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6. Spine MCQs

Practice Set 321 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 6401

Topic: 6. Spine

A 68-year-old man presents with bilateral leg pain, heaviness, and cramping that predictably worsens with walking. Which of the following historical findings most reliably helps to differentiate neurogenic claudication (due to lumbar spinal stenosis) from vascular claudication?

. Pain is rapidly relieved simply by standing still
. Pain is relieved by sitting down or leaning forward over a shopping cart
. Symmetric diminishment of dorsalis pedis pulses
. Presence of a distal stocking-glove sensory loss
. Pain that exclusively radiates down the anterior aspect of the thigh

Correct Answer & Explanation

. Pain is rapidly relieved simply by standing still

Explanation

Neurogenic claudication is exacerbated by lumbar extension (which decreases the cross-sectional area of the spinal canal) and relieved by lumbar flexion, such as sitting or leaning forward (the 'shopping cart sign'). Vascular claudication is related to muscle ischemia during activity and is typically relieved rapidly by simply stopping the activity (standing still), without requiring a change in spine posture.

Question 6402

Topic: 6. Spine

Ossification of the posterior longitudinal ligament (OPLL) is a frequent cause of cervical myelopathy, particularly in East Asian populations. Which of the following genes has been most strongly associated with the pathogenesis of OPLL?

. COL1A1
. FGFR3
. ENPP1
. FBN1
. COMP

Correct Answer & Explanation

. COL1A1

Explanation

Mutations and polymorphisms in the ENPP1 (ectonucleotide pyrophosphatase/phosphodiesterase 1) gene have been strongly linked to the development of OPLL. ENPP1 is a key regulator of bone mineralization and inorganic pyrophosphate levels; altered expression contributes to the ectopic ossification seen in OPLL.

Question 6403

Topic: 6. Spine

A 68-year-old man presents with bilateral leg pain and fatigue when walking. He notes the symptoms resolve quickly when he sits down or leans over a shopping cart. To formally differentiate neurogenic claudication from vascular claudication, a bicycle test (van Gelderen test) is performed. Which outcome is characteristic of neurogenic claudication secondary to lumbar spinal stenosis?

. Pain occurs quickly during both upright and flexed pedaling
. Pain occurs during upright pedaling but is relieved or delayed during flexed pedaling
. Pain occurs during flexed pedaling but is relieved during upright pedaling
. No pain occurs during pedaling regardless of posture
. Pain occurs only when pedaling resistance is increased, regardless of posture

Correct Answer & Explanation

. Pain occurs quickly during both upright and flexed pedaling

Explanation

In the van Gelderen bicycle test, a patient with neurogenic claudication can pedal longer and with less leg pain when the lumbar spine is flexed (leaning forward), because this posture increases the cross-sectional area of the spinal canal and neural foramina. In contrast, patients with vascular claudication experience ischemia-induced pain based on muscle work, regardless of spinal posture.

Question 6404

Topic: 6. Spine

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

. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C5

Explanation

The C6 nerve root provides motor innervation for wrist extension and elbow flexion (along with C5), mediates the brachioradialis reflex, and supplies sensation to the radial aspect of the forearm, thumb, and index finger. A C5 radiculopathy affects shoulder abduction and the biceps reflex; C7 affects triceps and wrist flexion; C8 affects finger flexion; and T1 affects finger abduction.

Question 6405

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female gymnast presents with progressive lower back pain. Radiographs demonstrate an isthmic spondylolisthesis at L5-S1 with 60% anterior translation of L5 on S1. According to the Meyerding classification, what grade is this slip, and what is the generally recommended definitive surgical management?
. Grade II; TLSO bracing
. Grade III; pars interarticularis repair (Buck's procedure)
. Grade III; L5-S1 fusion
. Grade IV; TLSO bracing
. Grade IV; L5-S1 fusion

Correct Answer & Explanation

. Grade III; L5-S1 fusion

Explanation

The Meyerding classification grades the degree of anterior translation: Grade I (0-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (>100% or spondyloptosis). A 60% slip is Grade III. High-grade slips (III, IV, V) in symptomatic adolescents are generally unstable and require stabilization via fusion (usually L5-S1 or L4-S1 with instrumentation). Pars repairs (e.g., Buck's, Scott wiring) are reserved for symptomatic Grade I slips or spondylolysis without significant slip.

