Custom jawline implants provide the most effective and complete method of creating a more distinct and augmented lower third of the face. Because of its connected design from one jaw angle to the other (wrap around) it augments the entire inferolateral border of the jawline. While creating such jawline implants creates impressive changes on the planning 3D CT scan, their potential effect can not be fully realized unless they are placed fairly close to how it is designed on the bone.
Unlike standard jaw augmentation implants (chin and jaw angles) which are smaller and unconnected and fit easily through their respective separate incisions, a custom jawline implant poses far more challenges in its placement. Mist custom jawline implants can be placed as an intact one piece implant using the three standard anterior and paired posterior incisions. The success of that approach is based on whether the tallest part of the implant (jaw angles) can fit safely underneath/through the smallest/most narrow part of the subperiosteal pocket that is created. This is the area of the lower jaw where the mental nerve is located in which the distance between the bony foramen and the inferior edge of the jawline determines this potential limitation.
While in most jawline implant this is not usually a limiting factor for its intact placement, there are situations when it is. This is seen is very large custom jawline implants being placed the first time AND the larger jawline implants are being done as a replacement for a smaller jawline implant. (the capsule of the prior implant decreases the flexibility of the tissue tunnel.
In these situations a particulated implant placement technique needs to be used. In other words the implant will need to be cut into multiple pieces, passed through the incisions and then reassembled once inside the implant pocket. This can usually be suspected during the implant design process in which the cut lines of the planned sectioned areas can be made onto the implant. The most useful approach with this technique in my experience to place a geometric cut line imprint at the anterior end of the jaw angles. This then allows the thinner longer section of the implant to be passed under the nerve from the anterior incision.The larger thicker jaw angle section can then be safely placed through the posterior intraoral incisions.
During surgery the jawline implant is initially separated along the designed geometric cut lines. The longer chin section is placed first through the anterior incision. (usually submental) The jaw angle pieces are then placed into the pocket intraorally and then fit into the anterior section of the implant on both sides like a puzzle piece. Once the implant sections are interdigitated a screw is placed on each side of the split. Interestingly this sounds simple but is a lot harder to execute successfully than it appears on the design.
I don’t advocate ever cutting up a custom jawline implant if it can be avoided. Having three unconnected pieces as opposed to one solid piece makes placement over the always difficult jaw angle region inherently more difficult/unpredictable. But given the choice between potentially causing a permanent mental nerve injury vs the risk of some implant malpositioning has a bette chance of secondary recovery/correction.
Dr. Barry Eppley
Indianapolis, Indiana