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6. Spine MCQs

Practice Set 55 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 1081

Topic: 6. Spine

Which of the following is the most common level of the fulcrum of normal cervical spine motion in a 4-year-old child?

. C1-C2
. C2-C3
. C3-C4
. C5-C6
. C7-T1

Correct Answer & Explanation

. C2-C3

Explanation

In children under 8 years of age, the fulcrum of cervical spine motion is located at C2-C3. In adults, it transitions to C5-C6, explaining the higher incidence of upper cervical injuries in young children.

Question 1082

Topic: 6. Spine
A 7-year-old child develops transient paraplegia following a motor vehicle collision. Initial trauma radiographs and CT of the spine are normal. What is the most likely diagnosis?
. Conversion disorder
. Spinal Cord Injury Without Radiographic Abnormality (SCIWORA)
. Guillain-Barrรฉ syndrome
. Central cord syndrome
. Epidural hematoma

Correct Answer & Explanation

. Spinal Cord Injury Without Radiographic Abnormality (SCIWORA)

Explanation

SCIWORA is a pediatric condition where spinal cord injury occurs without fractures or dislocations on plain films or CT. MRI is required to evaluate the spinal cord for edema or hemorrhage.

Question 1083

Topic: Thoracolumbar Spine & Deformity

A 10-year-old boy sustains a flexion-distraction injury of the lumbar spine (Chance fracture) while wearing a lap belt. Which associated injury must be specifically evaluated for?

. Aortic dissection
. Renal artery thrombosis
. Hollow viscus injury
. Pulmonary contusion
. Pelvic ring fracture

Correct Answer & Explanation

. Hollow viscus injury

Explanation

Chance fractures in children are highly associated with intra-abdominal injuries, particularly hollow viscus injuries like bowel perforations, due to the fulcrum of the lap belt over the abdomen.

Question 1084

Topic: Thoracolumbar Spine & Deformity

A 12-year-old gymnast complains of chronic low back pain. Radiographs reveal a bilateral pars interarticularis defect at L5 with a 60% anterior slip of L5 on S1. What is the most appropriate definitive management?

. Activity modification and rigid bracing
. Physical therapy and NSAIDs
. In situ posterolateral L5-S1 fusion
. Laminectomy without fusion
. Pars repair with lag screws

Correct Answer & Explanation

. In situ posterolateral L5-S1 fusion

Explanation

Symptomatic high-grade spondylolisthesis (>50% slip) in a growing child is an indication for surgical stabilization. An in situ posterolateral L5-S1 fusion is the standard of care to prevent progression and relieve symptoms.

Question 1085

Topic: Cervical Spine

Which of the following measurements is considered normal for the atlanto-dens interval (ADI) on a lateral cervical radiograph in a 6-year-old child?

. Up to 3 mm
. Up to 5 mm
. Up to 7 mm
. Up to 9 mm
. Up to 11 mm

Correct Answer & Explanation

. Up to 5 mm

Explanation

In children, an ADI of up to 4-5 mm is considered normal due to increased ligamentous laxity. In adults, the normal upper limit is 3 mm.

Question 1086

Topic: 6. Spine

A 13-year-old boy presents with severe back pain radiating down his right leg after lifting a heavy box. Straight leg raise is positive. Radiographs are normal. What condition acts as the pediatric equivalent of a disc herniation and must be considered?

. Spondylolysis
. Apophyseal ring fracture
. Scheuermann kyphosis
. Spinal epidural abscess
. Osteoid osteoma

Correct Answer & Explanation

. Apophyseal ring fracture

Explanation

An apophyseal ring fracture (slipped vertebral apophysis) occurs when the cartilaginous ring avulses from the vertebral body. It acts like a hard disc herniation in adolescents.

Question 1087

Topic: 6. Spine

A 5-year-old with Down syndrome is undergoing screening prior to participating in the Special Olympics. Flexion-extension cervical spine radiographs show an ADI of 6 mm. He is asymptomatic and neurologically intact. What is the recommendation?

. Unrestricted sports participation
. Restriction from contact sports and trampoline use
. Immediate posterior C1-C2 fusion
. Cervical collar for 6 weeks
. Halo vest application

Correct Answer & Explanation

. Restriction from contact sports and trampoline use

Explanation

An ADI > 4.5 mm in a patient with Down syndrome indicates atlantoaxial instability. If asymptomatic, they should be restricted from contact sports and high-risk activities, but surgery is not immediately indicated.

Question 1088

Topic: 6. Spine

A 3-year-old child with achondroplasia presents with delayed walking and hyperreflexia in the lower extremities. What is the most critical anatomical area to evaluate?

