I can elaborate a ton on this vas/reversal subject.
I've seen many men hem, and haw about why reversals fail, reversal this, reversal that. A lot of what people are saying is not medical science, nor been proven in any way.
Given the fact that my first reversal was basically a failure out the gates, and what @jsh is asking about the 9800 dollars, it's all part of why I wish I had gone to ICVR the first time. I didn't have time to be screwing around with anyone of a lesser caliber. This is my life we are talking about, not some reversal surgeons paycheck.
Part of Dr Marks pre reversal questionnaire was, how easily do you scar when you get cut, or injured? I didn't think much of it then, but think more into it now days.
Dr Marks described my inner lumen as wispy. We are talking about something that's comparable to a human hair far as diameter, but it's not rigid like a human hair. Imagine the tini bit of scar tissue required to close this repair off.
I know stents have been tried in the past in an attempt to keep the repair open with no luck. This part of the body wants to scar back closed once it has been breached by vasectomy. I don't have all the answers/facts far as why some reversals stay open, and some do not other than "what seems to be" the obvious.
I've always said I believe my own immune system has been part of my PvP/s since my beginning's. That said, it just reinforces my theory's on why I can't seem to keep a reversal open, and perhaps in other cases as well.
I also had the butcher version, closed ended vasectomy. My unorthodox vasectimist removed more of the vas than he was supposed to. He wasn't thinking about me, he was thinking about himself far as being sued if I became fertile again via natural recanalization. I didn't know any better back then.
I lost even more vas at the time of my first reversal. A recipe for more disaster IMO far as staying open indefinitely on a redo reversal.
Do I scar easily? I wouldn't say so, but I do heal extremely well from just about anything. Do I have scars on my body from previous injuries? Yes I do, and I think that's pretty normal.
The average sperm count of a reversed man that gets his partner/wife pregnant after a vasectomy reversal is around 5 million. At the peak of my redo reversal, my count was around 160 million/80% motile. I didn't have poor numbers by any means.
I've had people say it was tobacco, cannabis, mountain dew, amongst other things that caused my second reversal to fail. While this is easy say, there is no medical proof for such allegations. The staff at ICVR offered me a mountain dew, water, or other soft drink within minutes of me coming to in the recovery room. I took them up on the mountain dew, lol.
Reversal is a crap shoot IMO. You never know what your gonna get. I might not be fertile, but I still reap the rewards of a full clean up, and being put back close as possible to my natural state again. I have no regrets far as going down the reversal road other than not going to ICVR the first time. If I thought a third reversal would stay open indefinitely, I'd give it a shot again, but I'm smarter than that.
Here's a couple links to some interesting facts.