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6. Spine MCQs

Practice Set 73 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 1441

Topic: 6. Spine

A 65-year-old diabetic patient presents with severe back pain and elevated inflammatory markers. MRI confirms pyogenic spondylodiscitis at L3-L4. What is the most common causative organism for this condition?

. Streptococcus pneumoniae
. Escherichia coli
. Staphylococcus aureus
. Pseudomonas aeruginosa
. Mycobacterium tuberculosis

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is the most common causative organism in pyogenic spondylodiscitis across all patient demographics. Empiric antibiotic therapy should provide robust coverage for this pathogen.

Question 1442

Topic: Cervical Spine

A 25-year-old male is involved in a motor vehicle accident and sustains a burst fracture of the C1 ring (Jefferson fracture). Which radiographic finding best indicates incompetence of the transverse atlantal ligament?

. Prevertebral soft tissue swelling > 5mm at C2
. Combined lateral mass displacement > 6.9 mm on open-mouth odontoid view
. Atlanto-dens interval (ADI) of 2 mm
. Fracture of the anterior arch only
. Loss of cervical lordosis

Correct Answer & Explanation

. Combined lateral mass displacement > 6.9 mm on open-mouth odontoid view

Explanation

Spence's rule states that a combined lateral mass displacement of the atlas greater than 6.9 mm on an AP open-mouth radiograph indicates a rupture of the transverse atlantal ligament. This implies an unstable C1 fracture requiring rigid immobilization or surgical stabilization.

Question 1443

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female gymnast presents with chronic mechanical lower back pain. Lateral lumbar radiographs demonstrate a 60% anterior translation of L5 on S1. According to the Meyerding classification, what grade is this spondylolisthesis?
. Grade I
. Grade II
. Grade III
. Grade IV
. Grade V

Correct Answer & Explanation

. Grade III

Explanation

The Meyerding classification grades the percentage of forward slip: Grade I (0-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (>100%). A 60% slip is categorized as Grade III.

Question 1444

Topic: Cervical Spine

According to the Rule of Spence, an open-mouth odontoid radiograph showing total lateral overhang of the C1 lateral masses on C2 of greater than 6.9 mm indicates a rupture of which structure?

. Alar ligament
. Apical ligament
. Transverse atlantal ligament
. Tectorial membrane
. Posterior longitudinal ligament

Correct Answer & Explanation

. Transverse atlantal ligament

Explanation

A combined lateral overhang of the C1 lateral masses on C2 exceeding 6.9 mm (or 8.1 mm accounting for radiographic magnification) suggests a rupture of the Transverse Atlantal Ligament (TAL). This represents an unstable Jefferson fracture variant requiring rigid stabilization.

Question 1445

Topic: 6. Spine

A 65-year-old male presents with a clumsy gait, dropping objects, and intrinsic hand muscle wasting. Physical exam reveals hyperreflexia in the lower extremities. Which of the following physical exam findings is highly specific for cervical spondylotic myelopathy at the C5-C6 level?

. Lhermitte's sign
. Inverted supinator reflex
. Spurling's test
. Waddell's signs
. Tinel's sign at the wrist

Correct Answer & Explanation

. Inverted supinator reflex

Explanation

The inverted supinator (brachioradialis) reflex involves paradoxical finger flexion or elbow extension when tapping the brachioradialis tendon. It is a highly specific upper motor neuron sign indicative of cervical myelopathy at C5-C6.

Question 1446

Topic: 6. Spine

A 55-year-old male presents with right arm pain, weakness in wrist extension, and numbness in the dorsal web space between the thumb and index finger. The triceps reflex is normal, but the brachioradialis reflex is diminished. Which cervical nerve root is most likely compressed?

. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C6

Explanation

C6 radiculopathy typically presents with weakness in wrist extension and elbow flexion, diminished brachioradialis reflex, and sensory changes in the thumb and index finger. C7 radiculopathy would typically involve triceps weakness and a diminished triceps reflex.

Question 1447

Topic: Thoracolumbar Spine & Deformity

A 6-year-old child presents with a grade IV L5-S1 isthmic spondylolisthesis. The child has a severe waddling gait and hamstring tightness but no focal neurologic deficits. What is the most appropriate surgical treatment?

. Pars repair with wiring
. L5-S1 in situ posterolateral fusion
. L5-S1 posterior lumbar interbody fusion (PLIF) with reduction
. L4-S1 posterolateral fusion with instrumented reduction
. Anterior release followed by posterior spinal fusion

Correct Answer & Explanation

. L5-S1 in situ posterolateral fusion

Explanation

For high-grade dysplastic or isthmic spondylolisthesis in children, in situ posterolateral fusion is highly successful and remains the gold standard. Aggressive reduction maneuvers carry a significantly higher risk of L5 nerve root injury and are generally avoided if no focal deficits exist.

