Study Type – Therapy (case series)
Level of Evidence 4
OBJECTIVE
• To assess the residual power delivered at the tip of a high‐power (80 W) potassium‐titanyl‐phosphate (KTP) laser (80 W Green Light PVTM, Laserscope®; American Medical Systems, Minnetonka, MN, USA) at the end of a photoselective vaporization of the prostate (PVP) procedure, as well as the deflection angle of the laser beam.
MATERIALS AND METHODS
• In total, 65 laser fibres were collected at the end of PVP procedures indicated for symptomatic benign prostatic hyperplasia over a period of 17 months. PVP was performed by two senior urologists.
• The power of laser beam at tip exit was measured for each fibre at the end of the procedures using a photodiode whose signal was amplified, and then quantified by a volt multimeter.
• The deflection angle was measured using a graduated sphere.
RESULTS
• Approximately 70% of fibres delivered less than 40 W at the end of the procedure, which is less than the vaporization threshold.
• Some 9% of fibres had lost their diffraction capacity with a significant alteration of laser beam angulation. These values were not operator dependent.
CONCLUSIONS
• The data show that a large proportion of laser fibers deliver a significantly underpowered beam at the end of the procedures.
• This seems to be caused by peroperative destruction of the fibers, which results in a progressive loss of efficacy of PVP during procedures.