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6. Spine MCQs

Practice Set 110 of 379

This practice set contains high-yield board review questions covering key concepts in 6. Spine. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2181

Topic: 6. Spine
The cervical disk herniation shown in the MRI scans in Figures 30a and 30b will most likely create which of the following constellations of symptoms?
. Right thumb and index finger numbness and triceps weakness
. Right thumb and index finger numbness and wrist extensor weakness
. Right wrist extensor weakness and diminished triceps reflex
. Right middle finger numbness and diminished brachioradialis reflex
. Right little and ring finger numbness and diminished brachioradialis reflex

Correct Answer & Explanation

. Right thumb and index finger numbness and wrist extensor weakness

Explanation

DISCUSSION: The MRI scans reveal a right-sided C5-6 herniated nucleus pulposus. A disk herniation in this region encroaches on the C6 root and is accompanied by a sensory change along the thumb and index finger, alterations in the brachioradialis reflex, and possible wrist extension weakness. Although the nerve root associated with the vertebral body passes above the pedicles such that the C6 root passes above the C6 pedicle, it is still the C6 root that is encroached on because the herniation affects the exiting root rather than the traversing root as seen in the lumbar spine. REFERENCES: Klein JD, Garfin SR: Clinical evaluation of patients with suspected spine problems, in Frymoyer JW (ed): Adult Spine: Principles and Practice, ed 2. Philadelphia, PA, Lippincott-Raven, 1997, pp 319-330. Hoppenfeld S: Orthopaedic Neurology. Philadelphia, PA, JB Lippincott, 1977, pp 7-49.

Question 2182

Topic: 6. Spine
Figures 31a and 31b show the radiograph and MRI scan of an otherwise normal 3-month-old infant who has a spinal deformity. MRI reveals no intraspinal anomalies. What is the next step in management?
. Posterior spinal fusion with instrumentation
. Anterior-posterior hemiepiphysiodesis
. Brace management
. Cardiac and renal evaluation
. Hemivertebrectomy and fusion

Correct Answer & Explanation

. Cardiac and renal evaluation

Explanation

Congenital scoliosis in an infant warrants evaluation of the renal, cardiac, and neurologic systems because frequently there is concurrent pathology. Progression in this instance is possible but not certain; therefore, progression must be documented prior to any surgical intervention. Close observation with serial radiographs every 4 to 6 months is appropriate. All of the surgical options listed may be reasonable choices in the future, but cardiac evaluation is the most important issue at this time.

Question 2183

Topic: 6. Spine
Figure 10 shows the radiograph of an 18-year-old woman who sustained a spinal cord injury in a motor vehicle accident. Based on the radiographic findings, her injury is best described as
. distractive extension.
. compressive extension.
. lateral flexion.
. distractive flexion.
. compressive flexion.

Correct Answer & Explanation

. distractive flexion.

Explanation

The Allen and Ferguson mechanistic classification system is a useful tool for evaluating cervical spine injuries. Cervical fractures are classified as compressive extension, distractive extension, compressive flexion, distractive flexion, vertical compression, and lateral flexion. The patient has a distractive flexion injury.

Question 2184

Topic: 6. Spine

Which of following is pathognomonic of intervertebral disk degeneration? Review Topic

. Increased water content in the nucleus pulposus
. Loss of Type X collagen in the nucleus pulposus
. Decreased thickness of the inner annulus fibers
. Degradation of large proteoglycans molecules in the nucleus pulposus
. Annular tears and fissuring occurring most frequently in the central disc

Correct Answer & Explanation

. Increased water content in the nucleus pulposus

Explanation

Degradation oflarge proteoglycan molecules inthe nucleus pulposus ispathognomonicof intervertebral disk(IVD) degeneration.Degeneration of the intervertebral disk (IVD) is a major pathological process implicated in low back pain and is often considered a prerequisite for intervertebral disc herniation. While the pathophysiologic causes of IVD degeneration at the molecular level are not fully known, there are many physical and molecular changes that are known to contribute to the disease process. The most significant is loss of large proteoglycan molecules and decreased water content.An et al. showed that large proteoglycans (PGs), such as aggrecan and versican, decrease in patients with intervertebral disk (IVD) degeneration.Kepler et al. reviewed IVD degeneration. They report that degeneration leads to changes in the expression of matrix proteins, cytokines, and proteinases. They suggest treatment with gene therapy, such as Growth and Differentiation Factor-5 (GDF-5), may help to promote the healing of degenerated intervertebral disks.Illustration A shows a cadaveric image of normal disk anatomy (left) and IVD degeneration (right)Incorrect Answers:

