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6. Spine MCQs

Practice Set 77 of 379

This practice set contains high-yield board review questions covering key concepts in 6. Spine. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1521

Topic: 6. Spine

A 16-year-old male presents with a 60-degree right thoracic scoliosis. He is skeletally mature with a Risser sign of 5. The curve has shown minimal progression (1 degree per year) since skeletal maturity. He reports significant cosmetic concerns due to rib prominence. Based on the provided treatment guidelines, what is the most appropriate management option?

. A. Continued observation with annual radiographs.
. B. Initiation of bracing to prevent further progression.
. C. Surgical correction with posterior spinal fusion.
. D. Anterior spinal fusion due to the large curve magnitude.
. E. Physical therapy and chiropractic adjustments.

Correct Answer & Explanation

. C. Surgical correction with posterior spinal fusion.

Explanation

Correct Answer: CExplanation:The text states that surgery is 'Usually reserved for curves with a magnitude > 50.' This patient has a 60-degree curve, which clearly exceeds this threshold. Additionally, 'unacceptable deformity' is listed as an indication for surgery, and the patient reports significant cosmetic concerns due to rib prominence, which is a common associated problem with scoliosis. Given the large, structural curve, surgical correction is the most appropriate management.A. Continued observation with annual radiographs.While progression slows after skeletal maturity, a 60-degree curve is already severe and warrants intervention, especially with cosmetic concerns. Observation alone is not sufficient for curves of this magnitude.B. Initiation of bracing to prevent further progression.Bracing is typically used for progressive curves between 25-40 degrees in skeletally immature patients to prevent progression. It is not effective for curves over 40-50 degrees or in skeletally mature individuals.D. Anterior spinal fusion due to the large curve magnitude.While anterior approaches can be considered for thoracolumbar curves, the text notes a recent trend towards posterior approach with 'third-generation' instrumentation (segmental pedicle screws). The choice of anterior vs. posterior is secondary to the indication for surgery itself, and for a thoracic curve, posterior is often preferred.E. Physical therapy and chiropractic adjustments.These modalities are not effective in correcting or preventing the progression of structural scoliosis of this magnitude.

Question 1522

Topic: 6. Spine

A 13-year-old girl presents with a 28-degree right thoracic scoliosis. Her Risser sign is 2, and she is 6 months post-menarche. Her parents are concerned about the curve's progression. During the examination, the Adam's forward bend test is performed. What is the primary purpose of the Adam's forward bend test in the assessment of scoliosis?

. A. To determine the patient's skeletal maturity.
. B. To measure the Cobb angle accurately.
. C. To assess the flexibility of the spinal curve.
. D. To detect rotational deformity and rib prominence.
. E. To identify underlying intraspinal anomalies.

Correct Answer & Explanation

. D. To detect rotational deformity and rib prominence.

Explanation

Correct Answer: DExplanation:The Adam's forward bend test is a clinical screening tool primarily used to detect rotational deformity of the trunk, which manifests as a rib hump or prominence in the thoracic spine or a lumbar prominence. This prominence is a key indicator of the three-dimensional nature of scoliosis, where lateral curvature is accompanied by vertebral rotation.A. To determine the patient's skeletal maturity.Skeletal maturity is assessed using radiographic indicators like the Risser sign, not the Adam's forward bend test.B. To measure the Cobb angle accurately.The Cobb angle is a radiographic measurement, not determined by physical examination.C. To assess the flexibility of the spinal curve.Curve flexibility is typically assessed with lateral bending radiographs, not the Adam's forward bend test.E. To identify underlying intraspinal anomalies.Intraspinal anomalies are typically identified through MRI, especially in atypical curves or those with neurological signs. The Adam's test does not directly detect these.

Question 1523

Topic: Thoracolumbar Spine & Deformity

A 4-year-old child is diagnosed with a progressive idiopathic scoliosis. The curve measures 40 degrees. The parents are counseled on the potential long-term complications. Which of the following is the most significant long-term risk specifically associated with this type of scoliosis, as highlighted in the case?

. A. Increased risk of severe back pain in adulthood.
. B. Development of significant leg length discrepancy.
. C. Progressive cardiorespiratory compromise leading to decreased life expectancy.
. D. Higher incidence of spondylolisthesis in later life.
. E. Increased likelihood of neurological deficits due to spinal cord compression.

