Effectiveness of Embolization for Cerebellar Arteriovenous Malformations

Abstract

Cerebellar arteriovenous malformations (AVMs) are one of the most difficult AVMs to treat due to difficulty of access and the small surgical field involved. We reviewed 24 patients with cerebellar AVMs who underwent embolization from 2001 to 2018. We investigated its safety and effects, particularly before extirpation and stereotactic radiosurgery.

Endovascular treatment was performed in 24 patients (mean age, 42.4 years; range, 7-68 years) across 30 sessions. Clinical presentation included the following: hemorrhage (16 patients), headache (4 patients), cerebellar dysfunction (2 patients), and other non-specific symptoms (2 patients). Endovascular pretreatment strategies were as follows: preoperative (3 patients), preradiosurgery (17 patients), and curative (4 patients). The median Spetzler-Martin grade was III. The mean number of embolized arteries and treatment sessions were 3.8 (range, 1-10) and 1.3 (range, 1-4), respectively. AVM volume was ＜10 mL in 8 patients, 10-24 mL in 12 patients, and ≥25 mL in 3 patients. The nidus was located in the right cerebellar hemisphere (13 patients), left hemisphere (6 patients), and the median part including the vermis and the fourth ventricle (5 patients). Aneurysms were associated in 6 patients, including proximal feeder aneurysms (4 patients), flow-related aneurysms (3 patients), and intranidal aneurysms (2 patients). N-butyl cyanoacrylate (NBCA) was used in all patients, and coils were added to 5 patients with AVMs.

Angiographic results revealed ＞40% devascularization in all patients and complete occlusion of the nidus in 4 patients. All associated aneurysms were successfully occluded. Surgical extirpation was successfully performed in 3 patients. Subsequent stereotactic radiosurgery resulted to disappearance of AVMs in 75% of patients after ＞3 years of follow-up (6/8). We encountered 3 procedure-related complications, including hearing disturbance (2 patients) and temporary oculomotor palsy (1 patient). In our study, embolization of cerebellar AVMs was safe and effective which can improve future treatments. From a technical perspective, ischemic complications of the internal auditory artery should be considered in the embolization of anterior inferior cerebellar artery feeders of AVMs at the cerebellopontine angle. Endovascular treatment of associated aneurysms is necessary to reduce perioperative rupture risk during and after secondary treatment. Embolization may be a useful option in multimodal treatments for cerebellar AVMs.