Moyamoya Disease in Infancy: Application of a Novel Indirect Revascularization Technique for Bihemispheric Cortical Synangiosis

INTRODUCTION: Moyamoya disease (MMD) is a rare progressive cerebral arteriopathy characterized by nonatherosclerotic steno-occlusive lesions of the Circle of Willis. Presentation in infancy is rare and usually presents with ischemic stroke. We present a 7-mo old female with bilateral MMD who presented for indirect revascularization after 2 successive strokes in multiple vascular territories. METHODS: We demonstrate a novel indirect revascularization technique in infant MMD whereby the patient's multifocal ischemic burden and STA caliber precluded arterial and myosynangiosis. We instead utilized bihemispheric pericranium for revascularization of bilateral oligemic cerebrum. Through a bicoronal scalp incision and inverted T-shaped pericranial incision, large anteriorly-based pericranial flaps were applied to the exposed pial surface using bilateral hemicraniotomies. Synangiosis extended from the frontal pole into parieto-occipital territories. We additionally performed a literature search on bypass approaches used for infant MMD. RESULTS: A total of 10 infant MMD cases have been reported in the literature. Our case represents the only use of a pericranial graft in an infant without a combined approach. Pial synangiosis, EDAS, and conservative management represent techniques described in this population. Two case series utilized pericranial flaps with EDAS, however, no infants were included nor did revascularization extend beyond traditional margins. Our patient remains stroke and seizure-free for at least 16-months. She is ambulating independently and meeting her pediatric milestones. CONCLUSION: Indirect revascularization is favored in pediatric MMD with approaches primarily utilizing native vessel donor grafts. Bilateral revascularization is performed in a delayed, sequential fashion if indicated. Further, collateralization is limited by the anatomical graft parameters, making hemispheric pathology difficult to comprehensively treat with these approaches. Our case demonstrates the safety and efficacy of utilizing a large bihemispheric pericranial flap on its native pedicle with bilateral hemicraniotomies for revascularization of multiple cerebrovascular territories in severe infant MMD. Our technique also allows for preservation of critical native vessels should the need for reoperation arise.