Spinal dural arteriovenous fistulas: the use of intraoperative microvascular Doppler monitoring.

Spinal dural arteriovenous fistulas are characterized by an abnormal communication between the dural branch of the radiculomedullary artery and an intradural medullary vein. Although the optimal treatment strategy is still debated, a complete interruption of the flow in the fistulas should be obtained. The authors report four cases operated on with intraoperative microvascular Doppler monitoring assistance. In all cases, microDoppler confirmed the location of the fistula and revealed an arterial spectrum on the redundant dorsal medullary veins. After the clipping of the feeder of the arteriovenous shunt, the intraoperative monitoring documented a complete disappearance of the arterial spectrum and the reappearance of the venous pattern. The ultrasonographic changes suggested the complete interruption of the fistulas. Postoperative angiography showed no residual abnormality in all patients. Doppler monitoring during surgery confirms satisfactory interruption of the arterial feeder and may prove useful where initial identification of the feeding vessel is difficult.