When should we measure surgical site infection in patients undergoing a craniotomy? A consideration of the current...

Introduction: Surgical site infection (SSI) is a common postoperative complication that causes significant morbidity, particularly in patients undergoing cranial neurosurgery. The treatment of SSI can attract a significant cost by way of increasing length of stay, readmission and reoperation in some cases. Cranial neurosurgical cases without implant surgery are recommended by the centre for disease control to be surveyed for SSI for a 30-day period. The number and proportion of SSI cases that present outside of this 30-day period is unknown.Method: All cranial, neurosurgical procedures at Salford Royal Foundation NHS Trust (SRFT) between October 2011 and April 2015 (n = 3513) were identified and followed up prospectively. The number of SSIs detected, the length of time following operation, microbiological organisms cultured and the need for further neurosurgical procedure was recorded. Mean length of time from operation to detection of SSI was calculated and a hazard function analysis was undertaken.Results: Of the 3531 cases (m = 1903, f = 1628) that underwent cranial neurosurgery included in this series 86 cases of SSI were noted. The mean number of days at which SSI was first clinically diagnosed in this series was 53 days. The time period in which 75% of cases were identified to be SSI was 49 days from the date of the surgical procedure, with 32 cases (37%) presenting outside of the 30-day period of surveillance. Over half of cases required some degree of operative intervention to treat SSI.Conclusion: A longer period of surveillance in cranial neurosurgical procedures is likely to detect a truer rate of SSI in addition to the identification of a notable number of cases that require surgical intervention. We recommend a period of at at least 50 days.