. Lumbar spine for stenosis
. Thoracic spine for kyphosis
. Foramen magnum for stenosis
. Cervical spine for instability
. Sacrum for agenesis

Correct Answer & Explanation

. Foramen magnum for stenosis

Explanation

Infants and young children with achondroplasia are at high risk for foramen magnum stenosis. This can cause cervicomedullary compression, resulting in hyperreflexia, sleep apnea, and potentially sudden death.

Question 1089

Topic: Thoracolumbar Spine & Deformity

A 14-year-old girl with neurofibromatosis type 1 is diagnosed with scoliosis. Her curve is short-segment and sharply angulated. Which radiographic finding suggests a dystrophic type of curve with a high risk of progression?

. Hemivertebrae
. Unilateral unsegmented bar
. Penciling of the ribs
. Bilateral pars defects
. Apophyseal ring avulsion

Correct Answer & Explanation

. Penciling of the ribs

Explanation

Dystrophic scoliosis in NF-1 is characterized by short, sharp curves, penciling of ribs, dural ectasia, and severe vertebral scalloping. These curves have a high rate of progression and pseudarthrosis.

Question 1090

Topic: 6. Spine

In a 9-year-old child, an os odontoideum is noted incidentally on cervical spine radiographs. It has smooth cortical margins. What best distinguishes it from an acute type II odontoid fracture?

. Presence of neurologic deficits
. Smooth, well-corticated margins and a hypertrophied anterior arch of C1
. Inability to perform flexion-extension views
. Age of the patient
. Location of the defect at the base of the dens

Correct Answer & Explanation

. Smooth, well-corticated margins and a hypertrophied anterior arch of C1

Explanation

Os odontoideum is characterized by smooth, corticated margins and an associated hypertrophied anterior arch of C1. This helps distinguish it from an acute fracture, which typically lacks corticated edges and C1 remodeling.

Question 1091

Topic: Cervical Spine

A 6-year-old boy presents with torticollis following a mild upper respiratory infection. He holds his head tilted to the right and rotated to the left. Radiographs reveal an atlantoaxial rotatory subluxation. According to the Fielding and Hawkins classification, a Type 1 injury is characterized by:

. Rotatory fixation with anterior displacement of the atlas 3-5 mm
. Rotatory fixation without anterior displacement of the atlas
. Rotatory fixation with anterior displacement of the atlas >5 mm
. Rotatory fixation with posterior displacement of the atlas
. Complete disruption of the transverse ligament

Correct Answer & Explanation

. Rotatory fixation without anterior displacement of the atlas

Explanation

Fielding and Hawkins Type 1 is rotatory fixation with no anterior displacement (pivot on the odontoid), representing the most common type. The transverse ligament remains intact.

Question 1092

Topic: 6. Spine

A 7-year-old boy is brought to the emergency department after a motor vehicle accident. Lateral cervical spine radiographs show a 3 mm anterior displacement of C2 on C3. Swischuk's line is evaluated to differentiate physiologic pseudosubluxation from true injury. Swischuk's line is drawn between the:

. Anterior arches of C1 and C3
. Posterior arches of C1 and C3
. Spinous processes of C1 and C3
. Spinolaminar lines of C1 and C3
. Pedicles of C1 and C3

Correct Answer & Explanation

. Spinolaminar lines of C1 and C3

Explanation

Swischuk's line is drawn from the spinolaminar line of C1 to C3. If the spinolaminar line of C2 is >2 mm anterior to this line, it indicates a true subluxation rather than physiologic pseudosubluxation.

Question 1093

Topic: 6. Spine

A 14-year-old male gymnast presents with chronic low back pain exacerbated by extension.

Imaging reveals a grade II isthmic spondylolisthesis at L5-S1. Conservative management has failed after 6 months. The most appropriate surgical treatment is:

. Laminectomy alone
. L5-S1 posterior spinal fusion with or without instrumentation
. L4-S1 posterior spinal fusion
. Pars interarticularis repair
. Anterior lumbar interbody fusion at L4-L5

Correct Answer & Explanation

. L5-S1 posterior spinal fusion with or without instrumentation

Explanation

For symptomatic grade I or II isthmic spondylolisthesis failing conservative care, an in situ L5-S1 posterior spinal fusion is the standard surgical treatment. Pars repairs are generally reserved for young patients with pars defects but no significant slip.

Question 1094

Topic: 6. Spine

A 4-year-old boy with Down syndrome is brought in for screening. Lateral cervical spine flexion-extension radiographs are obtained. Which of the following atlanto-dens intervals (ADI) is the threshold indicating potential atlantoaxial instability in this pediatric patient?

