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6. Spine MCQs

Practice Set 41 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 801

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female presents with severe mechanical back pain and a wide-based waddling gait. Radiographs reveal a Grade III L5-S1 isthmic spondylolisthesis with a slip angle of 55 degrees and a high pelvic incidence. What is the most appropriate surgical management?
. In situ posterolateral fusion of L5-S1
. Direct pars repair (e.g., Scott wiring)
. Posterior spinal fusion of L4-S1 with partial or complete reduction
. Anterior lumbar interbody fusion (ALIF) alone

Correct Answer & Explanation

. Posterior spinal fusion of L4-S1 with partial or complete reduction

Explanation

High-grade dysplastic or isthmic spondylolisthesis in adolescents with a high slip angle typically requires reduction and fusion extending to L4 to restore sagittal balance and prevent progressive deformity.

Question 802

Topic: 6. Spine

A 50-year-old male with long-standing ankylosing spondylitis presents to the emergency department after a minor ground-level fall. He complains of new, severe lower cervical neck pain. Plain radiographs of the cervical spine show no obvious fracture. What is the most appropriate next step in management?

. Reassurance and discharge with NSAIDs
. CT scan or MRI of the entire spine
. Flexion-extension cervical radiographs
. Technetium-99m bone scan

Correct Answer & Explanation

. Reassurance and discharge with NSAIDs

Explanation

Patients with ankylosing spondylitis are at extremely high risk for unstable, occult spinal fractures even after minor trauma. Advanced imaging (CT or MRI) of the entire spine is mandatory if plain films are negative.

Question 803

Topic: 6. Spine

A 68-year-old male presents with bilateral neurogenic claudication. Based on a typical sagittal MRI of the lumbar spine showing central canal stenosis

, which of the following structures is the primary contributor to dorsal compression of the thecal sac?

. Anterior longitudinal ligament
. Posterior longitudinal ligament
. Ligamentum flavum
. Annulus fibrosus

Correct Answer & Explanation

. Ligamentum flavum

Explanation

In degenerative central canal stenosis, dorsal compression of the thecal sac is primarily caused by buckling and hypertrophy of the ligamentum flavum, often combined with facet arthropathy.

Question 804

Topic: 6. Spine

A 42-year-old female presents with severe acute low back pain radiating to both legs. Which of the following is considered the most sensitive early clinical symptom or sign of cauda equina syndrome?

. Bilateral lower extremity weakness
. Loss of Achilles tendon reflexes
. Urinary retention
. Decreased anal sphincter tone

Correct Answer & Explanation

. Urinary retention

Explanation

Urinary retention is the most sensitive symptom of cauda equina syndrome, with a sensitivity of approximately 90%. An intact post-void residual effectively rules out early cauda equina compression.

Question 805

Topic: Cervical Spine

An 82-year-old male with severe COPD and coronary artery disease presents after a fall. Imaging reveals a non-displaced Type II odontoid fracture. Which of the following is the most appropriate initial management?

. Halo vest orthosis
. Rigid cervical collar
. Posterior C1-C2 fusion
. Anterior odontoid screw fixation

Correct Answer & Explanation

. Rigid cervical collar

Explanation

In elderly patients (octogenarians), halo vest placement is associated with a high rate of morbidity and mortality. A rigid cervical collar is the safest initial non-operative treatment for non-displaced or stable patterns in patients with significant comorbidities.

Question 806

Topic: Thoracolumbar Spine & Deformity

According to the Wiltse classification of spondylolisthesis, Type 1 (Dysplastic) is most commonly associated with which of the following anatomic abnormalities?

. A defect in the pars interarticularis
. An intact but elongated pars interarticularis
. Congenital deficiency of the superior S1 facet and inferior L5 facet
. Degenerative arthropathy of the facet joints without an osseous defect

Correct Answer & Explanation

. Congenital deficiency of the superior S1 facet and inferior L5 facet

Explanation

Dysplastic (Type 1) spondylolisthesis is caused by congenital abnormalities of the upper sacrum or the arch of L5, primarily involving deficient or abnormally oriented facet joints that allow forward slippage.

Question 807

Topic: 6. Spine

A comatose 25-year-old male is brought to the trauma bay after a high-speed motor vehicle collision. Radiographs

reveal a bilateral C5-C6 facet dislocation. What is the most appropriate next step in management prior to definitive reduction?

. Immediate anterior cervical discectomy and fusion
. Closed cranial traction and reduction in the emergency department
. MRI of the cervical spine
. Posterior cervical instrumented fusion

Correct Answer & Explanation

. MRI of the cervical spine

Explanation

In a patient who is unexaminable (comatose) with a cervical facet dislocation, an MRI must be obtained prior to closed or open reduction to rule out a large herniated disc that could cause iatrogenic spinal cord injury upon reduction.

