Abstract
To find out if we can predict postoperative instability before an operation, we measured the preoperative radiographic factors we proposed for inducing spondylolisthesis. Thirty-three patients who underwent lumbar decompression without fusion for acquired lumbar spinal canal stenosis between 1983 and 1997 were included in this study. The mean time of the postoperative observation was 30 months. Degenerative spondylolisthesis was seen in 14 patients. Postoperative slipping was seen in 5 patients. We found no relationship between each preoperative radiographic factor and the progression of slipping after lumbar decompression. Postoperative slipping had a tendency to increase if a preoperative narrowing of the disc space was present. We concluded that it is difficult to predict postoperative slipping by preoperative roentgenogram.