Correct Answer & Explanation

. C. Progressive cardiorespiratory compromise leading to decreased life expectancy.

Explanation

Correct Answer: CExplanation:The patient is 4 years old with idiopathic scoliosis, which falls under the 'Early-onset scoliosis' category (onset before age 7). The text explicitly states for early-onset scoliosis: 'The developing heart and lungs may be affected by the scoliosis. Cardiorespiratory compromise may result from a progressive curve resulting in decreased life expectancy.' This is the most significant and unique long-term risk highlighted for this specific age group.A. Increased risk of severe back pain in adulthood.While scoliosis patients can experience back pain, the text notes that scoliosis is 'not typically thought of as a painful condition,' and severe pain may indicate an underlying cause. Cardiorespiratory compromise is a more specific and severe risk for early-onset scoliosis.B. Development of significant leg length discrepancy.Leg length discrepancy can mimic scoliosis but is not a direct long-term complication of idiopathic scoliosis itself.D. Higher incidence of spondylolisthesis in later life.Spondylolisthesis is a separate spinal condition and not a direct long-term complication of idiopathic scoliosis.E. Increased likelihood of neurological deficits due to spinal cord compression.While severe curves can theoretically lead to neurological issues, this is less common in idiopathic scoliosis compared to congenital scoliosis with intraspinal anomalies. Cardiorespiratory compromise is the primary concern for early-onset idiopathic scoliosis.

Question 1524

Topic: Thoracolumbar Spine & Deformity

A 68-year-old female presents with adult spinal deformity and severe flatback syndrome. Preoperative radiographic evaluation reveals a Pelvic Incidence (PI) of 58 degrees. To optimize her postoperative sagittal balance and minimize the risk of adjacent segment disease or proximal junctional kyphosis, what should be the target postoperative Lumbar Lordosis (LL)?

. 28 degrees
. 38 degrees
. 48 degrees
. 58 degrees
. 78 degrees

Correct Answer & Explanation

. 58 degrees

Explanation

In adult spinal deformity surgery, the target lumbar lordosis should generally be within 9-10 degrees of the patient's pelvic incidence (PI). Thus, for a PI of 58, a target LL of approximately 58 (ideal range 48-68) minimizes the risk of sagittal imbalance and subsequent complications.

Question 1525

Topic: Thoracolumbar Spine & Deformity

A 65-year-old male with adult spinal deformity presents with severe low back pain and forward truncal tilt. Radiographs demonstrate a pelvic incidence (PI) of 65 degrees. To achieve optimal sagittal balance postoperatively, what should be the surgical target for his lumbar lordosis (LL)?

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

Correct Answer & Explanation

. 55 degrees

Explanation

Optimal sagittal alignment is achieved when the patient's lumbar lordosis matches their intrinsic pelvic incidence. The widely accepted target rule is PI minus LL should be less than or equal to 10 degrees; thus, a PI of 65 requires an LL of at least 55 degrees.

Question 1526

Topic: Thoracolumbar Spine & Deformity

In a patient with an L5-S1 isthmic spondylolisthesis who presents with severe radiating leg pain, which nerve root is most commonly compressed, and what is the primary anatomic location of this compression?

. L4 nerve root in the lateral recess
. L5 nerve root in the neural foramen
. S1 nerve root in the lateral recess
. S1 nerve root in the neural foramen
. L5 nerve root in the central canal

Correct Answer & Explanation

. L5 nerve root in the neural foramen

Explanation

In isthmic spondylolisthesis at L5-S1, the exiting L5 nerve root is most commonly compressed within the neural foramen. The compression is typically caused by the hypertrophic fibrocartilaginous pseudarthrosis tissue at the pars interarticularis defect.

Question 1527

Topic: 6. Spine

An 11-year-old boy with Duchenne muscular dystrophy (DMD) presents with a rapidly progressive 45-degree thoracolumbar neuromuscular scoliosis. His forced vital capacity (FVC) has recently declined to 40% of predicted. What is the most appropriate management?

