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Thoracolumbar Spine & Deformity MCQs

Practice Set 25 of 49

This practice set contains high-yield board review questions covering key concepts in Thoracolumbar Spine & Deformity. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 481

Topic: Thoracolumbar Spine & Deformity

A 19-year-old female sustains a bony Chance fracture of L2 due to a lap-belt injury during a high-speed collision. Which of the following associated injuries is most commonly found in this patient population?

. Aortic transection
. Gastrointestinal hollow viscus injury
. Renal artery avulsion
. Diaphragmatic rupture
. Splenic laceration

Correct Answer & Explanation

. Gastrointestinal hollow viscus injury

Explanation

Chance fractures are flexion-distraction injuries highly associated with lap-belt use. Up to 50% of patients with these fractures have concomitant intra-abdominal injuries, most commonly involving hollow viscous organs like the small bowel.

Question 482

Topic: Thoracolumbar Spine & Deformity

When planning a long spinal fusion for adult degenerative scoliosis to restore sagittal balance, which fixed anatomical parameter is most critical for calculating the patient's target lumbar lordosis?

. Sacral slope
. Pelvic tilt
. Pelvic incidence
. Thoracic kyphosis
. Sagittal vertical axis

Correct Answer & Explanation

. Pelvic incidence

Explanation

Pelvic incidence (PI) is a fixed morphological parameter unique to each individual. Restoring lumbar lordosis to match the PI (ideally within 9 degrees) is the critical target for achieving optimal sagittal balance in deformity surgery.

Question 483

Topic: Thoracolumbar Spine & Deformity

A 16-year-old gymnast presents with chronic low back pain exacerbated by extension. Lateral radiographs demonstrate a grade I spondylolisthesis at L5-S1. What is the most likely underlying anatomic defect?

. Degenerative facet arthropathy
. Pedicle stress fracture
. Pars interarticularis defect
. Congenital dysplasia of the sacrum
. Ligamentum flavum hypertrophy

Correct Answer & Explanation

. Pars interarticularis defect

Explanation

Isthmic spondylolisthesis in adolescent athletes (especially those doing repetitive extension) is caused by a stress fracture or defect of the pars interarticularis (spondylolysis).

Question 484

Topic: Thoracolumbar Spine & Deformity

Which of the following represents the classic Sorensen radiographic criteria for diagnosing Scheuermann's kyphosis?

. Anterior wedging of >5 degrees in at least 3 consecutive vertebrae
. Anterior wedging of >10 degrees in at least 2 consecutive vertebrae
. Schmorl's nodes in at least 4 non-consecutive vertebrae
. Thoracic kyphosis >45 degrees with uniform disc space narrowing
. Apophyseal ring fractures at multiple levels

Correct Answer & Explanation

. Anterior wedging of >5 degrees in at least 3 consecutive vertebrae

Explanation

The classic Sorensen criteria require the presence of anterior vertebral wedging of greater than 5 degrees in at least three consecutive vertebrae to diagnose Scheuermann's kyphosis.

Question 485

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with persistent low back pain unresponsive to 6 months of conservative management. Radiographs reveal a Grade II L5-S1 isthmic spondylolisthesis. What is the most appropriate surgical management?

. L5-S1 anterior lumbar interbody fusion (ALIF) alone
. L5 pars defect repair with pedicle screws and laminar hooks
. In situ L5-S1 posterolateral instrumented fusion
. L5-S1 total disc replacement
. Sacral dome osteotomy

Correct Answer & Explanation

. In situ L5-S1 posterolateral instrumented fusion

Explanation

In adolescents with symptomatic low-grade isthmic spondylolisthesis failing conservative care, in situ posterolateral instrumented fusion of L5-S1 is the standard of care. Pars repairs are typically reserved for L1-L4 defects without a significant slip.

Question 486

Topic: Thoracolumbar Spine & Deformity

Which of the following radiographic parameters defines an adequate restoration of sagittal balance following adult spinal deformity corrective surgery?

. Pelvic incidence minus Lumbar lordosis (PI-LL) less than 10 degrees
. Sagittal vertical axis (SVA) greater than 10 cm
. Pelvic tilt (PT) greater than 25 degrees
. Thoracic kyphosis greater than lumbar lordosis
. Sacral slope (SS) equal to zero

Correct Answer & Explanation

. Pelvic incidence minus Lumbar lordosis (PI-LL) less than 10 degrees

Explanation

Adequate sagittal alignment in adult spinal deformity is widely defined by a PI-LL mismatch of less than 10 degrees, an SVA less than 5 cm, and a PT less than 20 degrees. Proper restoration of these parameters improves health-related quality of life outcomes.

Question 487

Topic: Thoracolumbar Spine & Deformity

A 65-year-old woman presents with worsening low back pain and a progressive forward-leaning posture while walking. Radiographs demonstrate degenerative lumbar scoliosis. Her measured pelvic incidence (PI) is 60 degrees. To achieve optimal sagittal balance postoperatively, what should her lumbar lordosis (LL) ideally be reconstructed to?

