Degenerative Spine Flashcards
- A 56-year-old female presents with neck pain worsened by activity over the last 6 months.
On examination, she has full power bilaterally in the upper and lower extremities. She has a normal gait and no difficulties with manual dexterity. Which one of the following is the most appropriate next step in management?
a. Posterior laminectomy C5-C7
b. Physiotherapy
c. Cervical epidural injection
d. C5/C6 ACDF
e. C5/C6 foraminotomy
b. Physiotherapy
Cervical spondylosis is characterized by degeneration of the disc, both facet joints and both uncovertebral joints of the cervical motion segment most commonly at C5/6 and C6/7 levels where the majority of flexion/extension occurs. Risk factors include age (5th decade onwards), males, excessive driving, smoking, lifting, and professional athletes (e.g. jockeys, rugby, gymnastics). It involves disc
degeneration (loss of height, bulging, and herniation), joint degeneration (uncinate spurring, facet hypertrophy), ligamentous changes (thickening infolding, bowstringing), and kyphosis. Presentation is usually with discogenic neck pain, radiculopathy or myelopathy. Nerve root compression may be due to foraminal stenosis due to spondylotic changes (e.g. chondrosseous spurs of facet and uncovertebral joints), posterolateral disc herniation or disc-osteophyte complex in the lateral recess, and foraminal soft disc herniation. Cervical cord compression due to central canal stenosis leads to a clinical picture of myelopathy and occurs with a canal diameter <13 mm (normal is 17 mm), worse during neck extension when the central cordbecomes pinched between degenerative disc (anteriorly) hypertrophic facets and infolded ligamentum (posteriorly). X-rays may show degenerative changes of uncovertebral and facet joints, osteophyte formation, disc space narrowing, vertebral endplate sclerosis, sagittal canal diameter <13 mm and spondylolisthesis but often do not correlate with symptoms (70% of patients by 70 years of age will have degenerative changes).
Flexion and extension views should be assessed
for instability and compensatory subluxation above or below the spondylotic segment, and oblique views for foraminal stenosis. MRI can assess status of soft tissues and identifies neural compression (CT myelography in patients that cannot have an MRI). Nerve conduction studies may help in cases where clinical and imaging findings are unable to distinguish between central versus peripheral causes. Management in initially nonoperative (physiotherapy, NSAIDs, and a cervical collar) but can be escalated if this fails or the patient develops radiculopathy/myelopathy (e.g. foraminotomy, laminectomy, anterior cervical
discectomy).
Which one of the following statements
regarding nonoperative management of cervical disc and degenerative disorders is most accurate?
a. Nonsteroidal anti-inflammatories should be avoided
b. Neck pain related to cervical spondylosis improves in only one third of patients
c. Cervical traction systems are generally
recommended
d. Use of soft cervical collars should not
exceed 3 months
e. Cervical epidural injections are more effective in those with neck pain and radiculopathy
e. Cervical epidural injections are more effective in those with neck pain and radiculopathy
Many cases of acute neck pain may arise from soft
tissue sprains and muscle strains, but ongoing
neck pain is more suggestive of a spondylotic
source. The natural histories of most nonmyelopathic spondylotic cervical disorders are statistically favorable, with 40-50% becoming pain
free/no recurrence and 20-30% getting worse/
persisting (i.e. 70-80% improve to varying
degree). Modifiable factors have been identified,
including smoking, obesity, occupational hazards,
and psychological factors. Initial treatment of
acute pain can include a brief trial of rest and
immobilization with a soft cervical collar. Medications including narcotics, NSAIDs, oral steroids, and antidepressants can be beneficial.
Although short-term (<2 weeks) use of cervical
collars may be beneficial, prolonged immobilization should be avoided to prevent atrophy of the cervical musculature. Traction (at home) should be avoided in myelopathic patients to prevent stretching of a compromised spinal cord. Participation in an active rehabilitation protocol seems much more likely to be successful than use of passive modalities. Cervical manipulation should not be undertaken without an adequate radiographic examination to screen for potential instability, given complications that include radiculopathy, myelopathy, spinal cord injury, and vertebrobasilar artery injury. Cervical epidural injections, or selective root blocks, help most in those with neck pain and radiculopathy but it is unclear whether they alter the natural history of radiculopathy or surgical management. Complications of cervical steroid injections are rare but devastating when they occur (dural puncture, meningitis, epidural abscess, intraocular hemorrhage, adrenocortical suppression, and epidural hematoma).
