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6. Spine MCQs

Practice Set 54 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 1061

Topic: 6. Spine

A 3-month-old infant is diagnosed with achondroplasia. What is the most critical neurological complication to screen for during the first year of life?

. Thoracolumbar kyphosis
. Spinal stenosis at L4-L5
. Foramen magnum stenosis
. Tethered spinal cord
. Syringomyelia

Correct Answer & Explanation

. Foramen magnum stenosis

Explanation

Foramen magnum stenosis is a life-threatening complication in infants with achondroplasia, potentially causing cervicomedullary compression, central sleep apnea, and sudden death. It requires careful clinical screening.

Question 1062

Topic: 6. Spine

A newborn presents with severe hypotonia, absent deep tendon reflexes, and paradoxical breathing. Genetic testing confirms a homozygous deletion of the SMN1 gene. What is the diagnosis and its inheritance pattern?

. Duchenne Muscular Dystrophy; X-linked recessive
. Spinal Muscular Atrophy Type 1; Autosomal recessive
. Spinal Muscular Atrophy Type 2; Autosomal dominant
. Congenital Myotonic Dystrophy; Autosomal dominant
. Charcot-Marie-Tooth Disease; Autosomal dominant

Correct Answer & Explanation

. Spinal Muscular Atrophy Type 1; Autosomal recessive

Explanation

Spinal Muscular Atrophy (SMA) Type 1 (Werdnig-Hoffmann disease) presents with severe hypotonia in early infancy and is caused by an SMN1 gene deletion. It is inherited in an autosomal recessive manner.

Question 1063

Topic: 6. Spine

A 3-year-old girl with achondroplasia develops worsening hypotonia, hyperreflexia in the lower extremities, and newly recognized central sleep apnea. What is the most crucial next step in management?

. Thoracolumbar spine MRI
. Cervical spine MRI and neurosurgical consultation
. Polysomnography follow-up in 6 months
. Growth hormone therapy
. Lower extremity deformity correction

Correct Answer & Explanation

. Cervical spine MRI and neurosurgical consultation

Explanation

These findings indicate cervicomedullary compression secondary to foramen magnum stenosis, a life-threatening complication of achondroplasia. Urgent MRI and neurosurgical decompression are required.

Question 1064

Topic: 6. Spine

Which of the following statements is true of scoliosis in patients with C harcot-Marie-Tooth disease:

. Scoliosis responds well to bracing.
. Spinal cord monitoring is usually normal.
. Scoliosis is rarely progressive.
. Thoracic curves more commonly have an apex convex to the left than the right.
. Thoracic kyphosis is less than in idiopathic scoliosis.

Correct Answer & Explanation

. Thoracic curves more commonly have an apex convex to the left than the right.

Explanation

Scoliosis is more common in patients with C harcot-Marie-Tooth disease than in the general population (between 10% to 33%). Only 15% of curves are halted by bracing. Scoliosis is commonly associated with thoracic kyphosis and with a left thoracic curve pattern. Intraoperative spinal cord monitoring is often difficult to elicit even at baseline due to the underlying neurologic disorder.

Question 1065

Topic: 6. Spine

Spinal muscular atrophy is due to a mutation in the gene for which of the following proteins:

. Dystrophin
. Survival motor neuron
. Peripheral myelin protein 22
. Frataxin
. Type I collagen

Correct Answer & Explanation

. Survival motor neuron

Explanation

Spinal muscular atrophy is due to a mutation in the survival motor neuron gene, which results in loss of many anterior horn cells of the spinal cord. Dystrophin abnormalities cause Duchenne and Becker dystrophies. Peripheral myelin protein 22 is disordered in Charcot-Marie-Tooth disease and frataxin in Friedreich ataxia. Type I collagen disorders cause structural skeletal dysplasias.

Question 1066

Topic: Cervical Spine

A 15-month-old toddler, who is neurologically intact, presents with a fracture (pic). Which of the following is the recommended treatment:

. Posterior C1-C 2 fusion
. Posterior occiput-C2 fusion
. Open reduction and screw fixation
. C 2 corpectomy and C1-C3 fusion anteriorly
. Reduction and halo vest immobilization

Correct Answer & Explanation

. Reduction and halo vest immobilization

Explanation

This odontoid physeal fracture should be treated by postural reduction and external immobilization. The reduction maneuver is posterior translation with slight axial traction, which may be accomplished by a halter or a halo vest. Immobilization must include a device such as a Minerva cast or a halo vest that can control the head well.C orrect Answer: Reduction and halo vest immobilization

Question 1067

Topic: 6. Spine



A 15-year-old sprinter presents with acute groin pain after pushing off the starting blocks. Radiographs show an avulsion fracture of the anterior inferior iliac spine (AIIS). Which muscle is responsible for this injury?

. Sartorius
. Rectus femoris
. Iliopsoas
. Hamstrings
. Gluteus minimus

Correct Answer & Explanation

. Rectus femoris

Explanation

The straight head of the rectus femoris originates at the AIIS and can avulse during forceful hip flexion and knee extension. The sartorius originates at the ASIS.

