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Thoracolumbar Spine & Deformity MCQs

Practice Set 19 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 361

Topic: Thoracolumbar Spine & Deformity

A 16-year-old gymnast presents with progressive lower back pain and left leg pain. Imaging demonstrates a Grade II L5-S1 isthmic spondylolisthesis with bilateral pars interarticularis defects. If the patient has isolated left lower extremity radicular symptoms, which nerve root is most likely affected by the primary pathoanatomy of this condition?

. Exiting L4 root
. Traversing L4 root
. Exiting L5 root
. Traversing L5 root
. Traversing S1 root

Correct Answer & Explanation

. Exiting L5 root

Explanation

In isthmic spondylolisthesis at L5-S1, the defect is in the pars interarticularis of L5. The L5 nerve root exits the spinal canal through the L5-S1 neural foramen, passing directly inferior and anterior to the L5 pars. Hypertrophic fibrocartilaginous tissue (the 'Gill nodule') that forms at the site of the pars defect commonly compresses this exiting L5 nerve root in the foramen. This contrasts with degenerative spondylolisthesis (e.g., L4-L5), where central/lateral recess stenosis typically compresses the traversing root (L5).

Question 362

Topic: Thoracolumbar Spine & Deformity

A 12-year-old female gymnast complains of persistent lower back pain. Imaging demonstrates an L5-S1 isthmic spondylolisthesis with 35% slippage (Grade II). She has failed 6 months of physical therapy and bracing. What is the most appropriate surgical intervention?

. L4-S1 posterior spinal fusion with instrumentation
. L5-S1 in situ posterolateral fusion
. Anterior lumbar interbody fusion (ALIF) alone
. L5 laminectomy without fusion
. Lumbar epidural steroid injections

Correct Answer & Explanation

. L5-S1 in situ posterolateral fusion

Explanation

For pediatric patients with symptomatic low-grade (<50%) isthmic spondylolisthesis failing conservative management, an in situ L5-S1 posterolateral fusion is the gold standard. Decompression without fusion is contraindicated in children due to the high risk of further slippage.

Question 363

Topic: Thoracolumbar Spine & Deformity

A 35-year-old construction worker falls from a height and sustains an L1 burst fracture. In the Thoracolumbar Injury Classification and Severity (TLICS) score, which of the following parameters is assigned the highest individual point value?

. Fracture morphology (burst)
. Complete neurological deficit
. Disrupted posterior ligamentous complex (PLC)
. Loss of vertebral body height > 50%
. Kyphotic angulation > 30 degrees

Correct Answer & Explanation

. Disrupted posterior ligamentous complex (PLC)

Explanation

In the TLICS scoring system, a disrupted Posterior Ligamentous Complex (PLC) is assigned 3 points. This is the highest individual score for structural integrity, pushing the total score toward a surgical indication (total score > 4).

Question 364

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast presents with persistent low back pain. Radiographs reveal a Grade II isthmic spondylolisthesis at L5-S1. She has failed 6 months of conservative management including bracing and physical therapy. What is the recommended surgical intervention?

. L5 pars repair (Bucks procedure)
. L4-S1 posterolateral fusion
. L5-S1 in situ posterolateral fusion
. L5-S1 aggressive reduction and interbody fusion
. L5 laminectomy alone

Correct Answer & Explanation

. L5-S1 in situ posterolateral fusion

Explanation

For symptomatic Grade I or II isthmic spondylolisthesis that fails conservative treatment in adolescents, an in situ posterolateral fusion of L5-S1 is the gold standard. It offers excellent clinical outcomes without the high neurological risk associated with reduction.

Question 365

Topic: Thoracolumbar Spine & Deformity

A 13-year-old female gymnast presents with persistent lower back pain for 6 months. Lateral radiographs show a grade 1 isthmic spondylolisthesis at L5-S1. MRI demonstrates bilateral pars defects with prominent marrow edema on STIR sequences, but no central canal stenosis. She has failed 6 weeks of rest and NSAIDs. What is the most appropriate next step in management?

