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6. Spine MCQs

Practice Set 45 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 881

Topic: 6. Spine

A 16-year-old boy presents with a rigid thoracic kyphosis measuring 75 degrees. Radiographs reveal Schmorl's nodes and endplate irregularities. According to Sorensen's criteria, what specific radiographic finding is required to confirm the diagnosis of classic Scheuermann's disease?

. Apical vertebral rotation greater than 10 degrees
. Apical wedging of exactly 1 vertebra by 10 degrees
. Lateral deviation of the spinous processes
. Anterior wedging of greater than or equal to 5 degrees in at least 3 consecutive vertebrae
. Interpedicular widening in the thoracic spine

Correct Answer & Explanation

. Anterior wedging of greater than or equal to 5 degrees in at least 3 consecutive vertebrae

Explanation

Scheuermann's kyphosis is formally defined by Sorensen's criteria as anterior wedging of at least 5 degrees in three or more consecutive vertebrae. It is associated with rigid kyphosis and endplate changes such as Schmorl's nodes.

Question 882

Topic: 6. Spine

An 8-year-old girl is evaluated for a new-onset left cavovarus foot deformity and subtle left leg atrophy. Clinical examination reveals a hairy patch over her lumbosacral spine and hyperreflexia in the lower extremities. Which of the following MRI findings is most likely responsible for her clinical presentation?

. Low-lying conus medullaris terminating at L4
. Syrinx in the cervical spine
. Herniated nucleus pulposus at L4-L5
. Arachnoid cyst at T12
. Lipoma of the filum terminale with the conus terminating at T12

Correct Answer & Explanation

. Low-lying conus medullaris terminating at L4

Explanation

The patient's clinical presentation (unilateral foot deformity, hairy patch, hyperreflexia) is highly suspicious for tethered cord syndrome. This condition is diagnosed on MRI when the conus medullaris terminates abnormally low, typically below the L2 level.

Question 883

Topic: 6. Spine

A 10-year-old girl with congenital scoliosis is noted to have a bony septum dividing the spinal cord in the sagittal plane at the T10 level on a recent CT myelogram. She is scheduled to undergo posterior spinal fusion for her progressive scoliosis. What is the critical surgical principle regarding the management of this specific anomaly?

. The bony spur should be bypassed during instrumentation
. The bony spur must be fused to the concave rod
. The spinal cord should be untethered only if neurogenic bladder develops
. Scoliosis correction should be performed first to loosen the tether
. The bony spur must be excised prior to any attempt at scoliosis correction

Correct Answer & Explanation

. The bony spur must be excised prior to any attempt at scoliosis correction

Explanation

Diastematomyelia involves a bony, cartilaginous, or fibrous septum splitting the spinal cord. To prevent catastrophic neurological injury from stretching a tethered cord, the spur must be surgically excised before any corrective maneuvers are applied to the spine.

Question 884

Topic: 6. Spine

A 2-year-old boy is diagnosed with congenital scoliosis. Based on the natural history of congenital vertebral anomalies, which of the following radiographic patterns carries the worst prognosis for rapid progression of the deformity?

. A solitary unincarcerated hemivertebra
. A unilateral unsegmented bar with a contralateral fully segmented hemivertebra
. Block vertebra involving three segments
. Bilateral fully segmented hemivertebrae
. A solitary incarcerated hemivertebra

Correct Answer & Explanation

. A unilateral unsegmented bar with a contralateral fully segmented hemivertebra

Explanation

The combination of a unilateral unsegmented bar (which prevents growth on the concavity) and a contralateral fully segmented hemivertebra (which actively grows on the convexity) leads to the most rapid and severe progression in congenital scoliosis.

Question 885

Topic: 6. Spine

A 12-year-old boy with Duchenne Muscular Dystrophy presents with a rapidly progressive 35-degree thoracolumbar scoliosis. His forced vital capacity (FVC) is currently 45% of predicted. What is the most appropriate management of his spinal deformity?

. Observation until the curve reaches 50 degrees
. Rigid TLSO bracing to prevent progression
. Posterior spinal fusion from the upper thoracic spine to the pelvis
. Anterior spinal fusion only
. Postpone surgery until FVC is strictly below 30%

Correct Answer & Explanation

. Posterior spinal fusion from the upper thoracic spine to the pelvis

Explanation

Scoliosis in Duchenne Muscular Dystrophy is aggressively progressive and bracing is poorly tolerated and ineffective. Posterior spinal fusion to the pelvis is indicated early (curves >20-30 degrees) before the FVC declines below 30%, which significantly increases perioperative mortality.

