The fate of the seminal vesicle remnant after proximal transection or ligation: an animal model.

PURPOSE: Dissection of the seminal vesicles during radical prostatectomy has the potential to damage the pelvic plexus, thus compromising trigonal, bladder neck and cavernous innervation, and contributing to delayed gain of continence and erectile function. The rate of prostate cancer invasion into the seminal vesicles in currently operated patients is low and in most it may be predicted preoperatively. This situation calls for seminal vesicle sparing radical prostatectomy in select patients, leaving a distal remnant of the seminal vesicles in place. We investigated the fate of the seminal vesicle remnant after proximal transection or ligation in an animal model. MATERIALS AND METHODS: The right seminal vesicle in 36 anesthetized male rats was divided by suture ligation or by transection. The left seminal vesicle served as a control. Six rats per group were sacrificed 1, 2 and 4 weeks after division, respectively. Seminal vesicle morphology was evaluated macroscopically and microscopically. RESULTS: All rats tolerated surgery well and gained weight postoperatively. Transected seminal vesicles were similar in weight and morphology to control contralateral glands. One week after seminal vesicle ligation the remnants became significantly heavier and showed balloon dilatation of the hollow spaces, while the lining epithelium became significantly flattened. Two and 4 weeks after ligation half of the animals showed gland shrinkage and half demonstrated persistent dilatation. CONCLUSIONS: Seminal vesicle transection preserves the gland remnant in a relatively normal morphology, while ligation leads to severe and inconsistent morphological changes. When considering seminal vesicle sparing radical prostatectomy, seminal vesicle transection may be preferred to ligation.