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Thoracolumbar Spine & Deformity MCQs

Practice Set 33 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 641

Topic: Thoracolumbar Spine & Deformity

A 25-year-old man falls from a roof and sustains an L1 burst fracture. He is neurologically intact. CT scan shows 30% canal compromise and kyphosis of 15 degrees. MRI confirms an intact posterior ligamentous complex (PLC). What is the most appropriate management?

. Thoracolumbosacral orthosis (TLSO) bracing
. Short-segment posterior spinal fusion
. Long-segment posterior spinal fusion
. Anterior corpectomy and fusion
. Percutaneous pedicle screw fixation without fusion

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing

Explanation

Thoracolumbar burst fractures in neurologically intact patients with an intact posterior ligamentous complex (TLICS score < 4) can be treated successfully with a rigid brace (TLSO). Surgery is not indicated for stable burst fractures without neurologic deficit.

Question 642

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast complains of localized low back pain exacerbated by extension activities. Oblique lumbar radiographs demonstrate a "Scotty dog with a collar" sign. What is the precise anatomical location of the defect indicated by the "collar"?

. Pars interarticularis
. Pedicle
. Lamina
. Transverse process
. Spinous process

Correct Answer & Explanation

. Pars interarticularis

Explanation

The "collar" on the Scotty dog sign seen on oblique lumbar radiographs represents a defect or fracture in the pars interarticularis, which is the pathognomonic hallmark of spondylolysis.

Question 643

Topic: Thoracolumbar Spine & Deformity

A 16-year-old female presents after a high-speed motor vehicle collision where she was wearing only a lap belt. Imaging shows a horizontal fracture through the spinous process, pedicles, and vertebral body of L2 (Chance fracture). Which associated injury must be actively ruled out in this patient?

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

Correct Answer & Explanation

. Aortic transection

Explanation

Chance fractures are flexion-distraction injuries highly associated with lap-belt use. Up to 50% of patients with a Chance fracture have an associated intra-abdominal hollow viscus injury (e.g., bowel perforation), which requires immediate general surgery evaluation.

Question 644

Topic: Thoracolumbar Spine & Deformity

In the evaluation of adult spinal deformity, which of the following spinopelvic parameters is considered a fixed, position-independent anatomical constant for an individual after they reach skeletal maturity?

. Pelvic tilt (PT)
. Sacral slope (SS)
. Pelvic incidence (PI)
. Lumbar lordosis (LL)
. Thoracic kyphosis (TK)

Correct Answer & Explanation

. Pelvic tilt (PT)

Explanation

Pelvic incidence (PI) is a morphological parameter that becomes fixed after skeletal maturity. It is critical in pre-operative planning as it dictates the required amount of lumbar lordosis for a balanced spine (LL = PI ± 9 degrees).

Question 645

Topic: Thoracolumbar Spine & Deformity

A 35-year-old man falls from a height and sustains a thoracolumbar fracture. CT shows a burst fracture of L1 with splaying of the posterior elements indicating a posterior ligamentous complex (PLC) injury. Neurologic examination is normal. Based on the Thoracolumbar Injury Classification and Severity Score (TLICS), what is the most appropriate treatment?

. TLSO brace and early mobilization
. Bed rest for 6 weeks
. Posterior spinal instrumentation and fusion
. Stand-alone anterior vertebrectomy
. Epidural steroid injection

Correct Answer & Explanation

. TLSO brace and early mobilization

Explanation

This patient has a burst fracture (2 points), a disrupted PLC indicated by splayed posterior elements (3 points), and intact neurology (0 points), totaling a TLICS score of 5. A score greater than 4 is an indication for surgical stabilization.

Question 646

Topic: Thoracolumbar Spine & Deformity

A 22-year-old female presents after a high-speed motor vehicle collision. Radiographs demonstrate a flexion-distraction injury (Chance fracture) at L1. Which of the following is the most commonly associated concomitant injury?

. Aortic transection
. Renal laceration
. Intra-abdominal hollow viscus injury
. Pulmonary contusion
. Pelvic ring disruption

Correct Answer & Explanation

. Aortic transection

Explanation

Chance fractures are typically caused by seatbelt injuries and involve failure of the posterior and middle columns under tension. They have a high association (up to 40-50%) with intra-abdominal hollow viscus injuries, such as bowel perforations.

