Incidence of surgical site infection after craniotomy: comparison between three months and twelve months of epidemiological surveillance.

OBJECTIVE: To determine the incidence of surgical site infection (SSI) in patients undergoing craniotomy and to compare 12-month and 3-month post-discharge surveillance periods in terms of their impact on the incidence of SSI in those patients.

METHODS: This was a retrospective cohort study involving 173 adult patients submitted to "clean" craniotomy (without previous contamination of the surgical site), with or without implants, who were followed for six months at a university hospital in the city of São Paulo, Brazil. Patients were screened for SSIs during the first 12 postoperative months.

RESULTS: Of the 173 patients undergoing craniotomy during the study period, 20 developed an SSI during the first 12 months after discharge, the overall incidence of SSI therefore being 11.56%, compared with a 1-month incidence of 8.67% and a 3-month incidence of 10.98%. Among the 106 patients who received implants, the 1-, 3-, and 12-month incidence of SSI was 7.54% (n = 8), 8.49% (n = 9), and 9.43% (n = 10), respectively. Among the 67 patients who did not receive implants, the 1-, 3-, and 12-month incidence of SSI was 10.44% (n = 7), 14.92% (n = 10), and 14.92% (n = 10), respectively.

CONCLUSION: The incidence of SSI after craniotomy is high. Reducing the duration of the post-discharge surveillance period from 12 months to 3 months did not cause significant losses in the numbers of SSIs identified or a substantial decrease in their incidence.