Pathogens and risk factors for surgical site deep infection in patients undergoing posterior lumbar interbody fusion

OBJECTIVE To explore the distribution of pathogens and risk factors for surgical site deep infection (SSDI) in patients undergoing posterior lumbar interbody fusion. METHODS The clinical data were collected from the patients who underwent posterior lumbar interbody fusion in Hangzhou Xiaoshan Traditional Chinese Medicine Hospital from Mar 2017 to Mar 2020 and received follow-up for no less than 1 year. The diagnosis of SSDI cases was confirmed based on the SSDI diagnosis criteria, the distribution of pathogens was analyzed, and the univariate analysis and multivariate logistic regression model analysis were performed for the risk factors for SSDI. RESULTS Among 350 patients, 20 had SSDI. Totally 23 strains of pathogens were isolated, 16 (69.56%) of which were gram-positive bacteria, 6 (26.09%) were gram-negative bacteria, and 1 (4.35%) was fungus. Staphylococcus aureus and Staphylococcus epidermidis were the predominant species of gram-positive bacteria; Escherichia coli was dominant among the gram-negative bacteria. Univariate analysis showed that the occurrence of SSDI was associated with the age, body mass index (BMI), diabetes mellitus, alcohol drinking, operation duration, blood loss volume and preoperative serum albumin(P<0.05). Logistic regression analysis indicated that BMI and complication with diabetes mellitus were the risk factors for SSDI in the patients undergoing posterior lumbar interbody fusion(P<0.05). CONCLUSION The gram-positive bacteria are dominant among the pathogens isolated from the posterior lumbar interbody fusion patients with SSDI. The BMI no less than 25 kg/m² and complication with diabetes mellitus are the risk factors for SSDI in the patients undergoing posterior lumbar interbody fusion.