Question 647

Topic: Thoracolumbar Spine & Deformity

A 15-year-old female gymnast presents with persistent, activity-limiting low back pain for 8 months. Radiographs demonstrate bilateral L5 pars interarticularis defects with no evidence of spondylolisthesis. She has failed a 6-month trial of bracing, rest, and physical therapy. What is the most appropriate surgical management?

. L4-S1 posterior decompression without fusion
. L5-S1 instrumented posterolateral fusion
. Direct pars repair
. Anterior lumbar interbody fusion (ALIF)

Correct Answer & Explanation

. L4-S1 posterior decompression without fusion

Explanation

In a young athlete with a symptomatic pars defect (spondylolysis) without spondylolisthesis that has failed conservative care, a direct pars repair is indicated. This approach preserves the motion segment and allows a return to high-demand activities.

Question 648

Topic: Thoracolumbar Spine & Deformity

A 28-year-old male is evaluated after a fall from a height of 10 feet. CT scans show an L1 burst fracture with 20 degrees of kyphosis and 30% canal compromise. The posterior ligamentous complex is intact. He is neurologically intact. Using the Thoracolumbar Injury Classification and Severity (TLICS) system, what is the recommended management?

. TLSO bracing and early mobilization
. Short-segment posterior spinal fusion
. Anterior corpectomy and fusion
. Posterior laminectomy alone

Correct Answer & Explanation

. TLSO bracing and early mobilization

Explanation

The TLICS score for this patient is 2: burst fracture mechanism (2), intact neurology (0), and intact posterior ligamentous complex (0). Scores of 3 or less dictate non-operative management, typically with a TLSO brace.

Question 649

Topic: Thoracolumbar Spine & Deformity

A 22-year-old female involved in a head-on motor vehicle collision while wearing a lap-only seatbelt sustains a flexion-distraction injury (Chance fracture) of L2. Based on the mechanism of injury, she should be urgently evaluated for which highly associated concomitant injury?

. Thoracic aortic tear
. Intra-abdominal hollow viscus injury
. Diaphragmatic rupture
. Renal artery thrombosis

Correct Answer & Explanation

. Thoracic aortic tear

Explanation

Chance fractures are flexion-distraction injuries commonly caused by a lap seatbelt acting as a fulcrum. They carry a 40-50% association with concurrent intra-abdominal injuries, particularly hollow viscus ruptures.

Question 650

Topic: Thoracolumbar Spine & Deformity

A 40-year-old male falls from a ladder and sustains an L2 burst fracture. He is neurologically intact. An MRI confirms disruption of the posterior ligamentous complex (PLC). What is his Thoracolumbar Injury Classification and Severity (TLICS) score and recommended treatment?

. Score 2; Nonoperative management with a TLSO brace
. Score 4; Surgeon's choice of operative or nonoperative management
. Score 5; Operative management
. Score 7; Operative management

Correct Answer & Explanation

. Score 2; Nonoperative management with a TLSO brace

Explanation

The TLICS score is 5: morphology is burst (2 points), neurological status is intact (0 points), and the PLC is disrupted (3 points). A score of 5 or greater is an indication for operative stabilization.

Question 651

Topic: Thoracolumbar Spine & Deformity

An 18-year-old restrained passenger in a high-speed collision presents with severe lower back pain. Radiographs demonstrate a transverse fracture through the L2 pedicles and vertebral body with posterior element distraction. Which of the following associated conditions must be most urgently evaluated?

. Aortic transection
. Blunt cardiac injury
. Intra-abdominal hollow viscus injury
. Diaphragmatic rupture

Correct Answer & Explanation

. Aortic transection

Explanation

The patient has a Chance fracture (flexion-distraction injury), which is highly associated with seatbelt injuries. There is a high incidence (up to 50%) of concurrent intra-abdominal hollow viscus injuries that require urgent general surgery evaluation.

Question 652

Topic: Thoracolumbar Spine & Deformity

When evaluating the sagittal balance of a patient presenting with degenerative lumbar spondylolisthesis, which of the following formulas accurately describes the relationship between key spinopelvic parameters?

