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6. Spine MCQs

Practice Set 361 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 7201

Topic: 6. Spine

A neonate born with short-limbed dwarfism, cauliflower ears, and hitchhiker thumbs is being evaluated. Radiographs of the spine are obtained. Which of the following cervical spine abnormalities is highly characteristic of this specific dysplasia?

. Dystrophic scoliosis
. Decreasing interpedicular distance from L1 to L5
. Cervical kyphosis associated with spina bifida occulta
. Atlantoaxial rotatory fixation
. Severe basilar invagination

Correct Answer & Explanation

. Cervical kyphosis associated with spina bifida occulta

Explanation

Diastrophic dysplasia is caused by an SLC26A2 mutation. A characteristic finding is mid-cervical kyphosis commonly associated with localized spina bifida occulta, which uniquely tends to resolve spontaneously with growth in most cases.

Question 7202

Topic: 6. Spine

A 5-year-old child with Morquio syndrome (MPS IV) presents with progressive clumsiness, hyperreflexia, and a positive Babinski sign. What is the most common underlying cause of these neurological findings in this patient population?

. Short, thick pedicles causing central canal stenosis
. Foramen magnum stenosis from achondroplasia-like skull base changes
. Odontoid hypoplasia and ligamentous laxity causing atlantoaxial instability
. Inferior anterior vertebral beaking causing severe thoracolumbar kyphosis
. Basilar invagination secondary to osteomalacia

Correct Answer & Explanation

. Odontoid hypoplasia and ligamentous laxity causing atlantoaxial instability

Explanation

Morquio syndrome uniquely features severe ligamentous laxity combined with odontoid hypoplasia. This results in dangerous atlantoaxial instability that can cause progressive cervical myelopathy, requiring strict monitoring and often prophylactic fusion.

Question 7203

Topic: 6. Spine

A 3-year-old child presents with coarse facial features, hepatosplenomegaly, and corneal clouding. Alpha-L-iduronidase deficiency is confirmed. Which of the following radiographic findings is most characteristic of the spine in this specific mucopolysaccharidosis?

. Central anterior beaking of the vertebral bodies
. Odontoid hypertrophy
. Decreasing interpedicular distance in the lumbar spine
. Inferior anterior beaking of the lumbar vertebrae
. Congenital rotatory scoliosis

Correct Answer & Explanation

. Inferior anterior beaking of the lumbar vertebrae

Explanation

Hurler syndrome (MPS I) is characterized by inferior anterior beaking of the vertebral bodies, which contributes to thoracolumbar kyphosis. In contrast, Morquio syndrome (MPS IV) typically exhibits central anterior beaking.

Question 7204

Topic: 6. Spine

A 6-year-old boy with a known COL2A1 gene mutation and spondyloepiphyseal dysplasia congenita (SEDC) requires a routine tonsillectomy. Which of the following must be ruled out prior to clearing the patient for general anesthesia?

. Odontoid hypoplasia leading to atlantoaxial instability
. Sacral agenesis
. Foramen magnum stenosis
. High-grade dysplastic spondylolisthesis
. Severe thoracic lordosis

Correct Answer & Explanation

. Odontoid hypoplasia leading to atlantoaxial instability

Explanation

Patients with SEDC have a high incidence of odontoid hypoplasia and os odontoideum, leading to atlantoaxial instability. Flexion-extension cervical spine radiographs are mandatory prior to general anesthesia to prevent catastrophic spinal cord injury during intubation.

Question 7205

Topic: 6. Spine

An 8-year-old female with known neurofibromatosis type 1 (NF1) presents with a rapidly progressive spinal deformity. Which of the following radiographic descriptions is most characteristic of dystrophic scoliosis in this condition?

. A long, sweeping thoracolumbar C-shaped curve
. Severe platyspondyly with central beaking
. A short, sharp-angled curve with vertebral scalloping and rib penciling
. A congenital hemivertebra with a unilateral unsegmented bar
. A progressive decreasing interpedicular distance

Correct Answer & Explanation

. A short, sharp-angled curve with vertebral scalloping and rib penciling

Explanation

Dystrophic scoliosis in NF1 is characterized by a short, sharp-angled curve. Associated dystrophic radiographic features include dural ectasia causing posterior vertebral scalloping, rib penciling, and severe apical rotation.

