The Application Value Of SII And PNI In The Early Diagnosis Of Surgical Site Infection After Spinal Internal Fixation

Objective: To investigate the correlation and diagnostic value of SII and PNI on early surgical site infection(SSI)after spinal internal fixation.Methods: A retrospective analysis was performed on 28 cases who had surgical site infection after spinal internal fixation which admitted to the First Affiliated Hospital of Guangxi Medical University from January 2019 to December 2019.According to the principle of randomization,84 patients were selected as the control group from the patients with the same disease who underwent spinal internal fixation surgery on the same time and had no postoperative infection at the surgical site.The routine blood,erythrocyte sedimentation rate(ESR),albumin(ALB),C-reactive protein(CRP)of all patients with preoperative 1 day and 3 days after were detected and analyzed.Correlations of these indexes between the non-SSI group and SSI group were explored.The areas under the curve(AUC)were calculated by the operating characteristic curve(ROC)of the third day after surgery,and the optimal critical value was calculated by using the Youden Index.SPSS19.0 was used for statistical analysis.Results: The PNI,ALB and lymphocytes before operation in SSI patients were significantly reduced compared with that in non-infected patients,while SII was significantly increased(P < 0.01).The PNI and albumin of the infected patients were significantly lower than those of non-infected patients three days after the operation.And CRP and ESR were significantly higher than those of noninfected patients(P < 0.01).According to the postoperative ROC curve,AUC ALB(0.780)>AUC PNI(0.774)> AUC ESR(0.718)> AUC CRP(0.675).The best truncation value,sensitivity and specificity of PNI were 37.45,75.0% and75.0%,respectively.Gram-negative bacteria accounted for 61.29% and Escherichia coli accounted for 29.03% of theses.Gram-positive bacteria accounted for 38.71%,and staphylococcus aureus accounted for 29.03%.Conclusion: The PNI,albumin and lymphocytes decreased before surgery,and the increase of SII were correlated with SSI after spinal internal fixation.PNI can be used as a reference index for the diagnosis of early infection after spinal internal fixation,and as a supplementary reference index for CRP and ESR.The main pathogenic bacteria of SSI after spinal internal fixation in our department were gram-negative bacteria.Escherichia coli and staphylococcus aureus are the most common bacteria.