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Thoracolumbar Spine & Deformity MCQs

Practice Set 35 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 681

Topic: Thoracolumbar Spine & Deformity

A 65-year-old female presents with severe mechanical lower back pain, early satiety, and a flexed posture. Radiographs reveal a severe degenerative flatback deformity. Her measured pelvic incidence (PI) is 58 degrees. To achieve optimal spinopelvic alignment and clinical outcomes postoperatively, what should her target lumbar lordosis (LL) ideally be?

. 20 degrees
. 38 degrees
. 58 degrees
. 78 degrees
. 90 degrees

Correct Answer & Explanation

. 58 degrees

Explanation

In the surgical correction of adult spinal deformity, achieving appropriate spinopelvic alignment is critical for good functional outcomes. A key principle (Schwab criteria) is that the postoperative lumbar lordosis (LL) should match the patient's fixed pelvic incidence (PI) within 9 degrees (LL = PI ± 9°). Therefore, for a PI of 58 degrees, a target LL of approximately 58 degrees is ideal to minimize the pelvic tilt and restore upright sagittal balance.

Question 682

Topic: Thoracolumbar Spine & Deformity

A 65-year-old woman presents with progressive low back pain and difficulty standing upright. Standing full-length lateral spine radiographs reveal a Pelvic Incidence (PI) of 60 degrees and a Pelvic Tilt (PT) of 35 degrees. What is her Sacral Slope (SS), and what does this PT value indicate about her compensatory mechanism?

. SS is 25 degrees; indicates pelvic retroversion to compensate for sagittal malalignment.
. SS is 95 degrees; indicates pelvic anteversion to compensate for sagittal malalignment.
. SS is 25 degrees; indicates pelvic anteversion to compensate for coronal malalignment.
. SS is 95 degrees; indicates pelvic retroversion to compensate for coronal malalignment.
. SS is 35 degrees; indicates normal sagittal alignment.

Correct Answer & Explanation

. SS is 25 degrees; indicates pelvic retroversion to compensate for sagittal malalignment.

Explanation

The morphological parameter Pelvic Incidence (PI) is a fixed anatomical parameter and is the sum of Pelvic Tilt (PT) and Sacral Slope (SS) (PI = PT + SS). Therefore, SS = PI - PT = 60 - 35 = 25 degrees. A high Pelvic Tilt (normal is usually < 20 degrees) indicates pelvic retroversion. Pelvic retroversion is a primary compensatory mechanism for positive sagittal imbalance (often due to loss of lumbar lordosis) in an attempt to keep the center of gravity over the feet and maintain an upright posture.

Question 683

Topic: Thoracolumbar Spine & Deformity

When evaluating a patient for adult spinal deformity correction, achieving a harmonious sagittal profile is a primary goal to improve health-related quality of life. According to the SRS-Schwab classification, which of the following spinopelvic parameter combinations represents the ideal target for postoperative alignment?

. Pelvic Incidence (PI) minus Lumbar Lordosis (LL) < 10 degrees
. Pelvic Tilt (PT) > 25 degrees
. Sagittal Vertical Axis (SVA) > 50 mm
. Thoracic Kyphosis (TK) > Lumbar Lordosis (LL)
. Pelvic Incidence (PI) < Pelvic Tilt (PT)

Correct Answer & Explanation

. Pelvic Incidence (PI) minus Lumbar Lordosis (LL) < 10 degrees

Explanation

The SRS-Schwab classification established threshold values for optimal sagittal alignment in adult spinal deformity: PI - LL < 10 degrees, PT < 20 degrees, and SVA < 50 mm. Failure to achieve these targets strongly correlates with poorer health-related quality of life (HRQOL) scores, persistent pain, and higher rates of revision surgery due to proximal junctional kyphosis or implant failure.

Question 684

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male falls from a height of 15 feet and sustains a L1 fracture.

