Dolichoectatic Posterior Inferior Cerebellar Artery Aneurysm Treated With Excision and Posterior Inferior Cerebellar Artery Double Reimplantation Bypass: 2-Dimensional Operative Video.

Posterior inferior cerebellar artery (PICA) aneurysms account for 0.3% of all intracranial aneurysms, and they commonly present with a complex fusiform morphology that necessitates unique bypass strategies.1-5 An adolescent boy with a familial predisposition to aneurysmal subarachnoid hemorrhage was identified as harboring a fusiform aneurysm of the right distal PICA, characterized by 2 outflow branches. Our recommended treatment strategy involved a right far lateral craniotomy, followed by P1 PICA reanastomosis and P2 PICA reimplantation. Informed written consent was obtained. On exposure, the aneurysm was trapped, and the inflow and 2 outflow PICA branches were excised. Revascularization was established through a P1 PICA end-to-end reanastomosis using running continuous suturing techniques, followed by P2 PICA end-to-side reimplantation into a more distal portion of PICA. Subsequent indocyanine green videoangiography confirmed patency of the P2 PICA reimplantation; however, the initial P1 PICA reanastomosis was noted to be thrombosed. After several unsuccessful attempts to dissolve the thrombus, the decision was made to proceed with a P2 PICA side-to-side in situ reimplantation into the V4 segment of the vertebral artery. Indocyanine green videoangiography and postoperative digital subtraction angiography confirmed patency of the PICA double reimplantation bypass. The patient tolerated the procedure well and was discharged home at his neurological baseline. This video showcases the microsurgical treatment of a complex dolichoectatic, distal PICA aneurysm using a double reimplantation technique, in addition to highlighting bypass decision-making processes for managing complex PICA aneurysms.