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6. Spine MCQs

Practice Set 344 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 6861

Topic: 6. Spine
A 65-year-old male presents with classic neurogenic claudication. On MRI, which of the following findings is most consistently associated with symptomatic central lumbar spinal stenosis?
. Modic Type 1 endplate changes
. A high-intensity zone (HIZ) in the posterior annulus
. Decreased cross-sectional area of the dural sac to less than 100 mm²
. Presence of Schmorl's nodes
. Unilateral pars interarticularis defect

Correct Answer & Explanation

. Decreased cross-sectional area of the dural sac to less than 100 mm²

Explanation

A dural sac cross-sectional area of less than 100 mm² is radiographically diagnostic for central lumbar spinal stenosis and correlates highly with the clinical presentation of neurogenic claudication. An area of less than 75 mm² typically indicates severe stenosis.

Question 6862

Topic: 6. Spine

A 42-year-old female presents with severe lower back pain, bilateral sciatica, and new-onset urinary incontinence. An MRI demonstrates a massive L4-L5 central disc herniation. Pathophysiologically, what is the initial mechanism of neurological damage in cauda equina syndrome?

. Direct mechanical severing of the nerve rootlets
. Venous congestion leading to localized nerve root ischemia
. Arterial vasospasm of the artery of Adamkiewicz
. Demyelination triggered by inflammatory cytokines
. Cerebrospinal fluid leak causing dural tension

Correct Answer & Explanation

. Venous congestion leading to localized nerve root ischemia

Explanation

The initial pathophysiology of cauda equina syndrome involves mechanical compression that obstructs venous outflow. This leads to profound venous congestion, interstitial edema, and subsequent ischemia of the delicate nerve rootlets.

Question 6863

Topic: 6. Spine

A 25-year-old male sustains a cervical spine injury resulting in C5 ASIA A tetraplegia. On presentation, he is profoundly hypotensive and bradycardic. Which pathophysiological mechanism is primarily responsible for his hemodynamic instability?

. Loss of parasympathetic outflow
. Hypovolemia from internal hemorrhage
. Loss of sympathetic vascular tone
. Autonomic dysreflexia
. Massive release of inflammatory cytokines

Correct Answer & Explanation

. Loss of sympathetic vascular tone

Explanation

Neurogenic shock is characterized by hypotension and bradycardia due to the disruption of descending sympathetic pathways in the cervical or high thoracic spine. This leads to unopposed vagal tone and loss of peripheral vascular resistance.

Question 6864

Topic: Cervical Spine

A 55-year-old female with long-standing rheumatoid arthritis requires intubation. Flexion-extension cervical radiographs are obtained. Which measurement is the most reliable radiographic indicator of potential neurological compromise due to atlantoaxial subluxation?

. Anterior atlantodental interval (ADI) > 3 mm
. Posterior atlantodental interval (PADI) < 14 mm
. Basion-dental interval > 12 mm
. Powers ratio > 1.0
. C2-C7 sagittal Cobb angle < 10 degrees

Correct Answer & Explanation

. Posterior atlantodental interval (PADI) < 14 mm

Explanation

The Posterior Atlantodental Interval (PADI), also known as the Space Available for the Cord (SAC), is the most reliable predictor of neurologic deficit in RA. A PADI of less than 14 mm strongly correlates with a high risk of spinal cord compression.

Question 6865

Topic: 6. Spine

In the pathogenesis of cervical spondylotic myelopathy, anterior cord compression leads to ischemia primarily due to the mechanical obstruction of which of the following vascular structures?

. Posterior spinal artery
. Anterior spinal artery
. Vertebral artery
. Radicular artery
. Sulcal artery

Correct Answer & Explanation

. Anterior spinal artery

Explanation

Cervical spondylotic myelopathy causes direct mechanical compression of the spinal cord and secondary ischemic changes due to compression of the anterior spinal artery. This primarily affects the anterior horn cells and the corticospinal tracts.

Question 6866

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male sustains an L1 burst fracture. He is neurologically intact. MRI reveals an indeterminate status of the posterior ligamentous complex (PLC). Using the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the patient's calculated score, and what is the corresponding treatment recommendation?

. Score 2: Non-operative management
. Score 3: Non-operative management
. Score 4: Surgeon's preference (operative or non-operative)
. Score 5: Operative management
. Score 6: Operative management

Correct Answer & Explanation

. Score 4: Surgeon's preference (operative or non-operative)

Explanation

The TLICS score is calculated as follows: Morphology - Burst fracture = 2 points; Neurological status - Intact = 0 points; PLC status - Indeterminate = 2 points. Total = 4 points. A TLICS score of less than 4 recommends non-operative treatment, greater than 4 recommends operative treatment, and exactly 4 represents an equivocal case where either operative or non-operative management is acceptable based on surgeon preference.

