Contralateral transcondylar approach for aneurysms of the posterior inferior cerebellar artery-vertebral artery complex.

We report a patient with an aneurysm of the left vertebral artery (VA)-posterior inferior cerebellar artery (PICA) complex that was treated successfully via a contralateral transcondylar approach. The aneurysm was small, pointed laterally to the right, and was located across the midline just above the level of the foramen magnum. This unusual location required special consideration during diagnostic evaluation and surgical planning. To simulate the operative view, the patient's head was turned 45 degrees. This extreme oblique view offered useful information with respect to the choice of side from which the surgical approach should be made. Removal of the posteromedial part of the occipital condyle allowed us to clip the aneurysmal neck without difficulty although the surgical approach was made on the side contralateral to the parent artery. We conclude that the contralateral approach for VA-PICA aneurysms should be considered when aneurysms cross the midline, and that extradural removal of the basal bony structures, including the occipital condyle, can provide a wide wirking space without excessive retraction on the brain stem.