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New Findings about Spondylolysis in Young Athletes

This study looks at what happens to the spine when there's a spondylolysis on one side. Spondylolysis is a stress reaction or fracture of the pars interarticularis, a thin section in the back of the vertebral bone.

The defect is thought to be a fatigue fracture. Repeated loading and unloading of this region from physical activity may cause it. Anyone with a pars defect on both sides can progress to spondylolisthesis, a slippage of the vertebral body forward over the vertebrae below it.

But what happens when the defect is only on one side? According to researchers at the Spine Research Center (University of Toledo, Ohio), one-sided (unilateral) spondylolysis can lead to a fracture on the other side. Increased stress in the area may be the cause.

The scientists used a computer model to analyze CT scans. Thirteen young athletes with unilateral spondylolysis were included. The results showed the stress reaction increased on the opposite side of the spondylolysis. The stress increased with all lumbar motions, especially spinal rotation.

Changes were seen in more than half of the cases. This took place slowly as the defect got worse. The authors warn surgeons of these possible changes and the increased risk of fracture in active athletes. Young patients with unilateral spondylolysis should be watched very carefully.

References: Koichi Sairyo, MD et al. Athletes with Unilateral Spondylolysis are at Risk of Stress Fracture at the Contralateral Pedicle and Pars Interarticularis. A Clinical and Biomechanical Study. In The American Journal of Sports Medicine. April 2005. Vol. 33. No. 4. Pp. 583-590.

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