Risk Factors For Surgical Acute Site Infection After Posterior Lumbar Interbody Fusion And Treatment

Objective:The purpose of this study was to analyze the factors that may increase the risk of surgical site infection(SSI)following posterior lumbar interbody fusion and find the relationship between them.Combining the previous literatures and the treatment experience,we want to discuss the strategy of treating surgery site infection.Method:1.Research objectThis retrospective case-control study involved 3080 patients who underwent lumbar operation treatment from 2011 to 2016.Inclusion criteria:patients who underwent posterior lumbar interbody fusion primarily were taken into analysis.All the patients had the complete history record,operative data and magnetic resonance imaging(MRI)within 2 months of surgery.Patients who developed SSI within 30 days of the operation constituted the study group.Exclusion criteria:subacute and chronic infection,the patients who underwent operations for fracture,scoliosis,tumor,reoperation and so on.The patients who were treated with minimally invasive surgery were also excluded.2.Data collectionThe basic information,such as age,gender,height,weight,surgery time,drainage,diabetes,BMI,preoperative albumin(Alb)and hemoglobin(HGB)level,number of levels involving in the surgery,blood volume,and UTI etc.were collected from the medical history system.Subcutaneous fat thickness and multifidus muscle fat degree were measured with software in the pictures of MRI.Collecting the therapeutic schedule of infected patients.3.Data analysisData was analyzed using IBM SPSS Statistics 20.0(SPSS,Inc.,Chicago,USA).To compare two groups containing categorical variables,independent sample t test was used.In case of measurement variables,Chi-square test was used.Pearson's correlation coefficient was applied for measuring correlation coefficient between the two categorical variables.Bivariate analysis was performed to identify associations between indexes and presence of SSI.The associations between potential risk factors and SSI were also analyzed using multivariate logistic regression model.Differences were considered significant at 5%(p<0.05)Results:There were totally 3080 lumbar operations from 2011 to 2016.Of the 1426 patients who meet the inclusion criteria,52 patients suffered the SSI.The total infection rate was 3.64%.Male,age>60 years old,subcutaneous fat thickness,lumbar multifidus muscle fat infiltration and duration of drainage were significant risk factors for SSI by multivariate logical regression analysis(p<0.05).Correlation was not found between body mass index(BMI)and fat infiltration of lumbar multifidus muscle(p>0.05).In the 52 infected patients,34 patients were cured with antibiotic merely,16 patients were re-operated with debridement and only 2 patients needed to remove the internal fixation.Conclusion:Male,age>60 years old,subcutaneous fat thickness,fat infiltration of multifidus muscle and duration of drainage were related to surgical site infection in posterior lumbar interbody fusion.Fat infiltration of multifidus muscle was spine-specific SSI risk factors independent of the BMI.In the acute surgery site infection,we suggest that patients should be treated with reoperation and intervention with effective antibiotics as early as possible,however,removing the implant is not necessary.