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Thoracolumbar Spine & Deformity MCQs

Practice Set 46 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 901

Topic: Thoracolumbar Spine & Deformity

Which of the following describes the anatomical anomaly defining Wiltse-Newman Type V spondylolisthesis?

. Sustained stress fracture of the pars interarticularis
. Degeneration of the intervertebral disc and facet joints
. Bone weakened by disease, such as tumor or osteoporosis
. Acute traumatic fracture of the inferior articular process
. Congenital dysplastic elements of the L5 vertebra and sacrum

Correct Answer & Explanation

. Bone weakened by disease, such as tumor or osteoporosis

Explanation

Wiltse-Newman Type V, or Pathologic Spondylolisthesis, results from bone weakening due to generalized or localized bone disease, such as tumors (primary or metastatic), Paget's disease, or severe osteoporosis, which compromises the structural integrity of the vertebral segment and leads to slippage. Other options describe different types of spondylolisthesis.

Question 902

Topic: Thoracolumbar Spine & Deformity

You are discussing the role of bracing for scoliosis in adolescents. To demonstrate a nuanced understanding for the examiner, you should emphasize:

. That bracing always prevents curve progression.
. Bracing is ineffective and rarely used.
. The specific indications (e.g., Risser sign, curve magnitude, remaining growth potential), the goal of bracing (to prevent progression, not correct the curve), and the importance of patient compliance.
. That surgery is always the best option for scoliosis.
. Focusing on the cosmetic aspect of bracing only.

Correct Answer & Explanation

. The specific indications (e.g., Risser sign, curve magnitude, remaining growth potential), the goal of bracing (to prevent progression, not correct the curve), and the importance of patient compliance.

Explanation

For scoliosis bracing, a high-scoring answer requires understanding the specific indications, the biomechanical principles, and, crucially, the realistic goals. Bracing aims to halt or slow progression in skeletally immature patients with moderate curves, not to correct them. Patient compliance is paramount for success. Discussing these factors demonstrates a comprehensive grasp of the management strategy.

Question 903

Topic: Thoracolumbar Spine & Deformity

In adult spinal deformity surgery, achieving appropriate sagittal balance is critical for good clinical outcomes. According to the SRS-Schwab classification, which of the following spinopelvic parameter targets is most strongly correlated with improved health-related quality of life (HRQOL)?

. Pelvic incidence minus lumbar lordosis (PI-LL) < 10 degrees
. Pelvic tilt (PT) > 20 degrees
. Sagittal vertical axis (SVA) > 5 cm
. Sacral slope (SS) < 20 degrees
. Thoracic kyphosis (TK) > 40 degrees

Correct Answer & Explanation

. Pelvic incidence minus lumbar lordosis (PI-LL) < 10 degrees

Explanation

The SRS-Schwab targets for adult spinal deformity correction are: PI-LL < 10 degrees, PT < 20 degrees, and SVA < 5 cm. Normalizing PI-LL mismatch is paramount for surgical success.

Question 904

Topic: Thoracolumbar Spine & Deformity

Which of the following describes the correct formula defining the relationship between spinopelvic parameters in a standing individual?

. Pelvic Incidence (PI) = Pelvic Tilt (PT) + Sacral Slope (SS)
. Pelvic Tilt (PT) = Pelvic Incidence (PI) + Sacral Slope (SS)
. Sacral Slope (SS) = Pelvic Incidence (PI) + Pelvic Tilt (PT)
. Pelvic Incidence (PI) = Lumbar Lordosis (LL) + Pelvic Tilt (PT)
. Lumbar Lordosis (LL) = Pelvic Incidence (PI) + Sacral Slope (SS)

Correct Answer & Explanation

. Pelvic Incidence (PI) = Pelvic Tilt (PT) + Sacral Slope (SS)

Explanation

Pelvic incidence (PI) is a fixed morphological parameter defined as the sum of the pelvic tilt (PT) and the sacral slope (SS). PI = PT + SS. As a person changes position, the PT and SS change inversely, but PI remains constant.

Question 905

Topic: Thoracolumbar Spine & Deformity

In the setting of adult degenerative scoliosis, which radiographic parameter is considered the most significant predictor of patient-reported clinical outcomes and disability (e.g., ODI scores)?

