FACTORS AFFECTING SIZE AND CONFIGURATION OF ELECTROVAPORIZATION LESIONS IN THE PROSTATE

Objectives. Transurethral electrovaporization of the prostate is a new , minimally invasive technique being used by urologists for surgical a blation of prostatic tissue. There are insufficient data concerning fa ctors affecting the vaporization and coagulation lesions produced by t his technique. The aim of this study was to determine the role of vari ous parameters for adequate tissue evaporation. Methods. This study co mpared bovine liver and human prostatic lesions made by the Vaportrode instrument with those produced by standard electrocautery loops, roll er balls, and laser fibers. Additionally, two electrosurgical instrume nts with differing technical capabilities were compared for their abil ity to cause vaporization of tissue. Results. Results revealed that th e Vaportrode lesions were maximal with a new electrode when used with a Force 40S electrosurgical generator set at 300 W and a drag speed of 25 to 30 seconds per 10 mm of tissue. The lesions produced by this te chnique had a 74% greater coagulation volume compared to a standard ca utery loop. The evaporation defect was comparable to a laser lesion pr oduced in contact at 60 W. Conclusions. We conclude that electrovapori zation under optimal conditions causes a vaporization lesion comparabl e to that produced by high power density laser prostatectomy. Addition ally, the coagulation volume of a vaportrode lesion is considerably gr eater than that produced by standard electrocautery resection.