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Thoracolumbar Spine & Deformity MCQs

Practice Set 1 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 1

Topic: Thoracolumbar Spine & Deformity

A 16-year-old gymnast presents with chronic low back pain exacerbated by extension. Radiographs are normal, but an MRI shows bone marrow edema in the L5 pars interarticularis without a clear fracture line. What is the most appropriate initial management?

. Immediate surgical pars repair
. Rigid TLSO bracing and restriction from sports for 3 months
. Continuation of gymnastics with NSAIDs
. Lumbar epidural steroid injections
. L5-S1 instrumented fusion

Correct Answer & Explanation

. Rigid TLSO bracing and restriction from sports for 3 months

Explanation

An early pars stress reaction (edema on MRI without a frank fracture) has a high potential for healing. Management includes activity restriction and rigid antilordotic bracing until pain resolves.

Question 2

Topic: Thoracolumbar Spine & Deformity

Which type of scoliosis is most common in adolescents?

. Congenital scoliosis
. Neuromuscular scoliosis
. Idiopathic scoliosis
. Degenerative scoliosis
. Post-traumatic scoliosis

Correct Answer & Explanation

. Idiopathic scoliosis

Explanation

Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis, usually developing around puberty with no clear cause.

Question 3

Topic: Thoracolumbar Spine & Deformity

A 14-year-old male with an L5-S1 isthmic spondylolisthesis presents with persistent low back pain. Which of the following radiographic parameters is most highly associated with the risk of slip progression?

. High pelvic incidence
. Low sacral slope
. High pelvic tilt
. Presence of a spina bifida occulta
. Lumbar hypolordosis

Correct Answer & Explanation

. High pelvic incidence

Explanation

High pelvic incidence is a primary biomechanical risk factor for the development and progression of isthmic spondylolisthesis. It results in increased shear forces across the lumbosacral junction.

Question 4

Topic: Thoracolumbar Spine & Deformity

According to the Sorensen criteria, classic Scheuermann's kyphosis is defined radiographically by a thoracic kyphosis greater than 40 degrees accompanied by which of the following?

. Anterior wedging of at least 5 degrees in 2 consecutive vertebrae
. Anterior wedging of at least 5 degrees in 3 consecutive vertebrae
. Anterior wedging of at least 10 degrees in 2 consecutive vertebrae
. Schmorl's nodes in at least 3 consecutive vertebrae
. Endplate irregularities in 4 consecutive vertebrae

Correct Answer & Explanation

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

Explanation

The Sorensen criteria strictly define classic Scheuermann's disease as thoracic kyphosis > 40 degrees with anterior wedging of at least 5 degrees in three or more consecutive vertebrae.

Question 5

Topic: Thoracolumbar Spine & Deformity

According to the Sorensen criteria, what is the strict radiographic requirement for the diagnosis of classic Scheuermann's kyphosis?

. Anterior wedging of greater than 5 degrees in at least two consecutive vertebrae.
. Anterior wedging of greater than 5 degrees in at least three consecutive vertebrae.
. Anterior wedging of greater than 10 degrees in at least two consecutive vertebrae.
. Anterior wedging of greater than 10 degrees in at least three consecutive vertebrae.
. Presence of multiple Schmorl's nodes with endplate irregularities only.

Correct Answer & Explanation

. Anterior wedging of greater than 10 degrees in at least three consecutive vertebrae.

Explanation

Sorensen classically defined Scheuermann's disease as a thoracic kyphosis featuring greater than 5 degrees of anterior wedging in at least three consecutive vertebrae. Endplate irregularities and Schmorl's nodes are supportive but not sufficient alone for the classic definition.

Question 6

Topic: Thoracolumbar Spine & Deformity

What percentage of women with osteoporotic fractures develop kyphosis:

. 10%
. 15%
. 25%
. 30%
. 60%

Correct Answer & Explanation

. 10%

Explanation

Approximately 15% of women with osteoporotic fractures develop kyphosis. This is often due to the presence of multiple vertebral compression fractures with segmental kyphosis at each level.

Question 7

Topic: Thoracolumbar Spine & Deformity

Which of the following describes the widely accepted radiographic diagnostic criteria for Scheuermann's kyphosis?

. Anterior wedging of >3 degrees in 5 consecutive vertebrae
. Anterior wedging of >5 degrees in 3 consecutive vertebrae
. Anterior wedging of >10 degrees in 2 consecutive vertebrae
. Lateral wedging of >5 degrees in 3 consecutive vertebrae
. The presence of Schmorl's nodes in any 3 vertebrae regardless of wedging

Correct Answer & Explanation

. Anterior wedging of >5 degrees in 3 consecutive vertebrae

Explanation

The classic Sorensen criteria for diagnosing Scheuermann's disease require radiographic evidence of anterior vertebral body wedging of greater than 5 degrees in at least three consecutive vertebrae.

