Surgical and pathologic observations of epididymal tubules during microscopic epididymal sperm aspiration for intracytoplasmic sperm injection

Microscopic epididymal sperm aspiration (MESA) for sperm retrieval and intr acytoplasmic sperm injection (ICSI) is currently our routine treatment for selected male patients with obstructive azoospermia. In order to refine the surgical technique and obtain better quality sperm for our assisted reprod uctive technology program, we observed the epididymal tubules in 40 session s of surgical exploration of the epididymis for sperm aspiration. Epididyma l tubules with long-term obstruction could be divided into three groups on the basis of clinical observations and pathology findings: markedly dilated , mildly dilated, and nondilated. All of the markedly dilated epididymal tu bules (grade III, n = 10) were azoospermic and ICSI could not be done. Epid idymal sperm obtained from the mildly dilated tubules (grade II, n = 9) res ulted in poorer fertilization (49%) and pregnancy (33%) rates than sperm ob tained from nondilated epididymal tubules (grade I, n = 21, fertilization r ate 72%, pregnancy rate 57%). These findings demonstrate that nondilated ep ididymal tubules are best for sperm retrieval and successful ICSI. We belie ve this observation will be a good surgical parameter for urologic surgeons performing MESA.