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6. Spine MCQs

Practice Set 305 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 6081

Topic: 6. Spine

A 9-month-old male is evaluated for a left thoracic spinal curve of 25 degrees. The rib-vertebra angle difference (RVAD) of Mehta is measured at 28 degrees. Phase 2 rib-head overlap is noted on the apical vertebra. What is the most likely natural history and appropriate treatment for this deformity?

. High likelihood of spontaneous resolution; observe
. High likelihood of progression; serial Mehta casting
. High likelihood of progression; immediate posterior spinal fusion
. Moderate likelihood of progression; prescribe a Milwaukee brace
. Likelihood of progression cannot be determined; observe for 6 months

Correct Answer & Explanation

. High likelihood of spontaneous resolution; observe

Explanation

Infantile idiopathic scoliosis occurs in children <3 years old, most commonly in males with left-sided thoracic curves. The Mehta Rib-Vertebra Angle Difference (RVAD) predicts progression: an RVAD >20 degrees, especially with Phase 2 rib-head overlap, indicates a progressive curve. The gold standard early treatment for progressive infantile idiopathic scoliosis is elongation-derotation-flexion casting (Mehta casting), which harnesses infantile growth to correct the deformity.

Question 6082

Topic: 6. Spine

A 2-year-old girl is noted to have a spinal deformity. Radiographs

show a fully segmented hemivertebra at T8 causing a 35-degree scoliotic curve. Prior to surgical intervention, which of the following screening studies are mandatory to evaluate for the most commonly associated anomalies?

. Echocardiogram and brain MRI
. Renal ultrasound and whole-spine MRI
. Renal ultrasound and pulmonary function tests
. Echocardiogram and chromosomal microarray
. Pelvic ultrasound and lower extremity radiographs

Correct Answer & Explanation

. Echocardiogram and brain MRI

Explanation

Congenital scoliosis, resulting from failures of formation (e.g., hemivertebra) or segmentation, has a high association with other organ system anomalies occurring during the same embryonic period. Genitourinary anomalies (e.g., renal agenesis) occur in 20-30% of patients, requiring a screening renal ultrasound. Intraspinal anomalies (e.g., tethered cord, syringomyelia, diastematomyelia) occur in up to 40%, necessitating an MRI of the entire neural axis. Cardiac anomalies are also common, making echocardiogram a standard part of the workup, but the strict combination of renal US and spine MRI is absolute board-tested standard.

Question 6083

Topic: 6. Spine

A pediatric patient presents with a congenital spinal deformity.

Which of the following specific vertebral anomalies carries the highest risk of rapid curve progression and often requires early surgical intervention?

. A single block vertebra
. A wedge vertebra
. An unsegmented hemivertebra
. A fully segmented hemivertebra with a contralateral unsegmented bar
. A butterfly vertebra

Correct Answer & Explanation

. A single block vertebra

Explanation

The highest risk for rapid curve progression in congenital scoliosis is seen with a fully segmented hemivertebra accompanied by a contralateral unsegmented bar. This creates unbalanced, asymmetric growth (growth potential on one side without corresponding growth on the contralateral tethered side). This combination progresses at a rate of 5 to 10 degrees per year and requires early surgical fusion to halt progression.

Question 6084

Topic: 6. Spine
A 5-year-old girl is evaluated for a high-riding, hypoplastic left scapula. Imaging reveals a bony bridge between the cervical spine and the superior angle of the scapula (an omovertebral bone). This deformity is most frequently associated with which of the following?
. Trisomy 21
. Klippel-Feil syndrome
. VACTERL association
. Neurofibromatosis Type 1
. Marfan syndrome

Correct Answer & Explanation

. Klippel-Feil syndrome

Explanation

The patient has Sprengel deformity, an arrest of the normal embryologic descent of the scapula. About 30% of cases feature an omovertebral bone. It is strongly associated with Klippel-Feil syndrome (congenital fusion of cervical vertebrae) as well as congenital scoliosis and diastematomyelia. Careful screening of the cervical spine and renal system is mandated.

Question 6085

Topic: 6. Spine

A 6-year-old girl with Morquio syndrome (Mucopolysaccharidosis Type IV) is scheduled for orthopedic evaluation. Before planning any surgical procedures, which of the following conditions poses the most immediate, life-threatening risk to this patient?

. Severe thoracolumbar kyphoscoliosis
. Progressive genu valgum
. Atlantoaxial instability due to odontoid hypoplasia
. Rapidly progressive hip dysplasia
. Early-onset osteoarthritis of the knees

Correct Answer & Explanation

. Severe thoracolumbar kyphoscoliosis

Explanation

Morquio syndrome (MPS IV) is caused by a deficiency in N-acetylgalactosamine-6-sulfatase or beta-galactosidase. A hallmark skeletal feature is severe odontoid hypoplasia and ligamentous laxity, which leads to life-threatening atlantoaxial instability and cervical myelopathy. Flexion-extension cervical spine radiographs are mandatory to rule out instability before administering general anesthesia to avoid catastrophic spinal cord injury.