Imaging shows a burst fracture with 30% canal compromise. He is neurologically intact. MRI demonstrates an intact 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; conservative management
. Score 4; operative or non-operative management
. Score 5; operative management
. Score 7; operative management
. Score 3; conservative management

Correct Answer & Explanation

. Score 2; conservative management

Explanation

In the Thoracolumbar Injury Classification and Severity (TLICS) system, points are awarded for morphology (Burst = 2 points), neurologic status (Intact = 0 points), and PLC integrity (Intact = 0 points). The total score is 2. A score of 3 or less indicates non-operative management. A score of 4 is indeterminate (surgeon's choice), and 5 or more dictates operative intervention.

Question 685

Topic: Thoracolumbar Spine & Deformity
A 65-year-old woman is evaluated for a debilitating flatback deformity and sagittal imbalance. Figure 39 represents a templated standing lateral radiograph. Measurement of her spino-pelvic parameters reveals a pelvic incidence (PI) of 56 degrees and a sacral slope (SS) of 22 degrees. What is her calculated pelvic tilt (PT), and what is the generally accepted target for her postoperative lumbar lordosis (LL)?
. PT = 34 degrees; Target LL = 46-56 degrees
. PT = 78 degrees; Target LL = 46-56 degrees
. PT = 34 degrees; Target LL = 20-30 degrees
. PT = 78 degrees; Target LL = 20-30 degrees
. PT = 22 degrees; Target LL = 66-76 degrees

Correct Answer & Explanation

. PT = 34 degrees; Target LL = 46-56 degrees

Explanation

The formula relating the key pelvic parameters is Pelvic Incidence (PI) = Pelvic Tilt (PT) + Sacral Slope (SS). Given PI = 56 and SS = 22, the PT is 56 - 22 = 34 degrees. For optimal postoperative sagittal alignment and minimization of adjacent segment disease and hardware failure, the target Lumbar Lordosis (LL) should be restored to within 10 degrees of the patient's PI (i.e., PI - LL ≤ 10 degrees). Therefore, an appropriate target LL for this patient is between 46 and 56 degrees.

Question 686

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman presents with severe low back pain, global sagittal imbalance, and difficulty standing upright. Standing full-length lateral radiographs show a pelvic incidence (PI) of 60 degrees, lumbar lordosis (LL) of 30 degrees, and a sagittal vertical axis (SVA) of 12 cm. What is the approximate target lumbar lordosis required to achieve an optimal sagittal balance in this patient if surgical correction is planned?

. 30 degrees
. 40 degrees
. 60 degrees
. 75 degrees
. 90 degrees

Correct Answer & Explanation

. 30 degrees

Explanation

The relationship between pelvic incidence (PI) and lumbar lordosis (LL) is critical in correcting adult spinal deformity. According to the Schwab criteria, normal sagittal balance typically requires the LL to be within 10 degrees of the PI (PI - LL < 10°). In this patient with a PI of 60 degrees, the target LL should be approximately 60 degrees (acceptable range 50-70 degrees). An LL of 30 degrees leaves the patient with a significant PI-LL mismatch of 30 degrees, leading to a positive sagittal vertical axis (SVA) and compensatory mechanisms such as pelvic retroversion and knee flexion.

Question 687

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman presents with severe mechanical back pain and difficulty standing upright. Radiographs reveal a pelvic incidence (PI) of 65°, lumbar lordosis (LL) of 30°, pelvic tilt (PT) of 35°, and a sagittal vertical axis (SVA) of +12 cm. She has failed extensive nonoperative management. If surgical correction is planned, what is the primary sagittal alignment goal to optimize her clinical outcome?

. Decrease pelvic tilt to 0°
. Restore lumbar lordosis to within 10° of her pelvic incidence
. Reduce the SVA to less than 10 cm
. Increase thoracic kyphosis to match the pelvic incidence
. Match the lumbar lordosis to the pelvic tilt

Correct Answer & Explanation

. Restore lumbar lordosis to within 10° of her pelvic incidence

Explanation

In adult spinal deformity, restoring sagittal balance is highly correlated with improved clinical outcomes (e.g., ODI scores). The key parameters include a sagittal vertical axis (SVA) < 5 cm, a pelvic tilt (PT) < 20°, and a mismatch between pelvic incidence (PI) and lumbar lordosis (LL) of < 10° (PI - LL < 10°). Because PI is a fixed anatomic parameter, the surgical goal is to increase LL to closely match the PI.

