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Thoracolumbar Spine & Deformity MCQs

Practice Set 8 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 141

Topic: Thoracolumbar Spine & Deformity

A 15-year-old male gymnast complains of chronic low back pain worsened by extension. Oblique radiographs demonstrate a 'collar on the Scottie dog' sign at L5. What anatomical structure is defective?

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

Correct Answer & Explanation

. Pars interarticularis

Explanation

The 'collar on the Scottie dog' sign seen on oblique lumbar radiographs represents a defect or fracture in the pars interarticularis, which is the hallmark of isthmic spondylolysis.

Question 142

Topic: Thoracolumbar Spine & Deformity
Adults with untreated Scheuermann's kyphosis do not differ from controls in terms of this parameter:
. Pulmonary function
. Severity of back pain
. Activity levels in job
. Location of greatest backache
. Presence of scoliosis

Correct Answer & Explanation

. Pulmonary function

Explanation

Patients with Scheuermann's kyphosis have no decrease in pulmonary function compared to controls; however, they have increased severity of back pain, seek jobs with lower activity levels, and have more thoracic back pain and less trunk extension. They also have a 30% incidence of scoliosis of less than 35°.

Question 143

Topic: Thoracolumbar Spine & Deformity

A 14-year-old boy has grade 1 isthmic L5-S1 spondylolisthesis. He has no back pain and wants to play football. The patient should be advised to:

. Play football if his condition is treated by grafting and wiring
. Play football if he has a L5-S1 fusion
. Play football if he wears a lumbosacral orthosis during all games
. Not play football at all
. Play football as desired

Correct Answer & Explanation

. Play football as desired

Explanation

Asymptomatic spondylolisthesis occurs in approximately 5% of the pediatric population. Slips of up to grade 1 develop in at least one third of patients with asymptomatic spondylolisthesis. Most patients with asymptomatic spondylolisthesis are minimally symptomatic or asymptomatic. The patient presented in this scenario may be allowed to play football as long as he understands that he may develop symptoms.

Question 144

Topic: Thoracolumbar Spine & Deformity

What is the primary indication for initiating Milwaukee brace treatment in a patient with Scheuermann's kyphosis?

. A rigid curve of >75 degrees in a skeletally mature patient
. A progressive curve of 55 to 75 degrees in a skeletally immature patient (Risser 0-2)
. A flexible curve of <50 degrees in a skeletally mature patient
. Any kyphotic curve with documented multiple Schmorl's nodes
. Lumbar hyperlordosis compensatory to a 40-degree thoracic kyphosis

Correct Answer & Explanation

. A progressive curve of 55 to 75 degrees in a skeletally immature patient (Risser 0-2)

Explanation

Bracing is typically indicated for progressive Scheuermann's kyphosis between 50 and 75 degrees in skeletally immature patients with significant remaining growth.

Question 145

Topic: Thoracolumbar Spine & Deformity

Which clinical maneuver is most useful in differentiating Scheuermann's kyphosis from a postural roundback deformity?

. Adam's forward bend test
. Thomas test
. Hyperextension test (prone or supine)
. Straight leg raise test
. Ober test

Correct Answer & Explanation

. Hyperextension test (prone or supine)

Explanation

Scheuermann's kyphosis is characterized by a structural, rigid deformity that does not correct upon hyperextension, whereas postural kyphosis is flexible and will fully correct.

Question 146

Topic: Thoracolumbar Spine & Deformity

In an adolescent patient with untreated Scheuermann's kyphosis who reports pain, where is the pain most typically located?

. At the cervicothoracic junction
. Directly over the apex of the kyphotic deformity
. At the lumbosacral junction radiating to the buttocks
. Radiating down the bilateral lower extremities
. Anteriorly in the chest wall mimicking costochondritis

Correct Answer & Explanation

. Directly over the apex of the kyphotic deformity

Explanation

Pain in Scheuermann's disease is typically described as a non-radiating, dull ache located directly over the apex of the thoracic or thoracolumbar kyphosis.

Question 147

Topic: Thoracolumbar Spine & Deformity

According to the Sorensen criteria, what is the strict radiographic definition required to diagnose classical Scheuermann's kyphosis?

. Anterior wedging of >5 degrees in at least two adjacent vertebrae
. Anterior wedging of >5 degrees in at least three adjacent vertebrae
. Anterior wedging of >10 degrees in at least two adjacent vertebrae
. Anterior wedging of >10 degrees in at least three adjacent vertebrae
. Thoracic kyphosis >45 degrees with Schmorl's nodes

Correct Answer & Explanation

. Anterior wedging of >5 degrees in at least three adjacent vertebrae

Explanation

The Sorensen criteria for diagnosing Scheuermann's kyphosis require anterior wedging of greater than 5 degrees in at least three consecutive vertebrae. Additional common findings include Schmorl's nodes and endplate irregularities.