Question 886

Topic: 6. Spine

A 14-year-old male football lineman presents with 4 weeks of localized lower back pain exacerbated by lumbar extension. He denies radicular symptoms. Anteroposterior, lateral, and oblique radiographs of the lumbar spine are completely normal. What is the most appropriate next step in imaging to identify early pars interarticularis stress pathology?

. Bone scintigraphy (SPECT scan)
. MRI of the lumbar spine without contrast
. CT scan of the lumbar spine
. Dynamic flexion-extension radiographs
. Diagnostic ultrasound of the lumbar paraspinal muscles

Correct Answer & Explanation

. MRI of the lumbar spine without contrast

Explanation

MRI of the lumbar spine (specifically utilizing STIR or T2 fat-suppressed sequences) is the preferred initial advanced imaging modality to detect early pars stress edema without exposing the pediatric patient to ionizing radiation (unlike CT or SPECT).

Question 887

Topic: 6. Spine

A 16-year-old male with a known diagnosis of Marfan syndrome presents with severe, chronic back pain and intermittent lower extremity radiculopathy. Radiographs show a widened spinal canal and scalloping of the posterior vertebral bodies. Which of the following conditions is the most common spinal manifestation in this population responsible for these findings?

. Spondylolysis
. Scheuermann's kyphosis
. Arachnoid cysts
. Syringomyelia
. Dural ectasia

Correct Answer & Explanation

. Dural ectasia

Explanation

Dural ectasia, a ballooning of the dural sac due to connective tissue weakness, is the most common spinal abnormality in Marfan syndrome (present in >60% of patients). It leads to posterior vertebral body scalloping, pedicle thinning, and back/radicular pain.

Question 888

Topic: 6. Spine

A 6-year-old boy presents with a 3-week history of localized mid-back pain. He is afebrile with no neurological deficits. A lateral radiograph of the thoracic spine demonstrates a complete, uniform collapse of the T8 vertebral body (vertebra plana) with intact posterior elements. What is the most appropriate initial management?

. Urgent anterior corpectomy and strut grafting
. Posterior instrumented spinal fusion
. Observation and symptomatic management
. Chemotherapy and radiation therapy
. Broad-spectrum intravenous antibiotics

Correct Answer & Explanation

. Observation and symptomatic management

Explanation

Vertebra plana in a young child with no systemic symptoms is classic for Eosinophilic Granuloma (Langerhans cell histiocytosis). The condition is typically benign and self-limiting, with significant spontaneous reconstitution of vertebral height over time; thus, observation is the primary treatment.

Question 889

Topic: Thoracolumbar Spine & Deformity

When evaluating a pediatric patient with an L5-S1 isthmic spondylolisthesis, which of the following combinations of risk factors is most strongly associated with an increased risk of slip progression?

. High slip angle, dysplastic sacral dome, and prepubertal age
. Low slip angle, flat sacral dome, and postpubertal age
. Male gender, low pelvic incidence, and Risser 5
. High pelvic incidence, spina bifida occulta, and asymptomatic presentation
. L4-L5 location, low slip angle, and adult age

Correct Answer & Explanation

. High slip angle, dysplastic sacral dome, and prepubertal age

Explanation

Risk factors for progression of a spondylolisthesis include youth (significant growth remaining), a high slip angle (>40-50 degrees), a dysplastic (dome-shaped) sacrum, a trapezoidal L5 body, and high pelvic incidence.

Question 890

Topic: 6. Spine

A 9-year-old girl with Morquio syndrome (Mucopolysaccharidosis Type IVA) presents for a routine orthopedic evaluation. She has no acute complaints, but you note generalized joint laxity. What critical radiographic screening must be performed in this patient to prevent sudden catastrophic neurological injury?

. Thoracolumbar standing scoliosis films to rule out severe rotatory scoliosis
. Flexion-extension cervical spine films to evaluate for odontoid hypoplasia and atlantoaxial instability
. MRI of the lumbar spine to check for tethered cord
. CT scan of the pelvis to evaluate for protrusio acetabuli
. Bone scan to check for occult stress fractures

Correct Answer & Explanation

. Flexion-extension cervical spine films to evaluate for odontoid hypoplasia and atlantoaxial instability

Explanation

Patients with Morquio syndrome characteristically suffer from severe odontoid hypoplasia and ligamentous laxity. This combination leads to dangerous atlantoaxial (C1-C2) instability, mandating rigorous cervical spine screening to prevent fatal spinal cord compression.

