We investigated the methods for treating arteriovenous malformations (AVMs) based on the clinical data and questionnaires sent to affiliated hospitals over 9 years. In 27 institutes, there were twice as many embolizations in the second half (5 years) than in the first half, and the overall clinical results improved especially in the latter half. Responses to a questionnaire on treatment strategy for 62 patterns of virtual AVMs simulating various types and situations were obtained from 17 institutes.
There were three general strategies showing more than 70% consensus: 1) radiosurgery for small AVMs without bleeding; 2) embolization plus radiosurgery for large AVMs with ischemic events, and for large, eloquent ones and deep-seated ones with minor hemorrhage; 3) surgical removal for small, middle-sized AVMs with large hematoma except for middle-sized eloquent and deep-seated ones. The strategy used for high-grade AVMs with large hematoma was very different among the institutes. Generally, there is less aggressive surgical extirpation for difficult AVMs, and the dependence on radiosurgery with or without embolization seem to have become greater.
The significance of embolization is that it makes the following treatments easier and more effective. Although the indication of radiosurgery is expanding based on its excellent results, embolization still plays a role to reduce the size and hemorrhagic risks and to eliminate factors unfavorable for radiosurgery.
