Preliminary evaluation of a novel side-fire diode laser emitting light at 940 nm, for the potential treatment of benign prostatic hyperplasia : ex-vivo and in-vivo investigations

OBJECTIVES: To evaluate, ex vivo and in vivo, the tissue-removal capacity and coagulation properties of a diode laser emitting light at 940 nm, as in the search for potential therapeutic strategies for benign prostatic hyperplasia that cause less morbidity than transurethral resection of the prostate (TURP), various types of lasers have been tested. MATERIALS AND METHODS: A diode laser system (prototype; wavelength 940 nm, Dornier MedTech, Wessling, Germany) was evaluated in an isolated, blood-perfused ex-vivo porcine kidney model at 10-60 W (five kidneys). An in-vivo beagle model was used to investigate the effects on six prostate lobes at a generator output power level of 200 W. After the laser treatment tissue were examined histologically to compare the depth of coagulation and vaporization. RESULTS: With increasing generator output power levels there was an increasing vaporization and coagulation ability for the diode laser at 940 nm in the ex-vivo model. At 60 W the mean (sd) vaporization depth was 1.72 (0.47) mm with a coagulation zone of 9.56 (0.26) mm. In vivo, the diode laser caused rapid ablation with no intraoperative haemorrhage. Histologically, the zone of coagulation had a mean (sd) depth of 4.25 (0.15) mm at 200 W. The tissue removal capacity was estimated at 0.874-1.583 g/min in vivo. CONCLUSIONS: Our findings indicate that diode-laser vaporization at 940 nm is feasible and might be effective for acutely relieving bladder outlet obstruction in an in-vivo setting. Due to its mean coagulation zone of 4.25 mm the diode laser seems to have effective haemostatic properties.