Intraoperative neurophysiological monitoring in aneurysm clipping: Does it make a difference? A systematic review and meta-analysis.

The use of intraoperative neurophysiological monitoring (IOM) has been proposed to prevent new neurological deficit during aneurysm clipping. The purpose of this meta-analysis was to evaluate if IOM can prevent neurological injury during clipping of intracranial aneurysm. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews and meta-analysis, we reviewed clinical comparative studies who evaluate the rate of new neurological deficit in patients who had a surgical clipping with and without IOM. Of the 268 citations screened, four studies (including 873 patients) met the inclusion criteria and were included in the meta-analysis. Patients who received surgery with IOM had less new neurological deficit than those who underwent surgery without it (p = 0,04). This finding was more significant in the subgroup analysis of two studies focused on middle cerebral artery (MCA) aneurysm (p = 0,02). However, a specific analysis of the three studies reporting the results of IOM to prevent permanent deficit revealed that there is only a trend for less neurological events in monitored patients without statistically significance (p = 0,05). The use of IOM during clipping of intracranial aneurysm was associated with less new neurological deficit with the obtained evidence of the included studies. However, at long-term follow-up the use of IOM did not correlate with a significant improvement in neurological outcome.