Dermatological Reviews最新文献

The use of hyaluronic acid (HA) fillers has become increasingly popular in the cosmetic industry due to their efficacy and versatility. Common types of HA fillers include Restylane, Juvéderm, and Bolotero. Other various options available for HA fillers include the resilient HA fillers (RHA) collection, Revanesse versa, and Prevelle silk. The fillers can be used singularly or in combination to achieve a desired cosmetic outcome. The RHA collection line is the first FDA approved filler used to treat dynamic facial lines using a less rigid formula than earlier HA fillers and by uniquely adapting to facial movement, stretching, and repeated facial compression. Revanesse versa filler is designed to effectively address moderate to severe facial wrinkles, including nasolabial folds, with a focus on providing lasting results even after the HA filler has been absorbed. Other HA fillers such as Prevelle silk, Hydrelle, and Puragen contain 0.3% lidocaine for more tolerable treatment for moderate to severe facial lines. Examples of combination fillers include HA/botulinum toxin, HA/calcium hydroxyapatite (CaHA), and HA/poly-l-lactic acid. To facilitate the administration of injections, HA fillers can also be mixed with agents such as lidocaine, lidocaine and epinephrine, normal saline, and sterile water to decrease viscosity. Furthermore, the use of CaHA in conjunction with microfocused ultrasound with visualization (MFU-V) has shown to enhance skin tightness and neocollagenesis. Other applications of HA include utilization of its bacteriostatic effects to coat biomedical devices, as a material for bioink and tissue-engineering, and to create novel formulations to further personalize cosmetic goals.

Soft tissue fillers have evolved since the days of bovine collagen. Currently, there are at least 20 different biodegradable soft tissue fillers in the market. The rapidly evolving technology behind these products changed the practice of esthetic medicine and expanded the cosmetic marketplace by attracting patients interested in affordable, minimally invasive procedures. In this series, we aim to review the most pertinent advances in soft tissue filler technology and their implications for clinical practice.

The first commercial fillers to gain Food and Drug Administration (FDA) approval were implantable purified bovine collagen products developed by Allergan in the early 1980s (Zyderm™, Zyplast™). These products required an intradermal skin test before injection due to the risk of hypersensitivity reactions to the bovine-derived peptides.¹ They also suffered from high manufacturing costs and short-lived clinical results.² The first-generation bovine collagen fillers are no longer available in the market, but several products were subsequently developed and remain in the market today in solution with polymethylmethacrylate (PMMA) such as Bellafill™ (Suneva Medical).

The advent of Restylane™ (Galderma) in 2003 heralded a new era for soft tissue augmentation. Restylane™ was the first filler based on cross-linking of hyaluronic acid (HA), a naturally occurring, protein-free glycosaminoglycan present in the dermis. HA retains water in the extracellular matrix of the dermis by forming a backbone for the binding of large polymer complexes with negative charges.³ Cross-linking inhibits the enzymatic breakdown of HA products in fillers and allows for much longer duration of clinical efficacy.⁴ Since Restylane was approved, many other HA fillers have been introduced to the market with a variety of different properties aimed at specific indications from nasolabial fold volumization to jawline contouring.

The unique cross-linking of each HA filler confers specific physical properties, which dictate the indicated uses for the product. In physics, rheology is the study of the deformation and flow of liquids. In the context of esthetic medicine, rheology refers to the study of soft tissue filler properties affecting their clinical performance. To choose the best filler for a case, the esthetic physician should consider the local physical forces including lateral sheering forces and vertical compression that will be applied to the filler. The elasticity (G′) of a filler describes its ability to resist lateral sheering forces and restore its original shape after forces are applied. The viscosity (G″) of a filler measures its inability to restore its original shape after forces are applied. The hardness (G*) describes the total energy needed to deform the filler.⁵ The cohesivity of a filler reflects its ability to resist dis

Dermal fillers are often utilized to enhance facial features as well as correct signs of aging on the face. Common side effects seen with dermal fillers are injection site erythema, edema, and secondary infection. Uncommon yet severe effects of filler injection result from vascular occlusion, causing skin necrosis, blindness, or even stroke. Vision loss typically occurs immediately after injection. Partial vision loss is associated with better prognosis. In case of visual compromise, an ocular massage and reduction of ocular pressure should be initiated immediately. The instruments used as well as the pressure and volume of the injection can contribute to unwanted complications. Anti-thrombolytics, including hyaluronidase for hyaluronic acid injection, may offer some benefit in the case of vascular occlusion. Aesthetic providers must have thorough knowledge of facial anatomy and proper injection technique to mitigate the risk of these dreaded adverse events.

The advancement of dermal fillers has progressed from animal collagen extraction to a spectrum of recombinant DNA, nanotechnology, and biostimulation. Consumers now have a variety of fillers to choose from, including organic fillers composed of hyaluronic acid and calcium hydroxyapatite, as well as synthetic fillers made from poly-l-lactic acid and polymethylmethacrylate. This piece serves to add to the open dialogue discussing the prognosis, prospects, and potential pitfalls of dermal fillers. Expansion of product indications and technical alterations are currently changing the dermal fillers' landscape. The potential for new approaches to side effect mitigation or adjunct pigment modification is still exploratory. Furthermore, with social implications increasingly coming into frame, healthcare providers and companies seem geared toward developing effective, safe, and equitable products while maintaining a process of rigorous review and quality control processes. As such, future developments of this medical tool appear promising; fillers seem poised to imbue a role as dynamic as the tissues they were conceived to restore.