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6. Spine MCQs

Practice Set 171 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 3401

Topic: 6. Spine

A 52-year-old man presents with acute onset, severe left-sided radiating leg pain. Physical examination reveals weakness in knee extension, an asymmetric depressed patellar tendon reflex on the left, and numbness over the medial aspect of the left lower leg. An MRI of the lumbar spine reveals a far-lateral (extraforaminal) disc herniation. At which of the following disc levels is this herniation most likely located?

. L2-L3
. L3-L4
. L4-L5
. L5-S1
. S1-S2

Correct Answer & Explanation

. L4-L5

Explanation

The patient exhibits classic signs of an L4 nerve root radiculopathy: weakness in quadriceps (knee extension), a depressed patellar reflex, and sensory deficits over the medial leg. In the lumbar spine, a typical paracentral disc herniation compresses the traversing nerve root (e.g., L4-L5 paracentral disc hits the L5 root). However, a far-lateral (foraminal/extraforaminal) disc herniation compresses the exiting nerve root at that level. Therefore, to compress the exiting L4 nerve root, the far-lateral disc herniation must be located at the L4-L5 level.

Question 3402

Topic: 6. Spine
A 35-year-old male is involved in a motor vehicle accident and sustains a traumatic spondylolisthesis of the axis (Hangman's fracture). Radiographs show a fracture through the pars interarticularis of C2 with 4 mm of translation and 12 degrees of angulation. According to the Levine and Edwards classification, what is the most appropriate initial management?
. Rigid cervical collar for 6 weeks
. Halo vest immobilization
. Anterior cervical discectomy and fusion of C2-C3
. Posterior C1-C2 fusion
. Transoral odontoid resection

Correct Answer & Explanation

. Halo vest immobilization

Explanation

This is a Type II Hangman's fracture (characterized by significant angulation >11 degrees or translation >3 mm due to disruption of the C2-C3 disc and posterior longitudinal ligament). The recommended treatment is closed reduction and application of a Halo vest. Type I fractures (minimal displacement) are treated with a rigid collar. Type III fractures (associated with bilateral C2-C3 facet dislocations) require open reduction and surgical stabilization.

Question 3403

Topic: 6. Spine

A 45-year-old male presents with severe right lower extremity radiculopathy. Examination reveals notable weakness in ankle dorsiflexion and decreased pinprick sensation over the dorsal aspect of the first web space of the foot. The patellar and Achilles reflexes are normal. A paracentral disc herniation at which intervertebral level is most likely responsible?

. L3-L4
. L4-L5
. L5-S1
. L2-L3
. S1-S2

Correct Answer & Explanation

. L4-L5

Explanation

The clinical findings describe an L5 radiculopathy (extensor hallucis longus weakness and numbness in the first dorsal web space). In the lumbar spine, a typical paracentral disc herniation impinges the traversing nerve root. Therefore, a paracentral herniation at the L4-L5 disc space compresses the descending L5 nerve root.

Question 3404

Topic: Cervical Spine

An 82-year-old man presents with neck pain following a ground-level fall. Imaging reveals a Type II odontoid fracture with 3 mm of posterior displacement. He is neurologically intact but suffers from severe osteoporosis and frailty. What is the most appropriate management?

. Halo vest immobilization for 12 weeks
. Hard cervical collar for 6 to 12 weeks
. Anterior odontoid screw fixation
. Posterior C1-C2 transarticular screw fixation
. Cervical traction followed by Minerva cast

Correct Answer & Explanation

. Hard cervical collar for 6 to 12 weeks

Explanation

In frail elderly patients (>80 years) with Type II odontoid fractures, both surgery and halo vest immobilization carry very high morbidity and mortality rates. The current standard of care for these patients often leans toward a hard cervical collar, accepting a stable fibrous nonunion, which is typically asymptomatic and allows for early mobilization with significantly fewer complications.

Question 3405

Topic: Thoracolumbar Spine & Deformity
According to the Wiltse classification of spondylolisthesis, which subtype is characterized by an elongation or attenuation of the pars interarticularis without a frank bony defect or acute fracture?
. Dysplastic (Type I)
. Isthmic (Type IIa)
. Isthmic (Type IIb)
. Degenerative (Type III)
. Traumatic (Type IV)

Correct Answer & Explanation

. Isthmic (Type IIb)

Explanation

The Wiltse classification categorizes spondylolisthesis by etiology. Type II is isthmic (involving the pars interarticularis). Type IIa involves a pars fatigue fracture (lytic). Type IIb involves an elongated, attenuated pars without a complete separation, believed to result from repeated microfractures that heal in an elongated state. Type IIc is an acute traumatic pars fracture.

