Result: The hemorrhagic rates are sharply different with the sizes,the locations,complicated aneurysms or not,the number and the narrow degree of drainning vein and the drainning direction.

• 结果：由于AVM的大小、位置、是否并发动脉瘤、引流静脉的数目、通畅程度、引流去向等因素的不同，出血的发生率存在着明显的差异。