. Rigid TLSO bracing to delay surgical intervention
. Vertical Expandable Prosthetic Titanium Rib (VEPTR) placement
. Posterior spinal fusion from the upper thoracic spine to the pelvis
. Observation until the curve reaches 60 degrees
. Selective anterior thoracic spinal fusion

Correct Answer & Explanation

. Posterior spinal fusion from the upper thoracic spine to the pelvis

Explanation

Bracing is contraindicated in DMD as it is ineffective for curve control and worsens restrictive pulmonary disease. Posterior spinal fusion to the pelvis is indicated for curves >20-30 degrees while pulmonary function (FVC >30%) is still adequate to tolerate surgery.

Question 1528

Topic: Thoracolumbar Spine & Deformity

A 16-year-old male undergoes posterior spinal fusion with instrumental reduction for a high-grade (Meyerding Grade IV) L5-S1 isthmic spondylolisthesis. Postoperatively, he exhibits unilateral foot drop and weakness in great toe extension. Injury to which neural structure is the most likely cause?

. L4 nerve root
. L5 nerve root
. S1 nerve root
. S2 nerve root
. Sciatic nerve trunk

Correct Answer & Explanation

. L5 nerve root

Explanation

Complete reduction of high-grade lumbosacral spondylolisthesis significantly stretches the L5 nerve root, which is tethered over the sacral ala. This iatrogenic traction injury classically presents as an L5 palsy with foot drop and EHL weakness.

Question 1529

Topic: 6. Spine

Proximal junctional kyphosis (PJK) is a recognized complication following long posterior spinal fusions. According to standard radiographic definitions, between which two anatomical landmarks is the proximal junctional sagittal angle measured to diagnose PJK?

. Lower endplate of UIV to upper endplate of UIV+1
. Lower endplate of UIV to upper endplate of UIV+2
. Upper endplate of UIV to lower endplate of UIV+1
. Lower endplate of UIV-1 to upper endplate of UIV+2
. Lower endplate of UIV to upper endplate of UIV+3

Correct Answer & Explanation

. Lower endplate of UIV to upper endplate of UIV+2

Explanation

PJK is classically defined radiographically by a proximal junctional sagittal angle of 10 degrees or more. This angle is measured between the lower endplate of the upper instrumented vertebra (UIV) and the upper endplate of the vertebra two levels above (UIV+2).

Question 1530

Topic: Thoracolumbar Spine & Deformity

A 70-year-old female with adult degenerative scoliosis and progressive sagittal imbalance presents with a measured pelvic tilt (PT) of 35 degrees. What compensatory mechanism does this elevated pelvic tilt primarily indicate?

. Pelvic anteversion to maintain horizontal gaze
. Pelvic retroversion to compensate for the loss of lumbar lordosis
. Hip flexion to increase the sagittal vertical axis
. Knee extension to reduce energy expenditure
. Ankle plantarflexion to shift the center of gravity anteriorly

Correct Answer & Explanation

. Pelvic retroversion to compensate for the loss of lumbar lordosis

Explanation

An abnormally high pelvic tilt indicates pelvic retroversion. In the setting of severe loss of lumbar lordosis (positive sagittal imbalance), the pelvis retroverts as a compensatory mechanism to shift the body's center of gravity posteriorly over the hips and maintain upright posture.

Question 1531

Topic: Thoracolumbar Spine & Deformity

A 15-year-old male presents with rigid thoracic kyphosis. Radiographs demonstrate Schmorl nodes, endplate irregularities, and anterior vertebral wedging. To meet Sorensen's strict criteria for the diagnosis of Scheuermann's kyphosis, what is the minimum degree of wedging required, and across how many consecutive vertebrae?

. At least 5 degrees across 2 consecutive vertebrae
. At least 5 degrees across 3 consecutive vertebrae
. At least 10 degrees across 2 consecutive vertebrae
. At least 10 degrees across 3 consecutive vertebrae
. At least 15 degrees across 4 consecutive vertebrae

Correct Answer & Explanation

. At least 5 degrees across 3 consecutive vertebrae

Explanation

Sorensen's classical radiographic criteria for Scheuermann's kyphosis require anterior wedging of at least 5 degrees in three or more consecutive vertebrae. Associated findings include Schmorl nodes, endplate irregularities, and a kyphosis >45 degrees.

Question 1532

Topic: 6. Spine

In the evaluation of infantile idiopathic scoliosis, which of the following radiographic parameters is the most reliable predictor of curve progression versus spontaneous resolution?