Question 2185

Topic: 6. Spine

A 44-year-old man was involved in a low speed rear-end motor vehicle accident 4 weeks ago. He predominantly reports pain in the back of the neck, with occasional radiation into the trapezius region bilaterally. He denies any extremity pain. The pain has not changed in intensity, but is worse with neck range of motion. Cervical spine radiographs were negative for acute osseous trauma or instability. What is the next most appropriate step in management? Review Topic

. Continued observation
. Cervical epidural injections
. Nonsteroidal anti-inflammatory drugs (NSAIDs), activity modification, and physical therapy
. Cervical facet blocks
. Cervical MRI

Correct Answer & Explanation

. Continued observation

Explanation

The patient was involved in a low speed rear-end collision and sustained a whiplash-type injury, with management most often being nonsurgical. After 4 weeks of persistent pain, continued observation is not reasonable. Studies have shown that treatment including NSAIDs, activity modification and a brief duration of physical therapy allows for improved outcomes after whiplash-type injuries when compared with observation alone. An MRI scan of the cervical spine is not indicated at this time and represents an unnecessary expense. Cervical epidural and facet injections are not indicated in the treatment of patients with whiplash injuries.

Question 2186

Topic: 6. Spine

A 15-year-old boy reports a 2-day history of progressive left buttock pain and severe limping. He denies any history of trauma or radiation of the pain. He has an oral temperature of 100.4 degrees F (38 degrees C). Examination reveals that the lumbar spine and left hip have unguarded motion. The abdomen is nontender. There is moderate tenderness of the left sacroiliac region with no palpable swelling. Pain is elicited when the left lower extremity is placed in the figure-4 position (FABER test). Laboratory studies show a peripheral WBC count of 11,500/mmP3P (normal to 10,500/mmP3P) and an erythrocyte sedimentation rate of 38 mm/h (normal up to 20 mm/h). Radiographs of the pelvis, hips, and lumbar spine are normal. A nucleotide bone scan (posterior view) is shown in Figure 44. Initial management should consist of Review Topic

. oral nonsteroidal anti-inflammatory drugs.
. intravenous antistaphylococcal antibiotics.
. incision and debridement of the retroperitoneal abscess.
. incision and debridement of the left sacroiliac joint.
. arthrotomy and irrigation of the left hip joint.

Correct Answer & Explanation

. oral nonsteroidal anti-inflammatory drugs.

Explanation

The symptoms, physical findings, and laboratory studies are most consistent with a diagnosis of infectious sacroiliitis, usually caused by Staphylococcus aureus. Initial radiographs will be normal, and the diagnosis of sacroiliitis is often delayed. A technetium Tc 99m bone scan will localize the problem in 90% of patients but may occasionally give a false-negative result in early cases. If suspicion is high, a gallium scan or MRI scan may help confirm the diagnosis of sacroiliitis. Needle aspiration of the sacroiliac joint is difficult; therefore, antibiotic selection is usually empiric or based on blood cultures. Sacroiliitis that is the result of connective tissue inflammatory disease is usually bilateral and without fever or leukocytosis. The lack of hip irritability, spinal rigidity, and abdominal tenderness helps to rule out other causes of limping with fever, such as psoas abscess, diskitis, and septic hip.

Question 2187

Topic: 6. Spine
The thickest bone in the occiput is located
. in no predictable pattern.
. at the level of the foramen magnum.
. at the level of the external occipital protuberance.
. 4 cm below the external occipital protuberance.
. 4 cm lateral to the external occipital protuberance.

Correct Answer & Explanation

. at the level of the external occipital protuberance.

Explanation

Anatomic studies have shown that the thickest bone of the occiput is at the level of the external occipital protuberance. In general, the bone thins as it extends distally from the external occipital protuberance and it also moves laterally from the midline.

Question 2188

Topic: 6. Spine
A 30-year-old woman sustained a nondisplaced unilateral facet fracture of C5 in a motor vehicle accident. She is neurologically intact and has no other injuries. Management should consist of
. skeletal tong traction for 6 weeks.
. halo application.
. immobilization in a rigid collar for 6 weeks.
. open reduction posteriorly with interspinous wiring and bone grafting.
. open reduction anteriorly with diskectomy, interbody grafting, and plating.

