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Thoracolumbar Spine & Deformity MCQs

Practice Set 16 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 301

Topic: Thoracolumbar Spine & Deformity

A 55-year-old patient with significant genu varum and a known 2 cm leg length discrepancy (LLD) in the right leg is undergoing a full-length standing AP radiograph for deformity analysis. To ensure the radiograph captures the true alignment under functional weight-bearing conditions, what specific instruction should be given to the radiologic technologist regarding the LLD?

. The patient should stand with equal weight on both feet, ignoring the LLD.
. The patient should place their entire weight on the longer leg to maximize deformity visualization.
. Blocks must be placed under the shorter leg to level the pelvis.
. The X-ray beam should be angled to compensate for the pelvic tilt caused by the LLD.
. The patient should be positioned supine to eliminate the effect of weight-bearing on LLD.

Correct Answer & Explanation

. Blocks must be placed under the shorter leg to level the pelvis.

Explanation

Correct Answer: CThe text explicitly outlines the protocol for a perfect full-length radiograph: 'If there is a significant leg length discrepancy, blocks must be placed under the shorter leg to level the pelvis, ensuring the radiograph captures the true alignment under functional weight-bearing conditions.'Option A is incorrectbecause standing with equal weight without compensation for LLD would result in pelvic obliquity, distorting the true alignment.Option B is incorrectbecause placing all weight on one leg would not represent functional weight-bearing on both limbs and could introduce further alignment distortions.Option D is incorrectbecause angling the X-ray beam to compensate for pelvic tilt is not the standard method described for LLD. The goal is to level the pelvis physically.Option E is incorrectbecause the fundamental tool for deformity assessment is the 'weight-bearing, full-length anteroposterior (AP) radiograph.' A supine position would eliminate the functional weight-bearing component, which is critical for deformity analysis.

Question 302

Topic: Thoracolumbar Spine & Deformity

A radiologic technologist is being trained on the proper acquisition of full-length standing AP radiographs for deformity correction. The instructor emphasizes the 'Patella-Forward Rule.' Which of the following best describes the primary reason for strictly adhering to this rule?

. To ensure the patient's comfort during the prolonged standing position.
. To prevent superimposition of the fibula head over the tibia, improving visualization of the ankle joint.
. To ensure a true anteroposterior view of the knee joint, preventing rotational distortion of frontal plane angles.
. To standardize leg length measurements by eliminating rotational effects on limb length.
. To optimize the visualization of osteophytes and joint space narrowing within the knee.

Correct Answer & Explanation

. To ensure a true anteroposterior view of the knee joint, preventing rotational distortion of frontal plane angles.

Explanation

Correct Answer: CThe text explicitly states: 'The patella-forward position ensures a true AP view of the knee joint, which serves as the epicenter of lower limb alignment analysis.' It further explains that 'aligning the feet forward can induce significant rotation at the knee. This rotation distorts the frontal plane projection, rendering all subsequent joint orientation angle measurements completely inaccurate.' Therefore, the primary reason is to prevent rotational distortion and ensure accurate frontal plane assessment of the knee.Option A is incorrectbecause patient comfort, while important, is not the primary radiographic principle behind the patella-forward rule.Option B is incorrectbecause while rotation can affect fibula visualization, the primary and most critical impact of the patella-forward rule is on the knee joint's frontal plane projection and angular measurements, not specifically ankle joint visualization.Option D is incorrectbecause while rotation can subtly affect projected limb length, the primary impact of the patella-forward rule is on angular measurements in the frontal plane, not primarily on standardizing leg length measurements, which are more affected by pelvic tilt and overall limb length.Option E is incorrectbecause while a true AP view is generally better for all knee structures, the specific emphasis of the patella-forward rule in deformity correction is on accurate angular measurements for alignment, not primarily on intra-articular pathology like osteophytes or joint space narrowing.

Question 303

Topic: Thoracolumbar Spine & Deformity

When comparing the overall outcomes of surgical versus nonsurgical treatment of stable thoracolumbar burst fractures in patients without neurologic injury, 5 years following injury, the principle differences lie in Review Topic

. fracture kyphosis.
. reduction of retropulsed bone.
. pain reduction.
. incidence of complications.
. return to work.

Correct Answer & Explanation

. fracture kyphosis.

