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Thoracolumbar Spine & Deformity MCQs

Practice Set 18 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 341

Topic: Thoracolumbar Spine & Deformity

A 4-year-old girl with early-onset idiopathic scoliosis and a 65-degree curve undergoes implantation of magnetically controlled growing rods (MCGR). What is the primary advantage of this technology compared to traditional growing rods (TGR)?

. It provides a definitive rigid fusion at an earlier age.
. It significantly reduces the number of repeated surgical procedures for lengthenings.
. It allows for continuous real-time distraction over months.
. It entirely eliminates the risk of proximal junctional kyphosis.
. It is safe for use in patients requiring serial MRI imaging.

Correct Answer & Explanation

. It provides a definitive rigid fusion at an earlier age.

Explanation

The primary advantage of magnetically controlled growing rods (MCGR, e.g., MAGEC) over traditional growing rods is the ability to perform lengthenings non-invasively in an outpatient clinic using an external remote control. This avoids the need for repetitive operative lengthenings every 6 months under general anesthesia, thereby reducing surgical risks, infection rates, and psychological trauma to the child. MCGRs do not eliminate PJK and are generally MRI conditional or contraindicated due to the internal magnet.

Question 342

Topic: Thoracolumbar Spine & Deformity

A 65-year-old woman undergoes corrective surgery for severe adult spinal deformity. To minimize the risk of adjacent segment disease, proximal junctional kyphosis, and mechanical failure, the pelvic incidence minus lumbar lordosis (PI-LL) should ideally be corrected to within what range?

. ± 5 degrees
. ± 10 degrees
. ± 20 degrees
. ± 30 degrees
. ± 45 degrees

Correct Answer & Explanation

. ± 5 degrees

Explanation

According to the Schwab criteria for adult spinal deformity, adequate sagittal balance correction requires a PI-LL mismatch of less than 10 degrees (ideally ± 10 degrees) to optimize outcomes and minimize mechanical complications.

Question 343

Topic: Thoracolumbar Spine & Deformity

A 45-year-old man falls from a height. CT shows an L1 burst fracture with 40% loss of height and 30% canal compromise. He is neurologically intact. MRI confirms the posterior ligamentous complex (PLC) is intact. What is his Thoracolumbar Injury Classification and Severity (TLICS) score, and what is the recommended treatment?

. TLICS 2, non-operative management
. TLICS 4, surgical management
. TLICS 5, surgical management
. TLICS 2, surgical management
. TLICS 4, non-operative management

Correct Answer & Explanation

. TLICS 2, non-operative management

Explanation

The TLICS score is 2: 2 points for a burst fracture mechanism, 0 points for intact neurology, and 0 points for an intact PLC. A score of 3 or less is an indication for non-operative management (e.g., bracing).

Question 344

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman presents with severe flatback deformity and sagittal imbalance following a prior lumbar fusion from L3 to S1. Her pelvic incidence (PI) is 55 degrees. Standing full-length radiographs reveal a current lumbar lordosis (LL) of 15 degrees and a sagittal vertical axis (SVA) of +12 cm. To achieve optimal sagittal balance, what should be the target postoperative lumbar lordosis?

. 15 degrees
. 30 degrees
. 45 degrees
. 65 degrees
. 80 degrees

Correct Answer & Explanation

. 15 degrees

Explanation

In adult spinal deformity, the formula PI = PT + SS is critical, and the goal for lumbar lordosis (LL) is to be within 10 degrees of the pelvic incidence (PI). For a PI of 55 degrees, the target LL should be approximately 45 to 65 degrees.

Question 345

Topic: Thoracolumbar Spine & Deformity

A 15-year-old male with a history of back pain presents with bilateral lower extremity radicular pain. Radiographs reveal a Grade IV isthmic spondylolisthesis at L5-S1. During surgical reduction and fusion, the patient is at highest risk for iatrogenic injury to which of the following nerve roots?

. L4
. L5
. S1
. S2
. S3

Correct Answer & Explanation

. L4

Explanation

In high-grade L5-S1 isthmic spondylolisthesis, the L5 nerve root is stretched over the sacral ala. Reduction maneuvers place the L5 nerve root at significant risk for stretch injury or traction neuropraxia.

Question 346

Topic: Thoracolumbar Spine & Deformity

A 16-year-old male gymnast complains of insidious onset, mechanical lower back pain. Radiographs are normal. A T2-weighted STIR MRI of the lumbar spine reveals bilateral high signal intensity in the L5 pars interarticularis. There is no spondylolisthesis. What is the most appropriate initial management?