Question 3406

Topic: 6. Spine
According to the Denis classification of sacral fractures, which zone has the highest incidence of associated neurological injury (e.g., cauda equina syndrome, bowel/bladder dysfunction)?
. Zone I (Alar zone)
. Zone II (Foraminal zone)
. Zone III (Central canal zone)
. Denis Type A
. Denis Type B

Correct Answer & Explanation

. Zone III (Central canal zone)

Explanation

The Denis classification divides sacral fractures into three zones. Zone I (alar) involves the sacral ala lateral to the foramina. Zone II (foraminal) involves the neural foramina and is often associated with isolated nerve root injuries (e.g., L5, S1). Zone III (central) involves the sacral spinal canal and has the highest rate of severe neurologic injury (>50%), including saddle anesthesia and bowel/bladder incontinence.

Question 3407

Topic: 6. Spine

A 25-year-old male is brought to the trauma bay after a motorcycle accident with a severe C5 burst fracture and profound quadriplegia. His blood pressure is 80/50 mmHg and his heart rate is 48 beats per minute. His extremities are warm and pink. What is the primary pathophysiologic mechanism responsible for his hemodynamic state?

. Hemorrhagic hypovolemia causing decreased venous return
. Loss of sympathetic vascular tone leading to vasodilation
. Direct contusion of the myocardium and intrinsic conducting system
. Vagal nerve sectioning leading to parasympathetic uninhibited overdrive
. Systemic inflammatory response syndrome (SIRS) causing capillary leak

Correct Answer & Explanation

. Loss of sympathetic vascular tone leading to vasodilation

Explanation

The patient is in neurogenic shock, typical of severe cervical or high thoracic spinal cord injuries. The mechanism is a loss of sympathetic descending tone, which leads to unopposed parasympathetic tone (vagal nerve remains intact). This results in profound peripheral vasodilation (hypotension with warm extremities) and an inability to mount a tachycardic response (bradycardia).

Question 3408

Topic: 6. Spine

A 35-year-old male falls from a height and sustains a U-shaped sacral fracture with spinopelvic dissociation. On examination, he has bilateral lower extremity weakness and perianal numbness. Which of the following is the most appropriate surgical stabilization technique to restore spinopelvic continuity?

. Iliosacral screws alone
. Lumbopelvic fixation
. Anterior pelvic external fixator
. Symphyseal plating
. Sacral laminectomy without fusion

Correct Answer & Explanation

. Lumbopelvic fixation

Explanation

Spinopelvic dissociation (such as a U-shaped sacral fracture) disconnects the axial spine from the pelvis. Lumbopelvic fixation (triangular osteosynthesis) bridging the lower lumbar spine to the ilium is biomechanically necessary to restore the weight-bearing axis and allow early mobilization, especially when combined with decompression for neurologic deficits. Iliosacral screws alone are insufficient to resist the shear forces in complete spinopelvic dissociation.

Question 3409

Topic: 6. Spine

A 65-year-old male presents with worsening clumsiness in his hands and difficulty walking. Examination reveals hyperreflexia in both lower extremities, a positive Hoffmann's sign bilaterally, and intrinsic hand muscle wasting. What does the presence of a positive 'finger escape sign' (Wartenberg's sign of the hand) in this patient specifically indicate?

. Ulnar nerve entrapment at the cubital tunnel
. C8-T1 radiculopathy
. Weakness of the palmar interossei due to cervical myelopathy
. Weakness of the extensor digiti minimi
. Loss of proprioception in the little finger

Correct Answer & Explanation

. Weakness of the palmar interossei due to cervical myelopathy

Explanation

The 'finger escape sign' is the inability to hold the ulnar digits in extension and adduction. In the setting of cervical spondylotic myelopathy (CSM), it is caused by central weakness of the intrinsic hand muscles (specifically the palmar interossei) and hypertonicity of the extensor muscles. It is a classic upper motor neuron finding in CSM.

Question 3410

Topic: Cervical Spine

A 75-year-old male is evaluated after a low-energy fall. Cervical spine CT reveals a displaced Type II odontoid fracture. He has no neurologic deficits. His past medical history is significant for severe COPD and osteoporosis. Which of the following is the most appropriate definitive management?

. Halo vest immobilization for 12 weeks
. Rigid cervical collar for 6 weeks
. Anterior odontoid screw fixation
. Posterior C1-C2 instrumental fusion
. Non-rigid soft collar for comfort

Correct Answer & Explanation

. Posterior C1-C2 instrumental fusion

Explanation

Type II odontoid fractures in the elderly have an unacceptably high rate of nonunion. Halo vest immobilization is poorly tolerated and carries high morbidity/mortality, especially with severe COPD. Anterior odontoid screw fixation requires good bone quality and is often contraindicated in severe osteoporosis. Posterior C1-C2 fusion provides the highest union rates and immediate stability, making it the preferred surgical choice for elderly patients.

