Bipolar Versus Monopolar Transurethral Resection of Prostate: Pathologic Study in Canines

ObjectivesTo compare the coagulation depth and pathologic changes of the prostate after bipolar and monopolar transurethral resection of the prostate (TURP) in a canine model.MethodsThe prostates of 25 dogs were treated in vivo with bipolar TURP (bipolar group, n = 12), monopolar TURP (monopolar group, n = 12), or sham operation (sham-operated group, n = 1). The prostate specimens were evaluated pathologically, and the depth of the coagulation zones was measured after the dogs were killed at 0, 7, 14, and 60 days postoperatively.ResultsAt day 0, the coagulation zones of the bipolar group were deeper than those of the monopolar group (P <0.01). At 7 days postoperatively, the coagulation zones had become much thinner in both groups, and the coagulation zones of the monopolar group were thicker than those of the bipolar group (P <0.01). At 14 days, no significant differences were found between the two groups (P >0.05). The pathologic examinations revealed inflammatory reactions in the bipolar and monopolar groups at 0, 7, and 14 days postoperatively. Also, some glandular lumina were expanded and the epithelia destroyed beneath the coagulation zones. At 60 days, the coagulation zones had completely peeled off, and the urothelium had regenerated, covering the surgical wound. None of these pathologic changes were found in the sham-operated group.ConclusionsThe results of our study have shown that the pathologic changes in the prostate after bipolar and monopolar TURP are similar. However, the intraoperative coagulation zones of bipolar TURP are deeper and become thinner early after the operation than those of monopolar TURP.