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8
Cervical Laminoplasty
Kazumasa Ueyama, Po-Quang Chen, and Seiko Harata
Goals of Surgical Treatment
Posterior decompression and reconstruction of the cervical spinal canal.
Diagnosis
Cervical myelopathy is diagnosed precisely by physical examination. We
evaluate a patient’s status using the Japanese Orthopaedic Association’s
(JOA) functional scoring system (full mark is 17 points).
Cervical instability, alignment, and sagittal spinal canal diameter (less
than 13 mm) are checked by plain x-ray. Computed tomography (CT) is
also effective in showing the spinal canal (Fig. 8–1), osteophytes, and ossification of the posterior longitudinal ligament (OPLL). Magnetic resonance
imaging (MRI) shows the spinal cord, the subarachnoid space, and the intervertebral disc. The T2 high-intensity area in the spinal cord indicates intramedullary change.
Indications for Surgery
1. Multisegmental cervical spondylosis with a narrow canal
2. OPLL with continuous or mixed type
3. Developmental spinal canal stenosis
4. JOA score below 13/17.
Contraindications
1. Kyphotic deformity
2. Soft disc herniation
3. One- or two-level spondylosis without developmental canal stenosis
Advantages of Spinal Process Median Splitting Laminoplasty
for Cervical Myelopathy
1. Short operating time using threaded saw (T-saw) and hydroxyapatite
(HA) spacer
2. Full expansion of the spinal canal
3. Preventing postoperative kyphotic change and the formation of per-
idural scar tissue
4. Nerve root decompression with partial facetectomy
5. Spinal stability with bone graft
Disadvantages
1. Decreasing range of motion (ROM) of the cervical spine
2. Postoperative stiffness in the neck and the interscapular region
Procedure for Spinal Process Median Splitting with HA
Spacers
Laminoplasty Levels
Extent of laminoplasty is usually from C3 to C7. If there is a narrow canal at
the C2 level, this level should be included. If an instability is recognized
preoperatively, bone grafting for stabilization should be used instead of an
HA spacer.
1. Positioning: The patient is intubated and placed in the prone position
on a four-point supporting frame. Mayfield’s pin holder is safe and useful for maintaining cervical alignment in slight extension. In cases of a
second operation, the neutral position is better than the extension
position so that an airtome can be used instead of a T-saw for splitting
of the spinous process. Cervical alignment should be reconfirmed by xray before making the skin incision.
2. Skin incision: The midline incision is usually made from the C2
spinous process to the T1 spinous process. The ligament nuchae is dissected in midline.
3. Exposure of the laminae: The paravertebral muscle is detached from
the lamina using an electric cautery, Cobb’s elevator, and scissors. The
semispinal muscles inserted to the C2 lamina are detached bilaterally,
making a landmark. The posterior spines from the distal C2 to the proximal T1 are exposed. Each facet is also exposed without injury of the
capsule. The edge of each spinous process is cut, and the long spinous
process of the C6 and C7 are cut without a fracture of the lamina. The
interlaminal soft tissues from the C2-C3 to the C7-T1 are removed with
a rongeur and each yellow ligament is exposed.
4. Median splitting of the spinal process: The epidural space at C2–3 is
exposed with removal of the yellow ligament by an air drill and Kerrison rongeur. A cervical intervertebral spreader is useful for exposure of
the epidural space at C7-T1. After spreading of the C7-T1 interlaminar
space, the median split of the yellow ligament can be found. The yellow ligament is easily removed from this split. The dural membrane is
confirmed. The length of the epidural tube is measured from C7-T1 to
C2–3. Using an epidural needle (16 gauge), an epidural tube is carefully inserted from the epidural space at C7-T1, and its top is pulled
out at the epidural space at C2–3. A T-saw with 0.54-mm diameter is
passed through the tube and the T-saw is pulled out (Fig. 8–2A). The Tsaw runs in the epidural space from C3 to C7. Maintaining cervical lordosis with a lordotic keeper, median splitting of the spinal process is
started from C3 to C7. To avoid generating heat when cutting the bone,
physiologic saline solution is sprinkled simultaneously. Median splitting is achieved within several minutes. If it is difficult to insert the
epidural tube, because of, for example, a severe stenosis, the narrowest
interlaminal space should be carefully opened with the same procedure at C7-T1. Median splitting should be separately carried out. If
the T-saw is not available, using the thin Kerrison rongeur is recommended to split the remaining spinous processes one by one following
the construction of the bilateral gutter.
