Multistage indocyanine green videoangiography for the convexity dural arteriovenous fistula with angiographically occult pial fistula.

Recently, intraoperative indocyanine green (ICG) videoangiography has become a common technique for treating cerebrovascular diseases. We report a case of dural arteriovenous fistula (AVF) treated with direct surgery using intraoperative ICG videoangiography. A 41-year-old man with right hemiplegia caused by a left subcortical hemorrhage was transferred to our hospital. Digital subtraction angiography (DSA) revealed a left convexity parasagittal dural AVF. Surgical resection of the dural AVF was performed using step-by-step ICG videoangiography 4 times in each dissection procedure, which precisely delineated the structure of the dural AVF. After a circular incision of the dura around the fistular point, repeated ICG videoangiography identified the residual fistula between the pial artery from the middle cerebral artery and the draining vein. Complete disappearance of the AVF was confirmed by ICG videoangiography after this pial fistula was removed. Postoperative DSA revealed no residual AVF. Accurate detection of all fistular points and complete resection, including the dura mater and pial vessels, are necessary to avoid rebleeding caused by the residual dural AVF due to incomplete obliteration of the fistular points. Intraoperative ICG videoangiography could provide information on angiographically occult vascular malformation, such as pial fistulas, that cannot be detected by preoperative DSA. Our findings suggest that multistage intraoperative ICG videoangiography can be quite useful for complete resection of a dural AVF with angiographically occult pial fistula.