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

Neurosurgery 80:957–966, 2017

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 preoperativemagnetic 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 diffusionweighted 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 cm3 (0.81-9.3 cm3). Univariate analysis determined risk factors associated with larger infarction volume, which were encasement of the supraclinoid ICA (P < .001), M1 segment (P < .001), A1 segment (P = .015), and diabetes (P = .019). As the maximum encasement score increased from 1 to 5 in each of the significant arterial segments, so did mean and median infarction volume (P < .001). Risk for devastating ischemic injury >62 cm3 was found when the ICA, M1, and A1 vessels all had ≥360◦ involvement (P = .001). Residual tumorwas 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.