Question 1448

Topic: 6. Spine

A patient with suspected cervical spondylotic myelopathy demonstrates an inverted supinator reflex. This clinical finding is most specific for compression at which spinal cord level?

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

Correct Answer & Explanation

. C5-C6

Explanation

The inverted supinator reflex indicates a lower motor neuron lesion at C5-C6 (loss of brachioradialis reflex) and an upper motor neuron lesion below this level (hyperactive finger flexors). It is highly specific for cervical myelopathy at the C5-C6 level.

Question 1449

Topic: 6. Spine

A 70-year-old female presents with bilateral leg heaviness that worsens with walking and is relieved by leaning forward over a shopping cart. Which of the following anatomic structures is the primary contributor to dorsal compression in this classic presentation?

. Posterior longitudinal ligament
. Ligamentum flavum
. Intervertebral disc herniation
. Facet joint osteophytes
. Pedicle hypertrophy

Correct Answer & Explanation

. Ligamentum flavum

Explanation

Neurogenic claudication in central lumbar spinal stenosis is frequently driven by ligamentum flavum hypertrophy. The ligament buckles dorsally into the canal during spinal extension, increasing compression, and stretches during flexion, relieving symptoms.

Question 1450

Topic: 6. Spine

A 45-year-old male presents with severe neck pain radiating down his right arm, associated with numbness in the thumb and index finger. Examination reveals a diminished brachioradialis reflex and weakness in wrist extension. Which cervical nerve root is most likely affected?

. C4
. C5
. C6
. C7
. C8

Correct Answer & Explanation

. C6

Explanation

A C6 radiculopathy classically presents with numbness in the thumb and index finger, weakness in wrist extension and elbow flexion, and a diminished brachioradialis reflex.

Question 1451

Topic: 6. Spine

A 65-year-old patient with long-standing rheumatoid arthritis presents with progressive myelopathy. Flexion-extension radiographs reveal 9 mm of anterior atlantoaxial subluxation without cranial settling. What is the most appropriate surgical management?

. C1-C2 posterior fusion
. Occipitocervical fusion
. Anterior odontoid screw fixation
. Cervical laminectomy without fusion
. Transoral odontoidectomy

Correct Answer & Explanation

. C1-C2 posterior fusion

Explanation

For anterior atlantoaxial subluxation with myelopathy but without cranial settling or subaxial involvement, a C1-C2 posterior fusion is indicated. Occipitocervical fusion is reserved for cases with cranial settling.

Question 1452

Topic: 6. Spine

A 40-year-old male presents with right leg pain radiating to the dorsum of the foot and weakness in great toe extension following a paracentral disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L5

Explanation

A paracentral disc herniation in the lumbar spine typically compresses the traversing nerve root. At the L4-L5 level, the L5 nerve root is compressed, leading to weakness in extensor hallucis longus (EHL) and altered sensation on the foot's dorsum.

Question 1453

Topic: 6. Spine

A 45-year-old male presents with acute onset saddle anesthesia, bilateral sciatica, and bowel incontinence following a heavy lifting event. Which of the following is the most consistent early urodynamic finding in this condition?

. Detrusor hyperreflexia
. Decreased post-void residual volume
. Detrusor areflexia with increased post-void residual
. Urethral sphincter spasm
. Normal cystometrogram

Correct Answer & Explanation

. Detrusor areflexia with increased post-void residual

Explanation

Cauda equina syndrome typically causes a lower motor neuron lesion of the bladder, leading to detrusor areflexia and urinary retention. This manifests clinically as overflow incontinence and an increased post-void residual volume.

Question 1454

Topic: 6. Spine

A 60-year-old male presents with deteriorating fine motor skills in his hands, a broad-based gait, and hyperreflexia. Which radiographic measurement on a lateral cervical spine X-ray strongly correlates with an increased risk of cervical spondylotic myelopathy?

. Pavlov ratio of less than 0.8
. Cobb angle of 10 degrees
. Atlantodental interval of 2 mm
. Prevertebral soft tissue thickness of 5 mm at C2
. C7 plumb line passing 2 cm anterior to the S1 endplate

Correct Answer & Explanation

. Pavlov ratio of less than 0.8

Explanation

The Torg-Pavlov ratio compares the AP diameter of the spinal canal to the AP diameter of the vertebral body. A ratio of less than 0.8 indicates congenital cervical stenosis and a substantially higher risk for developing cervical myelopathy.