. L5-S1 posterior instrumented fusion
. Direct pars repair surgery
. Rigid TLSO bracing and restriction from gymnastics for an additional 3-6 months
. L5 laminectomy
. Epidural steroid injection

Correct Answer & Explanation

. Rigid TLSO bracing and restriction from gymnastics for an additional 3-6 months

Explanation

This patient has an acute/subacute isthmic spondylolisthesis (pars stress fracture), indicated by the marrow edema on STIR MRI. In young athletes with early/active pars defects and low-grade slips, the standard initial treatment is a prolonged period of rigid bracing (TLSO or antilordotic brace) and cessation of the offending sports activity for 3 to 6 months to allow for bony healing. Surgery is reserved for patients failing prolonged conservative care.

Question 366

Topic: Thoracolumbar Spine & Deformity

A 15-year-old male presents with postural thoracic back pain and a prominent thoracic kyphosis. Radiographs are obtained to evaluate for Scheuermann's disease. According to the Sorensen criteria, what radiographic finding is required to confirm the diagnosis?

. Anterior wedging > 5 degrees in at least 3 consecutive vertebrae
. Anterior wedging > 10 degrees in at least 2 consecutive vertebrae
. Schmorl's nodes in at least 4 contiguous vertebrae
. Thoracic kyphosis > 40 degrees with rigid apical rotation
. Disc space narrowing in 3 contiguous segments

Correct Answer & Explanation

. Anterior wedging > 5 degrees in at least 3 consecutive vertebrae

Explanation

The classic Sorensen criteria for Scheuermann's kyphosis require the presence of greater than 5 degrees of anterior wedging in at least three consecutive thoracic vertebrae. Associated findings often include Schmorl's nodes and endplate irregularities, but are not strictly required for the criteria.

Question 367

Topic: Thoracolumbar Spine & Deformity

A neurologically intact 40-year-old male sustains an L1 burst fracture after a fall. MRI confirms that the posterior ligamentous complex (PLC) is completely intact. According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is his total score and the recommended management?

. Score 2, Non-operative treatment
. Score 4, Operative treatment
. Score 4, Non-operative treatment
. Score 5, Operative treatment
. Score 7, Operative treatment

Correct Answer & Explanation

. Score 2, Non-operative treatment

Explanation

The TLICS assigns 2 points for a burst fracture morphology, 0 points for an intact PLC, and 0 points for intact neurologic status. A total score of 3 or less indicates non-operative management is recommended.

Question 368

Topic: Thoracolumbar Spine & Deformity

When placing a standard anatomic lumbar pedicle screw at the L4 level, what is the most widely accepted surface landmark for the starting point?

. The junction of the inferior articular process and the pars interarticularis
. The intersection of a line bisecting the transverse process and the vertical line through the lateral border of the superior articular process
. Just medial to the lateral border of the inferior articular process
. The exact geometric center of the vertebral body laterally
. The absolute tip of the transverse process

Correct Answer & Explanation

. The intersection of a line bisecting the transverse process and the vertical line through the lateral border of the superior articular process

Explanation

The anatomic starting point for a lumbar pedicle screw is located at the intersection of a horizontal line bisecting the transverse process and a vertical line plumb with the lateral border of the superior articular process (facet joint).

Question 369

Topic: Thoracolumbar Spine & Deformity

A 16-year-old male presents with thoracic back pain and a rigid kyphotic deformity. Lateral radiographs demonstrate anterior wedging of the T7, T8, and T9 vertebral bodies. What is the minimum degree of wedging required in each of these adjacent vertebrae to confirm the diagnosis of classic Scheuermann's disease?

. 3 degrees
. 5 degrees
. 10 degrees
. 15 degrees
. 20 degrees

Correct Answer & Explanation

. 5 degrees

Explanation

The Sorensen criteria for classic Scheuermann's kyphosis require anterior wedging of greater than 5 degrees in at least three consecutive vertebrae. It is also associated with irregular endplates and Schmorl's nodes.

Question 370

Topic: Thoracolumbar Spine & Deformity

A 12-year-old female presents with a high-grade (Meyerding Grade IV) L5-S1 isthmic spondylolisthesis. She has severe hamstring tightness and an abnormal gait, but is neurologically intact. During surgical intervention, an attempt is made to fully reduce the spondylolisthesis prior to fusion. Which nerve root is at the greatest risk of injury during this reduction maneuver?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L5

Explanation

Reduction of high-grade L5-S1 spondylolisthesis places the L5 nerve root at significant risk of traction injury as it stretches over the sacral ala. Partial reduction or in situ fusion is often utilized to minimize this risk.

