What is spondylolisthesis?
Spondylolisthesis (spon + dee + lo + lis + thee + sis) is a condition of the spine whereby one of the vertebra slips forward or backward compared to the next vertebra. Forward slippage of one vertebra on another is referred to as anterolisthesis, while backward slippage is referred to as retrolisthesis. Spondylolisthesis can lead to a deformity of the spine as well as a narrowing of the spinal canal (central spinal stenosis) or compression of the exiting nerve roots (foraminal stenosis).
What causes spondylolisthesis?
There are five major types of lumbar spondylolisthesis.
- Dysplastic spondylolisthesis: Dysplastic spondylolisthesis is caused by a defect in the formation of part of the vertebra called the facet that allows it to slip forward. This is a condition that a patient is born with (congenital).
- Isthmic spondylolisthesis: In Isthmic spondylolisthesis, there is a defect in a portion of the vertebra called the pars interarticularis. If there is a defect without a slip, the patient has spondylolysis. Isthmic spondylolisthesis can be caused by repetitive trauma and is more common in athletes exposed to hyperextension motions including gymnasts, and football linemen.
- Degenerative spondylolisthesis: Degenerative spondylolisthesis occurs due to arthritic changes in the joints of the vertebrae due to cartilage degeneration. Degenerative spondylolisthesis is more common in older patients.
- Traumatic spondylolisthesis: Traumatic spondylolisthesis is due to direct trauma or injury to the vertebrae. This can be caused by a fracture of the pedicle, lamina or facet joints that allows the front portion of the vertebra to slip forward with respect to the back portion of the vertebra.
- Pathologic spondylolisthesis: Pathologic spondylolisthesis is caused by a defect in the bone caused by abnormal bone, such as from a tumor