Revival of extra-intracranial bypass surgery.
Extra-intracranial bypass surgery has regained significant relevance over the past years. The aim of this review is to highlight the current indications and recent developments in this field. One main indication today is stroke prevention by flow augmentation in the setting of chronic cerebral hemodynamic ischemia which is defined as a combination of steno-oclusive cerebrovascular disease, inadequate collateralization, and loss of cerebrovascular reserve capacity. Another indication is flow replacement in the context of therapy of complex aneurysms and skull base tumors. The herein proposed revival of bypass surgery is due to the progress in individualized, tailored therapeutic strategies as well as patient selection. Furthermore, we witness a dramatic improvement in the surgical technique as well as the development of a broad armamentarium of different bypass types, which today allow tailored revascularization strategies for our patients. Finally, the revival of bypass surgery is also explained by significant technical progress. One of the major developments within the last years is the Excimer laser-assisted nonocclusive anastomosis technique which allows performance of an anastomosis without the need for temporary clipping, thus dramatically reducing the risk for perioperative ischemia in bypass surgery. Extra-intracranial bypass surgery has become a central part of a highly specialized, interdisciplinary strategy for the therapy of complex aneurysms and skull base tumors.