5. Constructing the bilateral hinge: The line of the lateral gutter is located
at the transitional area between the lamina and articular process. Using
an air drill with a 4-mm round diamond bur, the outer cortex is cut and
thinned (Fig. 8–2B). From the cephalad to the caudal direction, each
lamina is opened bilaterally with a small curet. Opening the lamina of
C7 is achieved after cutting of the yellow ligament of C7/T1.
6. Confirmation of the decompression: Adhesion between the dura and
the yellow ligament is carefully detached with a small elevator. If
possible, posterior migration of the spinal cord should be confirmed
with an intraoperative ultrasound sonography.
7. Stabilization of the hydroxyapatite spacer: Three-sized spacer trial
(12-, 15-, and 20-mm length) is done to determine the width of the
spacer. This spacer has small flanges to prevent displacement. A 15mm spacer is usually used at C3 or C4 and a 20-mm spacer at the lower
level. A bilateral bone tunnel for thread suture is made with a 2-mm
round diamond bur. A spacer is tightly fixed between the split lamina
with two nonabsorbable thread sutures (Fig. 8–2C). In case of cervical
instability, an iliac bone graft is used for the unstable segment instead
of an HA spacer, and bone chips are placed on the bilateral gutter.
8. Reattachment of the semispinal muscle: The semispinal cervical
muscles are securely reattached to the spinous process of the axis bilaterally. This procedure prevents a postoperative malalignment of the
cervical spine, especially kyphotic change.
9. Closure: A suction drainage tube is placed on the laminae and the
wound is closed layer by layer. Postoperative lateral x-ray shows normal sagittal alignment (Fig. 8–3A). CT scan shows adequate spinal
decompression (Fig. 8–3B).
Pitfalls
1. Making a lateral gutter outside occurs in facet fusion.
2. Using a T-saw may damage the spinal cord on the flexion position.
3. Beware of stabilization of the HA spacer in case of a fragile lateral gutter. A too-tight thread suture may destroy the lateral gutter.
Following to the partial facetectomy, the lateral hinge should be care-
fully made in case of myeloradiculopathy.
Complications
1. Maladaptation of the HA spacer to the splitting spinous process: The
tip of the spinous process must be cut precisely to accommodate a
spacer to the split laminae.
2. C5 nerve palsy: In the early postoperative days, pain may occur in the
shoulder or the upper arm. After that, weakness of the deltoid and the
biceps brachii muscles may develop. This palsy is motor-dominant.
Tethered nerve root by posterior migration of the spinal cord has been
suggested as a major cause. Nonsteroidal antiinflammatory drugs
(NSAIDs) and neck rest, such as neck traction in the neutral position,
are effective to relieve pain. Muscle weakness will gradually recover
within 12 months.
Postoperative Care
A suction drainage tube is removed within 24 hours. Sitting and walking is
permitted with a Philadelphia collar for 2 weeks. Three weeks postoperatively, isometric exercise of the neck and the shoulder is started, and a soft
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40
SECTION I THE CERVICAL SPINE
Eurostile
B
Figure 8–1
Preoperative lateral x-ray (A) and computed tomography (CT) (B) of
a 61-year-old man.
A
Eurostile
8 CERVICAL LAMINOPLASTY
41
■
C2
C3
C4
C5
C2
C6
C7
C7
T1
4-mm
Burr
B
A
Spacer
secured
Spacer
C
(Axial view)
Figure 8–2
Intraoperative maneuver. (A) Median splitting using T-saw. (B) Line of the lateral
gutter. (C) Stabilization of the hydroxyapatite (HA) spacer.
