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6. Spine MCQs

Practice Set 319 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 6361

Topic: 6. Spine

A patient falls from a height of 20 feet and sustains a complex spinopelvic dissociation, specifically a U-type sacral fracture (bilateral vertical sacral fractures connected by a transverse fracture component). Due to the anatomic location of the transverse limb of this fracture, which neurological deficit is most frequently encountered?

. Femoral nerve palsy with absent patellar reflex
. Obturator nerve palsy with weak hip adduction
. Cauda equina syndrome presenting as bowel, bladder, and sexual dysfunction
. Isolated foot drop due to common peroneal nerve injury
. Pudendal nerve entrapment at the ischial spine

Correct Answer & Explanation

. Femoral nerve palsy with absent patellar reflex

Explanation

U-type sacral fractures result in spinopelvic dissociation, where the upper sacrum (and attached spine) dissociates from the lower sacrum and pelvis. The transverse component of the fracture most commonly crosses through the upper sacral foramina (S1, S2, or S3). This displacement severely compromises the sacral nerve roots running in the central canal, heavily associating this injury with Cauda Equina Syndrome (manifesting as bowel, bladder dysfunction, and saddle anesthesia).

Question 6362

Topic: 6. Spine
A 53-year-old man reports acute, severe left shoulder pain after undergoing abdominal surgery 10 days ago. Initial management, consisting of anti-inflammatory drugs, physical therapy, and a subacromial injection of corticosteroid, fails to provide relief. Reexamination of the shoulder 2 months after the onset of symptoms reveals atrophy of the infraspinous and supraspinous fossa and profound weakness of active abduction and external rotation. His neck is supple with a full range of motion. Plain radiographs and an MRI scan of the shoulder are normal. What diagnostic study should be performed next in the evaluation of this patient?
. Shoulder arthrography
. MRI of the cervical spine
. CT of the head
. Technetium Tc 99m bone scan
. Electromyography and nerve conduction velocity studies

Correct Answer & Explanation

. Electromyography and nerve conduction velocity studies

Explanation

Suprascapular nerve palsy is a fairly uncommon yet well-known cause of shoulder pain and weakness. In this patient, the injury is most likely caused by traction or compression of the nerve in the suprascapular notch as the result of positioning during abdominal surgery; therefore, the studies of choice are electromyography and nerve conduction velocity studies.

Question 6363

Topic: 6. Spine

When an anterior approach to the cervical spine is being performed, many

2. surgeons prefer the left-sided approach to the right-sided approach because on

3. the left side the recurrent laryngeal nerve is

4. 1- larger.

5. 2- more consistent in location.

6. 3- entirely within the carotid sheath.

7. 4- well protected by the strap muscles of the neck.

8. 5- located between the longus colli and the esophagus.

. surgeons prefer the left-sided approach to the right-sided approach because on
. the left side the recurrent laryngeal nerve is
. larger.
. more consistent in location.
. entirely within the carotid sheath.

Correct Answer & Explanation

. surgeons prefer the left-sided approach to the right-sided approach because on

Explanation

1.1.next question1. Reference(s)2. Hoppenfeld S, deBoer P (eds): Surgical Exposures in Orthopaedics: The Anatomic Approach, ed 1. Philadelphia, PA, JB Lippincott, 1984, pp 265-269.#

Question 6364

Topic: 6. Spine
During an anterior approach to correct thoracolumbar scoliosis, there is a sudden decrease in somatosensory-evoked potential (SSEP) and motor-evoked potential (MEP) signals. Correction maneuvers have not been attempted when signals go down. All neuromonitoring and anesthesia concerns have been addressed, and the measured abnormalities persist. What is the likely reason behind the neuromonitoring abnormalities?
. Occlusion of the artery of Adamkiewicz
. Neurapraxia
. Mechanical injury to the cord via instrumentation
. False positive, proceed as planned

Correct Answer & Explanation

. Occlusion of the artery of Adamkiewicz

Explanation

The artery of Adamkiewicz originates in more than 90% of patients between T8 and L1. It has been postulated that the artery of Adamkiewicz is the primary blood supply to the thoracic spinal cord. Standard anterior retroperitoneal- and thoracotomy-based approaches typically necessitate sacrifice of segmental vessels that can disrupt blood supply to the anterior thoracic cord.

