Clinical Characteristics and Risk Factors of Surgical Site Infection in Patients with Open Abdomen with Fistula Undergoing the Abdominal Wall Reconstruction Utilizing Biological Mesh: A Single-Center Retrospective Study

<b><i>Objective:</i></b> This study aimed to evaluate the clinical characteristics and identify risk factors for surgical site infection (SSI) following abdominal wall reconstruction using biological mesh. <b><i>Methods:</i></b> A retrospective analysis was conducted on patients with open abdomen (OA) with fistula who underwent abdominal wall reconstruction with biological mesh at Jinling Hospital between January 2010 and August 2023. Patients were divided into SSI and non-SSI groups, and their perioperative data were compared to identify potential risk factors. <b><i>Results:</i></b> The SSI rate following abdominal wall reconstruction was 23.71% (23/97) in patients with OA with fistula. Significant differences (p < 0.05) were found between the SSI and non-SSI groups in body mass index (BMI), BMI classification, nutritional risk index (NRI) classification, abdominal wall defect partition, pre-operative day one neutrophil count (NEUT), post-perative day one white blood cells (WBCs) and NEUT, post-operative day three WBCs and NEUT, post-operative day seven procalcitonin (PCT) and NEUT, length of hospitalization, and total hospitalization cost. Multifactorial analysis identified normal BMI (odds ratio [OR]: 0.151, 95% confidence interval [CI]: 0.041-0.551, p = 0.004) and high BMI (OR: 0.072, 95% CI: 0.010-0.546, p = 0.011) as protective factors against SSI and moderate NRI (OR: 4.054, 95% CI: 1.069-15.376, p = 0.004), severe NRI (OR: 18.233, 95% CI: 2.971-111.897, p = 0.002), and abdominal wall defect partition (OR: 4.032, 95% CI: 1.218-13.349, p = 0.022) as independent risk factors for SSI. <b><i>Conclusions:</i></b> Normal BMI and high BMI act as protective factors against SSI, whereas moderate NRI, severe NRI, and abdominal wall defect partition are independent risk factors for SSI. Nutritional management and surgical care should be emphasized to reduce SSI incidence in patients with OA with fistula undergoing abdominal wall reconstruction.