. Coronal Cobb angle > 40 degrees
. Apical vertebral rotation
. Sagittal vertical axis (SVA) > 5 cm
. Lumbar lordosis > 60 degrees
. Thoracic kyphosis < 20 degrees

Correct Answer & Explanation

. Sagittal vertical axis (SVA) > 5 cm

Explanation

Positive sagittal balance, most commonly measured by a Sagittal Vertical Axis (SVA) greater than 5 cm, has been consistently shown in the literature to be the most significant radiographic predictor of poor patient-reported outcomes, pain, and disability (ODI) in adult spinal deformity.

Question 906

Topic: Thoracolumbar Spine & Deformity

A 28-year-old male is involved in a motor vehicle accident and sustains an L1 burst fracture with 40% loss of anterior vertebral body height and 30% canal compromise. He is neurologically intact, and MRI confirms the posterior ligamentous complex (PLC) is intact. According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is the appropriate management?

. Immediate surgical stabilization
. Non-operative management with a TLSO brace
. High-dose intravenous methylprednisolone
. Urgent laminectomy without fusion
. Anterior corpectomy and fusion

Correct Answer & Explanation

. Non-operative management with a TLSO brace

Explanation

The TLICS score for this patient is 2 (Morphology: burst = 2; Neurologic status: intact = 0; PLC: intact = 0). A TLICS score of 3 or less is an indication for non-operative management, typically with a rigid orthosis.

Question 907

Topic: Thoracolumbar Spine & Deformity

A 62-year-old female presents with neurogenic claudication. Radiographs demonstrate a grade 1 degenerative spondylolisthesis at L4-L5. Which of the following anatomical variations is most strongly associated with the development of degenerative spondylolisthesis at this level?

. Coronal orientation of the facet joints
. Pars interarticularis defect
. Sagittal orientation of the facet joints
. Pedicle hypoplasia
. Conjoined nerve root

Correct Answer & Explanation

. Sagittal orientation of the facet joints

Explanation

Degenerative spondylolisthesis is strongly associated with facet joint morphology. A more sagittal orientation of the facet joints provides less resistance to anterior shear forces, predisposing the segment to degenerative forward slip, most commonly at L4-L5.

Question 908

Topic: Thoracolumbar Spine & Deformity

A 30-year-old male falls from a ladder and sustains an L1 burst fracture. He is neurologically intact. MRI demonstrates that the posterior ligamentous complex (PLC) is intact. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate treatment recommendation?

. Posterior short-segment fusion
. Anterior corpectomy and plating
. Thoracolumbosacral orthosis (TLSO)
. Percutaneous kyphoplasty
. Laminectomy alone

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO)

Explanation

This patient has a TLICS score of 2 (Burst fracture = 2, Intact neurology = 0, Intact PLC = 0). A TLICS score of less than 4 implies the injury is mechanically stable enough for non-operative management with a TLSO brace.

Question 909

Topic: Thoracolumbar Spine & Deformity

In the evaluation of adult spinal deformity, assessing spinopelvic parameters is essential. Which of the following statements best describes pelvic incidence (PI)?

. It fluctuates significantly when the patient transitions from standing to sitting.
. It is calculated as the pelvic tilt minus the sacral slope.
. It is a fixed, position-independent morphological parameter of the pelvis.
. It progressively decreases in magnitude as the patient ages.
. It primarily measures the coronal balance of the lower spine.

Correct Answer & Explanation

. It is a fixed, position-independent morphological parameter of the pelvis.

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter specific to each individual and does not change with position. It is the sum of pelvic tilt (PT) and sacral slope (SS) (PI = PT + SS) and dictates the necessary lumbar lordosis for optimal sagittal balance.

Question 910

Topic: Thoracolumbar Spine & Deformity

A 12-year-old gymnast presents with lower back pain and is diagnosed with an L5-S1 isthmic spondylolisthesis. Her slip is currently measured at 30% (Grade II). Which of the following radiographic parameters indicates the highest risk for progression of the slip?

. Dysplastic sacral dome
. Low pelvic incidence
. Low slip angle
. Spina bifida occulta at L5
. Decreased sacral slope

Correct Answer & Explanation

. Dysplastic sacral dome

Explanation

Risk factors for the progression of a pediatric spondylolisthesis include young age, female sex, high slip grade (>50%), high slip angle (kyphotic L5-S1 angle), a high pelvic incidence, and dysplastic features such as doming of the sacrum or a trapezoidal L5. A dysplastic sacral dome directly decreases the bony restraint to anterior translation.

