Superficial temporal artery-middle cerebral artery double bypass for vertebrobasilar insufficiency due to multivessel intracranial stenosis: A report of two cases with a network-based hemodynamic concept.

Vertebrobasilar insufficiency (VBI) caused by multivessel intracranial stenosis is associated with a high risk of recurrent ischemia and poor outcomes, and its optimal treatment remains controversial. We report two cases of VBI associated with complex intracranial arterial stenosis that were successfully treated with superficial temporal artery (STA)-middle cerebral artery (MCA) double bypass. In both patients, severe stenosis or occlusion of the vertebral and internal carotid arteries was accompanied by a collateral flow through the posterior communicating arteries. Applying a network-based hemodynamic concept that regarded the middle cerebral artery, internal carotid artery terminus, posterior communicating artery, and basilar artery as a single circulation, the STA-MCA double bypass was performed to augment perfusion across both the anterior and posterior territories. Postoperative angiography and SPECT demonstrated increased cerebral blood flow in the middle cerebral and upper basilar regions, and both patients achieved complete resolution of VBI symptoms without new infarctions during the long-term follow-up of 8 and 2 years, respectively. These cases suggest that STA-MCA double bypass can restore global hemodynamic balance by redistributing flow from the anterior to the posterior circulation, representing a valuable revascularization option for selected patients with medically refractory VBI due to extensive intracranial atherosclerotic disease.