How I do it: OA-PICA bypass and transcondylar approach for VA fusiform aneurysm

BACKGROUND: Treatment of fusiform vertebral artery aneurysms is demanding because meticulous preservation of perforators and the PICA is required. METHODS: The occipital artery is mapped with Doppler and harvested by incising the overlying muscle, allowing en-bloc elevation of the musculature. Accurate burr-hole placement minimizes venous sinus injury and reduces the bony defect, while early opening of the foramen magnum improves anatomical orientation and facilitates the bypass technique. The extracranial vertebral artery is safely identified with Doppler before performing OA-PICA bypass and subsequent trapping. CONCLUSION: Standardized steps improve technical reliability and enhance clinical outcomes.