[Spinal dural AVM--report of three cases].

A new type of spinal AVM is reported. The characteristics are as follows: All the patients are male over 50-years-old. Their symptoms are insiduous and progressive ischemic pattern. All the lesions locate at the thoracic and lumbar levels. Selective intercostal angiography shows a fistulous AVM adjacent to the intervertebral foramen fed by spinal dural branch and drain into tortuous veins on the spinal cord via radiculomedullary vein. No typical hair-pin configuration by radiculomedullary and spinal cord arteries contributes to the AVM. This type of spinal AVM must be distinguished from so-called singled coiled type spinal cord AVM since pathophysiological features presumably are different from each other; the former is "dural" on anatomical basis, whereas the latter is "pial". Embolization should be recommended as a first choice of treatment to spinal dural AVM.