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Thoracolumbar Spine & Deformity MCQs

Practice Set 5 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 81

Topic: Thoracolumbar Spine & Deformity
Which patient is at the lowest risk for progression of spondylolisthesis?
. A 45-year-old man with grade II isthmic spondylolisthesis at L5-S1.
. A 5-year-old girl with grade I dysplastic spondylolisthesis at L5-S1.
. A 25-year-old man with a grade I isthmic spondylolisthesis at L4-5.
. A 16-year-old boy with Grade III isthmic spondylolisthesis at L5-S1.
. A 12-year-old girl with Grade II isthmic spondylolisthesis at L5-S1.

Correct Answer & Explanation

. A 45-year-old man with grade II isthmic spondylolisthesis at L5-S1.

Explanation

Young age, dysplastic spondylolisthesis, and spondylolisthesis above L5-S1 are all risk factors for progression. Adults with isthmic spondylolisthesis at L5-S1 (85% of cases) are at a low risk for progression of the slippage.

Question 82

Topic: Thoracolumbar Spine & Deformity

A 30-year-old immigrant presents with an 8-month history of middle back pain, weight loss, and progressive lower extremity weakness. Imaging shows severe thoracic kyphosis, destruction of T7 and T8 vertebral bodies, and a large calcified paraspinal abscess. What is the most appropriate surgical approach?

. Posterior laminectomy without fusion
. Posterior decompression and pedicle screw fixation only
. Anterior decompression, debridement, and strut graft reconstruction
. Minimally invasive percutaneous drainage of the abscess
. Posterolateral transpedicular biopsy without decompression

Correct Answer & Explanation

. Anterior decompression, debridement, and strut graft reconstruction

Explanation

In advanced tuberculous spondylitis (Pott's disease) presenting with progressive neurologic deficit and significant anterior column destruction (kyphosis), anterior decompression and structural grafting (the Hong Kong procedure) is the gold standard surgical treatment.

Question 83

Topic: Thoracolumbar Spine & Deformity

An absolute indication for surgical management of thoracolumbar burst fractures is:

. Canal compromise greater than 10%
. Canal compromise greater than 30%
. Kyphotic deformity greater than 10%
. Kyphotic deformity greater than 30%
. Progressive neurologic deficit

Correct Answer & Explanation

. Progressive neurologic deficit

Explanation

Patients with a neurologic deficit or a progressive neurologic deficit should undergo operative decompression. C ontroversy exists as to the amount of kyphosis and canal compression that is considered acceptable. Support can be found in the literature for both operative and nonoperative management of neurologically intact burst fractures. Each patient must be evaluated on a case by case basis and followed closely after injury.

Question 84

Topic: Thoracolumbar Spine & Deformity

The classic Sorensen radiographic criteria for the diagnosis of Scheuermann's kyphosis require which of the following findings?

. Anterior wedging of greater than 5 degrees in at least 3 sequential vertebrae
. Anterior wedging of greater than 10 degrees in at least 2 sequential vertebrae
. Schmorl's nodes in at least 4 contiguous vertebrae
. Endplate irregularities in 3 non-sequential vertebrae
. Thoracic kyphosis greater than 40 degrees with neutral wedging

Correct Answer & Explanation

. Anterior wedging of greater than 5 degrees in at least 3 sequential vertebrae

Explanation

Sorensen criteria define Scheuermann's kyphosis strictly as anterior wedging of greater than 5 degrees in at least three consecutive vertebral bodies. Endplate irregularities and Schmorl's nodes are supportive findings but are not required for diagnosis.

Question 85

Topic: Thoracolumbar Spine & Deformity

A 25-year-old male sustains a T12 Chance fracture following a high-speed motor vehicle collision while wearing a lap belt. What associated injury must be urgently ruled out during his initial trauma evaluation?

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

Correct Answer & Explanation

. Intra-abdominal hollow viscus injury

Explanation

Chance fractures are flexion-distraction injuries highly associated with lap seatbelt use. There is a high incidence (up to 50%) of concomitant intra-abdominal injuries, particularly hollow viscus ruptures, which must be immediately excluded.

Question 86

Topic: Thoracolumbar Spine & Deformity

An 18-year-old man comes to the office with a grade IV isthmic spondylolisthesis and severe left lower extremity discomfort. Which imaging study would best help identify the site of potential nerve root compression:

. Computed tomography scan
. Magnetic resonance imaging (MRI) scan
. Plain myelography
. Bone scan
. Positron emission tomography (PET)

Correct Answer & Explanation

. Magnetic resonance imaging (MRI) scan

Explanation

An MRI scan would be the imaging study of choice to best identify the site of nerve root compression because it provides parasagittal views that can help determine the degree of narrowing of the neural foramina. Plain myelography may not accurately identify lateral recess compression. A C T scan would produce images perpendicular to the plane of nerve root compression. Bone scan and PET scan would be of little or no help in identifying nerve root compression.

