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 381
Topic: Thoracolumbar Spine & Deformity
In preoperative planning for adult spinal deformity surgery, the surgeon calculates the patient's pelvic incidence (PI). Which of the following statements best describes this vital radiographic parameter?
Correct Answer & Explanation
. It is a fixed morphological parameter mathematically equal to pelvic tilt plus sacral slope
Explanation
Pelvic incidence (PI) is a fixed anatomical parameter unique to each individual's pelvis and does not change with posture or age. It is defined mathematically as the sum of Pelvic Tilt (PT) and Sacral Slope (SS) (i.e., PI = PT + SS).
Question 382
Topic: Thoracolumbar Spine & Deformity
According to the Wiltse classification of spondylolisthesis, which type is characterized by congenital abnormalities of the upper sacrum or the neural arch of L5, leading to progressive slipping primarily seen in pediatric patients?
Correct Answer & Explanation
. Type I (Dysplastic)
Explanation
The Wiltse classification categorizes spondylolisthesis. Type I is Dysplastic, caused by congenital anomalies of the lumbosacral junction (e.g., attenuated pars, maloriented facets) and has a high rate of progression. Type II is Isthmic (pars defect). Type III is Degenerative. Type IV is Traumatic (fracture in areas other than the pars). Type V is Pathologic (generalized or localized bone disease).
Question 383
Topic: Thoracolumbar Spine & Deformity
A 35-year-old male sustains an L1 burst fracture in a motor vehicle collision. He is neurologically intact. MRI demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is his total score, and what is the recommended management?
Correct Answer & Explanation
. Score 2, non-operative management
Explanation
The TLICS system assigns points based on morphology, neurologic status, and posterior ligamentous complex (PLC) integrity. Burst fracture morphology = 2 points. Neurologically intact = 0 points. Intact PLC = 0 points. Total score = 2. A score of 3 or less is an indication for non-operative management. A score of 4 is indeterminate (surgeon's choice), and 5 or more warrants surgical intervention.
Question 384
Topic: Thoracolumbar Spine & Deformity
A 45-year-old female presents with an L1 burst fracture following a fall from height. Neurological examination is completely normal. MRI reveals an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is her total score and the recommended management?
Correct Answer & Explanation
. Score 2; non-operative management
Explanation
The TLICS system scores three categories: Morphology, Neurology, and PLC integrity. Morphology: Burst fracture = 2 points. Neurological status: Intact = 0 points. PLC: Intact = 0 points. Total score = 2. A score of 3 or less indicates non-operative management. A score of 4 can be treated non-operatively or operatively based on surgeon preference/clinical scenario. A score of 5 or more favors operative treatment.
Question 385
Topic: Thoracolumbar Spine & Deformity
In a pediatric patient with an L5-S1 isthmic spondylolisthesis, which of the following spinopelvic parameters is typically fixed morphologically, significantly increased compared to the general population, and strongly correlates with progression of the slip?
Correct Answer & Explanation
. Pelvic incidence
Explanation
Pelvic incidence (PI) is a fixed morphological parameter unique to each individual, defined as the angle between a line perpendicular to the sacral plate and a line connecting the midpoint of the sacral plate to the center of the bicoxofemoral axis. Patients with developmental isthmic spondylolisthesis generally have a significantly higher PI. A high PI leads to an increased sacral slope and higher shear forces at the lumbosacral junction, predisposing to slip progression.
Question 386
Topic: Thoracolumbar Spine & Deformity
A surgeon is evaluating a 65-year-old man for a THA. Standing and sitting lateral spinopelvic radiographs are obtained. From the standing to the sitting position, the pelvic incidence minus lumbar lordosis (PI-LL) mismatch increases by 15 degrees, and the sacral slope decreases by 15 degrees. How would you categorize this patient's spinopelvic mobility?
Correct Answer & Explanation
. Normal spinopelvic mobility
Explanation
Normal spinopelvic mobility involves a decrease in sacral slope of 10 to 30 degrees when transitioning from standing to sitting, accommodating hip flexion by posterior pelvic tilt and reduction of lumbar lordosis.