Correct Answer & Explanation

. immobilization in a rigid collar for 6 weeks.

Explanation

DISCUSSION: The patient has a stable bony fracture that will heal with immobilization in a rigid collar. Flexion-extension radiographs may be obtained at 6 weeks to verify that there is no instability; mobilization may then be begun. REFERENCE: Clarke CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott-Raven, 1998, pp 457-464.

Question 2189

Topic: 6. Spine
A sentinel event is defined as an unexpected occurrence involving death or serious physical or psychological injury, or the risk thereof. What is the most common sentinel event related to spine surgery?
. Surgery on the wrong patient
. Surgery on the wrong side
. Incorrect procedure performed
. Intraoperative death
. Surgery on the wrong level

Correct Answer & Explanation

. Surgery on the wrong level

Explanation

DISCUSSION: Patient safety and prevention of medical errors is a major focus of recent national advocacy groups. Analysis has shown that the most common sentinel event in spine surgery is surgery on the wrong level. Therefore, it is recommended that every patient have the surgical site signed, the level of surgery marked intraoperatively, and a radiograph taken. Surgery on the wrong level is most likely to occur in single-level decompressive procedures. REFERENCES: Wong DA, Watters WC III: To err is human: Quality and safety issues in spine care. Spine 2007;32:S2-S8. Wong DA: Spinal surgery and patient safety: A systems approach. J Am Acad Orthop Surg 2006;14:226-232.

Question 2190

Topic: 6. Spine
Which of the following changes occur in the spinal cord and the spinal canal when the cervical spine moves from neutral to full flexion?
. The spinal cord relaxes and the spinal canal shortens.
. The spinal cord undergoes elastic deformation and the spinal canal lengthens.
. The spinal cord remains unchanged and the spinal canal lengthens.
. The spinal cord remains unchanged and the spinal canal shortens.
. Neither structure shows any predictable pattern of changes.

Correct Answer & Explanation

. The spinal cord undergoes elastic deformation and the spinal canal lengthens.

Explanation

The spinal cord and spinal canal undergo dynamic changes during neck flexion and extension. In neck flexion, the spinal cord initially unfolds and then undergoes elastic deformation with full flexion; the spinal canal lengthens. This may explain the presence of Lhermitte’s sign as the cord is pulled anteriorly over an anterior osteophyte or disk, generating a compressive force on the spinal cord. During neck extension, the spinal cord relaxes (folding like an accordion) and the spinal canal shortens.

Question 2191

Topic: 6. Spine

A 63-year-old man has a feeling of generalized clumsiness in his arms and hands, difficulty buttoning his shirt, and gradually worsening gait instability. During examination, his neck is gently passively flexed to end range while he is seated. The patient describes an electric shock-like sensation that radiates down the spine and into the extremities. This describes which of the following? Review Topic

. A positive Lhermitte sign
. A positive Spurling sign
. A positive Jackson sign
. A positive Lasegue sign
. A positive Hoffmann sign

Correct Answer & Explanation

. A positive Lhermitte sign

Explanation

What is now referred to as Lhermitte sign was first described by Marie and Chatelin in 1917 to describe "transient 'pins and needles' sensations traveling the spine and limbs on flexion of the head" in some patients with head injuries. A positive test is indicated by the presence of electric-like sensation down the spine or extremities. It is associated with cervical spinal cord pathology from a wide variety of etiologies, including multiple sclerosis. Recent studies suggest that it has a low sensitivity and high specificity. Spurling's sign is elicited by axial compression of the tilted head. Jackson's sign is elicited by hyperextension of the cervical spine. Lasegue sign refers to the straight leg raise with dorsiflexion of the ankle for lumbar radiculopathy. Hoffmann sign is a pathologic reflex of the upper extremity, that is felt to be an indicator of cervical myelopathy.

Question 2192

Topic: 6. Spine

Figures 42a through 42c show the MRI scans of a 56-year-old woman with progressively worsening low back and bilateral lower extremity pain. Based on these images, what muscle or muscle group would be expected to be weak on physical examination? Review Topic

. Quadriceps
. Hamstrings
. Hip adductors
. Extensor hallucis longus
. Gastrocnemius

Correct Answer & Explanation

. Quadriceps

Explanation

Whereas subjective complaints of leg pain are common among patients seeking surgical treatment for spondylolisthesis, documented neurologic deficit or radiculopathy is seen less frequently. Subjective decreases to light touch over the dorsum of the foot and mild weakness of the extensor hallucis longus are the most common neurologic abnormalities, correlating with L5 nerve root irritation as seenwith L5-S1 spondylolisthesis. Many patients with spondylolisthesis report hamstring tightness; however, these structures are not usually weak. Quadriceps and tibialis anterior weakness is seen with L4 nerve root irritation. The gastrocnemius is generally weak in S1 nerve root syndromes.

