Use of a microsecond Er:YAG laser in laryngeal surgery reduces collateral thermal injury in comparison to superpulsed CO2 laser.

ABSTRACT

Despite causing significant thermocoagulative insult, use of the carbon dioxide (CO2) laser is considered gold standard in surgery for early stage larynx carcinoma. Limited attention has been paid to the use of the erbiumyttrium-aluminium-garnet (ErYAG) laser in laryngeal surgery as a means to reduce thermal tissue injury. The objective of this study is to compare the extent of thermal injury and precision of vocal fold incisions made using microsecond ErYAG and superpulsed CO2 lasers. In the optics laboratory ex vivo porcine vocal folds were incised using ErYAG and CO2 lasers. Lateral epithelial and subepithelial thermal damage zones and cutting gap widths were histologically determined. Environmental scanning electron microscopy (ESEM) images were examined for signs of carbonization. Temperature rise during ErYAG laser incisions was determined using infrared thermography (IRT). In comparison to the CO2 laser, ErYAG laser incisions showed significantly decreased epithelial (236.44 µm) and subepithelial (72.91 µm) damage zones (p < 0.001). Cutting gaps were significantly narrower for CO2 (878.72 µm) compared to ErYAG (1090.78 µm; p = 0.027) laser. ESEM revealed intact collagen fibres along ErYAG laser cutting edges without obvious carbonization, in comparison to diffuse carbonization and tissue melting seen for CO2 laser incisions. IRT demonstrated absolute temperature rise below 70 °C for ErYAG laser incisions. This study has demonstrated significantly reduced lateral thermal damage zones with wider basal cutting gaps for vocal fold incisions made using ErYAG laser in comparison to those made using CO2 laser.