Question 8

Topic: Thoracolumbar Spine & Deformity

According to the Denis three-column classification of thoracolumbar fractures, which structures comprise the middle column?

. Anterior longitudinal ligament and anterior half of the vertebral body
. Posterior half of the vertebral body, posterior half of the annulus fibrosus, and PLL
. Facet joints, ligamentum flavum, and posterior neural arch
. Spinous processes and interspinous ligaments
. Pedicles, laminae, and pars interarticularis

Correct Answer & Explanation

. Posterior half of the vertebral body, posterior half of the annulus fibrosus, and PLL

Explanation

The Denis middle column consists of the posterior half of the vertebral body, the posterior half of the annulus fibrosus, and the posterior longitudinal ligament (PLL). Disruption of this column distinguishes a burst fracture from a simple compression fracture.

Question 9

Topic: Thoracolumbar Spine & Deformity
Using the Thoracolumbar Injury Classification and Severity (TLICS) score, which of the following clinical scenarios most definitively indicates the need for surgical intervention (score > 4)?
. Compression fracture (morphology) with an intact posterior ligamentous complex (PLC)
. Burst fracture with an intact PLC and no neurologic deficit
. Translational/rotational injury with a complete neurologic deficit
. Isolated transverse process fractures
. Isolated spinous process fracture

Correct Answer & Explanation

. Translational/rotational injury with a complete neurologic deficit

Explanation

In the TLICS system, a translational/rotational injury yields 3 points, a complete neuro deficit yields 2 points, and a ruptured PLC yields 3 points. A total score greater than 4 is a strict indication for surgical stabilization.

Question 10

Topic: Thoracolumbar Spine & Deformity

A 30-year-old male falls from a height and sustains an L1 burst fracture. Neurological examination is completely normal. MRI demonstrates an intact posterior ligamentous complex (PLC). What is his Thoracolumbar Injury Classification and Severity (TLICS) score, and what is the recommended treatment?

. Score 2; Non-operative management
. Score 4; Operative management
. Score 5; Operative management
. Score 2; Operative management
. Score 3; Conservative or operative management

Correct Answer & Explanation

. Score 2; Non-operative management

Explanation

The TLICS score is 2: morphology is burst (2 points), neurological status is intact (0 points), and PLC is intact (0 points). A score of 3 or less indicates non-operative management.

Question 11

Topic: Thoracolumbar Spine & Deformity

A 22-year-old female presents after a high-speed motor vehicle collision where she was wearing a lap belt. She sustains a flexion-distraction injury (Chance fracture) at L2. Which of the following associated injuries must be highly suspected and ruled out?

. Aortic dissection
. Hollow viscus injury
. Renal artery thrombosis
. Diaphragmatic rupture
. Pelvic ring disruption

Correct Answer & Explanation

. Hollow viscus injury

Explanation

Chance fractures (flexion-distraction injuries) in the setting of lap belt use are highly associated with intra-abdominal injuries. Hollow viscus (bowel) injuries occur in up to 50% of these cases.

Question 12

Topic: Thoracolumbar Spine & Deformity

Which of the following patient profiles is most strongly associated with the development of degenerative lumbar spondylolisthesis?

. Teenage male athlete
. Young female with a pars interarticularis defect
. Caucasian female over 50 years of age
. Male over 60 years of age with DISH
. Any patient with prior lumbar fusion

Correct Answer & Explanation

. Caucasian female over 50 years of age

Explanation

Degenerative lumbar spondylolisthesis occurs most frequently at the L4-L5 level. It is classically seen in females over the age of 50, particularly those with more sagittally oriented facet joints.

Question 13

Topic: Thoracolumbar Spine & Deformity

Cortical bone trajectory (CBT) pedicle screws are increasingly used in minimally invasive lumbar fusions. Which of the following best describes the starting point and trajectory of a CBT screw compared to a traditional pedicle screw?

. More lateral starting point, trajectory directed medially and caudad
. More lateral starting point, trajectory directed medially and cephalad
. More medial starting point, trajectory directed laterally and cephalad
. More medial starting point, trajectory directed laterally and caudad
. Identical starting point, trajectory directed strictly cephalad

Correct Answer & Explanation

. More lateral starting point, trajectory directed medially and cephalad

Explanation

CBT screws are inserted with a medial-to-lateral and caudad-to-cephalad trajectory, starting at the junction of the pars interarticularis and superior articular process. This maximizes engagement with high-density cortical bone, increasing pullout strength.

Question 14

Topic: Thoracolumbar Spine & Deformity

Review the provided imaging.

In managing a patient with symptomatic L4-L5 degenerative spondylolisthesis, which of the following is a proven advantage of utilizing a minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) over an open approach?