. > 2 mm
. > 3 mm
. > 5 mm
. > 8 mm
. > 10 mm

Correct Answer & Explanation

. > 5 mm

Explanation

In children, an atlanto-dens interval (ADI) greater than 5 mm is considered abnormal and indicates atlantoaxial instability. In adults, the normal threshold is stricter at >3 mm.

Question 1095

Topic: 6. Spine

A 15-year-old boy complains of mid-back pain. Lateral radiographs show a thoracic kyphosis of 55 degrees with anterior wedging of 3 consecutive vertebrae. What is the minimum degree of wedging per vertebra required to diagnose classic Scheuermann's disease (Sorensen criteria)?

. 3 degrees
. 5 degrees
. 10 degrees
. 15 degrees
. 20 degrees

Correct Answer & Explanation

. 5 degrees

Explanation

Sorensen criteria for classic Scheuermann's kyphosis require anterior wedging of at least 5 degrees in three or more consecutive vertebrae. This is usually accompanied by Schmorl's nodes and endplate irregularities.

Question 1096

Topic: 6. Spine
A 6-year-old boy presents with transient bilateral lower extremity weakness after a severe hyperextension injury of the neck during a trampoline fall. Radiographs and CT scan of the cervical spine are normal. What is the most appropriate next step in imaging?
. Repeat radiographs in 2 weeks
. Dynamic flexion-extension fluoroscopy
. MRI of the cervical spine
. CT myelogram
. Bone scan

Correct Answer & Explanation

. MRI of the cervical spine

Explanation

The patient has suspected Spinal Cord Injury Without Radiographic Abnormality (SCIWORA), which is common in children due to spinal column elasticity. An MRI is the modality of choice to evaluate the spinal cord for edema or hemorrhage.

Question 1097

Topic: 6. Spine

During the evaluation of a 6-month-old infant with an infantile idiopathic scoliosis curve of 25 degrees, the Rib-Vertebra Angle Difference (RVAD) of Mehta is measured. What RVAD value indicates a high risk for curve progression?

. < 5 degrees
. > 10 degrees
. > 20 degrees
. Phase 1 rib head relation
. < 15 degrees

Correct Answer & Explanation

. > 20 degrees

Explanation

An RVAD of greater than 20 degrees is highly indicative of a progressive curve in infantile idiopathic scoliosis. Non-progressive curves typically have an RVAD of less than 20 degrees.

Question 1098

Topic: 6. Spine
A 6-year-old boy presents with transient bilateral lower extremity weakness after a high-speed motor vehicle collision. Initial radiographs and CT of the cervical and thoracolumbar spine are completely normal. What is the most appropriate next step in management?
. Discharge with muscle relaxants
. Dynamic flexion-extension radiographs
. MRI of the whole spine
. Rigid cervical collar for 12 weeks
. Lumbar puncture

Correct Answer & Explanation

. MRI of the whole spine

Explanation

SCIWORA (Spinal Cord Injury Without Radiographic Abnormality) is common in children due to spinal column elasticity. MRI is the modality of choice to evaluate for occult spinal cord edema, hemorrhage, or ligamentous injury.

Question 1099

Topic: 6. Spine

A 5-year-old child presents after a mild fall. The lateral cervical radiograph shows 3 mm of anterior displacement of C2 on C3.

Which of the following radiographic measurements best differentiates physiological pseudosubluxation from a true traumatic injury?

. Swischuk's line passing >2 mm anterior to the posterior arch of C2
. Predental space >3 mm
. Disruption of the anterior spinal line
. Retropharyngeal space >7 mm at C2
. Kyphotic angulation >11 degrees

Correct Answer & Explanation

. Swischuk's line passing >2 mm anterior to the posterior arch of C2

Explanation

Swischuk's line is drawn connecting the anterior aspect of the C1 and C3 posterior arches. If this line passes more than 2 mm anterior to the anterior cortex of the posterior arch of C2, it indicates true pathology rather than physiological pseudosubluxation.

Question 1100

Topic: Cervical Spine
A 14-year-old boy incidentally undergoes cervical spine radiographs which reveal a well-corticated, round ossicle separated from a hypoplastic dens by a wide gap, lying cranial to the superior articular facets of the axis. What is the most likely diagnosis?
. Acute Type II Odontoid fracture
. Os odontoideum
. Acute Type III Odontoid fracture
. Persistent terminal ossicle
. Odontoid aplasia

Correct Answer & Explanation

. Os odontoideum

Explanation

Os odontoideum is characterized by a smooth, well-corticated ossicle separated from the base of the dens. It is distinct from an acute Type II fracture, which typically presents with irregular, non-corticated fracture margins.

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