Facial soft tissue fillers are an integral part of aesthetic medicine. The majority of clinical trials and reports in the literature suggesting facial plastic surgery are aimed at improving age-related appearance in older Caucasians. In Asian populations, the majority of facial plastic surgery is performed on young adults, and clinical guidelines for the use of soft-tissue fillers in Asian facial plastic surgery have not been reported. So what guidelines should cosmetic surgeons follow when dealing with Asians, who are different from Caucasians? A group of experts from Yonsei University and other institutions in Korea discussed this issue and made recommendations that were published in the journal Plastic and Reconstructive Surgery. Figure 1 Facial contouring after alteration Before injection (left) and 1 month after filler injection (right) Characteristics of fillers In this study, two injectable fillers, polymerized dense hyaluronic acid and calcium hydroxyapatite, were investigated. Viscosity and elasticity are the main factors affecting the application of fillers, and in general, the greater the viscosity of the filler, the deeper it is injected. Asian Faces Compared with Caucasians, Asian faces are wider and rounder, with a flatter mid-face than Westerners, a flat forehead, a smaller and wider nose, oval lips with no three-dimensionality, and a wider jawline without a protruding chin. Age characteristics: Asians have thicker and darker skin, the soft tissue and fat under the face is dense enough to maintain the facial contour for a longer period of time, so their skin sagging and wrinkles will appear later. Aesthetics: Asians mainly want to modify those facial features or contours that are not attractive. Revision of the T-zone is the most fundamental and major aspect of facial plastic surgery for Asians (see Figure 2). Fig. 2 T-zone before (left) and after (after) injectable filler in all areas of the T-zone Plastic surgery recommendations for the various facial zones Forehead: Enlargement of the forehead is the most important aspect for Asians to enhance the three-dimensionality of the forehead (see Fig. 3). When the forehead is fuller than in Caucasians, the need to continue to eliminate wrinkles is less of a problem, and the face looks younger (see Figure 4). Fig. 3 Before (left) and after (right) forehead filler Fig. 4 Forehead filler injection sites Clinical recommendations are to perform forehead filler at the same time as neurotoxin pretreatment. Anatomical recommendations: the amount of filler used should not be excessive, and filler injections should avoid the supraorbital artery, the superior talar artery, and the frontal branch of the superficial temporal artery. Temples: For young people, fillers should be harmonized with the forehead filler (see Figure 5); for older people, fillers in the lateral brow area are the main focus. Anatomically, it is recommended that the temporal artery and the frontal branch of the facial nerve be avoided and that the supraperiosteal level is the optimal injection point. Figure 5 Injection points for temple fillers Eye sockets: Fillers in the mid-face can improve the appearance of bags and hollows under the eyes, and are also recommended as the first step in a complete facial rejuvenation (see Figure 6). Anatomical recommendations: excessive fat should be raised before injectable fillers are performed in some cases. Expansion of the ocular recesses requires caution and is not recommended as it can easily result in irregularities, contamination or contamination, and more importantly, contamination of the facial arteries. Figure 6 Injection points for filler in the concave area of the eyes Central face: Asian faces are wide, short, and flat, so injectable fillers in the deeper part of the cheeks can increase the overall fullness of the central face and the face (see Figure 7) Figure 7 Cheeks before (left) and after (right) Anatomical recommendations: To create a three-dimensional hierarchy in the central face, it is important to reduce the volume of fat under the eyes, reduce the more prominent lines and folds of the nose and lips, and increase the curvature of the upper lip (Figure 8). The curvature of the upper side of the lip should be increased (Fig. 8). Fig. 8 Anterior medial cheek filler injection points Asian people do not like prominent cheekbones and prefer a rounded apple face. Fillers are used to give the cheekbones and cheekbones a smoother and more defined contour (Figures 9 and 10). Figure 9 Filler injection sites in the middle zygomatic area Figure 10 Filler injection sites in the outer zygomatic area Nose: Asians have a flatter nose with shorter nasal bones; the bridge of the nose is lower and the nasolabial folds are prominent. Filler injections are used to improve the bridge of the nose or to raise the tip of the nose (Figure 11). Fig. 11 Non-surgical rhinoplasty injection