Epidemiological Analysis And Risk Factors Investigate Of Surgical Site Infection After Lumbar Internal Fixation

Background and ObjectiveSurgical site infection(SSI)after lumbar internal fixation is the most common hospital-acquired infection in spinal surgery,which greatly increase the risk of failure of lumbar spine surgery,seriously affects the quality of life of patients and aggravates their pain.The purpose of this study is to review the epidemiological characteristics and investigate its risk factors of SSI after lumbar internal fixation in the department of spinal surgery of the third affiliated hospital of Southern Medical University,which is designed to provide some references for reducing the incidence of SSI after lumbar internal fixation.MethodsCollected the data of 1073 cases of posterior lumbar internal fixation performed in the department of spinal surgery of the third affiliated hospital of Southern Medical University from January 1,2016 to December 31,2018,including 516 males and 557 females,aged 18?84 years(54.67±13.23 years).There were 212 cases of hypertension,90 cases of diabetes mellitus,27 cases of obesity(BMI?28kg/m2),179 cases of recent smoking history,386 cases of lumbar disc herniation,350 cases of lumbar spinal stenosis,147 cases of lumbar spondylolisthesis,107 cases of lumbar fracture,54 cases of scoliosis and 29 cases of lumbar tumor.The surgical site infection occurred in 19 cases,including 11 males and 8 females,aged 18~77 years(54.89±16.67 years).There were 7 cases of hypertension,5 cases with diabetes mellitus,3 cases of obesity(BMI>28kg/m2),2 cases of recent smoking history,6 cases with lumbar disc herniation,5 cases with lumbar spinal stenosis,3 cases of lumbar spondylolisthesis,4 cases of lumbar fracture,1 case of scoliosis and 0 cases of lumbar tumor.The postoperative time of infection and the distribution of pathogenic bacteria were collected and the epidemiological characteristics were analyzed.Data such as sex,age,BMI,smoking history,hypertension,diabetes,preoperative steroid use,ASA classification,starting time of operation,time of operation,blood loss,transfusion,internal fixation levels and whether the surgery was revision were collected.Univariate analysis and multivariate Logistic regression analysis were used to investigate the risk factors of infectionResultsA total of 1073 cases were included,and 19 cases had surgical site infection,with an incidence of SSI after lumbar internal fixation of 1.77%,Among them,there were 15 cases of early infection(5 cases of Superficial incision infection and 10 cases of deep incision infection)and 4 cases of delayed infection(all of which were deep incision infection).Among the 19 infected patients,24 strains of pathogenic bacteria were cultured positive,among which gram-positive bacteria(staphylococcus aureus was the most common),followed by coagulase negative staphylococcus(staphylococcus epidermidis was the most common)and gram-negative bacteria.The delayed infection was mainly caused by coagulase negative staphylococcus.Obesity(BMI>28kg/m2)(OR=6.704,P=0.005),diabetes history(OR=4.071,P=0.008),long operation time(operation time?3h)(OR=7.102,P=0.000),the surgery starts at night(after 17:00)(OR=3.981,P=0.018)were independent risk factors of surgical site infection after lumbar internal fixation.ConclusionThe main pathogenic bacteria of surgical site infection after lumbar internal fixation are gram-positive bacteria(the most common is staphylococcus aureus),followed by coagulase negative staphylococcus,a small amount of which is caused by gram-negative bacteria.Coagulase negative staphylococcus and other opportunistic pathogens are the most common in delayed infections.Obesity,diabetes history,long operation time,the surgery starts at night were independent risk factors of surgical site infection after lumbar internal fixation.