Question 371

Topic: Thoracolumbar Spine & Deformity

An adult patient with severe sagittal imbalance secondary to flatback syndrome is evaluated for corrective surgery. On standing lateral radiographs, the patient's lumbar lordosis is significantly reduced. What is the primary pelvic compensatory mechanism the patient will use to maintain an upright posture and keep their gaze horizontal?

. Pelvic anteversion (decreased Pelvic Tilt)
. Pelvic retroversion (increased Pelvic Tilt)
. Decreased Pelvic Incidence
. Increased Sacral Slope
. Hip extension

Correct Answer & Explanation

. Pelvic retroversion (increased Pelvic Tilt)

Explanation

In the setting of a loss of lumbar lordosis (sagittal positive imbalance), the body compensates by rotating the pelvis posteriorly (pelvic retroversion), which radiographically presents as an increased Pelvic Tilt (PT) and a decreased Sacral Slope (SS). Pelvic Incidence (PI) remains constant.

Question 372

Topic: Thoracolumbar Spine & Deformity

A 45-year-old male presents after a motor vehicle accident with an L1 burst fracture. Neurological examination is completely normal. CT and MRI show a burst fracture with retropulsion, intact posterior ligamentous complex, and no epidural hematoma. What is his Thoracolumbar Injury Classification and Severity (TLICS) score, and what is the recommended management?

. Score 2, nonoperative management
. Score 4, operative management
. Score 5, operative management
. Score 3, nonoperative or operative management
. Score 1, nonoperative management

Correct Answer & Explanation

. Score 2, nonoperative management

Explanation

The TLICS score for this patient is 2: morphology is burst (2 points), neurological status is intact (0 points), and the posterior ligamentous complex is intact (0 points). A score of 3 or less is a strong indication for nonoperative management.

Question 373

Topic: Thoracolumbar Spine & Deformity

In a patient presenting with L4-L5 degenerative spondylolisthesis, which facet joint orientation is most strongly associated with the pathogenesis of this condition?

. Coronal orientation
. Sagittal orientation
. Axial orientation
. Hypertrophied uncinate process
. Hypoplastic superior articular process

Correct Answer & Explanation

. Sagittal orientation

Explanation

Degenerative spondylolisthesis is most commonly associated with a sagittal orientation of the facet joints (facet tropism). Sagittally oriented facets are less capable of resisting anterior shear forces, leading to progressive slip over time.

Question 374

Topic: Thoracolumbar Spine & Deformity

In the Thoracolumbar Injury Classification and Severity (TLICS) score, how many points are assigned to a frank disruption of the posterior ligamentous complex (PLC), and what is the surgical implication if a patient's total score is 5?

. 2 points; nonoperative treatment is recommended
. 3 points; nonoperative treatment is recommended
. 3 points; surgical stabilization is recommended
. 4 points; surgical stabilization is recommended
. 2 points; surgical stabilization is recommended

Correct Answer & Explanation

. 3 points; surgical stabilization is recommended

Explanation

In the TLICS system, PLC disruption is assigned 3 points (suspected/indeterminate is 2 points, intact is 0). A total TLICS score of 4 can be treated operatively or nonoperatively (surgeon's preference), while a total score of >= 5 is an indication for surgical stabilization.

Question 375

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast presents with 3 months of activity-related low back pain. Radiographs are normal. MRI of the lumbar spine reveals hyperintensity on STIR imaging in the L5 pars interarticularis bilaterally, without a visible fracture line on T1-weighted images. What is the most appropriate initial management?

. Immediate pars repair surgery
. Corticosteroid injection into the pars defect
. Rigid TLSO bracing and cessation of hyperextension activities
. Observation and continuation of sports as tolerated
. Bilateral L5 transforaminal epidural steroid injections

Correct Answer & Explanation

. Rigid TLSO bracing and cessation of hyperextension activities

Explanation

The patient has an acute stress reaction of the pars interarticularis (early spondylolysis) identified by edema on STIR MRI without a complete fracture. The initial management consists of cessation of offending activities (hyperextension) and bracing (TLSO) to allow the stress reaction to heal and prevent progression to a complete nonunion.