sites Because filler filling of the lips is not easily performed, the panel does not recommend routine treatment of the lips, but does recommend the use of additional filler nasal spines to add thickness to the lips in some cases. Anatomical recommendations: The nose has a high number of blood vessels supplying blood, and injections into blood vessels should be avoided, otherwise local ischemia, tissue necrosis or even blindness may result. Nasolabial fold and maxillary area: Nasolabial fold filling is not only to fill the deeper sulcus but also to increase the three-dimensionality of the maxilla and to support the collapsed midface (Figure 12). Figure 12 Injection points for nasolabial fold filling Anatomical recommendations: shallow injections in the face can easily injure the descending branches of the facial arteries; therefore, slow, deep injections are highly recommended. Chin and Jaw: The chin and jawbone are an integral part of the body (Figures 13 and 14). Some people prefer an inverted triangular chin, while others prefer a narrow, elongated chin, so it is important to communicate with your doctor in a timely manner to determine what kind of chin you want. Anatomical advice: avoid all kinds of tiny blood vessels at the tip of the chin when injecting, the injection site should not be too shallow, and overkill should be avoided, otherwise it will be unnatural. Soft tissue filling should also consider the front and back edges of the jaw, otherwise the smooth line of the jaw will be destroyed. The incidence of lumps after subcutaneous injection and the location of facial arteries and veins should also be considered. Figure 13 Chin filler injection point Figure 14 Jaw filler injection point Perioral area: Asian upper lip is thicker, the golden ratio of upper and lower lip is 1:1.2, a small amount of filler injected into the edge of the lip can form a clear outline of the lip, and a small amount of filler injected into the lip can increase the volume of the lip and achieve a satisfactory ratio of upper and lower lip (Figure 15). Figure 15 Lip filler injection points Young people only need to thicken the mid-lip and mid-central ridge whereas older people need to thicken the full lip and add volume to the full lip to improve wrinkles. The treatment of the marionette lines (Fig. 16) and the thin anterior sulcus of the lobes are contiguous and generally marionette lines are difficult to remove, in which case they can be layered with high to low viscosity fillers. Anatomical advice: the movement of the muscles around the lip dictates that calcium hydroxyapatite should not be used for lip fillers. Fig. 16 Puppet line filler injection site Hand area: The injection of the hand with fillers is intended to increase the visibility of the underlying bones, tendons and, in the case of veins, the same thinness as the dermis (Fig. 17). Highly viscous hyaluronic acid and calcium hydroxyapatite are both ideal filler injection sites located between the epidermis and superficial fascia. Anatomical advice: Hand injections can be painful and require anesthesia. Figure 17 Hand Fillers Injection Sites Restorative Intradermal Injectables: Large injections of small, bulk hyaluronic acid into the dermis can enhance the feeling of fullness and firmness of the skin, improving surface smoothness and elasticity and collagen synthesis. Nearly 75% of the panelists use hyaluronic acid for routine injections in the face and neck, and intradermal and subcutaneous injections are recommended. Prevention and management of complications All filler injections are associated with different complications such as redness, swelling and erythema. Non-inflammatory nodules usually occur when the filler injection site is too superficial or overcorrected. Use saline or lidocaine to destroy the nodules or dilute the filler to redistribute the filler; vascular injury is rare but the consequences of injury are serious, once it occurs, the treatment should be terminated immediately and appropriate remedial measures should be taken; injection combined with contamination is prone to produce inflammatory nodules. Due to the special characteristics of Asian faces and the specificity of aesthetic requirements, facial soft tissue filler requires special treatment. When performing multi-regional facial improvement, the first consideration is to fill in the middle of the face, restoring the volume of fat particles in the middle of the face can lift the cheeks and improve the appearance of the eye sockets, nasolabial folds, and the corners of the mouth. Fillers in the forehead, nose, and chin, or T-zone, can be used to give the Asian face a more three-dimensional and three-dimensional silhouette. The recommendations of this 13-member Asia-Pacific expert panel provide a clinical reference for physicians who wish to apply hyaluronic acid and calcium hydroxyapatite to Asian facial plastic surgery.