Introduction

The melomental folds (MMFs) are defined as the curvilinear folds running inferiorly from the oral commissure towards the mandible. They form the anatomical division between the lower lip and cheek, as well as the chin and cheek cosmetic units. A number of factors contribute to the formation of MMFs – chiefly loss of soft tissue volume and elasticity in the mid-face, bony atrophy of the mandible, and gravitational pull. The end result is downward descent of mid-facial tissue with festooning of the upper lip over the oral commissure and of the lower medial cheek over the lateral portion of the lower lip / chin subunit, thus forming the marionette-like appearance of the melomental crease.

The MMFs give a downturned appearance to the mouth, which may falsely convey the impression of anger or ‘sourness’. Impressions made within the first few fractions of a second of viewing a face have been found to have a lasting effect on interpersonal relationships. Similarly, subjects’ self-perception can be modified by their own facial expression. As such, many patients feel, correctly, that their MMFs cause them tangible life difficulty. Understandably, treatment of this troublesome area has long been desired. Historically, alternatives such as face or lip lifts yielded disappointingly high MMF recurrence rates, as have numerous resurfacing techniques including dermabrasion, chemical peels, and laser resurfacing. Botulinum toxin injection of the depressor anguli oris does provide some attenuation of the MMF, but oftentimes is not sufficient to fully efface these rhytides. It will be discussed in more detail later in the chapter as an excellent adjunct for MMF correction.

The advent of soft tissue fillers has revolutionized the treatment of this troublesome area. Fillers offer a minimally invasive, reliable treatment modality with an excellent safety profile and minimal post-procedure downtime. Additionally they allow for the possibility of easy titration and stepwise correction, if needed, to achieve the desired cosmetic effect. The ever-expanding library of soft tissue fillers allows for improved tailoring of the product to your patient’s needs.

Anesthesia

Minimizing the pain associated with any procedure is key to insuring patient satisfaction. As injections in the perioral area are frequently more painful than mid-facial areas owing to increased sensory innervation, anesthetic measures are more often necessary. While lidocaine-containing hyaluronic acid (HA) fillers (Juvéderm XC, Restylane-L, Prevelle Silk) or the mixture of calcium hydroxylapatite (Radiesse) with lidocaine significantly decrease the pain of injection, some patients may still benefit from additional pain control measures. In many, a measure as simple as pre-injection cryoanesthesia with ice may be sufficient. If more profound analgesia is judged necessary, the workhorse anesthetic methods for MMF augmentation are topical anesthetic agents and regional blockade of the mental nerve.

Topical anesthetic agents such as 5% lidocaine creams (LMX-5) or lidocaine / prilocaine mixtures (EMLA or Betacaine), while providing adequate anesthesia, require occlusion and application periods in excess of 30 minutes, which may limit their use in a busy clinical practice. A eutectic lidocaine / tetracaine peel (S-Caine peel) has been developed that can achieve anesthesia in as little as 20 minutes and has been found to be superior to EMLA applied under occlusion for 30 minutes. In the authors’ experience, Betacaine Plus ointment can provide adequate anesthesia within 10 minutes without the need for occlusion.

Bilateral mental nerve blocks may be used to achieve anesthesia of the lower facial unit. The mental foramen may be reliably located in the mid-pupillary line approximately 1 cm inferior to the gumline. An intraoral approach just below the second premolar provides a reliable way of executing the block without the pain of a percutaneous approach.

Basic principles for melomental fold correction

The correction of the MMF with soft tissue fillers requires proper selection of filler product in concert with appropriate injection technique and depth of placement. Only with the proper intersection of these three parameters may optimal results be achieved. Generally speaking, the MMFs are more difficult to correct than the melolabial folds, given the role of bony atrophy and significant lower facial volume loss in the pathogenesis of the former. As the deficit in question may be more profound than can be corrected by simply ‘filling a wrinkle’, linear threading or serial puncture techniques may prove inadequate to attenuate more advanced folds. Rebuilding structural support for the oral commissure and deeply set MMFs is best accomplished with techniques that place a larger amount of filler across a broader area, such as cross-hatching or fanning.

MMFs are best addressed with injection into the deep dermis. This in turn demands the use of sturdier filler such as a highly cross-linked HA product (Juvéderm Ultra Plus, Prevelle) or calcium hydroxylapatite (Radiesse). The fold should be injected from inferior to superior, attenuating the rhytide and building a buttress of support for the oral commissure. Additionally, injections should be oriented from medial to lateral as this will minimize the risk of traumatizing the facial vein, which runs just lateral to the MMF. For the most deeply set MMFs, vertical layering of fillers may be necessary to achieve the desired result. For example, if a deeply injected, cross-hatched, heavier weight filler is insufficient to attenuate the MMF, the addition of a more superficially placed, lighter weight filler can efface etched components to the fold.

Injection strategies for melomental fold correction

While ultimately a treatment plan must be individualized for a given patient, there are some broad generalizations that may be made. The Validated Melomental Fold Scoring System allows for division of MMFs into four classes based on severity, as summarized in Table 21.1. An excellent and thorough discussion of this classification may be found in the article by Carruthers et al in the Further reading section. This scoring system will be used to more concisely discuss treatment strategies for patients based on the severity of their MMFs.

Class I MMFs are the earliest and shallowest presentation of this rhytide. They unsurprisingly are the easiest to correct and may be treated easily with mid-dermal injection of an intermediate viscosity HA product (Restylane or Juvéderm Ultra) using a linear threading technique.

Class II folds are slightly deeper than their class I counterparts, but still will disappear upon stretching of the skin. These folds may require the use of a thicker product that consequently must be injected in the deep dermal plane. Should linear deposition of filler fail to efface these folds, a cross-hatching pattern of filler placement should be adopted. Figure 21.1 demonstrates the use of Radiesse in this area.

Figure 21.1 (A, preoperative; B, 1 week postoperative): grade II melomental folds. Injection of calcium hydroxylapatite (Radiesse) in a cross-hatched pattern was used for correction. Additional injection was performed to correct the pre-jowl sulcus.