Menu

6. Spine MCQs

Practice Set 274 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 5461

Topic: 6. Spine

A patient with Kniest Dysplasia is being evaluated for spinal deformity. What is the characteristic histological finding in the growth plate cartilage of these patients?

. Large, cystic spaces described as 'Swiss cheese' appearance
. Regular columns of chondrocytes with hypertrophic zones
. PAS-positive inclusions in the chondrocytes
. Absence of the zone of provisional calcification
. Disorganized fibrocartilage with no chondrocyte lacunae

Correct Answer & Explanation

. Large, cystic spaces described as 'Swiss cheese' appearance

Explanation

Correct Answer: AKniest Dysplasia is a Type II collagenopathy. Histologically, the cartilage has a 'Swiss cheese' appearance due to large, empty spaces and a depleted matrix. Clinically, these patients have a 'dumbbell' appearance of the long bones and significant spinal involvement.

Question 5462

Topic: 6. Spine

In a patient with Achondroplasia, what is the most common cause of sudden infant death syndrome (SIDS) or respiratory arrest in early childhood?

. Restrictive lung disease from small rib cage
. Foramen magnum stenosis
. Thoracolumbar kyphosis
. Atlantoaxial instability
. Tracheomalacia

Correct Answer & Explanation

. Foramen magnum stenosis

Explanation

Correct Answer: BForamen magnum stenosis is a critical complication in infants with Achondroplasia. It can cause compression of the cervicomedullary junction, leading to central apnea, quadriparesis, and sudden death. Decompression is indicated if there are signs of myelopathy or significant narrowing on MRI.

Question 5463

Topic: 6. Spine

Which of the following skeletal dysplasias is characterized by 'corneal clouding' and 'heart valve disease' in addition to severe platyspondyly and odontoid hypoplasia?

. SED Congenita
. Morquio Syndrome
. Achondroplasia
. Diastrophic Dysplasia
. Pseudoachondroplasia

Correct Answer & Explanation

. Morquio Syndrome

Explanation

Correct Answer: BMorquio Syndrome (MPS IV) involves systemic accumulation of Keratan sulfate, which affects not only the bones (spine, epiphyses) but also the corneas (clouding) and the heart valves. This systemic involvement is a key differentiator from pure skeletal dysplasias like SED.

Question 5464

Topic: Thoracolumbar Spine & Deformity

A 12-month-old boy with diastrophic dysplasia is noted to have an isolated mid-cervical kyphosis on lateral radiographs. He has no neurological deficits. What is the expected natural history of this deformity?

. Rapid progression requiring urgent surgical fusion
. Spontaneous resolution over the next few years
. Progression to severe atlantoaxial instability
. Development of basilar invagination
. Rigid fixation of the deformity without progression

Correct Answer & Explanation

. Spontaneous resolution over the next few years

Explanation

Cervical kyphosis in diastrophic dysplasia is typically self-limiting and resolves spontaneously in the majority of cases as the child grows. Unlike Larsen syndrome, where cervical kyphosis is highly progressive and dangerous, diastrophic dysplasia usually requires only observation.

Question 5465

Topic: 6. Spine

A newborn presents with multiple large joint dislocations, spatulate thumbs, and a flattened facial profile. Lateral cervical spine radiographs reveal severe mid-cervical kyphosis. Which of the following is the most appropriate next step in management?

. Observation with serial radiographs every 6 months
. Cervical spine bracing until skeletal maturity
. Posterior cervical fusion to prevent catastrophic myelopathy
. Administration of high-dose corticosteroids
. Botulinum toxin injections for muscle spasticity

Correct Answer & Explanation

. Posterior cervical fusion to prevent catastrophic myelopathy

Explanation

Larsen syndrome is caused by a FLNB gene mutation and often presents with a highly dangerous, progressive cervical kyphosis. Early posterior cervical fusion is indicated to prevent catastrophic spinal cord compression and myelopathy.

Question 5466

Topic: Cervical Spine

A 7-year-old girl with Morquio syndrome (MPS IV) presents with progressive endurance loss and generalized hyperreflexia. Lateral flexion-extension radiographs of the cervical spine demonstrate 8 mm of atlantoaxial translation. What is the primary anatomic cause of this instability?

