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Thoracolumbar Spine & Deformity MCQs

Practice Set 9 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 161

Topic: Thoracolumbar Spine & Deformity

Which of the following characterizes Russell-Silver syndrome:

. Hemihypertrophy
. Hemiatrophy
. Acromegaly
. Macrodactyly
. Precocious puberty

Correct Answer & Explanation

. Hemiatrophy

Explanation

Russell-Silver syndrome is characterized by a small triangular face, hemiatrophy of up to 5 cm, delay in skeletal age, and sometimes a developmental delay. Scoliosis is commonly found in patients with Russell- Silver syndrome.

Question 162

Topic: Thoracolumbar Spine & Deformity
Patients with which one of the following curve types associated with idiopathic scoliosis are at increased risk of shortness of breath?
. Thoracic curves larger than 80°
. Thoracolumbar curves larger than 80°
. Thoracolumbar curves larger than 100°
. Lumbar curves larger than 80°
. Lumbar curves larger than 100°

Correct Answer & Explanation

. Thoracic curves larger than 80°

Explanation

Idiopathic scoliosis is associated with measurable decreases in pulmonary function in thoracic curves larger than 60° to 70°, but a clinically significant increase in risk of shortness of breath has been shown only in thoracic curves larger than 80°.

Question 163

Topic: Thoracolumbar Spine & Deformity
Which of the following patients with infantile idiopathic scoliosis can be observed without a magnetic resonance image (MRI)?
. A patient with a curve less than 20°
. A patient with a normal neurologic examination
. A patient with a right thoracic curve
. A patient younger than 2 years old
. A patient without any pain

Correct Answer & Explanation

. A patient younger than 2 years old

Explanation

Patients with idiopathic infantile scoliosis have a 22% incidence of abnormalities that can be viewed on MRI. Syrinx and Chiari malformation are the most common abnormalities, with a similar rate as that found in patients with juvenile idiopathic scoliosis. The left thoracic curve pattern is most commonly seen in infantile patients, but a right thoracic curve is not protective. Age, freedom from pain, or a normal neurologic examination are also not protective. Magnetic resonance imaging is recommended for all infantile curves larger than 20°.

Question 164

Topic: Thoracolumbar Spine & Deformity

For a patient who has thoracic idiopathic scoliosis of the surgical range, the distance between the thecal sac and the apical thoracic pedicle on the concave side is:

. Less than 1 mm
. 2 mm
. 3 mm
. 4 mm
. 5 mm

Correct Answer & Explanation

. Less than 1 mm

Explanation

The distance between the apical thoracic pedicle and the thecal sac is less than 1 mm on the concave side.

Question 165

Topic: Thoracolumbar Spine & Deformity

A 1-year-old boy presents with an infantile idiopathic scoliosis curve measuring 30 degrees. Which radiographic measurement is the most reliable prognostic indicator for curve progression?

. Cobb angle magnitude alone
. Nash-Moe rotation
. Rib-vertebral angle difference (RVAD) of Mehta
. Risser sign
. Apical vertebral translation

Correct Answer & Explanation

. Rib-vertebral angle difference (RVAD) of Mehta

Explanation

Mehta's Rib-Vertebral Angle Difference (RVAD) is the most critical prognostic factor for infantile idiopathic scoliosis. An RVAD greater than 20 degrees strongly predicts curve progression.

Question 166

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast complains of chronic lower back pain. Radiographs show a grade II spondylolisthesis at L5-S1. What radiographic parameter is most predictive of future slip progression?

. Pelvic incidence
. Sacral slope
. Slip angle (sagittal roll)
. Lumbar lordosis
. Intervertebral disc height

Correct Answer & Explanation

. Slip angle (sagittal roll)

Explanation

The slip angle (sagittal roll or kyphosis) is the most important radiographic predictor for the progression of a dysplastic spondylolisthesis. High slip angles indicate greater instability.

Question 167

Topic: Thoracolumbar Spine & Deformity

In a 6-year-old boy diagnosed with Duchenne Muscular Dystrophy (DMD), the administration of systemic corticosteroids is aimed primarily at achieving which of the following?

. Reversing the dystrophin gene mutation
. Curing the associated cardiomyopathy
. Preventing the development of scoliosis indefinitely
. Prolonging independent ambulation
. Enhancing fine motor skills in the upper extremities

Correct Answer & Explanation

. Prolonging independent ambulation

Explanation

Systemic corticosteroids are a mainstay of medical therapy for Duchenne Muscular Dystrophy. They have been shown to prolong independent ambulation, preserve pulmonary function, and delay the onset of severe scoliosis.