Question 387
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?
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." Jimenez R, Lewis VO (eds): Culturally Competent Care Guidebook. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2007.
Question 388
Topic: Thoracolumbar Spine & Deformity
A 42 year-old-woman who underwent surgery for lumbar scoliosis 2 years ago now has fixed sagittal plane imbalance and severe back pain. Which of the following is considered a contraindication to isolated pedicle subtraction osteotomy for the treatment of iatrogenic flatback syndrome in this patient?
Correct Answer & Explanation
. Anterior pseudarthrosis
Explanation
Pedicle subtraction osteotomy is the preferred osteotomy technique for the treatment of many patients with iatrogenic flatback syndrome. In the presence of an anterior pseudarthrosis, however, it must be done in conjunction with an anterior procedure. Prior laminectomy is not a contraindication. Significant correction, usually averaging about 30 degrees, can be obtained through each osteotomy. Osteotomies should be performed at L2 or below in the presence of kyphosis at the thoracolumbar junction. The pedicle subtraction technique is preferred with vascular calcifications because it does not lengthen the anterior column, which could risk vascular injury. Potter BK, Lenke LG, Kuklo TR: Prevention and management of iatrogenic flatback deformity. J Bone Joint Surg Am 2004;86:1793-1808.
Question 389
Topic: Thoracolumbar Spine & Deformity
Figure 45 shows the lateral radiograph of a 19-year-old swimmer who has had back pain for the past 2 months. What is the most likely diagnosis?
Correct Answer & Explanation
. Spondylolysis
Explanation
The patient has a pars interarticularis defect of L5 without apparent listhesis. The other diagnoses are not present. Papanicolaou N, Wilkinson RH, Emmans JB, Treves S, Micheli LJ: Bone scintigraphy and radiography in young athletes with low back pain. Am J Roentgenol 1985;145:1039-1044.
Question 390
Topic: Thoracolumbar Spine & Deformity
Figure 3 shows the radiograph of an asymptomatic 10-year-old boy. Management should consist of
Correct Answer & Explanation
. periodic observation, but no activity restriction.
Explanation
Asymptomatic spondylolysis in a child or adolescent should be observed for the possible development of spondylolisthesis, but no other active intervention is needed.
Question 391
Topic: Thoracolumbar Spine & Deformity
A 12-year-old girl who is Risser stage 3 has had intermittent mild midback pain for the past 4 weeks. The pain is worse after prolonged sitting and after carrying a heavy backpack at school. She occasionally takes acetaminophen, but the pain does not limit sport activities. Examination reveals a mild right rib prominence during forward bending. Neurologic examination is normal. Radiographs show a 20-degree right thoracic scoliosis with no congenital anomalies or lytic lesions. Management should consist of
Correct Answer & Explanation
. back muscle stretching and reduced weight in the backpack.
Explanation
Mild scoliosis is not a painful condition, but it usually presents during adolescence. Intermittent back pain is reported by 25% to 30% of adolescents whether or not scoliosis is present. Such pain is often attributed to muscle strain from tight muscles, poor posture, or heavy school backpacks. The clinician must distinguish typical pain (mild, intermittent, nonlimiting) from atypical pain. The latter requires more careful examination and imaging studies (bone scan or MRI) to determine the source of pain. The patient's age and right thoracic curve pattern are typical for idiopathic scoliosis; therefore, imaging of the neuroaxis is not necessary to look for cord syrinx, tethering, or tumor. Brace treatment is not required for this small curve unless future progression is demonstrated. Ramirez N, Johnston CE, Browne RH: The prevalence of back pain in children who have idiopathic scoliosis. J Bone Joint Surg Am 1997;79:364-368. Hollingworth P: Back pain in children. Br J Rheum 1996;35:1022-1028.