Question 87

Topic: Thoracolumbar Spine & Deformity

This radiograph shows a grade I spondylolisthesis of L5 on S1. This is due to a defect in what anatomical area:

. Superior articular process
. Inferior articular process
. Pars interarticularis
. Pedicle
. Lamina

Correct Answer & Explanation

. Pars interarticularis

Explanation

The anatomical region involved in a spondylolisthesis is the pars interarticularis that is located between the superior and inferior articular processes and is a high stress area of relatively thinner bone.

Question 88

Topic: Thoracolumbar Spine & Deformity

A 16-year-old football lineman develops unrelenting low back pain for the past 3 months. Based on the magnetic resonance image shown, the next step in the management of this patient is:

. Fusion in situ
. Epidural injection therapy
. Excision of a herniated disk
. Restriction of the exacerbating activity
. Observation

Correct Answer & Explanation

. Restriction of the exacerbating activity

Explanation

This patient has a grade I-II spondylolisthesis of L5 on S1. The initial management should include restriction of physical activity. Once the symptoms abate, the athlete can return to the sport. If symptoms return, other interventions are indicated including possible brace wear.C orrect Answer: Restriction of the exacerbating activity

Question 89

Topic: Thoracolumbar Spine & Deformity

A 35-year-old woman presents with severe back pain. Radiographic evaluation reveals a thoracic curve of 70° and a loss of thoracic kyphosis. Surgery is recommended to correct the deformity. Which of the following tests must be ordered as part of the preoperative evaluation:

. Electrocardiogram (ECG)
. Pulmonary function tests
. Electromyelogram (EMG)
. Chest radiograph
. Somatosensory evoked potentials (SSEP)

Correct Answer & Explanation

. Pulmonary function tests

Explanation

Thoracic curves greater than 65° may affect pulmonary function, especially when they are combined with thoracic lordosis. This patient displays a thoracic curve of 70° and a loss of the normal thoracic kyphosis; therefore, pulmonary function tests are part of the routine evaluation.

Question 90

Topic: Thoracolumbar Spine & Deformity
When evaluating a patient with spondylolisthesis, the Meyerding classification is commonly used to grade the severity of the slip. A Meyerding Grade III slip corresponds to what percentage of anterior translation of the superior vertebral body over the inferior one?
. 1-25%
. 26-50%
. 51-75%
. 76-100%
. Complete ptosis (>100%)

Correct Answer & Explanation

. 51-75%

Explanation

The Meyerding classification grades spondylolisthesis based on the percentage of slip: Grade I (1-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (>100%, spondyloptosis).

Question 91

Topic: Thoracolumbar Spine & Deformity

What is the primary anatomical defect responsible for the development of an isthmic spondylolisthesis?

. Congenital dysplasia of the sacral facets
. Degenerative hypertrophy of the ligamentum flavum
. A defect or stress fracture in the pars interarticularis
. Elongation of the vertebral pedicles
. A defect in the anterior longitudinal ligament

Correct Answer & Explanation

. A defect or stress fracture in the pars interarticularis

Explanation

Isthmic spondylolisthesis (Type II) is characterized by a defect or stress fracture in the pars interarticularis. This allows the anterior column to slip forward while the posterior elements remain behind.

Question 92

Topic: Thoracolumbar Spine & Deformity



On oblique lumbar radiographs, the posterior elements resemble a "Scotty dog". In the context of isthmic spondylolisthesis, a defect is often seen as a "collar" around the dog's neck. Which anatomical structure corresponds to the neck of the Scotty dog?

. Pedicle
. Superior articular process
. Pars interarticularis
. Transverse process
. Inferior articular process

Correct Answer & Explanation

. Pars interarticularis

Explanation

On an oblique lumbar radiograph, the "neck" of the Scotty dog represents the pars interarticularis. A radiolucent line or "collar" indicates a pars defect (spondylolysis).

Question 93

Topic: Thoracolumbar Spine & Deformity
According to the Wiltse classification of spondylolisthesis, a slip that occurs secondary to an elongation of the pars interarticularis without a frank defect 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

Elongation of the pars interarticularis without a frank defect is classified as a Wiltse Type IIb (Isthmic) spondylolisthesis. Type II is divided into lytic (IIa), elongated (IIb), and acute fracture (IIc).

Question 94

Topic: Thoracolumbar Spine & Deformity

A 15-year-old male gymnast presents with a 4-month history of localized low back pain exacerbated by extension. Oblique radiographs of the lumbar spine are obtained.

