Usefulness of Intraoperative Monitoring of Perfusion Pressure for Basilar Artery Trunk Aneurysm. A Case Report.

We report a case in which a radial artery bypass graft was used to treat a basilar artery trunk dissecting aneurysm. The patient, a 73-year-old man, was transferred to our hospital because of disturbance of consciousness. A CT scan on admission showed subarachnoid hemorrhage in the prepontine cistern and interpeduncular cistern (Fisher group II). Left vertebral angiography revealed a large irregular-shaped dissecting aneurysm that extended from the anterior inferior cerebellar artery (AICA) to the basilar artery bifurcation. We decided to perform a delayed operation because the neurological grade was very poor (Hunt & Kosnik grade: V). Follow-up left vertebral angiography 4 weeks after admission showed that the aneurysm had become saccular in shape. A radical operation was scheduled because the risk of rebleeding from this aneurysm was considered to be relatively high. The operation was performed via a transpetrosal approach with the use of VA-RA (radial artery)-PCA bypass. First, the aneurysm was trapped, and then it was clipped because pulse-pressure on perfusion pressure of the superior cerebellar artery (SCA) became almost zero. Postoperative angiography revealed another unclipped aneurysm, and a second operation was therefore performed. Angiography after the second operation showed that both aneurysms had disappeared. Finally, we clipped the saccular aneurysms using a VA-RA-PCA bypass. Monitoring of the perfusion pressure of SCA was very useful for deciding whether to perform clipping or trapping of the basilar artery trunk aneurysm.