Question 392
Topic: Thoracolumbar Spine & Deformity
A 19-year-old man has had back pain with activity, especially running in soccer and baseball, for the past 4 months. He denies any history of trauma. Examination reveals no motor weakness or sensory changes in the lower extremities. Range of motion shows increased pain with extension and mild limitation with flexion. A sitting straight leg raising test is limited at approximately 60 degrees bilaterally by back and buttocks pain. Plain radiographs are normal. MRI scans are shown in Figures 13a through 13e. What is the most likely diagnosis?
Correct Answer & Explanation
. Isthmic spondylolysis
Explanation
The patient has an isthmic spondylolysis. The plain radiographs are normal, but the MRI scans show increased marrow edema and signal at the L5 pars interarticularis. Findings of bilateral hamstring tightness and increased pain with extension over flexion suggests spondylolysis. The MRI scans do not show any signs of the other conditions. Wiltse LL, Rothman SL: Spondylolisthesis: Classification, diagnosis and natural history. Sem Spine Surg 1993;5:264-280.
Question 393
Topic: Thoracolumbar Spine & Deformity
Figure 6 shows the clinical photographs of a newborn who underwent a colostomy for an imperforate anus. Examination shows extended knees, flexed hips, and equinovarus feet. Dimpling is noted over the buttocks. Patients with these findings differ from patients with myelodysplasia in that they
Correct Answer & Explanation
. have protective sensation.
Explanation
The patient has sacral agenesis. Clinical signs include the classic dimpling over the buttocks and the characteristic lower extremity deformities. Imperforate anus is often associated with this disorder. Although motor function correlates with the level of vertebral defect, sensation is usually intact. This is important therapeutically, because patients are not as prone to pressure sores as are those with myelodysplasia. Kyphosis may develop in many patients with lumbosacral agenesis, but lordosis is unusual. Latex allergy and progressive neural deterioration may occur in patients with either myelodysplasia or sacral agenesis but is more common in the former.
Question 394
Topic: Thoracolumbar Spine & Deformity
A 16-year-old boy has abdominal and back pain after being involved in a high-velocity head-on motor vehicle accident. He was restrained in the rear of the automobile by a lap belt only. A radiograph and CT scan are shown in Figure 47. The patient has no other injuries. Optimal management should include
Correct Answer & Explanation
. cast immobilization in hyperextension for 6 weeks, followed by a thoracolumbosacral orthosis.
Explanation
Pediatric bony Chance fractures occur following severe flexion injuries as seen after motor vehicle accidents with lap belt restraints. There is a high rate of associated intra-abdominal injuries. In the absence of associated injuries, these fractures are best treated with immobilization. Bed rest is not necessary. Surgical fixation usually is not needed. Surgical stabilization and two-level fusion may be indicated in select individuals with progressive kyphosis of more than 25 degrees or other conditions that preclude cast or brace immobilization. Greenwald TA, Mann DC: Pediatric seatbelt injuries: Diagnosis and treatment of lumbar flexion-distraction injuries. Paraplegia 1994;32:743-751. Glassman SD, Johnson JR, Holt RT: Seatbelt injuries in children. J Trauma 1992;33:882-886.
Question 395
Topic: Thoracolumbar Spine & Deformity
A 19-year-old woman reports lower back pain following a motor vehicle accident. Radiographs obtained immediately after the accident and a bone scan obtained 4 weeks later are shown in Figures 25a through 25c. The patient asks questions regarding the cause, genetics, and natural history of her condition. She should be informed that the condition was
Correct Answer & Explanation
. preexisting to her accident, exists in 5% of the population, has a familial predisposition, and is unlikely to progress.
