Timing Matters: Preoperative Lumbar Epidural Steroid Injection and Long-Term Outcomes Following Single-Level Posterior Lumbar Fusion

Study Design Retrospective Cohort Analysis. Objective CESIs are a mainstay of nonoperative treatment for degenerative lumbar spine disease. As increasing numbers of patients undergo sPLF after receiving CESIs, understanding their impact on surgical outcomes is essential. The objective of the present investigation was to evaluate the association between preoperative corticosteroid epidural spinal injections (CESI) and postoperative outcomes following single-level posterior lumbar fusion (sPLF). Methods A retrospective cohort study was performed using the TriNetX database. Patients undergoing sPLF were stratified by preoperative CESI exposure within 3 months of surgery. After 1:1 propensity score matching, 3,804 patients remained in each cohort. Outcomes included surgical site infection (SSI), pseudoarthrosis, and reoperation. Risk ratios (RR), 95% confidence intervals (CI), and Kaplan-Meier analyses were performed. Results Preoperative CESI was not associated with an increased risk of 90-day SSI (1.06% vs. 1.01%; RR 1.05, 95% CI 0.68–1.64; p=0.82). However, pseudoarthrosis occurred more frequently in the CESI cohort at 1 year (9.58% vs. 6.54%; RR 1.47; p<0.001), 3 years (11.20% vs. 7.55%; RR 1.48; p<0.001), and 5 years (11.81% vs. 8.10%; RR 1.46; p<0.001). Reoperation rates were not significantly different at 5 years (7.81% vs. 7.25%; RR 1.08; p=0.36). Kaplan-Meier analysis demonstrated earlier and sustained pseudoarthrosis following preoperative CESI. The number needed to harm was 33. Conclusions Preoperative CESI within 3 months of sPLF was associated with increased long-term pseudoarthrosis, without increasing postoperative SSI and reoperation rates.