Complications of Permanent Fillers

Introduction

Injectable facial fillers have become a cornerstone of aesthetic medicine over the past two decades. Although soft tissue augmentation using industrial-grade silicones can be traced to early last century, widespread adoption of injectable fillers began in the 1970s with the advent of bovine collagen. Since the 1990s, with the US Food and Drug Administration (FDA) approval of hyaluronic acid (HA) temporary fillers, soft tissue augmentation for filling lines and volumizing or recontouring the face has surged to become the second most popular nonsurgical aesthetic procedure in the United States, with more than 2.7 million procedures performed in 2019. Based on the axiom that an aged facial appearance is due in some part to dermal, subcutaneous, and osseous atrophy that naturally occurs over time, injectable facial fillers offer the ability to replace lost volume and restore youthful proportions, providing a foundation for facial rejuvenation.

As with certain other nonsurgical aesthetic modalities, facial filling is a product-driven procedure. Beyond an adroit injection technique, judicious use of the appropriate product in the proper location is a prerequisite to success. To know the art of injection, one must know the products, and the products vary significantly. In 2010, more than 200 fillers from over 60 manufacturers worldwide were available for tissue augmentation. Although some share characteristics that may predict a similar clinical response or comparable side effect profile, inappropriate substitution with a dissimilar product, particularly by a novice injector or non-core aesthetic provider, invites complications and ultimately patient dissatisfaction and compromises patient safety.

Although there is no universally accepted classification for soft tissue fillers, they can be classified based on their origin—natural animal, synthetic, or natural synthetic. Fillers may be further divided based on their longevity: temporary, semipermanent, or permanent. Temporary fillers are typically biologically derived products that are eventually broken down in vivo after a period of a few months to a few years. This category includes collagens and HAs, the most predominant fillers worldwide. In contrast, permanent fillers comprise mostly synthetic materials that have an in vivo, biodynamic mechanism of action, causing collagen deposition via fibroplasia. They are composed of nonabsorbable, permanent material. For this reason, permanent fillers are better at facial volumizing and deep structural augmentation than at “line filling,” which is better accomplished with temporary fillers. Note that “permanence” refers to a lack of degradation of the in vivo material over time rather than to a “permanent” cosmetic result. Once placed, permanent fillers remain in the skin and subcutaneous tissues indefinitely. Permanent aesthetic results are seldom possible owing to continued tissue volume loss, bone resorption, and other factors associated with the aging face. Nevertheless, duration of correction is more extensive than with temporary fillers. As such, permanent fillers are less “forgiving.” Experience and precise technique are required to achieve favorable outcomes.

Liquid Injectable Silicone

Silicone is one of the oldest and longest-lasting injectable fillers. Liquid injectable silicone (LIS) received FDA approval in 1959 for intraocular use as a retinal stabilizing agent during vitreous surgery. Its off-label use as a filler is controversial due to potential long-term complications. The FDA-approved medical-grade silicone oils that are recommended for cosmetic use including Silkon-1000 (Alcon, Fort Worth, TX) and Adatosil-5000 (Bausch & Lomb, Rochester, NY). Although injectable silicone has been effectively used for more than 50 years, its use remains controversial owing to the historical widespread reports of complications, most of which are confounded with unknown or impure products labeled as “silicone” and purified silicones injected by improper techniques. When critically evaluating silicone, the distinction must be made between modern products intended for injection (LIS) in contrast to adulterated or impure products lumped under the “silicone” label that is manufactured outside the United States. LIS demonstrates a unique aptness for the correction of specific cutaneous and subcutaneous atrophies owing to its versatility, permanence, excellent cost–benefit profile, and natural texture in vivo. Furthermore, evidence continues to mount demonstrating that modern silicone oils approved by the FDA for injection into the human body may be successfully used off-label when injected according to strict protocol, which includes using the microdroplet serial puncture technique (defined as the injection of ≤ 0.1 mL at 2 to 10 mm intervals subdermally with a small diameter needle) with limited quantities per session and adequately spaced treatment sessions. In contrast, adulterated and impure silicone products, even when labeled “medical grade,” are rife with complications.

Polyalkylimide Gel

Bio-Alcamid (Polymekon, Italy) was first launched in 2000 and has been used in more than 20 countries. It does not require skin allergy testing prior to use ( ). Its use was originally as an “endoprosthesis” for the treatment of pectus excavatum and postoperative defects as well as aesthetic use in the lips, cheeks, and nasolabial folds ( Fig. 36.1 ). It contains a nonbiodegradable, nontoxic, nonimmunogenic synthetic polyalkylimide cross-linked polymer suspended in water. Although it is approved in Europe, it is not approved by the FDA. Bio-Alcamid contains a ratio of 3% alkylamide polymer to 97% sterile water. The product is a gel that is injected as a large bolus subcutaneously. After injection, the polyalkylimide gel is completely covered by a thin collagen capsule (0.02 mm) that isolates it from host tissues, making it a type of endogenous prosthesis ( ). It has been successful and safe in treating human immunodeficiency virus (HIV)–associated facial lipoatrophy and showed persistent correction at 18 months. There have been reported cases of product migration and infection that occurred 12 months after injection ( ).