In-vitro comparison of the tissue vaporisation capabilities of different lasers

Abstract

Abstract Objectives Laser-assisted vaporisation of prostate tissue by means of different lasers is in clinical use. Unfortunately up to now there is no direct comparison of the impact of different lasers, neither on their ablation/vaporisation capabilities nor on their sealing capabilities. This study investigates these effects induced by different laser systems. Methods In this study 2 different diode laser wavelengths (λ=980 nm, λ=1470 nm; c.w. mode), 1 Ho:YAG laser (λ=2100 nm; pulsed) and the KTP laser (λ=532 nm; quasi-c.w. mode) were included. The laser light was transmitted via flexible fibres and was applied in contact and non-contact mode onto the surface of the perfused ex-vivo porcine kidney model. The experimental set was kept under water. Macroscopic tissue effects were measured (ablation volume, coagulation rim) and the degree of sealing was determined by the degree of perfusion fluid loss. Results Dependent on the laser power different degrees of ablation, coagulation as well as carbonisation could be induced. Although the size of the coagulation depth differed the degree of sealing showed no significant differences. While an explosive vaporisation of the tissue could be observed using the KTP and the Ho:YAG lasers, the diode laser showed a superficial burning removal with a pronounced coagulation. Conclusion This study showed that laser-induced tissue removal by means of the different laser systems could be achieved if the power applied to the tissue exceeds a certain threshold. Due to the different tissue effects laser individual application techniques should be developed and learned.