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 5081
Topic: 6. Spine
A 16-year-old male diver reports 3 months of central low back pain that worsens with back extension. Oblique lumbar radiographs reveal a radiolucent line across the pars interarticularis of L5 (the 'collar on the Scotty dog'). Neurologic exam is normal. What is the recommended initial management?
Correct Answer & Explanation
. Rigid TLSO bracing, activity modification, and physical therapy
Explanation
This adolescent athlete has symptomatic spondylolysis. First-line management is strictly nonoperative, emphasizing activity restriction, bracing (e.g., TLSO) to limit extension, and core-strengthening physical therapy.
Question 5082
Topic: 6. Spine
A 15-year-old female gymnast complains of an insidious onset of mechanical lower back pain that is notably exacerbated by lumbar extension. Oblique lumbar radiographs reveal a lucency at the pars interarticularis of L5. What is the recommended initial management?
Correct Answer & Explanation
. Activity restriction, bracing, and core stabilization physical therapy
Explanation
The patient presents with symptomatic spondylolysis. The standard initial treatment for uncomplicated spondylolysis in a young athlete consists of cessation of the offending activity, temporary bracing, and a physical therapy regimen focused on core and pelvic stabilization.
Question 5083
Topic: Thoracolumbar Spine & Deformity
A 13-year-old female competitive gymnast presents with progressive low back pain and bilateral radicular symptoms radiating to the posterior thighs. Examination reveals a palpable 'step-off' at the lumbosacral junction, a crouched gait, and severe hamstring tightness. Standing lateral radiographs reveal a Meyerding Grade III isthmic spondylolisthesis at L5-S1 with a slip angle of 45 degrees. What is the most appropriate definitive management?
Correct Answer & Explanation
. Posterior spinal decompression, reduction of the slip, and L5-S1 instrumented fusion
Explanation
The patient has a high-grade (Meyerding Grade III, >50% slip) isthmic spondylolisthesis with a high slip angle, clinical deformity, and neurologic symptoms. High-grade slips with radicular symptoms and sagittal imbalance in adolescents mandate surgical intervention. The contemporary standard involves posterior spinal decompression (to relieve the L5 roots), partial or complete reduction of the slip (to restore sagittal balance), and instrumented fusion (L5-S1 or L4-S1 depending on the specific anatomy). Pars repair is reserved for low-grade slips (Grade I) without disc degeneration. In situ fusion in the setting of a high slip angle carries an unacceptable risk of pseudarthrosis and progressive deformity.
Question 5084
Topic: 6. Spine
A 3-year-old boy presents with a noticeable spinal curvature. Standing full-spine radiographs demonstrate a unilateral unsegmented bar spanning from T8 to T10, with a contralateral fully segmented hemivertebra at T9.
What is the expected natural history of this specific spinal anomaly if left untreated?
Correct Answer & Explanation
. Rapid progression of 5-10 degrees per year
Explanation
This patient has congenital scoliosis. The combination of a unilateral unsegmented bar with a contralateral fully segmented hemivertebra at the same level represents the most aggressive form of congenital scoliosis. Because there is absent growth on the concavity (the bar) and excessive growth on the convexity (the hemivertebra), this deformity has a relentless natural history, typically progressing at a rapid rate of 5 to 10 degrees per year. Early surgical intervention (such as hemivertebra excision and short segment fusion) is indicated.
Question 5085
Topic: 6. Spine
A 13-year-old boy with Duchenne Muscular Dystrophy (DMD) presents for evaluation. He lost the ability to ambulate 18 months ago and is wheelchair-dependent. Examination reveals poor sitting balance and a progressive spinal deformity. Radiographs demonstrate a neuromuscular scoliosis of 45 degrees extending from T4 to the pelvis. His current forced vital capacity (FVC) is 40% of predicted. What is the most appropriate management for his spinal deformity?
Correct Answer & Explanation
. Posterior spinal fusion from the upper thoracic spine to the pelvis
Explanation
In patients with Duchenne Muscular Dystrophy, scoliosis is virtually inevitable once they become wheelchair-bound and it progresses rapidly. Bracing is contraindicated as it does not halt progression and worsens restrictive lung disease. Surgical stabilization is recommended early (curves >20-30 degrees) before the patient's pulmonary function declines to a prohibitively dangerous level. The standard surgical procedure is a posterior spinal fusion from the upper thoracic spine down to the pelvis to correct pelvic obliquity, maintain sitting balance, and improve quality of life. An FVC >30-35% is generally considered adequate to proceed with surgery.
Question 5086
Topic: 6. Spine
A 4-year-old girl is brought to the emergency department after a minor fall. Her lateral cervical spine radiograph shows 3 mm of anterior displacement of C2 on C3. Swischuk's line is drawn from the anterior aspect of the C1 spinous process to the anterior aspect of the C3 spinous process. The anterior aspect of the C2 spinous process touches this line. What is the most appropriate management?
