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Radiology Cases |
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Radiology Cases |
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Spondylolysis |
Introduction
Cervical spondylolysis was reported less than 100 times in the English language since 1951 (1). It may be defined as a well corticated congenital defect that is between the superior and inferior articular processes of respective cervical segments (2). It is considered a relatively rare condition with questionable clinical significance. However, as the potential for instability exists, flexion/extension radiographs are mandated to evaluate for segmental hypermobility or instability (3).
Note: From this point on, references to "spondylolysis" should be regarded as "lumbar spondylolysis."
Spondylolysis is a defect of the pars interarticularis that affects mostly the lower lumbar vertebrae of almost one person in 20. Usually, there is a complete break in the pars on one or both sides of the neural arch. The condition often is asymptomatic but may be painful in those who participate in sports (4). Bilateral spondylolysis can allow a forward slip of the superior vertebra relative to the one below, and this condition, spondylolisthesis, often is associated with chronic pain and disability (5).
Types of spondylolysis:
Note: Spondylolysis was never reported in stillborn fetuses or in newborns, therefore, it should be considered an acquired condition (6), however, familial occurrence of spondylolytic patients and the high incidence of spina bifida indicate the significance of congenital or developmental predisposition (7).
Case Report
Discussion
A fatigue fracture of the pars interarticularis can occur during normal flexion and extension loading. These forces may be accentuated by extremes of posture, such as during a back walkover in gymnastics. The sequence of events is (8):
Primary care practitioners should be familiar with the progression of spondylolysis and its progression from pars interarticularis stress fracture to spondylolysis and to spondylolisthesis. One-half of all pediatric back pain in athletic patients is related to disturbances of the posterior elements including spondylolysis. This presents as low back pain aggravated by activity, and frequently has minimal physical findings. Failure to suspect, hence to diagnose, a pars stress fracture or early spondylolysis is common and a misdiagnosis of lumbosacral strain is often made. A complicating factor in early diagnosis is the fact that plain radiographs, even with oblique films, may not be helpful at the stress fracture stage, and other imaging techniques (bone scan possibly with single photon emission computed tomography [SPECT]) must be used early in the diagnostic process. In the primary care setting, an early diagnosis of posterior element involvement in low back pain either at the stage of pars stress fracture or early spondylolysis can prevent progression of the disease and the need for aggressive intervention for a more significant defect (9).
Lateral oblique radiographs are considered important for the identification of spondylolytic lesions, but these projections will give a clear view only when the radiological beam is in the plane of the defect. In a study by Saifuddin et al. (10), it is suggested that CT scans with reverse gantry angle are now more appropriate than oblique radiography for the assessment of spondylolysis.
The treatment of spondylolysis depends on the severity of clinical symptoms, pathologic anatomy, and prognosis. Simple spondylolysis can be cured by immobilization alone in selected cases, or by surgery when it remains symptomatic and resistant to nonoperative treatment. The majority of the cases are asymptomatic and require no treatment (6).
When spondylolysis progresses into spondylolisthesis, indications for treatment are pain, radiculopathy, gait disturbance with hamstring contracture, and cosmetic dissatisfaction. In the presence of a horizontal sacrum, initial treatment is conservative with rest, orthotic management, and an exercise program (6). In many cases this is successful, and once the patient becomes asymptomatic, the brace can be discontinued and normal activity resumed. Radiographic follow-up is indicated at least yearly to detect any evidence of progression. Should conservative treatment fail, with persistence or worsening of pain, hamstring spasm, or radiculopathy, surgical treatment is indicated to stabilize the spondylolisthesis and prevent further slippage. In the presence of vertical sacrum and symptoms, progression is almost certain, and bracing generally has been ineffective in resolving the symptoms. These cases are indicated for surgical treatment sooner rather than later (6).
There are several geometric measurements that constitute a detailed quantitative description of the condition (11). According to Panjabi and White (12) these measurements are useful for monitoring spinal changes and, in some cases, they can be used as prognostic indicators. Panjabi and White (12) believe that the percentage of anterior translation and sagittal rotation are the most important parameters. These authors also stated that the measurements that can help predict the progression of deformity are: percent rounding of the top of the sacrum, wedging of the displaced L5 vertebra, lumbar lordosis, and a large sacrohorizontal angle. These parameters tend to indicate geometric relationships that, in the standing position, would maximize gravitational loading vectors and increase deformity.
References