Question 2193

Topic: 6. Spine
Which of the following correctly describes a physical or molecular change in the degenerative pathway of intervertebral disk disease?
. Decreased type II collagen in the nucleus pulposus
. Increased water content in the nucleus pulposus
. Increased type IX collagen in the nucleus pulposus
. Decrease in the keratin sulfate-to-chondroitin sulfate ratio in the nucleus pulposus
. Decrease in type I collagen in the annular fibrosus

Correct Answer & Explanation

. Decreased type II collagen in the nucleus pulposus

Explanation

A reduction in type II collagen synthesis is a pathological process in the degenerative pathway of intervertebral disk disease (IVD). There are many physical and molecular changes in the degenerative pathway of intervertebral disk disease. These include: DECREASE: Synthesis of collagen types II and IX, nutritional transport, water content, absolute number of viable cells, proteoglycans, and pH. INCREASE: Synthesis of collagen types I and X, keratin sulfate-to-chondroitin sulfate ratio, lactate, and degradative enzyme activity.

Question 2194

Topic: 6. Spine
A 62-year-old man with a long history of ankylosing spondylitis has neck pain after lightly bumping his head on the wall. Examination reveals neck pain with any attempted motion; the neurologic examination is normal. Plain radiographs show extensive ankylosis of the cervical spine and kyphosis but no fracture. What is the next most appropriate step in management?
. Application of a rigid collar and follow-up radiographs in 1 week
. Gardner-Wells tongs and in-line traction
. Hospital admission and frequent neurologic checks
. Immobilization of the neck, followed by CT with reconstruction
. Flexion-extension radiographs to evaluate for any occult instability

Correct Answer & Explanation

. Immobilization of the neck, followed by CT with reconstruction

Explanation

A high level of suspicion must be given for a fracture in any patient with ankylosing spondylitis who reports neck pain, even with minimal or no trauma. The neck should be immobilized in its normal position, which is often kyphotic, and plain radiographs should be obtained. If no obvious fracture is seen, CT with reconstruction should be obtained. The placement of in-line traction can have catastrophic effects because it may malalign the spine.

Question 2195

Topic: 6. Spine
Radiating pain associated with a posterolateral thoracic disk herniation typically follows what pattern?
. Extending down the spine into the lumbosacral region
. Down the inner aspect of either upper extremity
. Cephalad up to the cervicothoracic junction
. Around or through the chest to the anterior wall
. Down the contralateral lower extremity

Correct Answer & Explanation

. Around or through the chest to the anterior wall

Explanation

DISCUSSION: Although symptomatic thoracic disk herniations can affect more caudal structures, even to the point of paralysis, the pattern of radiating pain has been described as either following the dermatomal band around the chest or feeling to the patient as if the pain passes straight anteriorly to the chest wall. REFERENCE: Skubic JW, Kostuik JP: Thoracic pain syndromes and thoracic disc herniation, in Frymoyer JW (ed): The Adult Spine: Principles and Practice. New York, NY, Raven Press, 1991, pp 1443-1464.

Question 2196

Topic: 6. Spine
In a patient who has undergone fusion with instrumentation from T4 to the sacrum for adult scoliosis, at which site is a pseudarthrosis most likely to be discovered?
. T4-T5
. T7-T8
. L2-L3
. L4-L5
. L5-S1

Correct Answer & Explanation

. L5-S1

Explanation

DISCUSSION: Although pseudarthrosis can be found anywhere within the spine that has been fused using long multisegmental fixation to the sacrum, it most commonly occurs at the lumbosacral junction. The thoracolumbar junction is another common site of potential pseudarthrosis. In this location, the anatomy changes from lumbar transverse processes to thoracic through the transition zone, and overlying instrumentation often makes it difficult to obtain enough sound bone on decorticated bone to achieve a successful fusion. REFERENCES: Saer EH III, Winter RB, Lonstein JE: Long scoliosis fusion to the sacrum in adults with nonparalytic scoliosis: An improved method. Spine 1990;15;650-653. Kostuik JP, Hall BB: Spinal fusions to the sacrum in adults with scoliosis. Spine 1983;8:489-500. Balderston RA, Winter RB, Moe JH, et al: Fusion to the sacrum for nonparalytic scoliosis in the adult. Spine 1986;11:824-829.

