Multimodality Treatment of Posterior Inferior Cerebellar Artery Aneurysms

OBJECTIVE: Posterior inferior cerebellar artery (PICA) aneurysms are heterogeneous, uncommon lesions that can be treated in many fashions. Many previous series have focused on a specific aneurysm subset or treatment paradigm. The aim of this study was to present a comprehensive approach for all PICA aneurysms and analyze outcomes by PICA location. METHODS: All PICA aneurysms treated from 2012 until present were reviewed retrospectively and classified by location. Angiographic and clinical outcome were assessed. RESULTS: We identified 30 patients (average age 56 years, female 76.7%, subarachnoid hemorrhage 83.3%) with 30 aneurysms (saccular 50.0%) who underwent 36 treatments. Locations included the vertebral arterye-PICA junction: 8; anterior medullary (AM): 7; lateral medullary: 3; tonsillomedullary: 1; telovelotonsillar: 5; and cortical: 6. Treatments included clipping: 6; trapping: 2; coiling: 13; balloon-assisted coiling: 1; stent-assisted coiling: 1; flow diversion: 1; and endovascular parent vessel occlusion: 6. There were 3 procedural complications. Recurrence and retreatment rates were 23.3% and 20.0%, respectively. Retreatments included coiling: 1; clipping: 4; and bypass: 1. Seven patients had an associated cerebellar arteriovenous malformation, of whom 5 have undergone resection. Good clinical outcome was achieved in 43.3% at discharge and 84.6% at follow-up (average 10.7 months). Aneurysms distal to the AM segment were more likely to occur in older patients (P = 0.007), with cerebellar arteriovenous malformations (P = 0.031), and to be treated with parent vessel occlusion (P = 0.001). Recurrences were more common for AM segment aneurysms (P = 0.016). Poor outcome was associated with poor SAH grade (P = 0.010), not aneurysm morphology (P = 0.356), location (P = 0.867), or treatment type (P = 0.365). CONCLUSIONS: Our 5-year modern experience highlights the diversity of PICA aneurysms and the need for multimodality paradigms to treat them successfully. The AM segment has the greatest rate of recurrence. Aggressive management is warranted given that the majority of patients can have a good neurologic outcome.