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136 Procedure 15 | Posterior Cervical Laminoplasty
FIGURE 15-2
TL
FIGURE 15-4
FIGURE 15-3
TL
TL
Examination/Imaging
n
Upper motor neuron signs (Hoffmann, clonus, up-going Babinski reflex, and
finger escape sign)
n
Gait and balance problems
n
Difficulties with any activities requiring fine motor movements (buttoning shirt,
writing)
n
Wasting of hand intrinsic musculature
Procedure 15 | Posterior Cervical Laminoplasty 137
A
FIGURE 15-5, A-B
T R E A T M E N T OP T I O N S
• Anterior cervical diskectomy and fusion
(ACDF)
• Anterior cervical corpectomy and fusion
(ACF)
• Posterior cervical laminectomy
+/− fusion
B
n
Imaging studies
• Radiographs: used to examine overall alignment, amount of spondylosis,
instability, OPLL
• Magnetic resonance imaging (MRI): used to evaluate cord morphology and
cord parenchymal changes, soft tissue structures
n
Computed tomography (CT) myelography: useful in patients unable to be evalu-
ated by MRI and may be better for osseous evaluation and previous hardware
placement.
n
Figure 15-5 shows axial MRI (A) and CT (B) myelogram demonstrating left-sided
compression. The choice of opening side depends on the side of neurologic
compression. In this example, the opening side would be the left side.
Surgical Anatomy
n
C2, C7, and T1 spinous processes are prominent and palpable in the superficial
cervical spine (Figure 15-6).
n
The spinous process of C2 is bifid and a source of multiple muscular attachments
that should be preserved (Figure 15-7).
Planned incision
FIGURE 15-6
C2 spinous process
C7 spinous process
T1 spinous process
138 Procedure 15 | Posterior Cervical Laminoplasty
Posterior atlanto-
occipital membrane
Vertebral artery
FIGURE 15-7
Greater occipital nerve
Obliquus capitis superior
Rectus capitis posterior minor
Rectus capitis posterior major
Obliquus capitis inferior
Third occipital nerve
Ligamentum flavum
Intertransversarius
P O S I TI O N I N G PE A R L S
• Fiber-optic intubation for severe
myelopathy or stenosis
P O S I TI O N I N G EQ U I P M EN T
• Operating room table with Mayfield
attachment
• Mayfield tongs
Positioning
n
The patient’s hair is shaved up to the inferior margin of the occiput.
n
The patient is placed prone with Mayfield tongs onto an operating room table
with a Mayfield attachment.
n
The head is positioned with the “chin-tucked and slightly forward-flexed” to
facilitate exposure.
n
Operating room bed positioning
• Knees are flexed first to prevent patient from sliding.
• A reverse Trendelenburg position of 30 degrees is used, which facilitates
exposure, reduces venous bleeding, and allows the cervical spine to be more
parallel to the floor for ease of operation (Figure 15-8).
n
After the patient is positioned, the shoulders are taped down.
n
A radiopaque skin marker may be used to estimate incision length, but C2 and
C7 spinous processes are prominent and provide a good estimate of incision
length.
Procedure 15 | Posterior Cervical Laminoplasty 139
FIGURE 15-8 FIGURE 15-9
FIGURE 15-10 FIGURE 15-11
P O RTA L S / E X P O S U R ES
P E A R LS
• A precise midline approach to the
posterior elements and subperiosteal
dissection will minimize bleeding from
this approach.
Portals/Exposures
n
The spinous processes of C2 and C7serve as superficial landmarks for the surgi-
cal incision.
n
Injection of local anesthetic with epinephrine into the paraspinal musculature
minimizes bleeding (Figure 15-9).
P O RTA L S / E X P O S U R ES
P I T F A L L S
• Dissection of the extensive muscular
attachments of C2 spinous process
• Muscular dissection into the
paracervical musculature may cause
notable bleeding.
• Spina bifida
• Previous posterior cervical surgery
resulting in dural adhesions
n
Follow the nuchal line to the spinous processes (Figure 15-10). A careful midline
dissection through the nuchal ligament minimizes muscular bleeding.
n
Use standard exposure to the cervical spine from C2 to T1 (Figure 15-11).
n
Perform subperiosteal dissection of the paracervical musculature out laterally to
the medial edge of the facet joint.
n
Self-retaining retractors are placed.
Procedure
n
The authors will describe a modified “open-door laminoplasty” technique origi-
nally described by Hirabayashi and colleagues. The technique entails variations
P O RTA L S / E X P O S U R ES
E Q U I PM E N T
• McCullough self-retaining retractors
on laminoplasty types: They can be generally described as unilateral hinge
(“open-door”) and bilateral hinge (“French door”) with supplemental procedures. Various supplemental methods are used to keep the laminoplasty door
open (laminoplasty plates, suture use, and bone graft).
