Introduction to “Fillers: The State of the Science—A Multispecialty Evidence-Based Initiative”

Facial filler injections have gained tremendous popularity in the more than 20 years they have been available in the United States, due to their instant results, robust safety profile, and minimal patient downtime.1 Hyaluronic acid (HA) gel fillers have become the prevalent facial fillers at present, largely due to their ease of injection and reversibility. Despite positive overall outcomes, challenges remain and continue to grow as the HA filler industry becomes more complex. The widening variety of HA fillers can confuse both novice and experienced practitioners, especially in the setting of additional facial procedures. As such, achieving optimal placement for desired results is increasingly difficult, and vascular and nonvascular complications often deter treatment of critical facial aesthetic subunits.2,3 The articles presented in this issue are designed to address the increasing complexity of the HA filler practice and to aid patient outcomes. The clinical applications for HA fillers have greatly expanded since their inception in the nasolabial fold.4 Their U.S. Food and Drug Administration–approved use now also includes the malar areas, lips, temporal regions, jaw line, chin, and hands. Off-label use covers almost any facial area. Although volume replenishment and wrinkle treatment are relatively straightforward, using HA fillers for facial structural support is more challenging.5 There is no consensus on the best approach for the latter, though some scholars suggest osteocutaneous ligament injection.6 Concurrently, there has been an expanding portfolio of HA fillers approved by the Food and Drug Administration that is characterized by different manufacturing technologies and rheological properties. These include the Restylane series, the Juvederm series, the Resilient Hyaluronic Acid series, the Evolysse series, and Belotero, among others. With the diverse options available, practitioners may find it challenging to select the appropriate filler for a given clinical scenario. For example, fillers with different G′ values are known to be suitable for various facial areas and layers, but the choice of the HA filler must be based on the entire array of rheological properties, as the G′ value does not capture all the qualities and specificities of a product. Other characteristics, such as hydrophilicity, cohesivity, flexibility, migration, and inflammation capacities, can affect both immediate and long-term treatment results. These aspects are not fully understood and have been scarcely discussed in the literature due to insufficient rigorous scientific data, leading to potential complications by unseasoned practitioners. As a result, long-term complications have become a subject of recent discussion, particularly “filler fatigue.” Although no publications were found on this subject in our search, the term appears on multiple social media platforms and websites. “Filler fatigue” refers to the puffy and potentially more aged appearance of the face after filler placement. Causes may include overinjection, HA filler hydrophilicity, filler migration, tissue inflammation, and chronic, repeated HA filler injections. The skin may stretch and lose elasticity, particularly after hyaluronidase treatment.7 It is uncertain whether all instances of “filler fatigue” are accurately diagnosed, as some cases that seem “overfilled” may present similar conditions. Experienced injectors, including some of the authors highlighted here, are now being sought out to treat patients with overfilled or “filler-fatigued” faces, a trend that was not present 5 years ago. This phenomenon may suggest 1 of 2 possibilities: (1) patients may now appreciate the importance of naturalness for their facial aesthetic treatments; or (2) the extended use of HA fillers (for more than 10 y) is finally beginning to reveal its long-term adverse outcomes. On this note, we expect that more instances of “filler fatigue” will show up in the near future. We are pleased here to have 3 esteemed groups of authors present their perspectives on important current principles of HA fillers. Soares et al.8 provide an in-depth, cutting-edge analysis of the rheological properties of HA fillers, including G′, G″, and tan, among others, all of which are supported by elegant data and relevant clinical implications. Malphrus et al.9 share a broader clinical perspective on the up-to-date clinical applications of HA fillers, emphasizing the importance of multimodal, synergistic approaches to enhance patients’ anatomical features in a region-by-region and panfacial manner. Finally, Claytor et al.10 discuss their recommendations for improving treatment quality while preventing acute and long-term complications. Together, the articles presented here address the most current pertinent issues related to enhancing facial appearance with HA fillers. We believe that these 3 articles will help practitioners better understand HA fillers, their correct application, and how to minimize complications. Although factors such as hydrophilicity, migration patterns, and inflammation necessitate further rigorous investigation, it is essential to restrict the excessive and indiscriminate use of HA fillers by both patients and practitioners. Practitioners should learn to say “no” to filler addiction, and should understand and address “perception distortion,” as improper injections can damage not only patients but the entire aesthetic medicine field. In reality, this type of “tough love” and honesty in practice, although perhaps uncomfortable at first, will help practitioners gain more patients’ trust and therefore retain more loyal patients, which in turn leads to a more fulfilling doctor–patient relationship and better patient outcomes. Our goal, after all, is to enhance beauty and quality of life for patients in a safe manner. The techniques presented in this supplement to Plastic and Reconstructive Surgery do not necessarily represent best practices or endorsed techniques of the guest editors, editor-in-chief, editorial board, the American Society of Plastic Surgeons (ASPS), or Wolters Kluwer Health. Publication of supplements does not constitute product or sponsor endorsement by this Journal or the ASPS. This supplement was made possible by a sponsorship from Galderma (Galderma Pharma, S.A., Switzerland). Some current and past advisors, investigators, and consultants to Galderma did serve among the guest editors and authors on the articles herein, as allowed by the ASPS Supplement Publication Policy; all authors are listed on the articles as authors or acknowledged contributors, as Plastic and Reconstructive Surgery does not support ghostwriting. As with all Plastic and Reconstructive Surgery articles, financial disclosure statements are provided for each article, and with all supplements, they are intentionally and redundantly included as an appendix, for your convenience. None of the materials contained in this supplement are considered to be practice guidelines or best medicine protocols, but are merely the authors’ collective experience and expertise in the prescribed area. These articles have been rigorously peer-reviewed and revised before acceptance. We thank all of the authors who took time out of their busy careers to prepare these outstanding papers. We must also thank the group of plastic and reconstructive surgeons, dermatologists, and affiliated specialists who served as expert, unbiased, and efficient peer reviewers. These women and men worked on important topics and remained proficient, meticulous, and dependable. This supplement would not have been possible without them. We greatly appreciate the contributions and thorough explanations presented here and the authors’ perspectives on these important topics. Although the viewpoints presented may not encompass the entire scope of HA filler behavior, we believe these summaries hold significant value for the plastic surgery community and beyond. We have made diligent efforts to involve multiple core aesthetic specialties in this initiative to reflect broad and diverse perspectives. We hope that the readers will benefit from this comprehensive effort and that we will be able to provide future perspectives in a consistent and robust manner to continue optimizing outcomes in aesthetic medicine. DISCLOSURE Dr. Yu has no financial interests or conflicts of interest to disclose. Dr. Percec is a consultant for Allergan, Galderma, and Evolus. This work was supported by funding from Galderma (Galderma Pharma, S.A., Switzerland).