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6. Spine MCQs

Practice Set 268 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 5341

Topic: Thoracolumbar Spine & Deformity

In a patient with symptomatic L5-S1 isthmic spondylolisthesis, which nerve root is most commonly compressed, and where does the compression typically occur?

. L5 nerve root within the lateral recess
. L5 nerve root in the neural foramen
. S1 nerve root within the lateral recess
. S1 nerve root in the neural foramen
. S2 nerve root centrally

Correct Answer & Explanation

. L5 nerve root in the neural foramen

Explanation

In isthmic spondylolisthesis, the exiting L5 nerve root is most commonly compressed. This compression typically occurs within the neural foramen due to the hypertrophic fibrocartilaginous mass at the pars interarticularis defect.

Question 5342

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male sustains an L1 burst fracture. He is neurologically intact. MRI demonstrates an intact posterior ligamentous complex. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate treatment?

. Posterior instrumented fusion from T11 to L3
. Anterior corpectomy and fusion
. Thoracolumbosacral orthosis (TLSO)
. Short-segment posterior fusion
. Vertebroplasty

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO)

Explanation

This patient has a TLICS score of 2 (burst fracture morphology = 2, intact PLC = 0, neurologically intact = 0). A score of 3 or less is an indication for non-operative management, making a TLSO brace the most appropriate treatment.

Question 5343

Topic: 6. Spine

A 55-year-old male presents with difficulty buttoning his shirts and a clumsy gait. Examination reveals hyperreflexia in the lower extremities and a positive Hoffmann's sign. Radiographs show severe cervical spondylosis. The earliest clinical presentation of this condition is most commonly associated with dysfunction of which spinal tract?

. Spinothalamic tract
. Corticospinal tract
. Dorsal columns
. Spinocerebellar tract
. Vestibulospinal tract

Correct Answer & Explanation

. Corticospinal tract

Explanation

The patient has cervical spondylotic myelopathy. The earliest findings are typically fine motor dysfunction in the hands and gait unsteadiness, primarily due to involvement of the lateral corticospinal tracts.

Question 5344

Topic: 6. Spine
A 70-year-old male with pre-existing cervical stenosis sustains a hyperextension injury to his neck. He presents with profound weakness in his upper extremities and relatively preserved motor function in his lower extremities. What is the most likely diagnosis?
. Anterior cord syndrome
. Brown-Sรฉquard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome is characterized by disproportionately greater motor impairment in the upper extremities compared to the lower extremities. It typically occurs after a hyperextension injury in a patient with pre-existing cervical canal stenosis.

Question 5345

Topic: 6. Spine

A 45-year-old intravenous drug user presents with severe lower back pain, fever, and progressive bilateral leg weakness over the past 48 hours. He has urinary retention and decreased perianal sensation. MRI reveals an L3-L4 epidural abscess. What is the most appropriate definitive management?

. Intravenous antibiotics alone for 6 weeks
. CT-guided aspiration of the abscess
. Emergent surgical decompression and debridement
. Lumbar drain placement
. High-dose intravenous corticosteroids

Correct Answer & Explanation

. Emergent surgical decompression and debridement

Explanation

The patient has a spinal epidural abscess presenting with acute cauda equina syndrome. This is an absolute surgical emergency requiring immediate decompression and debridement, followed by targeted antibiotic therapy.

Question 5346

Topic: Cervical Spine

A 25-year-old male sustains a Type IIa Hangman's fracture following a motor vehicle collision. Radiographs show severe anterior angulation of C2 on C3 without significant translation. What is the most appropriate non-operative management?

. Cervical traction followed by a rigid collar
. Halo vest application with the neck in slight compression and extension
. Immediate rigid collar placement in the neutral position
. Halo vest application with the neck in flexion
. High-weight skeletal traction for 6 weeks

Correct Answer & Explanation

. Halo vest application with the neck in slight compression and extension

Explanation

Type IIa Hangman's fractures involve severe angulation via an atypical flexion-distraction mechanism. Traction is strictly contraindicated as it worsens the deformity; they should be treated with gentle compression and extension in a halo vest.

Question 5347

Topic: 6. Spine

A patient presents with acute, severe right-sided radicular leg pain. MRI demonstrates a far-lateral (extraforaminal) disc herniation at the L4-L5 level on the right. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L4

Explanation

In the lumbar spine, a far-lateral (extraforaminal) disc herniation compresses the exiting nerve root at that corresponding level. Therefore, an L4-L5 far-lateral disc compresses the L4 nerve root.

Question 5348

Topic: Thoracolumbar Spine & Deformity

In the assessment of spinopelvic parameters, which of the following is considered a fixed morphological parameter of the pelvis that is unaffected by the patient's posture?