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42
SECTION I THE CERVICAL SPINE
Eurostile
A
B
Figure 8–3
One-month postoperative lateral x-ray (A) and
CT (B).
collar is used instead of a Philadelphia collar. Five weeks postoperatively,
the soft collar is removed. Early muscle exercise is recommended to maintain the range of motion (ROM) of the neck. Postoperative stiffness in the
neck and the shoulder resolves within 12 months by degree.
Suggested Readings
Kurokawa T, Tsuyama N, et al. Enlargement of spinal canal by the sagittal
splitting of the spinous process [in Japanese]. Bessat a Sei Kei Geka
1982;2:234–240.
Nakano K, Harata S, Suetsuna F, Araki T, Itoh J. Spinous process-splitting
laminoplasty using hydroxyapatite spinous process spacer. Spine
1992;17(suppl 3):S41–S43.
Eurostile
8 CERVICAL LAMINOPLASTY
43
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9
Posterior Cervical Laminectomy and Fusion
J. Paul Elliott and Anthony P. Dwyer
Goals of Surgical Treatment
To decompress the cervical spinal cord and nerve roots and provide effective instrumentation and fusion of the spine when it is unstable.
Diagnosis
Accurate diagnosis depends on correlation of the salient clinical history,
directed physical examination, diagnostic radiographic studies, and selective electrophysiologic evaluation.
Radiographic Evaluation
Minimal radiographic evaluation should include axial and sagittal cervical
magnetic resonance imaging (MRI) scans, and flexion and extension radiographs. The MRI facilitates assessment of global spinal alignment, identification of the level of anatomic stenosis, detection of the presence of abnormal cervical spinal cord signal, and assessment of nerve root compression
secondary to foraminal stenosis. The MRI evaluation should include axial
cuts throughout the entire cervical spine. Flexion-extension x-rays should
be performed when the patient is minimally symptomatic or following
adequate analgesia to allow for maximal range of motion. The patient
should be assessed for abnormal movement with attention to cervical body
translation, change in canal diameter, and facet and interspinous
widening. Flexion-extension x-rays should be done with caution if gross
instability is suspected or there has been recent trauma.
Radiographic studies facilitate identification of (1) levels of cervical
cord compression, (2) levels of foraminal stenosis, and (3) presence of instability with flexion or extension. Levels of cord compression consistent
with myelopathy and foramina stenosis consistent with radiculopathy
should be correlated with clinical diagnosis based on history and physical
examination.
Indications for Surgery
There are both absolute and relative indications for posterior decompression with or without fusion.
1. Progressive symptomatic cervical myelopathy requires surgical
decompression.
2. The levels of involvement, degree of anterior versus posterior compres-
sion, and degree of maintenance of normal cervical lordosis determine
whether a posterior (laminectomy) or anterior (multilevel discectomy/
fusion or corpectomy/reconstruction) approach should be used.
3. Generally, posterior decompression using laminectomy and
foraminotomies is used for focal or multilevel compression where
there is maintained cervical lordosis. Instrumentation and fusion is reserved for cases where instability is demonstrated on preoperative
flexion-extension cervical spine radiography or when adequate
decompression requires stabilization of the posterior spinal elements.
Contraindications for Surgery
1. Cervical kyphosis.
2. Significant loss of lordosis or primarily anterior spinal cord compres-
sion.
3. In cases of posterior compression with loss of lordosis or kyphosis,
decompression without stabilization should usually be avoided.
Advantages
1. Posterior decompression is a rapid, safe, and efficacious procedure in
experienced hands.
2. Iatrogenic destabilization is rare if the facet joints are preserved.
3. When needed, instrumentation with lateral mass screws and plates
provides immediate and effective stabilization until fusion is
achieved.
Disadvantages
1. Compared to anterior cervical surgery, there is increased perioperative
pain, with an extended recovery time.
2. There is a risk of delayed swan-neck deformity following posterior
decompression without fusion.