Question 808

Topic: 6. Spine

During a posterior lumbar spinal fusion, the surgeon prepares for pedicle screw insertion using the intersection technique. The typical entry point for a lumbar pedicle screw is located at the intersection of the transverse process and which other anatomic landmark?

. The inferior border of the inferior articular process
. The lateral border of the superior articular process
. The base of the spinous process
. The center of the mamillary process

Correct Answer & Explanation

. The lateral border of the superior articular process

Explanation

In the lumbar spine, the pedicle starting point is typically at the intersection of a line bisecting the transverse process and a vertical line along the lateral border of the superior articular process/facet.

Question 809

Topic: 6. Spine

A 40-year-old patient undergoes emergency laminectomy and discectomy for cauda equina syndrome secondary to a massive L4-L5 disc herniation. Postoperatively, what is the most common long-term persistent deficit in these patients?

. Dense motor weakness in ankle dorsiflexion
. Sexual, bowel, and bladder dysfunction
. Incapacitating mechanical back pain
. Lower extremity spasticity and clonus

Correct Answer & Explanation

. Sexual, bowel, and bladder dysfunction

Explanation

Even with prompt surgical decompression, a significant percentage of patients with cauda equina syndrome experience long-term residual genitourinary, sexual, and bowel dysfunction due to irreversible damage to the sacral nerve roots.

Question 810

Topic: 6. Spine

A 30-year-old male presents after a diving accident. Imaging

demonstrates a traumatic spondylolisthesis of the axis (Hangman's fracture). What is the classic mechanism of injury for this fracture pattern?

. Hyperflexion and compression
. Hyperextension and axial loading
. Distraction and extension
. Lateral bending and rotation

Correct Answer & Explanation

. Hyperextension and axial loading

Explanation

A traumatic spondylolisthesis of the axis (Hangman's fracture) typically occurs via a hyperextension and axial loading mechanism, leading to bilateral fractures through the pars interarticularis of C2.

Question 811

Topic: Thoracolumbar Spine & Deformity

In the assessment of adult spinal deformity, Pelvic Incidence (PI) is a key morphological parameter that is fixed for each individual after skeletal maturity. It is mathematically defined as the sum of which two parameters?

. Pelvic tilt and lumbar lordosis
. Pelvic tilt and sacral slope
. Lumbar lordosis and sacral slope
. Thoracic kyphosis and lumbar lordosis

Correct Answer & Explanation

. Pelvic tilt and sacral slope

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter defined as the sum of the pelvic tilt (PT) and the sacral slope (SS). Thus, PI = PT + SS.

Question 812

Topic: Thoracolumbar Spine & Deformity

According to the Thoracolumbar Injury Classification and Severity Score (TLICS), which of the following findings contributes the most points towards the indication for surgical intervention?

. Burst fracture morphology
. Complete neurologic deficit
. Suspected posterior ligamentous complex injury
. Incomplete neurologic deficit

Correct Answer & Explanation

. Incomplete neurologic deficit

Explanation

In the TLICS system, an incomplete neurologic deficit awards the highest points (3 points). Complete deficit is 2 points, burst morphology is 2 points, and suspected PLC injury is 2 points.

Question 813

Topic: 6. Spine

The Nurick classification for cervical spondylotic myelopathy is heavily utilized in clinical assessment. It is primarily based on which of the following patient features?

. Deterioration of fine motor skills in the hands
. Degree of bowel and bladder dysfunction
. Ambulatory status and gait impairment
. Presence of pathologic upper motor neuron reflexes

Correct Answer & Explanation

. Ambulatory status and gait impairment

Explanation

The Nurick grading scale focuses specifically on ambulatory status and gait impairment, ranging from Grade 0 (no root or cord signs) to Grade 5 (chair-bound or bedridden).

Question 814

Topic: 6. Spine

Following a rigid L4-S1 posterior spinal fusion, the adjacent L3-L4 segment is at risk for accelerated degeneration (adjacent segment disease). Which biomechanical alteration primarily occurs at this adjacent level?

. Decreased intradiscal pressure
. Increased segmental mobility and mechanical stress
. Ossification of the anterior longitudinal ligament
. Spontaneous interbody fusion

Correct Answer & Explanation

. Increased segmental mobility and mechanical stress

Explanation

Fusion restricts motion at the operated levels, leading to compensatory increased segmental mobility, mechanical stress, and elevated intradiscal pressure at the adjacent unfused segments, thereby accelerating degeneration.

Question 815

Topic: 6. Spine

A 60-year-old diabetic male with an L3-L4 pyogenic spondylodiscitis caused by Staphylococcus aureus has been on targeted IV antibiotics for 2 days. What is the primary absolute indication for urgent surgical decompression?

