanto-occipital membrane from the bone with a blunt probe before the wire is
passed with a wire passer (Dechamps). During the exposure of the atlantoaxial
joint, the second cervical nerve is endangered because of its horizontal course over
the posterior aspect. The craniocervical junction is highly vascularized by a large
venous plexus. Blind coagulation may jeopardize the second or third cervical nerve.
Right-Sided Thoracotomy
The thoracotomy approach for the treatment of spinal disorders has been pio-
neered by Capener [12] and Hodgson [19, 31, 32]. Today, it has become a stan-
Surgical Approaches Chapter 13 345
If not determined by the
pathology, the right sided
approach is preferred

dard approach for the treatment of thoracic spinal disorders including defor-
mity, tumor or infection. In deformity surgery, the approach is always on the
side of the apex of the curve, i.e. a right-sided thoracotomy is chosen for a right-
sided curve. In cases in which the spinal pathology does not dictate the side of
the thoracotomy, the right side is preferred because of the contralateral position
of the aorta.
Indications
The indication for a thoracotomy is a spinal pathology located between T4 and
T10 (
Table 3):
Table 3. Indications for a thoracotomy (T4–T11) and thoraco-phrenico-lumbotomy (T9–L5)
spinal deformities thoracic fractures/instabilities
degenerative disorders tumors
infections
Patient Positioning
The patient is positioned in a left-sided decubitus position on a soft rubber mat-
tress. Alternatively, a vacuum mattress can be used which is helpful in large
patients and better stabilizes the patient. Both arms are positioned at 90 degrees
elevation and flexion of the elbow (
Fig. 5a, b). The legs are positioned straight
with the right leg on top of the left leg. We use a foam rubber block with a cavity
forthelowerleg.Therightlegcantheneasilybepositionedontopoftheblock.
The symphysis and the sacrum are supported by pads to avoid the patient rolling
over.
Surgical Exposure
Landmarks for Skin Incision
Double-check the correct
side of the thoracotomy
A deleterious complication is awrong side thoracotomy. Therefore, it is manda-
tory to double-check the side of the thoracotomy at the beginning of the sur-

gery.
Image intensifier control
optimizes the spinal access
Furthermore, it is of great importance to center the incision over the pathol-
ogyandcorrectlyselectthetargetribortheintercostalspace.Therelationship
between the intercostal space and the vertebral level is dependent on how oblique
or horizontal the ribs curve to the sternum (
Fig. 6a). As a rule of thumb, the rib
resected determines the highest vertebral level which can be reached (e.g. resec-
tion of the 7th rib allows T7 to be reached). It best exposes the vertebra two levels
below the origin of the resected rib (e.g. resection of the 7th rib allows the best
exposure of T9). This is crucial when a mini-open exposure is attempted. Because
of the variant forms of the ribcage, we recommend checking the correct level
with an image intensifier. Nothing jeopardizes the success of an operation so
much as an inappropriate exposure.
Superficial and Intermediate Surgical Dissection
The skin incision ranges from the lateral border of the paraspinous musculature
to the sternocostal junction of the rib which has to be resected. After the incision
of the subcutaneous tissue, the latissimus dorsi muscle and the anterior serratus
muscle also have to be divided over the course of the target rib with a diathermy
346 Section Surgical Approaches
a
b
Figure 5. Patient positioning for right-sided thoracotomy
a Anterior view. b Posterior view.
knife. It is recommended to only partially transect the latissimus dorsi muscle
and lift it off the ribcage with a Hohman retractor (
Fig. 6 b). When exposing the
anteriorpartoftheribcage,careshouldbetakentosparethe:
long thoracic nerve (innervates the serratus muscle)

Therefore, the serratus muscle should be dissected as far distally as possible. This
is particularly important when high thoracic levels are exposed.
The periosteum of the rib is dissected in the middle of the rib and liberated
with a blunt dissector. A rib stripper is used to further liberate the rib. The rib is
cut with a rib cutter as far posteriorly and anteriorly as possible to allow for a
good exposure. When a thoracotomy is done with preservation of the rib, the
intercostal muscle layer is cut in the lower half to preserve the neurovascular
bundle which lies directly below the inferior edge.
Surgical Approaches Chapter 13 347
ab
cd
ef
Figure 6. Surgical anatomy for right-sided thoracotomy
a Landmark for skin incision. b Superficial dissection. c Dissection of the rib for resection. d Exposure of the anterior spi-
nal column.
e Deep surgical dissection with ligation of the segmental vessels. f Insertion of a thorax drain and closure of
the thorax.
348 Section Surgical Approaches
Deep Surgical Dissection
The parietal pleura is picked up with anatomical tweezers and opened with scis-
sors. Depending on the necessary exposure, the anesthetist may then deflate the
lung. The intercostal space is widened with a rib spreader (
Fig. 6d). The lung can
be covered with an abdominal towel and retracted. The anterior vertebral col-
umn becomes visible. The parietal pleura is lifted off the vertebral column with
anatomical tweezers and opened to expose the segmental vessels (
Fig. 6e). The
segmental vessels are mobilized with an overhold and ligated 3–4 cm anterior to
the rib head. In severe spinal deformities the segmental vessel can first be
clamped to see whether a ligation has an influence on the blood supply of the spi-

