The Effect of Smoking on the Fusion Rate of Spinal Fusion Surgery: A Systematic Review and Meta-Analysis.

Abstract

OBJECTIVE\nTo conduct a systematic review and meta-analysis comparing the fusion rate after spinal fusion surgery between smokers and nonsmokers.\n\n\nMETHODS\nWe searched PubMed, Embase, Cochrane Library, and Web of Science electronic databases through 10 March 2021 for cohort and case-control studies assessing the effect of smoking on the fusion rate of spinal fusion surgery. Two researchers independently screened the literature and extracted data according to the inclusion and exclusion criteria. Statistical analysis was performed using RevMan, version 5.4.\n\n\nRESULTS\nA total of 26 studies, including 4 case-control studies and 22 cohort studies, with 4409 patients, were included in the present meta-analysis. Follow-up was at least 6 months. Overall, the pooled results demonstrated that the fusion rate of smokers after spinal fusion was significantly lower than that of nonsmokers. The odds ratio was 0.55 (95% CI: 0.45-0.67, p<0.0001). Subgroup analyses by fusion level showed the adverse effect of smoking on the fusion rate at single-level (OR:0.61, 95%CI: 0.41-0.91, p=0.02) was more significant than that of multilevel (OR:0.55, 95%CI: 0.38-0.80, p=0.0010). Subgroup analysis according to the type of bone graft revealed an apparent association between smoking and fusion rate in the autograft subgroup (OR:0.47, 95%CI: 0.33-0.66, p<0.0001), but not in the allograft subgroup (OR:0.69, 95%CI:0.47-1.01, p=0.06).\n\n\nCONCLUSIONS\nThe fusion rate of smokers is significantly lower than that of non-smokers in spinal fusion surgery. Smokers should be encouraged to quit smoking to improve the outcome of spinal fusion surgery.