Abstract
Among 25 patients with cerebral arteriovenous malformation (AVM), who were followed for more than two years after gamma unit radiosurgery, treatment outcomes were unsatisfactory in eight patients. The patients consisted of two cases whose AVMs were angiographically shown to have not been completely obliterated following the initial treatment and were therefore reirradiated, three who refused further angiographic examination despite only partial obliteration of the nidus having been obtained, and two cases of complete nidus obliteration with radiation-related morbidity or with angiography-related mortality. In the one remaining case, no neurodiagnostic imaging studies have thus far been performed because the patient has refused them. Factors which could have contributed to unsatisfactory treatment outcomes in these eight cases were as follows (three patients had multiple factors): 1) inappropriate patient selection criteria for this procedure (three cases), 2) poor delineation of the AVM on stereotactic angiography (one case), 3) imprecise delivery of the radiation dose due to incorrect dose planning (three cases), and 4) inadequate follow-up after radiosurgery (four cases). Successful radiosurgical treatment requires appropriate patient selection and precise delivery of the radiation dose to the target, as is well known. Furthermore, we emphasize that meticulous long-term follow-up is essential in successfully managing all radiosurgically treated AVM patients.