Patients with myelopathy, severe or progressive
neurologic symptoms, or failure to improve with
time are good candidates for surgery whereas
those with axial neck pain alone from disc degeneration are not.
A 41-year-old male presents with left arm pain of 4 weeks duration. On examination there is weakness of triceps and wrist flexion. Axial MRI is shown. Which level is the pathology shown likely to be at?
a. C4/5
b. C5/6
c. C6/7
d. C7/T1
e. T1/T2
c. C6/7
Pedicle/nerve root mismatch between cervical
and thoracolumbar spine is that in the cervical
spine a given nerve root exits above the pedicle
belonging to its named vertebra (e.g. C6 nerve
root exits at the C5/6 intervertebral foramen).
However, since C8 nerve root exits at C7/T1 level below this all names nerve roots exit below the
pedicle of its named vertebrae (e.g. L5 nerve root
exits at L5/S1 intervertebral foramen). As such,
nerve roots in the cervical spine have a horizontal
path whereas those in the lumbar spine are more
vertically orientated. This is important, because of
the resultant differential effect of posterolateral
and foraminal disc herniations in the lumbar spine
but not the cervical spine. For example, in the cervical spine at C5/6 either a posterolateral disc herniation or a foraminal disc herniation will cause a C6 radiculopathy. In contrast, in the lumbar spine
at L4/5 a posterolateral disc herniation will affect
the traversing nerve root (i.e. L5 nerve root) while
foraminal disc will affect the exiting L4 nerve root.
Central disc prolapses in the cervical or thoracic
spine will result in myelopathy if significant,
whereas in the thoracolumbar (T12-L2) and
lower lumbar spine they may cause conus medullaris syndrome (mixture of UMN/LMN signs and bladder involvement) or cauda equina syndrome respectively. Common patterns of radiculopathy in the cervical spine include:
C5 radiculopathy leads to deltoid and biceps
weakness, C6 radiculopathy leads to brachioradialis and wrist extension weakness,
C7 radiculopathy leads to triceps and wrist
flexion weakness, and
C8 radiculopathy leads to finger flexion
weakness.
Which one of the following statements
regarding radiculopathy is most accurate?
a. Hoffman’s sign is suggestive of C5
radiculopathy
b. Spurling’s test involves rotation, extension and axial compression applied to the cervical spine
c. Cervical foraminotomy is indicated in
radiculopathy secondary to posterolateral disc protrusion
d. ACDF is not appropriate for patients presenting with radiculopathy and neck
pain alone
e. Shoulder abduction test is positive if radiculopathic pain worsens
b. Spurling’s test involves rotation, extension and axial compression applied to the cervical spine
Incidence of cervical radiculopathy was found to
be 83 per 100,000 population, with a peak incidence in the 6th decade of life. While central disc prolapses can cause myelopathy in cervical/thoracic spine, or conus medullaris/cauda equina syndromes in the lumbar spine. While in the lumbar spine posterolateral disc prolapse causes a radiculopathy affecting the traversing nerve root and far lateral/foraminal disc prolapses affect the exiting nerve root, both types of disc herniation affect the same nerve root in the cervical spine (as travel horizontally). The two major provocative tests for cervical radiculopathy include the Spurling test and the shoulder abduction test.
They state that acute cervical radiculopathy has
75% rate of spontaneous improvement with nonsurgical treatment. If surgery is necessary, either anterior cervical discectomy and fusion (ACDF) or posterior laminoforaminotomy is warranted Posterior cervical foraminotomy is highly effective in treating patients with cervical radiculopathy. The approach is effective in decompressing
lateral spinal roots that are compromised by soft
disc herniations or osteophytic spurs. It also
reduces the risk of iatrogenic injury with anterior
approaches. Long-term radiographic follow-up
shows no significant trend toward kyphosis and
improved long-term pain scores compared to
nonoperative treatment. Advantages of ACDF
include increased fusion rates (with graft insertion in the disc space) and decompression of the
neural foramina by increasing its cephalocaudal
dimension. On the other hand, the posterior
approach maintains spinal alignment and does
not require fusion, but increases risk of neck pain
(from posterior muscle dissection).
