Clinical Relevance of Associated Aneurysms with Arteriovenous Malformations of the Posterior Fossa

Abstract

The aim of this study was to determine the frequency of aneurysms associated with arteriovenous malformations (AVMs) of the posterior fossa and their relation to hemorrhagic presentation in comparison to supratentorial AVMs. We performed a retrospective analysis of 474 patients with intracranial AVMs treated in our center from 1990 to 2010. Patients were analyzed for AVM size, drainage type and their clinical course with focus on vessel anomalies including AVM-associated aneurysms. Seventeen (30%) of 57 posterior fossa AVMs versus 46 (11%) of 417 supratentorial AVMs were associated with aneurysms. In six (10.5%) versus seven (1.7%) patients, respectively, flow-associated aneurysms were the source of hemorrhage. Infratentorial location of an AVM was a significant risk factor for the incidence (p < 0.001) and rupture (p < 0.001) of AVM-associated aneurysms. Feeding artery aneurysms in particular represented a risk factor for hemorrhage in the overall group of AVM patients, independently of the location (p < 0.001). The majority of patients with a posterior fossa AVM were treated by combined embolization and surgical removal within one procedure (n = 33, 58%). Feeding artery aneurysms were excluded by endovascular coiling or surgical clipping whenever feasible. Overall treatment-associated permanent morbidity in the subgroup of posterior fossa AVMs was 11% (n = 6) and mortality 4% (n = 2). Posterior fossa AVMs display a significantly higher frequency of associated aneurysms of the adjacent vessels that are correlated to the high bleeding rate compared to AVMs of the supratentorial compartment. We therefore recommend aggressive AVM treatment including the exclusion of associated aneurysms as a minimal therapeutic goal whenever possible.

Associated Aneurysms in Infratentorial Arteriovenous Malformations: Role of Aneurysm Size and Comparison with Supratentorial Lesions

“…Schmidt et al [10] reported a higher incidence of multiple AAs in infratentorial compared with supratentorial AVMs (41 vs. 26%), but did not comment on rupture rates, respectively. Thompson et al [17] could not confirm AA multiplicity to represent a potential risk factor for hemorrhage in both supra-and infratentorial AVMs.…”

“…Bleeding from rupture of an AA was only assumed when meeting the previously defined criteria by Schmidt et al [10] and confirmed by angiographic morphological or intraoperative findings ( fig. 1 ).…”

“…Thus, the aim of this study was to analyze the angiographic and clinical characteristics of AAs, associated with infratentorial AVMs and to compare these findings with our previously published data [8] . Since the posterior fossa and the posterior circulation display unique anatomical conditions and since a different clinical behavior for these lesions is reported [7,[9][10][11][12] , a separate view on this entity is justified.…”

Association between posterior fossa arteriovenous malformations and prenidal aneurysm rupture: potential impact on management

“…Associated aneurysms were the source of bleeding in 10.5% of cases of infratentorial AVMs but only 1.7% of cases of supratentorial AVMs. 8 In the series of posterior fossa AVMs reported by da Costa et al,…”

“…[9][10][11] Some authors have previously noticed that prenidal aneurysm ruptures were frequent when AVMs were located in the posterior fossa. 2,8,12 We sought to confirm, in a series of cases involving patients with AVMs who were treated at our institution, that patients with posterior fossa AVMs frequently present with hemorrhage associated with prenidal aneurysm ruptures. We also aimed to review the outcome for patients presenting with such ruptures who were treated by endovascular means.…”