Question 6086

Topic: Thoracolumbar Spine & Deformity
A 15-year-old female gymnast presents with persistent lower back pain. Lateral radiographs of the lumbar spine reveal a pars interarticularis defect at L5 and a forward translation of L5 on S1. The superior endplate of S1 is divided into four equal parts, and the posterior cortex of L5 sits over the second quartile. According to the Meyerding classification, what is the grade of this spondylolisthesis?
. Grade I
. Grade II
. Grade III
. Grade IV
. Spondyloptosis

Correct Answer & Explanation

. Grade II

Explanation

The Meyerding classification grades spondylolisthesis based on the percentage of forward slip 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%; Grade V is >100% (spondyloptosis). A slip in the second quartile (26-50%) is Grade II.

Question 6087

Topic: 6. Spine

An 8-month-old infant with homozygous achondroplasia presents with witnessed episodes of central sleep apnea, hyperreflexia, and generalized hypotonia. What is the most likely anatomic cause of these severe neurological symptoms?

. Thoracolumbar kyphosis
. Atlantoaxial instability
. Foramen magnum stenosis
. Lumbar spinal stenosis
. Craniosynostosis

Correct Answer & Explanation

. Thoracolumbar kyphosis

Explanation

Foramen magnum stenosis is a critical and potentially lethal complication in infants with achondroplasia, caused by defective endochondral ossification of the skull base. It leads to cervicomedullary compression, which presents clinically as central sleep apnea, brisk deep tendon reflexes, hypotonia, and motor delays. Urgent neurosurgical decompression is indicated in symptomatic patients.

Question 6088

Topic: 6. Spine

A newborn is evaluated for congenital scoliosis. Which of the following radiographic vertebral anomalies carries the highest risk for rapid, unrelenting curve progression and typically requires early in situ spinal fusion?

. Single fully segmented hemivertebra
. Unilateral unsegmented bar with a contralateral hemivertebra
. Block vertebra
. Butterfly vertebra
. Incarcerated hemivertebra

Correct Answer & Explanation

. Single fully segmented hemivertebra

Explanation

A unilateral unsegmented bar with a contralateral hemivertebra at the same level provides a severe growth tether on one side and excessive growth potential on the convex side. This combination has nearly a 100% chance of rapid progression and requires early surgical fusion.

Question 6089

Topic: 6. Spine

A 5-year-old boy is brought to the emergency department after a low-speed motor vehicle collision. He is neurologically intact with no neck pain. Lateral cervical spine radiographs show 3 mm of anterior translation of C2 on C3. The Swischuk line passes 1 mm anterior to the anterior aspect of the posterior arch of C3. What is the most appropriate management?

. Application of a halo vest
. Posterior C2-C3 spinal fusion
. Rigid cervical collar for 6 weeks
. Flexion-extension radiographs
. Reassurance and observation

Correct Answer & Explanation

. Application of a halo vest

Explanation

This scenario describes physiologic pseudosubluxation of C2 on C3, which is common in children under 8 years. A Swischuk line passing within 2 mm of the anterior aspect of the posterior arch of C3 confirms this is a normal variant requiring no intervention.

Question 6090

Topic: 6. Spine

A 65-year-old female with long-standing, severe rheumatoid arthritis presents with progressive clumsiness in her hands and difficulty walking. Flexion-extension radiographs of the cervical spine demonstrate atlantoaxial instability. Which of the following radiographic parameters is the most reliable predictor of neurologic recovery following posterior surgical stabilization?

. Anterior atlantodental interval (ADI)
. Posterior atlantodental interval (PADI)
. Degree of basilar invagination
. Overall subaxial cervical lordosis
. Ranawat criterion

Correct Answer & Explanation

. Anterior atlantodental interval (ADI)

Explanation

The Posterior Atlantodental Interval (PADI), also known as the space available for the cord (SAC), is the most reliable predictor of neurologic recovery in rheumatoid patients with atlantoaxial subluxation. A PADI of less than 14 mm is associated with an increased risk of neurologic deficit, and a PADI of less than 10 mm indicates a poor prognosis for neurologic recovery even after surgical decompression and stabilization. The ADI does not directly correlate with the space available for the spinal cord.

Question 6091

Topic: Thoracolumbar Spine & Deformity

In the assessment of spinopelvic parameters for a patient undergoing surgical correction for adult spinal deformity, Pelvic Incidence (PI) is considered a fixed morphological parameter once skeletal maturity is reached. PI is mathematically defined as the algebraic sum of which two parameters?