. Reduced incidence of adjacent segment disease
. Superior restoration of coronal balance
. Decreased postoperative narcotic use and shorter hospital stay
. Lower rate of long-term pseudarthrosis
. Decreased intraoperative fluoroscopy time

Correct Answer & Explanation

. Decreased postoperative narcotic use and shorter hospital stay

Explanation

Extensive literature comparing MIS TLIF to open TLIF for degenerative spondylolisthesis demonstrates that MIS approaches lead to less intraoperative blood loss, decreased postoperative narcotic consumption, and a shorter hospital length of stay. Long-term fusion rates and ASD incidence remain similar.

Question 15

Topic: Thoracolumbar Spine & Deformity

Cortical bone trajectory (CBT) screws have gained popularity in minimally invasive lumbar fusions. Which of the following best describes the entry point and trajectory of a CBT pedicle screw compared to a traditional pedicle screw?

. Lateral to medial, aimed caudally
. Lateral to medial, aimed parallel to the endplate
. Medial to lateral, aimed cephalad
. Medial to lateral, aimed caudally
. Directly posterior to anterior, avoiding the pars

Correct Answer & Explanation

. Lateral to medial, aimed caudally

Explanation

The CBT screw entry point is in the pars interarticularis, starting medially and aiming laterally and cephalad. This maximizes contact with higher-density cortical bone, increasing pullout strength.

Question 16

Topic: Thoracolumbar Spine & Deformity

For a patient with an L5-S1 isthmic spondylolisthesis and significant loss of segmental lordosis, an Anterior Lumbar Interbody Fusion (ALIF) may be preferred over an MIS TLIF. What is the primary biomechanical advantage of ALIF at this specific level?

. Higher rate of successful posterior decompression
. Reduced risk of retrograde ejaculation
. Superior ability to restore segmental sagittal lordosis
. Avoidance of major vascular structures
. Lower risk of postoperative abdominal hernia

Correct Answer & Explanation

. Higher rate of successful posterior decompression

Explanation

ALIF at L5-S1 allows for the placement of a large, highly lordotic cage and release of the anterior longitudinal ligament (ALL), providing far superior restoration of segmental lordosis compared to a posterior/transforaminal approach.

Question 17

Topic: Thoracolumbar Spine & Deformity

During a minimally invasive TLIF using a tubular retractor system, the initial docking site for the first dilator is typically the:

. Base of the spinous process
. Spinolaminar junction
. Pars interarticularis and facet joint
. Transverse process
. Pedicle base

Correct Answer & Explanation

. Pars interarticularis and facet joint

Explanation

The tubular retractor is typically docked on the pars interarticularis and the ipsilateral facet joint complex. This provides direct access for the facetectomy and subsequent transforaminal approach to the disc space.

Question 18

Topic: Thoracolumbar Spine & Deformity

In cortical bone trajectory (CBT) pedicle screws used for minimally invasive fusions, the screw trajectory is typically described as:

. Lateral to medial, cephalad to caudad
. Medial to lateral, caudad to cephalad
. Lateral to medial, parallel to the endplate
. Medial to lateral, cephalad to caudad
. Directly anterior through the pars interarticularis

Correct Answer & Explanation

. Medial to lateral, caudad to cephalad

Explanation

CBT screws are inserted with a medial to lateral and caudad to cephalad trajectory. This maximizes thread purchase in high-density cortical bone, increasing pullout strength, especially in osteoporotic bone.

Question 19

Topic: Thoracolumbar Spine & Deformity

A major disadvantage of the minimally invasive posterior lumbar interbody fusion (MIS PLIF) approach compared to MIS TLIF is:

. Lower fusion rates
. Inability to perform bilateral decompression
. Higher risk of thecal sac and traversing nerve root injury due to greater retraction
. Increased disruption of the lateral pars interarticularis
. Requirement for an anterior abdominal incision

Correct Answer & Explanation

. Higher risk of thecal sac and traversing nerve root injury due to greater retraction

Explanation

MIS PLIF requires bilateral laminotomies and significant medial retraction of the thecal sac and traversing nerve roots to insert the interbody cages. This increases the risk of dural tears and neurologic injury compared to the unilateral transforaminal approach of MIS TLIF.

Question 20

Topic: Thoracolumbar Spine & Deformity

In Cortical Bone Trajectory (CBT) screw fixation, often utilized in minimally invasive lumbar surgeries, the pedicle screw path is fundamentally directed:

. Lateral to medial and cephalad to caudal
. Medial to lateral and caudal to cephalad
. Lateral to medial and caudal to cephalad
. Medial to lateral and cephalad to caudal
. Directly anterior without sagittal angulation

Correct Answer & Explanation

. Medial to lateral and caudal to cephalad

Explanation

CBT screws maximize cortical bone contact by starting medially at the pars interarticularis and directed laterally and cephalad. This trajectory allows for a smaller midline incision and increased pullout strength.

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