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6. Spine MCQs

Practice Set 275 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 5481

Topic: 6. Spine

Which of the following cervical spine deformities is most characteristic of diastrophic dysplasia and often requires surgical intervention if it becomes rigid or progressive?

. Atlantoaxial rotatory subluxation
. Basilar invagination
. Cervical kyphosis
. Klippel-Feil anomaly
. Cervical scoliosis

Correct Answer & Explanation

. Cervical kyphosis

Explanation

Cervical kyphosis is a hallmark of diastrophic dysplasia and can be present at birth. While some cases resolve spontaneously, severe or rigid kyphosis with apical wedging and instability requires posterior, and sometimes anterior, fusion.

Question 5482

Topic: 6. Spine

A 9-year-old boy with neurofibromatosis type 1 presents with a short-segmented, sharp angular thoracic scoliosis. Radiographs show vertebral scalloping and penciling of the ribs. What is the most appropriate surgical strategy for a progressive 45-degree curve?

. Bracing until skeletal maturity
. Posterior spinal fusion alone
. Anterior and posterior spinal fusion
. Growing rod construct
. Thoracoplasty alone

Correct Answer & Explanation

. Anterior and posterior spinal fusion

Explanation

Dystrophic scoliosis in NF1 is highly progressive and carries a high risk of pseudoarthrosis and crankshaft phenomenon. Early combined anterior and posterior spinal fusion is the recommended surgical treatment to ensure stability.

Question 5483

Topic: 6. Spine
A 15-year-old with osteogenesis imperfecta type III presents with lower cranial nerve palsies, hyperreflexia, and nystagmus. Which radiographic finding of the spine and cranium is most likely responsible for these symptoms?
. Atlantoaxial subluxation
. Basilar invagination
. Thoracolumbar kyphosis
. High-grade spondylolisthesis
. C1 ring fracture

Correct Answer & Explanation

. Basilar invagination

Explanation

Basilar invagination (upward migration of the odontoid into the foramen magnum) is a severe complication of osteogenesis imperfecta. It occurs due to skull base softening, leading to brainstem and lower cranial nerve compression.

Question 5484

Topic: 6. Spine

A 35-year-old male with achondroplasia presents with neurogenic claudication. Lumbar spine MRI shows severe multi-level spinal stenosis. What anatomical abnormality is the primary driver of the stenosis in this patient?

. Hypertrophy of the ligamentum flavum
. Shortened, thickened pedicles
. Severe facet arthropathy
. Isthmic spondylolisthesis
. Ossification of the posterior longitudinal ligament

Correct Answer & Explanation

. Shortened, thickened pedicles

Explanation

Spinal stenosis in achondroplasia is primarily due to premature fusion of the neurocentral synchondroses. This results in dramatically shortened and thickened pedicles, leading to a congenitally narrow spinal canal.

Question 5485

Topic: 6. Spine

A neonate is diagnosed with Larsen syndrome characterized by multiple joint dislocations and spatulate thumbs. Which cervical spine deformity is most critical to screen for immediately to prevent sudden death?

. Atlantoaxial instability
. Subaxial cervical kyphosis
. Cervical hyperlordosis
. Basilar invagination
. Odontoid agenesis

Correct Answer & Explanation

. Subaxial cervical kyphosis

Explanation

Larsen syndrome is uniquely associated with severe cervical kyphosis. This deformity can lead to rapid and lethal cervical myelopathy if undiagnosed and left untreated in the neonatal period.

Question 5486

Topic: 6. Spine

Which of the following spinal manifestations is highly characteristic of Pseudoachondroplasia and distinguishes it clinically from Achondroplasia?

. Decreasing interpedicular distances in the lumbar spine
. Severe lumbar hyperlordosis
. Atlantoaxial instability
. Thoracolumbar kyphosis
. Foramen magnum stenosis

Correct Answer & Explanation

. Atlantoaxial instability

Explanation

Unlike achondroplasia, pseudoachondroplasia (caused by COMP mutations) is frequently associated with odontoid hypoplasia and atlantoaxial instability. This necessitates careful preoperative cervical spine screening before any surgical procedure.

Question 5487

Topic: Thoracolumbar Spine & Deformity

A 2-year-old child with Hurler syndrome presents with a prominent thoracolumbar kyphosis. Which of the following radiographic descriptions of the vertebral bodies at the apex of the kyphosis is classic for this condition?

. Coronal clefts
. Anterior inferior beaking
. Central beaking
. Anterior superior beaking
. Picture frame vertebrae

Correct Answer & Explanation

. Anterior inferior beaking

Explanation

Hurler syndrome (MPS I) classically presents with anterior inferior beaking of the vertebral bodies at the thoracolumbar junction, leading to a structural kyphosis. In contrast, Morquio syndrome typically features central beaking.

