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Thoracolumbar Spine & Deformity MCQs

Practice Set 43 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 841

Topic: Thoracolumbar Spine & Deformity

A 15-year-old female gymnast complains of chronic lower back pain and tightness in her hamstrings. Imaging reveals a Meyerding Grade II isthmic spondylolisthesis at L5-S1. Despite 6 months of dedicated physical therapy, bracing, and activity modification, her symptoms severely limit her daily activities. What is the most appropriate surgical intervention?

. L5 pars interarticularis repair (Buck's repair)
. L4-L5 posterior spinal fusion
. L5-S1 posterior instrumented fusion
. Laminectomy of L5 without fusion
. Anterior lumbar interbody fusion at L4-L5

Correct Answer & Explanation

. L5 pars interarticularis repair (Buck's repair)

Explanation

For a symptomatic Grade II isthmic spondylolisthesis at L5-S1 that fails conservative management, L5-S1 posterior instrumented fusion is the gold standard treatment. Pars repair (Buck's repair) is typically reserved for young patients with a pars defect but no significant slip (Grade 0 or early Grade I) at levels above L5-S1. Laminectomy alone in a pediatric patient with an unstable slip is contraindicated.

Question 842

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male falls from a ladder and sustains localized thoracolumbar pain. He is neurologically intact. CT and MRI confirm an L1 burst fracture with 15 degrees of kyphosis, 30% canal compromise, and an intact posterior ligamentous complex.

Based on the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

. Urgent surgical decompression
. Posterior spinal fusion without decompression
. Thoracolumbosacral orthosis (TLSO)
. Anterior corpectomy and plating
. Short-segment percutaneous pedicle screw fixation

Correct Answer & Explanation

. Urgent surgical decompression

Explanation

The patient's TLICS score is 2 (Burst fracture = 2, Neurologically intact = 0, PLC intact = 0). A score of 3 or less indicates non-operative management, typically with a TLSO.

Question 843

Topic: Thoracolumbar Spine & Deformity

A 12-year-old gymnast presents with persistent lower back pain. Radiographs reveal a Grade II isthmic spondylolisthesis at L5-S1. She is neurologically intact. After failing 6 months of dedicated physical therapy, bracing, and activity modification, her back pain remains disabling. What is the most appropriate surgical treatment?

. L5-S1 anterior lumbar interbody fusion
. L5 laminectomy and Gill procedure without fusion
. L5-S1 in situ posterolateral fusion
. L5-S1 posterior instrumentation and reduction of the slip to Grade 0
. L4-S1 posterior spinal fusion

Correct Answer & Explanation

. L5-S1 anterior lumbar interbody fusion

Explanation

For pediatric patients with symptomatic low-grade (Grade I or II) isthmic spondylolisthesis that fails conservative management, the standard surgical treatment is an L5-S1 in situ posterolateral fusion. Decompression (Gill procedure) alone is contraindicated in children as it increases instability and slip progression. Reduction of low-grade slips is unnecessary and carries a high risk of L5 nerve root injury without added clinical benefit.

Question 844

Topic: Thoracolumbar Spine & Deformity
A 13-year-old gymnast complains of refractory lower back pain. Radiographs reveal an isthmic spondylolisthesis at L5-S1 with a 60% slip (Meyerding Grade III). Which surgical option is most appropriate if conservative management fails?
. Pars interarticularis repair (Buck's repair)
. In situ posterolateral fusion from L5 to S1
. Laminectomy alone without fusion
. Instrumented posterolateral and interbody fusion of L5-S1
. Anterior lumbar interbody fusion without posterior instrumentation

Correct Answer & Explanation

. Instrumented posterolateral and interbody fusion of L5-S1

Explanation

A high-grade slip (>50%) in an actively growing adolescent is highly unstable and poses a significant risk for progression. Surgical management typically requires instrumented stabilization and fusion (posterolateral with or without interbody fusion) to halt progression and alleviate symptoms.

Question 845

Topic: Thoracolumbar Spine & Deformity
A 14-year-old competitive gymnast presents with persistent lower back pain that radiates into her bilateral buttocks. Radiographs reveal a bilateral pars interarticularis defect at L5-S1 with 60% anterior translation of the L5 vertebral body upon the sacrum. According to the Meyerding classification, what grade is this slip, and what is the current accepted standard definitive surgical management if conservative treatment has failed?
. Grade II; direct pars interarticularis repair (e.g., Buck's or Scott wiring)
. Grade III; L5-S1 in situ posterolateral or interbody fusion with instrumentation
. Grade III; L4-S1 long-segment posterolateral fusion without decompression
. Grade IV; aggressive L5-S1 anatomic reduction and circumferential fusion
. Grade IV; L5 corpectomy with strut grafting

