Background: The jaw angles of the lower jaw represent two-thirds of the lower face. Despite occupying a large surface area and providing significant soft tissue support to the overlying soft tissues, the jaw angles have historically been less aesthetically recognized than that of the singular projecting chin. This is understandable given that the chin is the most anterior aspect of the lower jaw and it creates the most visible separation of the face from the neck in any viewed angle.
As a result aesthetic augmentation of the chin has a wide variety of implants available for use and the surgical technique for their placement is well established. Conversely jaw angle augmentation techniques are less well known and the implant options more limited to do so. Widening jaw angle implants have been around for three decades and for many men this is a satisfactory jaw angle augmentation method. But for women this is far less frequently successful as their aesthetic sense is for less width and more vertical length. Much like the chin the aesthetic needs are different for women than men.
The surgical placement of the vertical jaw angle implant poses challenges that do not exist for a widening jaw angle implant. To place the vertical lengthening implant it is necessary to raise the periosteum off of the bone along the inferior border of the angle. To do so any osteoligamentous attachments must be released with the periosteum elevation. Failure to do so will result in jaw angle malposition with the implant sitting at a 45 degree angle, creating undesired width and inadequate vertical length. Fortunately in females the soft tissue attachments to the bony jaw angle are less adherent than that in men.
Case Study: This female was to undergo a sliding genioplasty and also wanted jaw angle augmentation as well. She wanted a strong well defined jawline an preferred to have a result that was strong and not subtle…even though she was a small petite female. With a high rounder jaw angle shape, the use of the vertical lengthening jaw angle style was appropriate for her aesthetic goals.
Under general anesthesia and after completion of the sliding genioplasty, the jaw angles were approached intaorally with posterior vestibular incisions. The jaw angle bone was exposed by gentle subperiosteal dissection all the way down along the inferior and posterior borders. The jaw angle were inserted and positioned with the lip of the implant under the inferior border. The key to vertical jaw angle implant positioning is that the implant must be seen to lay vertically flush against the bone surface. Double screw fixation was applied in each side through a percutaneous technique. A two layer musculocutaneous closure was done with slow resorbing sutures.
Her two year result shows well defined jaw angles, strong for a female, but exactly what she wanted.
The selection and placement of jaw angle implants is more challenging than that of chin implants for multiple reasons. First it is two implants and not just one that are placed independently of each other. Secondly their placement is way back inside the mouth with the working end of the implant at the furtherest distance from the incision. Lastly, their placement is under the masseter muscle which creates strong forces on the implant. All of these factors requires careful attention to placement and a method of implant fixation.
Case Highlights:
1) Most female jaw angle augmentations are more about a vertical dimensional increase than width to create a more defined back part of the lower jaw.
2) The standard vertical lengthening jaw angle implant requires release of the osteocutaneous ligaments of the jaw angle for proper implant positioning. Screw fixation is needed to keep it there.
3) The size of the vertical lengthening jaw angle implant determines how strong or defined the angle will appear. Most women do well with a medium size if they want a strong jaw angle appearance.
Dr. Barry Eppley
Indianapolis, Indiana