As someone who has had disc surgery (and did so at a younger age than Romo), the notion that one no longer has back issues after surgery is a reach. I had surgery after experiencing pain and/or numbness down my right leg. I had a L5-S1 disc issue. I had surgery that removed part of the disc (they did not remove all the disc because of proximity to the spinal cord). I was playing football and had someone put their helmet into my lower back that had me sidelined for a week with bad back pain and bruising. That was the cause of the eventual bulging disc.
The surgery was largely successful and I no longer have the constant leg pain/numbness. However, given there is a small part of the disc still in my spine, from time to time, if I sleep wrong or sit wrong, the disc can compress the spinal cord and I will get that numbness back in the leg. But often in a few hours or a day or two it goes away and it's infrequent.
I also recall the conversation I had with my surgeon, who had operated on some prominent athletes as well. He said the only real side effect for someone like me (who had surgery at 21) is that going forward, while in my 20s, I'd essentially have the back of someone in their 30s. And when I was in my 30s, I'd have the back of a 40 year old and so on and so on.
So the idea that Romo is completely free of back issues because of surgery is a misnomer IMO. If I recall, he was even put on a limited practice schedule for his back even well after his recovery period was up. The logic was to limit activities that could lead to back discomfort.