Correct Answer & Explanation

. Grade III; L5-S1 in situ posterolateral or interbody fusion with instrumentation

Explanation

The Meyerding classification grades spondylolisthesis based on the percentage of anterior translation: Grade I (0-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (spondyloptosis, >100%). A 60% slip is a Grade III (High-Grade) isthmic spondylolisthesis. While low-grade slips in young athletes can sometimes be treated with direct pars repair if symptomatic despite conservative care, high-grade slips (>50%) have a much higher risk of progression, pseudoarthrosis, and neurologic deficit. The accepted standard of care for a symptomatic high-grade slip is L5-S1 fusion (in situ or with partial reduction depending on the surgeon and sagittal balance parameters), frequently incorporating interbody support and decompression if radicular symptoms are present.

Question 846

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male sustains an L1 burst fracture in a motor vehicle collision. He presents with normal neurologic status (ASIA E). A subsequent MRI confirms that the posterior ligamentous complex is completely intact. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his score and the appropriate treatment recommendation?

. Score 1, conservative management
. Score 2, conservative management
. Score 4, operative management
. Score 5, operative management
. Score 7, operative management

Correct Answer & Explanation

. Score 1, conservative management

Explanation

The TLICS score assigns points based on morphology, neurological status, and PLC integrity. Morphology: Burst = 2 points. Neurological status: Intact = 0 points. PLC: Intact = 0 points. Total score = 2. A score of 3 or less is typically treated non-operatively with bracing or observation.

Question 847

Topic: Thoracolumbar Spine & Deformity

A 30-year-old male is diagnosed with an L1 burst fracture after a fall. He is neurologically intact, and MRI confirms an intact posterior ligamentous complex. His TLICS score is 2. What is the most appropriate management?

. Anterior corpectomy and fusion
. Posterior pedicle screw fixation one level above and below
. Thoracolumbosacral orthosis (TLSO) brace
. Laminectomy and facet fusion
. Percutaneous vertebroplasty

Correct Answer & Explanation

. Anterior corpectomy and fusion

Explanation

A Thoracolumbar Injury Classification and Severity (TLICS) score of 3 or less indicates non-operative management. For an isolated burst fracture with intact neurology and posterior ligaments, a TLSO brace is the standard of care.

Question 848

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female gymnast presents with progressive lower back pain. Radiographs demonstrate an isthmic spondylolisthesis at L5-S1 with 60% anterior translation of L5 on S1. According to the Meyerding classification, what grade is this slip, and what is the generally recommended definitive surgical management?
. Grade II; TLSO bracing
. Grade III; pars interarticularis repair (Buck's procedure)
. Grade III; L5-S1 fusion
. Grade IV; TLSO bracing
. Grade IV; L5-S1 fusion

Correct Answer & Explanation

. Grade III; L5-S1 fusion

Explanation

The Meyerding classification grades the degree of anterior translation: Grade I (0-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (>100% or spondyloptosis). A 60% slip is Grade III. High-grade slips (III, IV, V) in symptomatic adolescents are generally unstable and require stabilization via fusion (usually L5-S1 or L4-S1 with instrumentation). Pars repairs (e.g., Buck's, Scott wiring) are reserved for symptomatic Grade I slips or spondylolysis without significant slip.

Question 849

Topic: Thoracolumbar Spine & Deformity
A 15-year-old female gymnast presents with insidious onset of mechanical low back pain. Standing lateral radiographs reveal a Grade 2 L5-S1 spondylolisthesis. According to the Wiltse classification of spondylolisthesis, this patient most likely has a Type II slip. What is the primary underlying anatomic pathomechanism for a Wiltse Type II spondylolisthesis?
. Congenital dysplasia of the L5-S1 facet joints
. A defect or stress fracture in the pars interarticularis
. Degenerative arthrosis of the facet joints and intervertebral disc
. An acute traumatic fracture of the pedicle or lamina
. Destruction of the posterior elements by a primary bone tumor

Correct Answer & Explanation

. A defect or stress fracture in the pars interarticularis

Explanation

The Wiltse classification categorizes spondylolisthesis by etiology. Type I is Dysplastic (congenital abnormalities of the upper sacrum or L5 arch). Type II is Isthmic, caused by a defect (often a stress fracture from repetitive hyperextension, classic in gymnasts) in the pars interarticularis. Type III is Degenerative (older adults, intact pars). Type IV is Traumatic (acute fracture of the bony hook other than the pars). Type V is Pathologic (tumor/infection).

Question 850

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with an insidious onset of low back pain exacerbated by extension. Radiographs reveal a Grade I isthmic spondylolisthesis at L5-S1. The bilateral pars interarticularis defects are most clearly visualized on which specific radiographic view?