. Pelvic Incidence = Pelvic Tilt + Sacral Slope
. Pelvic Tilt = Pelvic Incidence + Sacral Slope
. Sacral Slope = Pelvic Incidence + Pelvic Tilt
. Pelvic Incidence = Pelvic Tilt - Sacral Slope

Correct Answer & Explanation

. Pelvic Incidence = Pelvic Tilt + Sacral Slope

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter defined as the sum of pelvic tilt (PT) and sacral slope (SS). This equation (PI = PT + SS) is fundamental in planning deformity correction and sagittal realignment.

Question 653

Topic: Thoracolumbar Spine & Deformity

When placing lumbar pedicle screws using standard open anatomical landmarks, what is the accepted entry point?

. The intersection of the pars interarticularis and the inferior articular process
. The intersection of a line bisecting the transverse process and the lateral border of the superior articular process
. The medial border of the superior articular process and the superior border of the transverse process
. The lamina-spinous process junction
. The inferior border of the transverse process and the medial pars

Correct Answer & Explanation

. The intersection of the pars interarticularis and the inferior articular process

Explanation

The standard entry point for a lumbar pedicle screw is the intersection of a horizontal line bisecting the transverse process and a vertical line tangent to the lateral border of the superior articular facet.

Question 654

Topic: Thoracolumbar Spine & Deformity

A 14-year-old male athlete presents with lower back pain and notably tight hamstrings. A lateral lumbar radiograph reveals a grade II isthmic spondylolisthesis at L5-S1.

He has failed 6 months of nonoperative management, including bracing, physical therapy, and activity modification. What is the most appropriate surgical treatment?

. Pars repair with bone grafting
. L5-S1 in situ posterolateral arthrodesis
. L5 laminectomy without fusion
. L5-S1 anterior lumbar interbody fusion (ALIF) alone
. Epidural steroid injections

Correct Answer & Explanation

. L5-S1 in situ posterolateral arthrodesis

Explanation

For pediatric and adolescent patients with symptomatic low-grade (Grade I or II) isthmic spondylolisthesis who fail comprehensive conservative management, L5-S1 in situ posterolateral arthrodesis is the surgical standard of care. Pars repairs (e.g., Buck or Scott wiring) are generally reserved for young patients with a pars defect but minimal or no slip (typically L1-L4, not L5-S1). Laminectomy alone is contraindicated in children as it promotes instability and further slippage.

Question 655

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female gymnast presents with persistent lower back pain. Radiographs reveal an isthmic spondylolisthesis at L5-S1 with a slip of 60% (Meyerding Grade III). She has failed 6 months of nonoperative management. What is the most appropriate surgical intervention?
. Pars interarticularis defect repair directly
. L5-S1 laminectomy and decompression alone
. L5-S1 in situ posterolateral fusion
. L4-S1 posterior spinal fusion without instrumentation
. Cervical to sacral spinal fusion

Correct Answer & Explanation

. L5-S1 in situ posterolateral fusion

Explanation

For symptomatic high-grade (>50% slip) isthmic spondylolisthesis that fails conservative care, L5-S1 in situ posterolateral fusion (typically with instrumentation) is the standard treatment to prevent further progression.

Question 656

Topic: Thoracolumbar Spine & Deformity

A 68-year-old man presents with recurrent posterior instability of his THA. He has a history of L5-S1 fusion prior to his THA. What is the most likely biomechanical cause of his recurrent instability?

. Decreased pelvic tilt in sitting position leading to functional retroversion of the acetabular component.
. Increased pelvic tilt in standing position leading to functional anteversion of the acetabular component.
. Anterior impingement of the femoral neck on the acetabulum during extension.
. Decreased spinopelvic mobility leading to hyperlordosis in sitting.
. Impaired abductor function due to superior gluteal nerve injury.

Correct Answer & Explanation

. Decreased pelvic tilt in sitting position leading to functional retroversion of the acetabular component.

Explanation

Patients with stiff spinopelvic segments (e.g., prior lumbar fusion) lack the normal posterior pelvic tilt that occurs when moving from standing to sitting. Normally, posterior pelvic tilt increases functional anteversion to accommodate hip flexion and prevent anterior impingement. In patients with a stiff spine, the pelvis fails to tilt posteriorly during sitting, leaving the cup relatively retroverted and the hip prone to anterior impingement and posterior dislocation.

