Implants, Soft Tissue, Gore-Tex 

Facial augmentation can be undertaken for reconstructive or cosmetic purposes. Patients seeking facial augmentation are interested in enhancing a specific facial area. This area may have been scarred or altered by trauma, or the patient may desire an increase in the volume of tissue present in an area of the face for aesthetic reasons. Most often, patients seek these treatments to improve their appearance. See the image below.

A variety of facial implant materials can be used. Autogenous material, such as a patient's own adipose tissue, can be harvested via syringe liposuction and injected into the desired area. Other autologous materials include dermis, dermal-fat grafts, fascia, and galea. Human-derived donor materials for facial augmentation include AlloDerm, Cymetra (which is AlloDerm in a particulate micronized form), CosmoDerm and CosmoPlast, Fascian particulate fascia, and Fasciablast (which is fascia in different forms, including strands). In addition, xenografts, such as bovine-derived collagen fillers like Zyderm and Zyplast, are available. Dermalogen, a homologous compound composed of different forms of human collagen, is no longer available.

More popular dermal fillers include different forms of hyaluronic acid such as Restylane, Perlane, Juvederm, and Hylaform. Synthetic materials include silicone (such as Silskin), polyalkylimide (such as Bio-Alcamid), hydroxyapatite (such as Radiesse), polylactic acid (such as Sculptra), and polymethylmethacrylate (such as ArteFill). All are useful for structural augmentation of the face. Other fillers are available in countries around the world.

In traditional discussions of facial aesthetics, the face is divided vertically into an upper, middle, and lower third. The upper third extends from the trichion, defined as the intersection of the midsagittal plane of the head and the hairline, to the brows or superior orbital rim. The middle third spans the brows to the base of the nose (ie, the area from the glabella to the subnasale). The subnasale is where the upper lip skin and the columella meet. The lower third of the face extends from the base of the nose to the chin (ie, the subnasale to the menton). The menton is described as the lowest point of the soft tissue of the chin.

As an alternative, the face may be divided into an upper and lower half at the lower eyelid, or the face may be described excluding the forehead since hairlines can be variable. The latter description can be especially useful in males with a receding or absent hairline. In this description, the portion from the nasion to the subnasale comprises 43% of the lower two thirds of the face, and the portion from the subnasale to the menton comprises 57% of this area. The nasion is found in the midsagittal plane and is the point where the deepest depression of the nose occurs.^[1]

Horizontally, the face is divided into fifths from ear to ear. Tolleth has remarked on the classic artist's system of the face being 5 eye widths wide and 8 eye widths long.^[2] The eyes are separated by slightly more than 1 eye width. The width of the neck should be in alignment with the lateral canthi of the eyes.

The profile view of the face can reveal a concave, convex, or straight appearance. Additionally, structures of the face form various angles that can cause a protuberant, flat, or retrusive appearance. The facial shape can appear oval, round, or square and can vary in the degree to which it meets this categorization. The appearance of the head can also vary.

In attempts to standardize descriptions of facial features, the standard, or template, must accommodate ethnic variability and must be applicable to both males and females. Faces that adhere to these templates are often considered beautiful or aesthetically appealing.

Assessment

Aesthetic assessment of a subunit of the face is of paramount importance to implant placement planning in order to achieve the desired augmentation. For a maximal surgical result, ascertain if the client had prior augmentation, and, if so, determine the materials used. Perform an assessment of the structural effect, note the client's satisfaction with the prior procedure, and establish any untoward outcomes.

Some patients may desire augmentation that is not medically advisable. Others have unrealistic expectations. The surgeon must be willing to frankly discuss such concerns and decline proceeding with surgery if these concerns are not resolved.

Soft tissue augmentation often involves augmentation of an aesthetic subunit. For example, in upper lip augmentation, though the upper lip is part of the lower third of the face, not focusing only on the area for which treatment is being sought is important. All of the facial structures and the overall appearance of the face must be considered. The effect of augmenting one area must be assessed, as it will affect other areas. Maintaining a harmonious balance is important in enhancing a person's features.

Indications

Soft tissue augmentation using polytetrafluoroethylene (PTFE) can be performed in the following facial areas:

• Nasolabial (melolabial) folds
• Lips
• Dorsum of the nose
• Glabella area
• Premaxilla
• Anterior nasal spine
• Malar area
• Midface area
• Mentum
• Mandible

PTFE is a synthetic polymer that is carbon and fluorine based (CF2-CF2) and nonbiodegradable in the human body. It is biologically inert, adding to its appeal for use as implant material. Teflon is a type of PTFE in a paste form that has been used in the treatment of vocal cord disorders; however, this use has largely been abandoned, as injection difficulties and marked inflammatory reactions have limited Teflon's application in facial plastic surgery.

Proplast, originally developed in 1970, was used to coat orthopedic joint implants. Later, Proplast II was used in facial plastic surgery. When used in temporomandibular joint (TMJ) surgery, Proplast, under the strong shearing forces caused by mastication, breaks apart and induces a significant inflammatory reaction. The Food and Drug Administration (FDA) ultimately recalled Proplast and Proplast II.