140 Procedure 15 | Posterior Cervical Laminoplasty
S T E P 1 P EA R L S
• If the hinge side is inadvertently burred
bicortically, salvage plates may be used.
S T E P 1 P IT FA L L S
• Burring into the facet joint may cause
postoperative neck pain.
• Overzealous resection of bone from the
hinge side may turn a laminoplasty into
a laminectomy.
S T E P 1
I N S T RU M E N T A T I O N /
I M P L AN TAT IO N
• Surgical microscope
• AM-8 Midas Rex high-speed drill
(Midas Rex Pneumatic Tools, Fort
Worth, Texas)
Step 1
n
C3-7 spinous processes are removed to facilitate exposure and if spinous
process sutures are not used.
n
A high-speed AM-8 burr (Midas Rex Pneumatic Tools, Fort Worth, Texas) is used
to make two bony troughs at the medial aspect of the lateral mass or the
lamina–facet junction (Figure 15-12).
n
The lamina is thicker at the superior margin and thinner inferiorly.
n
On the hinge side, only one cortical layer and cancellous bone is removed with
a burr, taking care not to burr through the second cortical layer.
n
The opening side is removed with a burr bicortically (cortical-cancellous-cortical
bone layer).
Step 2
n
Ligamentum flavum from the C2-3 interspace and C7-T1 interspace is
excised with a Kerrison rongeur (Figure 15-13, A and B). Ligamentum flavum is
excised at both interlaminar spaces at the cephalad and caudad levels of the
laminoplasty.
n
Any dural adhesions on the opening side are freed with curettes and 2-mm
Kerrison rongeurs (Figure 15-14).
FIGURE 15-12
A
B
FIGURE 15-13, A-B
Procedure 15 | Posterior Cervical Laminoplasty 141
S T E P 3 P EA R L S
• Be careful not to be overly aggressive.
A 6- to 8-mm opening achieves good
decompression with less risk of
posterior migration of spinal cord and
root tension.
• Allograft trial spacers (Figure 15-15) are
used to estimate graft size.
• Allograft spacers are applied on the
opening side (Figure 15-16).
S T E P 3
I N S T RU M E N T A T I O N /
I M P L AN TAT IO N
• Machined bone allograft
S T E P 4 P EA R L S
• If the hinge side is inadvertently burred
bicortically, salvage plates may be used.
S T E P 4 P IT FA L L S
• Postoperative closing of laminoplasty
door causing recompression
Step 3
n
The hinge side is carefully opened by the operative assistant, using small
forward-angled curettes or skin hooks.
n
The lamina is opened slowly to allow gentle creep of the lamina and spinal cord,
and it is opened just enough to accommodate a 6- to 8-mm bone graft.
Step 4
n
Laminoplasty plates are sequentially applied, and typically, the lateral mass and
laminar screws are 8 and 6 mm deep, respectively (Figures 15-17 and 15-18).
n
Plates allow immediate postoperative stability and mobilization of cervical spine
with no bracing required.
n
Alternatively, sutures may be used to keep the laminoplasty open via spinous
process sutures tensioned on the facet joint capsule and paraspinal
musculature.
n
Hemostasis is achieved with a combination of bone wax, Gelfoam, and
thrombin.
S T E P 4
I N S T RU M E N T A T I O N /
I M P L AN TAT IO N
• Laminoplasty plates and screws or
sutures (nonresorbable), depending on
preference
FIGURE 15-14
FIGURE 15-15
FIGURE 15-16
142 Procedure 15 | Posterior Cervical Laminoplasty
FIGURE 15-17
FIGURE 15-18
P O S T OP E R AT IV E P I T F A L L S
• Nerve root palsies may occur, with the
C5 nerve root (up to 5%) being most
affected, followed by C6 and C7.
• Observation is warranted, with most
patients recovering by 6 months.
• Postoperative cervical kyphosis
• Axial neck pain
• Closure of laminoplasty door
Postoperative Care and Expected Outcomes
n
Excellent outcomes are expected from cervical laminoplasty.
n
Patient is placed in an optional soft cervical collar and encouraged to begin
early active range-of-motion exercises.
n
Physical therapy is begun 6 weeks postoperatively.
Evidence
Herkowitz HN. A comparison of anterior cervical fusion, cervical laminectomy, and
cervical laminoplasty for the surgical management of multiple level spondylotic
radiculopathy. Spine 1988;13:774-80.
Hirabayashi K, Watanabe K, Wakano K, et al. Expansive open-door laminoplasty
for cervical spinal stenotic myelopathy. Spine 1983;8:693-9.