Correct Answer & Explanation
. Observation and discharge as this is a normal variant
Explanation
Pseudosubluxation of C2 on C3 is a normal physiologic variant in young children due to ligamentous laxity. A normal Swischuk line (the C2 spinous process is within 1-2 mm of the line) confirms this is not a true traumatic subluxation.
Question 5087
Topic: Thoracolumbar Spine & Deformity
A 14-year-old gymnast presents with chronic lower back pain that radiates to her posterior thighs. Radiographs reveal a grade III L5-S1 isthmic spondylolisthesis. She has failed 6 months of conservative management. What is the most appropriate surgical treatment?
Correct Answer & Explanation
. L5-S1 posterior lateral in situ fusion
Explanation
High-grade (Grade III or IV) or symptomatic slipped dysplastic spondylolisthesis failing non-operative care requires surgical stabilization. L5-S1 posterolateral fusion (with or without instrumentation/reduction) is the standard treatment.
Question 5088
Topic: 6. Spine
A 12-year-old girl presents with adolescent idiopathic scoliosis. Her primary right thoracic curve measures 25 degrees. She has not reached menarche. Hand radiograph shows a Sanders bone age stage of 2 (early adolescent growth phase). What is her estimated risk of curve progression to >50 degrees, and what is the best treatment?
Correct Answer & Explanation
. 60-80%; rigid TLSO bracing
Explanation
A 25-degree curve in a premenarchal female at Sanders stage 2 has a high risk of progression (roughly 60-80%). Rigid thoracolumbosacral orthosis (TLSO) bracing is indicated for curves between 25-40 degrees in highly immature patients to prevent progression to surgical magnitude.
Question 5089
Topic: 6. Spine
A newborn male is noted to have a short webbed neck, low posterior hairline, and severely limited cervical range of motion. Radiographs demonstrate fusion of multiple cervical vertebrae. Which of the following conditions must be urgently evaluated in this patient?
Correct Answer & Explanation
. Cervical spine instability and spinal cord compression
Explanation
Klippel-Feil syndrome is characterized by congenital fusion of cervical vertebrae. The most critical and potentially life-threatening associated issue is cervical spine instability (often at adjacent unfused segments or the atlantoaxial junction), requiring careful evaluation to prevent spinal cord injury.
Question 5090
Topic: 6. Spine
A 14-year-old gymnast presents with persistent low back pain. Radiographs demonstrate a Grade II isthmic spondylolisthesis at L5-S1. She has failed 6 months of physical therapy and bracing. Which of the following is the most appropriate surgical intervention?
Correct Answer & Explanation
. L5-S1 posterior spinal fusion
Explanation
For a symptomatic Grade II isthmic spondylolisthesis that has failed conservative management, an L5-S1 posterior spinal fusion is the standard of care. Direct pars repair is generally reserved for Grade I slips or isolated pars defects.
Question 5091
Topic: 6. Spine
A 14-year-old female gymnast with chronic back pain has failed 6 months of non-operative management. Radiographs reveal an isthmic spondylolisthesis at L5-S1 with a 60% anterior slip (Meyerding Grade III). What is the most appropriate surgical treatment?
Correct Answer & Explanation
. L5-S1 instrumented posterior spinal fusion
Explanation
High-grade isthmic spondylolisthesis (Meyerding Grade III or higher, >50% slip) that is symptomatic and recalcitrant to conservative care requires surgical stabilization. L5-S1 or L4-S1 instrumented posterior spinal fusion, with or without reduction, is the standard of care.
Question 5092
Topic: 6. Spine
A 12-year-old non-ambulatory boy with Duchenne muscular dystrophy (DMD) has developed a progressive scoliosis of 35 degrees. His forced vital capacity (FVC) is 45% of predicted. What is the most widely accepted orthopaedic management for this patient's spinal deformity?
Correct Answer & Explanation
. Posterior spinal fusion from the upper thoracic spine down to the pelvis
Explanation
In Duchenne muscular dystrophy, spinal deformity is relentlessly progressive once the patient becomes wheelchair-bound. Bracing is ineffective and poorly tolerated. Early posterior spinal fusion extending to the pelvis is indicated to maintain sitting balance and optimize pulmonary function.
Question 5093
Topic: 6. Spine
A 9-month-old boy is referred for a left-sided thoracic scoliosis. Upright radiographs demonstrate a 25-degree curve. Measurement of the rib-vertebra angle difference (RVAD) of Mehta at the apical vertebra is 25 degrees. Based on these findings, what is the most likely natural history and the appropriate next step in management?
Correct Answer & Explanation
. High risk of progression requiring serial Mehta casting
Explanation
Infantile idiopathic scoliosis with a rib-vertebra angle difference (RVAD) greater than 20 degrees is highly likely to progress (Phase 2 curve). The standard early management for progressive infantile curves is serial corrective casting (Mehta casting) to harness growth and correct the deformity.