Question 168

Topic: Thoracolumbar Spine & Deformity

A 25-year-old male sustains a burst fracture of L1 after a fall. He has no neurologic deficits. Which radiographic finding is the strongest indication for operative stabilization rather than non-operative management?

. 10 degrees of regional kyphosis
. 20% loss of anterior vertebral body height
. Disruption of the posterior ligamentous complex (PLC)
. Widening of the pedicles on AP radiograph
. Retropulsion of bone into 10% of the spinal canal

Correct Answer & Explanation

. Disruption of the posterior ligamentous complex (PLC)

Explanation

Disruption of the posterior ligamentous complex (PLC) makes a thoracolumbar burst fracture highly mechanically unstable. According to the TLICS system, PLC disruption is a strong indication for surgical stabilization.

Question 169

Topic: Thoracolumbar Spine & Deformity

A 45-year-old man falls from a height and sustains an L1 burst fracture. His neurological examination is normal. A CT scan demonstrates 30% canal compromise, and MRI confirms an intact posterior ligamentous complex. His Thoracolumbar Injury Classification and Severity (TLICS) score is calculated as 2. What is the most appropriate management?

. Anterior corpectomy and fusion
. Posterior spinal fusion
. Short segment pedicle screw fixation
. Thoracolumbosacral orthosis (TLSO)
. Laminectomy alone

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO)

Explanation

A burst fracture with intact neurological status and an intact posterior ligamentous complex typically scores a 2 on the TLICS system. The standard of care for a neurologically intact patient with a stable burst fracture is nonoperative management with a TLSO.

Question 170

Topic: Thoracolumbar Spine & Deformity
A 16-year-old gymnast presents with persistent lower back pain. Radiographs reveal an L5-S1 isthmic spondylolisthesis with 65% forward translation of L5 on S1. According to the Meyerding classification, what grade is this slip?
. Grade I
. Grade II
. Grade III
. Grade IV
. Spondyloptosis

Correct Answer & Explanation

. Grade III

Explanation

The Meyerding classification grades spondylolisthesis based on the percentage of vertebral translation: Grade I (0-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (>100% or spondyloptosis). A 65% slip is Grade III.

Question 171

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast complains of mechanical lower back pain for 8 months that limits her sports participation. Lateral lumbar radiographs reveal a bilateral pars interarticularis defect at L5 with a 40% anterior translation of L5 on S1 (Grade II isthmic spondylolisthesis). She has failed 6 months of structured physical therapy. What is the most appropriate surgical treatment?

. L5-S1 in situ posterolateral fusion
. L4-S1 decompressive laminectomy without fusion
. Anterior lumbar interbody fusion (ALIF) at L4-L5
. Insertion of an interspinous process distraction device
. Transforaminal epidural steroid injections followed by bracing

Correct Answer & Explanation

. L5-S1 in situ posterolateral fusion

Explanation

For a symptomatic, low-grade (Grade I or II) isthmic spondylolisthesis in an adolescent who has failed conservative treatment, an L5-S1 in situ posterolateral arthrodesis is the surgical treatment of choice.

Question 172

Topic: Thoracolumbar Spine & Deformity
An appropriate indication for preoperative MRI in adolescent idiopathic scoliosis is:
. Any curve requiring surgery
. Any curve more than 90°
. An abnormal neurologic examination
. Any progressive deformity in a male
. Any progression of 12° in 6 months

Correct Answer & Explanation

. An abnormal neurologic examination

Explanation

The only absolute indication for preoperative MRI in idiopathic adolescent scoliosis is an abnormal neurologic exam or abnormal curve pattern.

Question 173

Topic: Thoracolumbar Spine & Deformity
The mean Cobb measurement for idiopathic scoliosis curves with a 7° angle of trunk rotation (ATR) is:
. 10°
. 15°
. 20°
. 25°
. 30°

Correct Answer & Explanation

. 20°

Explanation

Although the angle of trunk rotation (ATR) does not convert directly to a Cobb angle, there are population-based figures for mean curve at each ATR. The mean Cobb angle for curves having a 7° ATR is 20°.

