Comparative Analysis of Vaporization and Coagulation Properties of a Hybrid Laser (Combination of a Thulium and Blue Diode Laser) Vs Thulium and Ho:YAG Lasers: Potential Applications in Endoscopic Enucleation of the Prostate

Aim: To test the characteristics of a hybrid laser (combination of a thulium and blue diode laser) vs thulium and Ho:YAG lasers regarding soft tissue ablation. Methods: Tissue samples of fresh nonfrozen porcine kidneys were used to compare the three lasers. A motorized translation XY stage with a fixed fiber holder to control the speed of cutting (2 and 5 mm/s) was used. Five incisions with each laser were performed. Lactate dehydrogenase staining of the embedded specimens was performed to determine incision depth, zones of vaporization, coagulation zone, carbonization grade, and thermomechanical damage of the coagulated tissue. All data are expressed as mean ± standard deviation. Results: The hybrid laser demonstrated the highest vaporization speed (34.4 ± 0.1 mm3/s) and coagulation zones (10 ± 0.1 mm2) at a drag speed of 5 mm/s among the investigated lasers. It showed a two to three times larger coagulation zone compared with the Ho:YAG laser (4 ± 0.1 mm2). The continuous wave thulium fiber laser (cwTFL) showed a significantly higher grade of carbonized tissue compared with the hybrid and Ho:YAG lasers. Conclusions: The hybrid laser showed deeper incisions and a faster vaporization speed compared with the cwTFL and the Ho:YAG laser. It might be an effective tool to combine the advantages of both lasers to effectively vaporize soft tissue with excellent coagulative properties.