. Incompetence of the transverse ligament only
. Odontoid hypoplasia combined with ligamentous laxity
. Congenital absence of the C1 anterior arch
. Hypertrophy of the posterior longitudinal ligament
. Premature fusion of the C1-C2 facet joints

Correct Answer & Explanation

. Odontoid hypoplasia combined with ligamentous laxity

Explanation

In Morquio syndrome, atlantoaxial instability is characteristically caused by odontoid hypoplasia (due to defective endochondral ossification) coupled with systemic ligamentous laxity. This combination severely compromises the stability of the upper cervical spine, necessitating surgical fusion.

Question 5467

Topic: 6. Spine

An adult patient with achondroplasia presents with progressively worsening neurogenic claudication. During surgical planning for a decompressive laminectomy, which unique anatomical feature of the achondroplastic lumbar spine must be specifically addressed to prevent persistent stenosis?

. Progressive widening of the interpedicular distance from L1 to L5
. Excessively long pedicles causing ventral spinal cord tethering
. Decreased interpedicular distance from L1 to L5 with short pedicles
. Congenital absence of the pars interarticularis at multiple levels
. Massive hypertrophy of the ligamentum flavum as the primary stenotic factor

Correct Answer & Explanation

. Decreased interpedicular distance from L1 to L5 with short pedicles

Explanation

Unlike the normal spine, the interpedicular distance in achondroplasia abnormally decreases from L1 to L5. Combined with congenitally short pedicles and thickened laminae, decompression requires an extensive pedicle-to-pedicle laminectomy with undercut of the facets.

Question 5468

Topic: 6. Spine

A 3-year-old child with diastrophic dysplasia is diagnosed with cervical kyphosis. Which of the following radiographic features indicates a high likelihood of spontaneous resolution rather than progressive deformity?

. Apical vertebra located at C2-C3 with no anterior wedging
. Apical vertebra located at C6-C7 with significant spina bifida occulta
. Associated fixed atlantoaxial subluxation
. Presence of severe anterior vertebral body wedging at the apex
. Progressive widening of the posterior interspinous distance

Correct Answer & Explanation

. Presence of severe anterior vertebral body wedging at the apex

Explanation

Cervical kyphosis in diastrophic dysplasia often resolves spontaneously if the apex is high (mid-cervical, C2-C4) and lacks severe structural wedging. A lower apex, severe wedging, or widespread spina bifida occulta predicts progression requiring early fusion.

Question 5469

Topic: 6. Spine

A 12-year-old boy presents with progressive back pain, a short trunk, and a barrel chest. Lateral spine radiographs reveal generalized platyspondyly with a characteristic "heaped-up" or hump-shaped ossification in the central and posterior portions of the lumbar endplates. What is the inheritance pattern of the most likely diagnosis?

. Autosomal dominant
. Autosomal recessive
. X-linked dominant
. X-linked recessive
. Mitochondrial

Correct Answer & Explanation

. X-linked recessive

Explanation

The clinical and radiographic presentation is classic for Spondyloepiphyseal Dysplasia Tarda (SEDT). This condition is caused by a TRAPPC2 mutation and is inherited in an X-linked recessive manner, affecting males exclusively.

Question 5470

Topic: 6. Spine

An 18-month-old child presents with coarse facial features, corneal clouding, and a prominent thoracolumbar kyphosis. Based on the suspected diagnosis, lateral spine radiographs are most likely to demonstrate which of the following pathognomonic characteristics?

. Central anterior beaking of the upper lumbar vertebral bodies
. Anteroinferior beaking of the upper lumbar vertebral bodies
. Anterosuperior beaking of the upper lumbar vertebral bodies
. Coronal clefts within the thoracic vertebral bodies
. A complete absence of the pedicles in the cervical spine

Correct Answer & Explanation

. Anteroinferior beaking of the upper lumbar vertebral bodies

Explanation

The child has Hurler syndrome (MPS I). Radiographically, MPS I is characterized by hypoplasia of the anterosuperior portion of the vertebral body, resulting in a distinctive anteroinferior beak.

