Identifying Predictors for Aneurysm Remnants After Clipping by Morphometric Analysis and Proposal of a Novel Risk Score

Abstract

Although the risk of aneurysm remnants after microsurgical clipping is generally low, complete aneurysm occlusion is not always guaranteed. We performed a morphometric analysis of intracranial aneurysms to identify predictors for aneurysm remnants and to propose a novel risk score. This is a retrospective, single-center analysis of consecutive patients with ruptured and unruptured aneurysms that underwent microsurgical clipping and postoperative digital subtraction angiography between 2010 and 2018. Based on preoperative rotational angiography, distinct morphological aneurysm characteristics were determined and correlated with postoperative angiographic results. Factors predictive in the univariate and multivariate analyses were determined to establish a risk score for postoperative remnants after aneurysm clipping. Among 140 patients with 166 clipped aneurysms, aneurysm remnants were present in 19.9%. In the multivariate analysis, ruptured aneurysm status (OR: 7.8, 95% CI: 1.7 - 36; p<0.01) and increased aspect ratio (OR: 1.9, 95% CI: 1.0 - 4.0; p=0.07) were associated with postoperative aneurysm remnants. Anterior communicating artery location (p=0.02), internal carotid artery location (p=0.06), increased aneurysm inclination angle (p<0.01) and irregular aneurysm shape (p=0.07) were further predictors for aneurysm remnants in the univariate analysis. These factors were weighted and included into a risk sum score for postoperative aneurysm remnants (range: 0 - 8 points), which performed with good accuracy (AUC = 0.807). After external validation of the proposed risk score, it could help identify cases requiring angiographic control after aneurysm surgery.