. Anteroposterior (AP)
. Cross-table lateral
. Oblique
. Flexion-extension lateral
. Ferguson view

Correct Answer & Explanation

. Anteroposterior (AP)

Explanation

The oblique radiograph of the lumbar spine is the classic view to best visualize the pars interarticularis, often described by the 'Scotty dog' sign. A defect or fracture of the pars interarticularis (spondylolysis) appears as a radiolucent line at the 'collar' of the Scotty dog.

Question 851

Topic: Thoracolumbar Spine & Deformity
Based on the Meyerding classification for spondylolisthesis, a Grade III slip indicates what percentage of anterior translation of the superior vertebral body over the inferior vertebral body?
. 1-25%
. 26-50%
. 51-75%
. 76-100%
. >100%

Correct Answer & Explanation

. 51-75%

Explanation

The Meyerding classification grades the severity of spondylolisthesis based on the percentage of slippage: Grade I (1-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (spondyloptosis, >100%).

Question 852

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with insidious onset of low back pain exacerbated by extension. Plain radiographs are normal. An MRI shows marrow edema in the pars interarticularis of L5 bilaterally without a definitive fracture line. What is the most appropriate initial management?

. Immediate pars repair with pedicle screws and laminar hooks
. Rigid TLSO brace for 3 months with immediate return to competitive sports
. Restriction of sports/extension activities and physical therapy focused on core strengthening
. Epidural steroid injections
. L5-S1 anterior lumbar interbody fusion (ALIF)

Correct Answer & Explanation

. Immediate pars repair with pedicle screws and laminar hooks

Explanation

The patient has an acute stress reaction of the pars interarticularis (early spondylolysis), evidenced by MRI marrow edema without a radiographic defect. The mainstay of treatment is conservative: cessation of the offending activity (extension loading), rest, and physical therapy focused on antilordotic core strengthening. Surgery is not indicated for early stress reactions.

Question 853

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast is diagnosed with a L5 isthmic spondylolysis. Which of the following factors is the strongest risk factor for the progression of spondylolysis to spondylolisthesis?

. Low pelvic incidence
. High slip angle
. Sacral sparing on MRI
. Absence of spina bifida occulta
. Female sex with isolated L4 defect

Correct Answer & Explanation

. Low pelvic incidence

Explanation

Risk factors for the progression of spondylolysis to spondylolisthesis include a high slip angle, high pelvic incidence, dysplastic facet joints, and dome-shaped sacrum. The highest risk of progression occurs during the adolescent growth spurt.

Question 854

Topic: Thoracolumbar Spine & Deformity

A 22-year-old male falls from a roof and sustains an L1 vertebral fracture. Neurological examination is completely normal. CT and MRI show an L1 burst fracture with 15 degrees of kyphosis, retropulsion of the posterosuperior body fragment by 2 mm, and an intact posterior ligamentous complex. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

. Thoracolumbosacral orthosis (TLSO) bracing and early mobilization
. Short-segment posterior instrumented fusion
. Anterior corpectomy and strut grafting
. Long-segment posterior instrumented fusion
. Percutaneous vertebroplasty

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing and early mobilization

Explanation

The TLICS score for this patient is calculated as follows: Morphology is Burst (2 points); Neurologic status is Intact (0 points); Posterior Ligamentous Complex (PLC) is Intact (0 points). The total TLICS score is 2. A score of 3 or less indicates non-operative management, typically with TLSO bracing. A score of 4 is indeterminate, and 5 or more dictates operative intervention.

Question 855

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with refractory lower back pain. Radiographs reveal a Grade II isthmic spondylolisthesis at L5-S1. Her pelvic parameters are measured. Which of the following statements correctly describes the relationship between pelvic incidence (PI) and isthmic spondylolisthesis?

. High PI correlates with a higher risk of spondylolisthesis and slip progression
. Low PI correlates with a higher risk of spondylolisthesis and slip progression
. High PI is protective against the development of pars interarticularis defects
. PI decreases significantly as a patient progresses from adolescence to adulthood
. There is no established correlation between pelvic incidence and isthmic spondylolisthesis

Correct Answer & Explanation

. High PI correlates with a higher risk of spondylolisthesis and slip progression

Explanation

Pelvic incidence (PI) is an anatomical parameter that is constant in an adult. High pelvic incidence results in a steeper sacral slope and higher shear forces at the lumbosacral junction. It is strongly correlated with both the development and progression of isthmic spondylolisthesis at L5-S1.

