Intraoperative Identification of the Shunt Point of Spinal Arteriovenous Malformations by a Selective Arterial Injection of Saline to Subtract Signals of Indocyanine Green: Technical Note

It is crucial to identify a shunt point for spinal arteriovenous malformation (AVM) treatment. For this purpose, some intraoperative supports have been reported—intravenous injection of indocyanine green (ICG), selective arterial injection of ICG, and selective arterial injection of saline with a high frame rate digital camera. However, there are difficulties in accurately identifying the shunt point, especially if the lesion has multiple feeders. The aim of this technical note was to report a novel method, selective arterial injection of saline to subtract signals of ICG, to precisely identify perimedullary arteriovenous fistula shunt points having multiple feeding arteries. After exposing the lesion, a 4-F catheter was cannulated into the origins of the segmental artery. ICG was injected intravenously as a first step, and then heparinized saline solution was flushed from the catheter. Compared with other methods, this method could identify the exact shunt point and was effective for certain shunt point obliterations. Despite having similar invasiveness, selective arterial injection of saline to subtract signals of ICG is superior to previously described techniques, such as selective arterial injection of ICG. Therefore, it will be useful in spinal arteriovenous malformation surgical treatment.