Survivorship analysis of pedicular fixation systems in the treatment of degenerative disorders of the lumbar spine: a comparison of Cotrel-Dubousset instrumentation and the AO internal fixator

Abstract

We retrospectively analyzed the frequency and clinical consequences of pedicular fixation system failure in 50 patients who underwent Cotrel-Dubousset transpedicular instrumentation (CDI), and 46 patients who underwent AO internal fixator (IF) instrumentation for similar indications. After 2 years, 14 implants in the CDI group and 13 in the IF group had failed. The overall probability of implant survival was similar in both groups (CDI, 71.9% versus IF, 71.7%). However, more implant failures were associated with nonunion, loss of reduction, and nerve-root compromise in the IF group (four versus none) than in the CDI group. Implant failure usually occurred after solid fusion, and did not significantly affect the short-term clinical results. Therefore, implant failure does not a priori indicate failure of the operation.