Question 5094
Topic: Thoracolumbar Spine & Deformity
A 14-year-old gymnast presents with chronic lower back pain and severe hamstring tightness. Radiographs reveal an L5-S1 isthmic spondylolisthesis with 60% anterior translation of L5 on S1 (Grade III). Nonoperative management has failed over 6 months. What is the most appropriate surgical intervention?
Correct Answer & Explanation
. L4-S1 posterolateral fusion in situ
Explanation
For high-grade (Grade III or higher) isthmic spondylolisthesis in children, an L4-S1 fusion spanning the slip and the adjacent segment is recommended to prevent progression and reduce the high risk of pseudarthrosis. In situ posterolateral fusion is safe and has an excellent track record compared to aggressive reduction.
Question 5095
Topic: 6. Spine
A 2-year-old boy with achondroplasia presents with a history of recurrent apneic episodes, delayed motor milestones, and hyperreflexia in the bilateral lower extremities. Which of the following is the most likely etiology?
Correct Answer & Explanation
. Foramen magnum stenosis
Explanation
Infants and young children with achondroplasia are at risk for foramen magnum stenosis, which can cause cervicomedullary compression. Symptoms include central apnea, hyperreflexia, and hypotonia, warranting emergent MRI and potential surgical decompression.
Question 5096
Topic: 6. Spine
A 14-year-old gymnast presents with severe back pain and radiculopathy. Radiographs show an L5-S1 isthmic spondylolisthesis with a 65% slip (Meyerding Grade 3). If a surgical reduction of the slip is attempted, which nerve root is at the highest risk for iatrogenic injury?
Correct Answer & Explanation
. L5
Explanation
In high-grade spondylolisthesis at L5-S1, attempting to surgically reduce the L5 vertebra back onto the S1 sacral dome places the L5 nerve root under significant tension, posing a high risk for stretch injury or palsy.
Question 5097
Topic: Thoracolumbar Spine & Deformity
A 14-year-old female presents with severe back pain and radiating bilateral leg pain. Radiographs reveal an L5-S1 isthmic spondylolisthesis with an 80% slip (Meyerding Grade IV) and a high slip angle. She has failed conservative management. What is the recommended surgical approach?
Correct Answer & Explanation
. L4-S1 posterior decompression and instrumented fusion
Explanation
High-grade spondylolisthesis (>50% slip) with radicular symptoms and failure of conservative management is best treated with posterior decompression and instrumented fusion. Pars repair is reserved for low-grade slips without nerve root compression.
Question 5098
Topic: 6. Spine
A 65-year-old man with advanced ankylosing spondylitis and a totally fused lumbar spine is undergoing a THA.
Due to his spinopelvic stiffness, how does his pelvic mobility alter his risk of impingement and dislocation when transitioning from a standing to a sitting position?
Correct Answer & Explanation
. The pelvis fails to tilt posteriorly, increasing the risk of anterior femoroacetabular impingement and posterior dislocation.
Explanation
In a normal spinopelvic relationship, sitting induces posterior pelvic tilt, which functionally increases acetabular anteversion and clears the anterior neck. A stiff spine prevents this posterior tilt, leading to anterior impingement during flexion and subsequent posterior levering out of the femoral head.
Question 5099
Topic: 6. Spine
A 65-year-old man undergoes THA. Preoperative radiographs show severe lumbar spine ankylosis with a fixed anterior pelvic tilt (hyperlordosis). To prevent posterior dislocation when the patient transitions from standing to sitting, how should the acetabular component be positioned compared to a patient with a normal, mobile spine?
Correct Answer & Explanation
. Increase acetabular anteversion
Explanation
A stiff spine with a fixed anterior pelvic tilt fails to accommodate hip flexion by tilting posteriorly during sitting. Increasing the cup anteversion compensates for this lack of dynamic clearance, reducing anterior impingement and posterior dislocation risk.
Question 5100
Topic: 6. Spine
A 68-year-old woman with a history of multilevel lumbar spinal fusion (L2-pelvis) undergoes a primary total hip arthroplasty (THA). Which of the following component positioning strategies is most appropriate to minimize her risk of posterior dislocation?
Correct Answer & Explanation
. Increased acetabular anteversion
Explanation
Patients with lumbosacral fusions extending to the pelvis have a stiff spinopelvic junction. They lose the ability to increase pelvic tilt (posteriorly) when sitting. Normally, posterior pelvic tilt increases functional acetabular anteversion, protecting against posterior dislocation during hip flexion. In a fused spine, this compensatory mechanism is lost, requiring the surgeon to place the cup in increased anteversion and inclination to accommodate the seated position and prevent posterior impingement and subsequent dislocation.
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