Ex vivo and in vivo investigations of the novel 1,470 nm diode laser for potential treatment of benign prostatic enlargement

Perioperative haemorrhage is still the major complication of transurethral resection of the prostate (TURP) for benign enlargement of the prostate. Photoselective vaporisation of the prostate (PVP) with the potassium-titanyl-phosphate (KTP) laser has been shown to achieve instant tissue ablation with excellent haemostatic properties. Our aim was to determine the tissue removal capacity, coagulation and haemostatic property of the novel 1,470 nm diode laser, ex vivo and in vivo. We evaluated two prototype diode laser systems at 1,470 nm in an ex vivo, isolated, blood-perfused, porcine kidney model (n = 5; 10 W-50 W) and in an in vivo investigation of beagle prostate (n = 4; 100 W) to assess vaporisation capacities and coagulation properties at different generator settings. The diode laser evaluation was compared with an 80 W KTP laser in the porcine model. After the laser treatment we performed a histological examination to compare the depth of coagulation and vaporisation. The diode laser system (50 W) showed significantly lower (P > 0.0001) capacities for tissue removal than the 80 W KTP laser (0.96 mm +/- 0.17 mm and 5.93 mm +/- 0.25 mm, respectively, P > 0.0001), while coagulation zones were significantly (P > 0.001) larger in diode laser-treated kidneys (3,39 mm +/- 0.93 mm and 1.27 mm +/- 0.13 mm, respectively). In vivo, the diode laser displayed rapid ablation of prostatic tissue with no intraoperative haemorrhage. Histological examination revealed coagulation zones of 2.30 mm (+/-0.26) at 100 W in the diode laser-treated prostates.