Question 911

Topic: Thoracolumbar Spine & Deformity
According to the Wiltse classification, a spondylolisthesis resulting from a stress fracture of the pars interarticularis is classified as which type?
. Type I (Dysplastic)
. Type II (Isthmic)
. Type III (Degenerative)
. Type IV (Traumatic)
. Type V (Pathologic)

Correct Answer & Explanation

. Type II (Isthmic)

Explanation

In the Wiltse classification of spondylolisthesis, Type II is Isthmic, which is caused by a defect in the pars interarticularis (subtype IIA is a stress fracture, IIB is an elongated but intact pars, and IIC is an acute fracture). Type I is dysplastic, Type III is degenerative, Type IV is traumatic (fracture other than pars), and Type V is pathologic.

Question 912

Topic: Thoracolumbar Spine & Deformity

A 15-year-old gymnast presents with chronic low back pain that is heavily exacerbated by lumbar extension. Radiographs show a Grade 1 isthmic spondylolisthesis at L5-S1. What is the defining anatomic defect associated with this specific type of spondylolisthesis?

. Hypoplasia of the pedicles
. Defect or stress fracture of the pars interarticularis
. Degeneration of the facet joints
. Congenital absence of the posterior elements
. Rupture of the ligamentum flavum

Correct Answer & Explanation

. Defect or stress fracture of the pars interarticularis

Explanation

Isthmic spondylolisthesis (Wiltse Type II) is caused by a defect (spondylolysis), elongation, or acute fracture of the pars interarticularis. It is particularly common in adolescent athletes who perform repetitive spinal hyperextension, such as gymnasts and football linemen.

Question 913

Topic: Thoracolumbar Spine & Deformity

A 25-year-old male falls from a height and sustains an L1 burst fracture. Neurological examination is completely normal. Radiographs and CT show 40% loss of anterior vertebral body height, 15 degrees of local kyphosis, and 30% canal compromise by a retropulsed bone fragment. According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is the most appropriate initial management?

. Anterior corpectomy and fusion
. Posterior short-segment pedicle screw fixation
. Posterior laminectomy without fusion
. Conservative management with a TLSO brace
. Combined anterior-posterior stabilization

Correct Answer & Explanation

. Conservative management with a TLSO brace

Explanation

The TLICS score assesses morphology (burst = 2 points), neurologic status (intact = 0 points), and posterior ligamentous complex (PLC) integrity (assumed intact in burst fractures without severe kyphosis = 0 points). A total score of 2 suggests non-operative management. A TLSO brace is the standard of care for neurologically intact patients with a mechanically stable burst fracture (TLICS < 4).

Question 914

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male sustains an L1 burst fracture. He is neurologically intact. MRI reveals an indeterminate status of the posterior ligamentous complex (PLC). Using the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the patient's calculated score, and what is the corresponding treatment recommendation?

. Score 2: Non-operative management
. Score 3: Non-operative management
. Score 4: Surgeon's preference (operative or non-operative)
. Score 5: Operative management
. Score 6: Operative management

Correct Answer & Explanation

. Score 4: Surgeon's preference (operative or non-operative)

Explanation

The TLICS score is calculated as follows: Morphology - Burst fracture = 2 points; Neurological status - Intact = 0 points; PLC status - Indeterminate = 2 points. Total = 4 points. A TLICS score of less than 4 recommends non-operative treatment, greater than 4 recommends operative treatment, and exactly 4 represents an equivocal case where either operative or non-operative management is acceptable based on surgeon preference.

Question 915

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female gymnast presents with progressive low back pain. Radiographs show a Grade 2 L5-S1 spondylolisthesis. MRI demonstrates an intact pars interarticularis but elongated pars and pedicles. According to the Wiltse classification, what type of spondylolisthesis does she have?
. Type I (Dysplastic)
. Type II (Isthmic)
. Type III (Degenerative)
. Type IV (Traumatic)
. Type V (Pathologic)

Correct Answer & Explanation

. Type I (Dysplastic)

Explanation

Wiltse Type I (Dysplastic) spondylolisthesis is due to congenital abnormalities of the upper sacrum or L5 arch leading to facet incompetence. The pars is often elongated but remains intact. Type II (Isthmic) involves a lytic defect or stress fracture of the pars interarticularis, which is more common in gymnasts, but the MRI specifically noted an intact pars in this scenario.