A defect in which anatomical structure represents the collar on the "Scotty dog"?

. Pedicle
. Transverse process
. Pars interarticularis
. Superior articular facet
. Spinous process

Correct Answer & Explanation

. Pars interarticularis

Explanation

The 'collar' on the Scotty dog sign seen on oblique lumbar radiographs represents a defect (fracture or lysis) in the pars interarticularis, indicating spondylolysis.

Question 95

Topic: Thoracolumbar Spine & Deformity

A 22-year-old male presents with axial back pain.

Based on a lateral lumbar spine radiograph showing isthmic spondylolisthesis, what is the primary anatomical defect responsible for this specific etiology?

. Facet joint degeneration
. Pars interarticularis defect
. Pedicle elongation
. Vertebral body fracture
. Ligamentum flavum hypertrophy

Correct Answer & Explanation

. Facet joint degeneration

Explanation

Isthmic spondylolisthesis is characterized by a defect in the pars interarticularis (spondylolysis), which allows the anterior column to translate forward while the posterior elements remain behind.

Question 96

Topic: Thoracolumbar Spine & Deformity
According to the Meyerding classification system for spondylolisthesis, what percentage of vertebral body slip defines a Grade III slip?
. 0-25%
. 25-50%
. 50-75%
. 75-100%
. > 100%

Correct Answer & Explanation

. 50-75%

Explanation

The Meyerding classification grades the degree of forward translation. Grade I is 0-25%, Grade II is 25-50%, Grade III is 50-75%, Grade IV is 75-100%, and Grade V (spondyloptosis) is >100%.

Question 97

Topic: Thoracolumbar Spine & Deformity

In evaluating adult spinal deformity, achieving appropriate sagittal balance is critical. Which of the following equations represents the fixed relationship between key pelvic parameters?

. Pelvic Incidence = Pelvic Tilt + Sacral Slope
. Pelvic Incidence = Pelvic Tilt - Sacral Slope
. Pelvic Tilt = Pelvic Incidence + Sacral Slope
. Sacral Slope = Pelvic Incidence + Pelvic Tilt
. Pelvic Incidence = Sacral Slope - Pelvic Tilt

Correct Answer & Explanation

. Pelvic Incidence = Pelvic Tilt + Sacral Slope

Explanation

Pelvic Incidence (PI) is a fixed morphological parameter unique to each individual. It dictates the functional parameters, specifically that PI = Pelvic Tilt (PT) + Sacral Slope (SS).

Question 98

Topic: Thoracolumbar Spine & Deformity
A 14-year-old female presents with severe mechanical back pain and a wide-based waddling gait. Radiographs reveal a Grade III L5-S1 isthmic spondylolisthesis with a slip angle of 55 degrees and a high pelvic incidence. What is the most appropriate surgical management?
. In situ posterolateral fusion of L5-S1
. Direct pars repair (e.g., Scott wiring)
. Posterior spinal fusion of L4-S1 with partial or complete reduction
. Anterior lumbar interbody fusion (ALIF) alone

Correct Answer & Explanation

. Posterior spinal fusion of L4-S1 with partial or complete reduction

Explanation

High-grade dysplastic or isthmic spondylolisthesis in adolescents with a high slip angle typically requires reduction and fusion extending to L4 to restore sagittal balance and prevent progressive deformity.

Question 99

Topic: Thoracolumbar Spine & Deformity

According to the Wiltse classification of spondylolisthesis, Type 1 (Dysplastic) is most commonly associated with which of the following anatomic abnormalities?

. A defect in the pars interarticularis
. An intact but elongated pars interarticularis
. Congenital deficiency of the superior S1 facet and inferior L5 facet
. Degenerative arthropathy of the facet joints without an osseous defect

Correct Answer & Explanation

. Congenital deficiency of the superior S1 facet and inferior L5 facet

Explanation

Dysplastic (Type 1) spondylolisthesis is caused by congenital abnormalities of the upper sacrum or the arch of L5, primarily involving deficient or abnormally oriented facet joints that allow forward slippage.

Question 100

Topic: Thoracolumbar Spine & Deformity

In the assessment of adult spinal deformity, Pelvic Incidence (PI) is a key morphological parameter that is fixed for each individual after skeletal maturity. It is mathematically defined as the sum of which two parameters?

. Pelvic tilt and lumbar lordosis
. Pelvic tilt and sacral slope
. Lumbar lordosis and sacral slope
. Thoracic kyphosis and lumbar lordosis

Correct Answer & Explanation

. Pelvic tilt and sacral slope

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter defined as the sum of the pelvic tilt (PT) and the sacral slope (SS). Thus, PI = PT + SS.

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