Question 5488

Topic: 6. Spine

A 12-year-old male presents with back pain and is diagnosed with X-linked Spondyloepiphyseal Dysplasia Tarda. What classic radiographic finding is typically seen in the lumbar spine of these patients?

. Rugger jersey spine
. Heaped-up appearance of the posterior vertebral endplates
. Winking owl sign
. Ivory vertebra
. Anterior wedging of all lumbar vertebrae

Correct Answer & Explanation

. Heaped-up appearance of the posterior vertebral endplates

Explanation

X-linked SED Tarda is characterized radiographically by a distinctive "heaped-up" hump-like appearance of the posterior aspect of the vertebral endplates. This typically spares the anterior portion of the vertebral body.

Question 5489

Topic: 6. Spine

A patient with delayed fontanelle closure and absent clavicles undergoes spinal imaging. Which spinal anomaly is most frequently associated with this condition?

. Cervical kyphosis
. Atlantoaxial rotatory fixation
. Spina bifida occulta
. Congenital scoliosis with hemivertebrae
. Sacral agenesis

Correct Answer & Explanation

. Spina bifida occulta

Explanation

Cleidocranial dysplasia involves defective ossification of midline structures. This delayed ossification of the neural arches frequently leads to multiple levels of spina bifida occulta, particularly in the cervical and upper thoracic spine.

Question 5490

Topic: 6. Spine

A 14-year-old with neurofibromatosis type 1 is undergoing posterior spinal fusion for dystrophic scoliosis. The anesthetist notes difficulty with neck positioning. What cervical spine abnormality is most commonly associated with dystrophic NF1?

. Cervical kyphosis
. Odontoid hypoplasia
. Os odontoideum
. Assimilation of the atlas
. Klippel-Feil syndrome

Correct Answer & Explanation

. Cervical kyphosis

Explanation

Cervical kyphosis is the most common cervical spine deformity in neurofibromatosis type 1. It can be severely progressive, distinctively angular, and often requires combined anterior and posterior fusion.

Question 5491

Topic: 6. Spine

In a 6-year-old child with achondroplasia, which of the following is an absolute indication for surgical intervention of a thoracolumbar kyphosis?

. Curve magnitude of 30 degrees
. Failure of brace treatment after 6 months
. Documented progression of a curve over 40 degrees
. Apical vertebral wedging with neurogenic deficits
. Presence of a concurrent lumbar hyperlordosis

Correct Answer & Explanation

. Apical vertebral wedging with neurogenic deficits

Explanation

Surgical intervention for thoracolumbar kyphosis in achondroplasia is indicated for severe rigid deformity, persistent apical vertebral wedging, or any associated neurological deficits. Neurogenic claudication or myelopathy is an absolute indication.

Question 5492

Topic: 6. Spine
An infant with Conradi-Hรผnermann syndrome (a form of chondrodysplasia punctata) exhibits stippled epiphyses on X-ray. What spinal complication must be aggressively monitored in this patient?
. Rapidly progressive basilar invagination
. Cervical spine instability and spinal cord compression
. Severe lumbar hyperlordosis
. Spina bifida cystica
. Isthmic spondylolisthesis

Correct Answer & Explanation

. Cervical spine instability and spinal cord compression

Explanation

Infants with chondrodysplasia punctata can develop anomalous calcifications in the cervical spine. This can lead to severe cervical instability, progressive kyphosis, and potentially lethal spinal cord compression.

Question 5493

Topic: 6. Spine

A 9-year-old patient with Maroteaux-Lamy syndrome presents with gradual onset of weakness in both legs and hyperreflexia. Given the normal intelligence characteristic of this syndrome, what is the most likely cause of the myelopathy?

. Thoracolumbar disc herniation
. Atlantoaxial instability
. Thickening of the dura mater (pachymeningitis cervicalis)
. Diastematomyelia
. Syringomyelia

Correct Answer & Explanation

. Thickening of the dura mater (pachymeningitis cervicalis)

Explanation

In MPS VI (Maroteaux-Lamy), cervical myelopathy is often driven by massive thickening of the dura mater resulting from mucopolysaccharide deposition. This, combined with hypoplastic vertebrae, causes significant spinal cord compression.

Question 5494

Topic: 6. Spine

During a multi-level laminectomy for severe spinal stenosis in a 40-year-old patient with achondroplasia, extreme care must be taken during decompression to avoid which iatrogenic complication specific to their altered anatomy?

. Vertebral artery injury
. Dural tears due to severe dural ectasia
. Iatrogenic pars interarticularis fracture leading to instability
. Excessive epidural bleeding from angiomatosis
. Injury to the spinal cord due to a tethered filum terminale

Correct Answer & Explanation

. Iatrogenic pars interarticularis fracture leading to instability

Explanation

The pedicles in achondroplasia are exceptionally short, and the pars interarticularis is spatially altered. Aggressive lateral decompression during laminectomy can easily result in iatrogenic pars fractures, necessitating concomitant spinal fusion.

