SPONDYLOLYSIS AND SPONDYLOLISTHESIS AFTER 5-LEVEL LUMBOSACRAL LAMINECTOMY FOR SELECTIVE POSTERIOR RHIZOTOMY IN CEREBRAL-PALSY

Of 163 children who have undergone five-level lumbosacral laminectomie s for selective posterior rhizotomy, 20% of those re-X-rayed post-oper atively (19/99) have developed incidental isthmic spondylolysis or gra de I spondylolisthesis. The majority of patients were ambulatory, acti ve, spastic diplegics. There were five children with isthmic defects a t L3-4, three at L4-5 and 11 at L5-S1. Six of the 19 children had grad e I spondylolisthesis, but none were symptomatic nor has there been an y evidence of further slipping to date. It is postulated that the lami nectomy, associated lordosis and increased mobility after rhizotomy ma y be factors in the causation.