. 20 degrees
. 35 degrees
. 45 degrees
. 60 degrees
. 80 degrees

Correct Answer & Explanation

. 60 degrees

Explanation

Optimal sagittal balance in adult spinal deformity requires the lumbar lordosis (LL) to be matched within 10 degrees of the patient's pelvic incidence (PI). Therefore, for a PI of 60 degrees, the ideal LL should be approximately 60 degrees (acceptable range 50 to 70 degrees).

Question 488

Topic: Thoracolumbar Spine & Deformity

In the Thoracolumbar Injury Classification and Severity (TLICS) system, which of the following morphological patterns is assigned the highest point value?

. Compression
. Burst
. Translation/Rotation
. Distraction
. Flexion-distraction without ligamentous injury

Correct Answer & Explanation

. Distraction

Explanation

The TLICS system assigns 4 points to a distraction morphology, which is the highest score in the morphology category. Translation/rotation receives 3 points, burst 2, and compression 1.

Question 489

Topic: Thoracolumbar Spine & Deformity

In the evaluation of adult spinal deformity, Pelvic Incidence (PI) is a fixed morphologic parameter. What is the anatomic formula relating Pelvic Incidence (PI), Pelvic Tilt (PT), and Sacral Slope (SS)?

. PI = PT + SS
. PI = PT - SS
. PI = SS - PT
. PT = PI + SS
. SS = PI + PT

Correct Answer & Explanation

. PI = PT + SS

Explanation

Pelvic Incidence is a fixed anatomical parameter defined as the sum of Pelvic Tilt and Sacral Slope (PI = PT + SS). It dictates the required lumbar lordosis for optimal sagittal balance.

Question 490

Topic: Thoracolumbar Spine & Deformity

What is the most common anatomic level for an isthmic spondylolisthesis, and which patient population most frequently presents with symptoms?

. L4-L5; elderly females
. L5-S1; adolescent athletes
. L3-L4; middle-aged males
. L5-S1; elderly females
. L4-L5; adolescent athletes

Correct Answer & Explanation

. L5-S1; adolescent athletes

Explanation

Isthmic spondylolisthesis most commonly occurs at the L5-S1 level due to a pars interarticularis defect. It classically presents symptomatically in adolescent athletes subjected to repetitive hyperextension (e.g., gymnasts).

Question 491

Topic: Thoracolumbar Spine & Deformity

A 68-year-old female presents with neurogenic claudication. Imaging reveals an L4-L5 degenerative spondylolisthesis. Which of the following anatomic or radiographic findings is most strongly associated with the development of this condition?

. Coronal orientation of the facet joints
. Sagittal orientation of the facet joints
. Decreased pelvic incidence
. Pars interarticularis defect
. Increased lumbar lordosis

Correct Answer & Explanation

. Sagittal orientation of the facet joints

Explanation

Degenerative spondylolisthesis at L4-L5 is highly associated with sagittal orientation of the facet joints (>45 degrees relative to the coronal plane), which allows forward slippage of the vertebra. Pars defects cause isthmic, not degenerative, spondylolisthesis.

Question 492

Topic: Thoracolumbar Spine & Deformity

A 32-year-old male falls 10 feet, sustaining an L1 burst fracture. He is neurologically intact (ASIA E). A non-contrast MRI confirms that the posterior ligamentous complex (PLC) is completely intact. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the patient's score and the recommended management?

. Score 2, nonoperative management
. Score 4, operative management
. Score 4, nonoperative management
. Score 5, operative management
. Score 7, operative management

Correct Answer & Explanation

. Score 2, nonoperative management

Explanation

The TLICS score is calculated as follows: Burst fracture morphology = 2 points, Neurologically intact = 0 points, Intact PLC = 0 points. A total score of 2 indicates that nonoperative management (such as bracing) is recommended.

Question 493

Topic: Thoracolumbar Spine & Deformity

A 9-month-old boy is referred for a 25-degree left thoracic scoliosis.

Radiographs demonstrate a rib-vertebral angle difference (RVAD) of 25 degrees. What is the most likely natural history and appropriate treatment?

. Likely to resolve spontaneously; observation only
. Likely to resolve spontaneously; nighttime bracing
. High risk of progression; serial Mehta casting
. High risk of progression; immediate growth-friendly instrumentation
. Requires immediate MRI to rule out syringomyelia before intervention

Correct Answer & Explanation

. High risk of progression; serial Mehta casting

Explanation

This is infantile idiopathic scoliosis. According to Mehta's criteria, an RVAD greater than 20 degrees indicates a high likelihood of curve progression. The gold standard for progressive infantile curves is early serial derotational casting.

Question 494

Topic: Thoracolumbar Spine & Deformity

In a young child with early-onset scoliosis and multiple fused ribs, vertical expandable prosthetic titanium rib (VEPTR) surgery is indicated primarily to treat or prevent which condition?

. Cor pulmonale
. Thoracic insufficiency syndrome
. Aortic root dilation
. Progression of pelvic obliquity
. Superior mesenteric artery syndrome

Correct Answer & Explanation

. Thoracic insufficiency syndrome

Explanation

VEPTR devices are primarily used in early-onset scoliosis with associated rib fusions to expand the constrained hemithorax. This expansion treats or prevents thoracic insufficiency syndrome, allowing for more normal lung development and volume.

