I am not aware of anyone who has been cured by vasectomy. In some cases it has made POIS worse or created POIS when it did not exist, I believe. After having a vasectomy most men produce antisemen antibodies. These break down the semen which build up in the testicles because they are not expelled outside of the body. Vasectomy is generally considered minor surgery but there are some pretty bad things that can happen, perhaps even POIS.