Surgical Procedure
Surgical Positioning (Fig. 9–1)
With the patient supine on the hospital gurney, intubation is performed
and appropriate lines, Foley catheter, and compression stockings are
placed. The Mayfield tongs are then tightened to 60 lbs pressure with
points in the thick frontal, parietal, and occipital bone. It is important that
neither the nose nor the ears touch the Mayfield. With adequate personnel,
the patient is then log-rolled to the prone position onto chest rolls or a spinal frame. A sheet is placed slack over the chest rolls or spinal frame to be
used in securing the arms to the sides. When turning the patient, the surgeon should directly grasp the head, avoiding the tendency to turn the
patient while holding onto the Mayfield. The anesthesiologist should control the airway. Once in position, the Mayfield is secured to the bed (the
head of the bed has been removed). Knees are gently flexed and pillows are
placed under the legs. All areas are checked and well padded. In women,
breasts are positioned medially between the chest rolls. Finally, the
desired position of the neck is adjusted for flexion/extension and confirmed radiographically. Tape extending from the shoulders to the bottom
of the bed, under gentle pressure, may aid visualization of the lower cervical spine.
Skin Incision and Exposure
The skin and soft tissues are incised with a knife and hemostasis achieved
with electrocautery after local anesthetic with epinephrine is infiltrated. It
is important to preserve the interspinous ligaments at segments where
laminectomy will not be performed. If instrumentation with lateral mass
screws and plates will be performed, the entire lateral mass should be exposed. Facet capsules at levels that will not be fused should be carefully
preserved.
Spinal Cord Decompression
In cases where lateral mass screws will be used for instrumentation, screw
holes are placed prior to disturbance of anatomic landmarks as delineated
below. Cervical laminectomy is performed at the indicated levels using a
high-speed drill to make lateral trenches at the lateral extent of the canal, in
the valley medial to the facets (Fig. 9–2). We use a Midas-Rex AM-8 bit to
drill through the outer cortical and cancellous bone; the inner cortical surface is removed using a coarse diamond drill bit with irrigation to prevent
thermal injury. The interspinous ligament at the rostral and caudal extent
of the decompression is cut. An up-angled curet is then used in combination with a Kocher clamp on the posterior spinous processes to gently lift
off the free posterior elements one level at a time. This method avoids
placement of instruments such the Kerrison punch under the lamina
where there is significant cervical spinal cord compression and thus
avoids potential spinal cord injury. Finally, the ligamentum flavum is removed from the epidural space and the appropriate drill bit can be used in
combination with a small Kerrison or curet to complete lateral decompression.
Nerve Root Decompression
Nerve roots requiring decompression are identified at their appropriate
facet joints. A combination of high-speed drill, curets, and small Kerrison
punch are used to undercut the medial aspect of facet joint. Adequate root
decompression is ensured with a blunt hook. It is important to maintain
the dorsal surface of the facet joint and capsule to avoid iatrogenic instability. In cases where fusion of the involved level is planned, more bone removal is possible during foraminotomies.
Instrumentation
Placement of screw trajectories prior to decompression maintains familiar
landmarks and eases attainment of correct trajectories. Bleeding is controlled with a small amount of bone wax over each hole until the decompression is complete and screws are placed. Satisfactory placement of the
lateral mass screws is confirmed with an intraoperative radiograph. In the
case of C1-C2 transarticular screws, starting points should also be defined
prior to decompression. Screws should be placed following drilling of
screw trajectories using intraoperative fluoroscopy or navigation. C2 and
C7 pedicle screws are also placed with intraoperative fluoroscopy.
Fusion
Facets of the segments to be fused are drilled to remove joint material.
Lateral mass bone is then decorticated with the high-speed cutting bur and
irrigation, being careful not to create a thermal bone injury that will inhibit
fusion. Morselized autograft harvested from the posterior iliac crest is
packed into the decorticated facet joints and placed along the decorticated
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44
SECTION I THE CERVICAL SPINE
Eurostile
Pillow
under leg
Knees
flexed
Tongs
Figure 9–1
Patient position.
Sheet
holding
arms
Chest
rolls
Expose cervical spine
Holes for
lateral
mass screws
Figure 9–2
(A,B) Normal cervical anatomy: surgical exposure (A), and line for Midas drill trench medial to the facet
joints (B).