Explanation

When patients are compared at 5 years follow-up, there are no statistically significant differences between the two groups with respect to kyphosis, the degree of retropulsed bone resorption, pain and function levels, or the ability to return to work. Nonsurgical management of stable neurologically intact burst fractures has a very low incidence of complications.

Question 304

Topic: Thoracolumbar Spine & Deformity

Figures 2a and 2b show the radiograph and MRI scan of a 56-year-old woman who has low back pain and right leg pain. She has grade 3/5 toe and ankle dorsiflexion strength on the right side. Nonsurgical management has failed to provide relief; therefore, surgery should include Review Topic

. L5 pars repair.
. L5 laminectomy alone.
. L5 laminectomy and fusion.
. stand-alone anterior lumbar interbody fusion.
. L5-S1 total disk replacement.

Correct Answer & Explanation

. L5 laminectomy and fusion.

Explanation

The lateral radiograph and MRI scan demonstrate a grade 2 isthmic spondylolisthesis of L5 on S1. The radiograph shows a pars defect of L5. Isthmic spondylolistheses are most common at L5-S1. Degenerative spondylolistheses rarely progress beyond a grade 1 slip. The patient has frank neurologic weakness on the right side and nonsurgical management has failed to provide relief. In patients with significant motor weakness, neurologic decompression is indicated. An L5 pars repair is not recommended in patients with more than a grade 1 slip. Laminectomy alone can destabilize the spine and lead to further slippage and thus it is recommended to fuse the segment. A stand-alone anterior lumbar interbody fusion has a high failure rate with isthmic spondylolisthesis. Isthmic spondylolisthesis is a contraindication for lumbar total disk replacement. While there is some literature that supports fusion without laminectomy or decompression for patients with isthmic slips and radicular pain without neurologic deficit, this patient does not fulfill these criteria.

Question 305

Topic: Thoracolumbar Spine & Deformity

A 13-year-old girl presents with back pain for 6 months. Figures A and B are SPECT scan and CT images taken at the time of presentation. What is the most likely diagnosis? Review Topic

. Osteoid osteoma
. Bone island
. Spondylolysis
. Osteoblastic metastases
. Aneurysmal bone cyst

Correct Answer & Explanation

. Spondylolysis

Explanation

Thispatienthasspondylolysis.Spondylolysis is a common cause of back pain in children/adolescents. It is common in sports with repetitive hyperextension (gymnasts, weightlifters, football linemen). It is best seen on lateral and oblique radiographs, CT (best study to diagnose and delineate anatomy), and SPECT.Saifuddin et al. reviewed the orientation of the pars fracture. They found that only 32% of defects were oriented within 15° of the 45° lateral oblique plane and would bevisible on oblique radiographs. They thus recommend CT scans for spondylolysis.Cheung et al. reviewed spondylolysis and spondylolisthesis. They advocate pars repair for symptomatic spondylolysis and low-grade, mobile spondylolisthesis with pars defects cephalad to L5 and for those with multiple-level defects.Figure A is a 99mTc-MDP SPECT scan showing increased uptake at the right L5 pars interarticularis. Figure B is an axial helical CT image showing bilateral spondylolysis at L5. Illustration A is a corresponding sagittal reconstruction image demonstrating right pars fracture into the right L5 superior facet. Illustration B shows the appearance of osteoblastic metastasis (green arrow). Illustration C shows the options for pars repair.Incorrect

Question 306

Topic: Thoracolumbar Spine & Deformity

This condition is most prevalent in people of which ancestry?

. Northern European
. Asian
. Native American
. Sub-Saharan African

Correct Answer & Explanation

. Northern European

Explanation

DISCUSSIONThe radiograph of the lateral lumbosacral spine reveals an isthmic spondylolysis with a Meyerding grade 1 spondylolisthesis. The incidence of spondylolysis in the general population is around 5%, and grade 1 or 2 slips are present in the majority of children with a spondylolysis. Many cases of spondylolysis are painless and discovered incidentally, but, when painful, hyperextension of the lumbar spine may stress the area of the pars defect and exacerbate a patient’s symptoms. A diagnosis can usually be determined with a lateral radiograph of the lumbar spine. Although oblique lumbar radiographs are frequently ordered, several studies have shown that they do not increase diagnostic or prognostic accuracy. Progression of an isthmic spondylolysis, with or without a grade 1 or 2 listhesis, to a serious slip that mightnecessitate surgical intervention is rare and occurs in fewer than 5% of patients. Chance for progression diminishes with age, with patients at highest risk prior to the adolescent growth spurt. Spondylolysis may have a genetic component; an increased prevalence has been found in some families and in some ethnic groups, especially among the Native American population.

