For children without the predisposition, performing the same activities does not cause a stress fracture. Similarly, if the child with the predisposition never performed extension of the spine, the pars defect would never occur. Isthmic spondylolisthesis has never been detected in non-ambulatory patients. Degenerative spondylolisthesis is a forward slippage secondary to arthritis of the spine. Spinal stenosis is highly associated with this process.
Motion therefore occurs on a microscopic level.
The most common region for degenerative spondylolisthesis is L4-5. Traumatic spondylolisthesis is a slippage caused by a fracture in the spine, usually at the facet joint. The disruption of the bone allows the slippage. This is seen, for instance, in patients with stenosis who have a very wide decompression and too much of their joints in back are taken out, leaving them with an unstable spine. All rights reserved.