Abstract
In a prospective cohort study in 94 patients with 3 years' follow-up the efficacy of rigid and semi-rigid transpedicular instrumentation for lumbar spine fusion was evaluated via three established scores. Patient groups were similar in respect of anthropometric data. The indication for using the semi-rigid technique was a fairly stable intraoperative situation; for the more common unstable situations, the rigid technique was chosen. Selecting implant rigidity on these criteria led to results with an improvement rate well within the upper success range reported in the literature. Among people in employment, a lengthy preoperative sick leave was an important predictor for unsatisfactory outcome.