Question 688

Topic: Thoracolumbar Spine & Deformity

A 32-year-old construction worker falls from a height of 10 feet and sustains an isolated L1 burst fracture. He is neurologically intact. Upright radiographs demonstrate 15° of regional kyphosis and 30% loss of anterior vertebral body height. CT scan shows retropulsion of the posterosuperior vertebral body fragment occluding 25% of the spinal canal. The posterior ligamentous complex (PLC) is intact on MRI. According to the Thoracolumbar Injury Classification and Severity (TLICS) system, what is his total score and the recommended treatment pathway?

. TLICS score 2; nonoperative management
. TLICS score 4; operative management
. TLICS score 4; surgeon's choice of operative or nonoperative management
. TLICS score 5; operative management
. TLICS score 6; operative management

Correct Answer & Explanation

. TLICS score 2; nonoperative management

Explanation

The Thoracolumbar Injury Classification and Severity (TLICS) score evaluates injury morphology, integrity of the posterior ligamentous complex (PLC), and neurologic status. For this patient: Morphology is a burst fracture (2 points); PLC is intact (0 points); Neurologic status is intact (0 points). The total TLICS score is 2. A score of 3 or less indicates nonoperative management. A score of 4 can be treated operatively or nonoperatively (surgeon's choice), and a score of 5 or more dictates operative stabilization.

Question 689

Topic: Thoracolumbar Spine & Deformity

A 40-year-old male is brought to the trauma bay after falling from a 15-foot ladder. He is neurologically intact with full motor strength and normal sensation in the lower extremities.

CT imaging shows an L1 burst fracture with a 30% loss of anterior vertebral body height and 15% canal compromise. An MRI reveals an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his score and the recommended management?

. TLICS score 1; conservative management
. TLICS score 2; conservative management
. TLICS score 4; operative management
. TLICS score 5; operative management
. TLICS score 7; operative management

Correct Answer & Explanation

. TLICS score 2; conservative management

Explanation

The TLICS system scores based on injury morphology, neurologic status, and the integrity of the posterior ligamentous complex (PLC). Burst fracture morphology = 2 points. Neurologically intact = 0 points. Intact PLC = 0 points. The total score is 2. A TLICS score of 3 or less suggests nonoperative management (e.g., TLSO bracing). A score of 4 is considered a gray area (surgeon's choice), and a score of 5 or more indicates operative intervention.

Question 690

Topic: Thoracolumbar Spine & Deformity

A 14-year-old competitive gymnast presents with a 9-month history of severe, unrelenting low back pain. She denies any leg pain, numbness, or weakness. Radiographs demonstrate a Grade II L5-S1 isthmic spondylolisthesis. She has failed to improve despite 6 months of rest, NSAIDs, and a targeted physical therapy program. What is the most appropriate surgical intervention?

. Direct repair of the pars interarticularis (e.g., Buck's or Scott's wiring)
. L5-S1 instrumented posterolateral fusion
. L4-S1 instrumented posterolateral fusion
. L5 laminectomy without fusion
. Anterior lumbar interbody fusion (ALIF) at L4-L5

Correct Answer & Explanation

. L5-S1 instrumented posterolateral fusion

Explanation

In an adolescent with a symptomatic Grade II isthmic spondylolisthesis who has failed exhaustive conservative management, the gold standard surgical treatment is an L5-S1 posterolateral fusion (with or without interbody fusion). Direct pars repair is generally reserved for patients with Grade I or less slips, typically at L4 or above, without significant disc degeneration. Laminectomy alone is contraindicated in this age group due to the risk of progressive instability and slip progression.

