Significance of SII and NLR in predicting surgical site infection after cranioplasty

Objective To explore the independent risk factors of surgical site infection(SII) after cranioplasty.Methods A total of 411 patients who underwent cranioplasty in Department of Neurosurgery, the Affiliated Hospital of Xuzhou Medical University from June 2017 to April 2021 were enrolled. According to the presence of surgical site infection(SSI) after cranioplasty, they were divided into two groups: a case group(n=21) and a control group(n=390).The univariate analysis and multivariate logistic regression model were used to analyze the relationship between SSI and the following preoperative indicators, including system immune inflammation index(SII), white blood cell to lymphocyte ratio(WLR), neutrophil to lymphocyte ratio(NLR), monocyte to lymphocyte ratio(MLR),platelet to lymphocyte ratio(PLR), as well as age, body mass index(BMI), diabetes, preoperative American Society of Anesthesiologists(ASA) scores, time of operation, operation duration, repair materials, drainage tube indwelling duration, postoperative cerebrospinal fluid(CSF) leak, and subcutaneous effusion.Results According to univariate analysis, the case group showed increases in preoperative SII 637.83(460.00-670.53), NLR 2.53(2.29-3.10), MLR 0.23(0.19-0.32) and PLR 156.67(118.57-180.83), compared with the control group(P<0.05). There were statistical differences in diabetes, operation duration, drainage tube indwelling duration, postoperative CSF leakage and subcutaneous effusion between the two group(P<0.05). According to multivariate logistic regression analysis, diabetes, preoperative SII value≥516.720, preoperative NLR value≥2.288, operation duration>2 h, drainage tube indwelling duration>48 h, postoperative CSF leakage and subcutaneous effusion area were the independent risk factors for SSI after cranioplasty(P<0.05).The receiver operating characteristic(ROC) curve showed that the area under the curve of preoperative SII and NLR were 0.753 and 0.765, respectively.Conclusions Patients with higher SII and NLR before cranioplasty are more likely to suffer from post operative SSI, which has certain predictive significance. It can be used with other factors to evaluate the risk of infection and improve the prognosis of patients.