Explanation
The radiographs show L5 spondylolysis without spondylolisthesis (slip). The bone scan is normal, indicating that the pars interarticularis fractures are not acute. The incidence of spondylolysis is approximately 5% in the general population. The lesion generally develops in children age 5 to 6 years, and there is a second peak in the adolescent population. There is a familial predisposition, with reported rates of 27% to 69% in close relatives. A recent long-term follow-up study found that 90% of the spondylolisthesis had occurred before the patient's first visit to the physician. Spondylolisthesis tends to progress during the initial growth spurt and is similar in some respects to idiopathic scoliosis. Progression of a lytic spondylolysis to spondylolisthesis in adulthood has been reported; however, this is exceedingly rare. Lauerman WC, Cain JE: Isthmic spondylolisthesis in the adult. J Am Acad Orthop Surg 1996;4:201-208. Hensinger RN: Spondylolysis and spondylolisthesis in children and adolescents. J Bone Joint Surg Am 1989;71:1098-1107. Seitsalo S, Osterman K, Hyvarinen H, Tallroth K, Schlenzka D, Poussa M: Progression of spondylolisthesis in children and adolescents: A long-term follow-up of 272 patients. Spine 1991;16:417-421.
Question 396
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?
Correct Answer & Explanation
. A 4-year-old child with a fully segmented T10 hemivertebra and scoliosis that measures 50 degrees
Explanation
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 degrees), absence of kyphosis, concave growth potential, and appropriate age (younger than age 5 years).
Question 397
Topic: Thoracolumbar Spine & Deformity
A 14-year-old gymnast presents with chronic, mechanically reproducible low back pain. Radiographs reveal a pars interarticularis defect at L5 with a 30% anterior translation of L5 on S1. According to the Meyerding classification, what grade is this spondylolisthesis, and what is the primary initial management?
Correct Answer & Explanation
. Grade II; physical therapy and core strengthening
Explanation
The Meyerding classification grades the magnitude of slip based on the superior endplate of the vertebra below. Grade I: 0-25%, Grade II: 26-50%, Grade III: 51-75%, Grade IV: 76-100%, Grade V: >100% (spondyloptosis). A 30% slip is Grade II. The initial management for low-grade (I and II) isthmic spondylolisthesis without progressive neurologic deficit is non-operative, emphasizing activity modification, hamstring stretching, and core stabilization.
Question 398
Topic: Thoracolumbar Spine & Deformity
A 14-year-old female gymnast presents with chronic, progressive low back pain exacerbated by extension. Lateral radiographs demonstrate an isthmic spondylolisthesis at L5-S1.
In assessing her risk for continued slip progression, which spinopelvic parameter is considered the most predictive intrinsic biomechanical risk factor?
Correct Answer & Explanation
. A high Pelvic Incidence (PI)
Explanation
Pelvic incidence (PI) is a fixed morphological parameter unique to each individual (PI = Sacral Slope + Pelvic Tilt). A high pelvic incidence correlates with a more vertical orientation of the sacrum relative to the pelvis, which inherently increases the shear forces at the lumbosacral junction. Consequently, a high pelvic incidence is the most significant spinopelvic parameter predicting the risk of progression in pediatric and adolescent isthmic spondylolisthesis.
Question 399
Topic: Thoracolumbar Spine & Deformity
An 18-year-old gymnast complains of chronic lower back pain. Lateral radiographs demonstrate a pars interarticularis defect at L5 with an anterior translation of the L5 vertebral body over S1 by 60%. What is the appropriate Meyerding grade for this slip?
Correct Answer & Explanation
. Grade III
Explanation
The Meyerding classification system grades the severity of spondylolisthesis based on the percentage of forward translation: Grade I (0-25%), Grade II (26-50%), Grade III (51-75%), Grade IV (76-100%), and Grade V (>100%, Spondyloptosis). 60% falls into Grade III.
Question 400
Topic: Thoracolumbar Spine & Deformity
In the Meyerding classification of spondylolisthesis, a Grade III slip corresponds to a vertebral body displacement of:
Correct Answer & Explanation
. 25% to 50%
Explanation
The Meyerding classification grades the severity of spondylolisthesis based on the percentage of forward translation of the superior vertebral body over the inferior one. Grade I is 1-25%; Grade II is 26-50%; Grade III is 51-75%; Grade IV is 76-100%; Grade V (spondyloptosis) is >100%.
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