Risk factors associated with reoperation and recurrent infection following surgical site infections treated with surgical irrigation and debridement

Background Context: Postoperative spinal surgical site infections (SSIs) following multilevel instrumented fusion present significant clinical challenges. This retrospective case-control study examined 176 patients who developed SSIs between 2017 and 2022 at a single institution, focusing on identifying risk factors for reoperation and complications following surgical irrigation and debridement (I&D). Purpose: This study aims to identify risk factors associated with reoperation and complications following SSIs treated with surgical irrigation and debridement after multilevel lumbar instrumented fusion. Study Design/Setting: Retrospective case-control study. Patient Sample: A total of 176 patients who developed SSIs following multilevel instrumented fusion at a single institution between 2017 and 2022 were included. Outcome Measures: The primary outcomes analyzed were recurrence of reoperation and postoperative complications. Methods: The study population included 133 patients (81%) who underwent two-stage I&D and 33 patients (19%) who received single-stage I&D. The overall reoperation rate was 35.2% (62 patients), with recurrent infection occurring in 16.4% (29 patients) at an average of 66 days post-I&D. The total complication rate reached 46.0% (81 patients), with nearly half of reoperations (46.7%) attributed to recurrent infection. Results: Multivariate analysis revealed that estimated blood loss (EBL) exceeding 1000 mL significantly increased the risk of both reoperation (OR=3.652, P =0.002) and recurrent infection (OR=3.246, P =0.021). In addition, an increased number of cervical operative levels correlated with higher reoperation likelihood (OR=1.182, P =0.064). Notably, no significant differences in reoperation rates were found between single-stage and two-stage I&D groups ( P =0.142). Conclusions: The findings suggest that patients undergoing surgical I&D for SSIs following multilevel spinal fusion face substantial risks of reoperation and complications. Excessive intraoperative blood loss emerged as the primary predictor for adverse outcomes, while the choice between single- and two-stage procedures did not significantly impact results. These insights emphasize the importance of effective perioperative blood management strategies and provide valuable guidance for surgical decision-making in managing spinal SSIs. The study indicates that surgical complexity, rather than treatment approach, may be the key determinant of risk.