Question 307

Topic: Thoracolumbar Spine & Deformity
A patient who is an observant Jehovah’s Witness requires major surgery for scoliosis that will likely result in significant blood loss. Which of the following might the patient consider allowing the surgical team to use?
. Transfusion of whole blood
. Transfusion of packed red blood cells
. A cell saver with continuity maintained in a closed circuit
. Transfusion of plasma
. Transfusion of platelets

Correct Answer & Explanation

. A cell saver with continuity maintained in a closed circuit

Explanation

Jehovah’s Witnesses will not accept the transfusion of blood or blood products such as packed red or white cells, platelets, or plasma. However, many Jehovah’s Witnesses will accept the use of a cell saver in a closed circuit.

Question 308

Topic: Thoracolumbar Spine & Deformity
A 14-year-old boy is seen for back pain. Radiographic evaluation reveals a grade III isthmic spondylolisthesis. What measurement is most useful in predicting the likelihood of progression?
. Pelvic incidence
. Slip angle
. Sacral inclination
. Lumbosacral joint angle
. Sagittal rotation

Correct Answer & Explanation

. Slip angle

Explanation

DISCUSSION: Slip angle has been shown to be highly predictive of the risk for increased slippage in patients with spondylolisthesis. None of the other radiographic parameters listed has been shown to be predictive of the risk for increased slippage.

Question 309

Topic: Thoracolumbar Spine & Deformity

An MRI scan

. Observation and repeat radiographs in 4 months
. Application of a thoracolumbalsacral orthosis for 22 to 24 hours per day
. Electrical stimulation at night
. Physical therapy

Correct Answer & Explanation

. Observation and repeat radiographs in 4 months

Explanation

Treatment is based on the probability of curve progression. Major factors that influence curve progression are skeletal maturity, curve magnitude and curve type. Candidates for bracing are Risser 0, 1, or 2 and have a curve in the range of 20-40 degrees. Patients who present with curves between 30-40 degrees should be braced on presentation. Acceptable frequency of follow-up visits are at 4-6 month intervals. MRI scan would be indicated to evaluate a patient with atypical scoliosis, the patient described is a fairly typical scoliosis patient. Scoliosis treatment by electrical stimulation or physical therapy has not been shown to be effective.

Question 310

Topic: Thoracolumbar Spine & Deformity

-A likely candidate for treatment with a thoracic lumbosacral orthosis scoliosis brace is seen in

. Figure 178a.
. Figure 178b.
. Figure 178c.
. Figure 178d.
. Figure 178e.

Correct Answer & Explanation

. Figure 178a.

Explanation

Question 311

Topic: Thoracolumbar Spine & Deformity

Which of the following clinical scenarios represents an appropriate indication for convex hemiepiphysiodesis/hemiarthrodesis in the treatment of a child with a congenital spinal deformity?

. A 3-year-old child with a hemivertebra opposite a contralateral bar and thoracic scoliosis that measures 53°
. A 4-year-old child with a fully segmented L1 hemivertebra and scoliosis that measures 80°
. A 4-year-old child with a fully segmented T10 hemivertebra and scoliosis that measures 50°
. A 4-year-old child with a posterolateral hemivertebra at the thoracolumbar junction and a kyphoscoliotic deformity that measures 45°
. A 10-year-old child with a hemivertebra and scoliosis that measures 50°

Correct Answer & Explanation

. A 3-year-old child with a hemivertebra opposite a contralateral bar and thoracic scoliosis that measures 53°

Explanation

DISCUSSION: Convex hemiarthrodesis and hemiepiphysiodesis are procedures designed to gradually reduce curve magnitude in congenital scoliosis because of hemivertebrae.  They are used to surgically create an anterior and posterior bar to arrest growth on the convexity of the existing deformity.  Success of the technique is predicated on continued growth on the concave side of the deformity.  Prerequisites for this procedure include curves of limited length (less than or equal to five vertebrae), curves of reasonable magnitude (less than 70°), absence of kyphosis, concave growth potential, and appropriate age (younger than age 5 years).REFERENCE: Winter RB, Lonstein JE, Denis F, Sta-Ana de la Rosa H: Convex growth arrest for progressive congenital scoliosis due to hemivertebrae.  J Pediatr Orthop 1988;8:633-638.