Question 7206

Topic: 6. Spine

A 9-year-old boy with neurofibromatosis type 1 (NF1) is diagnosed with a 45-degree dystrophic scoliosis. The curve has progressed 15 degrees over the last six months. What is the most highly recommended surgical strategy for this patient?

. Full-time rigid bracing until skeletal maturity
. Posterior spinal fusion with instrumentation alone
. Growth-friendly constructs (e.g., VEPTR)
. Combined anterior and posterior spinal fusion
. In situ posterior sublaminar wiring

Correct Answer & Explanation

. Combined anterior and posterior spinal fusion

Explanation

Dystrophic scoliosis in NF1 has a notoriously high risk of pseudarthrosis and continued progression even after solid posterior fusion (crankshaft phenomenon). Combined anterior and posterior spinal fusion is the gold standard for these aggressive curves.

Question 7207

Topic: 6. Spine

A 7-year-old girl with a normal facial appearance presents with disproportionate short stature, a waddling gait, and joint laxity. Genetic testing reveals a mutation in the cartilage oligomeric matrix protein (COMP) gene. Which of the following spinal pathologies is most critical to monitor in this patient?

. Odontoid hypoplasia and atlantoaxial instability
. Severe foramen magnum stenosis
. Cervical kyphosis with an associated neural tube defect
. Basilar invagination
. Decreasing interpedicular distance from L1 to L5

Correct Answer & Explanation

. Odontoid hypoplasia and atlantoaxial instability

Explanation

This patient has pseudoachondroplasia (COMP mutation, normal facies). Like SEDC and Morquio, pseudoachondroplasia carries a significant risk of odontoid hypoplasia and subsequent atlantoaxial instability, requiring careful monitoring.

Question 7208

Topic: 6. Spine

A newborn presents with multiple large joint dislocations, spatulate thumbs, and a depressed nasal bridge. Filamin B (FLNB) gene mutation is confirmed. What is the most catastrophic spinal complication associated with this syndrome?

. Severe cervical kyphosis leading to progressive myelopathy
. Rapidly progressive thoracolumbar scoliosis
. Congenital atlanto-occipital dissociation
. High-grade L5-S1 spondylolysis
. Foramen magnum stenosis causing central sleep apnea

Correct Answer & Explanation

. Severe cervical kyphosis leading to progressive myelopathy

Explanation

Larsen syndrome (FLNB mutation) is characterized by multiple joint dislocations and spatulate thumbs. The most dangerous manifestation is severe cervical kyphosis, which can lead to rapid, profound cervical myelopathy and often requires early posterior and/or anterior fusion.

Question 7209

Topic: 6. Spine
A 25-year-old patient with osteogenesis imperfecta type III presents with new-onset lower cranial nerve palsies, occipital headaches, and bilateral hyperreflexia. Given the underlying bone pathology, what is the most likely diagnosis?
. Atlantoaxial rotatory subluxation
. Spontaneous cervical epidural hematoma
. Basilar invagination
. Dystrophic scoliotic progression into the cervical spine
. Pathologic fracture of the C5 vertebra

Correct Answer & Explanation

. Basilar invagination

Explanation

In severe forms of osteogenesis imperfecta, the generalized osteopenia affects the skull base. Upward migration of the odontoid through the softened foramen magnum (basilar invagination) causes compression of the brainstem and lower cranial nerves.

Question 7210

Topic: 6. Spine

A 4-year-old child with diastrophic dysplasia is noted to have a progressive cervical kyphosis measuring 60 degrees. The anomaly is associated with a mutation in the SLC26A2 gene. Which of the following represents the most appropriate management for this specific spinal deformity?

. Halo gravity traction followed by observation
. Observation until skeletal maturity
. Posterior cervical spinal fusion
. Anterior cervical discectomy and fusion
. Cervicothoracic orthosis (CTO) bracing

Correct Answer & Explanation

. Posterior cervical spinal fusion

Explanation

While mild cervical kyphosis in diastrophic dysplasia may resolve, severe progressive kyphosis (especially >50 degrees) is life-threatening and can cause catastrophic myelopathy. Early posterior cervical spinal fusion is required to halt progression and prevent neurologic compromise.