Question 6867

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female gymnast presents with progressive low back pain. Radiographs show a Grade 2 L5-S1 spondylolisthesis. MRI demonstrates an intact pars interarticularis but elongated pars and pedicles. According to the Wiltse classification, what type of spondylolisthesis does she have?
. Type I (Dysplastic)
. Type II (Isthmic)
. Type III (Degenerative)
. Type IV (Traumatic)
. Type V (Pathologic)

Correct Answer & Explanation

. Type I (Dysplastic)

Explanation

Wiltse Type I (Dysplastic) spondylolisthesis is due to congenital abnormalities of the upper sacrum or L5 arch leading to facet incompetence. The pars is often elongated but remains intact. Type II (Isthmic) involves a lytic defect or stress fracture of the pars interarticularis, which is more common in gymnasts, but the MRI specifically noted an intact pars in this scenario.

Question 6868

Topic: 6. Spine

A 45-year-old male presents with right-sided neck pain radiating down his arm, accompanied by weakness in triceps extension and wrist flexion, as well as numbness in his middle finger. The triceps reflex is absent. Which cervical nerve root is most likely compressed?

. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C7

Explanation

C7 radiculopathy is the most common cervical radiculopathy. Its classic clinical presentation includes pain/numbness radiating to the middle finger, weakness in elbow extension (triceps) and wrist flexion (flexor carpi radialis), and a diminished or absent triceps reflex. C6 typically affects the biceps reflex, wrist extension, and numbness in the thumb/index finger.

Question 6869

Topic: 6. Spine

A 22-year-old unrestrained driver is involved in a motor vehicle collision. Cervical spine imaging reveals a traumatic spondylolisthesis of the axis (Hangman's fracture) with severe angulation and minimal translation. The fracture line is oblique from anterior-inferior to posterior-superior. According to the Levine-Edwards classification (Type IIA), what is the most appropriate initial management, and what is its pathomechanism?

. Immediate cervical traction; mechanism is hyperextension and axial loading
. Immediate cervical traction; mechanism is flexion and distraction
. Application of a halo vest in slight compression; mechanism is flexion and distraction
. Application of a hard cervical collar; mechanism is hyperextension and axial loading
. Odontoid screw fixation; mechanism is lateral mass compression

Correct Answer & Explanation

. Application of a halo vest in slight compression; mechanism is flexion and distraction

Explanation

A Levine-Edwards Type IIA Hangman's fracture features significant angulation with minimal translation and an oblique fracture line. The mechanism of injury is flexion and distraction. Traction is strictly contraindicated as it will exacerbate the translation and widen the disc space. The correct initial management involves gentle reduction with extension and compression, often maintained in a halo vest.

Question 6870

Topic: Cervical Spine

An 82-year-old female presents with a Type II odontoid fracture following a ground-level fall. She has multiple comorbidities but is neurologically intact. What is the preferred definitive treatment for this patient to minimize mortality and optimize union rates?

. Application of a halo vest for 12 weeks
. Hard cervical collar immobilization for 6 weeks
. Posterior C1-C2 fusion
. Anterior odontoid screw fixation
. Occipitocervical fusion

Correct Answer & Explanation

. Posterior C1-C2 fusion

Explanation

Type II odontoid fractures in the elderly (>70-80 years old) are notoriously difficult to treat. Conservative management with a halo vest is associated with unacceptably high morbidity and mortality in the elderly population (up to 40%). Anterior odontoid screws have high failure rates due to osteopenia. Posterior C1-C2 arthrodesis is the most reliable treatment, offering the highest union rates and lower mortality compared to halo placement in this specific demographic.

Question 6871

Topic: 6. Spine

A 65-year-old man complains of bilateral calf pain that occurs after walking two blocks. The pain is relieved when he leans forward on a shopping cart or sits down. He states he can ride a stationary bicycle for 30 minutes without symptoms. These clinical findings are most characteristic of:

. Vascular claudication
. Lumbar disc herniation at L4-L5
. Neurogenic claudication secondary to spinal stenosis
. Diabetic peripheral neuropathy
. Cervical myelopathy

Correct Answer & Explanation

. Neurogenic claudication secondary to spinal stenosis

Explanation

This is a classic presentation of neurogenic claudication caused by lumbar spinal stenosis. Symptoms are typically exacerbated by extension (walking upright) which narrows the spinal canal, and relieved by flexion (leaning on a cart, sitting, cycling) which widens the canal and neural foramina. Vascular claudication would typically cause pain during cycling as well due to muscular oxygen demand.

