6. Spine MCQs

A 70-year-old man undergoes a primary total hip arthroplasty. He has a history of a solid instrumented lumbar fusion from L2 to the sacrum. How does this spinal pathology affect his spinopelvic biomechanics and subsequent dislocation risk during sitting?

A 6-year-old boy presents with back pain and a solitary 'punched-out' lytic lesion in his skull. Spine radiographs show a complete collapse of the T8 vertebral body (vertebra plana). Biopsy reveals cells with reniform nuclei and eosinophilic cytoplasm, intermixed with eosinophils. Which marker is diagnostic?

A 7-year-old boy complains of severe neck pain. Radiographs reveal flattening of the C3 vertebral body (vertebra plana).

Biopsy reveals cells with grooved nuclei resembling coffee beans, mixed with eosinophils. Electron microscopy of the neoplastic cells would most likely demonstrate:

A 30-year-old female sustains a Denis Zone 3 sacral fracture following a fall from height. Which of the following is the most likely neurologic complication associated with this specific injury pattern?

A 22-year-old baseball pitcher undergoes an ulnar collateral ligament (UCL) reconstruction. The anterior bundle of the UCL is the primary restraint to valgus stress. Which specific band of the anterior bundle provides the primary restraint during early flexion (0 to 60 degrees)?

A 10-year-old child presents with diffuse joint pain, bleeding gums, and petechiae. Radiographs show a prominent white line of Frankel at the metaphyses. The underlying defect is a failure of which step in collagen synthesis?

A 65-year-old male with a history of a multilevel lumbar spinal fusion (L2-S1) presents for a primary total hip arthroplasty. Because his spine is functionally stiff and fixed in a 'flatback' (decreased lumbar lordosis) posture, his pelvis cannot properly retrovert when transitioning from standing to sitting. How should the surgeon adjust the acetabular component positioning to minimize the risk of posterior dislocation?

A 68-year-old male with severe ankylosing spondylitis and a fused lumbar spine is planned for a primary total hip arthroplasty. How should the surgeon alter the standard acetabular cup positioning to minimize the risk of posterior dislocation?

A 68-year-old female presents for a primary total hip arthroplasty. Preoperative radiographs reveal a long spinal fusion from T10 to the pelvis with a significantly decreased sacral slope and a retroverted pelvis. Based on her spinopelvic mechanics, this patient is at the greatest risk for which of the following complications?

A 6-year-old boy presents with back pain and is found to have a severe compression fracture (vertebra plana) of T8 on radiographs. Biopsy of the lesion shows histiocytes with grooved, 'coffee-bean' nuclei, mixed with eosinophils. Electron microscopy reveals Birbeck granules. Which marker is most reliably positive on immunohistochemistry?

A 7-year-old boy presents with back pain. Radiographs demonstrate a flattened vertebral body (vertebra plana) at T10. Biopsy reveals a proliferation of mononuclear cells with grooved nuclei mixed with eosinophils. Immunohistochemistry will most likely be positive for which of the following markers?

A 7-year-old boy presents with back pain. Radiographs reveal a completely flattened T8 vertebral body (vertebra plana). Needle biopsy demonstrates an infiltrate of eosinophils mixed with prominent histiocytes that have folded, 'coffee-bean' shaped nuclei. Which of the following immunohistochemical markers is the most highly specific for the primary pathologic cell in this condition?

A 6-year-old boy presents with localized back pain. Radiographs demonstrate a 'vertebra plana' in the thoracic spine. Biopsy of the lesion shows a proliferation of cells with distinct nuclear grooves, admixed with eosinophils. Electron microscopy identifies tennis-racket shaped organelles. Which immunohistochemical marker will definitively identify the lesional cells?

A 7-year-old boy presents with severe localized thoracic back pain. Radiographs reveal uniform flattening of the T7 vertebral body (vertebra plana) with preserved adjacent disc spaces. Biopsy shows a cellular infiltrate including eosinophils and mononuclear cells with grooved, 'coffee-bean' nuclei. Electron microscopy is most likely to reveal which of the following?

A 4-year-old boy with achondroplasia presents with clumsiness, increased sleeping, and hyperreflexia in the lower extremities. Which of the following is the most likely etiology of his new neurologic findings?

A 15-year-old gymnast complains of chronic low back pain exacerbated by extension. Oblique radiographs demonstrate a "Scotty dog with a collar" appearance at L5. A bilateral pars interarticularis defect is confirmed. If conservative management fails, which of the following is the most appropriate surgical intervention for an isolated L5 pars defect without spondylolisthesis in this young athlete?

A 9-month-old infant is incidentally noted to have a left-sided thoracic scoliosis measuring 25 degrees. To differentiate between a resolving and a progressive infantile idiopathic scoliosis, the rib-vertebra angle difference (RVAD) of Mehta is measured at the apical vertebra. An RVAD greater than what value is highly predictive of curve progression?

A 15-year-old competitive gymnast presents with worsening lower back pain that is exacerbated by leaning backward. Radiographs and subsequent MRI confirm a bilateral pars interarticularis defect at L5 without spondylolisthesis.

This injury (spondylolysis) is primarily the result of repetitive mechanical stress applied during which combination of spinal motions?

A 2-year-old child is diagnosed with congenital scoliosis. Radiographic evaluation of the spine reveals a unilateral unsegmented bar with a fully segmented hemivertebra at the same level on the contralateral side.

What is the expected natural history of this specific spinal anomaly if left untreated?