Degenerative spondylolisthesis.

Degenerative spondylolisthesis is one important type of spinal stenosis. The spinal canal stenosis varies in degree. This is the result of anterior slipping of the whole vertebra, usually L4 on L5. The clinical picture is not greatly different from that observed in the other types of lumbar canal stenosis. The surgical management involves decompression of the cauda equina by laminectomy. Often this is associated with arthrectomy to decompress the nerve roots. Extensive excision of the neural arch may result in further spinal instability for which spinal fusion is generally advisable.