. Pelvic tilt + Lumbar lordosis
. Pelvic tilt + Sacral slope
. Sacral slope + Lumbar lordosis
. Thoracic kyphosis + Lumbar lordosis
. Sacral slope - Pelvic tilt

Correct Answer & Explanation

. Pelvic tilt + Lumbar lordosis

Explanation

Pelvic Incidence (PI) is a fundamental, fixed morphological parameter of the pelvis, defined as the angle between a line perpendicular to the sacral plate at its midpoint and a line connecting the same point to the center of the bicoxofemoral axis. Geometrically, PI is equal to the sum of Pelvic Tilt (PT) and Sacral Slope (SS). PI = PT + SS.

Question 6092

Topic: 6. Spine

A 45-year-old male presents with severe, burning right leg pain radiating down the anterior thigh to the medial aspect of his lower leg. Motor examination reveals 4/5 strength in knee extension. MRI of the lumbar spine reveals a far lateral (extraforaminal) disc herniation at the L4-L5 level on the right side. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L3

Explanation

In the lumbar spine, a far lateral (extraforaminal) disc herniation compresses the exiting nerve root at the same level, which is the L4 nerve root in an L4-L5 herniation. In contrast, a central or paracentral disc herniation at L4-L5 would compress the traversing L5 nerve root. The patient's clinical presentation (weakness in knee extension, pain radiating to the medial lower leg) is consistent with an L4 radiculopathy.

Question 6093

Topic: 6. Spine
A 72-year-old man with known cervical spondylosis sustains a hyperextension injury to his neck in a low-speed motor vehicle collision. He presents to the emergency department with profound weakness in his bilateral upper extremities, particularly the hands, but retains 4/5 strength in his lower extremities. Perianal sensation and rectal tone are intact. What is the most likely diagnosis?
. Anterior Cord Syndrome
. Posterior Cord Syndrome
. Central Cord Syndrome
. Brown-Séquard Syndrome
. Cauda Equina Syndrome

Correct Answer & Explanation

. Central Cord Syndrome

Explanation

Central Cord Syndrome typically occurs in older individuals with pre-existing cervical spondylosis following a hyperextension injury. It is characterized by motor weakness that is disproportionately greater in the upper extremities (especially distal hands) compared to the lower extremities, along with variable sensory loss and bladder dysfunction. This pattern occurs because the corticospinal tracts for the upper extremities are located more centrally within the spinal cord compared to the peripherally located tracts for the lower extremities.

Question 6094

Topic: Thoracolumbar Spine & Deformity

A 30-year-old construction worker falls from a height of 10 feet, sustaining an L1 burst fracture. Neurological examination is completely normal (intact). MRI demonstrates no disruption of the posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is this patient's total score?

. 0
. 2
. 4
. 5
. 7

Correct Answer & Explanation

. 0

Explanation

The TLICS score is calculated based on three categories: injury morphology, neurological status, and integrity of the PLC. For this patient: Morphology = Burst fracture (2 points); Neurological status = Intact (0 points); PLC = Intact (0 points). Total score = 2. A TLICS score of <= 3 suggests non-operative management, a score of 4 is indeterminate (operative vs. non-operative), and a score of >= 5 suggests operative management.

Question 6095

Topic: Cervical Spine

A 24-year-old male is involved in a high-speed rollover collision. CT of the cervical spine reveals a Type II odontoid fracture with a reverse obliquity fracture line (sloping from anterior-inferior to posterior-superior). Which of the following surgical interventions is considered the MOST appropriate for this fracture pattern?

. Anterior odontoid screw fixation
. Posterior C1-C2 instrumented fusion
. Rigid cervical collar for 12 weeks
. Halo vest immobilization
. C1 laminectomy

Correct Answer & Explanation

. Anterior odontoid screw fixation

Explanation

A reverse obliquity Type II odontoid fracture (fracture line angling from anteroinferior to posterosuperior) is a strict contraindication for anterior odontoid screw fixation. Attempting to place an anterior screw in this pattern will cause the fracture to shear and displace anteriorly rather than compress. The preferred surgical management for a young patient with this unstable fracture pattern is a posterior C1-C2 instrumented fusion.

Question 6096

Topic: 6. Spine

A 60-year-old male presents with progressive cervical spondylotic myelopathy localizing to the C3-C6 levels. Upright lateral cervical radiographs demonstrate a rigid cervical kyphosis of 18 degrees. Which of the following is the most appropriate primary surgical approach?