Question 5495

Topic: 6. Spine

A neonate diagnosed with diastrophic dysplasia is found to have cervical kyphosis on initial radiographs. The apex of the deformity is at C3. What is the most likely natural history of this cervical deformity?

. Rapid progression to quadriparesis requiring immediate fusion
. Spontaneous resolution over the first few years of life
. Rigid stabilization with a halo vest is required for resolution
. Progression to severe scoliosis without neurological deficit
. Development of basilar invagination by age 5

Correct Answer & Explanation

. Spontaneous resolution over the first few years of life

Explanation

Cervical kyphosis in diastrophic dysplasia often resolves spontaneously, especially when the apex is in the mid-cervical spine (C3-C4). Lower cervical curves, however, are more likely to progress.

Question 5496

Topic: 6. Spine

A 2-week-old infant with multiple joint dislocations, spatulate thumbs, and a flattened midface is evaluated for spinal anomalies. Which of the following spinal deformities is classic for this syndrome and can be life-threatening if untreated?

. Atlantoaxial rotatory subluxation
. Severe cervical kyphosis
. Thoracolumbar gibbus
. Progressive neuromuscular scoliosis
. Lumbar spondylolisthesis

Correct Answer & Explanation

. Severe cervical kyphosis

Explanation

Larsen syndrome (FLNB mutation) is classically associated with severe, progressive cervical kyphosis. If left untreated, it can lead to spinal cord compression, paralysis, or death.

Question 5497

Topic: 6. Spine

A 7-year-old child presents with disproportionate short stature, waddling gait, and ligamentous laxity. Facial features are normal. Radiographs reveal platyspondyly and anterior tongue-like projections on the vertebral bodies. Which of the following is the most critical spinal complication to monitor in this patient?

. Basilar invagination
. Atlantoaxial instability
. Lumbar spinal stenosis
. Spondylolysis
. Dural ectasia

Correct Answer & Explanation

. Atlantoaxial instability

Explanation

This patient has pseudoachondroplasia (COMP mutation, normal facies). Odontoid hypoplasia leading to atlantoaxial instability is a major risk and requires regular flexion-extension radiographic screening.

Question 5498

Topic: 6. Spine

An adult patient with achondroplasia undergoes a wide laminectomy for severe neurogenic claudication. The primary anatomical cause of lumbar spinal stenosis in this patient population is:

. Hypertrophy of the ligamentum flavum
. Short, thickened pedicles with a decreasing interpedicular distance from L1 to L5
. Severe facet joint arthropathy
. Isthmic spondylolisthesis
. Congenital absence of the pars interarticularis

Correct Answer & Explanation

. Short, thickened pedicles with a decreasing interpedicular distance from L1 to L5

Explanation

In achondroplasia, the pedicles are congenitally short and thick, and the interpedicular distance abnormally decreases from L1 to L5. This narrowing is the primary driver of symptomatic lumbar spinal stenosis.

Question 5499

Topic: 6. Spine

In differentiating between mucopolysaccharidoses (MPS) based on lateral spine radiographs, which of the following best describes the classical deformity seen in Hurler Syndrome (MPS I)?

. Anterocentral beaking of the vertebral bodies
. Anteroinferior beaking of the vertebral bodies
. Anterosuperior beaking of the vertebral bodies
. Posterior scalloping with dural ectasia
. Widespread coronal clefts

Correct Answer & Explanation

. Anteroinferior beaking of the vertebral bodies

Explanation

Hurler syndrome (MPS I) typically presents with anteroinferior beaking of the lumbar vertebral bodies. In contrast, Morquio syndrome (MPS IV) is classically associated with anterocentral beaking.

Question 5500

Topic: 6. Spine

A 10-year-old girl with diastrophic dysplasia presents with progressive scoliosis. Which of the following statements regarding spinal deformity in diastrophic dysplasia is true?

. Scoliosis curves are typically flexible and respond well to orthotic management.
. Curves are often severe, rigid, and resistant to bracing, frequently requiring surgical fusion.
. Spinal deformity is rare and only occurs secondary to leg length discrepancy.
. Scoliosis typically resolves spontaneously after the pubertal growth spurt.
. Anterior spinal fusion alone is contraindicated due to severe chest wall deformities.

Correct Answer & Explanation

. Curves are often severe, rigid, and resistant to bracing, frequently requiring surgical fusion.

Explanation

Scoliosis in diastrophic dysplasia tends to appear early, progress rapidly, and become exceptionally rigid. Bracing is generally ineffective, and these rigid curves frequently require surgical stabilization.

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