In this study of 100 cases in which a herniated nucleus pulposus was removed, all patients had sciatic pain, and, with one exception, all had back pain, preceding or coincident with the sciatica. Roentgenographic or clinical examination revealed an unstable lumbosacral joint in eighty-four cases. A spine fusion was done at the time of removal of the herniated nucleus in eighty-three cases. The results in seventy cases with complete records one year or more after operation were twenty-four excellent, thirty-three good, thirteen poor.