Development of a predictive grading system for postoperative ischemia following middle cerebral artery aneurysm clipping

The current study presents a single-surgeon experience with microsurgical clipping of middle cerebral artery (MCA) aneurysms and introduces a grading system to predict postoperative ischaemia. A retrospective analysis of 222 patients with 251 MCA aneurysms treated between 2015 and 2024 was conducted. Key factors, including aneurysm size, dome morphology, neck location, calcification, and rupture status, were evaluated to identify predictors of radiological infarction. A scoring model was developed, assigning points for aneurysm neck distance from the internal carotid artery (>20 mm: 1 point; 10–20 mm: 2 points; <10 mm: 3 points), aneurysm size > 7 mm (1 point), calcification (1 point), and rupture status (1 point). The grading system demonstrated a significant risk gradient, with infarction rates of 0 %, 3 %, 11 %, 35 %, and 83 % for grades 1 to 5, respectively (p < 0.0001). Independent predictors of poor outcomes were identified as a short M1 segment (p = 0.002), aneurysm size > 7 mm (p = 0.019), calcification (p < 0.001), and rupture presentation (p = 0.002). Postoperative ischaemia occurred in 7 patients (23 %) with ruptured aneurysms and 18 patients (9 %) with unruptured aneurysms. This grading system provides a practical tool for stratifying risk and guiding treatment decisions. Further multi-centre studies are needed to validate its broader applicability.