Long-term patency and final structure after superficial temporal artery-middle cerebral artery bypass surgery: a retrospective study

Abstract Objective The investigation of long-term bypass patency and final structure for patients who underwent superficial temporal artery (STA)-middle cerebral artery (MCA) bypass. Methods This study retrospectively evaluated 20 patients who underwent STA-MCA bypass and had two-year follow-up with cerebral angiography. Patients were grouped as either internal carotid artery (ICA) occlusion (11 cases) or MCA occlusion or stenosis (9 cases) and were diagnosed with either arteriosclerotic (14 cases) or nonarteriosclerotic disease (6 cases). The final bypass formation was examined with cerebral angiography at two-year postoperatively. Diameters of the STA, middle meningeal artery (MMA), and deep temporal artery (DTA) were measured at preoperative angiography and at two-year follow-up. Results No significant differences in STA, MMA, and DTA diameters were reported between the ICA versus MCA group. For arteriosclerotic patients, thicker STA diameters were noted on preoperative angiography. For nonarteriosclerotic patients, MMA and DTA dilatation was noted on at two-year follow-up imaging. For arteriosclerotic patients, all direct bypasses were patented at two years. For nonarteriosclerotic patients, remarkable angiogenesis was demonstrated. Conclusions The long-term patency of a direct bypass may be correlated with its etiology either arteriosclerotic or another cause. An indirect bypass route may develop in patients with a nonarteriosclerotic etiology; therefore, it is important to create a foundation for an indirect bypass with MMA and DTA preservation during craniotomy. In two nonarteriosclerotic patients, STA remained the primary bypass foundation; however, the technique resembled novel angiogenesis after encephalo-duro-arterio-synangiosis and not direct STA-MCA bypass. Therefore, the final bypass structure might be affected by disease etiology.