> Patient and Family > Spondylolysis / Spondylolisthesis
If the fracture gap at the pars widens, then the condition is called Spondylolisthesis. Widening of the gap leads to the fifth lumbar vertebra shifting forward on the part of the pelvic bone called the sacrum. Normally, the pars interarticularis stabilizes a bony hook that keeps the L5 vertebra from sliding downhill on S1. If the fracture removes this stability, the bone may move forward to varying degrees. Standing lateral spine X-rays are measured to determine the amount of forward slippage. Symptoms may include low back pain or pain in the buttocks or legs related to irritation of the nerve roots. This type of spondylolisthesis is called “Isthmic” when the chronic fracture leads to the slippage. Another common type of spondylolisthesis in adults is called “degenerative spondylolisthesis”.