Question 148

Topic: Thoracolumbar Spine & Deformity

Long-term natural history studies comparing adults with untreated Scheuermann's kyphosis to the general population demonstrate that patients with Scheuermann's have increased back pain. However, they do NOT significantly differ from the general population in which of the following?

. Degree of structural thoracic kyphosis
. Amount of compensatory lumbar lordosis
. Rates of severe occupational limitations or disability
. Incidence of Schmorl's nodes
. Presence of vertebral endplate irregularities

Correct Answer & Explanation

. Rates of severe occupational limitations or disability

Explanation

While adults with untreated Scheuermann's kyphosis have higher rates of back pain and cosmetic concerns, long-term studies show no significant difference in severe disability, neurologic compromise, or occupational limitations compared to controls.

Question 149

Topic: Thoracolumbar Spine & Deformity

Wide posterior release is often necessary to achieve adequate correction in Scheuermann's kyphosis. What anatomic structures are resected during a standard Ponte osteotomy?

. The anterior longitudinal ligament and intervertebral disc
. The spinous process, lamina, ligamentum flavum, and bilateral facet joints
. The entire vertebral body and adjacent pedicles
. The transverse processes and attached ribs
. The pars interarticularis only

Correct Answer & Explanation

. The spinous process, lamina, ligamentum flavum, and bilateral facet joints

Explanation

A Ponte osteotomy is a posterior column shortening osteotomy that involves wide resection of the spinous process, lamina, ligamentum flavum, and the bilateral facet joints to drastically increase posterior flexibility.

Question 150

Topic: Thoracolumbar Spine & Deformity

Which of the following represents the classic Sorensen criteria for the radiographic diagnosis of Scheuermann's kyphosis?

. Anterior wedging of >10 degrees in two consecutive vertebrae
. Anterior wedging of >5 degrees in three or more consecutive vertebrae
. Thoracic kyphosis >45 degrees with isolated Schmorl's nodes
. Endplate irregularities and disc space narrowing without wedging
. Vertebral body wedging of >15 degrees at the apex

Correct Answer & Explanation

. Anterior wedging of >5 degrees in three or more consecutive vertebrae

Explanation

The Sorensen criteria define classic Scheuermann's disease as anterior wedging of greater than 5 degrees in at least three consecutive vertebrae.

Question 151

Topic: Thoracolumbar Spine & Deformity

Which of the following radiographic views is considered the gold standard for assessing the flexibility of a rigid Scheuermann's kyphosis prior to surgical planning?

. Standing posteroanterior radiograph
. Standing lateral radiograph
. Supine cross-table lateral with a bolster at the apex
. Prone push-prone radiograph
. Supine side-bending radiograph

Correct Answer & Explanation

. Supine cross-table lateral with a bolster at the apex

Explanation

The supine cross-table lateral radiograph with a hyperextension bolster placed under the apex of the curve best demonstrates the flexibility and correctability of the kyphosis.

Question 152

Topic: Thoracolumbar Spine & Deformity

When counseling a 13-year-old patient regarding brace treatment for a 60-degree Scheuermann's kyphosis, which factor is the strongest predictor of ultimate treatment success?

. A curve magnitude strictly between 60 and 70 degrees
. Skeletal maturity nearing Risser 3
. Initial in-brace correction of at least 40%
. An apex at or above T5
. Male gender

Correct Answer & Explanation

. Initial in-brace correction of at least 40%

Explanation

Similar to idiopathic scoliosis, the amount of initial in-brace correction is highly predictive of final outcomes in Scheuermann's disease. Correction of at least 15 degrees or >40% in the brace correlates with a successful result.

Question 153

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast presents with persistent low back pain. Radiographs demonstrate a grade II isthmic spondylolisthesis at L5-S1. What is the underlying anatomic defect?

. Congenital dysplasia of the facet joints
. Pars interarticularis defect
. Degenerative disc disease
. Pedicle fracture
. Sacral agenesis

Correct Answer & Explanation

. Pars interarticularis defect

Explanation

Isthmic spondylolisthesis (Type II) is caused by a defect or stress fracture in the pars interarticularis. It is commonly seen in young athletes like gymnasts due to repetitive hyperextension.

