Comparison of different technologies for noninvasive skin tightening
Facial skin laxity, loss of skin tightening and wrinkles are a bothersome sign of aging. In the past, the only option for treating laxity was surgery. While surgical lifting remains the gold standard, there has been a growing demand among patients for less invasive techniques. Patients are increasingly seeking procedures with little to no downtime, lower risk profiles, and a more natural appearance. The industry has responded to these demands with an emergence of noninvasive skin tightening devices. The rate of development and marketing of these devices has increased exponentially within the last decade. Whereas we previously had no options, now we are faced with many choices. How do we choose which technology is best? While there is a paucity of comparative trials to date, a critical exploration of these technologies is worthwhile. The underlying mechanism of action of all these treatments is essentially the same: heating of the dermis and subdermal areas while minimizing injury to the epidermis. In this article, we outline the different technologies and highlight the differences to help guide us in selecting the right treatment.
Radiofrequency based devices produce heating of the dermis through the application of an electromagnetic current. As electrons shift polarity and move within the tissue of the applied electrical field, heating is produced through its encountered tissue resistance according to Ohm’s law. The depth of heating is dependent on several factors including the tissue’s unique impedance, frequency of the current, cooling applied, and the type of electrodes. Histologically, irreversible collagen denaturation is seen instantaneously even with a single pass of monopolar RADIOFREQUENCY. The subsequent wound remodeling over time then creates the skin tightening effect that peaks over a 3–6 month period. Facial sites treated with a monopolar RADIOFREQUENCY device showed a significant increase in both type I and type III collagen 3 months after treatment. Using birefringence examination, there is evidence that this increase included newly synthesized collagen formation.
Radiofrequency was the first technology to be studied and developed for noninvasive skin tightening, and there has been significant development since (Table 1). In 2002, the first monopolar RADIOFREQUENCY device (ThermaCool TC; Thermage Inc., Solta, Haywood, CA, USA) was approved by the FDA for noninvasive treatment of periorbital wrinkles and rhytides. This monopolar RADIOFREQUENCY device produces 3-dimentional volumetric heating as the current flows from the handpiece to grounding pad. The initial device dispersed the heat at a controlled depth of 3–4 mm using a unique capacitive coupling mechanism. The depth and volume of effect depends on the size and geometry of the device tip.The pivotal study to demonstrate this effect was done by Fitzpatrick et al. After a single treatment on the forehead and temple, 61.5% of the 86 patients demonstrated an eyebrow lift of at least 0.5 mm on photographic analysis at 6 months post-treatment. Side effects included erythema (36%), edema (14%), and epidermal burn (0.4%), all of which were transitory without long-term sequelae. Evidence for the use of this device on the upper and lower face was subsequently demonstrated, and further FDA approval was obtained for improvement of facial wrinkles and skin tightening in 2004. In an early study of the lower face, 10 of 16 patients found the result to be unsatisfactory. However, a subsequent study of 50 patients treated with the monopolar RADIOFREQUENCY device on the lower face using a single high fluence pass found significant improvement in cheek and neck laxity in the majority of patients. Blinded evaluation of photographs 6 months post-treatment demonstrated a mean clinical improvement score of the nasolabial folds of 1.53, where 1 corresponds to 25–50% and 2 corresponds to 51–75% improvement. In a split-face comparative trial of treatment vs. no treatment, a mean decrease of 22.6% in two-dimensional suRadiofrequencyace area was observed on the treated side after a single treatment of the jowls of the lower face. There were no changes of suRadiofrequencyace area on the nontreated side.