Question 174

Topic: Thoracolumbar Spine & Deformity

The normal values (±2 standard deviations) for kyphosis in the general population of children and adolescents are:

. 20° to 50°
. 20° to 40°
. 25° to 45°
. 25° to 60°
. 30° to 60°

Correct Answer & Explanation

. 20° to 50°

Explanation

The normal values for kyphosis in the general population (2 standard deviations above and below the mean) are 20° to 50°.

Question 175

Topic: Thoracolumbar Spine & Deformity

The most common cause of neurologic deficit in patients with Down syndrome is:

. Basilar invagination
. Atlanto-occipital instability
. Atlantoaxial instability
. Subaxial instability
. C ervical kyphosis

Correct Answer & Explanation

. Atlantoaxial instability

Explanation

Basilar invagination is extremely rare in this syndrome, and problematic cervical kyphosis is equally uncommon. Atlanto-occipital translation and subaxial instability occur but rarely cause symptoms. Atlantoaxial instability is the most common of the cervical abnormalities listed to cause neurologic compromise in Down syndrome. Nevertheless, surgery is only indicated if the atlantoaxial interval exceeds 6 mm, or causes neurologic deficits.

Question 176

Topic: Thoracolumbar Spine & Deformity
A thoracic curve of more than 50° due to an idiopathic adolescent scoliosis curve has an increased risk of causing all except which of the following consequences in adulthood, when compared to the general population:
. Restrictive lung disease
. Obstructive lung disease
. Back pain
. Less positive body image
. Increase in curvature

Correct Answer & Explanation

. Restrictive lung disease

Explanation

Idiopathic adolescent scoliosis is likely to progress in adulthood if it exceeds 50°. The rate of progression in adults is slower than during adolescence; about 1° per year. Nevertheless, it is likely to have some effect on pulmonary function later during adulthood. The effect is one of restrictive rather than obstructive lung disease. There is an increase in the risk of back pain, although it is rarely disabling. Patients with idiopathic scoliosis as a group have a more negative body image, although it is not a serious life impairment. In all of these parameters, there are individual exceptions.

Question 177

Topic: Thoracolumbar Spine & Deformity
Which of the following factors are not related to the success of brace treatment for idiopathic scoliosis?
. Curve size at start of treatment
. Curve correction in brace
. Number of hours worn
. Gender
. Positive family history of scoliosis

Correct Answer & Explanation

. Positive family history of scoliosis

Explanation

A lower chance of curve control with brace treatment has been shown with curves greater than 40°, correction of less than 50% in brace, brace worn fewer than 16 hours per day, or male gender. Positive family history has not been shown to be related to curve progression or chance of control.

Question 178

Topic: Thoracolumbar Spine & Deformity

A 12-year-old patient has a rigid, 135° scoliosis. Gradually increasing halo- gravity traction is planned in correcting the curve. The maximum weight that should be used is:

. 15% of body weight
. 20% of body weight
. 25% of body weight
. 30% of body weight
. 35% to 45% of body weight

Correct Answer & Explanation

. 35% to 45% of body weight

Explanation

Halo-gravity traction is a safe and effective means of gradually correcting large curves. It allows balanced force application and continuous neurological monitoring. C ranial and peripheral nerves should be monitored. The weight can be increased gradually up to 35% to 45% of body weight, as documented in published series.

Question 179

Topic: Thoracolumbar Spine & Deformity

Which of the following is the greatest risk factor for the progression of isthmic spondylolisthesis in a pediatric patient?

. Male gender
. Presentation after age 15
. High slip angle (>45 degrees)
. Low pelvic incidence
. Grade I initial slippage

Correct Answer & Explanation

. High slip angle (>45 degrees)

Explanation

A high slip angle, typically greater than 45 to 50 degrees, is the most significant radiographic predictor for the progression of isthmic spondylolisthesis. Other risk factors include young age at presentation, female gender, and dysplastic morphology.

Question 180

Topic: Thoracolumbar Spine & Deformity

Emery-Dreifuss muscular dystrophy is unique among the dystrophies because of the development of which deformity:

. Neck extension contracture
. Hip abduction
. Knee flexion
. Equinus contracture
. Scoliosis

Correct Answer & Explanation

. Neck extension contracture

Explanation

Emery-Dreifuss muscular dystrophy is an x-linked disorder of emerin, which is a cell-membrane protein. Symptoms and signs develop within the first decade in most cases. A unique deformity, neck extension contracture, develops, in addition to elbow flexion contractures and peroneal wasting. The other deformities listed above are common in many dystrophies.

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