Balloon test occlusion and endosurgical parent artery sacrifice for the evaluation and management of complex intracranial aneurysmal disease

Abstract

The lifetime risk of developing a cerebral aneurysm is about 5%. For some patients, aneurysms can be reasonably managed by conservative measures, including periodic clinical and imaging surveillance. However, the definitive treatment of cerebral aneurysm disease requires securing the aneurysm by surgically excluding it from the cerebrovascular circulation. Most commonly, this can be achieved by either open surgical clipping or embosurgery. Unfortunately, for a minority of patients, these interventions are inadequate because of many aneurysmal factors, such as complex anatomy, giant and wide neck aneurysmal morphology, peripheral small branch origin and skull base location. In situations like these, sacrifice of the parent artery may be preferable, especially when clinical tolerance or image based vascular reserve can be preoperatively demonstrated during temporary occlusion of the vessel. This preoperative procedure, which is known as the Balloon Test Occlusion (BTO), has several variations and technical nuances that can assist the surgeon in predicting which patients may best benefit from parent artery sacrifice (PAS). Together, BTO and PAS are invaluable tools in the management of complicated and atypical cerebral aneurysms. With regard to cerebrovascular aneurysm disease, this review will summarize the development of these procedures, condense the predictability of the numerous BTO variations and provide an overview of the currently available PAS techniques.