Moyamoya disease and moyamoya syndrome in Ireland: patient demographics, mode of presentation and outcomes of EC-IC bypass surgery.

Background: There are no previously published reports regarding the epidemiology and characteristics of moyamoya disease or syndrome in Ireland.

Aims: To examine patient demographics, mode of presentation and the outcomes of extracranial-intracranial bypass surgery in the treatment of moyamoya disease and syndrome in Ireland.

Methods: All patients with moyamoya disease and syndrome referred to the National Neurosurgical Centre during January 2012-January 2019 were identified through a prospective database. Demographics, clinical presentation, radiological findings, surgical procedures, postoperative complications and any strokes during follow-up were recorded.

Results: Twenty-one patients were identified. Sixteen underwent surgery. Median age at diagnosis was 19 years. Fifteen were female. Mode of presentation was ischaemic stroke in nine, haemodynamic TIAs in eight, haemorrhage in three and incidental in one. Sixteen patients had Moyamoya disease, whereas five patients had moyamoya syndrome. Surgery was performed on 19 hemispheres in 16 patients. The surgical procedures consisted of ten direct (STA-MCA) bypasses, five indirect bypasses and four multiple burr holes. Postoperative complications included ischaemic stroke in one patient and subdural haematoma in one patient. The median follow-up period in the surgical group was 52 months; there was one new stroke during this period. Two patients required further revascularisation following recurrent TIAs. One patient died during follow-up secondary to tumour progression associated with neurofibromatosis type 1.

Conclusions: Moyamoya is rare but occurs in Caucasians in Ireland. It most commonly presents with ischaemic symptoms. Surgical intervention in the form of direct and indirect bypass is an effective treatment in the majority of cases.