Park AE, Heller JG. Cervical laminoplasty: use of a novel titanium plate to
maintain canal expansion–surgical technique. J Spinal Disord Tech
2004;17:265-71.
Satomi K, Ogawa J, Ishii Y, Hirabayashi K. Short-term complications and long-term
results of expansive open-door laminoplasty for cervical stenotic myelopathy.
Spine J 2001;1:26-30.
P R O C ED U R E 1 6
Anterior Thoracic
Diskectomy and
Corpectomy
Christopher C. Harrod, Andrew K. Simpson,
and Alexander R. Vaccaro
I N D I CAT I O NS P I T F A L L S
• Failure to determine nature of disk:
“hard versus soft disk” (presence of
calcification)
• Failure to identify and appreciate disk
location: central, paracentral, or lateral
• Failure to identify extent of herniation:
intradural or extradural
• Failure to incorporate adjacent partial
corpectomies for safe excision of hard
disks
• Medical comorbidities or inability to
tolerate single-lung ventilation (tolerate
anterior approaches)
T E C H NI Q U E S
C O N T RO V E R S IE S
• Approach-related morbidity: Traditional
anterior thoracotomy is difficult
for patients with significant
cardiopulmonary disease and often
incurs postoperative pain from rib
resection, retraction, and chest tube
sites. This approach often requires
an access surgeon. Open posterior
approaches can denervate paraspinal
musculature and have higher blood
losses and infection rates.
• Thoracoscopic indications and role:
The ideal use is in anterior, small,
midthoracic (T4-11), noncalcified disks
in nonobese patients. A steep learning
curve and need for specialized
equipment and training (often with
a thoracic surgeon) exist.
Contraindications include previous chest
trauma, surgery, adhesions, infection, or
cardiopulmonary disease, precluding
single-lung ventilation.
Indications
n
Various spinal cord compressive pathologies: progressive myelopathy, lower
extremity weakness, or recalcitrant unrelenting radiculopathy
n
Thoracic disk herniations (TDH): soft or hard (calcified)
n
Ossification of posterior longitudinal ligament (OPLL)
n
Tumor: primary or metastatic
n
Fracture
n
Deformity progression
n
Osteomyelitis: pyogenic, tuberculous
Examination/Imaging
n
Thoracic spinal pathology is often marked, with either no or minimal complaints,
and can mimic cervical disk, cardiopulmonary, abdominal, aortic, intrinsic
myopathic, or renal calculus disease, requiring a thorough evaluation of all
pathologies.
n
Most patients with thoracic disk disease are asymptomatic, but thoracic
magnetic resonance imaging (MRI) demonstrates that approximately 73% of
adult patients have positive MRI abnormalities, including cord deformation
in 29%.
n
Varied clinical presentations are the norm for patients with symptomatic disks
and include thoracic pain (anterior bandlike radicular chest pain), axial back
pain, weakness, bowel or bladder frequency, and incontinence or urgency.
n
Physical examination can demonstrate upper extremity weakness, numbness,
Horner syndrome (T1 disk), lower extremity numbness and weakness (lower
thoracic disk), long tract myelopathic signs, spasticity and hyperreflexia, gait
abnormalities, and sphincter dysfunction.
n
Imaging typically consists of plain film radiographs, computerized tomography
(CT), MRI, or a CT myelogram (if MRI is contraindicated).
n
Plain films are important in helping to establish the number of lumbar and
thoracic segments on standing 3-foot films and provide a helpful measure for
counting both the number of ribs and lumbar segments that will be utilized
during preoperative and intraoperative fluoroscopy. Sagittal and coronal deformity is best evaluated on plain films. Pathologic fractures as well as calcified
disks can be noted on plain radiographs. Figure 16-1, A and B, shows preoperative anteroposterior (AP) and lateral radiographs of the thoracic spine, respectively, demonstrating slight disk space collapse and posterior osteophytes at
T11-12 (
cross
). Twelve ribs and five lumbar segments are present.
• Expanding minimally invasive posterior
techniques: Proponents argue that
morbidity is low with respect to
regional anatomy preserved. Limitations
include training in minimally invasive
surgeries and use of endoscopy.
Conversion to open approaches is
possible if excessive bleeding or
durotomy occurs. Additional studies are
needed to better define indications and
outcomes.