Current manufactured radiofrequency (RADIOFREQUENCY) devices for facial skin tightening
|Product/Manufacturer||Category of Device||Special features|
|Thermage (Solta Medical)||Monopolar RADIOFREQUENCY||Capacitive coupling technology, multiple size tips for facial and body treatment|
|Pelleve (Ellman International Inc.)||Monopolar RADIOFREQUENCY||Multiple size tips, continuous motion, facial and body treatment, surgical electrocautery capability|
|Exillis (BLT Industries, Inc.)||Monopolar RADIOFREQUENCY||Constant temperature control on device, depth of penetration related to amount of cooling, facial and body handpieces|
|eMatrix, eTwo (Syneron)||Fractionated bipolar RADIOFREQUENCY||Sublative technology with minimal epidermal injury and wider dermal heating|
|elōs (Syneron)||Bipolar RADIOFREQUENCY + Intense Pulsed Light||Synergistic skin tightening and photorejuvenation|
|ePrime (Syneron)||Microneedle bipolar RADIOFREQUENCY||Bipolar electrodes introduced to specific depth through microneedles|
|Accent (Alma Lasers)||Unipolar RADIOFREQUENCY and Bipolar RADIOFREQUENCY||Two handpieces to deliver each type of RADIOFREQUENCY on one platform, facial and body treatment capacity|
|Venus Freeze (Venus Concept)||Multipolar RADIOFREQUENCY + Magnetic Pulsed Fields||Facial and body skin tightening|
|EndyMed PRO 3 (EndyMed Medical)||Multipolar RADIOFREQUENCY||Real time skin impedance readings, Handpieces for facial and body sites|
The limitations of this early device were long treatment times, intolerable pain, but most importantly modest and unpredictable results. Over time, modifications to the RADIOFREQUENCY source, to the delivery tips, and to treatment protocols, have produced less discomfort, shorter treatment times, and better results. The treatment protocol was modified based on a pivotal histologic study. Similar collagen effects were seen on electron microscopy with one high fluence RADIOFREQUENCY pass and multiple, low fluence RADIOFREQUENCY passes. Furthermore, deeper effects on collagen were seen with increased numbers of passes, thus contesting the need for a single, more painful high energy pulse. Clinically, this protocol was confirmed to produce more predictable outcomes with a large investigation by a multispecialty consensus panel. In a survey of 5700 patient treatments, the original treatment algorithm of high energy delivered over a single pass vs. a new algorithm of lower energy with multiple passes was compared. At the 6 month endpoint, 54% of the original algorithm patients vs. 92% of the new algorithm patients noted skin tightening. Additionally, 45% of the high energy, single pass patients found the procedure too painful compared to only 5% in the lower energy, multiple pass group. Currently this lower-fluence, multiple pass protocol is the standard of care for this monopolar RADIOFREQUENCY device. Larger tips, which deliver more uniform and deeper energy delivery, have also been developed to take advantage of this critical information to optimize outcomes. The evolution of the various treatment handpieces for the Thermage device. From left to right Thermage Cellulite 3.0, Thermage Face 3.0 NTX, Thermage Face 3.0 CPT, Thermage Body 16.0 (orange), Thermage Eye 0.25 (green), Thermage Total 3.0 (orange), and Thermage eye (original tip, not manufactured). (Courtesy of Solta Inc.). Grid placement for ease of utilizing the multiple pass, lower fluence per pulse technique (Courtesy of Solta Inc.).
There are other devices using monopolar RADIOFREQUENCY, which differ in their emission frequency, handpiece, and treatment protocol. A 4-Mhz device (Pelleve; Ellman International, Inc., Oceanside, NY, USA) uses a continuous motion technique with various size handpieces ranging from 7.5 to 20 mm in diameter, allowing for treatment of both smaller and larger facial areas. Seventeen patients completed six full face treatments using a combination of 5 and 10 mm handpieces, selected to administer both superficial and deep heating. One year after starting treatments, corresponding to 6 months after the final treatment, physicians rated a 46% average improvement from baseline photographs and patients reported a 30% overall improvement of skin tightening. There was minimal to no associated pain and no side effects reported. A series of treatments spaced 4–6 weeks apart are typically performed. An additional device termed dynamic monopolar RADIOFREQUENCY (Exilis; BLT, Framingham, MA, USA) also uses a continuous motion technique with an attached temperature sensor and novel cooling system within the treatment handpiece. The cooling is adjusted to control the depth of heating as less cooling will allow the heat to reach deeper into the subcutaneous tissue. Approved by the FDA in 2009 for the noninvasive treatment of wrinkles, it is commonly used on the face, although the published data on the use of this device has been limited to body contouring.