Question 312

Topic: Thoracolumbar Spine & Deformity

Evaluation of an 8-year-old girl for scoliosis reveals a normal gestation, birth, and family history. Her parents state that she stopped gaining new motor skills at age 6 months. Examination shows the patient can sit independently, but she is nonverbal and she makes repetitive hand clapping movements. She has a 30-degree thoracolumbar kyphoscoliosis, and mildly increased tone in the hamstrings and gastrocnemius-soleus complex. What is the most likely diagnosis?

. Rett syndrome
. Cerebral palsy
. Myotonic dystrophy
. Fragile-X syndrome
. Adrenoleukodystrophy

Correct Answer & Explanation

. Rett syndrome

Explanation

Rett syndrome is a progressive encephalopathy of unknown etiology observed only in girls, who are apparently normal physically and mentally until the age of 6-18 months. It is characterized by autism, gait apraxia, dementia, stereotypical hand movements, loss of hand motor skills, hyperreflexia, spasticity, jerky trunk ataxia, seizures, and acquired microcephaly. Neurologically, abnormal development starts with hypotonia and is followed by ataxia and finally spasticity. The orthopaedic aspects of Rett syndrome have been mentioned only briefly in the literature. They include scoliosis, kyphosis, flexion contractures of the joints, and bilateral tight heel cords. Scoliosis is the major orthopaedic deformity in Rett syndrome. Eight of Ten girls in one series had developed scoliosis at the average age of 11 years. All eight girls had C-shaped thoracolumbar neuromuscular curves with pelvic obliquity. The right thoracolumbar curve was by far the most common pattern, occurring in seven patients (88%), whereas only one patient (12%) had a left thoracolumbar curve.

Question 313

Topic: Thoracolumbar Spine & Deformity

A patient who is an observant Jehovah’s Witness requires major surgery for scoliosis that will likely result in significant blood loss. Which of the following might the patient consider allowing the surgical team to use? Review Topic

. Transfusion of whole blood
. Transfusion of packed red blood cells
. A cell saver with continuity maintained in a “closed circuit”
. Transfusion of plasma
. Transfusion of platelets

Correct Answer & Explanation

. A cell saver with continuity maintained in a “closed circuit”

Explanation

Jehovah’s Witnesses will not accept the transfusion of blood or blood products such as packed red or white cells, platelets, or plasma. However, many Jehovah’s Witnesses will accept the use of a cell saver in a “closed circuit.”

Question 314

Topic: Thoracolumbar Spine & Deformity

Which of the following conditions routinely requires early surgical intervention in patients with Marfan syndrome? Review Topic

. Kyphosis
. Ankle instability
. Protrusio acetabula
. Progressive scoliosis
. Pseudarthrosis of the tibia

Correct Answer & Explanation

. Kyphosis

Explanation

Marfan syndrome is a challenging disease for the orthopaedic surgeon. Most problems of joint laxity, acetabular protrusio, and minor scoliosis curves are treated nonsurgically. Pseudarthrosis of the tibia is not seen in Marfan syndrome; it is more common in patients with neurofibromatosis (NF-1). Treating kyphosis is risky for vertebral subluxation. Rapidly progressive scoliosis in immature patients is associated with higher surgical complications, but surgery is indicated. Overcorrection is associated with significant cardiovascular complications and should be avoided.

Question 315

Topic: Thoracolumbar Spine & Deformity

Figure 37 shows the standing lateral radiograph of a 62-year-old woman who reports lower back pain and the inability to stand upright. What permanent anatomic pelvic parameter should be measured and considered when determining the amount of lumbar lordosis correction that will be necessary to obtain sagittal balance? Review Topic

. Pelvic tilt
. Pelvic incidence
. Sacral slope
. Acetabular version
. Femoral version

Correct Answer & Explanation

. Pelvic tilt

Explanation

Pelvic incidence (PI) is the anatomic angle between the sacral end plate and a line connecting the center of the femoral heads. Increased pelvic incidence has been found to correlate with the incidence and severity of spondylolisthesis. Patients with increased PI require increased lumbar lordosis to restore sagittal balance. Pelvic tilt (PT) and sacral slope (SS) have also been found to correlate with lumbar lordosis; however, both PT and SS can change depending on pelvic rotation. PI is the onlypermanent pelvic parameter that is unaffected by pelvic rotation. Acetabular and femoral version have not been found to be associated with lumbar lordosis.

