Current Concepts in Lip Augmentation

Historically, a variety of tools have been used to alter one’s appearance for cultural or religious purposes or to conform to standards of beauty. As a defining feature of the face, the lips provide a unique opportunity for facial aesthetic enhancement. There has been a paradigm shift in medicine favoring preventative health and a desire to slow and even reverse the aging process.¹ Acknowledging that product technology, skill sets, and cultural ideals continually evolve, this article highlights perioral anatomy, explains aging of the lower face, and reviews techniques to achieve perioral rejuvenation through volume restoration and muscle control.

Perioral Anatomy

The layers of the lips include the epidermis, subcutaneous tissue, orbicularis oris muscle fibers, and mucosa. The upper lip extends from the base of the nose to the mucosa inferiorly and to the nasolabial folds laterally. The curvilinear lower lip extends from the mucosa to the mandible inferiorly and to the oral commissures laterally.² Circumferential at the vermilion-cutaneous junction, a raised area of pale skin known as the white roll accentuates the vermilion border and provides an important landmark during lip augmentation.³ At the upper lip, this elevation of the vermilion joins at a V-shaped depression centrally to form the Cupid’s bow. The cutaneous upper lip has 2 raised vertical pillars known as the philtral columns, which are formed from decussating fibers of the orbicularis oris muscle.² The resultant midline depression is the philtrum. These defining features of the upper lip are to be preserved during augmentation procedures (Figure 1).⁴

Figure 1. A diagram of the perioral anatomy.

The superior and inferior labial arteries, both branches of the facial artery, supply the upper and lower lip, respectively. The anastomotic arch of the superior labial artery is susceptible to injury from deep injection of the upper lip between the muscle layer and mucosa; therefore, caution must be exercised in this area.⁵ Injections into the vermilion and lower lip can be safely performed with less concern for vascular compromise. The vermilion derives its red color from the translucency of capillaries in the superficial papillae.² The capillary plexus at the papillae and rich sensory nerve network render the lip a highly vascular and sensitive structure.

Aging of the Lower Face

Subcutaneous fat atrophy, loss of elasticity, gravitational forces, and remodeling of the skeletal foundation all contribute to aging of the lower face. Starting as early as the third decade of life, intrinsic factors including hormonal changes and genetically determined processes produce alterations in skin quality and structure. Similarly, extrinsic aging through environmental influences, namely exposure to UV radiation and smoking, accelerate the loss of skin integrity.⁶

The decreased laxity of the skin in combination with repeated contraction of the orbicularis oris muscle results in perioral rhytides.⁷ For women in particular, vertically oriented perioral rhytides develop above the vermilion; terminal hair follicles, thicker skin, and a greater density of subcutaneous fat are presumptive protective factors for males.⁸ With time, the cutaneous portion of the upper lip lengthens and there is redistribution of volume with effacement of the upper lip vermilion.⁹ Additionally, the demarcation of the vermilion becomes blurred secondary to pallor, flattening of the philtral columns, and loss of projection of the Cupid’s bow.¹⁰

Downturning of the oral commissures is observed secondary to a combination of gravity, bone resorption, and soft tissue volume loss. Hyperactivity of the depressor anguli oris muscle exacerbates the mesolabial folds, producing marionette lines and a saddened expression.⁷ With ongoing volume loss and ligament laxity, tissue redistributes near the jaws and chin, giving rise to jowls. Similarly, perioral volume loss and descent of the malar fat-pad deepen the nasolabial folds in the aging midface.⁶

The main objective of perioral rejuvenation is to reinstate a harmonious refreshed look to the lower face; however, aesthetic analysis should occur within the context of the face as a whole, as the lips should complement the surrounding perioral cosmetic unit and overall skeletal foundation of the face. To accomplish this goal, the dermatologist’s armamentarium contains a broad variety of approaches including restriction of muscle movement, volume restoration, and surface contouring.