Article
Cerebellar location as a hazardous subgroup of arteriovenous malformations
Die zerebelläre AVM-Lokalisation als besondere Subgruppe
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Published: | May 30, 2008 |
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Objective: Hemorrhage is the primary risk for patients with cerebral arteriovenous malformations (AVM). According to the literature, vertebrobasilar feeding arteries and flow-related aneurysms seem to be particular risk factors for a much higher bleeding rate of posterior fossa AVMs.
Methods: 46 patients with cerebellar AVMs have been identified in our single institution databank and were analyzed for their clinical course, AVM size, associated feeding aneurysms, drainage type and vessel anomalies. Data was determined to assess the bleeding risk compared to the overall group of AVMs.
Results: Hemorrhage was the presenting symptom in 32 of 46 (69%) patients. Clinical data regarding sex, age and gender were unremarkable compared to the supratentorial AVMs. According to the Spetzler-Martin grading, eight patients (17%) belonged to grade IV and V. 32% posterior fossa AVMs were associated with proximal feeding aneurysms. High-flow or fistulous presentations (n=3), intranidal aneurysms (4), venous stenosis (3) and venous aneurysms (2) were found less frequently. Preoperative embolization and surgical removal was performed as one procedure in 71%. Ten patients underwent only operation and in two patients palliative embolization was the only treatment option. Proximal AVM-feeding aneurysms were treated by endovascular coiling in eight patients. Overall treatment associated permanent morbidity in the group of cerebellar AVMs was 5% and mortality 2.6% (n=1).
Conclusions: Posterior fossa AVMs are frequently associated with anomalies of the adjacent vessels and in particular with proximal feeding aneurysms. These features are striking compared to supratentorial AVMs and are obviously correlated to the high bleeding rate. Feeding artery aneurysms are an independent determinant for an increased risk of hemorrhage, especially in cerebellar AVMs. We therefore recommend an aggressive AVM treatment including exclusion of the aneurysm itself to prevent incidences of morbidity associated with the rupture of the aneurysm.