Question 691

Topic: Thoracolumbar Spine & Deformity
A 68-year-old female presents with progressive difficulty standing upright and severe mechanical low back pain. Full-length standing radiographs demonstrate significant adult spinal deformity. Her measured spino-pelvic parameters are: Pelvic Incidence (PI) = 58 degrees, Pelvic Tilt (PT) = 32 degrees, and Lumbar Lordosis (LL) = 20 degrees. To restore optimal sagittal alignment and minimize the risk of mechanical failure or adjacent segment disease postoperatively, what should the target Lumbar Lordosis be?
. 10 to 20 degrees
. 25 to 35 degrees
. 48 to 58 degrees
. 65 to 75 degrees
. 80 to 90 degrees

Correct Answer & Explanation

. 48 to 58 degrees

Explanation

According to the Schwab criteria for adult spinal deformity correction, optimal sagittal balance is achieved when the mismatch between Pelvic Incidence (PI) and Lumbar Lordosis (LL) is within 10 degrees (PI - LL ≤ 10°). Given a PI of 58 degrees, the ideal postoperative LL should be at least 48 degrees, making 48 to 58 degrees the correct target range.

Question 692

Topic: Thoracolumbar Spine & Deformity

In evaluating a 60-year-old woman for adult spinal deformity, her standing full-length lateral radiograph reveals a pelvic incidence (PI) of 65 degrees, pelvic tilt (PT) of 30 degrees, and lumbar lordosis (LL) of 35 degrees. Which of the following best describes her spinopelvic alignment?

. Normal spinopelvic alignment
. PI-LL mismatch of 30 degrees
. PI-LL mismatch of 0 degrees
. PT is within normal limits
. LL is excessive for her PI

Correct Answer & Explanation

. PI-LL mismatch of 30 degrees

Explanation

The PI-LL mismatch is calculated as Pelvic Incidence minus Lumbar Lordosis. In this patient, 65 - 35 = 30 degrees. A normal PI-LL mismatch should be within 10 degrees (ideally PI = LL +/- 9 degrees). A mismatch of 30 degrees indicates a significant flatback deformity. Her PT is also elevated (normal < 20 degrees), indicating pelvic retroversion as a compensatory mechanism to maintain upright posture.

Question 693

Topic: Thoracolumbar Spine & Deformity

In the assessment of sagittal balance for adult spinal deformity, Pelvic Incidence (PI) is a constant morphological parameter unaffected by posture. Which of the following equations correctly describes the relationship between Pelvic Incidence (PI), Pelvic Tilt (PT), and Sacral Slope (SS)?

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

Correct Answer & Explanation

. PI = PT + SS

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter unique to each individual and is defined geometrically as the sum of Pelvic Tilt (PT) and Sacral Slope (SS). Therefore, PI = PT + SS. As a patient loses lumbar lordosis, they often retrovert their pelvis to compensate, which increases PT and decreases SS, while PI remains constant.

Question 694

Topic: Thoracolumbar Spine & Deformity

A 65-year-old female presents with progressive low back pain and difficulty standing upright. She has to bend her knees to look straight ahead. Radiographic analysis reveals a pelvic incidence (PI) of 60 degrees, a lumbar lordosis (LL) of 25 degrees, and a sagittal vertical axis (SVA) of +12 cm. She has failed all conservative management. What is the most critical radiographic goal of her surgical correction?

. Correction of Coronal Cobb angle to less than 10 degrees
. Restoration of Lumbar Lordosis (LL) to within 10 degrees of Pelvic Incidence (PI)
. Achieving a pelvic tilt (PT) of greater than 30 degrees
. Maintaining a Sagittal Vertical Axis (SVA) of exactly 0 cm
. Correction of thoracic kyphosis to less than 20 degrees

Correct Answer & Explanation

. Restoration of Lumbar Lordosis (LL) to within 10 degrees of Pelvic Incidence (PI)

Explanation

In adult spinal deformity, restoring sagittal balance is highly correlated with improved patient outcomes (HRQOL scores). The accepted radiographic goals defined by the Scoliosis Research Society (SRS) include maintaining a Sagittal Vertical Axis (SVA) < 5 cm, a Pelvic Tilt (PT) < 20 degrees, and a PI-LL mismatch within +/- 9 degrees. Achieving a PI-LL mismatch of less than 10 degrees is crucial to restoring global sagittal alignment and reducing compensatory mechanisms like knee flexion.