Question 495

Topic: Thoracolumbar Spine & Deformity
A 15-year-old gymnast presents with persistent low back pain and tight hamstrings. Radiographs reveal a Grade III isthmic spondylolisthesis at L5-S1. She has failed 6 months of nonoperative treatment. What is the most appropriate surgical intervention?
. Pars interarticularis repair (Buck's procedure)
. L5-S1 anterior lumbar interbody fusion without posterior fixation
. L5-S1 posterior instrumented fusion
. Laminectomy without fusion
. T10 to pelvis posterior fusion

Correct Answer & Explanation

. L5-S1 posterior instrumented fusion

Explanation

For high-grade (Grade III or higher) isthmic spondylolisthesis failing conservative care, an instrumented posterior spinal fusion (with or without interbody support) is indicated. Pars repair is reserved for young patients with normal alignment and no slip.

Question 496

Topic: Thoracolumbar Spine & Deformity

A 15-year-old male gymnast complains of worsening lower back pain over the past 3 weeks, exacerbated by extension. Plain radiographs show no obvious cortical break or spondylolisthesis. Which imaging modality is most sensitive for detecting an early, active pars interarticularis stress reaction?

. Non-contrast CT scan of the lumbar spine
. T2-weighted STIR or fat-suppressed MRI
. Standing lateral flexion-extension radiographs
. Technetium-99m single-photon emission CT (SPECT) scan
. Ultrasound of the lumbar paraspinal muscles

Correct Answer & Explanation

. T2-weighted STIR or fat-suppressed MRI

Explanation

MRI with T2 fat-suppressed or STIR sequences is highly sensitive for detecting bone marrow edema indicative of an early pars stress reaction before a definitive fracture occurs, successfully avoiding the ionizing radiation associated with CT or SPECT scans.

Question 497

Topic: Thoracolumbar Spine & Deformity

An 8-month-old boy is diagnosed with infantile idiopathic scoliosis. Radiographs reveal a 25-degree left thoracic curve. Which of the following radiographic parameters best predicts whether this curve will progress rather than spontaneously resolve?

. Risser sign progression
. Cobb angle magnitude at presentation alone
. Rib-vertebral angle difference (RVAD) greater than 20 degrees
. Nash-Moe rotation of grade 1
. Apical vertebral translation greater than 1 cm

Correct Answer & Explanation

. Rib-vertebral angle difference (RVAD) greater than 20 degrees

Explanation

Mehta's rib-vertebral angle difference (RVAD) is the most reliable prognostic indicator for infantile idiopathic scoliosis. An RVAD greater than 20 degrees strongly predicts progressive deformity requiring intervention, whereas an RVAD less than 20 degrees often resolves spontaneously.

Question 498

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female presents with back pain and is diagnosed with an L5-S1 isthmic spondylolisthesis. Which of the following radiographic findings is considered the most significant risk factor for further slip progression?

. A slip angle greater than 50 degrees
. A Meyerding Grade I slip
. The presence of spina bifida occulta
. Lumbar hyperlordosis greater than 40 degrees
. Sacral agenesis

Correct Answer & Explanation

. A slip angle greater than 50 degrees

Explanation

The slip angle (sagittal roll) is the angle between the L5 inferior endplate and the posterior aspect of the S1 body. A slip angle greater than 40-50 degrees is the most significant predictor of slip progression in spondylolisthesis and often dictates the need for surgical stabilization.

Question 499

Topic: Thoracolumbar Spine & Deformity

A 15-year-old male gymnast complains of chronic lower back pain exacerbated by extension. Radiographs show a grade II isthmic spondylolisthesis at L5-S1. He has failed 6 months of physical therapy and bracing, and his hamstring tightness is worsening. What is the recommended surgical management?

. L5-S1 laminectomy without fusion
. Pars interarticularis repair with screw fixation
. In situ posterolateral L5-S1 fusion
. L4-L5-S1 posterior instrumented fusion
. Anterior lumbar interbody fusion (ALIF) at L4-L5

Correct Answer & Explanation

. In situ posterolateral L5-S1 fusion

Explanation

For a symptomatic low-grade (Grade I or II) isthmic spondylolisthesis failing conservative management, an in situ posterolateral fusion of L5-S1 (with or without instrumentation) is the standard surgical treatment. Pars repair is generally reserved for isolated spondylolysis without slip or very early slips in younger patients.

Question 500

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast presents with persistent low back pain exacerbated by extension. Imaging reveals an acute, unilateral pars interarticularis stress fracture at L5 without spondylolisthesis. What is the most appropriate initial treatment?

. L5-S1 posterolateral fusion
. Pars interarticularis repair
. Thoracolumbosacral orthosis (TLSO) and activity modification
. Epidural steroid injections
. Immediate return to play with aggressive physical therapy

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) and activity modification

Explanation

The initial treatment for an acute spondylolysis (pars stress fracture) without slip is conservative. This typically consists of activity restriction and bracing (such as a TLSO or Boston brace) to limit extension and allow for bony healing.

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