Procedure 16 | Anterior Thoracic Diskectomy and Corpectomy 145
A B
FIGURE 16-1, A-B
A B
FIGURE 16-2, A-B
n
MRI is most useful for evaluating normal and pathologic soft tissues (ligaments,
disk) and neural elements. TDHs, tumors, infection, and root or intrinsic spinal
cord lesions are best distinguished on MRI. Sagittal full-length spinal scout MRI
assists in intraoperative identification of level when using fluoroscopy.
n
CT scans are often helpful for evaluation of fractures, OPLL, calcified TDHs, bony
anatomy and landmarks, degree of spinal canal compromise, and planning for
ideal corpectomy resections and instrumentation (orientation or location, length,
and size). Figure 16-2 shows preoperative midsagittal (A) and axial (B) computed tomography (CT) images of the T11-12 motion segment, demonstrating
severe spinal canal stenosis, slight disk space collapse, and posterior osteophytes at T11-12 with measurements noted for bony resection and interbody
reconstruction (
cross
). The degree of spinal canal compromise, amount of ideal
bony resection, and planned instrumentation (orientation or location, length,
size) can be estimated.
146 Procedure 16 | Anterior Thoracic Diskectomy and Corpectomy
n
Adjacent hemicorpectomy and instrumentation (cage-screw) planning can be
done based on preoperative sagittal and coronal reconstructions.
n
Preoperative transpedicular polymethylmethacrylate (PMMA) can be performed
1 or 2 days before surgery in morbidly obese individuals via CT or fluoroscopy
to ensure appropriate level identification intraoperatively.
n
Pulmonary function tests (PFTs) can identify and quantify preoperative cardio-
pulmonary obstructive, restrictive, or diffusion-limiting pathologies in marginal
T R E A T M E N T OP T I O N S
• Thoracotomy (transthoracic transpleural
or retropleural)
• Thoracoscopic assisted
• Laminectomy
• Transpedicular diskectomy
• Transfacet diskectomy (pedicle sparing)
• Costotransversectomy
• Lateral extracavitary approach
• Minimally invasive posterior approaches
candidates.
n
Vascular studies (MRI, CT, or standard angiography) can aid in localization of
normal spinal cord vasculature or embolization of hypervascular lesions (metastatic lesions).
n
Provocative diskography is advocated by some to delineate which disk(s) might
be a pain generator in multilevel thoracic disk herniations noted on MRI after
failure of conservative treatment options for thoracic axial pain.
n
Preoperative or intraoperative electromyography (EMG), nerve conduction
studies (NCS), transcranial motor evoked potentials (tcMEPs), and somatosensory evoked potentials (SSEPs) are helpful in establishing and monitoring baseline neural function.
Surgical Anatomy
n
Right-sided thoracotomy is best indicated for upper thoracic (T1-4) lesions (typi-
cally third rib resection), thus avoiding thoracic duct; aorta and arch are more
left sided in the upper thoracic spine.
n
Left-sided thoracotomy is best for mid- to lower thoracolumbar (T4-L2) pathol-
ogy. The liver is the main obstruction to right-sided thoracoabdominal approaches
(thoracolumbar). The aorta is more resilient than the vena cava, moves anteriorly
as one moves caudally, and segmentals are more easily ligated than with a
right-sided approach.
n
“Peaks” (disks) and “valleys” (vertebral bodies) define the anterolateral thoracic
spine.
n
Superficial to deep muscle layers, posteriorly, include the trapezius, latissimus
dorsi, rhomboid major, and serratus posterior, before reaching the rib. Anterolaterally, the rib periosteum lies under the skin and fat, whereas the external,
internal, and innermost intercostal muscles; parietal pleura; pleural space; then
visceral pleura (and subjacent lung) are encountered if a rib-sparing technique
is chosen.
n
Rib numbering: Always count the number of ribs preoperative (i.e., 12 ribs). In
patients with 12 ribs, the twelfth rib always leads to the T11-12 interspace.
n
A cephalad rib (one to two ribs above the most affected level) should be
removed in the midaxillary line for corpectomy approaches, to give adequate
proximal exposure.
n
Direct spinal canal decompression centered on a single disk space mandates
that the rib leading to that disk space be removed (remove the eighth rib for
the T7-8 disk).
n
The first rib lies within the second rib and is quite difficult to identify on intra-
operative imaging. Removal allows access to cervicothoracic lesions (up to C6).
n
Rib anatomy is important for orientation. Ribs 2 to 10 lead to the costotrans-
verse joint (rib neck), then to the disk space (rib head). Ribs 10 to 12 tend to
fall at or below the caudal vertebral pedicles (i.e., the desired disk space is often
more cranially located). Figure 16-3 shows rib head anatomy is important for
orientation. A coronal CT image at the level of the costovertebral joints is shown.
n
Intercostal arteries originate posteriorly from the aorta and anteriorly from the
internal thoracic artery. They typically lie at the midwaist of the vertebral body.
n
The neurovascular bundles lie on the inferior aspect of each rib, and avoidance
is crucial.