A 65-year-old male presents to your office with difficulty ambulating and buttoning his shirt. It started 2 years ago but has worsened significantly over the last year. On examination he is unable to perform a tandem gait and is Hoffman’s sign positive bilaterally, but has flexor plantar reflexes bilaterally. He has 4/5 power in his hands, but 5/5 power in all other muscle groups. MRI sequences are shown. Which one of the following is the most appropriate next step in management?
a. C5/6 ACDF
b. C5/6 and C6/7 ACDF
c. C6 corpectomy
d. C5-C6 laminectomy
e. C5-C6 laminectomy and instrumented
fusion
a. C5/6 ACDF
The incidence of cervical myelopathy is difficult
to ascertain due to subtly of early findings and
overlap with features of “old age.” The natural
history of spondylotic cervical myelopathy is
characterized by slow progression in a pattern
of stepwise deterioration following periods of stable symptoms. Patients often complain of balance issues, numbness and weakness in their hands, and difficulty with fine motor tasks. Examination may reveal Hoffman’s sign and finger escape sign in a myelopathic hand, and long tract signs in the legs (e.g. clonus, extensor plantar response), and difficulty with tandem gait. Factors that are associated with worse outcomes with nonoperative treatment include segmental kyphosis and circumferential spinal cord compression. Clinical classification systems for cervical myelopathy include Nurick, Ranawat, and the Japanese Orthopaedic Association. Imaging shows loss of the CSF signal around the cord, and intramedullary hyperintensity on T2 weighted imaging.
Sometimes myelopathy may be due to dynamic
cord compression, still producing high T2 signal
in the cord, without cord compression in the neutral position hence flexion extension X-rays or
dynamic imaging may be required. In this case,
there is extrusion of the C5/6 disc with migration
caudally and ACDF at this level is indicated
A 55-year-old man presents to your office ith difficulty ambulating and buttoning is shirt. It started 2 years ago but has worsened significantly over the last year. On physical exam he is unable to perform a tandem ait and has a positive Hoffman’s sign bilaterally, however he has no ankle clonus and
flexor plantars bilaterally. He has 4/5
strength in his hands, but 5/5 strength in
all other muscle groups. Sagittal MRI is
shown. Which one of the following is the
most appropriate next step in management?
a. C3-C6 laminectomy with lateral mass screw fixation
b. C3-C6 ACDF without instrumentation
c. Cervical epidural steroid injection
d. C3-C6 laminectomy
e. C3-C6 bilateral foraminotomies
a. C3-C6 laminectomy with lateral mass screw fixation
This patient has cervical myelopathy with multilevel anterior and posterior compression. Presence of a rigid kyphotic deformity favors use of an anterior approach (can correct kyphotic deformity as well as decompress cord; posterior surgery is unable to correct deformity and may make it worse if noninstrumented). Posterior laminectomy and instrumented fusion is preferable for patients with a lordotic cervical spine and either three or more levels of compression, primarily posterior compression or diffuse congenital stenosis.
A 68-year-old female presents with progressive loss of ability to ambulate and dexterity problems with her hands. Six months ago she was able to walk with a cane, but now has difficulty with ambulating with a walker.
She also reports difficulty with her hands and needs assistance with eating. Physical exam shows limited neck extension. Flexion extension X-rays do not show any dynamic instability. MRI is shown. Which one of the following is the most appropriate next step in management?
