Photoangiolysis with the 445-nm Blue Laser and the Potassium-Titanyl-Phosphate Laser: A Comparison.

Abstract

Photoangiolytic lasers have yielded significant innovation in laryngeal surgery in the last 25 years. After the discontinuation of the potassium titanyl phosphate (KTP) laser, a novel 445-nm blue laser was developed. The optimal balance between a laser's desired tissue effects and collateral tissue damage is a major determinant of laser selection in microlaryngeal surgery. The shell-less incubation system for the chick chorioallantoic membrane (CAM) simulates the microvasculature of the human vocal fold and is useful for testing effects of laser settings and in simulated surgery. The aim of this study is to compare the tissue effects of the KTP and blue lasers using the shell-less CAM model. The shell-less incubation system contains: polymethylpentene film (used as a culture vessel), calcium lactate and distilled water supplementations. By using this system, the chick chorioallantoic membrane (CAM) can be fully exposed with a good field for surgery simulation. The effects of the 2 lasers (532 nm KTP and 445 nm blue) were quantified at clinically relevant energy settings and laser distances from target. Measures included imaging real-time vascular reactions in the CAM model, post-procedure histologic analysis of CAM tissue and temperature changes. Vessel coagulation and rupture rates were less common with the blue laser compared with the KTP laser. Histologic analysis demonstrated less tissue disruption with the blue laser. Temperature changes were less with the blue laser. In this CAM model with specific conditions, the blue laser reveals less tissue damage than the KTP laser. Suitable working distance and power setting of the laser are necessary for desired tissue effects.Level of Evidence: Level 3.