Question 7211

Topic: 6. Spine

A 5-year-old child presents with disproportionate short stature, normal facies, and a waddling gait. Radiographs show platyspondyly with anterior tongue-like projections of the vertebral bodies, as well as delayed ossification of the capital femoral epiphyses. Genetic testing confirms a COMP gene mutation. Which of the following spinal conditions is this patient at highest risk of developing?

. Severe progressive idiopathic-like scoliosis
. Atlantoaxial instability
. High-grade dysplastic spondylolisthesis
. Rigid thoracolumbar kyphosis requiring fusion
. Ankylosing of the sacroiliac joints

Correct Answer & Explanation

. Atlantoaxial instability

Explanation

This patient has pseudoachondroplasia, caused by a mutation in the COMP gene, characterized by normal facies and anterior tongue-like vertebral projections. Similar to SEDc, these patients have a high risk of odontoid hypoplasia leading to atlantoaxial instability.

Question 7212

Topic: 6. Spine
A 12-year-old patient with osteogenesis imperfecta type III presents with new-onset lower extremity hyperreflexia, sleep apnea, and swallowing difficulties. What is the most likely structural spinal pathology responsible for these symptoms?
. Atlantoaxial rotatory subluxation
. Severe upper thoracic scoliosis
. Basilar invagination
. Progressive thoracolumbar kyphosis
. Lumbar spinal stenosis

Correct Answer & Explanation

. Basilar invagination

Explanation

Basilar invagination occurs when the odontoid process migrates upward into the foramen magnum due to skull base softening, often seen in severe osteogenesis imperfecta. It causes brainstem compression resulting in cranial nerve deficits, apnea, and myelopathy.

Question 7213

Topic: 6. Spine

A 50-year-old male with achondroplasia presents with severe neurogenic claudication refractory to conservative management. He is scheduled for a lumbar decompression. Due to the unique pathoanatomy of the achondroplastic spine, which of the following surgical techniques is specifically required to achieve adequate decompression?

. Routine central laminectomy sparing the facet joints
. Anterior lumbar interbody fusion at all affected levels alone
. Decompression extending into the lateral recesses with partial or complete pediculectomy
. Laminoplasty using allograft bone blocks
. Interspinous process distraction device placement

Correct Answer & Explanation

. Decompression extending into the lateral recesses with partial or complete pediculectomy

Explanation

In achondroplasia, spinal stenosis is primarily caused by congenitally short, thickened pedicles and decreased interpedicular distance. Effective decompression requires wide unroofing of the lateral recesses, often necessitating a partial or complete pediculectomy to free the exiting nerve roots.

Question 7214

Topic: 6. Spine

A newborn presents with multiple large-joint dislocations, spatulate thumbs, and a depressed nasal bridge. Radiographs confirm bilateral knee, hip, and elbow dislocations. What cervical spine anomaly is characteristic of this syndrome and requires urgent evaluation?

. Atlanto-occipital assimilation
. Cervical kyphosis with hypoplastic vertebrae
. Odontoid hypoplasia
. Basilar invagination
. Coronal cleft vertebrae

Correct Answer & Explanation

. Cervical kyphosis with hypoplastic vertebrae

Explanation

This clinical picture describes Larsen syndrome, associated with mutations in the FLNB gene. Patients frequently present with a sharp, severe cervical kyphosis involving hypoplastic vertebrae that can lead to rapid spinal cord compression if not identified and stabilized early.

Question 7215

Topic: 6. Spine

A neonate is evaluated in the NICU for short-limbed dwarfism, ichthyosis, and distinctive stippled calcifications around the epiphyses on plain radiographs. Lateral radiographs of the spine are most likely to demonstrate which of the following characteristic findings?

. Coronal clefts of the vertebral bodies
. Anterior inferior beaking
. Severe central canal stenosis
. Absence of the sacrum
. Sagittal clefts (butterfly vertebrae)

Correct Answer & Explanation

. Coronal clefts of the vertebral bodies

Explanation

The patient has chondrodysplasia punctata, characterized by ichthyosis, short-limbed dwarfism, and stippled epiphyses. A classic radiographic hallmark of this condition in the spine is the presence of coronal clefts within the vertebral bodies.

