[Direct Bypass for Moyamoya Disease]

We performed direct bypass in adult moyamoya disease and combined direct and indirect bypasses in pediatric cases. Our surgical approach was based on techniques learned from Dr. Hiroyasu Kamiyama, which we refined over time. This paper provides an overview of our method, including its technical modifications and rationale. We performed multiple direct bypasses using the superficial temporal artery(STA) in the anterior and middle cerebral artery territories. Bypass of the anterior cerebral artery is routinely performed in pediatric patients to improve cognitive function. Because secondary bypass using the STA is often unfeasible, we primarily used available resources for the initial surgery. Key procedural refinements include an optimized skin incision to reduce flap ischemia and STA dissection and preparation. Bypass suturing techniques emphasize intima-to-intima anastomosis, which is achieved by optimal stitching to enhance patency and reduce the risk of occlusion. Fish-mouth trimming can achieve a wider orifice while minimizing ischemic time because of the precision of the procedure. Surgical advancements improve the safety and efficacy of moyamoya bypass procedures. Understanding and refining these techniques through continuous training is essential to achieve optimal outcomes.