Risk factors for surgical-site infections in oral cancer patients with microvascular free flap reconstruction–A retrospective study in a single medical center in Taiwan

Surgical site infections (SSI) represent a common complication in head and neck cancer surgery, often leading to prolonged hospitalization, increased healthcare costs, and compromised oncological outcomes. This study aimed to identify risk factors associated with SSI in patients undergoing head and neck cancer surgery with free flap reconstruction at a single medical center in Taiwan. This retrospective study included 216 patients who underwent free flap reconstruction between August 2017 and December 2023. Cases of incomplete data, preoperative infections, death within 30 days post-surgery, and non-malignancy were excluded. Categorical variables were compared using the chi-square or Fisher's exact test, and continuous variables using the t-test or Mann–Whitney U test, as appropriate. Multivariate logistic regression was used to identify independent risk factors. Statistical analysis was performed using JMP Pro version 16.0. The overall SSI rate was 43 % (93/216). On multivariate analysis, longer operative duration increased the risk of SSI (odds ratio [OR]1.004 per minute; 95 % confidence interval [CI] 1.000–1.008). Patients with SSI had significantly prolonged length of stay (LOS) (OR 1.065; 95 % CI 1.002–1.131). Notably, smoking cessation was associated with a higher SSI risk compared to patients who continued smoking (OR 2.709; 95 % CI 1.349–5.439). Regarding clinical T staging, T4a tumors demonstrated lower infection rates (OR 0.142; 95 % CI 1.213–91.212) compared to T4b cases, with T1 and T2 stages showing similar trends ( P = 0.0518, P = 0601). For tumor location, a higher infection rate was noted on buccal mucosa (OR 4.998; 95 % CI 1.129–22.127) and lower gingiva (OR 5.276; 95 % CI 1.202–23.161) compared to upper gingival tumors. Former smoking, prolonged operation time, advanced tumor stage, and location of tumor are significant predictors of SSI in oral and maxillofacial free flap reconstruction. Special attention must be paid to infection prevention when dealing with this patient population.