Gore-Tex is a type of PTFE that has been used in humans as an implantable material for more than 26 years. It was first used in 1971 for human vascular grafts. In 1983, Neel used this polymer in rabbits and recommended its use in facial plastic surgery. Because vascular ingrowth is limited, this polymer has been shown to be only minimally integrated with the surrounding tissues. The pore sizes range from 0.5-30 microns, which is not an ideal diameter for macrophage migration and tissue ingrowth but can be a favorable environment for bacterial invasion and infection. Sclafani and Romo have reported a 2% rate of infection.

Expanded polytetrafluoroethylene (ePTFE) is a woven polymer consisting of fibrils of PTFE that are connected via nodes of PTFE, creating a structure similar to mesh. ePTFE is FDA approved for facial augmentation.

Originally, Gore-Tex strands used in the lip and nasolabial fold were not without problems. At times, the implants were palpable or extruded.

The tubular form of Gore-Tex, referred to as SoftForm (FDA approved for clinical use in 1997), is hollow to allow for vascular ingrowth through the tube. Nonetheless, problems remain. These include palpable implants and shortening of the implant over time. In the past, implant shortening was due to the implants being manufactured with insufficient length and diameter. The original implants were 7 cm in length and 3.2 mm in diameter. Newer implants measure 4.0 mm in diameter and up to 9.0 mm length. To attempt to prevent shortening over time, implants for lip augmentation now measure 4.8 mm in diameter and 11 cm in length. UltraSoft was launched in July 2001 by Tissue Technologies, which also created SoftForm; UltraSoft is reportedly softer than SoftForm.

Regardless of which type of implant is used, the polymer must be deposited deep in subcutaneous tissue or even in the subperiosteal area. Schoenrock and others have shown that a more anterior placement closer to the dermis will result in a more pronounced inflammatory process.

Newer, solid Gore-Tex implants, called Gore-Tex S.A.M. (subcutaneous augmentation material), are available as solid tubes, patches, preformed shapes, and custom-made shapes, dependent on the area to be treated.

For tubular ePTFE, the augmentation site, such as the melolabial (nasolabial) fold, is prepared with an iodine-based solution. An infraorbital nerve block using 1% lidocaine with 1 part per 100,000 parts epinephrine and 0.5% Marcaine in a 50/50 mixture is used for anesthesia. In the nasolabial fold, a small puncture incision with an 11 blade is made, extending approximately 2 mm. To introduce the implant beneath the dermis, a Keith needle (for strands of ePTFE) or trocar is used. The SoftForm implant should be 7.0-9.0 cm long and 4.0 mm thick. Push the needle to the desired exit spot and make an incision of similar size to the entry wound. Externalize the needle or the trocar and cut the polymer to size so that the distal end is not protruding from the entry wounds. Skin is closed with 6-0 white nylon, and Steri-Strips are applied to the skin. Sutures are removed after 5-7 days.

In the lip, the technique for the strands is different from the technique for the SoftForm version of ePTFE. The entry and exit sites are approximately 2 mm medial to the commissure. In the lower lip, place the incision horizontally, medial to the commissure and at the vermillion border. With smaller implants, such as the 3.2 mm implant that was used in the past, the recommendation was to place one implant in the lower lip and 2 implants in the upper lip. However, the current recommendations for SoftForm use are one implant for the upper lip and one implant for the lower lip. These should be at least 9.0 cm long and 3.2 mm thick (11.0 cm long and 4.8 mm thick for greater augmentation).

Implant placement in the lip also varies depending on the type of implant used. If the strands are used, gently stretch the tissue of the lip. Do not stretch the lip tissue if using SoftForm. Lip implants are placed to enhance the vermillion border and augment the lip's fullness. If using SoftForm, the larger diameter implant accomplishes these goals. If strands are used, the number and exact placement can be varied to not only enhance the contour but also enhance the degree of augmentation.

Glabellar creases run vertically. Place incisions for the entry and exit wounds at the proximal and distal ends of these creases, mirroring their vertical orientation.

Preformed implants can be used to augment the malar area, the dorsum of the nose, the chin, the tear-trough, and other areas. These implants can be customized as needed.

With any implantable material, complications can occur. Rubin and Yaremchuk described complications including bleeding, hematoma, infection, movement or extrusion of implant, malposition, and, rarely, undercorrection and overcorrection.^[5]

If an infection does occur, the implant must be removed, as the infecting bacteria cannot be eradicated from the ePTFE despite antibiotic treatment.

Most patients are pleased with the outcomes of ePTFE facial augmentation; however, if the need arises, the implant can be extracted and replaced. Gore-Tex implants have a long history of being well tolerated in the body as vascular grafts. Facial implants of ePTFE have a shorter history of use than vascular grafts, but the complication rate has been acceptable. Innovations in techniques and in the shape and form of the implants have reduced extrusion rates.

Modifications are continually being made to improve the results of soft tissue augmentation. For example, the diameter of the SoftForm lip implant has been increased. Advanta has a harder outer shell that covers a softer inner one, creating a softer feel.^[6] UltraSoft is 3 times softer than SoftForm. Neither SoftForm and UltraSoft are now available. Gore SAM discontinued the marketing of their products for plastic surgery in November 2006. Advanta is still available through Surgiform. A new ePTFE called FulFil is available from Evera. IT is a saline-filled ePTFE implant that is adjustable by filling it with saline.

Although more and longer-lasting varieties of injectable dermal fillers are available, ePTFE implants will continue to have their role in permanent augmentation.