Question 154

Topic: Thoracolumbar Spine & Deformity

In patients with idiopathic adolescent scoliosis, clinically noticeable shortness of breath from restrictive lung disease begins to occur at a mean curve of:

. 45° thoracic
. 45° lumbar
. 55° thoracic
. 75° thoracic
. 95° thoracic

Correct Answer & Explanation

. 75° thoracic

Explanation

Clinically noticeable pulmonary compromise begins to occur at a mean curve of 75° thoracic, although a decrease can be measured by pulmonary function testing with curves as little as 50°. C or pulmonale does not occur until a curve is larger then 100°.

Question 155

Topic: Thoracolumbar Spine & Deformity
A 14-year-old gymnast presents with back pain and L5 radiculopathy. Radiographs show a Grade III isthmic spondylolisthesis at L5-S1 with a high pelvic incidence. Which of the following is the most appropriate surgical strategy if conservative management fails?
. Pars interarticularis repair (Buck's procedure)
. L5-S1 posterior uninstrumented in situ fusion
. L5-S1 posterior instrumented fusion with reduction
. L4-S1 posterior instrumented fusion
. Anterior lumbar interbody fusion without posterior instrumentation

Correct Answer & Explanation

. L4-S1 posterior instrumented fusion

Explanation

For high-grade (Grade III or IV) isthmic spondylolisthesis in adolescents, L4 to S1 posterior instrumented fusion is often recommended due to the severe slip angle and high pelvic incidence. A single-level L5-S1 fusion in high-grade slips carries a high rate of hardware failure and pseudarthrosis.

Question 156

Topic: Thoracolumbar Spine & Deformity

In a patient with idiopathic adolescent scoliosis, at what thoracic curve magnitude does right-sided heart failure (cor pulmonale) typically begin to occur?

. 60 degrees
. 80 degrees
. 100 degrees
. Greater than 110 degrees
. 140 degrees

Correct Answer & Explanation

. Greater than 110 degrees

Explanation

In idiopathic scoliosis, restrictive lung disease becomes clinically significant at curves >80 degrees. However, right-sided heart failure (cor pulmonale) typically occurs when the thoracic curve exceeds 110 degrees.

Question 157

Topic: Thoracolumbar Spine & Deformity

When evaluating an AP radiograph of an infant with idiopathic scoliosis, a Rib Vertebral Angle Difference (RVAD) of Mehta greater than what value is considered highly predictive of curve progression?

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

Correct Answer & Explanation

. 20 degrees

Explanation

The Rib Vertebral Angle Difference (RVAD) of Mehta evaluates the risk of progression in infantile idiopathic scoliosis. An RVAD greater than 20 degrees strongly predicts an aggressive, progressing curve rather than a resolving one.

Question 158

Topic: Thoracolumbar Spine & Deformity

Which of the following spinopelvic parameters is an anatomical constant for a given individual and, when elevated, strongly correlates with a higher risk of spondylolisthesis progression?

. Thoracic kyphosis
. Pelvic incidence
. Lumbar lordosis
. Sacral slope
. Pelvic tilt

Correct Answer & Explanation

. Pelvic incidence

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter that defines the shape of the pelvis. A high PI creates a steeper lumbosacral angle, resulting in increased shear forces across the L5-S1 junction and a higher risk of spondylolisthesis progression.

Question 159

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast has a Grade II isthmic spondylolisthesis at L5-S1. She complains of radicular pain and hamstring tightness. Which of the following best explains the mechanism of her hamstring tightness?

. Direct compression of the S1 nerve root
. Reflexive spasm to stabilize the pelvis and prevent further sagittal slip
. L5 nerve root irritation in the neural foramen
. Piriformis syndrome secondary to altered gait
. Tethered cord syndrome

Correct Answer & Explanation

. Reflexive spasm to stabilize the pelvis and prevent further sagittal slip

Explanation

Hamstring tightness in pediatric isthmic spondylolisthesis (the "Phalen-Dickson sign") is a reflexive spasm meant to vertically orient the pelvis (retroversion) to decrease lumbar lordosis and prevent further anterior translation.

Question 160

Topic: Thoracolumbar Spine & Deformity

According to the Sorensen criteria, a definitive radiographic diagnosis of Scheuermann's kyphosis requires anterior wedging of at least 5 degrees in a minimum of how many consecutive vertebrae?

. Two
. Three
. Four
. Five
. Six

Correct Answer & Explanation

. Three

Explanation

The classic Sorensen criteria define Scheuermann's disease as hyperkyphosis with anterior wedging of at least 5 degrees in three or more adjacent vertebral bodies. Endplate irregularities and Schmorl's nodes are also typical findings.

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