Reimplantation Bypass Using One Limb of a Double-Origin Posterior–Inferior Cerebellar Artery for Treatment of a Ruptured, Fusiform PICA Aneurysm

Background and Importance: PICA aneurysms are uncommon, and aneurysms associated with anatomical PICA variants are even more rare. Although often treated endovascularly, aneurysms associated with anatomical PICA variants may not be suitable for endovascular intervention given the risk of compromise of brainstem perforators and may be more amenable to open techniques. In this case report, we describe the successful treatment of an aneurysm associated with a double origin PICA (DOPICA) by distally reimplanting one of its limbs.

Clinical Presentation: We report the case of a 78-year-old male with a Hunt and Hess grade 3 and Fisher's grade 4 subarachnoid hemorrhage secondary to a ruptured distal right PICA aneurysm associated with a DOPICA. This was treated with PICA-PICA bypass and trapping of the aneurysm. This is the first reported case in the literature of successful bypass of a DOPICA-associated aneurysm. Radiographically, the bypass remained patent with successful obliteration of the aneurysm, and on discharge, the patient was noted to have a GCS 15 and mRS 3.

Conclusion: This case demonstrates a novel reimplantation bypass for a ruptured aneurysm that exploits this rare variant anatomy of a DOPICA.