Eurostile
9 POSTERIOR CERVICAL LAMINECTOMY AND FUSION
A
B
45
■
lateral mass bone. Alternatively, local autograft from the cervical decompression with or without demineralized bone matrix may also be used.
This usually provides good arthrodesis and avoids the pain and potential
complications at the posterior iliac crest harvest site. In patients at high
risk for pseudarthroses, posterior iliac crest graft should be used, and postoperative use of a bone growth stimulator should be considered.
Alternative Fusion Techniques
Spinous Process Wiring with Structural Autograft
In cases of instability where decompression is not necessary, we may employ soft titanium cables in conjunction with structural autograft. A drill is
used to pierce the cortical bone bilaterally at the base of the spinous
process with completion of the tract using a sharp towel clip. It is important to place this tract at the extreme base of the spinous process and avoid
entering the canal.
Rectangular-shaped structural autograft is harvested from the posterior
iliac crest. It is critical to remove a moderately thick bicortical piece of autograft lengthwise along the crest. An oscillating saw can be used to define
the borders to the desired measurement. Holes are drilled at the desired
spacing equal to the interspinous measurement. The allograft is then split
lengthwise with the oscillating saw to give equal structural autograft
pieces of the desired length. Following decortication of the posterior surfaces of lamina, the two free ends of the titanium coils are placed through
the top and bottom holes of the autograft, respectively, and threaded
through the holes at the base of the spinous processes from opposite directions. The free ends are then threaded through the corresponding holes of
the contralateral autograft. Each free cable end is then placed through the
ipsilateral terminal, and tightened and crimped appropriately.
Facet Wiring
Prior to the advent of the lateral mass screw technique (in cases requiring
total laminectomy), each facet was drilled for placement of a flexible wire
to secure an appropriately shaped autograft, and to obtain a lateral fusion.
Pitfalls
1. Posterior cervical decompression without fusion/instrumentation in
patients with a straight spine or kyphosis increases the likelihood of
postoperative progressive instability.
2. Iatrogenic destabilization from excessive lateral bone removal and
facet destabilization
3. Inadequate attention to cervical root decompression results in failure
to relieve radicular pain. In cases of fusion/instrumentation, failure to
confirm foraminal decompression may result in new postoperative
radicular complaints.
4. Failure to preserve facet joint capsules and interspinous ligaments ros-
tral and caudal to a fused segment may result in iatrogenic instability
at these locations.
5. Following hemostasis at posterior iliac crest autograft harvest site,
minimal foreign body (Gelfoam or bone wax) should remain so as to
decrease the infection rate.
Complications
1. Iatrogenic destabilization in cervical decompression without fusion is
avoided by correct placement of the lateral extent of decompression
and maintenance of the dorsal facets and capsules with limited medial
undercutting during foraminotomies.
2. Aberrant placement of transarticular screws, pedicle screws, and
lateral mass screws with their potential for associated vascular injury
is avoided by using accepted technical guidelines in conjunction with
close inspection of fine-cut computed tomography (CT) with coronal
and sagittal reformats.
3. Sagittal reformats are especially critical prior to placement of transarticular screws, as a significant minority of patients have vertebral
artery anatomy that precludes screw placement, necessitating a Gallie
fusion or equivalent. Use of navigational equipment should be considered when available.
Postoperative Management
Postoperative Cervical Decompression
1. Dressing for 48 hours
2. Semirigid collar for comfort (10 weeks if fusion is performed)
3. Pain medication
4. Anteroposterior (AP) and lateral postoperative radiographs prior to
discharge
5. Discharge on postoperative day 1 or 2 depending on pain control and
age
6. Flexion-extension radiograph when pain-free if no fusion, after 10
weeks if fusion
7. Physical therapy when pain-free (after 10 weeks if fusion)
Suggested Readings
Fields MJ, Hoshijima K, Feng AH, Richardson WJ, Myers BS. A biome-
chanical, radiologic, and clinical comparison of outcome after multilevel cervical laminectomy or laminoplasty in the rabbit. Spine
2000;25:2925–2931.