Question 6872

Topic: Cervical Spine

A 62-year-old female with long-standing rheumatoid arthritis presents with neck pain and mild upper extremity clumsiness. Lateral flexion-extension radiographs of the cervical spine demonstrate atlantoaxial subluxation (AAS). Which of the following radiographic measurements is widely considered an absolute indication for surgical stabilization?

. Anterior atlantodental interval (ADI) of > 3 mm
. Posterior atlantodental interval (PADI) < 14 mm
. Anterior atlantodental interval (ADI) of > 5 mm
. Posterior atlantodental interval (PADI) > 18 mm
. C2-C3 subluxation of 2 mm

Correct Answer & Explanation

. Posterior atlantodental interval (PADI) < 14 mm

Explanation

In rheumatoid arthritis, the posterior atlantodental interval (PADI), also known as the space available for the cord (SAC), is the most reliable predictor of neurologic compromise and recovery. A PADI of less than 14 mm indicates critical spinal canal narrowing and is a strong indication for surgical stabilization, even if neurological symptoms are mild.

Question 6873

Topic: Cervical Spine

In a patient with severe rheumatoid arthritis, which of the following cervical spine radiographic measurements is the most reliable predictor of impending neurologic deficit?

. Anterior atlanto-dens interval (ADI) greater than 3.5 mm
. Powers ratio greater than 1.0
. McGregor's line violation by the odontoid
. Posterior atlanto-dens interval (PADI) less than 14 mm
. Ranawat line measurement of 15 mm

Correct Answer & Explanation

. Posterior atlanto-dens interval (PADI) less than 14 mm

Explanation

The posterior atlanto-dens interval (PADI), also known as the space available for the cord (SAC), is the most reliable predictor of neurologic paralysis in rheumatoid atlantoaxial subluxation. A PADI of less than 14 mm strongly correlates with neurologic compromise.

Question 6874

Topic: 6. Spine

A 65-year-old male presents with deteriorating handwriting, frequent falls, and hyperreflexia in the bilateral lower extremities. MRI of the cervical spine shows severe stenosis at C5-C6. Which of the following physical exam findings is most specific for cervical myelopathy at this level?

. Positive Spurling's test
. Hoffmann's sign
. Lhermitte's sign
. Positive Babinski reflex
. Inverted radial reflex

Correct Answer & Explanation

. Inverted radial reflex

Explanation

The inverted radial reflex (or inverted supinator reflex) is highly specific for cervical myelopathy localized to the C5-C6 level. It is elicited by tapping the brachioradialis tendon, resulting in paradoxical finger flexion. Hoffmann's sign is sensitive for upper motor neuron lesions but less specific.

Question 6875

Topic: Thoracolumbar Spine & Deformity

According to the Thoracolumbar Injury Classification and Severity Score (TLICS), which of the following morphologic injury patterns is assigned the highest point value?

. Compression fracture
. Burst fracture
. Translation/rotation injury
. Distraction injury
. Wedge fracture

Correct Answer & Explanation

. Distraction injury

Explanation

In the TLICS system for thoracolumbar trauma, points for morphology are assigned as follows: Compression fracture = 1 point; Burst fracture = 2 points; Translation/rotation = 3 points; Distraction = 4 points. Thus, distraction injuries are deemed the most unstable morphology.

Question 6876

Topic: Cervical Spine

A 65-year-old male presents with deteriorating handwriting, frequent tripping, and hyperreflexia in all extremities. The Hoffmann sign is positive bilaterally. Which surgical approach is most appropriate for a patient with 4-level cervical spondylotic myelopathy, neutral sagittal alignment, and no significant neck pain?

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

Correct Answer & Explanation

. Posterior cervical laminoplasty

Explanation

Posterior cervical laminoplasty is ideal for multi-level cervical spondylotic myelopathy in the setting of neutral or lordotic sagittal alignment with minimal axial neck pain. It preserves motion and avoids the morbidity of multi-level anterior surgery or posterior fusion.

