INTRODUCTION
Excess submental fat, known in colloquial terms as a “double chin,” is a common cosmetic concern among patients today. There are currently many new non-invasive and minimally invasive techniques for addressing this traditionally difficult to target anatomic area. In a recent 2015 American Society for Dermatologic Surgery (ASDS) survey, excess submental fat was as bothersome to patients as sagging skin and wrinkles around the eyes.1 The etiology of excess submental fat can be related to the aging process as skin laxity increases and the submental fat pad deep to the platysma can prolapse inferiorly. Also, as patient’s gain weight, their submental fat compartments can enlarge and reduce the acuteness of the cervicomental angle. This anatomic site is very difficult to treat through traditional means of diet and exercise. Historically, the sole approach to improving this area of interest was submental liposuction, with or without a surgical neck tightening procedure. However, for medical reasons, including uncontrolled hypertension, significant tobacco use, or anti-coagulant therapy, many patients cannot undergo these surgical procedures.2 Herein, new non-invasive, minimally invasive, and surgical techniques for fat removal and skin tightening of the submental area will be reviewed. The techniques presented are: (1) cryolipolysis, (2) chemical lipolysis, (3) percutaneous thermal techniques, and (4) surgical liposuction.
Anatomy
The first objective is to define submental fullness, ie, “double chin” and the surrounding anatomic considerations. Patients with submental fullness present with a blunted cervicomental angle, often greater than 120o and a loss of the contour of the jawline and angle of the mandible. These characteristics of submental fullness can be due to other anatomic concerns such as a low hyoid position or enlarged submandibular glands, but the ideal candidate for the procedures reviewed will have hypertrophy of the pre-platysmal fat pad. The pre-platysmal fat pad is superficial to the platysma muscle (Figure 1) and is an easy target for the percutaneous techniques described. While there are no clinically significant vessels or nerves superficial to the platysma, the marginal branch of the facial nerve should be considered when addressing submental fullness. It runs within the fascia of the submandibular gland immediately deep to the platysma muscle and it is usually 1-2 cm inferior to the ramus of the mandible, but it can be found as far as 4 cm inferior to the mandibular ramus.3 Once anterior to the intersection of the facial artery and inferior margin of the mandible, the marginal mandibular nerve is described as being above the inferior margin of the mandible and out of harm’s way when addressing submental fat.4
Treatment Options
CoolsculptingTM The first therapeutic intervention that is discussed is cryolipolysis. This technique is available through Zeltiq’s CoolsculptingTM using the CoolMiniTM applicator handpiece. This non-invasive technique utilizes adipose tissue’s increased sensitivity to cold to selectively induce apoptosis by maintaining the target preplatysmal fat at -10 oC for 45 minutes. Most patients undergo 1-2 treatments and the resulting apoptosis of fat cells has been shown to decrease superficial fat thickness treated by 2 mm with 77% of patients reporting a noticeable improvement in submental appearance.5 The FDA approved the cryolipolysis technology in 2010 for ank fat; the CoolMiniTM applicator was approved in 2015. Patients’ initially note a “butter stick” appearance of the submental tissue following treatment (Figure 2), when the applicator is removed, but this resolves within a few minutes and the final results can improve the cervicomental angle over