Question 316

Topic: Thoracolumbar Spine & Deformity

The most important radiographic predictor of a good clinical outcome following adult spinal deformity surgery is correction of Review Topic

. pelvic incidence.
. listhesis.
. rotational deformity.
. sagittal balance.
. coronal deformity.

Correct Answer & Explanation

. pelvic incidence.

Explanation

Surgery for adult deformity, such as degenerative scoliosis and kyphosis, has gained popularity in recent years. Improved fixation techniques, such as pedicle screws, and increased familiarity and comfort with anterior surgery have resulted in greater curve correction. Multiple studies have demonstrated that correction of sagittal balance is the most important radiographic predictor of a good clinical outcome. While correction of coronal deformity is often a surgical goal, it does not appear to be as important in improving patient outcomes. Correction of listhesis, particularly in the surgical treatment of adult spondylolisthesis, is controversial because its impact on clinical outcomes has not been clearly established. Rotational deformities, though often present with adult scoliosis, are difficult to correct. Pelvic incidence is a fixed parameter that is unchanged with surgery.

Question 317

Topic: Thoracolumbar Spine & Deformity

A 45-year-old woman has idiopathic scoliosis. Surgery is to include an anterior thoracic release through an open left thoracotomy. The thoracotomy will have what effect on the patient’s pulmonary function postoperatively? Review Topic

. Unaffected
. Transiently reduced postoperatively but ultimately improves to greater than preoperative function
. Transiently reduced immediately postoperatively but then quickly returns to preoperative levels
. Improves postoperatively due to correction of the scoliosis and is maintained long term
. Reduced postoperatively and often remains reduced long term

Correct Answer & Explanation

. Unaffected

Explanation

A thoracotomy in an adult with idiopathic scoliosis causes a reduction in pulmonary function that often does not return to preoperative levels. What pulmonary function that does recover, recovers over many months. Long-term improvement in pulmonaryfunction, compared to preoperative function, is rarely seen. This should be considered in planning surgical intervention in adults with scoliosis.

Question 318

Topic: Thoracolumbar Spine & Deformity
A 14-year-old boy is seen for back pain. Radiographic evaluation reveals a grade III isthmic spondylolisthesis. What measurement is most useful in predicting the likelihood of progression?
. Pelvic incidence
. Slip angle
. Sacral inclination
. Lumbosacral joint angle
. Sagittal rotation

Correct Answer & Explanation

. Slip angle

Explanation

Slip angle has been shown to be highly predictive of the risk for increased slippage in patients with spondylolisthesis. None of the other radiographic parameters listed has been shown to be predictive of the risk for increased slippage.

Question 319

Topic: Thoracolumbar Spine & Deformity

What is the minimum hours per day of wear that has been correlated with the effectiveness of bracing on curve progression in idiopathic scoliosis? Review Topic

. Prescribed brace wear 23 hours/day
. Prescribed brace wear 16 hours/day
. Actual brace wear more than 12 hours/day
. Actual brace wear 6 hours/day

Correct Answer & Explanation

. Actual brace wear more than 12 hours/day

Explanation

The efficacy of brace treatment for patients with adolescent idiopathic scoliosis is controversial because its effectiveness remains unproven. One of the challenges is patient noncompliance with prescribed bracing regimens. A recent study investigated curve progression based on actual brace wear using a temperature sensor to accurately assess brace wear. The total hours of brace wear correlated with lack of curve progression with a dose-response effect noted. Curves did not progress in 82% of patients who actually wore the brace more than 12 hours per day. For those who wore the brace for fewer than 7 hours per day, curves progressed in 69%. Prescribed bracing regimens (eg, 16 hours/day or 23 hours/day) had no effect on actual brace wear or curve progression.

Question 320

Topic: Thoracolumbar Spine & Deformity

What factor is associated with the highest risk for in-hospital complications for patients undergoing a lumbar fusion for degenerative spondylolisthesis? Review Topic

. Hospital size
. Gender
. Race
. Age
. One comorbidity

Correct Answer & Explanation

. Hospital size

Explanation

Age and having three or more comorbidities is associated with a higher rate of complications in patients undergoing a lumbar fusion for lumbar degenerative spondylolisthesis. Race, gender, and hospital size have not been found to be associated with higher complication rates.

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