Question 5471

Topic: 6. Spine

A 6-year-old girl with significant short-limb dwarfism and marked ligamentous laxity presents for evaluation. She has a normal facial appearance. Genetic testing reveals a mutation in the COMP gene. What is the most common spinal manifestation requiring surgical intervention in this specific patient population?

. Thoracolumbar kyphosis
. Lumbar spinal stenosis
. Atlantoaxial instability due to odontoid hypoplasia
. Basilar invagination
. Severe, rigid, right thoracic scoliosis

Correct Answer & Explanation

. Atlantoaxial instability due to odontoid hypoplasia

Explanation

The patient has pseudoachondroplasia, characterized by normal facies and a COMP gene mutation. Unlike achondroplasia, pseudoachondroplasia frequently features odontoid hypoplasia and subsequent atlantoaxial instability, necessitating regular cervical spine screening.

Question 5472

Topic: Cervical Spine

In patients with Mucopolysaccharidoses (such as Hurler or Hunter syndromes), neurological compromise at the craniocervical junction is predominantly caused by which of the following pathomechanical factors?

. Progressive ossification of the posterior longitudinal ligament (OPLL)
. Accumulation of glycosaminoglycans leading to periodontoid soft tissue thickening
. Congenital absence of the transverse atlantal ligament
. Spontaneous resorption of the anterior arch of the atlas
. Basilar invagination due to primary osteopenia of the clivus

Correct Answer & Explanation

. Accumulation of glycosaminoglycans leading to periodontoid soft tissue thickening

Explanation

While odontoid hypoplasia contributes to instability, the primary mechanism of cervical cord compression in many MPS patients is the massive accumulation of glycosaminoglycans (GAGs) creating a thick pannus in the periodontoid soft tissues.

Question 5473

Topic: 6. Spine

A newborn presents with a severely shortened thorax and a "crab-like" appearance of the ribs on an AP chest radiograph. This is secondary to multiple posterior rib fusions and hemivertebrae. What is the most common cause of early mortality in patients with this condition?

. Cervical spine instability leading to cord transection
. Thoracic insufficiency syndrome leading to respiratory failure
. Cardiac arrhythmias from associated structural heart defects
. Renal failure due to bilateral renal agenesis
. Foramen magnum stenosis causing central apnea

Correct Answer & Explanation

. Thoracic insufficiency syndrome leading to respiratory failure

Explanation

This presentation describes spondylothoracic/spondylocostal dysostosis (Jarcho-Levin spectrum). The fused ribs and hemivertebrae prevent normal pulmonary expansion, leading to thoracic insufficiency syndrome, which is the leading cause of early mortality.

Question 5474

Topic: 6. Spine

Which of the following is a hallmark characteristic of the scoliosis that develops in patients with diastrophic dysplasia?

. High flexibility allowing for successful casting management
. Predominantly left-sided lumbar curves with low progression rates
. Extreme rigidity and a high risk of pseudoarthrosis post-fusion
. Excellent response to bracing if initiated before skeletal maturity
. Consistent spontaneous resolution if the patient is ambulatory

Correct Answer & Explanation

. Extreme rigidity and a high risk of pseudoarthrosis post-fusion

Explanation

Scoliosis in diastrophic dysplasia is notoriously rigid and rapidly progressive. Surgical correction is technically demanding, and these patients have an exceptionally high rate of pseudoarthrosis following spinal fusion.

Question 5475

Topic: 6. Spine

Following an extensive, multi-level lumbar laminectomy for severe spinal stenosis in a 45-year-old patient with achondroplasia, what is the most significant, commonly encountered postoperative complication?

. Dural tear leading to a permanent cerebrospinal fluid fistula
. Iatrogenic spinal instability requiring subsequent instrumented fusion
. Epidural hematoma causing cauda equina syndrome
. Progressive thoracic hyperkyphosis
. Heterotopic ossification of the paraspinal musculature

Correct Answer & Explanation

. Iatrogenic spinal instability requiring subsequent instrumented fusion

Explanation

Because wide, pedicle-to-pedicle decompression is required in achondroplasia, a significant portion of the facet joints is often removed. This extensive bony resection carries a high risk of postoperative iatrogenic instability, frequently requiring concurrent or delayed fusion.

