Operation was in-and-out of hospital in one day. Then had a big cellophane-like bandage on neck and shoulder area that had to be kept clean and air-tight for 2 weeks. It was a good bandage though, just had to patch it up occasionally with new layers of cellophane-stuff. Main possible complication would be infection (worse case is that device then has to be removed) or some people have side effect where it feels like their throat is ticked and they cough when device activates. We didn't have any problems.
Then once its all healed they turn the device using nfc wand thing and then slowly increase the power bit by bit over several months. There are various timing and frequency settings that can be experimented with.