Question 856

Topic: Thoracolumbar Spine & Deformity

An adult patient is undergoing planning for complex corrective surgery to address severe symptomatic degenerative lumbar scoliosis and sagittal imbalance. Measurement of the patient's pelvic incidence (PI) yields a value of 55 degrees. To achieve optimal post-operative global sagittal balance, what is the approximate target value for the post-operative lumbar lordosis (LL)?

. 25 degrees
. 35 degrees
. 45 degrees
. 55 degrees
. 75 degrees

Correct Answer & Explanation

. 45 degrees

Explanation

In the sagittal plane, a harmonious spinopelvic relationship is achieved when the lumbar lordosis (LL) roughly matches the pelvic incidence (PI). The widely accepted formula proposed by Schwab and the SRS-Schwab adult spinal deformity classification states that the target PI minus LL (PI-LL mismatch) should be within 9-10 degrees (ideally < 10 degrees). Therefore, if PI is 55 degrees, the target LL should be approximately 55 degrees.

Question 857

Topic: Thoracolumbar Spine & Deformity

A 30-year-old male sustains a T12 burst fracture after a fall. On examination, he is neurologically intact. MRI demonstrates definitive disruption of the posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the recommended management?

. Score 2; Non-operative management
. Score 4; Surgeon's choice of operative or non-operative management
. Score 5; Operative management
. Score 7; Operative management
. Score 8; Non-operative management

Correct Answer & Explanation

. Score 5; Operative management

Explanation

The TLICS system evaluates three categories: morphology, neurologic status, and posterior ligamentous complex (PLC) integrity. This patient has a burst fracture morphology (2 points), intact neurologic status (0 points), and a definitively disrupted PLC (3 points). Total score = 2 + 0 + 3 = 5. A TLICS score <= 3 suggests non-operative management, a score of 4 is indeterminate (surgeon's choice), and a score >= 5 is a strong indication for surgical management.

Question 858

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female presents with severe mechanical lower back pain and a 'waddling' gait. Radiographs reveal a Meyerding Grade IV isthmic spondylolisthesis at L5-S1. The slip angle is measured at 55 degrees. What is the most critical pelvic parameter that determines the overall sagittal balance and risk of progression in this patient?
. Sacral Slope
. Pelvic Tilt
. Pelvic Incidence
. Lumbar Lordosis
. Sagittal Vertical Axis

Correct Answer & Explanation

. Pelvic Incidence

Explanation

Pelvic Incidence (PI) is a fixed morphological parameter unique to each individual and is defined as the sum of Pelvic Tilt (PT) and Sacral Slope (SS) (PI = PT + SS). In high-grade spondylolisthesis (Meyerding Grade III-V), patients typically have a high Pelvic Incidence, which predisposes them to greater shear forces at the lumbosacral junction. A high slip angle (>45-50 degrees) combined with high PI strongly correlates with an increased risk of further progression and poor functional outcomes, often necessitating surgical reduction and stabilization.

Question 859

Topic: Thoracolumbar Spine & Deformity
In the evaluation of adult spinal deformity, which of the following radiographic parameters has been most strongly and consistently correlated with poor Health-Related Quality of Life (HRQOL) scores?
. A coronal Cobb angle greater than 30 degrees
. A pelvic incidence to lumbar lordosis (PI-LL) mismatch of less than 10 degrees
. A Sagittal Vertical Axis (SVA) greater than 50 mm
. A thoracic kyphosis greater than 40 degrees
. An apical vertebral rotation of Grade III

Correct Answer & Explanation

. A Sagittal Vertical Axis (SVA) greater than 50 mm

Explanation

In adult spinal deformity, sagittal plane alignment is the primary driver of clinical symptoms and poor Health-Related Quality of Life (HRQOL) scores. A positive Sagittal Vertical Axis (SVA) > 50 mm (measured as the horizontal distance from a plumb line dropped from the center of the C7 vertebral body to the posterior superior corner of the S1 endplate) correlates strongly with increased pain and decreased function. While a PI-LL mismatch > 10 degrees is also a crucial predictor, the option provided incorrectly stated 'less than 10 degrees'.

Question 860

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male is evaluated after a fall from a ladder. CT imaging demonstrates an L1 burst fracture with 15 degrees of kyphosis and 30% canal compromise. The posterior ligamentous complex (PLC) is completely intact on MRI. Neurologic examination is entirely normal. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

. Thoracolumbosacral orthosis (TLSO) and early mobilization
. Short-segment posterior pedicle screw fixation
. Anterior L1 corpectomy and strut grafting
. L1 laminectomy without fusion
. Long-segment posterior fusion

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) and early mobilization

Explanation

This patient has a TLICS score of 2 (Morphology: Burst = 2; Neuro: Intact = 0; PLC: Intact = 0). A score of less than 4 indicates non-operative management, making a TLSO brace or early mobilization the most appropriate choice.

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