Occipital Artery to Middle Cerebral Artery Bypass Using the Descending Branch of the Lateral Circumflex Femoral Artery as an Interposition Graft for Blood Flow Augmentation in Progressive Moyamoya Disease

Background: The superficial temporal artery to middle cerebral artery (MCA) end-to-side anastomosis is the most commonly used direct extracranial-intracranial bypasses type for Moyamoya disease (MMD). In progressive MMD without suitable scalp arteries, other bypass constructs may need to be considered to augment blood flow. Case Description: We present the exceptional case of a 48-year-old woman with progressive MMD and repeated transient ischemic attacks originating from the right hemisphere despite previous bilateral bypasses. We used the descending branch of the lateral circumflex femoral artery as an interposition graft for an occipital artery to M4 MCA bypass with 2 end-to-side anastomoses to augment blood flow. The ipsilateral occipital artery had already formed bilateral transdural collaterals; the goal was to preserve its supply while using the artery as a donor for an interposition graft. Access to the Sylvian fissure was limited because of the previous superficial temporal artery to MCA bypass with an extensive superficial collateral network necessitating preservation. The posterior aspect of the Sylvian fissure was targeted to revascularize the posterior frontal and parietal region using an interposition graft matching the vessel size of a distal MCA vessel segment. Surgery was technically successful, without complications, and the patient recovered without new neurologic deficits. The bypass graft was patent on postoperative computed tomographic angiography and transcranioplasty ultrasound. Conclusions: This case illustrates the need for creative bypass constructs in progressive MMD patients with multiple prior surgeries. Two surgical goals are paramount: flow augmentation with preservation of the existing collateral network to avoid complications and new deficits.