. In situ posterolateral fusion of L5-S1
. Direct pars repair with pedicle screws and hooks
. Epidural steroid injection
. Rigid antilordotic bracing and activity restriction
. Diagnostic nerve root block

Correct Answer & Explanation

. In situ posterolateral fusion of L5-S1

Explanation

High signal intensity on STIR MRI indicates an acute pars stress reaction or early stress fracture (spondylolysis) with bone marrow edema. The standard treatment for an acute/active pars defect is rigid bracing and cessation of the offending sport.

Question 347

Topic: Thoracolumbar Spine & Deformity

A 35-year-old woman falls from a height and sustains a T12 burst fracture. She is neurologically intact. MRI demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is her total score and the recommended management?

. Score 2; nonoperative management
. Score 4; operative management
. Score 5; operative management
. Score 7; operative management
. Score 3; nonoperative or operative management

Correct Answer & Explanation

. Score 2; nonoperative management

Explanation

According to the TLICS system, a burst fracture morphology receives 2 points, an intact neurologic status receives 0 points, and an intact PLC receives 0 points. A total score of 2 indicates nonoperative management.

Question 348

Topic: Thoracolumbar Spine & Deformity

A 15-year-old boy presents with progressive back pain and a prominent thoracic kyphosis. Standing lateral radiographs reveal anterior wedging of multiple consecutive thoracic vertebrae. According to Sorensen's criteria, what is the strict radiographic definition of classic Scheuermann's disease?

. Anterior wedging of at least 5 degrees in 2 or more consecutive vertebrae
. Anterior wedging of at least 5 degrees in 3 or more consecutive vertebrae
. Anterior wedging of at least 10 degrees in 2 or more consecutive vertebrae
. Anterior wedging of at least 10 degrees in 3 or more consecutive vertebrae
. Anterior wedging of at least 15 degrees in 3 or more consecutive vertebrae

Correct Answer & Explanation

. Anterior wedging of at least 5 degrees in 2 or more consecutive vertebrae

Explanation

Sorensen's criteria for classic Scheuermann's kyphosis require anterior wedging of at least 5 degrees in 3 or more consecutive vertebrae. Other common findings include Schmorl's nodes and narrowed disc spaces.

Question 349

Topic: Thoracolumbar Spine & Deformity

A 16-year-old female gymnast complains of mechanical low back pain for 6 months. Imaging reveals a bilateral L5 pars defect with a Grade I anterior slip of L5 on S1. Conservative treatment has failed. Which of the following pelvic parameters is the strongest predictor for progression of the spondylolisthesis?

. Low pelvic incidence
. High pelvic incidence
. Low sacral slope
. High pelvic tilt
. Negative sagittal vertical axis

Correct Answer & Explanation

. Low pelvic incidence

Explanation

A high pelvic incidence increases the shear stress at the lumbosacral junction. It is considered a strong anatomical predictor for the development and progression of L5-S1 isthmic spondylolisthesis.

Question 350

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast presents with progressive lower back pain and is diagnosed with an L5-S1 isthmic spondylolisthesis. Which of the following statements regarding her spino-pelvic parameters is most accurate concerning the etiology of her condition?

. Pelvic incidence is generally lower than the normal population.
. High pelvic incidence is a predisposing factor due to increased shear forces at L5-S1.
. Pelvic tilt typically decreases to compensate for the sagittal imbalance.
. Sacral slope is typically decreased in patients with high-grade isthmic spondylolisthesis.
. Pelvic incidence changes significantly after skeletal maturity.

Correct Answer & Explanation

. Pelvic incidence is generally lower than the normal population.

Explanation

High pelvic incidence (PI = Pelvic Tilt + Sacral Slope) is strongly correlated with the development of isthmic spondylolisthesis. A higher PI leads to an increased sacral slope, which in turn increases the anterior shear forces acting across the pars interarticularis at the L5-S1 junction. Pelvic incidence is considered a fixed morphological parameter after skeletal maturity.