Question 6877

Topic: 6. Spine
A 24-year-old male is involved in a motor vehicle accident and sustains a traumatic spondylolisthesis of the axis (Hangman's fracture). Imaging shows a fracture through the pars interarticularis with severe angular kyphosis but minimal translation. Traction exacerbates the deformity. What is the appropriate classification and treatment?
. Levine-Edwards Type I; hard cervical collar
. Levine-Edwards Type II; halo-vest immobilization with initial traction
. Levine-Edwards Type IIA; halo-vest immobilization in extension without traction
. Levine-Edwards Type III; anterior cervical discectomy and fusion
. Levine-Edwards Type III; posterior C1-C3 fusion

Correct Answer & Explanation

. Levine-Edwards Type IIA; halo-vest immobilization in extension without traction

Explanation

Type IIA Hangman's fractures feature severe angulation with minimal translation. Traction is strictly contraindicated as it exacerbates the deformity; treatment requires gentle reduction in extension and compression followed by halo vest immobilization.

Question 6878

Topic: Thoracolumbar Spine & Deformity

A 14-year-old male presents for evaluation of scoliosis. He is tall and thin with a wingspan greater than his height, and hypermobile joints. A mutation in the FBN1 gene is suspected. Which associated ocular abnormality is most characteristic of this condition?

. Inferior lens dislocation
. Superior lens dislocation
. Blue sclera
. Retinitis pigmentosa
. Cataracts

Correct Answer & Explanation

. Superior lens dislocation

Explanation

The patient has Marfan syndrome, caused by an autosomal dominant mutation in the FBN1 gene (fibrillin-1). A classic ocular finding in Marfan syndrome is superior (upward) lens dislocation (ectopia lentis). By contrast, homocystinuria, which can present with a similar habitus, is typically associated with inferior (downward) lens dislocation.

Question 6879

Topic: Thoracolumbar Spine & Deformity

A 10-year-old boy with cerebral palsy presents with a rapidly progressive thoracolumbar scoliosis measuring 80 degrees, causing significant trunk imbalance and difficulty with seating. He has a history of non-ambulatory status and recurrent respiratory infections. Which of the following is the primary indication for surgical intervention in this patient, beyond cosmetic concerns?

. Prevention of progression during adolescent growth spurt.
. Improvement of pulmonary function and prevention of restrictive lung disease.
. Management of intractable back pain.
. Restoration of ambulatory function.
. Correction of pelvic obliquity to improve sitting balance and prevent pressure sores.

Correct Answer & Explanation

. Correction of pelvic obliquity to improve sitting balance and prevent pressure sores.

Explanation

For non-ambulatory patients with neuromuscular scoliosis, the primary indication for surgical intervention is often to improve sitting balance, correct pelvic obliquity, and prevent pressure sores, thereby enhancing quality of life and facilitating care. While severe curves can lead to pulmonary compromise, surgical correction in non-ambulatory patients typically results in only modest improvements in pulmonary function, and preventing restrictive lung disease is a secondary goal compared to seating balance. Pain is less common in this population compared to idiopathic scoliosis. Restoration of ambulatory function is not an indication for surgery in a non-ambulatory patient. Preventing progression is a general indication, but for curves this severe, functional improvement takes precedence.

Question 6880

Topic: 6. Spine

A 55-year-old male presents with acute onset bilateral leg weakness, urinary retention, and saddle anesthesia following a lumbar discectomy performed 2 days prior. His symptoms are rapidly worsening. On examination, he has diminished rectal tone and absent ankle reflexes bilaterally. What is the most crucial diagnostic step to undertake immediately?

. Immediate lumbar MRI with gadolinium.
. Electromyography and nerve conduction studies.
. High-dose intravenous corticosteroids.
. Urgent surgical exploration of the lumbar spine.
. Consultation with a neurosurgeon for conservative management options.

Correct Answer & Explanation

. Urgent surgical exploration of the lumbar spine.

Explanation

The patient's symptoms (bilateral leg weakness, urinary retention, saddle anesthesia, diminished rectal tone, absent ankle reflexes) are classic for cauda equina syndrome (CES). Given the recent lumbar discectomy and rapidly worsening symptoms, the most crucial and immediate step is urgent surgical exploration of the lumbar spine. This is to decompress the neural elements, likely due to a retained disc fragment, epidural hematoma, or seroma. While an MRI would confirm the diagnosis and identify the precise compressive lesion, in a rapidly progressive post-operative CES, surgical exploration should not be delayed by imaging if the clinical suspicion is high and the patient is unstable. Electromyography is not for acute diagnosis. Corticosteroids are not indicated and delay definitive treatment. Conservative management is contraindicated in acute CES.

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