Side-to-side superficial temporal artery to middle cerebral artery bypass technique: Application of fourth generation bypass in a case of adult moyamoya disease

BACKGROUND: Moyamoya disease (MMD) is a rare cause of cerebral hemorrhage and ischemia. Spontaneous development of collateral supply from the external carotid artery (ECA) may limit the use of donor arteries used in standard direct bypass techniques. OBJECTIVE: To identify the technical feasibility of side-to-side (S-S) superfcial temporal artery to middle cerebral artery (STA-MCA) bypass and demonstrate the application of fourth generational bypass techniques in the treatment of MMD. METHODS: S-S bypass was performed in order to maintain distal outflow in the donor STA. Fourth generation bypass techniques, including atypical anastomosis construction and intraluminal suturing were utilized. RESULTS: The novel S-S STA-MCA bypasswas performed,with patent flow in bothrecipient MCA and endogenous ECA-ICA collaterals supplied by the distal STA. Technical nuances, including proper alignment of donor vessel, tension reduction, and S-S anastomosis construction with intraluminal suturing technique are essential for successful bypass. Unique flow properties of this bypass were identifed, resulting in flow augmentation to the recipient territory compared to standard end-to-side (E-S) techniques. CONCLUSION: Fourth generational bypass techniques can be successfully applied to MMD, allowing for novel bypass construction. S-S anastomosis can result in potentially benefcial flow properties compared to standard E-S constructions.