A condition called can also cause the slippage that happens with spondylolisthesis. Spondylolysis is a defect in the bony ring of the spinal column. It affects the pars interarticularis, mentioned above. This defect is most commonly thought to be a "stress fracture" that happens from repeated strains on the bony ring. Participants in gymnastics and football commonly suffer these strains. Spondylolysis can lead to the spine slippage of spondylolisthesis when a fracture occurs on both sides of the bony ring. The back section of the bony ring separates from the main vertebral body, so the injured vertebra is no longer connected by bone to the one below it. In this situation, the facet joints can't provide their normal support. The vertebra on top is then free to slip forward over the one below.
Spondylolysis and spondylolisthesis are conditions affecting the joints that align the vertebrae one on top of the other. Spondylolysis is a weakness or stress fracture in the facet joint area. This weakness can cause the bones to slip forward out of normal position, called spondylolisthesis, and kink the spinal nerves. Treatment options include physical therapy to strengthen the muscles. A back brace may be used to support the spine. In some cases, surgery can realign and fuse the bones.
Adult Spondylolisthesis in the Low Back
Spondylolisthesis is a forward slip of one vertebra on top of another (which can occur at any level) resulting in a pinched nerve. Spondylolisthesis is classified as developed or acquired. Developed happens over time from an abnormal architecture of the spine. Acquired spondylolisthesis occurs after a significant injury and is graded I through IV. Spondyloptosis is a vertebra that has completely slipped over the edge of the lower vertebra. There are several causes for the slip. Some slips are due to simple wear and tear of the bone, others are due to injury. Sometimes a hairline fracture allows vertebrae to slip forward on top of each other. Still others are thought to be related to inherited bone variations. The more significant the slip the more likely the fusion will all require instrumentation.
Other reasons for spinal fusion include treatment of a fractured (broken) vertebra or correction of a deformity.