Question 6406

Topic: 6. Spine

In a patient presenting with suspected cauda equina syndrome secondary to a massive L4-L5 disc herniation, which urodynamic finding is most characteristic of the resulting neurogenic bladder?

. Detrusor hyperreflexia with high voiding pressures
. Detrusor areflexia with overflow incontinence
. Detrusor-sphincter dyssynergia
. Normal detrusor function with isolated external sphincter weakness
. Decreased bladder compliance with elevated post-void residual < 50 mL

Correct Answer & Explanation

. Detrusor hyperreflexia with high voiding pressures

Explanation

Cauda equina syndrome causes compression of the lumbosacral nerve roots below the conus medullaris, constituting a lower motor neuron (LMN) lesion. This disruption of the parasympathetic outflow (S2-S4) to the bladder results in a flaccid, areflexic bladder (detrusor areflexia). Consequently, the bladder fails to contract, leading to urinary retention, large volumes, and eventually overflow incontinence. Hyperreflexia and dyssynergia are characteristics of upper motor neuron (UMN) lesions (above the conus).

Question 6407

Topic: 6. Spine

A 45-year-old man presents with right lower extremity weakness and radicular pain radiating to the dorsum of his foot following heavy lifting. MRI reveals a massive posterolateral disc herniation at the L4-L5 level. Which of the following physical examination findings is most likely to be present?

. Diminished patellar tendon reflex
. Weakness in ankle plantarflexion
. Weakness in extensor hallucis longus
. Numbness over the medial malleolus
. Weakness in hip flexion

Correct Answer & Explanation

. Diminished patellar tendon reflex

Explanation

A posterolateral disc herniation at the L4-L5 level most commonly compresses the traversing L5 nerve root. L5 radiculopathy typically presents with weakness in the extensor hallucis longus (EHL) and altered sensation over the first dorsal web space.

Question 6408

Topic: 6. Spine

A 68-year-old male with a history of a lumbar spinal fusion from L2 to the pelvis is planned for a primary total hip arthroplasty (THA). How does this prior spinal fusion affect normal spinopelvic biomechanics during the transition from standing to sitting, and how should the surgeon adjust the acetabular component positioning?

. Decreased posterior pelvic tilt; the cup should be placed with increased anteversion.
. Increased posterior pelvic tilt; the cup should be placed with decreased anteversion.
. Decreased anterior pelvic tilt; the cup should be placed with increased inclination.
. Increased anterior pelvic tilt; the cup should be placed with decreased inclination.
. No change in pelvic tilt; the cup should be placed in the standard safe zone.

Correct Answer & Explanation

. Decreased posterior pelvic tilt; the cup should be placed with increased anteversion.

Explanation

In a normal spinopelvic relationship, transitioning from standing to sitting causes the lumbar spine to flex and the pelvis to tilt posteriorly. This posterior tilt functionally increases acetabular anteversion, allowing clearance for the proximal femur during hip flexion. A patient with a fused lumbar spine to the pelvis has a stiff spinopelvic junction and cannot tilt the pelvis posteriorly when sitting. To compensate for this lack of functional anteversion and prevent anterior impingement/posterior dislocation, the surgeon must place the acetabular component in greater structural anteversion.

Question 6409

Topic: 6. Spine

A 45-year-old male complains of neck pain radiating down his right arm, with weakness in elbow flexion and wrist extension. His brachioradialis reflex is diminished. Which cervical nerve root is most likely compressed?

. C4
. C5
. C6
. C7
. C8

Correct Answer & Explanation

. C4

Explanation

C6 radiculopathy typically presents with weakness in wrist extension (extensor carpi radialis longus/brevis) and elbow flexion (biceps/brachioradialis), with sensory changes in the thumb and radial aspect of the forearm. The brachioradialis reflex is primarily mediated by the C6 nerve root.

Question 6410

Topic: 6. Spine

A 65-year-old female presents with neurogenic claudication secondary to lumbar spinal stenosis. She states her leg pain improves when she leans forward on a shopping cart. Which of the following anatomical changes explains this phenomenon?