nal cord, which would result in a decrease in evoked potentials (neuromonito-
ring). A sponge stick is used to further expose the vertebral bodies and interver-
tebral discs.
Wound Closure
Close the parietal pleura
whenever possible
The parietal pleura is sutured whenever possible and it is attempted to cover the
implant with pleura. Before closing, one or two thorax drains are inserted. We
recommend using large rather than small drains particularly when significant
bleeding has occurred. Small drains are easily blocked by blood coagula. The
skin is incised about one level below the target intercostal level in order to allow
for an anatomical closure when removing the drain. A large towel clamp is
inserted through the wound to pick up the drain and pull out the drain from the
inside. The drain is manually placed at the apex of the thorax rather anteriorly.
Depending on the bleeding, we prefer to insert a second drain, which is placed
over the spine posteriorly. A rib approximator is used to narrow the ribs and fix
them with a suture running around both ribs including the intercostal soft tissue
but avoiding the neurovascular bundle (
Fig. 6f). We recommend placing all
sutures first before tightening them. At this stage, the anesthetist is asked to rein-
flate the lung. Care has to be taken that all parts of the lung are inflated to avoid
atelectasis. If parts of the lung are not inflatable, a gentle manual massage of the
lung tissue usually resolves this problem. The muscle and soft tissue layers cover-
ing the ribcage are sutured sequentially.
Pitfalls and Complications
We have already mentioned the deleterious pitfall of opening the thorax on the
wrong site (wrong site surgery).Theanteriorapproachtothespinecarriesa
higher risk of serious complications than the posterior route for obvious reasons.
The most frequent problems associated with this approach are:
access through an intercostal space too high or too low in relation to the

main pathology
injury to the lung when incising the rib bed or opening the pleura
injury to segmental vessels when exposing the spine
injury to the azygos vein and aorta
dissection into the intervertebral foramen
Details on the handling of complications associated with this approach are cov-
ered in Chapter
39 .
Surgical Approaches Chapter 13 349
Left-Sided Thoraco-Phrenico-Lumbotomy
This approach gives
excellent access to the
thoracolumbar junction
This approach was introduced to spinal surgery by Hodgson mainly in the con-
text of spinal tuberculosis [31, 32]. Similarly to a thoracotomy, an approach to the
thoracolumbar junction is possible from the left as well as from the right side.
When the pathology does not dictate the side of the approach, an access from the
left side is preferred because the liver and the inferior vena cava are not hinder-
ing the approach [11].
Indications
If not determined by the
pathology, the right sided
approach is preferred
The indication for a thoraco-phrenico-lumbotomy is a spinal pathology located
between T9 and L5 and similar to those of a thoracotomy (
Table 3).
Patient Positioning
The patient is positioned on the right side inversely to a right-sided thoracotomy
(
Fig. 7a, b).Thetablecanbeslightlybentabovethelevelofthepelvistoincrease

the distance between pelvis and ribcage.
Surgical Exposure
Landmarks for Skin Incision
Depending on the target level, it is usually recommended to resect the 10th rib
(T10–L5). In cases with more proximal pathology, the 9th rib can be resected
(T10–L5) (
Fig. 8a).
Superficial Surgical Dissection
After the incision of the skin and the subcutaneous tissue at the thoracolumbar
junction, the superficial muscle layer is exposed consisting of (
Fig. 8b):
serratus anterior muscle
latissimus dorsi muscle
external oblique muscle
Whenever possible the muscles should be split in the direction of the fibers.
Intermediate Surgical Dissection
We recommend starting with the retroperitoneal approach. After splitting the
externalobliquemuscle,theinternalobliqueandtransversusmusclesaresplit.
With sponge sticks the peritoneal sac is mobilized to the midline and freed from
the diaphragma. In a next step, the 9th or 10th rib is resected similarly to the
method described above (
Fig. 6c
). The anterior resection is done close to the
osseous-cartilage transition of the rib. The costal cartilage is split and the
diaphragma is transected circumferentially about 2 cm medial to its insertion
at the thorax wall. It is strongly recommended to use holding sutures bilateral
to the transection to allow for a better orientation during diaphragma repair
(
Fig. 8d, e
).

350 Section Surgical Approaches
a
b
Figure 7. Patient positioning for left-sided thoraco-phrenico-lumbotomy
a Anterior view. b Posterior view.
Deep Surgical Dissection
The left crus of the diaphragma is transected about 2 cm above the medial and
lateral arcuate ligament. The parietal pleura is incised at the thoracic level as
described above. The attachments of the psoas muscle need to be mobilized pos-
teriorly. The vertebrae and intervertebral discs are further exposed with sponge
sticks and rasps. The segmental vessels need to be ligated at the target level.
Wound Closure
At the thoracic level, the parietal pleura needs to be sutured. The repair of the
diaphragma is facilitated when bilateral stay sutures were used during prior dis-
Surgical Approaches Chapter 13 351