Another route of delivering RADIOFREQUENCY to the target tissue is unipolar RADIOFREQUENCY technology. This is where only one electrode is present without a grounding pad. An electromagnetic radiation field is emitted in an omnidirectional area around this electrode. Unipolar RADIOFREQUENCY has a theoretical depth of penetration up to 20 mm, penetrating deep into the subdermal plane, and therefore is used more frequently for body contouring. Unipolar RADIOFREQUENCY technology can be found in a combination device with bipolar RADIOFREQUENCY capabilities on the same platform (Accent, Alma Lasers, Caesarea, Israel). In a split-face study of 10 patients, each side was treated with either the unipolar or bipolar modality. Both sides did not show significant improvement in skin tightening after four weekly treatments.Yet in another study of the same device, using both the unipolar and bipolar settings over four to six treatments, a majority of patients were rated on photographic analysis as having 51–75% improvement of the cheeks and jowls.
Since the introduction of monopolar RADIOFREQUENCY technology, many variations of RADIOFREQUENCY have emerged for skin tightening. In bipolar RADIOFREQUENCY, the current runs between the two electrodes on the treatment tip and a grounding pad is not needed. The advantage over monopolar RADIOFREQUENCY is a controlled, predictable depth of heating, but this depth is more superficial as it is restricted to half the distance between the two electrodes. This depth usually corresponds to 2–4 mm within the dermis.
Bipolar RADIOFREQUENCY devices are frequently combined with other optical energy sources, such as intense pulsed light (IPL) or a 900 nm diode laser, for potentially synergistic effects. The optical energy heats the dermis, lowering the tissue impedance, theoretically enhancing the effects of the RADIOFREQUENCY energy. Studies of this combined technology rarely specifically evaluate the effect on skin laxity, but rather wrinkles and skin texture. A prospective study using a combination 900 nm diode laser and bipolar RADIOFREQUENCY device (Polaris WR, Syneron, Yokneam, Israel) for treatment of wrinkles found that more than half of the 23 subjects demonstrated >50% improvement in wrinkles after three treatments. A large, uncontrolled study of 108 patients treated with a combination IPL and bipolar RADIOFREQUENCY device (Aurora SR, Syneron, Yokneam, Israel) showed overall skin improvement and improvement in skin laxity of 75.3% and 62.9%, respectively, on double-blinded physician photographic evaluation. The above mentioned devices are not currently in manufacturing, but the new marketed device (elos Plus; Syneron, Irvine, CA, USA) has the bipolar RADIOFREQUENCY, diode and IPL combination on a single platform, with each unique handpiece having a combination of two of these energy sources.
Bipolar RADIOFREQUENCY has also been combined with a vacuum system, and these devices are termed functional aspiration controlled electro thermal stimulation (FACES). The vacuum brings the target tissue closer to the applied current, thereby maximizing depth of penetration over bipolar RADIOFREQUENCY alone. In a study of this technology, 46 participants had eight treatments (Aluma; Lumenis, Santa Clara, CA, USA; no longer manufactured) and were evaluated using the Fitzpatrick-Goldman Classification of Wrinkling and Degree of Elastosis Scale. The subjects’ mean score improvement corresponded to a reduction of full wrinkle class on this scale at 6 months post-treatment. Interestingly, the original investigation of monopolar RADIOFREQUENCY applied to periorbital region using the high fluence, single pass algorthim was also measured on this scale. At 6-month follow-up, 29% of the monopolar RADIOFREQUENCY subjects experienced at least one unit of improvement on the Elastosis Scale; 85% of the bipolar RADIOFREQUENCY combined with vacuum subjects experienced equivalent results.
Fractional RADIOFREQUENCY technology is another form of RADIOFREQUENCY treatment. It can be delivered by using a fractionating tip on the skin surface or by using an array of needles inserted into the skin. While RADIOFREQUENCY devices generally do not affect the epidermis, these new devices deliver the bipolar RADIOFREQUENCY energy through microchannels, utilizing the same principles of cutaneous healing as nonablative fractional resuRadiofrequencyacing lasers.