. Pelvic tilt (PT)
. Sacral slope (SS)
. Pelvic incidence (PI)
. Lumbar lordosis (LL)
. Sagittal vertical axis (SVA)

Correct Answer & Explanation

. Pelvic incidence (PI)

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter that does not change with positioning after skeletal maturity. It mathematically equals the sum of pelvic tilt and sacral slope (PI = PT + SS).

Question 5349

Topic: Cervical Spine

What is the primary advantage of cervical disc arthroplasty over anterior cervical discectomy and fusion (ACDF) based on long-term randomized trials?

. Reduced operative time and surgical bleeding
. Lower rate of adjacent segment degeneration requiring reoperation
. Higher fusion rate at the index segment
. Less risk of recurrent laryngeal nerve palsy
. Elimination of postoperative dysphagia

Correct Answer & Explanation

. Lower rate of adjacent segment degeneration requiring reoperation

Explanation

Long-term randomized controlled trials have demonstrated that cervical disc arthroplasty results in a lower rate of adjacent segment degeneration requiring reoperation compared to ACDF. Arthroplasty preserves motion at the index level, theoretically reducing biomechanical stress on adjacent segments.

Question 5350

Topic: 6. Spine

A 65-year-old man presents with bilateral upper extremity weakness (distal greater than proximal) and mild lower extremity weakness following a hyperextension injury to his neck. Which specific spinal cord region injury is primarily responsible for his upper extremity deficits?

. Medial fibers of the lateral corticospinal tract
. Lateral fibers of the lateral corticospinal tract
. Anterior horn cells
. Dorsal columns
. Anterior spinothalamic tract

Correct Answer & Explanation

. Medial fibers of the lateral corticospinal tract

Explanation

Central cord syndrome preferentially affects the medial fibers of the lateral corticospinal tract. The cervical motor fibers are located medially, while thoracic and lumbar fibers are located laterally, resulting in upper extremity weakness being more profound than lower extremity weakness.

Question 5351

Topic: 6. Spine

Which of the following is the most consistent radiographic predictor of failure of nonoperative management in patients with degenerative lumbar spondylolisthesis and spinal stenosis?

. Modic Type I endplate changes
. Facet effusion greater than 1.5 mm on MRI
. Disc height loss greater than 50%
. Bridging anterior osteophyte formation
. Presence of a vacuum disc phenomenon

Correct Answer & Explanation

. Facet effusion greater than 1.5 mm on MRI

Explanation

A facet effusion of >1.5 mm on T2-weighted MRI is a highly sensitive indicator of segmental instability in degenerative lumbar spondylolisthesis. Patients with large facet effusions are significantly less likely to improve with conservative management and often require surgical fusion.

Question 5352

Topic: Cervical Spine

A 6-year-old child presents with torticollis 10 days after an upper respiratory infection. Dynamic CT scan reveals C1-C2 rotatory subluxation with 4 mm of anterior displacement of C1 on C2. According to the Fielding and Hawkins classification, what type is this and what is the status of the transverse ligament?

. Type 1 - intact transverse ligament
. Type 2 - deficient transverse ligament
. Type 3 - deficient transverse ligament and facet capsules
. Type 4 - posterior displacement of C1
. Type 1 - deficient transverse ligament

Correct Answer & Explanation

. Type 2 - deficient transverse ligament

Explanation

Fielding and Hawkins Type 2 describes anterior displacement of C1 on C2 by 3 to 5 mm, indicating a deficient transverse ligament. Type 1 has <3 mm displacement with an intact ligament, while Type 3 has >5 mm displacement, indicating failure of both the transverse ligament and secondary stabilizers.

Question 5353

Topic: 6. Spine

Which of the following clinical findings has the highest sensitivity for the diagnosis of cauda equina syndrome?

. Saddle anesthesia
. Bilateral sciatica
. Urinary retention
. Fecal incontinence
. Lower extremity motor weakness

Correct Answer & Explanation

. Urinary retention

Explanation

Urinary retention is the most consistent and sensitive early clinical sign of cauda equina syndrome, present in up to 90% of cases. The absence of urinary retention (e.g., normal post-void residual) makes the diagnosis of cauda equina syndrome highly unlikely.

Question 5354

Topic: 6. Spine

A 20-year-old male presents with slowly progressive, unilateral upper extremity weakness and atrophy involving the hand and forearm, sparing the brachioradialis. MRI of the cervical spine with neck flexion reveals anterior displacement of the posterior dura compressing the cervical cord. What is the most likely diagnosis?

