Thoracolumbar Spine & Deformity MCQs

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 suggest spondylolysis. The MRI scans do not show any signs of the other conditions.

DISCUSSION: 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. REFERENCE: Renshaw TS: Sacral agenesis. J Bone Joint Surg Am 1978;60:373-383.

The patient has diskitis. Administration of IV antibiotics speeds resolution and minimizes recurrence. Bed rest and cast immobilization have been successfully used to treat this disorder but can be associated with prolonged recovery and frequent recurrence, even when oral antibiotics are administered. A perivertebral abscess seen in association with this condition usually resolves without surgery.(SBQ12SP.92) A 36-year-old man presents to the emergency department after being involved in a motor vehicle collision. He is complaining of back pain and imaging shows the findings in Figure A. On neurological examination, he does not have any deficits. MRI shows approximately 25% canal encroachment and no evidence of injury to the posterior ligamentous complex. Which of the following is the most appropriate course in management?Review TopicStrict bedrest for six weeks then progressive weightbearingAmbulation as tolerated with or without a TLSOSurgical decompression and anterior stabilizationSurgical decompression and posterior stabilizationSurgical decompression and combined anterior/posterior stabilizationThe patient has a L1 burst fracture with minimal retropulsion of bony fragments in the spinal canal. In the absence of neurological deficits and injury to the PLC, the most appropriate treatment is ambulation as tolerated with or without a thoracolumbrosacral orthosis (TLSO).Thoracolumbar burst fractures are typically caused by an axial load with flexion and commonly found in this location due to increased motion at these segments. With an intact posterior ligamentous complex (PLC) and no neural compromise, TLSO is the mainstay of treatment. If there is evidence of neurological deficit and/or PLC injury, decompression and fusion are indicated. The degree of acceptable kyphosis is controversial. The choice of anterior versus posterior approach is based on ease of decompression.Vaccaro et al. introduced a new classification system for thoracolumbar injuries, TLICS, based on morphological appearance, integrity of the posterior ligamentous complex, and neurological status. They advocate use of the system for nonoperative versus operative decision making and communication between surgeons.Bailey et al. completed a randomized, nonblinded controlled trial to determine theefficacy of bracing for AO type A0-A3 thoracolumbar burst fractures. Both groups were encouraged to ambulate as tolerated and the no brace group had bending restrictions for 8 weeks. They found no difference in the Roland Morris Disability Questionnaire (RMDQ) score at 3 months after injury.Figure A is sagittal CT scan of the lumbar spine showing a burst fracture of L1 with minimal retropulsion. Illustration A is the TLICS classification with score of 4 being the branch point for nonoperative versus operative management.Incorrect Answers:

Pediatric bony Chance fractures occur following severe flexion injuries as seen after motor vehicle accidents with lap belt restraints. In the absence of associated injuries, these fractures are best treated with immobilization.

DISCUSSION: 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. REFERENCES: 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. Fredrickson BE, Baker D, McHolik WJ, Yuan HA, Lubicky JP: The natural history of spondylolysis and spondylolisthesis. J Bone Joint Surg Am 1984;66:699-707.

DISCUSSION: The radiographic findings are consistent with a type II Hangman’s fracture or traumatic spondylolisthesis of C2. This occurs with more than 3 mm of displacement according to the classification of Levine and Edwards. Even though the radiograph reveals significant displacement, the overall space available for the neural elements is increased, therefore minimizing the risk of neural compromise. Neurologic injury is most frequently encountered in type III injuries that are associated with bilateral facet dislocations of C2 on C3 but is infrequent in type I (less than 3 mm displacement) and type II traumatic spondylolisthesis. When neurologic deficits are associated with type II injuries, it is usually the result of an associated head injury. Cruciate paralysis occurs as a result of the crossover of the motor and sensory tracts at different levels of the cord at the C1-C2 junction. This results in normal sensation but complete loss of motor function.

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.

DISCUSSION: 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. REFERENCES: Wood K, Butterman G, Mehbod A, et al: Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit: A prospective, randomized study. J Bone Joint Surg Am 2003;85:773-781. Shen WJ, Liu TJ, Shen YS: Nonoperative treatment versus posterior fixation for thoracolumbar junction burst fractures without neurologic deficit. Spine 2001;26:1038-1045.

Adult idiopathic scoliosis and adult "de-novo" scoliosis can present with a number of symptoms that relate to associated degenerative findings such as stenosis or spondylolisthesis. In the absence of these associated conditions, increased levels of pain in patients with scoliosis has been found to most closely correlate with sagittal imbalance. Thoracolumbar and lumbar curves and thoracolumbar kyphosis have both been found to closely correlate with increased symptoms and lower health-related quality of life (HRQL) outcome scores. Thoracic scoliosis, thoracic hypokyphosis, lumbar hyperlordosis, and lumbar disk degeneration have not been found to correlate with increased symptoms.