Question 657

Topic: Thoracolumbar Spine & Deformity
When planning corrective surgery for adult spinal deformity, achieving optimal sagittal balance has been shown to strongly correlate with improved health-related quality of life (HRQOL) scores. According to the SRS-Schwab classification, which of the following is a primary radiographic target for sagittal realignment?
. Pelvic incidence minus lumbar lordosis (PI - LL) less than or equal to 10 degrees
. Sagittal vertical axis (SVA) greater than 5 cm
. Pelvic tilt (PT) greater than 25 degrees
. Thoracic kyphosis less than 20 degrees
. Lumbar lordosis greater than 60 degrees regardless of pelvic incidence

Correct Answer & Explanation

. Pelvic incidence minus lumbar lordosis (PI - LL) less than or equal to 10 degrees

Explanation

The SRS-Schwab classification of adult spinal deformity emphasizes three key sagittal modifiers that correlate closely with pain and disability: 1) Sagittal vertical axis (SVA) < 50 mm, 2) Pelvic Tilt (PT) < 20 degrees, and 3) Mismatch between Pelvic Incidence and Lumbar Lordosis (PI - LL) ≤ 10 degrees. Achieving a PI-LL mismatch of less than 10 degrees is a critical surgical target to restore proper spinopelvic harmony.

Question 658

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with persistent lower back pain for 8 months. She has no radiating leg pain and a normal neurologic examination. Radiographs reveal a Grade I isthmic spondylolisthesis at L5-S1. She has exhausted 6 months of nonoperative management, including bracing and physical therapy. What is the most appropriate surgical intervention?

. L5-S1 anterior lumbar interbody fusion (ALIF)
. L5-S1 posterior instrumented fusion with autogenous bone graft
. Direct repair of the pars interarticularis (pars repair)
. L5 laminectomy without fusion
. L4-S1 posterior instrumented fusion

Correct Answer & Explanation

. L5-S1 posterior instrumented fusion with autogenous bone graft

Explanation

For an adolescent with symptomatic Grade I isthmic spondylolisthesis at L5-S1 that has failed extensive nonoperative management, an in situ L5-S1 posterior instrumented fusion with autogenous bone grafting is the gold standard of treatment. A direct pars repair (e.g., Buck's or Scott's wiring) is typically reserved for symptomatic L1-L4 spondylolysis without a significant slip. Laminectomy alone in a pediatric patient is contraindicated as it exacerbates instability.

Question 659

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male is evaluated after falling from a ladder. Examination demonstrates completely intact motor and sensory function in his bilateral lower extremities, with normal rectal tone. CT scan reveals a T12 burst fracture with 30% canal compromise and 10 degrees of focal kyphosis. MRI confirms an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) system, what is the patient's score and the recommended treatment?

. Score 2, non-operative management
. Score 4, operative or non-operative management
. Score 5, operative management
. Score 7, operative management
. Score 3, non-operative management

Correct Answer & Explanation

. Score 2, non-operative management

Explanation

The TLICS system assigns points based on three categories: 1) Morphology: Burst fracture = 2 points. 2) Neurologic status: Intact = 0 points. 3) Posterior Ligamentous Complex (PLC): Intact = 0 points. The total score is 2. A TLICS score of 3 or less is typically managed non-operatively (e.g., TLSO brace). A score of 4 is indeterminate (surgeon's choice), and a score of 5 or more dictates operative intervention.

Question 660

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female gymnast presents with progressive low back pain and tight hamstrings. Standing lateral lumbar radiographs reveal an isthmic spondylolisthesis at L5-S1 with a 60% slip (Meyerding Grade III). Which of the following radiographic parameters is the most significant predictor of further slip progression in this patient?
. High slip angle (lumbosacral kyphosis)
. Low pelvic incidence
. Presence of spina bifida occulta
. Sacral doming
. Increased lumbar lordosis

Correct Answer & Explanation

. High slip angle (lumbosacral kyphosis)

Explanation

In pediatric and adolescent isthmic or dysplastic spondylolisthesis, a high slip angle (also known as lumbosacral kyphosis) is the most significant radiographic predictor for the risk of further progression of the slip. A high slip angle indicates severe local kyphotic deformity at the lumbosacral junction, which alters the biomechanical shear forces, making progressive anterior translation highly likely. Other risk factors for progression include high pelvic incidence, age (immature skeleton), and female gender, but slip angle remains the strongest radiographic predictor.

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