Background: Custom designed facial implants provide a great degree of facial change. The larger surface areas of custom implants and preoperative control of their shape and dimensions allows for a major change in facial shape if desired. To do so augmentation of the midface line (infraorbital-malar) and entire jawline are often done together as these represent the bony convexities of the face. Thus custom infraorbital-malar and jawline implants are often done during the same surgery.
Custom jawline implants in my practice are very common. The three projecting points of the jawline (chin and jaw angles) are augmented and then connected as a single implant. The amount of chin augmentation can be considerable and attention has to be paid to the the overlying soft tissue chin pad and whether it can handle the implant load and adequately stretch over it. Horizontal increases up to 10mms are usually not a problem but greater advances than that can almost never be done unless one has a pre-existing chin implant. This serves to tissue expand the chin pad and allow for safe implant placement.
One approach to a large chin augmentation in custom jawline implants is to mesh a sliding genioplasty with a custom implant overlay as part of the rest of the jawline implant behind it. This lessens the ‘implant load’ in the chin area by making the augmentation partly done by the bone.
Case Study: This young male had an existing chin implant and he now desired both greater chin projection as well as an entire jawline augmentation. However he did not want the large chin augmentation to be done all by implant and requested a sliding genioplasty to replace the augmentation done by his existing chin implant . The additional chin augmentation was to be done by a jawline implant overlay. To match the midface shape to the larger jawline size, he also wanted custom infraorbital-malar implants.
Using a 3D CT scan the custom midface and jawline implants were designed with the objectives of matching what had been created by computer imaging of pictures.
The design process incorporated a sliding genioplasty with the jawline implant overlay. The insert of the advanced bony chin segment could be seen in the backside of the chin part of the jawline implant.
Under general anesthesia and through an intraoral incision (which was how the original chin implant was placed) the Medpor chin implant was removed in two halfs. Subperiosteal tunnels were made back along the jawline to the angles to make the complete implant pocket which was aided by two posterior vestibular incisions. A sliding genioplasty as then performed with an 8mm horizontal advancement and 2mms of vertical lengthening with plate and screw fixation. The custom jawline implant was placed in a back to front direction in two halfs to protect the integrity of the mental nerves. The split chin sections of the jawline implant was brought together over the advanced chin bone with a perfect fit and secured with long 2.0mm screws per side to the underlying advanced chin bone. To improve vascular perfusion through the implants and to add a reservoir for antibiotics, multiple 6mms perfusion holes were placed with a dermal punch and loaded with antibiotic powder. Lastly the jaw angle potions of the implants were positioned and secured with percutaneously placed screws.
The concept of combining a sliding genioplasty with an implant overlay is not new whether it is done by an isolated standard chin implant or a larger custom jawline implant. Computer designing makes the latter possible with a good fit between the bone and implant.
Case Highlights:
1) It is common to have custom infraorbital-malar and jawline implants placed during the same surgery for a maximal facial enhancement effect.
2) To limit the implant load on a large chin augmentation, a sliding genioplasty can be done with a custom jawline implant overlay.
3) Preoperative computer designing can make the amount of chin bone movement to fit into the implant overlay.
Dr. Barry Eppley
Indianapolis, Indiana