Another thing I probably could have made more clear is where and what are you nerving - how far up or down the nerve are you targeting? An older vet who has seen the evolution of this procedure would be the best person to ask, but my understanding is we’ve gotten a lot better about more targeted, localized nerving.
Theoretically, at one extreme, you could “nerve” at the spinal cord (like an epidural) (I know you can’t really do this, it’s just a thought exercise), and then really not know if you have another injury in a limb, or you can nerve a teeny tiny little nerve in your figure in which case you would be very well aware of other injuries 99% of the time.
My understanding is that historically we’ve just nerved the bigger nerves, causing, say, most of the foot to be de-nerved. But nowadays we have more knowledge to do more targeted de-nerving, minimizing the chance of off-target effects (i.e., not knowing about other limb injuries).
Also people don’t always update their knowledge of medicine - e.g., electroshock therapy of today’s modern era is very different from what it was 30 years ago, but most people aren’t aware of that, and still see it as a brutish practice (if they know it’s being done at all). It’s similarly used as a “last resort” for people with treatment-resistant depression (i.e., like de-nerving, in some ways).