Welcome to five years ago people. This is nothing new. Steve Haworth has been doin\' this stuff for years, I know, as when I was heavy into the body modification stuff I was goin\' to contact him and get some.
I doubt you need much for a subcutaneous implant... no local, nothing necessary. Just a small incision, and slip in the item, just like with early barbs and stuff.
For smaller implants, some artists use a procedure similar to the beading procedure above, but this is not the norm, nor is it even an option for anything much larger than a small bead. The majority are inserted using a surgical method, roughly simplified as:
1. The final location of the implant is drawn on the skin as a reference.
2. An incision is made a small distance away from where the implant will rest.
3. Through this incision, a "pocket" is formed using dermal elevators.
4. The implant is inserted into this pocket.
5. The incision is closed using sutures or suture tape.
http://www.bmezine.com/ ^^ Is your friend.