Non-hyaluronic acid fillers for facial augmentation

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CHAPTER 75 Non-hyaluronic acid fillers for facial augmentation

Douglas S. Steinbrech, Oren M. Tepper

History

The concept of soft tissue fillers dates back to as early as the 19th century with Nueber’s description of the use of autologous fat for tissue augmentation. Soon thereafter, permanent synthetic fillers were applied for cosmetic purposes. Paraffin, for example, was injected into the face at the start of the 20th century, but had only limited success due to the risk of granuloma formation. Other permanent injectables such as silicone have been used “off-label” for improved cosmesis, but have experienced a variable and controversial clinical course.

Given the risk of irreversible complications with permanent injectable substances, the medical community sought to develop non-permanent soft tissue filling agents. The first temporary soft tissue filler to be introduced to the market was collagen in 1977, but numerous other substances have since been developed. Today, soft tissue augmentation with temporary fillers represents one of the most popular procedures performed in medicine.

Soft tissue fillers can help achieve a more youthful appearance by addressing the effects of tissue atrophy, or by augmenting areas that help define an attractive face. Soft tissue fillers are generally used to treat nasolabial folds, glabellar wrinkles, marionette lines, perioral wrinkles, and the lips. Other age-related changes of the face such as ptosis or inferior skin quality, however, cannot be successfully treated with soft tissue fillers. As patients continue to seek minimally-invasive procedures to address these age-related changes, it can be expected that soft tissue fillers will continue to play an important role in physician practices for many years to come.

Classification of fillers

Various types of injectable substances are currently available to restore a youthful appearance. Compounds manufactured from natural tissue may be thought of as biologic, and can be classified based on their origin from either a human (allogeneic) or animal source (xenogeneic). Synthetic, or alloplastic, materials represent man-made compounds used to augment the face for facial rejuvenation. Lastly, autologous tissue that is harvested from elsewhere in the body and used for tissue augmentation may be classified as syngeneic products. An overview of this classification scheme can be found in Table 75.1. The following chapter highlights xenogeneic, allogeneic, and alloplastic soft tissue fillers (Table 75.2).

Table 75.1 Dermal filler classification

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Table 75.2 Side effects associated with soft tissue fillers

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Xenogeneic

Bovine and porcine collagen

The use of collagen adhesive can be traced back as far as the Egyptians 4000 years ago. The word collagen is derived from the Greek word for glue, kolla. Collagen, or “glue producer”, refers to the early process of boiling skin and tendons of animals to obtain glue. Injectable bovine collagen was introduced to the market in 1981 and became the first commercially available filler to be approved by the FDA for soft tissue augmentation. Today, collagen has become one of the most commonly utilized injectable agents, with an estimated use of over 200,000 injections per year.

Zyderm represents the first form of bovine collagen to be developed. Newer generation bovine products have been established which include Zyplast and Zyderm II (Inamed, Santa Barbara, CA). Zyplast consists of cross-linked fibers, while Zyderm II consists of a more viscous form of Zyderm. Zyderm is primarily injected into the superficial dermis, and is recommended for correction of fine wrinkles at the crow’s feet, lip, and marionette lines. In comparison, Zyplast is injected at mid-dermal layer, and thus should be used to correct deformities such as deep nasolabial folds. Porcine collagen products include Permacol (Tissue Science Labs, UK), Fibroquel (Aspid, Mexico), and Evolence (ColBar LifeScience, Israel).

Because an estimated 3–5% of the population has a pre-existing allergy to collagen, it is essential to perform a skin test 4 and 2 weeks prior to use. In patients with a history of an uncomplicated collagen injection of more than 1 year prior, a single test dose is also recommended.

Allogeneic

Human collagen

As animal-based collagen products continued to gain popularity, scientists aimed to develop human-based collagen products in order to alleviate concerns of allergenicity. The first of the human collagens to be introduced to the market included Dermolagen (Collagen Matrix Technologies, Boca Raton, FL) and Autologen (Autogenesis Technologies, Acton, MA). The production of Autologen involves harvest of autologous skin and subsequent extraction of collagen from decellularized human dermis. In comparison, Dermolagen provided an advantage of processing collagen from cadaveric skin.

In 2003, the family of Cosmoderm products (Inamed, Santa Barbara, CA) were introduced to the market and approved by the FDA. Cosmoderm I (collagen concentration of 3.5%) and Cosmoderm II (collagen concentration of 6.5%) are currently used to treat fine-to-moderate wrinkles. Cosmoplast is a more robust formulation for deeper lines and folds. These human-based products provide the advantage of not requiring a test dose for skin sensitivity. Other human collagen products that are available for use include cadaver-based products: Fascian (Fascia Biosystems, Beverly Hills, CA) from cadaveric fascia and Cymetra (LifeCell Corp, Branchburg, NJ) which is a particulate form of alloderm.

Cross species

More on this topic may be found in Chapter 74 on hyaluronic acid fillers.

Alloplastic

Hydroxylapatite (Radiesse)

A unique form of soft tissue fillers that was recently introduced to the market is synthetic calcium hydroxylapatite. The most well known product is Radiesse, formally known as Radiance FN (Bioform Medical, San Mateo, CA), which consists of calcium hydroxylapatite (30%) and an aqueous carrier gel (70%). At present, Radiesse was initially approved by the FDA for filling of oromaxillofacial defects, soft tissue marking, and laryngeal augmentation. In 2006, FDA approval for Radiesse was extended to the treatment of nasolabial folds and lipoatrophy.

Many clinicians believe that Radiesse may offer exhibit greater longevity relative to other temporary fillers, lasting 12–18 months. One potential explanation for this observation may be its mechanism of action. Following injection of Radiesse, the carrier gel is gradually absorbed and new collagen formation occurs around the calcium hydroxylapatite microspheres. Studies to date demonstrate calcium hydroxylapatite to be biocompatible and non-antigenic, and thus sensitivity testing is not necessary prior to delivery.

Poly-L-lactic acid (Sculptra)

Sculptra (Sanofi-Aventis, Bridgewater, NJ) consists of poly-L-lactic acid (PLLA) and was approved by the FDA in 2004 for the treatment of facial lipoatrophy secondary to HIV-associated medications. Worldwide, Sculptra is utilized for aesthetic indications as well. Sculptra is primarily used to fill deep folds or areas of significant atrophy, and therefore should be delivered in the deep dermis or subcutaneous space. Side effects of Sculptra include delayed appearance of subdermal bumps, but some believe that this risk is significantly decreased by the delivery of Sculptra in a more dilute form.

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