New Perspectives in Surgical Marking Since the Advent of Infrared Laser Angiography.

Abstract

This study investigates the utility of common surgical dyes under direct visualization and infrared laser angiography. Pigments affecting light within the visual (λ = 400-700 nm) and infrared (λ = 700-1000 nm) spectra were placed on subjects spanning the Fitzpatrick scale. Photometric properties of these pigments were assessed under direct visualization and infrared laser angiography. Among patients of various Fitzpatrick classifications, black ink pigment and pigment within the violet spectrum (λ = 380-450 nm) were most distinguishable under direct visualization. Colored inks, gentian violet and methylene blue dyes, were not visualized under infrared laser angiography. Black permanent ink appeared under both direct visualization and infrared laser angiography. Indocyanine green suspended in ethyl alcohol and applied to skin as a marking pen appeared clear under direct visualization and was detectable under infrared laser angiography. Black permanent marking ink allows visualization of surgical markings under infrared laser angiography, whereas gentian violet and methylene blue did not interfere with infrared visualization. Indocyanine green suspended in ethyl alcohol is a contemporary marking pen that may be used to outline anatomical surface landmarks under infrared laser angiography.