Evaluation of angiographically occult spinal dural arteriovenous fistulae with surgical microscope-integrated intraoperative near-infrared indocyanine green angiography: report of 3 cases.

Background: Spinal dural arteriovenous fistulae (dAVFs), are lesions involving an aberrant connection between a radicular feeding artery and the venous system of the spinal cord at the dural sleeve of the nerve root. When rare dAVFs are occult on digitally subtracted catheter-based angiography, they present a diagnostic and therapeutic challenge.

Objective: We report 3 cases of angiographically occult spinal dAVFs that were evaluated during surgery with indocyanine green (ICG) fluorescent microscope-integrated angiography.

Methods: Three patients with clinical and magnetic resonance imaging features suggestive of a spinal dAVF but no abnormality on digital subtraction angiography underwent surgical exploration with the aid of microscope-integrated ICG videoangiography.

Results: In all 3 cases, ICG identified the intradural vein draining the fistula, clearly distinguishing it from an artery or uninvolved medullary vein.

Conclusions: ICG angiography can rapidly identify a draining vein as it enters the spinal canal even in dAVFs not identifiable on catheter-based digital subtraction angiography.