. Mehta's Rib-Vertebra Angle Difference (RVAD)
. Risser sign
. Pelvic incidence to lumbar lordosis mismatch
. T1 pelvic angle
. Apical vertebral translation >2 cm

Correct Answer & Explanation

. Mehta's Rib-Vertebra Angle Difference (RVAD)

Explanation

Mehta's Rib-Vertebra Angle Difference (RVAD) is the most predictive measure in infantile idiopathic scoliosis. An RVAD greater than 20 degrees strongly predicts curve progression, whereas an RVAD less than 20 degrees generally indicates the curve will resolve spontaneously.

Question 1533

Topic: 6. Spine

A 58-year-old male with L4-L5 degenerative spondylolisthesis (Grade I) and symptomatic neurogenic claudication asks about long-term outcomes. According to the Spine Patient Outcomes Research Trial (SPORT), what is the expected long-term outcome of surgical decompression with fusion versus non-operative treatment?

. Surgery offers no advantage over non-operative care at 4 years.
. Surgery maintains significantly better outcomes in pain and function at 4 to 8 years.
. Non-operative care results in fewer total complications and equivalent pain relief.
. Decompression alone is statistically superior to decompression with fusion.
. Fusion without decompression yields the highest patient satisfaction scores.

Correct Answer & Explanation

. Surgery maintains significantly better outcomes in pain and function at 4 to 8 years.

Explanation

The SPORT trial for degenerative spondylolisthesis demonstrated that patients treated with surgical decompression and fusion had significantly greater improvements in pain and physical function compared to the non-operative cohort, and these benefits were maintained at the 8-year follow-up.

Question 1534

Topic: Thoracolumbar Spine & Deformity

A 65-year-old female undergoes surgical correction for adult spinal deformity. Postoperative goals for sagittal realignment are critical for optimizing health-related quality of life (HRQOL) outcomes. Which of the following sets of spinopelvic parameters represents the recognized target thresholds for optimal surgical correction?

. Sagittal vertical axis (SVA) < 5 cm, Pelvic tilt (PT) < 20 degrees, and PI-LL mismatch < 10 degrees
. Sagittal vertical axis (SVA) < 10 cm, Pelvic tilt (PT) < 30 degrees, and PI-LL mismatch < 20 degrees
. Sagittal vertical axis (SVA) < 5 cm, Pelvic tilt (PT) < 10 degrees, and PI-LL mismatch < 5 degrees
. Sagittal vertical axis (SVA) < 2 cm, Pelvic tilt (PT) < 15 degrees, and PI-LL mismatch < 15 degrees
. Sagittal vertical axis (SVA) < 8 cm, Pelvic tilt (PT) < 25 degrees, and PI-LL mismatch < 10 degrees

Correct Answer & Explanation

. Sagittal vertical axis (SVA) < 5 cm, Pelvic tilt (PT) < 20 degrees, and PI-LL mismatch < 10 degrees

Explanation

The Schwab criteria for optimal sagittal realignment in adult spinal deformity include an SVA < 5 cm, PT < 20 degrees, and a mismatch between pelvic incidence and lumbar lordosis (PI-LL) of < 10 degrees. Achieving these parameters is strongly correlated with improved patient-reported outcomes.

Question 1535

Topic: 6. Spine

A 2-year-old child presents with a noticeable spinal curve. Radiographs confirm congenital scoliosis. Which of the following anatomic anomaly patterns carries the highest risk for rapid curve progression and typically requires early prophylactic surgical fusion?

. Fully segmented hemivertebra
. Unilateral unsegmented bar with a contralateral hemivertebra
. Incarcerated hemivertebra
. Block vertebra
. Bilateral failure of segmentation

Correct Answer & Explanation

. Unilateral unsegmented bar with a contralateral hemivertebra

Explanation

A unilateral unsegmented bar with a contralateral hemivertebra has a 100% chance of progression and represents the highest risk pattern in congenital scoliosis. This deformity creates an extreme growth imbalance, necessitating early surgical intervention.

Question 1536

Topic: 6. Spine

A 16-year-old male with Grade IV isthmic spondylolisthesis at L5-S1 undergoes a posterior spinal fusion with instrumental reduction. Postoperatively, he exhibits a new neurological deficit. Based on the mechanics of high-grade slip reduction, which of the following deficits is most likely to be observed?

