Ruptured bilateral vertebral artery dissecting aneurysms involving the posterior inferior cerebellar arteries: a combined surgical and endovascular strategy. Illustrative case.

backgroundRuptured bilateral vertebral artery dissecting aneurysms (VADAs) are rare and pose significant challenges, particularly in identifying the rupture site. Posterior inferior cerebellar artery (PICA)-involved bilateral VADAs require preservation of perfusion to the PICA territory, further complicating management. OBSERVATIONS: A man in his 50s presented with subarachnoid hemorrhage caused by bilateral VADAs involving both PICA origins. Preoperative imaging suggested a right-sided rupture. However, intraoperative inspection using the bilateral condylar fossa approach revealed that the left side was the rupture site. A PICA-PICA bypass was initially performed, followed by an occipital artery-left PICA bypass to revascularize the bilateral PICA territories. The left vertebral artery was then surgically occluded at the dural penetration point and just distal to the origin of the left PICA, excluding the aneurysm in a blind-ended configuration. The patient recovered without major complications. LESSONS: In ruptured bilateral VADAs involving the PICAs, a strategy combining direct intraoperative identification of the rupture site with revascularization of the bilateral PICA territories using a bilateral condylar fossa approach is effective and facilitates subsequent endovascular treatment while preserving critical circulation. https://thejns.org/doi/10.3171/CASE26347.