The effects of bisphosphonates on osteoporotic patients after lumbar fusion: a meta-analysis

PURPOSE: We conducted a meta-analysis of controlled clinical trials to evaluate the efficacy of bisphosphonates in lumbar fusion. INTRODUCTION: Bisphosphonates reduce bone resorption and remodeling by osteoclast activity inhibition, inactivation, and apoptosis. However, it remains controversial whether bisphosphonate therapy affects spinal fusion. METHODS: We searched MEDLINE, Cochrane CENTRAL, ScienceDirect, EMBASE, and Google Scholar to identify studies reporting the effects of bisphosphonates on osteoporotic patients after lumbar fusion. Secondary sources were identified from the references of the included literature. Pooled data were analyzed using RevMan 5.1. RESULTS: Seven studies met the inclusion criteria. There were significant differences in solid intervertebral fusion (RD=0.07, 95% CI: −0.00 to 0.15, P=0.05), subsequent VCFs (RD=−0.21, 95% CI: −0.30 to −0.12, P<0.00001), pedicle screw loosening (RD=−0.17, 95% CI: −0.28 to −0.05, P=0.006), and cage subsidence (RD=−0.25, 95% CI: −0.42 to −0.07, P=0.005) between two groups. No significant differences between two groups were found regarding implant fixation failure (RD=−0.06, 95% CI: −0.22 to 0.10, P=0.48). CONCLUSION: This meta-analysis showed that bisphosphonates may increase solid intervertebral fusion and decrease subsequent VCFs, pedicle screw loosening, and cage subsidence.