. Amyotrophic lateral sclerosis
. Hirayama disease
. Syringomyelia
. Cervical spondylotic myelopathy
. Parsonage-Turner syndrome

Correct Answer & Explanation

. Hirayama disease

Explanation

Hirayama disease is a juvenile muscular atrophy of the distal upper extremity caused by dynamic compression of the lower cervical cord during neck flexion. The classic MRI finding is anterior displacement of the posterior dura on dynamic flexion imaging.

Question 5355

Topic: 6. Spine

According to the Levine and Edwards classification of traumatic spondylolisthesis of the axis (Hangman's fracture), what is the mechanism of injury and recommended treatment for a Type IIA fracture?

. Hyperextension and axial loading - halo vest in extension
. Flexion and distraction - halo vest with slight extension and compression
. Hyperextension and axial loading - rigid cervical collar
. Flexion and compression - surgical stabilization
. Hyperextension and distraction - rigid cervical collar

Correct Answer & Explanation

. Flexion and distraction - halo vest with slight extension and compression

Explanation

Type IIA Hangman's fractures occur via a flexion-distraction mechanism, resulting in severe angular deformity with minimal anterior translation. Traction is strictly contraindicated as it worsens the deformity; treatment requires a halo vest applied with slight extension and compression.

Question 5356

Topic: 6. Spine

Which of the following intraoperative factors is most strongly associated with the development of ischemic optic neuropathy following posterior instrumented spinal fusion?

. Prone positioning with direct ocular pressure
. Prolonged operative time and large estimated blood loss
. Use of controlled hypotensive anesthesia
. History of open angle glaucoma
. Male sex and obesity

Correct Answer & Explanation

. Prolonged operative time and large estimated blood loss

Explanation

Ischemic optic neuropathy is the most common cause of post-operative visual loss after complex spine surgery. Independent risk factors include prolonged operative time, large estimated blood loss, prone positioning, and obesity. Direct ocular pressure causes central retinal artery occlusion, not ischemic optic neuropathy.

Question 5357

Topic: Thoracolumbar Spine & Deformity

In the preoperative planning for adult spinal deformity correction, which of the following formulas represents the normal morphological relationship between Pelvic Incidence (PI), Sacral Slope (SS), and Pelvic Tilt (PT)?

. PI = PT - SS
. PI = PT + SS
. PT = PI + SS
. SS = PI + PT
. PI = (PT + SS) / 2

Correct Answer & Explanation

. PI = PT + SS

Explanation

Pelvic incidence (PI) is a fixed morphological parameter representing the algebraic sum of pelvic tilt (PT) and sacral slope (SS). It dictates the required lumbar lordosis to achieve sagittal balance, with the relationship defined by the formula PI = PT + SS.

Question 5358

Topic: 6. Spine

A 24-year-old male sustains a bony flexion-distraction injury (Chance fracture) of L2 in a motor vehicle collision. Neurologic examination is intact. What is the most appropriate initial management?

. Nonoperative management in a TLSO
. Short-segment posterior spinal fusion
. Anterior lumbar interbody fusion
. Laminectomy and posterior fusion
. Vertebroplasty

Correct Answer & Explanation

. Nonoperative management in a TLSO

Explanation

Bony flexion-distraction (Chance) fractures without neurologic deficit have high healing potential and can be managed safely with a TLSO or hyperextension cast. Ligamentous variants, however, have poor healing potential and typically require surgical stabilization.

Question 5359

Topic: 6. Spine

A 55-year-old diabetic patient presents with back pain, fever, and progressive lower extremity weakness. MRI confirms a large dorsal epidural abscess at T8-T10. Which of the following factors most strongly indicates the need for emergent surgical decompression rather than medical management alone?

. Complete neurologic deficit for over 72 hours
. Positive blood cultures for MRSA
. New-onset or progressive lower extremity paresis
. CRP greater than 150 mg/L
. Presence of severe axial back pain

Correct Answer & Explanation

. New-onset or progressive lower extremity paresis

Explanation

New-onset or progressive neurologic deficit is the primary and absolute indication for emergent surgical decompression in spinal epidural abscess. Patients with complete paralysis lasting more than 48-72 hours often have irreversible damage, and isolated medical management may be considered if surgery carries prohibitive risks.

Question 5360

Topic: 6. Spine

A patient presents with severe right-sided anterior thigh pain, weakness in knee extension, and a diminished right patellar reflex. MRI of the lumbar spine reveals a far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L4

Explanation

A far lateral (extraforaminal) disc herniation compresses the exiting nerve root at the same level. Therefore, an L4-L5 far lateral herniation compresses the L4 root, leading to anterior thigh pain and a diminished patellar reflex.

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