Clinical and hemodynamic outcomes of side-to-side anastomosis in superficial temporal artery-middle cerebral artery bypass for adult patients with moyamoya disease: a prospective cohort study.

Objective: Superficial temporal artery-middle cerebral artery (STA-MCA) bypass, characterized by side-to-side (S-S) anastomosis, has been beneficial in reducing the incidence of postoperative complications and recurrent stroke in patients with moyamoya disease (MMD). However, the safety and efficacy of this unconventional S-S procedure remain unclear. This research aimed to investigate the clinical and hemodynamic outcomes associated with the S-S technique. Methods: Clinical and radiographic data were collected from 50 adult patients with MMD (50 hemispheres), including 23 cases treated with S-S anastomosis and 27 cases treated with end-to-side (E-S) STA-MCA bypass. The patients' demographic information, clinical presentation, associated medical conditions, intraoperative hemodynamics, postoperative hemispheric perfusion status, and clinical course were obtained through a review of medical records, intraoperative microvascular Doppler ultrasonography (MDU), and postoperative CT perfusion (CTP) imaging. Results: There was no significant difference between the S-S and E-S groups in baseline characteristics, postoperative complications, bypass patency rate, neovascularization, and modified Rankin Scale (mRS) scores ( Conclusion: The S-S technique demonstrated a different intraoperative self-flow regulation capacity compared to the traditional E-S technique, but it showed no superiority in postoperative hemispheric perfusion and clinical outcomes. The choice of bypass procedure should be individualized.