Dissecting Fusiform PICA Aneurysm Repair With Trapping and an Unconventional End-to-Side Reanastomosis: 2-Dimensional Operative Video.

Dissecting fusiform posterior inferior cerebellar artery (PICA) aneurysms are rare and challenging.1,2 One common treatment is occlusion of the aneurysm and parent artery via an endovascular approach without revascularization.3 Revascularization of the artery requires an open microsurgical bypass or endovascular placement of a newer-generation flow diverter.4 We present an end-to-side reanastomosis of the PICA for treatment of a dissecting fusiform left PICA aneurysm with anatomy deemed unfavorable for endovascular treatment in a 62-yr-old man with subarachnoid hemorrhage. After discussions regarding risks, benefits, and alternatives to the procedure, the family consented to surgical treatment.  A far-lateral craniotomy was performed, with partial condylectomy to widen the exposure. The cisterna magna was opened, and the dentate ligament was cut to visualize the vertebral artery. The PICA was identified and traced distally to the aneurysmal segment, which was circumferentially diseased. Perforators were noted immediately distal to the aneurysm. The aneurysm was then trapped, and the afferent artery was transected and brought to the sidewall of the distal artery. The recipient site was trapped with temporary clips, and a linear arteriotomy was made. An end-to-side reanastomosis was performed, temporary clips were removed, and hemostasis was achieved. Postoperative angiography confirmed bypass patency and preservation of the PICA perforators.  Conventional reanastomosis of the parent artery after aneurysm excision is achieved by end-to-end reanastomosis. In contrast, we performed an unconventional end-to-side reanastomosis to revascularize the PICA while leaving the efferent artery in situ to protect its medullary perforators. This bypass is an example of a fourth-generation bypass.5,6 Used with permission from the Barrow Neurological Institute, Phoenix, Arizona.