The role of indocyanine green videoangiography (ICGV) in surgery of parasagittal meningiomas

Abstract

Dear Editor,We read with great interest the paper entitled “Indocyaninegreenvideoangiography(ICGV)-guidedsurgeryofparasagittalmeningiomas occluding the superior sagittal sinus (SSS) ” byD’Avellaetal.[1].Theauthorsnicelydescribeandfocusontheopportunities that intraoperative ICG videoangiography offersduring surgery of parasagittal meningiomas. We completelyagree with them on the role of extradural examination, whichhas been recently illustrated by Nurshaum et al. [ 5]. We alsoagree on the key role of bridging veins that drain normalparenchyma, and the delicate balance between the need formaximizing resection and preserving neurological function.The authors rightly say: “This technique adds useful informa-tion to the surgeon’s effort to preserve normal venous vascula-ture.” However, their ICG-guided decision making processwith respect to venous sacrifice is not described in detail. Dotheythinkthatbridgingveinswithflowinversioncanbesafelysacrificed? In our experience, this was not found to be true,since we observed that a relief of mass effect after tumordebulking can re-establish flow in an anterograde directionand possibly contribute to reducing peritumoral edema due tovenous congestion [2]. Thus, the direction of venous flowbefore the removal of the meningioma cannot be consideredthe key point. In addition, the problem of venous sacrificeduring surgical approaches for parasagittal meningiomas isnot exhaustively addressed. We recently contributed in thisfield with two papers that describe the use of ICGvideoangiography to evaluate the presence of a collateral ve-nous drainage through an ad hoc designed temporary clippingtest [3, 4]. This technique was widely discussed in many localand international meetings focused on the issue of parasagittalmeningiomas. The authors should be complimented for theircontribution in this field, but indeed their paper does not seemto address the real and critical issue of when during a neuro-surgical procedure a vein can be sacrificed without clinicalconsequences.