Question 351

Topic: Thoracolumbar Spine & Deformity
A 35-year-old female falls from a horse and sustains a T12 burst fracture. On CT, there is 40% canal compromise, but the posterior ligamentous complex (PLC) is intact. She has 5/5 strength in all lower extremity myotomes, normal sensation, and intact bowel/bladder function. What is her Thoracolumbar Injury Classification and Severity (TLICS) score, and what is the recommended treatment based on this score?
. Score 2; Nonoperative treatment with a TLSO brace
. Score 4; Operative or Nonoperative treatment
. Score 5; Operative fixation
. Score 7; Emergent operative decompression and fixation
. Score 3; Nonoperative treatment

Correct Answer & Explanation

. Score 2; Nonoperative treatment with a TLSO brace

Explanation

The Thoracolumbar Injury Classification and Severity (TLICS) score determines treatment for thoracolumbar fractures based on three categories. 1) Morphology: Burst fracture = 2 points. 2) Neurological status: Intact = 0 points. 3) Posterior ligamentous complex (PLC) integrity: Intact = 0 points. The total score is 2. A score of ≤3 indicates nonoperative management (e.g., TLSO brace). A score of 4 is indeterminate, and ≥5 suggests operative management.

Question 352

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female competitive gymnast presents with progressive low back pain and hamstring tightness. Radiographs demonstrate a grade II L5-S1 isthmic spondylolisthesis. She has failed 6 months of comprehensive nonoperative management including physical therapy and bracing. What is the most appropriate surgical intervention?

. L5-S1 anterior lumbar interbody fusion (ALIF) alone
. L5 laminectomy without fusion
. L5-S1 posterior instrumented fusion
. L4-S1 posterior instrumented fusion
. L5-S1 artificial disc replacement

Correct Answer & Explanation

. L5-S1 anterior lumbar interbody fusion (ALIF) alone

Explanation

For a pediatric or adolescent patient with a symptomatic low-grade (Grade I or II) isthmic spondylolisthesis that has failed conservative treatment, an L5-S1 posterolateral fusion (with or without instrumentation) is the gold standard surgical treatment. Laminectomy alone is contraindicated in the pediatric population as it increases instability and the risk of further slip progression. ALIF alone or disc replacement is not indicated for this pathology in adolescents.

Question 353

Topic: Thoracolumbar Spine & Deformity

A 45-year-old male sustains an L1 burst fracture after falling from a height. Neurological examination reveals normal motor and sensory function in the bilateral lower extremities, and normal rectal tone. CT imaging demonstrates a 40% loss of anterior vertebral body height, 15 degrees of local kyphosis, and 25% spinal canal compromise. MRI confirms that the posterior ligamentous complex (PLC) is completely intact. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the generally recommended management?

. Score 2, nonoperative management
. Score 4, operative management
. Score 5, operative management
. Score 2, operative management
. Score 4, nonoperative management

Correct Answer & Explanation

. Score 2, nonoperative management

Explanation

The Thoracolumbar Injury Classification and Severity (TLICS) system is based on three categories: injury morphology, neurological status, and integrity of the posterior ligamentous complex (PLC). For this patient: Morphology is a burst fracture (2 points). Neurological status is intact (0 points). PLC is intact (0 points). The total score is 2. A TLICS score of 3 or less indicates nonoperative management (e.g., bracing or observation), a score of 4 is indeterminate (surgeon preference), and a score of 5 or more indicates operative intervention.

Question 354

Topic: Thoracolumbar Spine & Deformity

A 14-year-old boy presents with progressive thoracic back pain and a visible rounding of his upper back. Standing lateral radiographs are obtained to evaluate for Scheuermann kyphosis. According to the classic Sorensen criteria, radiographic confirmation of this diagnosis requires anterior wedging of at least what magnitude, involving how many consecutive vertebrae?

. 5 degrees in at least 3 consecutive vertebrae
. 10 degrees in at least 2 consecutive vertebrae
. 10 degrees in at least 3 consecutive vertebrae
. 15 degrees in at least 2 consecutive vertebrae
. 5 degrees in at least 4 consecutive vertebrae

Correct Answer & Explanation

. 5 degrees in at least 3 consecutive vertebrae

Explanation

The Sorensen criteria for diagnosing Scheuermann kyphosis define the condition radiographically by the presence of anterior wedging of 5 degrees or more in at least 3 consecutive thoracic vertebrae.

Question 355

Topic: Thoracolumbar Spine & Deformity

A 40-year-old male falls from a height of 10 feet, sustaining an L1 burst fracture. He is neurologically intact on presentation. A subsequent 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 generally recommended management?

. Score 2, non-operative management
. Score 3, non-operative management
. Score 4, operative or non-operative management
. Score 5, operative management
. Score 6, operative management

Correct Answer & Explanation

. Score 2, non-operative management

Explanation

The TLICS system assigns points based on three categories: injury morphology, neurologic status, and integrity of the posterior ligamentous complex (PLC). Burst fracture morphology = 2 points. Neurologically intact = 0 points. Intact PLC = 0 points. Total score = 2. A score of 3 or less is an indication for non-operative management, a score of 4 is equivocal, and 5 or more indicates operative intervention.

