TRANSURETHRAL ELECTROVAPORIZATION OF THE PROSTATE (TVP)

Transurethral electrovaporization (TVP) of the prostate has become popular during the past 3-4 years. The procedure consists of the combination of the two electrosurgical effects, vaporization and coagulation, into one motion. This makes prostatic tissue removal with minimal bleeding feasible. The operative technique involved is familiar to all urologists since the equipment used is the same as for classic TURP. In TVP the generator works at a cutting current 25-70% higher than that of standard TURP and roller edge or band loop electrodes are used. Maximum current density and vaporization efficiency of the electrode is obtained at its leading edge for the depth of 3-4 mm where the fresh prostatic tissue has the least resistance; in the 2-3 mm of the underlying prostatic tissue the electrical resistance increases and current density decreases causing dessication and coagulation. A number of studies have been published to evaluate the clinica! efficacy of electrovaporization: they show that 3-12 months alter surgery, AUA symptom score decreases by 65-80% paralleled by a 100% increase of maximum urinary flow rate (Qmax); pressure flow studies show a significant reduction of the detrusor pressure by approximately 50%; the incidence of retrograde ejaculation ranges from 15 to 92%, and that of impotence from O to 15%. These results are comparable to that of classic TURP. The therapeutic failure rate (6%), also, is similar to that of TURP. Contrary to TURP, blood loss and the risk of blood tranfusion are minimal for TVP and fluid absorbtion, with risk of TUR syndrome, is limited; also the catheter can be removed within 48 hours with a shorter hospital stay and lower costs, Thus, TVP represents an evolution of TURP. Nevertheless the best results are obtained in middle size prostates. Its clinica! efficacy is reduced in prostates exceeding 50 ml. The negative aspects of TVP are the greater incidence of irritative voiding symptoms and the fact that it is not possible to obtain material for histologic examination. Prostatic tissue vaporization can be obtained using the laser, too. Nevertheless TVP remains preferable given its lower cost and given the lo.wer catheterization time, the lower incidence of post surgical irritative symptoms and of therapeutic failure involved with its use.