Risk factors of surgical site infections after supratentorial elective surgery: a focus on the efficacy of the wound-drain-tip culture.

BACKGROUND

Surgical site infection (SSI) is one of the most dangerous complications after neurological surgery and is related to additional postoperative hospital days and an increased risk of death. One method for the early detection of SSI, the wound-drain-tip culture (WDC), has been widely used. However, no investigations on the relation between SSIs and wound drains after neurological surgery have been conducted. We performed this study to identify the risk factors for SSIs and to assess the relationship between SSIs and the results of WDC after elective supratentorial craniotomy.

METHODS

A total of 535 patients underwent elective primary supratentorial craniotomy, and the results of their WDC were analyzed. The mean follow-up period was 14.1 ± 12.2 months. In 347 (64.9 %) patients, the wound drain was removed within 2 days after operation.

RESULTS

Until follow-up, 14 (2.62 %) patients suffered from SSIs. Among the 21 patients with positive WDCs, 8 (38.1 %) patients experienced SSIs. The organisms cultured from the SSIs were matched with the WDC results in 7 (87.5 %) patients. In the multivariate analysis, underweight group (OR = 15.41, p = 0.002), maintenance wound drain over 3 days (OR = 4.202, p = 0.043), and positive WDC (OR = 36.67, p < 0.001) were significantly associated with postoperative SSIs. In 6 (85.7 %) of 7 patients with a positive WDC for Serratia marcescens, SSIs ultimately developed.

CONCLUSIONS

The prognostic value of the positive WDC still falls short of our expectations in the field of neurological surgery. And, the positive WDC results should be cautiously interpreted, considering the virulence of the cultured micro-organisms.