Question 6365

Topic: 6. Spine

A 56-year-old man has a chief complaint of leg weakness and inability to walk. Examination reveals 5out of 5 motor strength in all lower extremity muscle groups tested and normal sensation to light touch in

both lower extremities. The patient is slow in getting up from a seated position and has an unsteady widebased gait. An MRI scan of the lumbar spine is shown in Figure

. What is the next most appropriate course of action?
. Electromyography and nerve conduction velocity studies of bilateral lower extremities
. Multilevel lumbar laminectomy
. MRI of the thoracic and cervical spine
. MRI of the brain

Correct Answer & Explanation

. What is the next most appropriate course of action?

Explanation

The patient is having gait problems suspicious for spinal cord compression. MRI of the thoracic and cervical spine should be performed to evaluate for spinal cord compression. Reports of legweakness in the absence of discrete motor weakness on manual testing, and the appearance of an unsteady wide-based gait are more consistent with myelopathy as a cause of the gait difficulty rather than lumbar stenosis. Although the MRI scan of the lumbar spine shows multilevel spinal stenosis that is mild to moderate, it does not clearly explain the patient’s signs and symptoms. Electromyography and nerve conduction velocity studies of the lower extremities are unlikely to add significantly to the diagnosis.Epidural steroid injections are not indicated. Lumbar decompression is unlikely to help the patient because the source of the patient’s problem does not originate in the lumbar spine. MRI of the brain could be considered as a secondary imaging study if the cervical and thoracic MRI scans fail to identify an obvious cause for gait instability.

Question 6366

Topic: 6. Spine
A 16-year-old boy with type I Ehlers-Danlos syndrome has a spinal curvature that has progressed 18° in the past year. The curve is a double major type with a Cobb angle of 60° in each curve. There is no associated kyphosis. The following treatment is recommended:
. Observation
. Bracing
. Anterior fusion and instrumentation
. Posterior fusion and instrumentation
. Anterior and posterior fusion with instrumentation

Correct Answer & Explanation

. Posterior fusion and instrumentation

Explanation

Posterior fusion and instrumentation is the best-documented treatment. Although this form of treatment is followed by an increased incidence of wound healing problems, the problems can be treated. Observation is not recommended because the curve is highly likely to increase and cause a decrease in pulmonary function. Bracing has no role in large curves, and it is not known if bracing is successful in Ehlers-Danlos syndrome. Anterior fusion with instrumentation would be difficult with a double curve. Anterior fusion carries an increased risk due to vascular fragility. It is not necessary because there is no increased risk of crankshaft or pseudarthrosis. There is no particular reason for adding an anterior procedure in this situation in view of the vascular risk.

Question 6367

Topic: 6. Spine

In the evaluation of a 60-year-old male presenting with bilateral hand clumsiness and gait instability, the examiner elicits a positive Hoffman's sign. What pathophysiologic entity does a positive Hoffman's sign suggest?

. Lower motor neuron lesion at the C5-C6 level
. Upper motor neuron lesion involving the cervical spinal cord
. Peripheral entrapment neuropathy of the median nerve
. Brachial plexopathy involving the lower trunk
. Cervical radiculopathy of the C8 nerve root

Correct Answer & Explanation

. Lower motor neuron lesion at the C5-C6 level

Explanation

Hoffman's sign is elicited by flipping the volar aspect of the distal phalanx of the middle finger; a positive response is a reflex flexion of the thumb and/or index finger. It is a sign of hyperreflexia and indicates an upper motor neuron (UMN) lesion, classically pointing to compression or dysfunction of the spinal cord in the cervical region (cervical myelopathy) above the C7 level.

Question 6368

Topic: 6. Spine

A 45-year-old male presents with acute severe lower back pain, bilateral lower extremity weakness, saddle anesthesia, and urinary retention. MRI confirms a massive central L4-L5 disc herniation compressing the cauda equina. Current evidence suggests that surgical decompression is most strongly associated with improved recovery of bladder and motor function if performed within what timeframe from the onset of autonomic symptoms?

. 12 hours
. 24 hours
. 48 hours
. 72 hours
. 1 week

Correct Answer & Explanation

. 12 hours

Explanation

Cauda equina syndrome is an orthopedic and neurosurgical emergency. While decompression should be performed as safely and quickly as possible, extensive meta-analyses (such as the landmark review by Ahn et al.) have demonstrated a significant difference in outcomes—specifically regarding the reversal of motor and autonomic (bladder/bowel) deficits—when surgical decompression is performed within 48 hours of the onset of symptoms, compared to after 48 hours.