Question 3411

Topic: 6. Spine

A 60-year-old man presents with progressive hand clumsiness and gait imbalance. Neurological examination reveals an inverted brachioradialis reflex. What is the neuroanatomic significance of this specific physical finding?

. An upper motor neuron lesion at the C4 level
. A lower motor neuron lesion at C7 with upper motor neuron signs below
. A lower motor neuron lesion at C5/C6 with an upper motor neuron lesion below this level
. A pure lower motor neuron lesion of the C8 nerve root
. A complete spinal cord transection at T1

Correct Answer & Explanation

. A lower motor neuron lesion at C5/C6 with an upper motor neuron lesion below this level

Explanation

An inverted brachioradialis reflex occurs when tapping the brachioradialis tendon (C5-C6) produces finger flexion (C8) rather than elbow flexion/supination. This finding indicates a lower motor neuron lesion at the level of the reflex (C5/C6, causing loss of the normal reflex) combined with an upper motor neuron lesion below that level (hyperreflexia of the C8 finger flexors), classic for cervical spondylotic myelopathy at C5-C6.

Question 3412

Topic: Thoracolumbar Spine & Deformity
A 14-year-old gymnast presents with lower back pain exacerbated by extension. Lateral lumbar radiographs show a pars interarticularis defect at L5 with a 30% anterior translation of L5 on S1. According to the Meyerding classification, what grade of spondylolisthesis does this patient have?
. Grade I
. Grade II
. Grade III
. Grade IV
. Grade V

Correct Answer & Explanation

. Grade II

Explanation

The Meyerding classification grades the severity of spondylolisthesis based on the percentage of anterior translation of the superior vertebral body over the inferior one. Grade I is 0-25%, Grade II is 26-50%, Grade III is 51-75%, Grade IV is 76-100%, and Grade V (spondyloptosis) is >100%. A 30% slip falls into Grade II.

Question 3413

Topic: 6. Spine

A 60-year-old male presents with clumsy hands and a broad-based gait. Examination reveals an inverted brachioradialis reflex. This clinical finding most specifically localizes the compressive pathology to which cervical spinal level?

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

Correct Answer & Explanation

. C5-C6

Explanation

An inverted brachioradialis reflex (striking the brachioradialis tendon produces finger flexion rather than elbow flexion/supination) indicates a lower motor neuron lesion at C5 or C6 (absent normal reflex) and an upper motor neuron lesion below that level (hyperactive finger flexors, C8). It specifically localizes spinal cord compression to the C5-C6 level.

Question 3414

Topic: Thoracolumbar Spine & Deformity
In the Wiltse classification of spondylolisthesis, a slip secondary to an elongated but intact pars interarticularis is classified as:
. Type I (Dysplastic)
. Type IIA (Lytic)
. Type IIB (Elongated)
. Type III (Degenerative)
. Type IV (Traumatic)

Correct Answer & Explanation

. Type IIA (Lytic)

Explanation

The Wiltse classification defines Type II as Isthmic. It is subdivided into IIA (lytic fatigue fracture of the pars), IIB (elongated but intact pars, due to repeated healed microfractures), and IIC (acute pars fracture). Type I is dysplastic, Type III is degenerative, and Type IV is traumatic (fracture other than pars).

Question 3415

Topic: 6. Spine

A 65-year-old male presents with clumsy hands, difficulty buttoning his shirt, and a broad-based gait. Physical examination reveals a positive inverted brachioradialis reflex and positive Hoffmann's sign. Which spinal cord tract is primarily responsible for the myelopathic spasticity and hyperreflexia seen in this patient?

. Spinothalamic tract
. Dorsal columns
. Lateral corticospinal tract
. Rubrospinal tract
. Vestibulospinal tract

Correct Answer & Explanation

. Lateral corticospinal tract

Explanation

The patient has signs of Cervical Spondylotic Myelopathy (CSM). The lateral corticospinal tract carries descending upper motor neuron signals; its compression leads to spasticity, hyperreflexia, weakness, and positive pathological reflexes (Hoffmann, Babinski). The dorsal columns relate to proprioception and vibration, while the spinothalamic tracts carry pain and temperature.

Question 3416

Topic: 6. Spine
A 14-year-old female gymnast presents with persistent low back pain and radicular symptoms in her L5 distribution. Radiographs demonstrate a Grade III isthmic spondylolisthesis at L5-S1. What is the primary anatomic pathomechanism leading to her L5 radiculopathy?
. Compression of the L5 nerve root in the lateral recess by a herniated disc.
. Tension and stretch of the L5 nerve root over the prominent sacral dome.
. Compression of the L5 nerve root by the fibrocartilaginous pseudoarthrosis mass at the pars interarticularis.
. Hypertrophy of the ligamentum flavum causing central canal stenosis.
. Traction on the S1 nerve root mimicking L5 radicular symptoms.

