Adhesive Strips vs. Sutures in Lumbar Spinal Fusion: A Non-inferiority Analysis of Surgical Site Infections

Introduction Surgical site infections (SSIs) continue to pose a significant challenge in spine surgery. Skin closure technique has been shown to impact SSI rates, with sutures traditionally considered the standard. Recently, alternative methods, such as adhesive strips, have gained attention for their potential advantages, including shorter operative times, fewer postoperative visits, and improved cosmetic outcomes. However, their efficacy in managing large surgical wounds, particularly in spine procedures, remains underexplored. This study compares SSI rates between sutures and adhesive strips in posterior one- and two-level lumbar spinal fusion using a non-inferiority design. Methods This single-center retrospective study evaluated SSI rates following lumbar spinal fusion using either sutures or adhesive strips for skin closure. Patients who underwent one- or two-level lumbar fusion via an open posterior approach between 2019 and 2022 were initially identified (n = 1,051). Following the application of predefined exclusion criteria, 997 patient records were eligible for review. Propensity score matching (PSM) was then employed to balance key covariates, such as age, sex, ASA classification, surgical time, use of drainage, and the number of levels fused, resulting in 608 patients evenly allocated into two groups. Data were extracted from a prospectively maintained institutional database, and SSIs were classified using the German Krankenhaus Infektions Surveillance System (KISS). A non-inferiority margin of 3% (absolute risk difference) was applied to compare SSI rates. Statistical analyses included t-tests, Mann-Whitney U tests, chi-square tests, and a Wald test for non-inferiority, with the non-inferiority established if the upper bound of the one-sided 95% confidence interval (CI) remained below the 3% margin. Results Following PSM, infection rates within a 30-day postoperative follow-up were 1.64% in the suture group and 1.97% in the adhesive strip group. A one-sided Wald test, using a 3% non-inferiority margin, yielded an absolute risk difference of 0.33% (SE = 1.1%; z = -2.47; one-sided p = 0.0067), with the upper bound of the 95% CI at 2.11%. Conclusion Adhesive strips demonstrated non-inferiority to sutures in terms of SSI rates following one- or two-level lumbar spinal fusion and may offer the added benefit of reduced operative time. However, further research is warranted to confirm these findings and support the broader implementation of adhesive strips in spinal fusion procedures.