Indocyanine Green (ICG) Videoangiography-Guided Dissection of the Sylvian Fissure on the Transsylvian Approach: Technical Note.

Background: The transsylvian approach is a standard method of approach for anterior circulation aneurysms or paraclinoid tumors. Care must be taken, however, to avoid inadvertent obliteration of sylvian veins to prevent postoperative brain swelling and venous infarction. Sometimes, the superficial sylvian veins have complex connections or are not visible because of the thickness of the arachnoid membrane, especially in the case of subarachnoid hemorrhage (SAH). The present report describes a simple method to dynamically visualize the sylvian vein via indocyanine green (ICG) angiography for the purposes of appropriately wide dissection of the sylvian fissure.

Methods: Before dissection of the sylvian fissure and after opening the dura mater, a bolus of ICG is administered intravenously. ICG videoangiography is used for dynamic venography at 10 seconds after the depiction of branches of the middle cerebral artery.

Results: Clear documentation of the sylvian vein was obtained via ICG videoangiography, even in cases of SAH with ambiguous anatomical topography attributable to clot under the superficial arachnoid membrane. ICG was able to differentiate between the sylvian veins of the frontal and temporal lobes, which allowed wide dissection of the sylvian fissure while preserving the veins.

Conclusions: ICG videoangiography is an easy and useful method for identifying the connections and tributaries of the superficial sylvian veins from a transsylvian approach. This method allows wide opening of the sylvian fissure while preserving the sylvian veins.