Impact of aneurysm shape on intraoperative rupture during clipping of ruptured intracranial aneurysms.

OBJECTIVE: Irregular shape is a known risk factor of intracranial aneurysm rupture causing subarachnoid hemorrhage. The objective of this study was to determine the impact of aneurysm shape on intraoperative rupture (IOR) during microsurgical clipping of ruptured aneurysms. METHODS: This is a retrospective, single-center study of consecutive patients that underwent clipping between 2010 and 2017. Based on 3-dimensional reconstructions from preoperative computed tomography scan and digital subtraction angiography, aneurysm shape was classified as regular aneurysm (RA) or irregular aneurysm (IRA). Risk factors for IOR were identified using univariate and multivariate statistical analyses. RESULTS: A total of 138 patients with 32 RAs and 102 IRAs were included in the analysis. IRAs had a larger size than RAs (8.3 +/- 3.5 vs. 4.6 +/- 2.3 mm, respectively; P < 0.001). There were 36 instances of IOR (26.1%). The IOR rate was greater in IRAs than in RAs (31.1% vs. 9.4%, respectively; P = 0.02). In multivariate analysis, IRA shape was the only significant independent risk factor for IOR (odds ratio, 3.9; 95% confidence interval, 1.0-14.6; P = 0.047). Unfavorable outcome (modified Rankin scale score greater than 2) was not significantly associated with aneurysm shape (P = 0.998) and IOR (P = 0.260). CONCLUSIONS: Our results demonstrate that IRA shape is an independent risk factor for IOR. In the analyzed patient cohort, aneurysm shape and IOR had no significant impact on patient prognosis.