Far Lateral Craniotomy for Posterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Bypass and Trapping of Posterior Inferior Cerebellar Artery Aneurysm: 3-Dimensional Operative Video.

Abstract

Posterior inferior cerebellar artery (PICA) aneurysms account for 3% to 4% of all intracranial aneurysms with an unusually high predilection towards a nonsaccular morphology making microsurgical clipping or endovascular reconstruction of the parent artery difficult. The management of these complicated aneurysms may require revascularization procedures for flow preservation with aneurysm trapping. Recently, there is an increasing inclination towards intracranial-intracranial (IC-IC) bypasses over traditional extracranial donors. This video demonstrates a side-to-side PICA-PICA in situ bypass with trapping of an unruptured incidental right p1-PICA aneurysm. Radiological lesion progression and presence of dysplastic morphological characteristics prompted surgical management. The aneurysm was not amenable to clip reconstruction due to the dysplastic PICA segment and lack of a discernable neck. Institutional Review Board approval and patient consent were sought. With patient in three-quarter-prone position, a right far lateral craniotomy was performed. A left-to-right p3-p3 PICA bypass was completed. The aneurysm was clipped along with proximal PICA at its takeoff from vertebral artery. Indocyanine green videoangiography revealed complete occlusion of aneurysm and proximal PICA and a patent anastomosis with distal right PICA flow. Postoperatively, patient recovered with no new neurological deficits. Dolichoectatic posterior circulation aneurysms are not readily amenable to clip reconstruction. PICA-PICA in situ bypass is an elegant alternative to existing extracranial-intracranial revascularization constructs (occipital artery to PICA).1 There is lower neurological morbidity associated with IC-IC bypass vs PICA reimplantation due to the deep surgical corridor and its proximity to lower cranial nerves. Additionally, in this patient endovascular occlusion posed a higher risk of thrombotic complications and postprocedural cerebellar edema with brainstem compression.2.