Question 356

Topic: Thoracolumbar Spine & Deformity

A 30-year-old male falls from a roof and sustains a T12 burst fracture. He is neurologically intact with no focal deficits. An MRI is obtained, which demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and recommended treatment?

. Score 4; surgical intervention recommended
. Score 2; non-operative treatment recommended
. Score 5; surgical intervention recommended
. Score 2; surgical intervention recommended
. Score 7; surgical intervention recommended

Correct Answer & Explanation

. Score 2; non-operative treatment recommended

Explanation

The TLICS score is calculated based on three categories: injury morphology, neurologic status, and posterior ligamentous complex (PLC) integrity. A burst fracture morphology receives 2 points. Intact neurologic status receives 0 points. An intact PLC receives 0 points. The total score is 2. A TLICS score of less than 4 implies non-operative management is recommended.

Question 357

Topic: Thoracolumbar Spine & Deformity

A 30-year-old male sustains a fall from a height. Radiographs and CT show an L1 burst fracture. His neurologic examination is completely normal. MRI reveals a complete disruption of the posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the recommended treatment?

. Score 3; non-operative treatment
. Score 4; treatment is at the surgeon's discretion
. Score 5; operative treatment
. Score 6; operative treatment
. Score 7; operative treatment

Correct Answer & Explanation

. Score 5; operative treatment

Explanation

The TLICS score is calculated based on three categories: 1) Morphology: Burst fracture = 2 points. 2) Neurologic status: Intact = 0 points. 3) Posterior ligamentous complex (PLC) integrity: Disrupted = 3 points. Total score = 2 + 0 + 3 = 5. A TLICS score of > 4 indicates instability, and operative intervention is strictly recommended.

Question 358

Topic: Thoracolumbar Spine & Deformity

A 24-year-old female presents after a high-speed motor vehicle collision. She was wearing a lap-only seatbelt. Imaging reveals a flexion-distraction injury (Chance fracture) at L2. She is neurologically intact. Which of the following is the most commonly associated concomitant injury in this patient population?

. Aortic transection
. Solid organ laceration
. Hollow viscus injury
. Pulmonary contusion
. Pelvic ring disruption

Correct Answer & Explanation

. Hollow viscus injury

Explanation

Chance fractures are flexion-distraction injuries commonly associated with lap seatbelts. Up to 50% of these patients have concomitant intra-abdominal injuries, with hollow viscus (especially small bowel) perforations being the most common.

Question 359

Topic: Thoracolumbar Spine & Deformity

A 22-year-old male presents after a high-speed motor vehicle collision where he was wearing a lap belt. Radiographs and CT demonstrate a flexion-distraction injury (Chance fracture) extending through the L2 vertebral body. Which associated injury must be ruled out due to its high incidence in this scenario?

. Aortic transection
. Renal artery thrombosis
. Intra-abdominal hollow viscus injury
. Diaphragmatic rupture
. Splenic laceration

Correct Answer & Explanation

. Intra-abdominal hollow viscus injury

Explanation

Chance fractures (flexion-distraction injuries) commonly occur in lap-belt restrained passengers during severe decelerations. They are highly associated with intra-abdominal injuries (up to 50% incidence), particularly hollow viscus injuries like bowel perforations, necessitating urgent general surgery evaluation.

Question 360

Topic: Thoracolumbar Spine & Deformity

A 65-year-old woman is scheduled for a total hip arthroplasty. Standing and sitting lateral spinopelvic radiographs reveal a stiff lumbar spine with a pelvic tilt change of 5 degrees between standing and sitting, and a significantly decreased standing sacral slope. What is the most appropriate modification in acetabular cup positioning to minimize the risk of dislocation?

. Decrease anteversion and decrease abduction
. Increase anteversion and increase abduction
. Decrease anteversion and increase abduction
. Maintain standard safe zone positioning (15 degrees anteversion, 40 degrees abduction)
. Increase anteversion only while significantly decreasing abduction

Correct Answer & Explanation

. Increase anteversion and increase abduction

Explanation

A stiff lumbar spine (change in pelvic tilt < 10 degrees) combined with a decreased standing sacral slope indicates a 'flatback' deformity where the pelvis is already retroverted and does not retrovert further normally upon sitting. This puts the patient at a high risk for anterior impingement and subsequent posterior dislocation during sitting. To compensate for the lack of dynamic functional pelvic retroversion in flexion, the cup should be placed in more anteversion and slightly more inclination (abduction).

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