Question 376

Topic: Thoracolumbar Spine & Deformity
To achieve optimal postoperative sagittal balance in a patient undergoing surgical correction for adult lumbar degenerative scoliosis, the lumbar lordosis (LL) should be matched to the patient's pelvic incidence (PI). According to the Schwab criteria, what is the widely accepted target formula for this relationship?
. LL = PI ± 10 degrees
. LL = PI + 20 degrees
. LL = PT + SS
. LL = PI × 2
. LL = SS - 10 degrees

Correct Answer & Explanation

. LL = PI ± 10 degrees

Explanation

The SRS-Schwab adult spinal deformity classification identifies key radiographic sagittal parameters associated with health-related quality of life. The ideal target is a mismatch of less than 10 degrees between Pelvic Incidence (PI) and Lumbar Lordosis (LL), expressed as PI - LL < 10 degrees (or LL = PI ± 10 degrees). This restores harmonic sagittal alignment and minimizes the risk of adjacent segment disease and hardware failure.

Question 377

Topic: Thoracolumbar Spine & Deformity
A 35-year-old male sustains an L1 burst fracture. He is neurologically intact. MRI demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is his total score and the generally recommended management?
. Score 2: Nonoperative management
. Score 3: Surgeon's discretion
. Score 4: Operative management
. Score 5: Operative management
. Score 7: Operative management

Correct Answer & Explanation

. Score 2: Nonoperative management

Explanation

The TLICS system scores injuries based on morphology, neurologic status, and posterior ligamentous complex (PLC) integrity. A burst fracture morphology scores 2 points. Intact neurology scores 0 points. An intact PLC scores 0 points. The total score is 2. A TLICS score of ≤ 3 indicates nonoperative management, a score of 4 is surgeon discretion, and a score ≥ 5 indicates operative management.

Question 378

Topic: Thoracolumbar Spine & Deformity
According to the Wiltse classification of spondylolisthesis, a Type II (isthmic) slip is further subdivided based on the mechanism of pars interarticularis failure. Which of the following describes the pathophysiology defining a Type IIA slip?
. Congenital dysplasia of the L5-S1 facet joints
. Fatigue (stress) fracture of the pars interarticularis
. Elongation of an intact pars interarticularis due to repeated microfracture healing
. Acute traumatic fracture of the pars interarticularis
. Degenerative instability secondary to facet arthritis without a pars defect

Correct Answer & Explanation

. Fatigue (stress) fracture of the pars interarticularis

Explanation

The Wiltse classification defines Type II as Isthmic spondylolisthesis. It is subdivided into Type IIA (fatigue/stress fracture of the pars), Type IIB (elongated but intact pars, resulting from repeated microfracture and healing), and Type IIC (acute traumatic fracture of the pars). Type I is dysplastic, and Type III is degenerative.

Question 379

Topic: Thoracolumbar Spine & Deformity

A 35-year-old female falls from a height. Imaging reveals an L1 burst fracture. She is neurologically intact. MRI demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is her total score, and what is the recommended management?

. Score 2, Nonoperative management
. Score 4, Operative management
. Score 4, Surgeon's choice
. Score 5, Operative management
. Score 2, Operative management

Correct Answer & Explanation

. Score 2, Nonoperative management

Explanation

The TLICS system assigns points for morphology, neurologic status, and PLC integrity. Burst fracture = 2 points. Neurologically intact = 0 points. PLC intact = 0 points. Total score = 2. A score of <= 3 recommends nonoperative management. A score of 4 is surgeon's choice. A score >= 5 strongly recommends operative management.

Question 380

Topic: Thoracolumbar Spine & Deformity
According to the Wiltse classification of spondylolisthesis, a vertebral slip occurring secondary to a fatigue 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

Type II (Isthmic) spondylolisthesis is caused by a defect in the pars interarticularis, typically due to a stress/fatigue fracture. Type I is dysplastic, Type III is degenerative, Type IV is traumatic (fracture other than pars), and Type V is pathologic.

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