Brain retraction injury after elective aneurysm clipping: a retrospective single-center cohort study

Background: BRI is estimated to occur in 10% of skull-base surgery and 5% of aneurysm surgery. These estimates are based on a few studies with unclear methodology. The purpose of this study is to assess the rate of BRI occurrence, its risk factors, and the association between BRI and postoperative focal neurological deficit in patients that underwent elective aneurysm surgery in a single institution. Methods: All patients that underwent elective aneurysm surgery in a single tertiary center in the Netherlands were included. BRI was defined as cortical hypodensities in the surgical trajectory not matching areas of large arterial infarction. Risk ratios were calculated between BRI and (a) the use of temporary parent artery occlusion during clipping, (b) anterior communicating artery (ACom), and (c) middle cerebral artery (MCA) location of the aneurysm, (d) presence of mentioned CVA risk factors, (e) the clipping of > 1 aneurysm during the same procedure, and (f) new focal neurological deficit. Statistical analysis further included t-tests and binary logistical regression analysis on the correlation between age and BRI. Results: BRI was identified postoperatively in 42 of the 94 patients included in this study. A new focal neurological deficit was found in 7 patients in the BRI group. A total of 5 patients had persisting symptoms at 3-month follow-up, of which 2 were caused by BRI. Increasing age is a risk factor for developing BRI. Conclusions: The high rate of BRI and significant risk of new postoperative focal neurological deficit in our patients should be considered when counseling patients for elective aneurysm surgery.