Optimum anastomosis angle of end-to-side microsurgical anastomosis for preventing future shear-related risk of thrombosis by computational modeling

End-to-side (ETS) microsurgical anastomosis is a powerful technique in microsurgery. It can overcome vessel’s diameter discrepancy and preserve the distal blood flow. Optimal angle of the ETS anastomosis has been debated and studied, and is currently limited to animal models. Computational model using Finite Element Analysis (FEA) was used to simulate the models with 45 (model₄₅), 90 (model₉₀), and 135 (model₁₃₅) ETS anastomosis angles. Flow dynamics including flow velocity and wall shear rate were studied and compared. Maximum flow velocity ranged from the highest to the lowest in model₁₃₅, model₉₀, and model₄₅, respectively. The velocity in model¹³⁵ showed fluctuation flow. The maximum wall shear rate and distribution were highest in model₄₅ and lowest in model₉₀. ETS anastomosis angle of 90 degrees provided the most favourable flow dynamics to prevent shear related thrombosis in comparison to ETS anastomosis at 45 and 135 degrees.