a. C5-C6 posterior decompression and
instrumented fusion
b. Physiotherapy and NSAIDs
c. C5-C6 laminoplasty
d. C5-C6 decompressive laminectomy
e. C5/6 and C6/7 anterior cervical decompression and fusion with anterior plate fixation
e. C5/6 and C6/7 anterior cervical decompression and fusion with anterior plate fixation
In patients with cervical myelopathy due to canal
stenosis, surgical approach will be influenced by
the sagittal alignment of the cervical spine. Lateral cervical radiographs in neutral position and
flexion and extension can identify kyphotic deformity and determine whether it is rigid or not. The C2-C7 angle is determined by intersecting lines
extended from the posterior borders of the C2
and C7 vertebral bodies respectively, whereas
the local kyphotic angle is based on the posterior
borders of the vertebral bodies that immediately
flank the kyphotic segment. If patients have significant kyphosis, the spinal cord is draped over
the anterior compressive elements, and a posterior approach alone is not recommended. The
mainstay of treatment in most patients with
multi-level disease would be laminectomy with
posterior fusion or laminoplasty (if kyphosis is
<10-13°) or a combined anterior and posterior
approach (if kyphosis is >10-13°). Possible treatment options in this case could be (1) C5/6 and C6/7 anterior cervical decompression and fusion with anterior plate fixation, (2) C5 corpectomy with ACDF at C5/6 and anterior plate fixation, or (3) a C5 and C6 corpectomy, anterior plate fixation, followed by posterior decompression and instrumented fusion (any two level corpectomy needs to be stabilized posterior due to the high rate of graft migration).
A 44-year-old presents with worsening gait and loss of fine motor control in his hands.
Examination reveals normal cranial nerve examination, negative jaw jerk, hyperreflexia in all four limbs, positive bilateral Hoffman’s signs and Babinski positive. There is no evidence of dynamic instability on flexion/ extension radiographs. MRI shown below.
Which one of the following is the most
appropriate next step in management?
a. C3-C6 laminectomy
b. C3-C6 unilateral foraminotomy
c. C3-C6 bilateral foraminotomy
d. C3-C6 anterior cervical decompression
e. C3-C6 microdiscectomy
a. C3-C6 laminectomy
This case shows cervica myelopathy due to canal
stenosis at multiple levels without any kyphotic
deformity. In this situation, the goal is decompression of the spinal cord which will only be adequate with laminectomy. Pre-operative flexion/extension films should be performed as if any evidence of instability this may favor instrumented fixation with lateralmass screws. Intraoperative concerns include
maintaining MAP >70 mmHg in myelopathic
patients, avoiding dural tears, ensuring sufficient
width of the laminectomy (approx. 15 mm), avoiding violation of the facet joints (<50%) and minimizing risk factors for C5 palsy.
A 42-year-old with a 3-month history of
shooting pains down his left arm which is
still severe 7/10 and not improved with
physiotherapy or epidural steroid injection.
On examination, Spurling’s sign is positive (left side), left wrist extensor weakness 4+/5, decreased sensation to pinprick in left C6 distribution. No hyperreflexia or Babinski sign. Cervical MRI shown below. Flexion/extension views do not show any evidence of instability. Which one of the
following is the most appropriate next step in management?
a. Posterior foraminotomy
b. Anterior cervical decompression
c. C6 laminectomy
d. C6 arthroplasty
e. C6 laminectomy and C5-C7 instrumented fusion
a. Posterior foraminotomy
The case describes a left C6 radiculopathy which
has failed conservative management, and MRI
shows foraminal stenosis. As such posterior
foraminotomy is the most appropriate first line
operative treatment. The goal is to open the
intervertebral foramen to decompress exiting
nerve root, which can be done unilaterally or
bilaterally at one or more levels for patients with
radiculopathy. Care must be taken to avoid
resecting over 50% of the facet otherwise this
could lead to instability. The other choices are
indicated when myelopathy is present due to
canal stenosis/disc herniation
A 55-year-old presents with 4 months of gait impairment and sustains a fall. On examination, there is spastic tetraparesis 4-/5 globally without evidence of any cerebellar signs. MRI cervical spine is shown. Which one of the following is the most appropriate next step in management?
