Posterior Lumbar Interbody Fusion with Threaded Fusion Cage: Long-term Follow-up Results

ABSTRACT

OBJECTIVES: Of all fusion techniques in the lumbar spines, PLIF has the best theoretical opportunity in achieving spinal fusion by way of load sharing effect of the anterior column but it is taken to be a technically demanding procedure and frequent problems have been reported. Threaded Fusion Cage(TFC) has been used as a substitute for autologous bone grafts during posterior lumbar interbody fusion in degenerative lumbar diseases since 1992. The purpose of this study is to evaluate the long-term efficacy of TFC in achieving a spinal fusion and the clinical outcome. METHODS: Total 597 patients underwent PLIF with TFC using laminectomy bone chips as bone graft during the last 7 years. Among them, 351 patients could be followed-up for more than 3 years and their clinical and radiographic data were reviewed retrospectively. Total 497 segments of PLIF with TFC were done in those 351 patients, their mean follow-up period were 59.8+/-9.1 months. RESULTS: The clinical success according to Prolos scale were achieved in 83.2% of the patients. When observed according to the disease entities, however multiple spondylotic stenosis patients showed significantly less favorable outcome(p<0.05). In the radiologic evaluation, bony fusion was achieved in 92.0% but when observed according to the disease entities, the fusion rate was significantly lower in the spondylolytic spondylolisthesis patients(p<0.05). CONCLUSION: The PLIF with TFC has been found to be an effective and safe procedure for lumbar spine fusion, demonstrating a high fusion rate and clinical success with rare complications. In addition, using the laminectomy bone chips as the bone graft in the TFC seemed to provide successful bony fusion without further invasive and painful procedure to obtain iliac bone graft.