Thanks for your query.Based on the fact that you have stated it seems that you have Bilateral undescended Testis
your both the testis being in abdomen.You have undergone surgery and one of the Testis was placed in scrotal sac and the other one is still in abdomen.Since your both the testicles were in abdomen for almost 20 years in abdomen it is possible that there may not be Spermatogenesis
which is confirmed on your semen analysis
with no sperms at all.Please get your Testicular Biopsy
done to confirm whether there is spermatogenesis or not.If it turns out to be negative nothing much can be done at this age.You have to consult some Infertility
Specialist for other options to have a child..