Introduction: Traditionally, superficial temporal artery-middle cerebral artery (STA-MCA) bypass uses one STA branch. Its augmentation of flow has typically been described as “low flow.” We have adopted a double-barrel technique in which both branches of the STA are utilized. Here we investigate the impact of this method on total flow augmentation as compared to the traditional technique.

Methods: Intraoperative flow probe (Transonic Systems, Ithaca, New York) measurements from cases of STA-MCA bypass were retrospectively tabulated and compared. Prior to anastomosis to the recipient territory, cut flow was measured in the main STA trunk with downstream branches open. After the anastomoses were completed, flow was again measured in the main STA trunk. The higher of these two values was categorized as best flow.

Results: 21 cases of STA-MCA bypass were performed by the senior surgeon with available intraoperative flow probe measurements. 17 of these bypasses utilized double-barrel technique. In four cases, only one STA branch was available. Use of two STA branches provided significantly more flow to the recipient hemisphere (69 versus 39 cc/min, p-value <0.001). 53% (9/17) of double-barrel bypasses provided at least 65 cc/min of flow with a maximum of 120 cc/min. The maximum flow seen with single branch bypass was 40 cc/min. No cases of bypass in this series provided more than 200 cc/min.

Conclusions: Use of double-barrel technique significantly enhances STA-MCA flow augmentation. The method compares favorably to other descriptions of “high-flow” bypass without the morbidity of graft harvest and additional cervical incisions.

Patient Care: Double-barrel STA-MCA bypass may be able to provide higher flow augmentation with the same accessibility as traditional STA-MCA bypass. This provides an additional tool for vascular surgeons treating patients with complex vascular disorders.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of double-barrel STA-MCA bypass technique, 2) Discuss, in small groups, in what cases to consider use of double-barrel technique, 3) Identify an additional method for treatment of complex vascular disorders

References: 1. Duckworth EAM, Rao VY, Patel AJ: Double-Barrel Bypass for Cerebral Ischemia: Technique, Rationale, and Preliminary Experience With 10 Consecutive Cases. Neurosurgery 73:ons30–ons38, 2013 2. Kim JY, Jo KW, Kim YW, Kim SR, Park IS, Baik MW: Changes in Bypass Flow during Temporary Occlusion of Unused Branch of Superficial Temporal Artery. J Korean Neurosurg Soc 48:105–108, 2010 3. Morton RP, Moore AE, Barber J, Tariq F, Hare K, Ghodke B, et al.: Monitoring Flow in Extracranial-Intracranial Bypass Grafts Using Duplex Ultrasonography: A Single-Center Experience in 80 Grafts Over 8 Years. Neurosurgery 74:62–70, 2014 4. Nossek E, Costantino PD, Eisenberg M, Dehdashti AR, Setton A, Chalif DJ, et al.: Internal Maxillary Artery-Middle Cerebral Artery Bypass: Infratemporal Approach for Subcranial-Intracranial (SC-IC) Bypass. Neurosurgery 75:87–95, 2014