[Contralateral suboccipital approach for clipping of an unruptured vertebral artery-posterior inferior cerebellar artery aneurysm].

Numerous approaches have been used to access aneurysms of the vertebral artery(VA)-posterior inferior cerebellar artery(PICA)complex for microsurgical clipping. Here, we report the case of a patient with an unruptured aneurysm of the left VA-PICA complex that was successfully treated using a contralateral suboccipital approach. Computed tomography angiography demonstrated a small saccular aneurysm arising from the lateral aspect of the left V4 segment just distal to the PICA origin. The aneurysm deviated to the right from the midline at the level of the jugular tubercle on angiographic evaluation, so we selected a contralateral suboccipital approach. The aneurysm was completely obliterated by neck clipping. After surgery, slight dysphagia and hoarseness appeared, but dysphagia disappeared within several days and hoarseness disappeared within 5 months. VA-PICA aneurysms can vary in their relationship to cranial nerves, brainstem, and bones of the skull base. Neurosurgeons should consider using a contralateral approach for certain aneurysms arising from a tortuous VA that has crossed the midline.