I strongly recommend finding a urologist who specializes in penile therapy. I know someone who went through focal, radiation surgery, more radiation and hormone therapy...and after all of that and working with a sexual function doctor, is now back in business and very happy. He went through some very dark times, but is doing great now.
From what I've learned from various penile therapy guides from centers across the country, there are two uses for the pump. One is for therapy to help deal with penile shrinkage. For that process, it's not absolutely necessary pump up to a full erection, just to the point where you don't feel pain. You pump to the point that doesn't induce discomfort, let it sit for a bit and then release pressure. Repeat five times. Do daily.
My concern was that I didn't want so much shrinkage that I would have to pee sitting down, which sounds like it happens to some folks. I actually find that sitting down to pee is more probemamtic because I have less length and end up aiming straight ahead rather than down into toilet. So, glad to be able to pee standing up.
The second use of the pump is to get a firm enough erection for penetration using a restriction ring.. I'm not up to this phase (just three weeks post surgery, so way to early to go there). But, I will say that I did test out a pump before surgery so I knew what it would be like before I lost function and after. I purchased a Vacuerect, which is a FDA approved manual pump.
Post surgery, i have started pumping. I do believe it has helped reduce some of the initial penile shortening, but it will take time. I know for a fact that I also lost some girth. Perhaps that will change over time. I don't know.
Don't give up yet...you just might need some expert medical guidance. Hang in there...not an easy path.
@fritzo thanks for your comments but believe me I’ve tried it all had a pump 3 months after surgery, have had many discussions with Drs. I’m reaching the 2 yr point when many Drs. Say if you’re going to be able to enjoy sex again it should happen by the 2 yr mark . Even though I had a top Dr at MGH in Boston and he said he only had to a little nerve damage I don’t feel anything the few times I had a half ass erection, I even gave to ask am I in ? Pretty sad situation, good luck to you.