Development of a new alloplastic spermatocele demonstrating successful sperm retrieval in an animal model

Objective: To create an alloplastic spermatocele capable of repeated sperm aspiration. The alloplastic spermatocele has long been a theoretical solution to infertility for those patients with congenital absence of the vas deferens or irreversible obstruction of the male reproductive ductal system. Recent studies have suggested that sperm from efferent ducts are capable of fertilization. Clinical use of alloplastic spermatoceles for collection of epididymal sperm has resulted in unacceptably low pregnancy rates. Improvement in spermatocele function may occur if a microsurgical anastomosis is performed to the epididymis. Design: A newly designed alloplastic spermatocele was implanted in 17 mature male rabbits. The faceplate of the device had a 0.7-mm orifice, allowing direct precise microsurgical anastomosis to a specific loop of the epididymal tubule. Results: Sperm retrieval was possible in 16/17 (94%) animals. Repeated successful aspirations (total of 73) were performed in all but one animal. The total number of sperm collected per spermatocele averaged 115 x 10⁶ (range 0 to 734 x 10⁶). The sperm motility varied widely between animals and specimens, with a maximum average of 21.6% motile sperm/aspirate per animal. All spermatoceles eventually occluded (mean time of occlusion 14 days; range 3 to 30 days). The prostheses with the attached epididymides were examined histologically. Conclusions: This prototype alloplastic spermatocele allows repeated high density sperm retrieval over a short period of time. Low sperm motility may be less problematic clinically as new techniques of IVF become available.