MECHANISM OF HEALING OF THE HUMAN PROSTATIC URETHRA FOLLOWING THERMAL-INJURY

Objectives. To characterize histopathologically the healing response o f the prostatic urethra after laser thermal coagulation and standard t ransurethral resection of the prostate (TURF). Methods. The study incl uded 31 patients who underwent radical prostatectomy because of malign ancy. Twenty-two (first group) had laser radiation either at the time of surgery (18 patients) or from 1 to 12 weeks prior to prostatectomy (4 patients). Nine patients (second group) had TURP from 6 to 96 weeks prior to prostatectomy. Results, Coagulation necrosis followed by slo ughing was observed during the first 10 weeks after laser radiation. A fter the first 10 weeks, the healing response was otherwise stereotypi cal and comparable for both groups of patients. Re-epithelialization w as prominent and resulted from migration of proliferating epithelial c ells from the remaining acinar and ductal epithelium. Squamous metapla sia was conspicuous and present indefinitely. Development of inflammat ory reaction followed by granulation tissue and well-organized fibrobl astic stroma were sequentially recognized, but less prominent. Complet e re-epithelialization and wound sealing was not observed before the f irst 12 weeks of healing. Conclusions. Our study suggests that laser t hermal coagulation and TURF are partial-thickness injuries. Because of the abundant germinal epithelium in the remaining prostatic glands an d ducts, the healing response of the prostatic urethra is relatively u nimpeded and free of contractures, analogous to second-degree skin bur ns.