Preoperative epidural steroid injections do not increase the risk of postoperative infection in patients undergoing lumbar decompression or fusion: a systematic review and meta-analysis

Purpose Epidural corticosteroid injections (ESI) are a mainstay of nonoperative treatment for patients with lumbar spine pathology. Recent literature evaluating infection risk following ESI after elective orthopedic surgery has produced conflicting evidence. Our primary objective was to review the literature and provide a larger meta-analysis analyzing the temporal effects of steroid injections on the risk of infection following lumbar spine surgery. Methods We conducted a query of the PubMed, Embase, and Scopus databases from inception until April 1, 2022 for studies evaluating the risk of infection in the setting of prior spinal steroid injections in patients undergoing lumbar spine decompression or fusion. Three meta-analyses were conducted, (1) comparing ESI within 30-days of surgery to control, (2) comparing ESI within 30-days to ESI between 1 and 3 months preoperatively, and (3) comparing any history of ESI prior to surgery to control. Tests of proportions were utilized for all comparisons between groups. Study heterogeneity was assessed via forest plots, and publication bias was assessed quantiatively via funnel plots and qualitatively with the Newcastle-Ottawa Scale. Results Nine total studies were included, five of which demonstrated an association between ESI and postoperative infection, while four found no association. Comparison of weighted means demonstrated no significant difference in infection rates between the 30-days ESI group and control group (2.67% vs. 1.69%, p = 0.144), 30-days ESI group and the > 30-days ESI group (2.34% vs. 1.66%, p = 0.1655), or total ESI group and the control group (1.99% vs. 1.70%, p = 0.544). Heterogeneity was low for all comparisons following sensitivity analyses. Conclusion Current evidence does not implicate preoperative ESI in postoperative infection rates following lumbar fusion or decompression. Operative treatment should not be delayed due to preoperative steroid injections based on current evidence. There remains a paucity of high-quality data in the literature evaluating the impact of preoperative ESI on postoperative infection rates.