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Predictive Relevance of the Supplementary Grading Scale In Cerebral Arteriovenous Malformation Surgery
1108 13:10-13:20
Cerebrovascular/304B
Background: The Supplementary grading scale serves as an important tool in evaluating the complexity and outcomes of cerebral arteriovenous malformations (AVMs) surgery. However, its exact predictive efficacy in this context remains to be fully clarified. Methods: In this retrospective monocentric study utilizing a prospectively maintained database, we assessed the predictive significance of the Supplementary grading scale in a consecutive series of 72 patients who underwent brain AVM surgery between 2015 and 2024. We analysed patient demographics, AVM characteristics, supplementary grading scores, surgical approaches, and postoperative outcomes. Results: Of the 72 patients included (39 females, with 29 presenting with rupture), the median age was 44.8 years. Spetzler-Martin (SM) grades were distributed as follows: grade 1 (23 patients), grade 2 (28 patients), grade 3 (15 patients), and grade 4 (6 patients). Preoperative embolization was employed in 6 patients (8.3%) with SM grades 3 and 4. Supplementary grading scale scores ranged from 2 to 8. Of the 61 patients with supplementary scores ≤6, 2 (3.3%, 95% CI 0.3-11.9%) experienced poor postoperative outcomes. Among the 11 patients with supplementary scores >6, 2 (18.2%, 95% CI 4.0-48.9%) had poor outcomes, with most occurring in the SM grade 3 group. Complete angiographic AVM obliteration was achieved in 70 patients (97.2%, 95% CI 89.9-99.8%). Surgical approaches varied based on supplementary grading scores, with more complex cases requiring advanced techniques. Postoperative outcomes, including neurological deficits and angiographic obliteration rates, correlated with supplementary grading scores, underscoring its predictive utility in surgical planning and patient counselling. Conclusions: Not all Spetzler-Martin grade 3 AVMs are equal. The Lawton-Young supplementary grading scale is a valuable prognostic tool in AVM surgery, assisting in preoperative risk assessment and surgical decision-making. Careful patient selection, considering individual technical limitations, suggests the consideration of resection for patients with a supplementary grading scale of 6 or less.

A Proposed Risk Scoring Model for Postoperative Radiological Infarction Following Microsurgery For Middle Cerebral Artery Clip Occlusion
1108 15:40-15:50
Cerebrovascular/304B
Background: Microsurgical clipping of middle cerebral artery (MCA) aneurysms is a critical foundational skill for early-career cerebrovascular neurosurgeons. The complexity and procedural risks associated with these surgeries vary significantly, influenced by specific aneurysm and MCA bifurcation characteristics. This study aims to identify factors influencing the risk of postoperative radiological infarction following MCA aneurysm surgeries and to develop a predictive scoring system. Methods: This retrospective analysis utilized a prospectively maintained database of adult patients who underwent craniotomy and clipping of MCA aneurysms between July 2015 and February 2024, performed by the senior author. Variables such as demographics, comorbidities, rupture status, craniotomy types, technical considerations, and aneurysm characteristics were analysed to identify risk factors for postoperative radiological infarction and poor outcomes (modified Rankin Scale score >2 at 90 days). Key predictors of radiological infarction included the distance of aneurysm neck origin to the ICA bifurcation (>20mm: 1 point, 10-20mm: 2 points, <10mm: 3 points), aneurysm size >7mm (1 point), rupture status (1 point), and presence of calcium on CT (1 point). These factors were used to develop a scoring system. Results: Among 511 initial patients with 596 aneurysms, 222 patients with 251 aneurysms were analysed after exclusions. Thirty patients (13.5%) presented with rupture, and 192 (86.5%) were treated electively. Postoperative radiological infarctions occurred in 23.3% of ruptured cases and 9.4% of unruptured cases. Poor neurological outcomes at 90 days were noted in 20% of ruptured patients and 2.1% of unruptured patients, with no mortality in the elective treatment group. Multiple logistic regression revealed the risk of postoperative radiological infarction for grades 1 to 5 as 0%, 3.1%, 11.3%, 34.5%, and 83.3%, respectively. Conclusion: MCA aneurysms are heterogeneous, with origins varying independently of MCA bifurcation anatomy, M1 angulation, and involvement of lenticulostriate perforators. Multivariate logistic regression identified shorter M1 segments, ruptured status, dome size >7mm, and the presence of calcium on the aneurysm neck as factors associated with poor postoperative radiological outcomes. The proposed scoring system provides a refined method for risk assessment, potentially aiding early career neurosurgeons in optimizing risk stratification. Further validation of this system is necessary.