Keyhole Supraorbital Craniotomy for Aneurysm Clipping in the Setting of Bypass for Moyamoya Disease

BackgroundIn 3%−15% of patients with moyamoya disease, aneurysms occur throughout the circle of Willis. In moyamoya patients treated with a superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass, treatment of a new or an enlarging aneurysm can be complicated by the presence of the bypass and by limitations on the use of standard frontotemporal craniotomies to gain access to the aneurysm. Furthermore, endovascular access can be limited by the presence of fragile moyamoya vessels and precluded by atresia of large vessels.Case DescriptionA 45-year-old female patient with a history of moyamoya disease and previous left STA-MCA bypass presented with an enlarging left superior cerebellar artery aneurysm. We used a keyhole supraorbital craniotomy as a minimally invasive route to treat this aneurysm of the circle of Willis, with minimal interruption to the existing bypass or collateral circulation.ConclusionsIn patients with moyamoya disease who have existing STA-MCA bypass and de novo or expanding aneurysms, treatment is fraught with challenges. We advocate the use of a minimally invasive keyhole supraorbital craniotomy with an eyebrow incision for aneurysms associated with moyamoya disease occurring on the proximal anterior cerebral and middle cerebral arteries, the anterior communicating artery, the basilar apex, the posterior communicating artery, the proximal superior cerebellar artery, and the posterior cerebral artery.