[Bipolar transurethral resection of the prostate versus monopolar transurethral prostatectomy: a pathological study in a canine model].

Objective: To compare the postoperative depths of the coagulation zones and pathological changes between bipolar transurethral resection of the prostate with plasmakinetic energy (PKRP) and monopolar transurethral prostatectomy (TURP) in canines.

Methods: Twenty-five male dogs were randomly divided into a PKRP group (n = 12), a TURP group (n = 12) and a sham-operation control group (n = 1). The dogs were sacrificed, their prostates harvested at 0 week (immediately after surgery), 1 week, 2 weeks and 8 weeks postoperatively and sectioned for pathologic analysis and measurement of the coagulation zones.

Results: At 0, 1 and 2 weeks after the operation, the coagulation depths were (237.73 +/- 20.12) microm, (113.03 +/- 16.65) microm and (106.01 +/- 16.36) microm in the PKRP group, and (200.75 +/-19.34) microm, (129.46 +/- 17.81) microm and (116.04 +/- 25.67) microm in the TURP group (P < 0.01). At 8 weeks, the coagulation zones completely peeled off and the wounds were covered by regenerated urothelial in both of the groups. At 0, 1, 2 and 8 weeks, different inflammatory reactions were observed in the prostates of the PKRP and TURP groups, with some glandular lumens beneath the coagulation zones expanded and epithelia damaged. However, none of these phenomena occurred in the sham-operation control group.

Conclusion: Pathologically, PKRP and TURP inflicted basically similar effects on the prostate of the canine. However, the coagulation zone was deeper intraoperatively and became thinner postoperatively with the former than with the latter, which suggests that PKRP causes less bleeding and less penetrative thermal damage than TURP.