Skin laxity is a very wide concept and it is related not only with skin quality (collagen and elastin fibers) but also muscle, bone and fat volume and also quality of superficial fascia. Clinically laxity is normally translated as sagginess without wrinkles associated to that. There are many studies that evaluated the effects of microfocused ultrasound with visualization (MFU-V) in combination with diluted calcium hydroxylapatite (CaHA) for treating laxity.

Most of the studies published showed that combining MFU-V with 1:1 diluted CaHA is effective for improving the appearance of laxity. Microfocused ultrasound with visualization (MFU-V) delivered by the Ulthera System (Ulthera, Inc.) is a proven technique for inducing neocollagenesis and subsequent skin tightening and is approved by the United States Food and Drug Administration and in Europe to non-invasively lift the eyebrow, submental and neck tissue, and improve lines and wrinkles of the décolletage. A number of studies have demonstrated its effectiveness for tightening the skin of the neck and décolletage with benefits including less skin sagging, fewer lines and wrinkles, and smoother skin texture (Fabi & Goldman, 2014; Baumann & Zelickson, 2016; Fabi et al, 2013; Fabi et al, 2015; Werschler & Werschler, 2016).

Research has discovered that the collagen-stimulating properties of Radiesse (Merz North America) can also be harnessed for skin-tightening procedures by hyper-diluting the product with either lidocaine or saline (Yutskovskaya et al, 2014). The use of this technique alone in the skin of the neck and décolletage has recently been shown to stimulate the synthesis of collagen and elastin, and increase neovascularization, and was associated with an increase in dermal thickness and improved skin mechanical properties including elasticity and pliability (Yutskovskaya & Kogan, 2017).

Both MFU-V and CaHA have individually demonstrated efficacy for skin tightening and improving skin quality in the neck and décolletage as well as other areas. With the availability of botulinum toxins and dermal fillers to smooth lines and wrinkles and restore volume to the face, imperfections in the neck, décolletage and other body areas often stand out in stark contrast to reveal a person’s age and are a significant aesthetic concern for many people. These areas are also often neglected in terms of skincare and sun protection yet are just as prone to the effects of UV damage as the skin on the face. The décolletage in particular receives a lot of sun exposure and is thinner than the skin on the arms and the legs, making it extremely vulnerable to UV damage. In women, the décolletage is also subject to constant physical stresses from the weight and movement of the breasts even while sleeping, contributing to the worsening of the deep, vertical cleavage wrinkles that appear as the skin becomes older and thinner. As a result of hormonal changes relating to the menopause and estrogen deficiency, women in their 40s and 50s are more prone to aging in this area. These changes result in an accelerated breakdown of collagen and elastin, leading to skin thinning and laxity, and worsening lines and wrinkles. The results of Casabona et al, 2017 retrospective study confirm that combination treatment with MFU-V followed by CaHA is effective for tightening the skin of the neck and the décolletage in men and women. Mean neck and décolletage wrinkle severity scores improved by at least 1 grade compared with baseline after only one treatment session whichever grading scale was used. Both treatments have previously demonstrated efficacy for neck and décolletage (Fabi et al, 2013; Fabi et al, 2015; Yutskovskaya et al, 2017).

Combining MFU-V and CaHA procedures is intuitive given that both stimulate neocollagenesis in the treatment area. MFU-V uses dual function transducers to deliver microfocused ultrasound energy at pre-selected depths below the skin’s surface at the same time as providing high-resolution ultrasound imaging of the skin layers to ensure the precision of energy delivery. Absorption of the ultrasound energy causes intermolecular vibration and heat production to temperatures of around 65°C, causing collagen denaturation and initiating collagen synthesis, without injuring the skin’s surface. Real-time visualization allows physicians to avoid anatomical features such as blood vessels and nerves. Following injection of CaHA, the CaHA microspheres act as a support for new tissue formation, activating fibroblasts with subsequent collagen and elastin production (Yutskovskaya et al, 2014; Marmur et al, 2004; Berlin et al, 2008). These collagen-stimulating properties of CaHA can be used for skin-tightening procedures by diluting the product with either lidocaine or saline (1:1 rate). The rationale for combining MFU-V and CaHA in the same treatment area is for an enhanced level of neocollagenesis, above that which can be achieved with either procedure alone, with greater skin-tightening and a longer duration of effect. Current consensus is that MFU-V should be performed first, but can be followed immediately by CaHA injection as in the current study (Fabi et al, 2016a).

Patient-reported outcome data are particularly relevant for aesthetic procedures because patients’ perception of treatment results is subjective. Overall, 93% of subjects were very satisfied or satisfied with the improvement in their neckline appearance and 94% of subjects in the appearance of their décolletage. This rate of patient satisfaction compares very favorably with 90-day results from studies in which MFU-V or CaHA were used to treat the neck or the décolletage individually (Oni et al, 2014; Fabi & Goldman, 2014; Baumann & Zelickson, 2016; Werschler & Werschler, 2016; Yutskovskaya et al, 2017; Fabi et al, 2013; Fabi et al, 2015), albeit with different patient questionnaires and different study inclusion criteria. Careful selection of patients is important as the aging neck and décolletage can be characterized by many different changes including skin dyspigmentation, laxity, rhytides, loss of the mandibular contour, accumulation of submental fat, volume loss and prominence of the platysmal bands, and not all are appropriate for treatment with MFU-V and CaHA. For example, in a prospective study of 93 patients who underwent MFU-V for improving skin laxity and tightening in the lower face, the relationship between treatment outcomes and body mass index was also examined (Oni et al, 2014). Overall improvement in skin laxity was noted in 63.6% of evaluated patients, but no change was detected in 54.5% of patients whose BMI exceeded 30 kg/m² compared with 12.2% of patients whose BMI was &le 30 kg/m². The combination of MFU-V and CaHA was well tolerated. Adverse events were limited to mild pain and transient bruising, similar to adverse events observed in skin-tightening studies in which the two procedures have been used individually. Both treatments have previously been shown to be safe in all Fitzpatrick skin types (Harris & Sundaram, 2015; Marmur et al, 2009) and in combination with other aesthetic procedures (Carruthers et al, 2016; Fabi et al, 2016b; Vanaman et al, 2016).

The results of this retrospective skin-tightening study with MFU-V and CaHA are very encouraging. Individually, MFU-V and CaHA have both demonstrated the duration of effect of at least 1 year (Werschler et al, 2016; Bass et al, 2010). It is unknown if combining the treatments will extend this further. A prospective study with longer follow-up may help to clarify this question.