Effects of indirect bypass surgery for occlusive cerebrovascular diseases in adults.

The efficacy of indirect bypass surgery on hemodynamics in elderly adults with occlusive/stenotic cerebrovascular disease was retrospectively investigated in five elderly patients. Three cases were diagnosed as quasi-moyamoya disease. One patient was diagnosed with moyamoya disease. Of these four patients, three patients showed marked transdural leptomeningeal anastomosis. All patients showed certain areas of hypoperfusion with impairment of the perfusion reserve in the affected areas. All patients underwent encephalo-duro-arterio-synangiosis (EDAS) unilaterally and were followed up for 1-5 years. Three patients showed improvement of hemodynamic status, all of whom showed spontaneously developed leptomeningeal anastomosis in the preoperative angiographies. In two of these three patients, well-developed collateral formation from the graft was observed angiographically. We speculated that in addition to impaired cerebral perfusion reserve, spontaneously developed leptomeningeal anastomosis might be the key factor for the efficacy of indirect bypass in elderly patients with occlusive/stenotic cerebrovascular disease.