Moyamoya disease in children

Abstract

amoya disease (MMD) in children with a focus on the neurosurgical interventions. They provide a detailed description of the superficial temporal artery–middle cerebral artery bypass technique and a list of the indirect bypass techniques, that is, encephalomyosynangiosis, encephaloduroarteriosynangiosis, encephaloduroarteriomyosynangiosis, encephalogaleoperiostealsynangiosis, multiple cranial bur holes, and transfer of omental tissue. The description of the surgical technique is followed by a review of outcome studies of direct, indirect, and combined bypass procedures. From this review, it is clear that the neurosurgical interventions for MMD in the pediatric population are probably beneficial, but the advantages of one particular technique over another remains undetermined. In interpreting data from the reported outcome studies, one must consider that idiopathic MMD may not be the same disease as MMD associated with other disorders such as Down syndrome and so forth. Outcome reports from Asian countries included only idiopathic MMD, whereas those from the Western hemisphere included idiopathic MMD as well as MMD associated with other disorders. This review will serve as a useful reference on MMD in children. RESPONSE: We greatly appreciate Dr. Park’s insightful comments on our review of the surgical interventions for MMD in children. As stated in our review, there are currently no data from the literature supporting direct over indirect revascularization surgery in these children. The age at presentation and angiographic characteristics are probably determining factors that must be taken into account when deciding between direct and indirect techniques. We are currently analyzing the differences in clinical and angiographically demonstrated outcomes between children undergoing direct bypass and those undergoing indirect revascularization. We fully agree with Dr. Park that there are probably significant differences between idiopathic MMD and MMD associated with other syndromes, and this factor must be considered when analyzing the literature. It has been our experience that patients with syndrome-associated MMD can have a greater surgical risk than patients with idiopathic MMD. Although the overall occurrence of syndromic MMD in our population at Stanford is still much rarer than idiopathic MMD, the presence of a syndrome associated with MMD must be considered as a possible confounder.