A Nested Case-control Study On The Risk Factors Of Surgical Site Infection After Spinal Surgery

Objective: To study the time distribution characteristics and analyze the risk factors of SSI in spinal surgery,including the risk factors of SSI during hospitalization and after discharge,so as to provide a new theoretical basis for spinal surgery medical workers to prevent SSI in clinical work.Methods: The incidence and time distribution of SSI were analyzed in a study cohort of 3,065 patients who undergoing spinal surgery in the affiliated hospital of southwest medical university from October 1,2015,to September 30,2018.Nested case-control studies were used to reveal the influencing factors of SSI,in order to compare whether the risk factors of SSIs in different time periods are different,and explore the causal relationship between different factors and SSIs,calculate the odds ratio.Results: 1.From October 2015 to September 2018,there were 84 cases of SSIs after spinal surgery,and the incidence of SSIs was 2.74%(84/3065),among which 44 cases occurred during hospitalization,the incidence of SSI during hospitalization was 1.44%(44/3065)and 40 cases occurred after discharge,the incidence of SSI during hospitalization was 1.30%(40/3065).2.Conditional Logistic regression univariate analysis of risk factors for SSI in the whole population showed that: diabetes,current smoking,history of spinal surgery,preoperative diagnosis,preoperative length of hospitalization,postoperative length of hospitalization,complications,preoperative anesthesia preparation time,blood transfusion,and ASA grade ?3 associated with surgical site infection of spinal surgery,Variables with statistical significance in univariate analysis were included in the conditional Logistic regression model,and it suggest that diabetes,current smoking,history of spinal surgery,comorbidity,postoperative hospitalization,ASA score ?3 are independent risk factors for the development of spinal surgical site infection.3.Conditional Logistic regression univariate analysis of risk factors for surgical site infection during hospitalization showed that: BMI,current smoking,history of spinal surgery,preoperative diagnosis,length of preoperative hospitalization,blood transfusion,comorbidity,ASA score ?3 were associated with surgical site infection;Variables with statistical significance in univariate analysis were included in the conditional Logistic regression model,and it suggest that BMI,current smoking,complications,history of spinal surgery,blood transfusion are independent risk factors for the development of spinal surgical site infection.4.Conditional Logistic regression univariate analysis of risk factors for surgical site infection after discharge showed that SSI was associated with diabetes,current smoking,complications,preoperative anesthesia preparation time,ASA score ?3;Variables with statistical significance in univariate analysis were included in the conditional Logistic regression model,and it suggest that diabetes,current smoking,complications,ASA score ?3 are independent risk factors for the development of spinal surgical site infection.Conclusion: 1.Some SSIs occur after discharge,if the post-discharge SSI cases are not included in the clinical follow-up,the incidence and risk factors for SSI may be underestimated.2.Risk factors for SSIs were different during hospitalization and after discharge,in clinical work,attention should be paid to the patients after discharge,it can provide theoretical basis for the tertiary prevention,follow-up and continuous nursing of SSI in patients discharged from hospital after spinal surgery.3.Risk factors derived from population-wide nested case-control studies were more helpful for clinicians to formulate reasonable prevention and control measures for SSI.