Clinical History
A fourteen year old boy presents with a six week history of low back pain. The pain was intermittently present, but now is present at rest. Examination revealed a limited range of back motion with no localised tenderness. The patient’s main complaint is that he is unable to bowl at cricket as fast as he would like.
Scan Findings
The planar bone scan (Figure One) demonstrates a typical fracture of the pars interarticularis and this is confirmed on the tomographic or SPECT images in Figure Two.
Discussion
Back pain in an otherwise well adolescent athlete may be caused by many conditions but the condition to exclude is a pars interarticularis fracture as this may contribute to nearly 50% of cases of back pain in athletes. The fracture is thought to be due to repetitive hyperextension of the posterior elements of the spine. The fast bowler is the typical candidate for a pars fracture, but other sports such as gymnastics, football and weightlifting are also implicated. Not only is the diagnosis important, but there is evidence that early intervention may improve long term outlook. Untreated this condition predisposes the patient to a spondylolisthesis and chronic back pain. Unfortunately There is no universally accepted treatment for this condition. Most authorities would recommend stopping the sport, analgesia and physiotherapy focussing on flexion activities, hamstring stretching and core strengthening. The condition can take up to nine to twelve months to fully resolve. Conclusion
The test of choice for the diagnosis of a pars fracture is a bone scan. Plain radiographs and MRI are relatively insensitive in the diagnosis of this condition. CT has a better sensitivity than plain radiographs and MRI but cannot differentiate an acute from an old fracture.
Reference:
Cassas KJ et al. Childhood and Adolescent Sports-Related Overuse Injuries. Amer Fam Phys 2006; 73:1014-22
Case Study submitted by
Patrick Butler
Department of Nuclear Medicine,
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Figure 1. Posterior view of lumbar spine bone scan with focal uptake in posterior aspect of left L4 vertebra.
Figure 2. Tomographic (SPECT) images showing focal uptake in pars interarticularis region of left L4 vertebra.
