I can only put my humble opinion in here…
During installation? This should be no problem, as long as you go to someone who knows what he does. Implanting things on the back of the hand is not that unusual, the skin separates nicely, and like I said - as long as your installer is competent, damage during installation is very unlikely.
I may just be a bad example, dunno… but for me, the flexNExT was just a bit too big for my hand. The rim always stood out on the sides, it was pretty visible and obviously not adapting to the slightly curved shape of my hand. No idea if it would help to bend the implant a bit before installation, but at least for me, I always had a small edge with the inherent danger to catch on it.
If an implant is obviously (even just a little bit) too big, the danger of causing damage is alwas there, and that’s what possibly finally happened for me.
The other downside of placement on the hand is that the healing period is a bit longer, simply because you have a lot of movement there. Better plan some holiday when getting it done, and prepare for it being bitchy after you do something with your hand for quite a while 