. Decreased bulging of the ligamentum flavum and increased foraminal area
. Increased bulging of the intervertebral disc and decreased canal diameter
. Tensioning of the posterior longitudinal ligament causing central compression
. Relaxation of the psoas muscle reducing traction on the lumbar plexus
. Widening of the facet joints decreasing capsular tension

Correct Answer & Explanation

. Decreased bulging of the ligamentum flavum and increased foraminal area

Explanation

Lumbar flexion increases the anterior-posterior diameter of the spinal canal and the cross-sectional area of the neural foramina. It stretches the ligamentum flavum, reducing its inward buckling into the spinal canal, thereby temporarily relieving mechanical compression on the cauda equina and nerve roots.

Question 6411

Topic: 6. Spine

During the physical examination of a 65-year-old man with neck pain and gait clumsiness, the examiner flicks the distal phalanx of the middle finger, resulting in reflex flexion of the thumb and index finger. This clinical sign is mediated by which of the following nerve roots?

. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C5

Explanation

The Hoffmann sign indicates an upper motor neuron lesion in the cervical spine (cervical myelopathy). The reflex arc itself is mediated via the C8 nerve root, which innervates the long finger flexors.

Question 6412

Topic: 6. Spine

According to the Denis three-column theory of the spine, the middle column comprises which of the following structures?

. Anterior half of the vertebral body and ALL
. Posterior half of the vertebral body and PLL
. Pedicles and facet joints
. Lamina and spinous processes
. Ligamentum flavum and interspinous ligaments

Correct Answer & Explanation

. Anterior half of the vertebral body and ALL

Explanation

In the Denis three-column concept, the middle column consists of the posterior half of the vertebral body, posterior half of the annulus fibrosus, and the posterior longitudinal ligament (PLL). A burst fracture involves failure of both the anterior and middle columns.

Question 6413

Topic: 6. Spine

A 42-year-old man presents to the emergency department with severe lower back pain, bilateral sciatica, and saddle anesthesia. He reports difficulty initiating urination. Which of the following is the most appropriate next step in management?

. Schedule an outpatient MRI
. Prescribe oral corticosteroids and discharge
. Perform a post-void residual volume ultrasound and emergent MRI
. Administer epidural steroid injection
. Recommend 48 hours of strict bed rest

Correct Answer & Explanation

. Schedule an outpatient MRI

Explanation

The patient exhibits classic symptoms of Cauda Equina Syndrome (CES). A post-void residual (PVR) ultrasound is a rapid test to assess for urinary retention, and an emergent MRI is strictly required to confirm the diagnosis prior to urgent surgical decompression.

Question 6414

Topic: 6. Spine

A 40-year-old male presents with severe neck pain and bilateral upper extremity weakness after a diving accident. Lateral radiographs show an anterior translation of C5 on C6 by 60%. Which of the following is the most appropriate next step in management for this awake, alert, and cooperative patient?

. Immediate anterior cervical discectomy and fusion
. Immediate posterior cervical fusion
. Closed reduction with cranial tongs and serial radiographs
. MRI of the cervical spine prior to any reduction attempts
. Application of a halo vest

Correct Answer & Explanation

. Immediate anterior cervical discectomy and fusion

Explanation

In an awake, alert, and cooperative patient with a cervical facet dislocation and neurologic deficit, urgent closed reduction using cranial tongs is indicated. MRI is not required prior to closed reduction in a cooperative patient who can participate in serial neurologic exams. MRI is required if the patient is unexaminable (e.g., comatose) or fails closed reduction attempts, to evaluate for an extruded disc.

Question 6415

Topic: 6. Spine

A 65-year-old male presents with deteriorating handwriting, dropping objects, and an unsteady, broad-based gait. Physical examination reveals a positive Hoffmann sign and an inverted brachioradialis reflex. MRI of the cervical spine shows severe central canal stenosis at the C5-C6 level. On motor examination, which of the following deficits is most likely to be observed due to specific nerve root compression at this level?

. Weakness in shoulder abduction
. Weakness in elbow extension
. Weakness in wrist extension
. Weakness in finger abduction
. Weakness in thumb interphalangeal joint flexion

Correct Answer & Explanation

. Weakness in shoulder abduction

Explanation

The patient has cervical spondylotic myelopathy. The C5-C6 intervertebral disc level corresponds to the exiting C6 nerve root. The C6 nerve root innervates the wrist extensors (extensor carpi radialis longus and brevis) and contributes to elbow flexion (biceps, brachialis). Weakness in elbow extension would be C7 (C6-C7 level). Shoulder abduction is C5. Finger abduction is T1. Thumb IP joint flexion is C8.