Discussion: Asymptomatic spondylolysis in a child or adolescent should be observed for the possible development of spondylolisthesis, but no other active intervention is needed. The initial treatment of choice for symptomatic spondylolysis includes rest and activity modifications, nonsteroidal anti-inflammatory drugs, physical therapy, bracing, and casting. Immobilization with a TLSO or pantaloon spica cast may permit healing of an acute pars fracture. Rarely, surgical treatment may be necessary. Surgical options include posterolateral L5-S1 fusion or direct repair of the pars defect.

DISCUSSION: Circumferential fusion is the preferred choice for patients undergoing revision surgery following failed posterolateral fusions for isthmic spondylolisthesis as well as for those patients having primary surgery for high-grade isthmic spondylolisthesis.

DISCUSSION: According to the classification of Levine and Edwards, a type I Hangman’s fracture is minimally displaced without angulation and represents a stable injury. Good clinical success has been achieved with nonsurgical management consisting of use of a rigid collar until the patient reports pain relief, followed by quick mobilization. REFERENCE: Levine AM, Edwards CC: The management of traumatic spondylolisthesis of the axis. J Bone Joint Surg Am 1985;67:217-226.

Adult patients with isthmic spondylolisthesis most commonly have neurologic symptoms due to foraminal stenosis at the level of the spondylolisthesis. In this scenario, the patient is most likely to have weakness of the L5 myotome, which would cause weakness of the extensor hallucis longus.

Spondylolisthesis can be classified into five types. Type I, dysplastic, occurs at the lumbosacral junction as a result of congenital abnormalities of the upper sacrum and/or the arch of L5. Type II, isthmic, refers to those involving a lesion in the pars interarticularis. Type IIA, lytic, represents fatigue fractures of the pars. Type IIB describes those with elongated, but intact pars. Type IIC describes those that are a result of an acute fracture of the pars. Type III, degenerative spondylolisthesis, results from long-standing intersegmental disease. Type IV, traumatic, refers to those resulting from fractures in regions other than the pars, such as the pedicles. Type V, pathologic, refers to spondylolisthesis resulting from generalized or local bone disease. The radiographs demonstrate type II, isthmic spondylolisthesis.

The 'Scottie dog with a collar' sign on an oblique lumbar radiograph represents a radiolucent defect in the pars interarticularis, indicating spondylolysis. This injury is a stress fracture resulting from repetitive hyperextension, commonly seen in young athletes like gymnasts and football linemen.

Pelvic Incidence (PI) is a fixed morphological parameter representing the relationship between the sacrum and the femoral heads, defined by the equation PI = PT + SS. In conditions like flatback syndrome where there is a loss of lumbar lordosis, the patient shifts their center of gravity anteriorly. To compensate and bring the center of gravity back over the pelvis, the patient retroverts the pelvis. Pelvic retroversion corresponds to an increase in Pelvic Tilt (PT). Because PI is a constant, an increase in PT mathematically and anatomically mandates a decrease in Sacral Slope (SS).

The Thoracolumbar Injury Classification and Severity (TLICS) score determines treatment based on three categories: 1) Morphology: Burst fracture = 2 points. 2) Neurologic status: Intact = 0 points. 3) PLC integrity: Indeterminate (suspected) = 2 points. Total score = 2 + 0 + 2 = 4 points. According to TLICS, a score of ≤ 3 suggests nonoperative management, a score of ≥ 5 suggests operative management, and a score of exactly 4 is an equivocal indication where either operative or nonoperative management may be chosen based on surgeon preference and patient factors.

In L5-S1 isthmic spondylolisthesis, the pars interarticularis defect leads to anterior translation of L5 on S1. The fibrocartilaginous tissue at the pars defect (Gill nodule) and the slipping of the L5 vertebra cause compression of the exiting L5 nerve root within the neural foramen. This is in contrast to degenerative spondylolisthesis, where the traversing root is typically compressed in the lateral recess.

The TLICS scoring system dictates treatment based on morphology, neurologic status, and PLC integrity. Morphology: Burst fracture = 2 points. Neurologic 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 is the watershed (operative vs. non-operative), and 5 or more indicates operative intervention.

Reduction of high-grade L5-S1 isthmic spondylolisthesis carries a significant risk of iatrogenic L5 nerve root injury. This occurs due to stretching of the L5 nerve root as the L5 vertebral body is pulled posteriorly and superiorly during the reduction maneuver. The L5 nerve is tethered by the lumbosacral ligament and can be stretched over the sacral ala. S1 nerve root injury is less common during the actual reduction maneuver.