Question 1068

Topic: Thoracolumbar Spine & Deformity
This radiograph shows a 9-year-old boy with scoliosis. From which of the following conditions is the boy's scoliosis likely to have resulted?
. Marfan syndrome
. Osteogenesis imperfecta
. Neurofibromatosis
. Fibrous dysplasia
. Juvenile idiopathic scoliosis

Correct Answer & Explanation

. Neurofibromatosis

Explanation

The patient's scoliosis is the result of neurofibromatosis. A sharp focal curve over few vertebrae, thinning of apical pedicles, and spindling of the ribs are symptoms of neurofibromatosis that are indicated in the radiograph.

Question 1069

Topic: Thoracolumbar Spine & Deformity
Loeys-Dietz syndrome is caused by a mutation in:
. Fibrillin-1
. Fibrillin-2
. TGF-beta receptor
. Collagen type III
. Decorin

Correct Answer & Explanation

. TGF-beta receptor

Explanation

Loeys-Dietz syndrome is an autosomal dominant syndrome characterized by arterial tortuosity, aneurysms, hypertelorism, and bifid uvula or cleft palate. Scoliosis, foot deformities, ligamentous laxity, and other findings are often present. The aneurysms have particular risk for rupture at small diameters. This disorder is caused by mutations in genes encoding TGF-beta receptor 1 and 2.

Question 1070

Topic: Thoracolumbar Spine & Deformity

The mean age of triradiate cartilage closure in girls and boys is:

. 10 years for girls and 12 years for boys
. 11 years for girls and 12 years for boys
. 12 years for girls and 13 years for boys
. 12.5 years for girls and 13.5 years for boys
. 13.5 years for girls and 14.5 years for boys

Correct Answer & Explanation

. 12.5 years for girls and 13.5 years for boys

Explanation

The triradiate cartilage closes at a mean of 12.5 years in girls and 13.5 years in boys. The closure of the triradiate cartilage signals the end of the peak height velocity (growth spurt). This is important for timing of scoliosis treatment and for signaling a change in pelvic fracture patterns from pediatric to adult.

Question 1071

Topic: 6. Spine
An 8-year-old child with spina bifida has a focal kyphosis measuring 100° with an apex at the first lumbar vertebra and a short trunk. The patient's family is concerned about the child's risk of skin breakdown posteriorly. Recommended treatment includes:
. Milwaukee brace
. Correction in a hyperextension cast followed by a Milwaukee brace
. Posterior fusion in situ to produce correction with growth
. Anterior strut grafting
. Posterior vertebral excision and instrumentation

Correct Answer & Explanation

. Posterior vertebral excision and instrumentation

Explanation

This patient has myelokyphosis, which occurs in some patients with a thoracic level of spina bifida. The myelokyphosis is caused by a lack of posterior spinal osteoligamentous elements and denervated musculature and has a sharp, single apex with a compensatory lordosis above and below the apex. Myelokyphosis is steadily progressive with growth. Bracing and casting are ineffective treatments for patients with myelokyphosis due to the focality of the complication and insufficient skin coverage over the apex. Posterior fusion in situ is mechanically ineffective in controlling the large focal curve occurring in myelokyphosis. Anterior strut grafting in a growing child functions as an anterior bar that exacerbates the patient's myelokyphosis. A kyphectomy is the best treatment for a patient with myelokyphosis. A kyphectomy entails a posterior resection of the apical vertebra and posterior instrumentation. Posterior instrumentation corrects the cantilever. A kyphectomy does not entail fusion beyond the resected area because such a fusion impedes growth.

Question 1072

Topic: 6. Spine

Infants diagnosed with achondroplasia are at an increased risk of sudden death or severe central sleep apnea during the first year of life. This life-threatening complication is primarily due to:

. Tracheomalacia
. Foramen magnum stenosis
. Severe thoracic kyphosis
. Odontoid hypoplasia
. Cardiac septal defects

Correct Answer & Explanation

. Foramen magnum stenosis

Explanation

Foramen magnum stenosis is a critical complication in achondroplasia. It can cause cervicomedullary compression, leading to central sleep apnea, hyperreflexia, or sudden infant death, necessitating screening and possible surgical decompression.

Question 1073

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast presents with lower back pain radiating to the posterior thighs. Radiographs show a Grade 3 (75%) isthmic spondylolisthesis at L5-S1 with a high slip angle. What is the best surgical approach?

. Laminectomy alone
. Pars repair with bone grafting
. In situ posterolateral fusion from L5 to S1
. Reduction and circumferential fusion of L5-S1
. Anterior lumbar interbody fusion alone

Correct Answer & Explanation

. Reduction and circumferential fusion of L5-S1

Explanation

For high-grade (>50%) isthmic spondylolisthesis with a high slip angle or signs of sagittal imbalance, reduction and circumferential (anterior/posterior) fusion or instrumented posterior fusion with interbody support is indicated.

Question 1074

Topic: 6. Spine

A 5-year-old child with achondroplasia presents with increased waddling gait and lower back pain. Which of the following spinal pathologies is most characteristic and concerning in patients with this skeletal dysplasia?

