Anomalous lumbosacral nerve roots associated with spondylolisthesis.

Anomalies of the lumbosacral nerve roots, if unrecognized, may lead to injury of that nerve in operations on lumbar disks. Myelography rarely predicts the anomaly before operation. However, the presence of congenital skeletal defects of the lumbosacral joint should alert the surgeon to the possibility of anomalous nerve roots. Two cases of spondylolisthesis of the lumbosacral joint with with associated nerve root abnormalities are presented.