a. C3-C7 laminectomy
b. C3-C7 laminoplasty
c. C3/4, C4/5.C5/6, and C6/7 ACDF
d. C3-C5 corpectomy, srut graft, plates
and screws
e. C3-C6 corpectomy, srut graft, plates
and screws with resection of posterior
longitudinal ligament
b. C3-C7 laminoplasty
OPLL is a common cause of cervical myelopathy
in the Asian population, men >women, C4-C6
levels Risk factors diabetes obesity high salt-low
meat diet poor calcium absorption mechanical
stress on posterior longitudinal ligament. Presentation may be with myelopathy, neck pain or
asymptomatic. Lateral radiographs often shows
ossification of PLL important to evaluate sagittal
alignment of cervical spine. MRI is study of choice
to evaluate spinal cord compression, whereas CT
will delineate bony anatomy of ossified posterior
longitudinal ligament. Given the propensity for
progression, nonoperative management may only
be indicated in those with mild symptoms and/or
who are not candidates for surgery. Most symptomatic patients will undergo surgery, with anterior or posterior approaches. Anterior approaches may involves interbody fusion (limiting changes in sagittal canal diameter with flexion/extension hence best for dynamic myelopathy) or corpectomy with/without resection of the OPLL (can just be left to float in corpectomy site, and reduces risk of dural tear when trying to dissect PLL off thecal sac) and must be used in those with existing kyphotic deformity. Posterior laminoplasty or laminectomy with fusion is only appropriate in lordotic cervical spine and is safer and preferable approach due to the difficulty of resecting the OPLL off the dura from an anterior approach. Where laminectomy (rather than laminoplasty) is performed instrumented fusion to avoid postoperative kyphosis is recommended.
Postoperatively following C3/4 ACDF a
patient notices decreased sweating on one side of her face and slight eyelid droop on the same side. Which one of the following is most likely?
a. Retraction injury to vagus nerve in carotid sheath
b. Intraoperative stroke due to disruption of carotid plaque
c. Injury to sympathetic chain along longus colli muscle
d. Traction injury to cutaneous cervical sensory nerves giving reduced sensation of sweating
e. Thermal injury to branches of facial nerve within the parotid gland
c. Injury to sympathetic chain along longus colli muscle
Which one of the following have been associated with reduced risk of recurrent laryngeal nerve palsy?
a. Left sided neck dissection
b. Deflating ETT pressure after retractor
insertion
c. Same side approach for revision surgery
d. Sharp dissection during exposure
e. Anterior cervical plate fixation
a. Left sided neck dissection
Right recurrent laryngeal nerve ascends in the
neck after passing around the subclavian vessels,
courses medially and cranially at the C6-C7 level,
often along with the inferior thyroid artery. In
contrast, the left recurrent laryngeal nerve curves
around the aortic arch and then ascends along the
tracheoesophageal groove in a more midline and
protected position. This has led some to suggest a
left-sided approach is safer especially when lower
cervical segments are approached, but studies
favoring either a right- or a left-sided approach
are found in the literature. Arguments supporting
a left-sided approach have been based on anatomical factors described and the possible occurrence of a nonrecurrent inferior laryngeal nerve on the right, while proponents of a right-sided approach have argued that it is more comfortable for righthanded surgeons, that a left-sided approach puts the thoracic duct at risk (at C7-T1 level), and that the esophagus lies anatomically slightly to the left, which renders a right-sided approach safer.
. A 54-year-old female undergoes an C6/7 ACDF via right sided approach and does not have any new postoperative deficits.
Three days later, she develops burning pain to her left shoulder region followed by loss of shoulder abduction and weakness of elbow flexion. Post-operative MRI of the cervical spine was unremarkable. Which one of the
following is most likely?
a. Cage migration
b. Epidural hematoma
c. Traction injury to brachial plexus from
taping of shoulders
d. Parsonage-Turner syndrome
e. C7 palsy
d. Parsonage-Turner syndrome
The most common nerve injury with anterior and
posterior cervical spine surgery is C5 nerve palsy,
with an incidence of about 5%; decompressive
procedures for myelopathy have the highest rate
of this complication. Several theories potentially
explain nerve root palsies, including direct trauma
or a traction phenomenon from displacement of
the spinal cord after decompression, or segmental
cord gray matter dysfunction. Patients with C5
palsy generally present in a delayed fashion
(within 1 week) postoperatively, sometimes even
as long as 1 month postoperatively. The most
common presentation is with deltoid and biceps
weakness.
