The definitive aesthetic jaw augmentation procedure is the custom jawline implant. It provides a complete three dimensional change to the lower face in a predetermined planned manner. But as part of the preoperative planning process a complete assessment of the lower jaw bone can be seen in the 3D CT scans needed for the custom jawline implants design. This view of the surface of the mandible (lower jaw) is unparalleled compared to how it it most commonly seen in panorex x-rays and even 2D CT scans. This beautiful view of the jaw bony topography can provide some valuable information not only for preoperative planning but also for intraoperative surgery.
One of the key areas to look at in a 3D CT scan is the bony jaw angles particularly in males. The strength of the attachment of the masseter muscles can be seen by their ligamentous attachments and the influence on the shape of the jaw angle along the inferior border. Strong ligamentous attachments, which can be difficult to release intraoperatively and come with an increased risk of masseter muscle dehiscence as a result, can be identified by their bony projections along the inferior and posterior rim of the jaw angles. Such strong ligamentous attachments are often associated with a pronounced antegonial notch in front of the masseter muscle attachments along the inferior border.
Not surprisingly such ligamentous attachments of the masseter muscle correspond to a similar effect on the inside of the jaw angles for the lateral pterygoid muscle insertions. As the pterygo-masseteric sling works in concert for lower jaw movement it is not a surprise the bone reflects a near mirror image on the inside on how it appears on the outside.
When one sees such strong ligamentous attachments at the jaw angles in custom jawline implant designing, the consideration of limited vertical implant lengthening needs to be strongly considered. This does not mean that making an implant design that significantly lengthens the jaw angles will always result in postoperative masseteric muscle dehiscence but the risk is definitely increased.
Dr. Barry Eppley
World-Renowned Plastic Surgeon