. Posterior cervical laminectomy without fusion
. Posterior cervical laminectomy and fusion
. Anterior cervical corpectomy/discectomy and fusion
. Cervical disc arthroplasty
. Posterior laminoplasty

Correct Answer & Explanation

. Posterior cervical laminectomy without fusion

Explanation

In a patient with cervical myelopathy and a rigid kyphotic deformity, an anterior approach (ACDF or corpectomy) is required to directly decompress the cord and correct the sagittal alignment. A posterior-only decompression (laminectomy or laminoplasty) is contraindicated in the setting of significant, rigid kyphosis because the spinal cord is draped tightly over the anterior pathology and will not drift back (dorsally) following a posterior procedure, thus failing to adequately relieve the compression.

Question 6097

Topic: 6. Spine

A 22-year-old female was a lap-belt restrained back-seat passenger in a high-speed frontal collision. She arrives at the trauma bay complaining of severe back pain. Imaging demonstrates a flexion-distraction injury (Chance fracture) at L2. She is neurologically intact. Due to the mechanism of injury, which of the following concomitant injuries must be actively ruled out?

. Genitourinary tract injuries
. Cardiovascular injuries
. Gastrointestinal tract injuries
. Pulmonary contusions
. Traumatic brain injury

Correct Answer & Explanation

. Genitourinary tract injuries

Explanation

Chance fractures (flexion-distraction injuries) are historically associated with the use of lap-only seatbelts. The fulcrum of flexion is anterior to the spine (at the level of the anterior abdominal wall), causing severe tension and distraction across the middle and posterior columns. Up to 40-50% of patients with a Chance fracture will have associated intra-abdominal injuries, most commonly involving hollow viscous organs (e.g., small bowel perforations, mesenteric avulsions). Careful abdominal assessment and imaging are mandatory.

Question 6098

Topic: Thoracolumbar Spine & Deformity

Which of the following describes the classic radiographic Sorensen criteria for the diagnosis of classic Scheuermann's Kyphosis?

. Anterior wedging of >= 5 degrees in 2 consecutive vertebrae
. Anterior wedging of >= 5 degrees in 3 consecutive vertebrae
. Anterior wedging of >= 10 degrees in 2 consecutive vertebrae
. Anterior wedging of >= 10 degrees in 3 consecutive vertebrae
. Schmorl's nodes in 5 consecutive vertebrae

Correct Answer & Explanation

. Anterior wedging of >= 5 degrees in 2 consecutive vertebrae

Explanation

The classic Sorensen criteria for the diagnosis of Scheuermann's Kyphosis requires structural kyphosis characterized by anterior wedging of 5 degrees or more in at least 3 adjacent (consecutive) vertebrae. Other common but non-diagnostic radiographic findings include Schmorl's nodes, endplate irregularities, and disc space narrowing.

Question 6099

Topic: 6. Spine

A 12-year-old gymnast is diagnosed with a high-grade (Meyerding Grade IV) L5-S1 dysplastic spondylolisthesis. She is planned for an instrumented reduction and interbody fusion. Which of the following nerve roots is at the highest risk of iatrogenic injury during the reduction maneuver?

. L4 nerve root
. L5 nerve root
. S1 nerve root
. S2 nerve root
. Cauda equina bundle

Correct Answer & Explanation

. L4 nerve root

Explanation

During the surgical reduction of a high-grade L5-S1 spondylolisthesis, the L5 nerve root is placed on significant stretch and is at the highest risk of iatrogenic traction injury. The exiting L5 nerve roots are anatomically vulnerable as the L5 vertebral body is pulled posteriorly and superiorly to align with the sacrum. Post-operative L5 deficits (e.g., foot drop, EHL weakness) are a known, albeit often transient, complication.

Question 6100

Topic: 6. Spine

A 62-year-old male with a 25-year history of Ankylosing Spondylitis presents to the emergency department complaining of new, severe back pain after slipping and falling on his buttocks. Initial plain radiographs of the thoracic and lumbar spine are interpreted as negative. What is the most appropriate next step in management?

. Reassurance and non-steroidal anti-inflammatory drugs (NSAIDs)
. Dual-energy X-ray absorptiometry (DEXA) scan
. CT scan of the entire spine
. Dynamic flexion-extension radiographs
. Technetium bone scan

Correct Answer & Explanation

. Reassurance and non-steroidal anti-inflammatory drugs (NSAIDs)

Explanation

Patients with Ankylosing Spondylitis (AS) have a highly rigid, osteopenic spine that acts like a long bone. Minor trauma can cause unstable, sheer-type fractures (often transdiscal or extension injuries) that are extremely difficult to visualize on plain radiographs due to the underlying deformity and ossification. Therefore, any patient with AS and new mechanical back pain after trauma must undergo advanced imaging, typically a CT scan or MRI of the entire spine, to rule out an occult, highly unstable fracture and epidural hematoma.

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