The placement of jaw angle implants has many unique aspects from other facial implants. It requires dissection in the most posterior part of the face done from inside the mouth making access and visibility challenging. It requires the largest muscle on the face to be lifted off the bone (masseter muscle) to place and position the implant. And certain types of jaw angle implants (vertical lengthening types) require that about half of the implant is not situated on the ramus portion of the mandible.
Because of these unique characteristics the success (and failure) of jaw angle implants are related to proper positioning and stabilization of them. Unlike many facial implants where fixation of the implant to the bone may be viewed as a ‘luxury’, I view fixation of jaw angle implants as a virtual necessity. They can become so easily displaced right after wound closure (push back of the masseter muscle causing them to slide forward) that the only postoperative assurance of implant positioning is to screw them into place.
There are multiple methods of screw fixation but the simplest and most effective is a percutaneous technique using 1.5mm self-tapping screws. Screws are optimally placed from a perpendicular orientation to the bone and this is of paramount importance when the screw is self-tapping. (not requiring a drill to place a hole in the bone) Using a small 3mm skin incision from the side of the face over the implant allows the screw driver to be inserted through the skin and masseter muscle down to the implant’s surface. The screw is then placed on the screw driver and inserted through the implant to the bone. Usually only a single screw is needed that is no more than 5mms in length. (thus avoiding hitting any tooth or nerve structures that lie deeper)
Patients are understandably nervous about a facial ‘scar’. But this nick incision is so small that it heals in a scarless fashion. The initial incision is closed with a single 6-0 plain gut suture.
Dr. Barry Eppley
Indianapolis, Indiana