Question 1455

Topic: 6. Spine
A 32-year-old female sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) with severe angulation and >5 mm of translation (Levine-Edwards Type IIA). What is the mechanism of this specific fracture pattern and the appropriate initial management?
. Hyperextension and axial loading; rigid cervical collar
. Flexion-distraction; application of skeletal traction
. Flexion-distraction; halo vest placement in slight compression
. Hyperextension and axial loading; immediate anterior cervical discectomy and fusion
. Flexion-compression; application of skeletal traction

Correct Answer & Explanation

. Flexion-distraction; halo vest placement in slight compression

Explanation

A Type IIA Hangman's fracture occurs via a flexion-distraction mechanism, resulting in severe angulation with minimal initial translation that becomes highly unstable with traction. Skeletal traction is absolutely contraindicated as it exacerbates the deformity; management involves gentle reduction in slight extension and compression in a halo vest.

Question 1456

Topic: 6. Spine

A 65-year-old man presents with progressive clumsiness in his hands and a broad-based gait. Physical exam reveals a positive Hoffmann sign and hyperreflexia. Sagittal MRI shows cervical stenosis with a kyphotic alignment. Which surgical approach is most appropriate?

. Posterior laminectomy alone
. Posterior laminoplasty
. Anterior cervical discectomy and fusion (ACDF) or corpectomy
. Posterior foraminotomy
. Cervical disc arthroplasty

Correct Answer & Explanation

. Anterior cervical discectomy and fusion (ACDF) or corpectomy

Explanation

The patient has cervical spondylotic myelopathy with a kyphotic deformity. An anterior approach (ACDF or corpectomy) is indicated to decompress the spinal cord and correct the kyphosis, whereas posterior decompression alone in the setting of kyphosis can worsen the deformity and fail to relieve anterior cord tension.

Question 1457

Topic: Cervical Spine

A 45-year-old sustains a Hangman's fracture demonstrating severe angulation but minimal translation, classified as an Effendi/Levine-Edwards Type IIa. What is the appropriate initial management strategy?

. Immediate heavy cervical traction to reduce the angulation
. Gentle compression in extension with a halo vest, avoiding traction
. Halo vest placement in a highly flexed position
. Immediate anterior cervical discectomy and fusion
. C1-C2 posterior transarticular screw fixation

Correct Answer & Explanation

. Gentle compression in extension with a halo vest, avoiding traction

Explanation

Type IIa Hangman's fractures involve an atypical flexion-distraction injury. Cervical traction is contraindicated as it will worsen the deformity; management requires gentle compression and extension in a halo vest.

Question 1458

Topic: 6. Spine

A 55-year-old diabetic patient presents with severe back pain, fever, and progressive lower extremity weakness. MRI reveals a spinal epidural abscess. What is the most common causative organism?

. Staphylococcus epidermidis
. Streptococcus pneumoniae
. Staphylococcus aureus
. Pseudomonas aeruginosa
. Mycobacterium tuberculosis

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is by far the most common organism responsible for spinal epidural abscesses and vertebral osteomyelitis in the general population.

Question 1459

Topic: 6. Spine



A 68-year-old male presents with neurogenic claudication. Which of the following history or physical examination findings most reliably differentiates neurogenic claudication from vascular claudication?

. Pain relief when walking uphill compared to downhill
. Absent distal pulses upon palpation
. Cramping pain in the calves that begins immediately upon exertion
. Pain that resolves immediately upon standing still
. Unilateral radicular pain distribution

Correct Answer & Explanation

. Pain relief when walking uphill compared to downhill

Explanation

Walking uphill induces lumbar flexion, which increases the spinal canal cross-sectional area and relieves symptoms in neurogenic claudication. Conversely, vascular claudication worsens with increased exertion like walking uphill and resolves quickly when the patient stands still.

Question 1460

Topic: 6. Spine

A 65-year-old man presents with bilateral leg pain exacerbated by walking and relieved by sitting and leaning forward. He reports that riding a stationary bicycle does not provoke his symptoms. What is the most likely pathophysiological mechanism of his symptoms?

. Atherosclerotic narrowing of the popliteal artery
. Hypertrophy of the ligamentum flavum
. Acute lumbar disc herniation at L4-L5
. Spondylolysis of L5
. Deep vein thrombosis

Correct Answer & Explanation

. Hypertrophy of the ligamentum flavum

Explanation

The patient's symptoms are classic for neurogenic claudication caused by lumbar spinal stenosis. Central canal narrowing is frequently due to facet arthropathy and hypertrophy of the ligamentum flavum, and symptoms are relieved by lumbar flexion (e.g., leaning forward, cycling).

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