What is spondylolysis?
Spondylolysis is a stress reaction or stress fracture that develops in one or both pars interarticularis of the lumbar spine. The majority of cases are young athletes whose sport involves repetitive flexion, extension, or rotation of the spine. This is typically seen in dancers, gymnasts, swimmers, baseball, tennis, and volleyball players. Although usually an overuse injury, spondylolysis may present following an acute overload. If the defect is present on both sides of the pars interarticularis, this can lead to spondylolisthesis, which means anterior displacement of the vertebral body due to bilateral defects in the vertebrae.

Unless a moderate fracture or vertebral displacement is present, x-rays are usually negative. With a positive exam including vertebral point tenderness, pain with back extension, and a positive stork test, an MRI is indicated to rule out a stress reaction or fracture. It is important to obtain a specific MRI with the appropriate sequences to pick up bone marrow edema in the pars interarticularis. Treatment includes a back brace to avoid back extension, physical therapy for core strength, and most importantly, complete cessation of all sports until the injury has healed. The length of treatment is typically 3 months, but may be longer based on fracture severity.