Question 6416

Topic: Thoracolumbar Spine & Deformity
A 15-year-old female gymnast presents with insidious onset of mechanical low back pain. Standing lateral radiographs reveal a Grade 2 L5-S1 spondylolisthesis. According to the Wiltse classification of spondylolisthesis, this patient most likely has a Type II slip. What is the primary underlying anatomic pathomechanism for a Wiltse Type II spondylolisthesis?
. Congenital dysplasia of the L5-S1 facet joints
. A defect or stress fracture in the pars interarticularis
. Degenerative arthrosis of the facet joints and intervertebral disc
. An acute traumatic fracture of the pedicle or lamina
. Destruction of the posterior elements by a primary bone tumor

Correct Answer & Explanation

. A defect or stress fracture in the pars interarticularis

Explanation

The Wiltse classification categorizes spondylolisthesis by etiology. Type I is Dysplastic (congenital abnormalities of the upper sacrum or L5 arch). Type II is Isthmic, caused by a defect (often a stress fracture from repetitive hyperextension, classic in gymnasts) in the pars interarticularis. Type III is Degenerative (older adults, intact pars). Type IV is Traumatic (acute fracture of the bony hook other than the pars). Type V is Pathologic (tumor/infection).

Question 6417

Topic: 6. Spine

A 68-year-old male presents with bilateral lower extremity radicular pain that worsens with walking. He notes relief when leaning forward on a shopping cart. Which of the following anatomical changes dynamically increases the cross-sectional area of the spinal canal and neural foramina in this position?

. Unbuckling of the ligamentum flavum
. Decreased tension on the posterior longitudinal ligament
. Increased bulging of the intervertebral discs
. Flattening of the anterior longitudinal ligament
. Contraction of the multifidus muscles

Correct Answer & Explanation

. Unbuckling of the ligamentum flavum

Explanation

Flexion of the lumbar spine causes the ligamentum flavum to stretch and "unbuckle." This increases the cross-sectional area of the spinal canal and neural foramina, relieving symptoms of neurogenic claudication.

Question 6418

Topic: 6. Spine

A 50-year-old male is involved in a motor vehicle accident. CT reveals a burst fracture of C5 with 60% canal compromise. He has 0/5 strength in bilateral extremities and absent rectal tone. The bulbocavernosus reflex is absent. Which of the following terms best describes his current neurological state?

. Complete spinal cord injury
. Anterior cord syndrome
. Central cord syndrome
. Spinal shock
. Neurogenic shock

Correct Answer & Explanation

. Complete spinal cord injury

Explanation

The absence of the bulbocavernosus reflex in the immediate post-traumatic period defines spinal shock, a state of transient physiological suppression of cord function. A complete spinal cord injury cannot be definitively diagnosed until spinal shock resolves.

Question 6419

Topic: 6. Spine

A 65-year-old male presents with progressive hand clumsiness and frequent falls. Examination demonstrates a positive Hoffmann sign bilaterally and inverted supinator reflexes. MRI reveals severe cervical stenosis at C4-C5 and C5-C6 with cord signal change. Which of the following physical exam findings is most specific for cervical myelopathy?

. Biceps reflex 3+
. Hoffmann sign
. Babinski sign
. Inverted supinator sign
. Sustained clonus

Correct Answer & Explanation

. Biceps reflex 3+

Explanation

The inverted supinator reflex is highly specific for cervical myelopathy. While Hoffmann and Babinski signs indicate upper motor neuron lesions, they are less specific to the cervical spine compared to the inverted supinator sign which localizes to C5-C6.

Question 6420

Topic: 6. Spine

A 72-year-old man presents with bilateral leg heaviness and pain that worsens with walking upright and improves when leaning forward on a shopping cart. Examination reveals normal distal pulses. Which of the following pathological changes is the primary driver of central canal stenosis in this condition?

. Hypertrophy of the ligamentum flavum
. Ossification of the posterior longitudinal ligament
. Synovial cyst formation at the facet joint
. Spondylolysis of the pars interarticularis
. Herniation of the nucleus pulposus

Correct Answer & Explanation

. Hypertrophy of the ligamentum flavum

Explanation

This patient has classic symptoms of neurogenic claudication due to lumbar spinal stenosis. The most common anatomical causes of central canal stenosis are facet arthropathy, disc space narrowing, and hypertrophy or buckling of the ligamentum flavum.

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