. Persistent back pain and low-grade fevers
. Development of an epidural abscess causing progressive neurologic deficit
. Persistently elevated ESR and CRP
. Presence of Modic Type 1 changes on MRI

Correct Answer & Explanation

. Development of an epidural abscess causing progressive neurologic deficit

Explanation

While medical management with IV antibiotics is the first line for spondylodiscitis, the development of an epidural abscess with progressive neurologic deficit is an absolute indication for urgent surgical decompression.

Question 816

Topic: 6. Spine

A 72-year-old male with severe pre-existing cervical spondylosis presents after a fall resulting in a hyperextension injury to his neck

. Examination reveals profound motor weakness in his upper extremities with relatively preserved strength in his lower extremities. What is the most likely diagnosis?

. Anterior cord syndrome
. Brown-Sequard syndrome
. Central cord syndrome
. Posterior cord syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome classically occurs in elderly patients with pre-existing cervical stenosis who sustain a hyperextension injury. It presents with disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 817

Topic: 6. Spine

When evaluating a patient with lower extremity claudication symptoms, which of the following historical findings is most indicative of neurogenic claudication (due to spinal stenosis) rather than vascular claudication?

. Pain that is relieved promptly by simply standing still
. Pain that worsens significantly when walking uphill
. Pain that is relieved when leaning forward or sitting
. Diminished distal pulses with atrophic skin changes

Correct Answer & Explanation

. Pain that is relieved when leaning forward or sitting

Explanation

Neurogenic claudication is characteristically relieved by lumbar flexion (leaning forward on a shopping cart or sitting), which opens the spinal canal and neuroforamina. Vascular claudication is relieved simply by resting (standing still) and worsens with increased metabolic demand like walking uphill.

Question 818

Topic: 6. Spine

A 28-year-old woman complains of pain and numbness in her lower legs bilaterally for approximately 2 months following strenuous moving of furniture. She now states that she has not voided in the past 48 hours and that her abdomen area is markedly distended. What diagnostic test must be performed in order to support the suspected diagnosis:

. Voiding cystourethrogram
. Magnetic resonance imaging of the lumbosacral spine
. Posteroanterior and lateral plain radiographs of the lumbar spine
. Spinal puncture to rule out infection
. Electromyography of the lower extremities

Correct Answer & Explanation

. Magnetic resonance imaging of the lumbosacral spine

Explanation

Based on history and physical examination, the suspected diagnosis is cauda equina syndrome. This potential surgical emergency requires immediate spinal imaging. A magnetic resonance imaging of the lumbosacral spine is the most appropriate test.

Question 819

Topic: 6. Spine

What is the most common sequence of steps performed during a midline open disectomy in the treatment and excision of a herniated posterolateral lumbar disk:

. The paraspinal musculature is stripped from the lamina of the vertebra, the ligamentum flavum is excised, portions of the superior and inferior lamina are removed, the nerve root and dural sac is retracted, and the disk herniation is excised.
. The ligamentum flavum is excised, the paraspinal musculature is stripped from the lamina of the vertebra, portions of the superior and inferior lamina are removed, the nerve root and dural sac is retracted, and the disk herniation is excised.
. The ligamentum flavum is excised, the paraspinal musculature is stripped from the lamina of the vertebra, the nerve root and dural sac is retracted, portions of the superior and inferior lamina are removed, and the disk herniation is excised.
. The paraspinal musculature is stripped from the lamina of the vertebra, the disk herniation is excised, the ligamentum flavum is excised, the nerve root and dural sac is retracted, and portions of the superior and inferior lamina are removed.
. Ligamentum flavum is excised, the disk herniation is excised the paraspinal musculature is stripped from the lamina of the vertebra, the nerve root and dural sac is retracted, and portions of the superior and inferior lamina are removed.

Correct Answer & Explanation

. The paraspinal musculature is stripped from the lamina of the vertebra, the ligamentum flavum is excised, portions of the superior and inferior lamina are removed, the nerve root and dural sac is retracted, and the disk herniation is excised.

Explanation

The traditional surgery for the excision of a herniated posterolateral lumbar disk is by means of a midline incision. This procedure is then performed in a stepwise fashion: The paraspinal musculature is stripped from the lamina of the vertebra; the ligamentum flavum is then excised; portions of the superior and inferior lamina are removed; and the nerve root and dural sac are identified and carefully retracted. This is followed by excision of the herniated disk material and wound closure.

Question 820

Topic: 6. Spine

On physical examination, a patient with a weak extensor hallucis longus muscle might be expected to have a far-lateral disk herniation at what level in the spine:

. L2/L3
. L3/L4
. L4/L5
. L5/S1
. S1/S2

Correct Answer & Explanation

. L5/S1

Explanation

A far-lateral disk herniation in the lumbar spine often compromises the more proximal, or exiting, nerve root and not the more distal, or traversing, nerve root most typically affected in a posterolateral disk herniation. Therefore, a far-lateral disk herniation at the L5 - S1 level could irritate the L5 nerve root, which would affect the extensor hallucis longus muscle.

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