Guigui P, Benoist M, Deburge A. Spinal deformity and instability after mul-
tilevel cervical laminectomy for spondylotic myelopathy. Spine
1998;23:440–447.
Hamanishi C, Tanaka S. Bilateral multilevel laminectomy with or without
posterolateral fusion for cervical spondylotic myelopathy: relationship to type of onset and time until operation. J Neurosurg
1996;85:447–451.
Huckell CB. Clinical outcomes after cervical spine fusion. Orthop Clin
North Am 1998;29:787–799.
Lee TT, Manzano GR, Green BA. Modified open-door cervical expansive
laminoplasty for spondylotic myelopathy: operative technique, outcome, and predictors for gait improvement. J Neurosurg 1997;86:64–
68.
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46
SECTION I THE CERVICAL SPINE
Eurostile
10
Open Door Laminoplasty for the Treatment of Cervical Spondylolytic Myelopathy
Joseph Riina and David G. Schwartz
Goals of Surgical Treatment
1. Decompression of multilevel cervical spinal stenosis
2. Maintenance of cervical stability after decompression
Diagnosis
Diagnostic tests include anteroposterior (AP), lateral, flexion, and extension radiographs, magnetic resonance imaging (MRI), and computed tomography (CT)/myelogram. Physical findings include difficulty with gait
and long tract signs, including positive Hoffman’s sign, up-going toes with
Babinski, inverted radial reflex, spasticity, difficulty with fine motor activities, decreased sensation, loss of bowel and bladder control, hyporeflexia at the level of compression, hyperreflexia below the lesion, and
clonus.
Indications for Surgery
1. Cervical canal compression extending over three or more levels
2. Neutral or lordotic cervical spine
3. Opacification of posterior longitudinal ligament
Contraindications
1. Cervical kyphosis, which does not allow the spinal cord to shift posteriorly and adequately decompress
2. Cervical instability as defined by translation of more than 3 mm from
flexion to extension; or increased angular motion
Advantages of Open Door Laminoplasty
1. Decreased surgical morbidity, few complications, no need for rigid internal fixation or rigid postoperative immobilization
2. Maintains spinous processes and laminae, which provide protection
and stability
3. Retention of the ligamentum flavum, which acts as a tension band increasing stability
4. Short operative time with minimal blood loss
5. Improved postoperative imaging because of less hardware
6. No risk of pseudarthrosis or graft dislodgment
7. No risk of injury to the esophagus, trachea, or recurrent laryngeal nerve
Disadvantages of Open Door Laminoplasty
1. Unable to use in kyphotic spine
2. Approach more painful postoperatively
Advantages of Multilevel Laminectomy
1. Wide decompression
2. Able to image cervical spine postoperatively
Disadvantages of Multilevel Laminectomy
Rotational instability that presents as cervical kyphosis, swan neck deformity, or multilevel subluxation (usually occurs within 8 months to 2
years).
Advantages of Multilevel Corpectomy
1. Direct decompression including discs, osteophytes, and bone spurs
2. Less postoperative pain
Disadvantages of Multilevel Corpectomy
1. Risk of dural injury when removing large bony osteophytes, or ossification of the posterior longitudinal ligament (OPLL)
2. Need for rigid internal fixation
3. Decreased fusion rates for multilevel corpectomy
4. Increased complication rate, including injury to the esophagus, trachea, and recurrent laryngeal nerve, and swallowing difficulty
5. Graft dislodgment
Open Door Laminoplasty Procedure
Preoperative Planning
1. Choice of levels: MRI for soft tissue evaluation (beware: MRI has the
tendency to overcall the amount of stenosis). CT scan/myelogram for
more accurate bony stenosis evaluation. All levels of compression
should be addressed, and decompression should include the normal
level above and the normal level below.
2. Choice of side of hinge: The open side of the door should be on the side
with the most severe compression (single level or most levels) and/or
the side with radicular symptoms.