Certain devices use treatment tips with parallel rows of bipolar electrode pins to create closed circuits amongst these pins (Fig. 3). The density of pins and emitted energy control the depth and amount of ablation. The multiple electrodes create many pyramidal shaped zones of injury resulting in a small amount of epidermal disruption overlying a wider area of heating in the deeper tissue. Demarcated zones of ablation and coagulation on human abdominal skin ranged from 100 to 450 μm in depth (Matrix RADIOFREQUENCY/eMatrix, Syneron). The 44 and 64 electrode density tips created deeper thermal effects histologically and greater improvement in wrinkles clinically compared to the 144 electrode tip which showed epidermal disruption and greater effect on supeRadiofrequencyicial photodamage. In terms of efficacy for skin tightening, after three monthly treatments (Matrix RADIOFREQUENCY/eMatrix, Syneron) in 36 patients, an improvement of 40% or greater in skin tightening was found in 55% of patients, yet no statistically significant decrease in wrinkling and elastosis scores were found. No side effects or significant downtime was reported.
Fractionated radiofrequency; an example of the eMatrix treatment tip demonstrating the electrodes and the flow of energy (Courtesy of Syneron/Candela).
A different bipolar fractional RADIOFREQUENCY device uses microneedles as a delivery system. The microneedles insert into the reticular dermis, arranged in pairs, and bipolar RADIOFREQUENCY energy is delivered between them. Histologically, it has been shown to induce a vigorous wound healing process, neocollagenesis, and neoelastogenesis (Renesis, Primaeva Medical Inc., Pleasanton, CA, USA). In a randomized, blinded, quantitative study, the microneedle fractional RADIOFREQUENCY device (Miratone, Primaeva Medical Inc.) resulted in a 16% improvement in skin laxity on the face.In a recent, prospective, split-face comparative study of 12 healthy women, Botox A injections resulted in better improvement in periorbital rejuvenation at 1 month but microneedle fractional RADIOFREQUENCY was superior at 3 months. Hyperpigmentation on the microneedle fractional RADIOFREQUENCY side was reported in two patients, which resolved spontaneously within 2 months. The Renesis and Miratone device are now more commonly known as the ePrime device (Syneron). A prospective study of 10 patients undergoing one treatment of 110-130 insertions per side (ePrime, Syneron) on the lower face demonstrated lifting with 3D imaging. Clinical assessment noted reduction of the jowls and elevation of the malar prominence. Three dimensional imaging documented an increase in volume of the face and an elevation of 1.79 mm at 4 months.
Lastly, a device that uses multipolar radiofrequency in combination with pulsed electromagnetic fields (Venus Freeze; Venus Concept, Karmiel, Israel) has been shown to affect facial skin tightening. After a series of 10 treatments, 30 of 31 patients were rated by blinded physicians as having at least a 1 grade improvement in the Fitzpatrick Wrinkle and Elastosis Scale 3 months after the last treatment. All treatments were rated as pain free using a visual analog scale. A similar device which utilizes multisource radiofrequency (EndyMed Pro, EndyMed Ltd, Cesarea, Israel) has the ability to monitor real-time skin impedance measurements during treatment. This device also has multiple treatment handpieces for face and body contouring, including one to perform fractional skin tightening.
Skin tightening has also been demonstrated with infrared light devices and lasers. Wavelengths in the infrared spectrum are absorbed by water in the skin causing dermal heating. For example, a device with a wavelength range from 1100 to 1800 nm was found to cause immediate skin tightening with effects lasting up to 12 months in 22 of 25 patients using fluences ranging from 20 to 40 J/cm2. (Titan; Cutera, Inc., Brisbane, CA, USA) Treatments were well tolerated without the use of anesthesia. Three patients had small, superficial, second-degree burns that healed uneventfully. Subset analysis demonstrated that better results were achieved with a fluence of 30 J/cm2 and 150–360 pulses when compared to a fluence of 20–25 J/cm2 and <150 pulses. Skin tightening was also found in older individuals and in an Asian population. In both these latter studies, treatment was performed twice, 1 month apart. Among lasers studied for their tightening effects, a 1450-nm diode (SmoothBeam, Candela Corporation, Wayland, MA, USA) was shown to lead to modest improvements in wrinkles: 15% of patients had moderate improvement, 50% had mild improvement, and 35% had no obvious change.In addition, treatment with a 1320 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (New Star model 130 Nd:YAG laser; New Star Lasers, Auburn, CA, USA) has been shown to improve severe wrinkles. Combination wavelength techniques have also been investigated. After 3-6 treatments of combination of long pulsed 532-nm potassium titanyl phosphate (KTP) laser (Aura laser; Laserscope, San Jose, CA, USA) and long pulsed 1064- Nd:YAG laser (Lyra laser; Laserscope), patients were found to have a 40–60% improvement in skin tone/tightening.
