Intraoperative sonographic assessment of graft patency during extracranial-intracranial bypass

Extracranial-intracranial (EC-IC) bypass may be necessary to facilitate tre atment of unclippable posterior circulation fusiform aneurysms. Although in traoperative digital subtraction angiography (DSA) allows assessment of gra ft patency, this technique, because of difficulties inherent in performing selective catheterization and angiography in the operating room, has limita tions. Duplex sonography, in contrast, is easily performed, and provides in formation regarding graft patency and blood flow direction during EC-IC byp ass procedures. This latter information proved useful in determining the ti me of parent artery occlusion after two EC-IC bypass procedures performed f or treatment of a fusiform midbasilar artery aneurysm.