. Cervical kyphosis with cord compression
. Thoracic scoliosis
. Foramen magnum stenosis and thoracolumbar kyphosis
. Spondyloptosis
. Atlantoaxial rotatory fixation

Correct Answer & Explanation

. Foramen magnum stenosis and thoracolumbar kyphosis

Explanation

Achondroplasia is characterized by a narrowed spinal canal and a high risk of foramen magnum stenosis (which can cause sudden death in infants) as well as symptomatic thoracolumbar kyphosis and lumbar spinal stenosis.

Question 1075

Topic: 6. Spine

A 10-month-old infant with achondroplasia presents for a routine evaluation. Which of the following orthopedic manifestations is an absolute indication for urgent surgical intervention in this patient population?

. Thoracolumbar kyphosis
. Genu varum
. Foramen magnum stenosis with cervical myelopathy
. Lumbar hyperlordosis
. Radial head subluxation

Correct Answer & Explanation

. Foramen magnum stenosis with cervical myelopathy

Explanation

Infants with achondroplasia are at high risk for foramen magnum stenosis, which can cause cervicomedullary compression, central apnea, and sudden death. Myelopathy or profound compression is an absolute indication for urgent suboccipital decompression.

Question 1076

Topic: 6. Spine
A 10-year-old girl injured her neck after falling and hitting her head. Recommended treatment includes:
. Anterior fusion C6-T1 with plate fixation
. Posterior fusion C6-T1 with plate fixation
. Anterior and posterior fusion C6-T1 with plate fixation
. Halo vest immobilization
. Cervicothoracic orthosis

Correct Answer & Explanation

. Cervicothoracic orthosis

Explanation

The patient has an anterior compression fracture of C7, which can be treated by cervicothoracic orthosis. Halo vest immobilization improves control of the head and upper cervical spine but is unnecessary treatment in this patient's case. Although an anterior operation is an optional treatment for an anterior compression fracture, it is also unnecessary in this patient's case.

Question 1077

Topic: 6. Spine

Which of the following conditions is represented in the radiograph (Slide):

. Spina bifida of the first lumbar vertebra
. Diastematomyelia
. Burst fracture
. Chance fracture
. Flexion-rotation injury

Correct Answer & Explanation

. Chance fracture

Explanation

This radiograph demonstrates a chance fracture. The posterior elements of the spine are separated, as indicated by the transverse fracture of the transverse processes, pedicles, and lamina. There is no significant element of rotation of the spine.

Question 1078

Topic: Thoracolumbar Spine & Deformity
A 15-year-old girl experienced an injury of L1 during a sledding accident. Her neurologic examination is normal. The best treatment is:
. Thoracolumbosacral orthosis
. Hyperextension cast
. Reduction and posterior fusion of T12-L1 with pedicle screws
. Corpectomy of T12 and anteroposterior instrumented fusion
. Reduction and posterior fusion of T12-L2 with pedicle screws

Correct Answer & Explanation

. Reduction and posterior fusion of T12-L2 with pedicle screws

Explanation

This patient has a Chance fracture of L1, which is indicated by the compression of the anterior portion of L1 and the distraction of the posterior portion of L1. A hyperextension cast will not treat the patient's Chance fracture completely. Operative treatment is needed to remove residual kyphosis at the thoracolumbar junction. Posterior column compression will also likely reduce the presence of residual kyphosis. Posterior fusion of T12-L2 with pedicle screws results in the best angular correction for a patient with a Chance fracture of L1. T12-L1 with hooks is an optional treatment for patients with a Chance fracture of L1 because residual kyphosis may persist even if the inferior lamina of L1 is intact.

Question 1079

Topic: 6. Spine
Which of the following conditions is represented by this computed tomography scan of a cervical spine?
. Jefferson's fracture
. Osteoid osteoma
. Odontoid fracture
. Rotatory subluxation
. Chiari malformation

Correct Answer & Explanation

. Rotatory subluxation

Explanation

Partial superimposition of C1 on C2 is present in this radiograph. C2 is the portion in the center of the frame. C1 and C2 would normally be on different cuts of a scan but are superimposed because the atlas overlaps the axis as it falls forward. If an imaginary line is drawn between the vertebral foramina of C1 and across the body of C2, an angle will form representing the degree of malrotation, which is approximately 30°.

Question 1080

Topic: 6. Spine

Which of the following conditions is not commonly associated with C hance fractures in children:

. Renal trauma
. Intestinal contusion
. Dural tear
. Neurologic injury
. Multilevel spine trauma

Correct Answer & Explanation

. Intestinal contusion

Explanation

Chance fractures in children are often associated with blunt contusions to abdominal structures. Blunt contusions to abdominal structures cause renal and intestinal trauma and distraction of the spinal cord and may be associated with dural tearing or neurologic injury. Neurologic injuries occur in fewer than half of children with Chance fractures that have blunt contusions to abdominal structures. Although spinal fractures caused by falls or axial loads can result in multilevel spinal injuries, multilevel spinal injuries do not commonly result from Chance fractures.

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