Question 695

Topic: Thoracolumbar Spine & Deformity

A 35-year-old construction worker falls from a 15-foot scaffolding, sustaining severe middle back pain. Neurological examination is intact bilaterally (ASIA E). A CT scan of the thoracic spine demonstrates a T12 burst fracture with 40% loss of anterior vertebral body height, 15 degrees of focal kyphosis, and a vertical splitting fracture of the lamina. An MRI reveals fluid signal and disruption of the posterior ligamentous complex (PLC). Based on the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

. Jewett brace and early mobilization
. Thoracolumbosacral orthosis (TLSO) for 12 weeks
. Prolonged bed rest for 6 weeks followed by bracing
. Surgical stabilization
. Anterior vertebrectomy alone

Correct Answer & Explanation

. Surgical stabilization

Explanation

The Thoracolumbar Injury Classification and Severity (TLICS) score evaluates three parameters: fracture morphology, neurologic status, and posterior ligamentous complex (PLC) integrity. Burst fracture = 2 points. Intact neurologic status = 0 points. Disrupted PLC = 3 points. The total score is 5. A TLICS score of > 4 is an indication for surgical stabilization. A score of 3 or less is typically treated non-surgically, while 4 is indeterminate.

Question 696

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with a 6-month history of mechanical low back pain. Radiographs demonstrate a Grade II L5-S1 spondylolisthesis. Advanced imaging confirms bilateral pars interarticularis defects at L5. She has failed 6 months of physical therapy, bracing, and NSAIDs. Her pain restricts her activities of daily living and sports. What is the most appropriate surgical treatment?

. L5 pars defect direct repair
. L4-L5 posterior spinal fusion
. L5-S1 posterolateral fusion with or without interbody fusion
. L5-S1 artificial disc replacement
. Sacroiliac joint fusion

Correct Answer & Explanation

. L5-S1 posterolateral fusion with or without interbody fusion

Explanation

In symptomatic adolescent isthmic spondylolisthesis (Grade I or II) that has failed extensive conservative management, L5-S1 fusion (posterolateral with or without interbody) is the gold standard. Direct pars repair (e.g., Buck's or Scott's wiring) is generally reserved for patients with pars defects without significant slip, and is more commonly performed at L4 or above, as L5 is technically difficult and less reliable for direct repair. Artificial disc replacement is contraindicated in the presence of instability and pars defects.

Question 697

Topic: Thoracolumbar Spine & Deformity

A 65-year-old woman presents with severe low back pain and leaning forward when walking. Standing lateral radiographs show a Pelvic Incidence (PI) of 60 degrees, Pelvic Tilt (PT) of 35 degrees, and Lumbar Lordosis (LL) of 20 degrees. Her Sagittal Vertical Axis (SVA) is +12 cm. What is the goal of surgical correction for this patient based on the SRS-Schwab classification?

. LL = 20 degrees, PT < 20 degrees, SVA < 5 cm
. LL = 60 degrees, PT < 20 degrees, SVA < 5 cm
. LL = 40 degrees, PT < 30 degrees, SVA < 10 cm
. LL = 60 degrees, PT < 30 degrees, SVA < 10 cm
. LL = 40 degrees, PT < 20 degrees, SVA < 5 cm

Correct Answer & Explanation

. LL = 60 degrees, PT < 20 degrees, SVA < 5 cm

Explanation

Based on the SRS-Schwab classification for adult spinal deformity, surgical correction goals to achieve ideal sagittal alignment include matching the Lumbar Lordosis (LL) to the Pelvic Incidence (PI) within 9 degrees (PI-LL < +/- 9 degrees). For a PI of 60 degrees, the target LL should be approximately 60 degrees. Additional goals include restoring Pelvic Tilt (PT) to < 20 degrees and Sagittal Vertical Axis (SVA) to < 5 cm. Option B accurately reflects all these goals.