Question 916

Topic: Thoracolumbar Spine & Deformity

According to the Thoracolumbar Injury Classification and Severity Score (TLICS), which of the following morphologic injury patterns is assigned the highest point value?

. Compression fracture
. Burst fracture
. Translation/rotation injury
. Distraction injury
. Wedge fracture

Correct Answer & Explanation

. Distraction injury

Explanation

In the TLICS system for thoracolumbar trauma, points for morphology are assigned as follows: Compression fracture = 1 point; Burst fracture = 2 points; Translation/rotation = 3 points; Distraction = 4 points. Thus, distraction injuries are deemed the most unstable morphology.

Question 917

Topic: Thoracolumbar Spine & Deformity

A 14-year-old male presents for evaluation of scoliosis. He is tall and thin with a wingspan greater than his height, and hypermobile joints. A mutation in the FBN1 gene is suspected. Which associated ocular abnormality is most characteristic of this condition?

. Inferior lens dislocation
. Superior lens dislocation
. Blue sclera
. Retinitis pigmentosa
. Cataracts

Correct Answer & Explanation

. Superior lens dislocation

Explanation

The patient has Marfan syndrome, caused by an autosomal dominant mutation in the FBN1 gene (fibrillin-1). A classic ocular finding in Marfan syndrome is superior (upward) lens dislocation (ectopia lentis). By contrast, homocystinuria, which can present with a similar habitus, is typically associated with inferior (downward) lens dislocation.

Question 918

Topic: Thoracolumbar Spine & Deformity

A 10-year-old boy with cerebral palsy presents with a rapidly progressive thoracolumbar scoliosis measuring 80 degrees, causing significant trunk imbalance and difficulty with seating. He has a history of non-ambulatory status and recurrent respiratory infections. Which of the following is the primary indication for surgical intervention in this patient, beyond cosmetic concerns?

. Prevention of progression during adolescent growth spurt.
. Improvement of pulmonary function and prevention of restrictive lung disease.
. Management of intractable back pain.
. Restoration of ambulatory function.
. Correction of pelvic obliquity to improve sitting balance and prevent pressure sores.

Correct Answer & Explanation

. Correction of pelvic obliquity to improve sitting balance and prevent pressure sores.

Explanation

For non-ambulatory patients with neuromuscular scoliosis, the primary indication for surgical intervention is often to improve sitting balance, correct pelvic obliquity, and prevent pressure sores, thereby enhancing quality of life and facilitating care. While severe curves can lead to pulmonary compromise, surgical correction in non-ambulatory patients typically results in only modest improvements in pulmonary function, and preventing restrictive lung disease is a secondary goal compared to seating balance. Pain is less common in this population compared to idiopathic scoliosis. Restoration of ambulatory function is not an indication for surgery in a non-ambulatory patient. Preventing progression is a general indication, but for curves this severe, functional improvement takes precedence.

Question 919

Topic: Thoracolumbar Spine & Deformity

A 19-year-old female presents to the ED following a high-speed motor vehicle collision where she was wearing a lap-belt only. Radiographs demonstrate a horizontal fracture through the spinous process, pedicles, and vertebral body of L1. What associated injury must be actively excluded in this patient?

. Aortic dissection
. Pulmonary contusion
. Hollow viscus gastrointestinal injury
. Renal artery thrombosis
. Diaphragmatic rupture

Correct Answer & Explanation

. Hollow viscus gastrointestinal injury

Explanation

Chance fractures are flexion-distraction injuries commonly associated with lap-belt use in motor vehicle collisions. There is a high incidence (up to 50%) of associated intra-abdominal injuries, particularly hollow viscus ruptures, which must be carefully evaluated.

Question 920

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with progressive lower back pain. Radiographs demonstrate an L5-S1 isthmic spondylolisthesis (Grade 2). What is the primary anatomic abnormality responsible for this condition?

. Defect or stress fracture of the pars interarticularis
. Degeneration of the facet joints and ligamentum flavum hypertrophy
. Congenital pedicle elongation
. Sacral agenesis and pelvic ring instability
. Herniation of the L5-S1 intervertebral disc

Correct Answer & Explanation

. Defect or stress fracture of the pars interarticularis

Explanation

Isthmic spondylolisthesis is most commonly caused by a stress fracture or elongation of the pars interarticularis (spondylolysis), typically seen in adolescent athletes subject to repetitive spinal hyperextension (e.g., gymnasts, football linemen).

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