The Impact of Preoperative Spinal Injection Timing on the Postoperative Complications of Lumbar Fusion

OBJECTIVE: To determine the impact of epidural spinal injections (ESIs) on postoperative surgical complications. METHODS: This retrospective all-payer database analysis identified 202,181 adult patients undergoing one- to three-level transforaminal lumbar interbody fusion (TLIF) from 2010 to 2020. A 1:1 exact matching on comorbidities and demographics was performed, creating 2 cohorts: 1) patients who received an ESI within 90 days of surgery and 2) patients who did not receive an ESI. The primary outcome was surgical complication rates between groups at 30 days postoperatively. For the secondary outcome, patients were stratified based on injection time before surgery: 1-30, 31-45, 46-60, 61-75, and 76-90 days. Logistic regression was performed between groups to identify temporal associations of complication rates. The P value was set to 0.05 for the primary analysis, and the Bonferroni correction was utilized for the secondary outcome. RESULTS: Exact matching produced 12,491 pairs for analysis. Groups were well-matched on demographics, comorbidities, and fusion levels. The 30-day postoperative rates of surgical complications, hematomas, wound disruptions, or surgical site infections did not differ between groups (P> P > 0.05). The rate of cerebrospinal fluid (CSF) leak was increased in the ESI group (0.19% vs. 0.09%, P [ 0.042). When temporally stratified, patients receiving an ESI within 30 days had significantly higher odds of CSF leak (odds ratio: 4.24, 95% confidence interval: 1.97-9.14). CONCLUSIONS: Patients who receive an ESI within 30 days of transforaminal lumbar interbody fusion are at an increased risk for CSF leak. While the incidence of CSF leak remains small, it may be advisable to avoid ESIs at least 30 days before surgery for certain patients.