Question 698

Topic: Thoracolumbar Spine & Deformity

A 30-year-old man presents to the trauma bay after falling 10 feet from a ladder. He complains of moderate low back pain. He is neurologically intact with 5/5 strength in all myotomes and normal bowel/bladder function.

A CT scan shows an L2 burst fracture with 20% loss of anterior vertebral body height, 10 degrees of regional kyphosis, 30% canal compromise, and an intact posterior osseous-ligamentous complex. What is the recommended treatment?

. Posterior short-segment pedicle screw fixation one level above and below
. Anterior corpectomy, structural cage placement, and anterolateral plating
. Conservative management with a thoracolumbosacral orthosis (TLSO) and early mobilization
. Laminectomy and posterior non-instrumented fusion
. Percutaneous balloon kyphoplasty of L2

Correct Answer & Explanation

. Conservative management with a thoracolumbosacral orthosis (TLSO) and early mobilization

Explanation

Thoracolumbar burst fractures with a Thoracolumbar Injury Classification and Severity (TLICS) score of less than 4 (neurologically intact, intact posterior ligamentous complex, stable height loss/kyphosis) are generally considered stable. Multiple randomized controlled trials have demonstrated that stable thoracolumbar burst fractures in neurologically intact patients have equivalent long-term functional outcomes when treated non-operatively with bracing (TLSO) or early mobilization compared to surgical fixation.

Question 699

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with persistent lower back pain that has prevented her from participating in sports for the past 8 months. She has undergone extensive physical therapy, bracing, and activity modification without relief. Radiographs reveal a Grade II isthmic spondylolisthesis at L5-S1 with 35% translation. Her neurologic examination is intact. What is the recommended surgical procedure for this patient?

. L5 bilateral pars interarticularis defect repair
. L5-S1 posterior instrumented fusion with autogenous bone graft
. L5 laminectomy and bilateral discectomy without fusion
. L4-S1 anterior and posterior combined spinal fusion
. Sacroiliac joint fusion

Correct Answer & Explanation

. L5-S1 posterior instrumented fusion with autogenous bone graft

Explanation

In pediatric patients with a symptomatic, high-grade isthmic spondylolisthesis (or a symptomatic low-grade slip that has completely failed comprehensive non-operative management), an L5-S1 posterior instrumented fusion with bone grafting is the standard of care. Direct pars repairs are generally reserved for young patients with early-stage spondylolysis (defect only) or very minimal Grade I slips, typically at the L1-L4 levels rather than L5-S1 due to biomechanical stresses. A laminectomy alone is strictly contraindicated as it will aggressively destabilize the segment and dramatically worsen the slip.

Question 700

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman presents with progressively worsening lower back pain and an inability to stand completely upright. She notes that she must consciously bend her knees to maintain a forward gaze. Standing full-length scoliosis radiographs reveal a Pelvic Incidence (PI) of 60 degrees, a Lumbar Lordosis (LL) of 20 degrees, and a Sagittal Vertical Axis (SVA) of +12 cm. What is the primary radiographic goal in the surgical correction of her adult spinal deformity?

. Restore her Lumbar Lordosis to equal her Pelvic Incidence minus 40 degrees
. Achieve a postoperative Sagittal Vertical Axis of greater than 10 cm
. Restore her Lumbar Lordosis to within 10 degrees of her Pelvic Incidence
. Surgically correct her Pelvic Incidence to match her 20 degrees of Lumbar Lordosis
. Perform a single-level L5-S1 ALIF to increase anterior column height

Correct Answer & Explanation

. Restore her Lumbar Lordosis to within 10 degrees of her Pelvic Incidence

Explanation

In the surgical management of adult spinal deformity, restoring regional and global sagittal balance is paramount for favorable clinical outcomes. The widely accepted goal is to restore the patient's Lumbar Lordosis (LL) to within 10 degrees of their fixed Pelvic Incidence (PI) (i.e., PI - LL < 10 degrees). The Sagittal Vertical Axis (SVA) should ideally be corrected to less than 5 cm. Pelvic Incidence is a fixed, innate morphologic parameter of the pelvis and cannot be surgically altered or 'corrected.'

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