When men have a vasectomy reversal 15 years or greater after a vasectomy, there is higher chance of having to undergo vaso-epididymostomy. This complex microsurgical reconstruction connects the upper (abdominal) end of the vas deferens to a microscopic epididymal tubule (in the structure between the testicle and the vas deferens where sperm mature and learn how to swim), instead of simply connecting one end of the vas deferens to the other, which is typically the case in vasectomy reversals. The decision regarding which reconstruction to perform is made during surgery based on a number of intraoperative findings. A very high level of specialized microsurgical expertise is required to perform a vasoepididymostomy with success rates that are deemed acceptable.