Technical Considerations for Optimizing Flow in Superficial Temporal Artery to Middle Cerebral Artery Bypass: Case Series

Abstract

Background and objectives: Cerebral bypass can provide flow augmentation for select patients with moyamoya disease (MMD) and steno-occlusive cerebrovascular disease (SOCD). Earlier work has suggested that sacrificing the nondonor branch of the superficial temporal artery (STA) can optimize direct flow, which we assessed in real time.

Methods: This was a single-institution observational study of consecutive patients undergoing direct STA-middle cerebral artery (MCA) bypass with indirect encephalo-duro-myo-synangiosis for MMD and SOCD over 1 year. Excluding patients with significant STA-intracranial collateralization, the intraoperative effect of nondonor STA branch temporary occlusion on direct STA-MCA bypass flow was assessed using a Charbel flow probe. Patient characteristics and perioperative and postoperative data were reviewed.

Results: Eleven patients (5 MMD, 6 SOCD; mean age 53.5 ± 15.3 years) underwent combined revascularization (4 left, 7 right). The mean donor STA branch flow increased from 4.91 ± 2.79 (baseline) to 16.63 ± 11.92 mL/min after anastomosis (95% CI 1.25-17.50; P = .015), and to 20.94 ± 10.63 mL/min after nondonor STA branch test occlusion (95% CI 1.71-6.90; P = .002). The parietal STA branch was used as the donor in 8 cases (72%). In 9 patients, the nondonor STA branch was sacrificed. Perioperatively, 1 patient experienced transient dysarthria/paresthesias (9.1%); there were no strokes or other major complications. The median hospital stay was 5.0 (IQR 4.0, 7.0) days, with 81% of patients discharged home. Over a mean follow-up of 6.2 ± 3.0 months, no patients had significant wound-healing issues, and the median modified Rankin Scale score improved from 2 (IQR 1.0, 2.5) preoperatively to 0 (IQR 0.0, 0.0) (95% CI 0.11-1.69; P < .015). Six-month angiography (available in 9 patients) demonstrated 100% direct bypass patency and a median direct bypass flow grade of 2.0 (IQR 2.0, 3.0).

Conclusion: In patients without STA-intracranial anastomoses, STA-MCA direct bypass flow may be optimized safely by nondonor STA branch sacrifice.

Keywords: Carotid occlusion; Case series; Cerebral bypass; Donor graft; Middle cerebral artery; Moyamoya disease; Steno-occlusive cerebrovascular disease; Superficial temporal artery.