Question 5476

Topic: 6. Spine
A 4-year-old girl is evaluated for asymmetric shortening of the lower extremities, congenital cataracts, and ichthyosis. Spine radiographs reveal congenital scoliosis. A review of her infantile radiographs is most likely to show which distinct finding?
. Coronal clefts of the vertebral bodies
. Bullet-shaped vertebral bodies
. Stippled calcifications of the epiphyses
. Dumbbell-shaped femora
. Central anterior beaking of the vertebrae

Correct Answer & Explanation

. Stippled calcifications of the epiphyses

Explanation

The clinical picture describes Conradi-Hรผnermann syndrome (an X-linked dominant chondrodysplasia punctata). A classic, diagnostic radiographic finding in early infancy is the presence of stippled epiphyses, which later disappear.

Question 5477

Topic: 6. Spine

A 10-year-old child presents with an unusual, waddling gait and hypermobility of the shoulders, allowing the patient to touch them anteriorly across the chest. Which of the following spinal abnormalities is most frequently associated with this patient's underlying syndrome?

. Severe atlantoaxial subluxation
. Syringomyelia and spina bifida occulta
. Thoracolumbar kyphosis with bullet vertebrae
. Basilar invagination
. Congenital fusion of the cervical spine (Klippel-Feil)

Correct Answer & Explanation

. Syringomyelia and spina bifida occulta

Explanation

The patient has cleidocranial dysplasia (RUNX2 mutation), characterized by absent or hypoplastic clavicles. Spinal manifestations are common and frequently include spina bifida occulta and syringomyelia, which may require neurosurgical intervention.

Question 5478

Topic: 6. Spine

A 2-year-old boy with achondroplasia has a persistent, rigid thoracolumbar kyphosis of 45 degrees despite physical therapy and strict avoidance of unsupported sitting. There are no neurological deficits. Radiographs show early structural wedging of the apical vertebra. What is the most appropriate next step in management?

. Continued observation as most resolve by age 5
. Extension bracing utilizing a custom TLSO
. Anterior release and interbody fusion
. Posterior instrumented spinal fusion
. Growing rod instrumentation

Correct Answer & Explanation

. Extension bracing utilizing a custom TLSO

Explanation

While infantile kyphosis in achondroplasia usually resolves with walking, persistent curves >30-40 degrees with structural wedging in a toddler require intervention. A TLSO in extension is indicated to prevent further progression and structural deformity.

Question 5479

Topic: 6. Spine

In a young child with progressively severe spondylocostal dysostosis and impending thoracic insufficiency syndrome, which surgical intervention is most widely accepted to maximize pulmonary function and manage the spinal deformity?

. Early posterior spinal fusion in situ
. Anterior convex epiphysiodesis with concave distraction
. Implantation of vertical expandable prosthetic titanium ribs (VEPTR)
. Cervicothoracic halo-gravity traction as definitive treatment
. Resection of the hemivertebrae with rigid short-segment fixation

Correct Answer & Explanation

. Implantation of vertical expandable prosthetic titanium ribs (VEPTR)

Explanation

VEPTR insertion is the standard of care for managing severe thoracic insufficiency syndrome in conditions like spondylocostal dysostosis. It indirectly corrects the spinal deformity while expanding the constricted hemithorax to allow for vital lung growth.

Question 5480

Topic: 6. Spine

A 7-year-old girl with mucopolysaccharidosis type IV (Morquio syndrome) presents with decreased endurance and myelopathic signs. Radiographs reveal severe atlantoaxial instability. What is the primary anatomic cause of this instability in this syndrome?

. Transverse ligament laxity
. Odontoid hypoplasia
. Occipital condyle hypoplasia
. Facet joint aplasia
. Ligamentum flavum hypertrophy

Correct Answer & Explanation

. Odontoid hypoplasia

Explanation

Morquio syndrome is characterized by severe odontoid hypoplasia or aplasia. Combined with inherent ligamentous laxity, this leads to profound atlantoaxial instability and potential cervical myelopathy requiring fusion.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page