Abstract: PURPOSE: The purpose of this study was to construct a rosette model to predict the risk of surgical site infection (SSI) after surgical treatment of osteoradio-necrosis of the jaw (ORNJ), and to conduct external validation of the model to evaluate its predictive power. METHODS: Five hundred and seven ORNJ surgical cases from March 1993 to October 2014 in Hospital of Stomatology, Sun Yat-sen University were included as model group. In addition, 112 ORNJ surgical cases from January 2000 to November 2021 in Hospital of Stomatology, Southern Medical University were included as validation group. The patients' clinical data were collected. Univariate and multivariate Logistic regression model in SPSS 22.0 software package was used to analyze the contributing factors of patients of ORNJ complicated with SSI. Then a nomogram was established using R programming language to predict the risk of ORNJ being complicated with SSI, internal and external validations were finally carried out. RESULTS: Logistic regression analysis showed that gender, radiation interval (≤2 years), mouth opening(≤1 cm), preoperative infection and procedures were the independent contributing factors of ORNJ complicated with SSI. Harrell concordance index was 0.745 and 0.751 in model group and in validation group, respectively. Calibration curve showed that this model had good discrimination and accuracy. The area under the curve (AUC) of ROC was 0.7446(95%CI: 0.6934-0.7959) and 0.7514(95%CI: 0.6556-0.8473) in model group and in validation group, respectively for predicting the risk of ORNJ complicated with SSI. CONCLUSIONS: Nomogram combining factors like gender, radiation interval, mouth opening, preoperative infection and operation methods can provide us with a comparatively precise way to predict the risk of surgical site infection in patients with ORNJ during perioperative period, which has distinct clinical application value.

Key words: Osteoradionecrosis of the jaws, Surgical site infection, Nomogram