Question 891

Topic: 6. Spine

A 10-month-old infant is diagnosed with infantile idiopathic scoliosis with a left thoracic curve of 28 degrees. Which of the following radiographic parameters described by Mehta is the most reliable predictor that this curve will progress rather than spontaneously resolve?

. Cobb angle strictly greater than 15 degrees
. Apical vertebral translation of 2 cm
. A Risser sign of 1
. A Rib-Vertebra Angle Difference (RVAD) greater than 20 degrees
. Presence of a thoracic kyphosis greater than 40 degrees

Correct Answer & Explanation

. A Rib-Vertebra Angle Difference (RVAD) greater than 20 degrees

Explanation

Mehta's Rib-Vertebra Angle Difference (RVAD) is the critical prognostic factor in infantile idiopathic scoliosis. An RVAD > 20 degrees strongly indicates a progressive curve, whereas an RVAD < 20 degrees typically indicates a resolving curve.

Question 892

Topic: 6. Spine
A 12-year-old girl with severe, rigid idiopathic scoliosis is undergoing halo-gravity traction prior to definitive spinal fusion. On hospital day 5, she complains of new-onset double vision. On examination, she is unable to abduct her left eye. What is the most likely etiology of her diplopia?
. Traction-induced Horner's syndrome
. Oculomotor nerve (CN III) palsy
. Abducens nerve (CN VI) palsy
. Trochlear nerve (CN IV) palsy
. Optic nerve (CN I) ischemia

Correct Answer & Explanation

. Abducens nerve (CN VI) palsy

Explanation

The abducens nerve (CN VI) has a long, tortuous intracranial course, making it highly susceptible to stretch injuries during halo-gravity traction. Injury results in a lateral rectus palsy, presenting as diplopia and an inability to abduct the affected eye.

Question 893

Topic: 6. Spine

A 10-year-old boy with Spinal Muscular Atrophy (SMA) Type 2 presents with a severe, collapsing "parasol" deformity of his ribs and a 90-degree neuromuscular scoliosis. He is non-ambulatory and sits in a custom wheelchair. If a spinal instrumentation and fusion is planned, failure to include the pelvis in the construct will most commonly lead to which of the following complications?

. Cervical kyphosis
. Progressive pelvic obliquity and loss of sitting balance
. Proximal junctional kyphosis
. Spinal cord tethering
. Rapid curve progression above the construct

Correct Answer & Explanation

. Progressive pelvic obliquity and loss of sitting balance

Explanation

In flaccid neuromuscular conditions like Spinal Muscular Atrophy, the spine classically collapses. If the fusion stops short of the pelvis in a non-ambulatory patient, the unbalanced spinal column will progressively tilt, leading to severe pelvic obliquity, skin breakdown, and loss of sitting balance.

Question 894

Topic: 6. Spine

A 14-year-old boy with a known diagnosis of Neurofibromatosis type 1 presents with a rapidly progressive spinal deformity. Radiographs demonstrate a 50-degree right thoracic curve that is sharply angular, accompanied by severe apical vertebral rotation, rib penciling, and vertebral wedging. Which of the following is the most appropriate surgical management for this patient?

. Anterior spinal fusion alone
. Posterior spinal fusion alone with pedicle screw construct
. Combined anterior and posterior spinal fusion
. Growth-friendly construct (e.g., growing rods)
. Anterior vertebral body tethering

Correct Answer & Explanation

. Combined anterior and posterior spinal fusion

Explanation

Dystrophic curves in NF1 are characterized by rib penciling, vertebral wedging, and sharp angulation. They have a notoriously high rate of progression and pseudoarthrosis, making combined anterior and posterior spinal fusion the gold standard of care.

Question 895

Topic: Cervical Spine

An 8-year-old girl with Down syndrome presents with a recent history of increasing clumsiness, refusal to walk long distances, and hyperreflexia in her lower extremities. Lateral flexion-extension radiographs of the cervical spine reveal an atlantodens interval (ADI) of 11 mm. What is the most appropriate management?

