[Risk factors for multiple debridements of the patients with deep incisional surgical site infection after spinal...

To investigate the risk factors that contribute to multiple debridements in patients suffering from deep incisional surgical site infection after spinal surgery and advise medical personnel to pay special attention to these risk factors.

We retrospectively enrolled 84 patients who got deep incisional surgical site infection after spinal surgery from Jan. 2012 to Dec. 2017. The infections occurred within 30 days after the surgery, and the identification met the criteria of deep incisional surgical site infection of Centers of Disease Control (CDC). Early debridement with first stage closure of the wound and a continuous inflow-outflow irrigation system was used, and reasonable antibiotics were chosen according to the bacterial culture results. During the treatment, the vital signs, clinical manifestations, blood test results, drainage fluid colour and bacterial culture results were acquired. If the infection failed to be controlled or relapsed, a second debridement was performed. Of the 84 cases, 60 undergwent single debridement which included 36 male cases and 24 female cases, and the age ranged from 36 to 77 years, with a mean of 57.2 years. Twenty four had multiple debridements (twice in 14 cases, three times in 6 cases, four times in 1 case, five times in 2 cases, six times in 1 cases) which included 17 male cases and 7 female cases, and the age ranged from 21 to 70 years, with a mean of 49.5 years. Risk factors that predispose patients to multiple debridements were identified using univariate analysis. Risk factors with P values less than 0.05 in univariate analysis were included together in a multivariate Logistic regression model using back-forward method.

Multiple debridements were performed in 28.6% of all cases. The hospital stay of multiple debridements group was (82.4±46.3) days compared with (40.4±31.5) days in single debridement group (P=0.018). Instrumentation was removed in 6 cases in multiple debridements group and 4 cases in single debridement group (P=0.049). Flap transplantation was performed in 7 cased in multiple debridements group while none in single debridement group (P < 0.001). Diabetes, primary operation duration longer than 3 hours, primary operation blood loss more than 400 mL, bacteriology examination results, distant site infection were significantly different between the two groups in univariate analysis. In multivariate analysis, primary operation duration longer than 3 hours (OR=3.60, 95%CI: 1.12-11.62), diabetes (OR=3.74, 95%CI: 1.06-13.22), methicillin-resistant Staphylococcus aureus (MRSA) infected (OR=16.87, 95%CI: 2.59-109.73) were the most important risk factors related to multiple debridements in the patients with deep incisional surgical site infection after spinal surgery.

Diabetes, primary operation duration more than 3 hours, MRSA infected are independent risk factors for multiple debridements in patients suffering from deep incisional surgical site infection after spinal surgery. Special caution and prophylaxis interventions are suggested for these factors.