TRANSURETHRAL ND-YAG LASER PROSTATECTOMY WITH A LATERALLY FIRING FIBER - LOCAL-EFFECTS ON TISSUE ASSOCIATED WITH ERECTILE DYSFUNCTION

Background and Objectives: Transurethral laser prostatectomy is antici pated to become a recognized alternative to conventional transurethral resection of the prostate. However, the effects of this procedure on the nerves of the pelvic plexus and erectile dysfunction remain unaddr essed. The objective of this study was to evaluate the effects of lase r energy on extent of prostatic damage as well as injury to periprosta tic cavernosal nerves and erectile dysfunction in a canine model. Stud y Design/Materials and Methods: Six adult male mongrel dogs underwent transurethral laser prostatectomy at 30 (n = 3) and 40 (n = 3) watt po wer settings. Total laser energy delivered varied between 6,000 and 13 ,800 joules. Erectile function was evaluated by pelvic nerve stimulati on at 2, 4, and 8 weeks. Animals were then sacrificed to assess histop athology of the prostate at each time point. Results: Histopathologic changes were noted in the prostate in a dose-dependent manner and did not vary with different laser power settings. In dogs that received si milar to 10,000 J, substantial prostate ablation confined within the c apsule was achieved in every prostate gland. Adequate erectile respons es were noted in five of six animals; all received <10,000 J. In one a nimal that received a total dose of 13,800 J, an erectile response was not obtained, and histology revealed both prostatic capsule perforati on in close proximity to the cavernous nerves and thermal neural damag e. Conclusions: We conclude that cavernous nerve damage may result fro m excessive doses of laser energy during transurethral laser treatment of the prostate gland. In canines, the upper limit for periprostatic injury is between 10 and 14,000 joules. (C) 1995 Wiley-Liss, Inc.