In a rather gory fic I'm working on, a character has a pair of horns surgically attached to her skull against her will (it's a symbolic thing). I'm unsure how best they could be attached without puncturing the skull. Googling "attach skull implants" and "attach skull plate" brings up some surgical information, but nothing useful. The setting has plenty of techno-magical stuff, so I can get handwavey if necessary.
EDIT: I'm specifically not talking about subdermal implants; these are meant to be attached to the skull itself and poke straight through the skin. Here is a picture of what I mean, which is incredibly bloody so be careful:
http://s9.postimg.org/k6kwxngov/traptrolls.png