. Rigid cervical collar for 3 months
. Observation with serial radiographs every 6 months
. Anterior cervical discectomy and fusion
. Posterior C1-C2 fusion
. Suboccipital decompression without fusion

Correct Answer & Explanation

. Posterior C1-C2 fusion

Explanation

Symptomatic atlantoaxial instability or an ADI > 10 mm in children with Down syndrome indicates high risk for severe neurologic injury. Surgical stabilization via posterior C1-C2 fusion is the treatment of choice.

Question 896

Topic: 6. Spine

A 15-year-old boy presents with progressive mid-back pain. Lateral spine radiographs reveal a thoracic kyphosis of 75 degrees. Which of the following radiographic findings confirms the diagnosis of classic Scheuermann's disease?

. Endplate irregularity in two consecutive vertebrae
. Anterior wedging of at least 5 degrees in three consecutive vertebrae
. Schmorl's nodes in the upper lumbar spine
. Thoracic kyphosis greater than 50 degrees without anterior wedging
. Apical disc space widening

Correct Answer & Explanation

. Anterior wedging of at least 5 degrees in three consecutive vertebrae

Explanation

Sorenson's criteria for classic Scheuermann's kyphosis require anterior wedging of greater than or equal to 5 degrees in at least three contiguous vertebrae. Endplate irregularities and Schmorl's nodes are supportive but not diagnostic alone.

Question 897

Topic: 6. Spine

A 10-month-old infant is diagnosed with a left-sided thoracic idiopathic scoliosis measuring 25 degrees. Which of the following radiographic parameters indicates a high likelihood that the curve will progress rather than resolve spontaneously?

. Apical vertebral translation > 2 cm
. Cobb angle > 15 degrees
. Rib-vertebra angle difference (RVAD) > 20 degrees
. Presence of Phase 1 rib-vertebral overlap
. Sagittal thoracic kyphosis > 40 degrees

Correct Answer & Explanation

. Rib-vertebra angle difference (RVAD) > 20 degrees

Explanation

The Mehta angle, or rib-vertebra angle difference (RVAD), is crucial for prognosticating infantile idiopathic scoliosis. An RVAD > 20 degrees strongly predicts curve progression requiring intervention.

Question 898

Topic: 6. Spine
A newborn is noted to have a spinal deformity. Radiographs demonstrate a unilateral unsegmented bar with a contralateral fully segmented hemivertebra in the lower thoracic spine. Due to the high association of concurrent abnormalities, which initial imaging workup is most critical?
. Ophthalmologic examination and audiogram
. Renal ultrasound and echocardiogram
. Skeletal survey and bone density scan
. Pulmonary function testing and chest CT
. Brain MRI and electroencephalogram

Correct Answer & Explanation

. Renal ultrasound and echocardiogram

Explanation

Congenital scoliosis, especially unsegmented bars and hemivertebrae, is frequently associated with VACTERL anomalies. Screening with a renal ultrasound and echocardiogram is mandatory to rule out life-threatening cardiac and genitourinary defects.

Question 899

Topic: 6. Spine

A 10-year-old girl with a progressive 40-degree scoliosis is noted to have a cavus deformity of her right foot and a hairy patch over her lumbar spine. An MRI of the spine reveals a bony septum dividing the spinal cord at L2. What is the most appropriate sequence of treatment?

. Immediate application of a TLSO brace
. Neurosurgical resection of the bony septum prior to any scoliosis intervention
. Posterior spinal fusion followed by tethered cord release
. Simultaneous anterior spinal tethering and neurosurgical release
. Observation until skeletal maturity

Correct Answer & Explanation

. Neurosurgical resection of the bony septum prior to any scoliosis intervention

Explanation

This patient has diastematomyelia with a tethering bony spur. To prevent severe neurologic stretch injuries, the tethering structure must be resected prophylactically by neurosurgery before attempting any scoliosis correction.

Question 900

Topic: 6. Spine

A 4-year-old boy with achondroplasia presents with recent onset of central sleep apnea, hypotonia, and hyperreflexia. Radiographs of the spine show shortened pedicles and a normal cervical alignment. What is the most likely cause of his neurological symptoms?

. Atlantoaxial instability
. Severe thoracic kyphosis
. Foramen magnum stenosis
. Lumbar spinal stenosis
. Syringomyelia

Correct Answer & Explanation

. Foramen magnum stenosis

Explanation

Infants and young children with achondroplasia are at high risk for foramen magnum stenosis due to defective endochondral ossification at the skull base. This can lead to central sleep apnea, myelopathy, and sudden death if not surgically decompressed.

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