The long-term effect of posterolateral fusion in adult isthmic spondylolisthesis: a randomized controlled study

Posterolateral fusion in adult lumbar isthmic spondylolisthesis results ina modestly improved long-term outcome compared with a 1-year exercise program. Although the results show that some of the previously reported short-term improvement is lost at long term, patients with fusion still classify their global outcome as clearly better than conservatively treated patients. Furthermore, because the long-term outcome of the patients conservatively treated most likely reflects the natural course, one can also conclude that no considerable spontaneous improvement should be expected over time in adult patients with symptomatic isthmic spondylolisthesis. Substantial pain, functional disability and a reduced quality of life will in most patients most likely remain unaltered over many years.