Question 6369

Topic: Cervical Spine

A 80-year-old male with a history of severe COPD and ischemic heart disease presents after a mechanical fall with neck pain. A CT scan of the cervical spine demonstrates a Type II odontoid fracture with 2 mm of displacement. What is the most appropriate initial management strategy for this patient?

. Halo vest immobilization
. Anterior odontoid screw fixation
. Posterior C1-C2 transarticular screw fixation
. Rigid cervical collar immobilization
. Observation with soft collar

Correct Answer & Explanation

. Halo vest immobilization

Explanation

In elderly patients with Type II odontoid fractures, especially those with significant comorbidities, a rigid cervical collar is generally preferred. While nonunion rates are higher compared to surgical fixation, halo vest immobilization carries an unacceptably high mortality and morbidity rate in the elderly population.

Question 6370

Topic: 6. Spine

A 40-year-old male is involved in a high-speed motor vehicle collision. CT of the cervical spine reveals bilateral pars interarticularis fractures of C2 with 4 mm of anterior translation of C2 on C3 and severe C2-C3 intervertebral disc disruption (Effendi Type II Hangman's fracture). What is the classic mechanism of injury for this fracture pattern?

. Hyperextension and axial loading
. Hyperflexion and rotation
. Axial distraction and hyperextension
. Lateral bending and compression
. Axial loading and hyperflexion

Correct Answer & Explanation

. Hyperextension and axial loading

Explanation

A classic Hangman's fracture (traumatic spondylolisthesis of the axis) occurs via a mechanism of hyperextension and axial distraction. This mechanism was historically seen in judicial hangings and is now commonly associated with sudden deceleration in motor vehicle accidents.

Question 6371

Topic: 6. Spine

A 65-year-old male presents with deteriorating handwriting, clumsiness in his hands, and a wide-based gait. On examination, rapidly flicking the distal phalanx of the middle finger downward produces involuntary flexion of the thumb and index finger. What does this physical sign indicate?

. Upper motor neuron lesion (Hoffmann sign)
. Lower motor neuron lesion
. Peripheral neuropathy
. Normal aging reflex
. Isolated cervical radiculopathy

Correct Answer & Explanation

. Upper motor neuron lesion (Hoffmann sign)

Explanation

The Hoffmann sign evaluates for upper motor neuron hyperreflexia and is strongly suggestive of cervical spondylotic myelopathy. It is considered the upper extremity equivalent of the Babinski reflex.

Question 6372

Topic: 6. Spine

A 68-year-old male complains of bilateral posterior leg pain and heaviness that worsens with walking and standing. He notes significant relief when sitting or leaning forward on a shopping cart. Peripheral pulses are 2+ bilaterally. What is the primary pathophysiological mechanism underlying his symptoms?

. Arterial occlusion causing muscular ischemia
. Venous insufficiency leading to dependent pooling
. Central spinal canal narrowing compressing the cauda equina
. Herniated nucleus pulposus compressing a single exiting nerve root
. Spondylolysis causing pars interarticularis microfractures

Correct Answer & Explanation

. Arterial occlusion causing muscular ischemia

Explanation

This presentation is classic for neurogenic claudication due to central lumbar spinal stenosis. Leaning forward (lumbar flexion) increases the cross-sectional area of the central canal, transiently relieving pressure on the neural elements.

Question 6373

Topic: 6. Spine

A 65-year-old male presents with deteriorating handwriting, frequent dropping of objects, and a broad-based, unsteady gait. Physical examination reveals bilateral hyperreflexia, a positive Hoffmann sign, and inverted radial reflex. What is the most likely diagnosis?

. Lumbar spinal stenosis
. Cervical spondylotic myelopathy
. Amyotrophic lateral sclerosis
. Guillain-Barre syndrome
. Severe bilateral carpal tunnel syndrome

Correct Answer & Explanation

. Lumbar spinal stenosis

Explanation

Cervical spondylotic myelopathy classically presents with upper extremity clumsiness, gait instability, and upper motor neuron signs. It is the most common cause of acquired spastic paresis in adults over the age of 55.

Question 6374

Topic: 6. Spine

A patient with severe rheumatoid arthritis presents with progressive cervical myelopathy. Flexion-extension radiographs show 9 mm of atlantoaxial subluxation (AAS). Which radiographic parameter is the most critical predictor of postoperative neurological recovery?

