Intractable Medial Anastomotic Branches from the Lenticulostriate Artery Causing Recurrent Hemorrhages in Moyamoya Disease.

Abstract

Although superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis is a beneficial treatment for hemorrhagic moyamoya disease, indeterminate mechanisms can cause rebleeding even after successful bypass surgery. We describe a case with a prominent collateral from the lenticulostriate artery (LSA) causing multiple recurrent hemorrhages after successful STA-MCA anastomosis. A 49-year-old Japanese woman with moyamoya disease was referred to our institution after suffering intracranial hemorrhage on 2 occasions. Angiography revealed multiple anastomotic vessels branching from a prominent LSA to connect medullary arteries in the periventricular area corresponding to the location of the hemorrhage. She underwent STA-MCA anastomoses and the bypass widely perfused the MCA territory; however, intracranial hemorrhage recurred in the same hemisphere. Angiography revealed sustained dilatation of the medial anastomotic branches from the LSA with de novo pseudoaneurysm, whereas the lateral branches showed shrinkage. Subsequent surgical treatment included direct bypass targeting the medial hemispheric surface in which the medial branches were distributed; marked shrinkage of the branches and disappearance of the aneurysm were obtained without infarct. Lenticulostriate anastomotic branches distributed medially to the anterior cerebral artery territory should be given more attention as an intractable cause of hemorrhage after successful STA-MCA anastomosis. Although challenging, direct bypass targeting the area reached by collateral vessels could be considered an alternative treatment strategy for this pathologic condition.