A patient-specific midface implant can be designed to create an advancement/augmentation effect across much more than the conventional malar eminence. The key distinction is that it changes facial skeletal contour, but it does not literally advance the maxilla, dentition, or airway the way an osteotomy does. Alloplastic augmentation has been described as either an adjunct to orthognathic surgery or, in selected patients with satisfactory occlusion, a way to simulate some of the external contour effects of skeletal advancement. It is the only non-osteotomy method to pull the midface forward.
For a comprehensive design, I would think of it as a custom extended midface implant, potentially incorporating the infraorbital rim ? malar/zygomatic body ? submalar region ? pyriform/paranasal region. The anterior-medial component is particularly important if the objective is an apparent midface advancement rather than simply wider/prominent cheekbones. Depending on anatomy, the design can transition around the lateral nasal/pyriform aperture to provide paranasal support while feathering laterally over the maxilla and zygoma.
A useful design concept is differential projection rather than uniform thickness: relatively more anterior projection in deficient paranasal/maxillary areas, controlled projection at the infraorbital rim, and carefully tapered malar/submalar augmentation. That can make the entire midface read as anteriorly positioned rather than producing an obviously “implanted cheek” appearance. While patient-specific CAD/CAM implants have been used specifically for residual midface deficiency, including combined treatment with orthognathic advancement, I find that many such midface implants are for patients who have milder forms of midface deficiencies where skeletal advancement is not needed or not warranted.
Material options include Silicone and PEEK as the most commonly used. That choice comes down to implant size and design as well as patient preference. Both can be successfully used and experience surgical technique permits both implant materials to be successfully placed with a low risk of malpositioning.
The biggest planning question is whether the deficiency is primarily contour or true maxillary retrusion. If there is Class III malocclusion, functional maxillary deficiency, airway considerations, or a large sagittal discrepancy, an implant shouldn’t be viewed as a substitute for Le Fort advancement. If occlusion is satisfactory and the problem is predominantly skeletal surface contour—flat infraorbital rims, deficient paranasal support, negative-vector relationship, malar/submalar deficiency—a custom implant becomes considerably more compelling.
In some cases skeletal advancement and implant augmentation can be complementary rather than mutually exclusive. The question in these cases it should they be done concurrently or staged…osteotomy first and implant secondarily.
Dr. Barry Eppley
Plastuc Surgeon