Generally, if a patient awakens from surgery
with upper extremity weakness, the differential
should include shoulder traction (diffuse distribution) caused by positioning or intraoperative
nerve trauma (root and side specific). When presenting in a delayed fashion, the main differentials
include compressive causes (cage/bone graft
migration) which can be excluded on MRI, C5
nerve palsy and Parsonage-Turner syndrome
(PTS). PTS is typically characterised by severe
pain followed shortly by the onset of weakness,
and the weakness, sensory deficit, and pain usually do not all correspond to the same nerve root
or peripheral nerve distribution. By contrast, the
C5 palsy is predominantly motor disturbance.
EMG is useful at 1-4 weeks after onset to clarify
distribution. If no compression is noted, patients
are treated symptomatically with physical therapy
and pain control. Given the lack of deltoid function and the possibility of a traction phenomenon,
patients with C5 palsy are given a sling for
comfort (steroids are not routinely given). Most
patients recover within 6 months.
Six hours after a C5-C6 ACDF, the nurse
calls you that the patient is having difficulty swallowing and breathing. By the time you arrive to the bedside, the patient is in distress, SOB, tachycardic, tachypneic, despite being on a nonrebreathe oxygen facemask. The
hemovac drain reservoir showed minimal bloody drainage and the tubing appeared to be clotted and his neck is extremely tense and swollen. She appears cyanosed and SpO2 is 79% and falling. Which one of the following is the most appropriate next step in management?
a. Stat neck X-ray to look for cage migration
b. Urgent neck CT
c. Immediately reopen neck incision at the bedside
d. Intramuscular adrenaline
e. CT pulmonary angiogram
c. Immediately reopen neck incision at the bedside
One of the most serious adverse events associated
with anterior cervical spine surgery is postoperative airway obstruction due to wound hematoma.
The reported incidence of this complication has
varied from 0.2% to 1.9%. Hematoma following
anterior cervical spine surgery may be the result of
inadequate control of arterial or venous bleeding
during the operation, and has been reported due
to superior thyroid artery dissection. In
other instances, a hematoma can form after surgery irrespective of adequate intraoperative
hemostasis. Postoperative hemorrhage may occur
secondary to coagulopathy, increased blood pressure during emergence from anesthesia, or elevated venous pressure due to the Valsalva effect of coughing at the time of extubation. There are two potential pathophysiologic mechanisms by
which hematoma can produce airway compromise. The first is direct mechanical compression
leading to reduction in the cross-sectional area
of the airway lumen. The second mechanism
involves the development of intrinsic airway
edema in response to the mass effect of collected
blood within the surgical wound impaired venous
drainage (more likely as requires lower pressure to
obstruct). Although delayed hematoma is possible
beyond the first 12 h, alternative causes of airway
obstruction (e.g. pharyngeal/prevertebral edema,
spinal construct failure, cerebrospinal fluid collection or retropharyngeal abscess) become more probable. The primary treatment objective is to establish and maintain patency of the airway by
placement of an endotracheal tube—in a noncritical airway this is attempted in the operating suite, whereas in the critical airway compromise (e.g. air hunger, excessive salivation, a rocking motion of the head and chest with the respiratory cycle, use of accessory muscles of respiration, inspiratory stridor and, eventually, central cyanosis) this is done at the bedside. Once definitive airway control is achieved, the patient can undergo wound exploration in theater. However, if the initial intubation attempt fails (or airway management equipment is not immediately available), the surgical wound should be opened and blood clot removed at the bedside followed by reassessment of airway and need for further intubation attempts/cricothyroidotomy
A 52-year-old female underwent a C5/6 ACDF for cervical radiculopathy through a left-sided approach 2 years ago. She has had an altered voice since this operation. Recently, the patient has developed myelopathic symptoms including gait instability and dexterity problems with her hands. Flexion extension X-rays do not reveal any dynamic instability. MRI is shown. Laryngoscopy demonstrates abnormal function of the vocal cords on the left hand side. Which one of the following is the most appropriate next step in management?
a. C3/4 and C4/5 ACDF via right sided
anterior approach
b. C3/4 and C4/5 ACDF via left sided anterior approach
c. C3-C7 laminectomy with instrumented fusion
d. C3-C7 laminoforaminotomy
e. C3-C5 laminoplasty
c. C3-C7 laminectomy with instrumented fusion
Adjacent level disease is a relatively frequent clinical finding after cervical spine surgery (approx.
