Background: Lack of adequate development of the midface is a not uncommon facial developmental deformity and is most commonly seen in certain ethnicities. In its most significant form combined orthodontic-orthognathic surgery approaches are needed to treat both the functional and aesthetic sequelae from a midface that lacks adequate forward projection.
Far more commonly are natural midface deficiencies that are not associated with a malocclusion. (or they have been orthodontically corrected and did not require surgery) These more aesthetic midface deficiencies can occur most prominently at the nasal base or may involve the entire skeletal midface from the infraorbital rim down to the maxillary alveolus.
Aesthetic augmentation of these more complete midface recessions has historically been limited. Localized augmentations are available using standard cheek, infraorbital and pyriform aperture implants. But these do not create a cohesive and uniform augmentation across the entire midface and controlling thicknesses and exact shapes is not really possible The custom midface mask implant approach overcomes these disjointed standard implant issues.
Case Study: This male with an ethnicity from central Asia desired a complete midface augmentation. Using his 3D CT scan a implant design was made covering the entire midface with limited lateral cheek extensions. The goal was to pull the complete midface forward but not add side cheek width.
Because of the location of the infraorbital nerve the midface implant was designed as three pieces…bilateral infraorbital-malar segments (10cc volume) and a lower side to side maxillary segment which crossed under the nasal base. (5cc volume)
Under general anesthesia and through an intraoral vestibular incision (1st molar to 1st molar) which preserved a thick musculomucosavl cuff of tissue, the entire midface was degloved. Around the pyriform aperture it was important to not violate the nasal mucosa. The infraorbital nerve was circumferentially dissected for complete mobilization and access to the infraorbital rim above it.
The custom mask implant was packaged in three separate pieces as per the design. The inferior segment was prepared by the placement of perfusion holes using a 4mm dermal punch.
The superior segments of the midface mask implant were initially placed and positioned based on their shape around the infraorbital nerve. The inferior segment was then inserted and assembled per the interlocking geometric shapes. Once good apposition was obtained between the superior and inferior segments screw fixation was applied. Screws were also placed at the canine fossa areas of the inferior segment.
After antibiotic irrigation a double layer closure was done with resorbable sutures of the muscle and mucosa.
The custom midface mask implant provides unparalleled augmentation of the complete facial skeleton from the infraorbital rim down to above the level of upper teeth. It has a ‘Lefort III-like’ effect minus any occlusal movement. Being to be placed from inside the mouth it is a scarless procedure. The patient should expect some prolonged numbness of the upper lip and side of the nose due to the stretching of the infraorbital nerve. But full recovery should occur. Stiffness of the smile will persist until the swelling subsides and the tissues soften. In my experience to date I have not had any infections or need for postoperative implant adjustments.
Case Highlights:
1) The entire midface can be brought forward by onlay augmentation of its entire bone surface by a custom implant design.
2) Because of the infraorbital nerve the custom midface mask implant must be designed and placed in three pieces.
3) An exclusive intraoral approach can be used to place the custom midface mask implant.
Dr. Barry Eppley
Indianapolis, Indiana