. Weakness in hip flexion
. Weakness in knee extension
. Weakness in ankle plantarflexion
. Weakness in extensor hallucis longus
. Bowel and bladder incontinence

Correct Answer & Explanation

. Weakness in extensor hallucis longus

Explanation

Reduction of high-grade L5-S1 spondylolisthesis significantly stretches the L5 nerve root due to the altered anatomy and corrective forces. This most commonly presents as an L5 radiculopathy, characterized by weakness in ankle dorsiflexion and the extensor hallucis longus.

Question 1537

Topic: Thoracolumbar Spine & Deformity

A 6-month-old infant is diagnosed with infantile idiopathic scoliosis. Measurement of the rib-vertebral angle difference (RVAD) of Mehta is obtained. Which of the following RVAD values and phase descriptions is most strongly predictive of curve progression?

. RVAD < 10 degrees, Phase 1
. RVAD > 10 degrees, Phase 1
. RVAD < 20 degrees, Phase 2
. RVAD > 20 degrees, Phase 2
. RVAD > 20 degrees, Phase 1

Correct Answer & Explanation

. RVAD > 20 degrees, Phase 2

Explanation

An RVAD greater than 20 degrees is highly predictive of curve progression in infantile idiopathic scoliosis. Phase 2 (where the rib head overlaps the vertebral body) combined with an RVAD > 20 degrees strongly indicates a progressive curve requiring intervention.

Question 1538

Topic: 6. Spine

A 14-year-old male with Duchenne Muscular Dystrophy (DMD) has a progressive neuromuscular scoliosis of 45 degrees. He is wheelchair-bound. At what forced vital capacity (FVC) threshold does the perioperative mortality risk significantly increase, making spinal fusion highly perilous?

. FVC < 80% of predicted
. FVC < 60% of predicted
. FVC < 50% of predicted
. FVC < 30% of predicted
. FVC < 15% of predicted

Correct Answer & Explanation

. FVC < 30% of predicted

Explanation

In patients with Duchenne Muscular Dystrophy, a forced vital capacity (FVC) below 30% of predicted marks a significantly higher risk for perioperative pulmonary complications and mortality. Surgery is typically recommended before the curve exceeds 30-40 degrees and while FVC remains above this threshold.

Question 1539

Topic: Thoracolumbar Spine & Deformity
A 10-year-old girl presents with back pain and a severe grade III spondylolisthesis at L5-S1. Radiographs demonstrate a high slip angle, a dome-shaped sacrum, and a trapezoidal L5 vertebral body. The pars interarticularis is elongated but intact. According to the Wiltse classification, which type of spondylolisthesis does this patient have?
. Type I (Dysplastic)
. Type II (Isthmic)
. Type III (Degenerative)
. Type IV (Traumatic)
. Type V (Pathologic)

Correct Answer & Explanation

. Type I (Dysplastic)

Explanation

Type I (Dysplastic) spondylolisthesis is characterized by congenital anomalies of the upper sacrum or L5 neural arch, such as a dome-shaped sacrum and trapezoidal L5. It often presents in children with a high slip angle and an intact but elongated pars, carrying a high risk of progression.

Question 1540

Topic: 6. Spine

A 15-year-old male complains of mid-back pain and progressive rounding of his shoulders. Standing lateral radiographs reveal a thoracic kyphosis of 65 degrees. Which of the following radiographic criteria is definitively required to confirm a diagnosis of Scheuermann's kyphosis?

. Anterior wedging of at least 5 degrees in one vertebra
. Anterior wedging of at least 5 degrees in three consecutive vertebrae
. Thoracic kyphosis greater than 45 degrees with Schmorl's nodes
. Loss of disc height in the mid-thoracic spine
. Irregular vertebral endplates in five consecutive vertebrae

Correct Answer & Explanation

. Anterior wedging of at least 5 degrees in three consecutive vertebrae

Explanation

The classic Sorensen criteria for diagnosing Scheuermann's kyphosis require anterior wedging of greater than or equal to 5 degrees in at least three consecutive vertebrae. Associated findings often include Schmorl's nodes and irregular endplates.

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