Correct Answer & Explanation

. Compression of the L5 nerve root by the fibrocartilaginous pseudoarthrosis mass at the pars interarticularis.

Explanation

In isthmic spondylolisthesis, L5 radiculopathy is most commonly caused by compression of the exiting L5 nerve root in the neural foramen by the fibrocartilaginous mass (Gill body) that forms at the site of the pars interarticularis defect (spondylolysis), as well as by foraminal narrowing from the anterior translation of L5 on S1.

Question 3417

Topic: 6. Spine
According to the Levine-Edwards classification, a Type II Hangman's fracture (traumatic spondylolisthesis of the axis) features a fracture of the pars interarticularis with significant translation and angulation. What is the primary mechanism of injury responsible for a Type II fracture?
. Hyperextension and axial loading
. Hyperextension and rebound flexion
. Hyperflexion and axial loading
. Hyperflexion and distraction
. Lateral bending and rotation

Correct Answer & Explanation

. Hyperextension and rebound flexion

Explanation

A Levine-Edwards Type II Hangman's fracture occurs via initial hyperextension followed by significant rebound flexion and axial loading. This mechanism leads to disruption of the C2-C3 intervertebral disc and posterior longitudinal ligament, causing translation and angulation. Type I is caused by hyperextension/axial load; Type IIA by flexion/distraction; and Type III by flexion/compression.

Question 3418

Topic: 6. Spine

In the evaluation of a patient with cervical spondylotic myelopathy, the Nurick grading system is frequently utilized to assess severity. Which of the following clinical descriptions best corresponds to a Nurick Grade 3 patient?

. Signs of root involvement only, normal gait
. Mild gait involvement, able to be employed
. Gait abnormality prevents employment, but ambulates without assistance
. Ambulates only with assistance (cane or walker)
. Chair-bound or bedridden

Correct Answer & Explanation

. Gait abnormality prevents employment, but ambulates without assistance

Explanation

The Nurick classification evaluates cervical myelopathy based primarily on ambulation and employment status. Grade 0: Root signs only. Grade 1: Cord signs but normal gait. Grade 2: Mild gait involvement, able to work. Grade 3: Gait abnormality prevents employment, but the patient can walk unassisted. Grade 4: Ambulates only with assistance. Grade 5: Chair-bound or bedridden.

Question 3419

Topic: Cervical Spine

According to the Grauer modification of the Anderson and D'Alonzo classification for odontoid fractures, a Type IIB fracture is best described as:

. An undisplaced transverse fracture through the waist of the odontoid
. A fracture extending from the anterior-inferior base to the posterior-superior tip
. A fracture extending from the anterior-superior tip to the posterior-inferior base
. A highly comminuted fracture through the base of the odontoid
. An avulsion fracture of the tip of the odontoid process

Correct Answer & Explanation

. A fracture extending from the anterior-inferior base to the posterior-superior tip

Explanation

The Grauer modification helps dictate treatment for Type II odontoid fractures. Type IIA is undisplaced/minimally displaced (<1mm) and treated externally. Type IIB features a displaced transverse fracture or an oblique fracture from anterior-superior to posterior-inferior. This pattern is ideal for an anterior odontoid screw because the fracture line is perpendicular to the screw trajectory, allowing for compression. Type IIC is an anterior-inferior to posterior-superior oblique fracture (or comminuted base), which parallels the screw trajectory, risks shearing, and thus requires posterior C1-C2 fusion.

Question 3420

Topic: 6. Spine

A 65-year-old man presents with bilateral leg claudication. He is subjected to a stationary bicycle test to differentiate neurogenic claudication (lumbar spinal stenosis) from vascular claudication. Which outcome is most indicative of neurogenic claudication?

. Pain is rapidly exacerbated when cycling in an upright posture but relieved when walking
. Pain is exacerbated when cycling in a flexed forward posture compared to upright
. Pain is delayed or relieved when cycling in a flexed forward posture compared to walking
. Pain occurs at a constant distance regardless of spinal posture during cycling
. Ankle-brachial index (ABI) drops significantly immediately after cycling

Correct Answer & Explanation

. Pain is exacerbated when cycling in a flexed forward posture compared to upright

Explanation

The bicycle test helps differentiate neurogenic from vascular claudication. Patients with neurogenic claudication typically experience symptom relief when the lumbar spine is flexed (which increases the anteroposterior diameter of the spinal canal and neural foramina). Leaning forward on a bicycle promotes spinal flexion, allowing them to cycle much further without pain than they can walk upright. Vascular claudication is strictly demand-dependent and will cause pain during cycling regardless of posture (Option D).

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