3%). Whenever possible, nonoperative treatment should be attempted, but it may be less successful than in de novo cervical spondylotic
syndromes. If nonoperative treatment fails, radiculopathy or myelopathy caused by adjacent level disease can be treated operatively much in the same manner as de novo disease. Relevant considerations in the operative treatment of adjacent segment disease include anterior versus posterior approaches, fusion versus motion-preserving procedures, and single-level versus multilevel surgical procedures. Revision ACDF has good outcomes, but suspected pseudoarthrosis at the index level and recurrent laryngeal nerve status should be considered. The right and left recurrent laryngeal nerves innervate the posterior cricoarytenoid muscles which open the vocal cords.
Injury to the ipsilateral recurrent laryngeal nerve
can occur in 1.5-6% of patients after ACDF, with
resultant unilateral paralysis of the posterior cricoarytenoid muscle. Although paralysis of this
muscle unilaterally is usually benign, bilateral
paralysis can lead to severe airway difficulties
and the need for tracheostomy. If revision surgery is planned from the opposite side, the vocal
cords need to be evaluated with laryngoscopy
preoperatively. If there was asymptomatic/occult
(left) RLN injury from the initial surgery, then
the opposite side approach is inadvisable for fear
of developing bilateral vocal cord paralysis and its
catastrophic complications. Posterior decompression and fusion can provide a high fusion rate and avoid revision ACDF at the index level. Patients with multilevel spondylotic compression may also benefit from a posterior approach to address multiple levels of disease. Posteriorly based nonfusion options include laminoforaminotomy for single-level radiculopathic symptoms and laminoplasty for multilevel disease. Contraindications to laminoplasty include cervical
kyphosis, which does not allow the spinal cord
to drift posteriorly and be indirectly decompressed, and significant preoperative neck pain.
The rate of postoperative neck pain after laminoplasty is high, and patients should be counseled accordingly. Given the relatively recent advent of cervical disc arthroplasty, clinical data are currently not sufficient to recommend for or against arthroplasty at a level adjacent to a fusion. This case describes myelopathy with evidence of multilevel disease, both above and below the fused
segment, without any kyphotic deformity, but
in the presence of an occult left recurrent laryngeal nerve palsy. These features favor a posterior
approach from C3 to C7, which could be either
laminoplasty or laminectomy with instrumented
fusion.
A 73-year-old female presents with neck pain and clumsiness in her hands. Past medical history includes rheumatoid arthritis. On exam she has 4 +/5 power in the lower limbs, hyperreflexia and extensor plantars. Flexing her neck produces an electric shock-like sensation down her spine. Which one of the following is the most appropriate next step in management?
a. Rigid collar for 6-12 weeks
b. Halo immobilization for 12 weeks
c. Transoral odontoid resection
d. Anterior odontoid screw fixation
e. Posterior C1-C2 fusion
e. Posterior C1-C2 fusion
Although the occurrence of radiographic evidence of disease as atlantoaxial subluxation in
asymptomatic patients is common, the most frequent presenting symptom is pain. It is usually a
combination of occipital and neck pain that
either is caused by mechanical instability or is
radicular, as a result of compression of C1 and
C2 nerves. A positive Sharp-Purser test is a clicking sensation in extension that results with spontaneous reduction of atlantoaxial subluxation.
Neurologic manifestations are less common
and are caused by mechanical neurovascular
compression on the cervical spine and cervicomedullary junction. Patients may present with cervical myelopathy manifesting as gait dystaxia, hand clumsiness, and difficulty with dexterity.
Objective findings of myelopathy include weakness, hyperreflexia, and positive Hoffmann,
Babinski, and Lhermitte signs. Cruciate paralysis
and even sudden death from respiratory arrest
have also been reported. The deep tendon reflex
may not be elicited in RA because of appendicular joint destruction. Anterior subluxation of the
atlas on the axis results from weakening and disruption of the transverse ligament following
joint inflammation around it. The subluxation
can be anterior, posterior, lateral, or rotatory.
