Degree of Vascular Encasement in Sphenoid Wing Meningiomas Predicts Postoperative Ischemic Complications

BACKGROUND: Sphenoid wing meningiomas (SWMs) can encase arteries of the circle of Willis, increasing their susceptibility to intraoperative vascular injury and severe ischemic complications. OBJECTIVE: To demonstrate the effect of circumferential vascular encasement in SWM on postoperative ischemia. METHODS: A retrospective review of 75 patients surgically treated for SWM from 2009 to 2015 was undertaken to determine the degree of circumferential vascular encasement (0°-360°) as assessed by preoperative magnetic resonance imaging (MRI). A novel grading system describing "maximum" and "total" arterial encasement scores was created. Postoperative MRIs were reviewed for total ischemia volume measured on sequential diffusion-weighted images. RESULTS: Of the 75 patients, 89.3% had some degree of vascular involvement with a median maximum encasement score of 3.0 (2.0-3.0) in the internal carotid artery (ICA), M1, M2, and A1 segments; 76% of patients had some degree of ischemia with median infarct volume of 3.75 cm 3 (0.81-9.3 cm 3 ). Univariate analysis determined risk factors associated with larger infarction volume, which were encasement of the supraclinoid ICA ( P 62 cm 3 was found when the ICA, M1, and A1 vessels all had ≥360° involvement ( P = .001). Residual tumor was associated with smaller infarct volumes ( P = .022). As infarction volume increased, so did modified Rankin Score at discharge ( P = .025). CONCLUSION: Subtotal resection should be considered in SWM with significant vascular encasement of proximal arteries to limit postoperative ischemic complications.