Posterior inter-body fusion in lumbar spine surgery: A systematic review

BackgroundPosterolateral fusion (PLF) is a common method for achieving fusion in lumbar spine surgery. Posterior lumbar inter-body fusion (PLIF) has been reported to give a higher fusion rate and a better functional and clinical outcome.ObjectivesThe objective of the review was to determine whether PLIF is more effective than PLF in improving clinical and radiological outcomes in adults surgically treated for degenerative lumbar spine conditions.MethodsElectronic databases, bibliographies and relevant journals were searched systematically, and a meta-analysis was conducted.ResultsOf 2798 citations identified, five studies met our inclusion criteria; none was a randomized controlled trial. A total of 148 patients had undergone PLIF (intervention) and 159 PLF (control). Pooled meta-analyses showed that non-union rates were lower in the intervention group (relative risk (RR), 0.22; 95% confidence interval (CI), 0.08–0.62). The intervention group had significantly heavier disc height (weighted mean difference, 3.2 mm; 95% CI, 1.9–4.4) and less residual percentage slippage (weighted mean difference, 6.3%; 95% CI, 3.9–8.7) at final follow-up. No significant difference in segmental or total lumbar lordosis was seen. Because of the heterogeneity of the results, no conclusion could be drawn about the functional benefits of the two procedures.ConclusionThis review suggests that PLIF results in a higher fusion rate and better correction of certain radiographic aspects of deformity than PLF. It also showed a slight but nonsignificant trend towards a better functional outcome with PLIF. The lack of randomized controlled trials and the methodological limitations of the available studies indicate the need for a sufficiently large, methodologically sound study with clinically relevant outcome measures. Until this has been done, the evidence for the beneficial effects of posterior inter-body fusion should be interpreted with caution.