Question 2197

Topic: 6. Spine
Figures 9a through 9c are the preoperative radiographs and a T2-weighted MR image of a patient treated with surgery for spondylolisthesis and neuroforaminal stenosis. Figure 9d is the postsurgical radiograph. Interbody fusion offers which advantage over posterolateral fusion (PLF)?
. Decreased blood loss
. Less neural retraction
. Improved neuroforaminal height
. Lower fusion rates

Correct Answer & Explanation

. Improved neuroforaminal height

Explanation

DISCUSSION: Interbody fusion, when compared to PLF, is a predictor of more substantial blood loss. Multilevel posterior lumbar interbody fusion (PLIF) is an independent predictor of blood loss for posterior spine fusion. Some retrospective studies suggest that fusion rates are higher for transforaminal lumbar interbody fusion (TLIF) than PLF, but this finding has not been borne out in prospective studies. The main advantage of TLIF in the context of this question is restoration of neuroforaminal height, and many surgeons will consider TLIF or PLIF for that reason. The parasagittal MR image seen in Figure 9c shows neuroforaminal narrowing. The pre- and postsurgical radiographs show a difference in neuroforaminal height.

Question 2198

Topic: 6. Spine
A 3-year-old girl developed torticollis eight months ago after a severe respiratory tract infection. An initial trial of halter traction was attempted without success. A trial of halo traction was then performed for 3 weeks and then a dynamic computed tomographic (CT) scan was obtained and shown in Figure A. Panel (a) shows an axial image with maximal rotation to the left. Panel (b) shows an axial image with maximal rotation to the right. What is the most appropriate next step in management?
. No further treatment
. Closed reduction under conscious sedation
. Closed reduction under general anesthesia in the operating room with neurologic monitoring
. Occipitocervical fusion
. Posterior atlantoaxial fusion

Correct Answer & Explanation

. Posterior atlantoaxial fusion

Explanation

The clinical presentation is consistent with chronic torticollis caused by atlantoaxial rotatory displacement (AARD). Because both halter traction and halo traction were attempted and failed, the next most appropriate step in management is posterior atlantoaxial fusion. Common causes of AARD include infection, trauma, and recent neck surgery. Diagnosis is best confirmed with dynamic CT. If nonoperative modalities fail, the condition has been present for > 3 months, or the patient has neurologic deficits, then posterior C1-C2 fusion is indicated.

Question 2199

Topic: 6. Spine

-What gene is implicated in spinal muscular atrophy?

. Survival motor neuron I (SMN-I)
. Peripheral myelin protein 22 (PMP22)
. Dystrophin
. Androgen receptorDISCUSSION-Deletions in the SMN-I gene are found in 95% to 98% of patients with spinal muscular atrophy. Genetic testing is typically part of the diagnostic workup for spinal muscular atrophy. A positive test result is diagnostic, and, in most cases, eliminates the need for muscle biopsy. The other choices are not associated with spinal muscular atrophy. Defects in PMP22 are the cause of 70% to 80% of cases of Charcot-Marie-Tooth disease. Mutations in the dystrophin gene cause Duchenne muscular dystrophy, and mutations in the androgen receptor cause spinobulbar muscular atrophy (Kennedy’s disease).

Correct Answer & Explanation

. Survival motor neuron I (SMN-I)

Explanation

Question 2200

Topic: 6. Spine

A patient has a C6 spinal cord injury. Following stabilization of the spine, the patient should be advised that their expected maximum level of function

. An electric wheelchair with puffer control
. An electric wheelchair with hand controls
. A manual wheelchair and sliding board transfers
. A manual wheelchair and independent transfers
. Crutches with long leg braces for short distance ambulation

Correct Answer & Explanation

. A manual wheelchair and sliding board transfers

Explanation

A patient with an injury at the level of: C4 injury needs puffer control; C5 can use hand controls; C6 can use a manual wheelchair and sliding board transfers; C7 allows independent transfers; and no cervical injury routinely allows ambulation with crutches and leg braces.

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