BACKGROUND
The use of injectable fillers for the enhancement of facial aesthetics is among the most frequent nonsurgical cosmetic procedure performed in the U.S., second only to the use of injectable neuromodulators to relax the dynamic lines and wrinkles of the brow and eye area.1 Lip shape and fullness plays an integral role in the overall composition of facial aesthetics. As a primary component of outward appearance, facial aesthetics are intrinsically linked to self-perception of attractiveness, self-esteem, and social confidence.2,3 Lip shape also communicates emotion, even while the face is at rest; therefore, lips and perioral attributes have a significant role in the facial aesthetics equation, similar to the eyes and brow.4,5
The corrective needs of a patient can range from subtle enhancement of an already adequate shape and volume to a more comprehensive recontouring, including correction of perioral rhytides.6,7 Because the lip and perioral region experience regular dynamic movement, adding filler to enhance shape while still maintaining a natural appearance (during movement and at rest) is technically challenging. The lip and perioral region are also densely vascularized and vulnerable to injection site reactions, such as edema and bruising.8 A comprehensive understanding of the anatomical features and appropriate injection site techniques is important foundational information for an injector. Likewise, the choice of filler material is equally important because it facilitates the success of the injection techniques used; and therefore, promotes a safe, effective, natural-looking outcome, as well as patient comfort. Effective fillers for lip and perioral rhytid correction are the small-particle hyaluronic acid (HA) gels. The particle size and rheological properties of these gels are well-suited to the constraints of fine gauge needles, and the superficial injection techniques required for lip enhancement.9-12 The small-particle HA 20 mg/mL with lidocaine 0.3% (SP-HAL, Restylane® Silk; Galderma Laboratories, Fort Worth, Texas) is the first FDA approved (2014) filler formulated with lidocaine that is indicated for submucosal implantation for lip augmentation and dermal implantation for correction of perioral wrinkles in patients over the age of 21.13,14 The purpose of this manuscript is to provide guidelines regarding ideal injection techniques for different corrective needs using the SP-HAL Restylane Silk filler.
Lip and Perioral Anatomy
Whether the goal is to enhance youthful lips or restore shape and volume to aging lips, an understanding of the relevant anatomy and the ability to employ a suitable corrective need is foundational. The evaluation process for correcting lip shape and volume ideally should consider lip proportion in context with the whole face. Facial proportions can be divided into thirds as upper, middle, and lower face. The lowest third of the face, is further divisible into thirds, as upper lip, lower lip and chin, and there are general metrics to consider for achieving the most aesthetically pleasing proportions (Figure 1).
