The detour technique: transcirculation stent coiling for complex cerebellar artery aneurysms. Illustrative cases.

backgroundCerebellar artery aneurysms are exceedingly rare, accounting for only 0.1%-0.3% of all intracranial aneurysms. They often present with wide necks and are usually treated with endovascular means through the vertebral arteries. Transcirculation approaches can offer ergonomic advantages when conventional anterograde endovascular approaches are technically challenging, particularly with incorporation of cerebellar artery origin from the aneurysm and less optimal stent placement angles. OBSERVATIONS: The authors present the transcirculation cases of 2 patients, a 41-year-old female with a 5- to 6-mm right superior cerebellar artery (SCA) aneurysm treated via right posterior cerebral artery P1-to-SCA stent-assisted coil embolization, and a 68-year-old female with a 3 × 3-mm right anterior inferior cerebellar artery (AICA) aneurysm treated using a basilar-to-AICA stent coiling approach. Complete aneurysm occlusion was achieved in both cases without procedural complications. Postprocedural imaging confirmed excellent technical results with preserved parent vessel patency. LESSONS: The transcirculation technique offers a reliable alternative for posterior circulation aneurysms when conventional anterograde access is suboptimal. This study demonstrates its application in cerebellar artery aneurysms, where it provides more favorable stent working angles and supports durable occlusion. This technique is particularly advantageous when the parent cerebellar artery originates from the aneurysm sac, as it facilitates optimal stent placement and enables superior device delivery compared to conventional approaches. https://thejns.org/doi/10.3171/CASE25958.