Facial Implants Chicago | Chicago Illinois Cheek Implants

FACIAL IMPLANTS

Preoperative assessment

The hypoplastic chin is the most common indication for chin augmentation. On frontal view the face can be divided into thirds, with the lower third spanning from the subnasale to the mentum. Aging results in loss of vertical height of the mandible. On lateral view, a vertical line can be dropped from the lower lip. In females the chin should be 1-2 mm posterior to this line. In males, the chin should lie at the same level as this line. There are a number of techniques to analyze chin size and projection. (See Table 1)

Patients’ occlusion should be assessed preoperatively to ensure orthognathic treatment is not necessary. Type I occlusion is when the mesial-buccal cusp of the maxillary first molar contacts with the mandibular first molar's buccal groove. Type II occlusion is when the maxillary first molar is anterior to the buccal groove (an overbite), and Type III is when the maxillary molar is posterior (an underbite).

Analysis of the malar and submalar region is much more complex and requires three dimensional planning. The submalar triangle is the area below the malar eminence and the location of many facial deficiencies. Binder classified patterns of midfacial deformity and their resultant augmentation required. There are a variety of methods of analyzing the midface and its projection. (see Table 2)

Procedure

Chin implantation can take place by an external or intraoral route. The extraoral approach has the advantage of not contaminating the implant through the oral cavity. The intraoral approach avoids an external scar. Implants placed intraorally tend to “ride” high postoperatively, in part due to difficulty fixating the implant. The surgeon should be aware of the position of the mental nerve, which emanates from the bone approximately 1 cm above the edge of the mandible and approximately 2.5-3.5 cm from the midline, lying in the vertical plane between the first and second premolar.

Typically, malar and submalar implants are placed by an intraoral route. An incision is made along the upper gingivobuccal sulcus and an elevator is used to lift the periosteum off the face of the maxilla. The masseteric fibers are released off of the face of the maxilla.

The infraorbital nerve is avoided as it exits the infraorbital foramen 4-7 mm below the inferior orbital rim on a vertical line that descends from the medial limbus of the iris. A tight periosteal pocket is created, small enough to fit the implant tightly. The implant can be further fixated with a titanium screw, a resorbable suture, or a temporary external suture and bolster.

Complications

Complications are rare and include hematoma, infection, nerve paresthesia (transient or permanent), and motor nerve injury. No study has shown a change in infection rates in extraoral versus intraoral approaches.

EPTFE (Gore-tex) is an expanded, strongly hydrophobic, fibrillated polymer that can be produced in sheets, three-dimensional strands, and suture material. EPTFE has been associated with infection, extrusion, and scarring. EPTFE has been used with success in a recent study with only 0.62% of implants requiring removal for infection. EPTFE has the advantage of being soft, with minimal encapsulation and bony resorption.

Silicone is a relatively inert substance which has more encapsulation than EPTFE. Bony resorption increases with overlying muscle action translating to implant mobility. Therefore, the implant should be secured in a tight pocket with either sutures or titanium screws. In addition, subperiosteal placement will increase bony resorption. Well-positioned implants with osseous erosion should not be replaced. Silicone implants are easier to place than EPTFE due to less flexibility at the peripherial portion of the implant and higher resistance to crushing.

Medporr

Malar and submalar implants can result in injury to sensory nerve (V2) or motor nerve (buccal or temporal branch), albeit a rare event. More commonly, midface implants may result in asymmetry due to preexisting facial skeleton imbalances.

REFERENCES

Tobias GW, Binder WJ. The submalar triangle: its anatomy and clinical significance. Fac Plast Surg Clin North Am 1994;2:255.

Godin M, Costa L, Romo T, Truswell W, Wang T, Williams E. Gore-Tex chin implants: a review of 324 cases. Arch Facial Plast Surg. 2003 May-Jun;5(3):224-7.

Gonzalez-Ulloa M: Building out the malar prominences as an addition to rhytidectomy.

Plast Reconstr Surg 1974 Mar; 53(3): 293-6

Hinderer UT: Malar Implants to Improve Facial Proportions and Aging.  In: Stark RB

ed.  Plastic Surgery of the Head and Neck.  New York: Churchill Livingstone

1987.

Matarasso A, Elias AC, Elias RL. Labial incompetence: a marker for progressive bone resorption in silastic chin augmetatin. Plast Reconstr Surg 1997, 98:1007-1014.

SUMMARY

Knowledge of the advantages and disadvantages of each facial filler will provide the facial plastic surgeon an armamentarium of options in addressing facial effects. Appropriate preoperative assessment will allow the surgeon to determine facial implant size and maximize patient satisfaction.