An atlantoaxial subluxation occurs in 60-80%
of cases of rheumatoid arthritis (RA) as the result
of pannus formation at the synovial joints
between the dens and the ring of C1. Patients
with symptomatic instability or no symptoms
but ADI>10 mm and SAC<14 mm are generally managed with operative stabilization. If the
subluxation is reducible, a posterior approach
and C1-C2 instrumented fixation are used. Occipitocervical fusion (O-C2) may be considered in
this patient population if co-existent basilar
invagination is present or likely in future, or if
anterior compression from pannus requires C1
posterior arch resection. When the subluxation
is not reducible or when it is associated with
anterior pannus compressing the upper cervical
spine, anterior release of odontoid is generally
required before posterior fusion.
Which one of the following statements
regarding the condition shown is LEAST
accurate?
a. Transoral odontoid resection may be required in reducible migration
b. Cervicomedullary angle < 135° suggests impeding neurological compromise
c. Occipitocervical (O-C2) fusion is usually
appropriate if deformity reduction if
possible
d. Ranawat C1-C2 index is the most reproducible radiological sign
e. The tip of the dens is >4.5 mm above
McGregor’s line
a. Transoral odontoid resection may be required in reducible migration
With RA progression, the atlanto-occipital and
atlantoaxial joints and lateral masses are
destroyed, resulting in cranial migration of the
odontoid process and hence “settling” and rheumatoid basilar invagination in 40%. This condition leads to variable degrees of neurovascular cervicomedullary compression. Multiplanar CT and MRI studies that delineate the bony and the neurovascular anatomy, respectively, should always be used during the workup because they also facilitate the diagnosis. Surgery is indicated when patients are symptomatic, when radiographic evidence of instability is present, or when the degree of compression of cervicomedullary junction is severe (cervicomedullary angle
<135°). The surgical approach depends on the
ability to achieve reduction preoperatively. Flexion and extension imaging is helpful in determining the extent or absence of reduction. Often,
preoperative traction can also be used in achieving reduction and is successful in 75% or 80%
of the cases. When reduction occurs, dorsal occipitocervical fusion (O-C2), with or without suboccipital decompression, is sufficient. When the
invagination is not reducible, transoral resection
of the odontoid/pannus should precede dorsal
occipitocervical fusion.
A 29-year-old male presents with numbness and tingling in his lower extremities and gait instability for 2 weeks. Physical exam shows 3+ brisk patellar reflexes. MRI is shown. Which one of the following is the LEAST appropriate next step in management?
a. Laminectomy and discectomy
b. Anterior thoracic discectomy
c. Transpedicular approach and discectomy
d. Transcostovertebral approach and
discectomy
e. Costotransversectomy and discectomy
a. Laminectomy and discectomy
The clinical presentation and imaging studies are
consistent with a thoracic disc herniation with
spinal cord compression causing symptoms of
thoracic myelopathy. This is an indication for surgery. Thoracic level disc herniations are treated
with anterior discectomy with or without fusion.
* Thoracic disc herniations, although uncommon, are encountered by spine surgeons.
Relative immobility of the thoracic spine
as compared with the cervical and lumbar
regions and thus the low incidence of degenerative changes. The majority are T8-T11.
* Laminectomy is an unacceptable treatment
for thoracic disc herniations due to high
rates of paralysis and death in the earliest
published studies (1950-1960s). Since the
abandonment of laminectomy for thoracic
disc herniations, morbidity and mortality
rates have dropped significantly.
* Posterior techniques include the transpedicular, Stillerman’s transfacet pedicle sparing,
transcostovertebral, costotransversectomy,
and lateral extracavitary.
* Posterior approaches are generally favored
in cases of more lateral, noncalcified, extradural disc herniations and in those not fit
enough for an anterior approach (e.g. pulmonary disease.
* Anterior approaches include the transthoracic (below T4), retropleural, and transsternal (above T4).
* Anterior techniques offer better ventral
exposure for discs that are centrally located,
calcified, and/or intradural.
* Complication rates for the common posterior and anterior procedures are similar.
