[Characteristics of various electrodes for transurethral surgery]

The characteristics of four electrodes for transurethral surgery were examined by resection experiments using porcine muscles. The electrodes were a loop type (uroloop, ENDO care), a roller type (STORZ), VAPOR CUT (STORZ) and WEDGE (Microvasive Co). With the stroke rate fixed at 1.2 cm/second and the electrical output changed to 200, 220, 240 W, the electrode was moved manually by 1 stroke for resection. Sections were weighed, histological changes on the cut surface were observed under a microscope and the excised + vaporized layer and desiccated layer were measured. A similar study was also made with the electrical output fixed at 200 W and the stroke rate changed to 0.6, 1.2, 2.4 cm/second. When the output was increased, the excised + vaporized layer and desiccated layer became deep with the roller-type. The excised + vaporized layer became deep and the desiccated layer tended to become deep with the UROLOOP and VAPOR CUT. No change in either layer was found with WEDGE. When the stroke rate was increased, both excised + vaporized layer and desiccated layer became shallow with VAPOR CUT, but only the desiccated layer became shallow with WEDGE. In conclusion, the proper output and stroke rate were considered to be 240 W and not more than 0.6 cm/second with the roller-type, 220-240 W and 0.6 cm/second with VAPOR CUT and 200 W and 1.2 cm/second with WEDGE.