. Anterior atlantodens interval (ADI)
. Posterior atlantodens interval (PADI)
. Ranawat criterion
. Clark station
. McGregor's line

Correct Answer & Explanation

. Anterior atlantodens interval (ADI)

Explanation

The Posterior Atlantodens Interval (PADI), which represents the space available for the spinal cord, is the most reliable predictor of neurologic recovery in RA patients with AAS. A PADI of less than 14 mm is an indication for surgical stabilization.

Question 6375

Topic: Thoracolumbar Spine & Deformity

A 30-year-old male is diagnosed with an L1 burst fracture after a fall. He is neurologically intact, and MRI confirms an intact posterior ligamentous complex. His TLICS score is 2. What is the most appropriate management?

. Anterior corpectomy and fusion
. Posterior pedicle screw fixation one level above and below
. Thoracolumbosacral orthosis (TLSO) brace
. Laminectomy and facet fusion
. Percutaneous vertebroplasty

Correct Answer & Explanation

. Anterior corpectomy and fusion

Explanation

A Thoracolumbar Injury Classification and Severity (TLICS) score of 3 or less indicates non-operative management. For an isolated burst fracture with intact neurology and posterior ligaments, a TLSO brace is the standard of care.

Question 6376

Topic: 6. Spine

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is utilized in anterior cervical discectomy and fusion (ACDF) to enhance arthrodesis rates. Which of the following is the most significant recognized complication associated with its use in the anterior cervical spine?

. Pseudarthrosis
. Malignant transformation
. Prevertebral soft tissue swelling
. Vertebral artery injury
. Recurrent laryngeal nerve transection

Correct Answer & Explanation

. Pseudarthrosis

Explanation

The use of rhBMP-2 in the anterior cervical spine is highly associated with significant prevertebral soft tissue swelling. This can lead to severe dysphagia, airway compromise, and occasionally requires emergency intubation.

Question 6377

Topic: 6. Spine

A 45-year-old man presents to the emergency department with severe lower back pain, new-onset bilateral leg weakness, and urinary retention with overflow incontinence. MRI confirms a massive L4-L5 central disc herniation. To maximize the chance of complete neurological recovery, surgical decompression should ideally be performed within what timeframe from symptom onset?

. 6 hours
. 24 hours
. 48 hours
. 72 hours
. 1 week

Correct Answer & Explanation

. 6 hours

Explanation

Cauda equina syndrome is an orthopedic and neurosurgical emergency. Current literature strongly supports that surgical decompression within 48 hours of symptom onset significantly improves the likelihood of a complete return of bowel and bladder function.

Question 6378

Topic: 6. Spine

A 45-year-old male is diagnosed with acute Cauda Equina Syndrome secondary to a massive L4-L5 disc herniation. Surgical decompression is most optimal to maximize the return of bladder and bowel function if performed within which time frame?

. 6 hours
. 24 to 48 hours
. 72 hours
. 5 days
. 1 week

Correct Answer & Explanation

. 6 hours

Explanation

Current literature suggests that surgical decompression within 24 to 48 hours of symptom onset significantly improves outcomes for bowel, bladder, and sexual function. Outcomes rapidly deteriorate if delayed beyond 48 hours.

Question 6379

Topic: 6. Spine

A 45-year-old man presents with severe right leg pain, weakness in ankle dorsiflexion, and numbness extending to the dorsum of his foot. MRI reveals a large posterolateral disc herniation at the L4-L5 level. Which nerve root is most likely affected?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L3

Explanation

In the lumbar spine, a posterolateral disc herniation typically affects the traversing nerve root, which is the root of the lower segment. Thus, an L4-L5 herniation compresses the traversing L5 nerve root.

Question 6380

Topic: 6. Spine

A 55-year-old female presents with neck pain radiating to her right thumb. Examination reveals weakness in wrist extension and a diminished brachioradialis reflex. Which cervical disc level is most likely herniated?

. C3-C4
. C4-C5
. C5-C6
. C6-C7
. C7-T1

Correct Answer & Explanation

. C3-C4

Explanation

A C5-C6 disc herniation compresses the C6 nerve root. C6 radiculopathy typically presents with weakness in wrist extension and elbow flexion, numbness in the thumb, and a diminished brachioradialis reflex.

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