Jenny, I highly doubt that your hubby became sterile from the back surgery-if he is sterile. It would me that the drs. would have to do a vasectomy in addition to the back sugery-and urology isn't their specialty.
I do know that there are some guys on the board who have low testoterone levels because of the heavy duty pain meRAB that they take-and have taken over a long period of time. You didn't say how long ago your hubby had the surgery...if it's a recent event, his nerves can still be twitching and causing "'issues".....but not sterility. You would need to have a test done at the doctors office to determine if he is truly sterile.
