Systematic Review with Illustrative Case Example of Salvage Occipital Artery–Middle Cerebral Artery Bypass for Moyamoya Disease

Background: Moyamoya disease (MMD) is a rare cerebrovascular disorder characterized by progressive arterial stenosis with resulting cerebral ischemia. Extracranial-intracranial (EC-IC) bypass is the most common strategy for flow augmentation, typically performed via superficial temporal artery to middle cerebral artery bypass (STA-MCA). Salvage options are more limited, such as the occipital artery-MCA bypass (OA-MCA), with less well studied outcomes.

Methods: An illustrative case example requiring OA-MCA bypass for salvage treatment of refractory MMD was prospectively identified, with additional details furnished via retrospective review as needed. A systematic review was performed in MEDLINE and Embase from inception through 12/2023 using salient keywords and MESH headings. Initial search yielded 79 candidate citations;19 underwent full-text review, and 4 met the study inclusion criteria of reporting primary data on salvage OA-MCA bypass for MMD.

Results: A 55-year-old woman with rapidly progressive MMD underwent bilateral STA-MCA at an outside facility and right OA-MCA bypass here, but continued to have clinically and radiographically progressive disease. Left OA-MCA was recommended and performed uneventfully, with resolved hypoperfusion based on clinical and radiographic criteria. Four manuscripts reported a total of 17 patients with MMD who underwent salvage OA-MCA after failed STA-MCA or indirect bypass. Initial treatment strategies included single-barrel STA-MCA (n = 5), double barrel STA-MCA (n = 3), a variety of indirect synangiosis techniques (n = 4), and combined direct and indirect bypass (n = 5). Mean age at OA-MCA bypass was 22 years (range, 4–81). All OA-MCA bypasses were reported as radiographically patent as of last follow-up, which occurred at a mean 26 months. No instance of recurrent ischemia after OA-MCA bypass was reported. Nine cases had complete or near-complete resolution of clinical symptoms (53%), while seven cases had improved symptoms (41%) and one patient was unchanged (6%). Cerebral perfusion was radiographically restored in 6 patients (35%), improved from baseline but not fully normalized in 9 (53%), and unreported in 2 (12%). Complications included two wound infections (12%) and one symptomatic treatment failure (6%).

Conclusion: OA-MCA is a safe and robust strategy for flow augmentation in the setting of salvage treatment after failed STA-MCA in MMD. Further study is required to identify predictive factors associated with favorable clinical and radiographic outcomes after salvage OA-MCA for MMD.