Patient Setup
1. Monitoring: Preoperative and intraoperative somatosensory evoked
potentials (SSEP)
2. Decadron: 8 mg Decadron preoperatively
3. Fiberoptic intubation
4. Three-pin Mayfield head rest
5. Wilson frame arms at patient’s side, bed in reverse Trendelenburg position with the patient’s knees flexed to prevent caudal migration, and
the neck slightly flexed
6. Avoid neck extension
Incision
Midline posterior incision from C2-C7/T1 through the ligamentum nuchae
(leave the muscular attachments to C2). Bifid spinous processes will be encountered; care should be taken when dissecting these because they may
be incomplete in the midline with unprotected dura. Subperiosteal dissection should continue along the lamina to the edge of the facet capsule. The
facet capsule should be exposed but not violated. Maintain the muscular
attachments to C2 to increase stability. The intraspinal and supraspinal
ligaments should be resected but the ligamentum flavum must be kept intact. Excise bone from the C6-C7 spinous process, and any spinous process
that will interfere with opening the door should be resected and saved as
local bone graft for the hinge side fusion (Fig. 10–1).
Exposure Secrets
1. Dissect in a cranial to caudal direction. This prevents drainage from
obscuring visualization.
2. Maintain muscular attachments to C2.
Bone Cuts
1. Location
a. The “open” side is at the junction of the facets and laminae.
b. The hinge side is just medial to the junction of the facet and the
laminae.
2. Technique: The groove on the hinge side is made through the outer cortex and the cancellous bone with a Midas AM8 burr. A groove is made
on the open side in the posterior cortex (unicortically) and then
completed with a 1-mm Kerrison punch or 6-0 cervical curet. Unlike in
other techniques, the ligamentum flavum is preserved at the superior
and inferior aspects of the door. This is to increase stability of the construct (Fig. 10–2).
Pearls
1. Maintain flavum superiorly and inferiorly to increase the stability of
the final construct. If needed to open laminoplasty, partial resection
may be performed using a No. 12 blade.
2. Perform foraminotomies prior to cutting grooves on hinge side so they
are adequately decompressed.
3. The hinge side groove is made first. This will maintain an intact
lamina if the groove is made too deeply.
4. To minimize blood loss and maximize visual field, work in a cranial to
caudal direction. Use Gelfoam and bone wax on bleeding cancellous
bone.
5. When tying sutures around spinous process and facet capsules, use a
sliding knot that will allow sequential tightening of the sutures. This
enables the optimum position of the open door to be obtained.
Opening the Door
A Penfield, Woodson elevator, or nerve hook is then used to gently separate
the flavum and the dura, as gentle thumb pressure is applied to the spinous
process toward the hinge. If the door does not readily open, check the su-
Eurostile
10 OPEN DOOR LAMINOPLASTY
47
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Towel clip
Resect
ligamentum
flavum
Gentle
traction
upward
C3
C4
C5
C6
C7
Trough
Complete
Thinned
Rongeur
R
B
line, use
burr
then
rongeur
A
Trough
line, thin
R
L
Figure 10–1
Exposure of the surgical spine from C2-T1. (A) Trough line made with a burr first.
(B) Trough line finished with a rongeur.
R
Open
door
C4
Screw
Eyelet
Suture
A
Figure 10–2
Cervical vertebra depicting groove and suture placement. (A) Axial cross section. (B) Posterior view.
■
48
SECTION I THE CERVICAL SPINE
Eurostile
B
Compressed
cord
Cord
stenosis
A
Anterior cervical body
Anterior cervical body
Facet
joint
Open
door
B
Open door
Spinous
process
Spinous
process
Facet
joint
Eyelet
Suture
Figure 10–3
Cervical stenosis C4–5, C5–6, and C6–7. (A) Preoperative axial magnetic resonance imaging (MRI) of C4–5. (B) Postoperative axial MRI of C4–5. (C) Preoperative sagittal
MRI demonstrating multilevel stenosis. (D) Postoperative sagittal MRI demonstrating decompression of the spinal cord.
Screw
Eurostile
10 OPEN DOOR LAMINOPLASTY
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