Analysis Of Risk Factors For Surgical Site Infection After Posterior Internal Fixation Of Thoracolumbar Fractures

Objective:Discussion on the risk factors of operative site infection after posterior fixation thoracic and lumbar fractures in our hospital,to guide clinical work and reduce the rate of infection after operation.Methods:We collected 491 patients admitted to the Department of Orthopedics,Affiliated Hospital of Yan’an University from February 2017to October 2021 with posterior internal fixation of thoracolumbar fractures,including473 infected and 18 non-infected cases,and 157 patients who met the requirements were selected according to the inclusion and exclusion criteria,including 145 non-infected and12 infected patients.The median age and interquartile range（M=48,QR=18）of the non-infected patients and the median age and interquartile range（M=51,QR=19）of the infected patients were used.Patients were split into infected and uninfected groups depending on whether they had developed an infection at the surgical site within a year of the operation.Medical records were collected for the infected and non-infected groups,which included patient factors:age,preoperative albumin,preoperative hemoglobin,preoperative red blood cell count,preoperative white blood cell count,preoperative platelet count,preoperative total lymphocyte count,BMI,preoperative total protein,postoperative albumin,postoperative total protein,postoperative hemoglobin,postoperative red blood cell count,postoperative white blood cell count,postoperative platelet count,postoperative total lymphocyte count,surgical incision length,surgical waiting time,number of internal fixation segments（segments）,gender（male/female）,diabetes mellitus（yes/no）,hypertension（yes/no）,receive table surgery（yes/no）,surgical time（whether≥3 h）,whether allogeneic blood transfusion（yes/no）,intraoperative bleeding volume（≥400 ml）,drainage tube（negative pressure vs.normal）,drainage volume at tube removal（≥50 ml）,duration of drainage tube retention（whether≥3 days）,surgical incision dressing change（whether changed within 24 h postoperatively）.After collecting the above data screening,eligible data were subjected to univariate analysis and further multifactorial logistic regression analysis for positive results.Results:All patients completed the surgery successfully,and all were completely cured of postoperative surgical site infections that occurred.The infection rate was 3.67%.Univariate analysis of the cases included in the study showed statistical differences in intraoperative bleeding（≥400 ml）,preoperative red blood cell count(10¹²/L),postoperative hemoglobin（g/L）,postoperative red blood cell count(10¹²/L),surgical incision length（cm）,and number of internal fixation segments（segments）（P<0.05）.Age,gender,whether combined diabetes mellitus,whether hypertension,whether surgical row table,duration of surgery（≥3h）,whether allogeneic blood transfusion,drainage tube（negative pressure OR normal）,duration of drainage tube retention（≥3d）,drainage flow at extubation（≥50ml）,time of surgery start,whether medication was changed within 24hours after surgery,BMI（kg/m2）,preoperative total protein（g/L）,preoperative hemoglobin（g/L）,preoperative leukocyte count（10⁹/L）,preoperative platelet count（10⁹/L）,preoperative total lymphocyte count（10⁹/L）,postoperative total protein（g/L）,postoperative albumin（g/L）,postoperative leukocyte count（10⁹/L）,postoperative platelet count（10⁹/L）,postoperative total lymphocyte count（10⁹/L）,surgical waiting time（d）were not statistically different（P>0.05）.Multifactorial logistic regression results showed that preoperative low albumin（g/L）（OR=0.851,P=0.028）,intraoperative bleeding（≥400 ml）（OR=7.477,P=0.005）were independent risk factors for postoperative surgical site infection.Conclusion:preoperative low albumin and bleeding during operation（≥400 ml）are more likely to cause surgical site infection in patients with thoracic or lumbar fractures.Active pre-operative preparation and effective peri-operative prevention measures may reduce the incidence of infection at the site of the surgery following posterior internal fixation for thoracic and lumbar fractures.