more of a true skin thickness. Furthermore, ultrasound allows for repeated follow-up of the same portion of skin, which obviously cannot be the case with histology.
Ultrasound assessment and quantitative analysis by Kobus5 in patients after JVR therapy demonstrated significant (P<.05) increase in dermal thickness in different facial regions. The most substantial effect was noted in the upper lip area, where the thickness had increased by an average of 1.3 mm. At the end of the 6-month follow-up, the biggest difference was noted around the eyes, where the skin remained thicker by an average of 0.77 mm over baseline, which represented average 2.5-times increase.
Ablative lasers showed a 10.3% increase in skin thickness three months after single treatment.39 HIFU generated an increase of 23-25% two months after single treatment.27,28 Bipolar RF technology showed a 49% increase after 7 treatments.21 For Nd:YAG laser, the ultrasound measurements demonstrated a 31% increase after 6 months.43 Comparative changes in the dermal thickness are presented in Table 3.
Safety
Patients seeking aesthetic improvement are concerned by efficacy and safety of the treatment. A low pain and risk profile with minimal chances for side effects is definitely a desirable combination.
Side Effects
American Society for Aesthetic Plastic Surgery emphasizes bruising, redness, and swelling pain as the main risks following the device-based aesthetic procedures. Side effects associated with JVR are limited to occasional bruising and rare pinpoint post-inflammatory hyperpigmentation.9,34 The occurrence rate is operator-related and mainly associated with miscalculated use of excessive injection pressure due to inexperienced operator. Unnecessarily high pressure causes untoward deep penetration, bruising, and pain. Furthermore, it may induce more damage to the dermis than needed, well beyond the threshold that causes inflammation during the healing process. This could increase the risk of pinpoint postinflammatory hyperpigmentation in sensitive skin types.
Unlike JVR, lasers have been reported to cause diffuse postinflammatory hyperpigmentation, scarring, infection, and permanent hypopigmentation.40,44 IPL, although considered less harmful due to the filtration of ultraviolet radiation is also linked to blistering, hypo- or hyperpigmentation, and scarring.48 Electromagnetic radiation of RF devices (monopolar, bi-polar, and fractional) is converted to thermal energy and may produce erythema, edema, skin breakdown, and scarring.8,21 HIFU uses ultrasound beams to induce cellular damage and tissue coagulation which may induce temporary side effects of skin erythema, swelling and bruising.28 Summary of the side effects is presented in Table 4.
Pain Level
JVR treatment procedures produce minimal pain and discomfort for which no pre-treatment medication or local anesthesia required.11,34,35,53,54 The fluid jet penetrates the skin in 30 ms (average measurement; unpublished data) possibly explaining the relatively low stimulation of pain receptors. While needle injection produces a uniform vertical damage, the jet disperses immediately after penetrating the epidermis losing pressure
