[A preliminary study on transurethral electrovaporization of the prostate (TVP) using VaporTrode]

Surgical therapy for Benign Prostatic Hypertrophy (B.P.H.) has mainly depended upon Transurethral Resection of the Prostate (TUR-P) using a cutting loop electrode. Recently, a new technique TVP was reported using the VaporTrode apparatus. We assessed the safety and efficacy of the VaporTrode in a preliminary study.

Histological changes of the muscle and liver of pigs were examined after vaporization using the VaporTrode and a cutting loop electrode. First, histological changes were investigated following vaporization after one stroke at a slow hand speed. Next, histological changes were assessed following vaporization at fixed stroke speed in an experimental model.

At an electrical output of less than 275 W, the depth of the vaporized layer increased as the stroke speed became slower (4.0 cm/s-2.5 cm/s). When the electrical output was 300 W, the depth of vaporized layer increased even at a faster stroke speed (2.5 cm/s-3.0 cm/s.) The depth of the desiccated layer increased as the stroke speed became slower at any electrical output. However, when the stroke speed was 4.0 cm/s, the depth of this layer was less than 2.0 mm. With the cutting loop electrode, the depth of the desiccated layer increased at a higher electrical power, but the change was very small.

To achieve deep enough vaporized and desiccated layers safely, the VaporTrode should be used at a stroke speed slower than 3.0 cm/s and a high electrical power of about 275 W.