Question 7216

Topic: 6. Spine

A 14-year-old boy with Neurofibromatosis Type 1 presents with a sharp, angular thoracic scoliosis of 65 degrees and neck stiffness. What cervical spine abnormality is most frequently associated with the severe dystrophic spinal changes seen in NF1?

. Atlantoaxial instability
. Odontoid hypoplasia
. Severe progressive cervical kyphosis
. Congenital cervical stenosis
. Klippel-Feil segmentation anomalies

Correct Answer & Explanation

. Severe progressive cervical kyphosis

Explanation

Dystrophic spinal changes in Neurofibromatosis Type 1 often produce sharp, angular, and highly progressive deformities. In the cervical spine, this classically manifests as a severe and rigid cervical kyphosis that requires early surgical intervention to prevent myelopathy.

Question 7217

Topic: 6. Spine

A 6-year-old girl with normal intelligence presents with short trunk dwarfism, knock-knees, and a barrel chest. Flexion-extension cervical spine radiographs reveal significant atlantoaxial instability. Which of the following accumulated substances is most directly related to her condition?

. Heparan sulfate
. Dermatan sulfate
. Keratan sulfate
. Hyaluronic acid
. Sphingomyelin

Correct Answer & Explanation

. Keratan sulfate

Explanation

Morquio syndrome (MPS IV) uniquely features normal intelligence with severe skeletal dysplasia, notably atlantoaxial instability due to odontoid hypoplasia. It is characterized by the accumulation of keratan sulfate.

Question 7218

Topic: 6. Spine

A 2-year-old child presents with severe developmental delay, corneal clouding, and flexion contractures of the fingers. Radiographs of the spine demonstrate anterior beaking of the lumbar vertebral bodies.

Deficiency of which of the following enzymes is responsible for this condition?

. Alpha-L-iduronidase
. Iduronate-2-sulfatase
. Heparan N-sulfatase
. Galactosamine-6-sulfatase
. Arylsulfatase B

Correct Answer & Explanation

. Alpha-L-iduronidase

Explanation

Hurler syndrome (MPS I) features severe cognitive decline, corneal clouding, trigger digits, and anterior vertebral beaking. It is caused by an autosomal recessive deficiency of alpha-L-iduronidase.

Question 7219

Topic: Cervical Spine

A 6-year-old boy presents with short stature, severe genu valgum, and corneal clouding, but displays normal intelligence. Radiographs reveal generalized platyspondyly and marked odontoid hypoplasia. Which of the following is the specific enzyme deficient in this patient's condition?

. Alpha-L-iduronidase
. Iduronate-2-sulfatase
. N-acetylgalactosamine-6-sulfatase
. Arylsulfatase B
. Heparan N-sulfatase

Correct Answer & Explanation

. N-acetylgalactosamine-6-sulfatase

Explanation

This patient has Morquio syndrome A (MPS IV A), characterized by normal intelligence, severe skeletal dysplasia, and profound cervical instability due to odontoid hypoplasia. It is caused by a deficiency in N-acetylgalactosamine-6-sulfatase.

Question 7220

Topic: Thoracolumbar Spine & Deformity

A 2-year-old presents with coarse facial features, hepatosplenomegaly, and a progressive thoracolumbar kyphosis. Radiographs reveal thick, paddle-shaped ribs and hypoplastic "bullet-shaped" vertebral bodies. Enzyme analysis shows a deficiency of alpha-L-iduronidase. Which of the following best describes this syndrome?

. Hunter syndrome
. Hurler syndrome
. Sanfilippo syndrome
. Morquio syndrome
. Spondyloepiphyseal dysplasia congenita

Correct Answer & Explanation

. Hurler syndrome

Explanation

Hurler syndrome (MPS I) is characterized by coarse facies, dysostosis multiplex, intellectual disability, and alpha-L-iduronidase deficiency. Bullet-shaped vertebrae and paddle-shaped ribs are classic radiographic findings of dysostosis multiplex.

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