Laser resurfacing and skin tightening
Laser resurfacing and skin tightening have also been found to induce skin tightening. The more heat delivered by the device, the more likely it is to tighten skin. While nonablative devices for the most part induce little or no tightening of skin, ablative devices, especially CO2 lasers, are more likely to tighten skin Fractional devices are less likely to do so compared with nonfractional ones. While the authors acknowledge the invasive nature of ablative resurfacing, we find it important to report its effects in regards to skin tightening while reviewing the literature and comparing available technologies.
Nonfractional carbon dioxide (CO2) (UltraPulse CO2 laser; Coherent Medical Group, Santa Clara, CA, USA) and erbium lasers (Derma K; ESC Medical Systems, Needham, MA, USA) were reported to induce an average of 43% and 42% tightening, respectively, which gradually diminished to 34% and 36% by 6 months. Due to the unfavorable side effect profile of the traditional CO2 and erbium lasers, fractionated CO2 laser technology was explored for its role in skin smoothing and tightening. Several recent studies have reported tightening with ablative fractional photothermolysis. Tierney et al. demonstrated 65.3% mean improvement in lower eyelid skin laxity with a series of 2–3 fractional CO2 laser treatments (SmartXide Dermal Optical Thermolysis (DOT laser); Eclipse Med, Dallas, TX, USA). In another study of periorbital skin, all patients showed global improvement in eyelid skin tightening with 11.1% demonstrating excellent improvement, 24.5% marked improvement, and 33.3% moderate improvement (SmartXide DOT; DEKA-M.E.L.A., Calenzano, Italy). Nonablative fractional photothermolysis has also been investigated for its role in skin tightening and has been found to induce facial skin tightening. In one study, all patients treated with a 1550-nm erbium-doped fiber laser (Fraxel 750 SR laser; Reliant Technologies Inc., Mountain View, CA, USA) on 3–7 occasions experienced some degree of eyelid tightening: 28% achieved 1–25% improvement, 26.9% achieved 25–50%, 25.8% achieved 50–75%, and 19.4% achieved 75–100%. In an animal model, however, the skin tightening effects of nonablative and ablative fractional lasers were compared, and the ablative fractional laser (10 600 nm eCO2®; Lutronics Co., Gyeonggi-do, Korea) was found to induce significantly more skin tightening than the nonablative fractional laser (1550 nm Mosaic®; Lutronics Co., Gyeonggi-do, Korea).
Intense focused ultrasound energy tightens skin by delivering thermal energy to the dermis and subcutis. Zones of coagulation are produced within the highly focused beam from the absorption of this acoustic energy within the tissue. From porcine soft tissue and postmortem human skin examinations, the focused beam delivered in milliseconds is configured to produce zones of coagulative necrosis approximately 1 mm3 in diameter or smaller. The depth and volume of these zones are determined by the preset focus depth, frequency, and energy delivered by a given probe.
The FDA approved device (Ulthera, Ulthera Inc., Meza, AZ, USA) contains several probes of different frequencies with the higher frequency probes producing a more superficial tissue effect. This ultrasound device was initially FDA approved in 2009 for noninvasive eyebrow lift. While treating the forehead, temples, cheeks, submental, and lateral neck areas with various probes, Alam et al., demonstrated objective eyebrow elevation. From 35 subjects, comparing measurements from fixed landmarks on photographs, a mean average change in eyebrow height was 1.7 mm at 90 days postprocedure. From blinded physician evaluation of paired photographs, 30/35 (86%) were observed to have clinically significant improvement of eyebrow position. Pain scores were on average 3-4 on a 10-point scale, but five subjects reported a pain score >7. There were no serious adverse events.
In 2012, the FDA approved this same ultrasound device for skin lifting of the neck and submental area. Lee et al. applied two passes, a single pass of each the 4-MHz, 4.5 mm probe and the 7-MHz 3.0 mm probe to the face and neck. Blinded evaluators of photographs comparing baseline and 90 days post-treatment demonstrated 8 of 10 subjects with clinical improvement, 50% with moderate improvement. Mean pain was rated at 3.9 out of 10.
The tissue response from these thermal coagulative changes is similar to other heating devices such as radiofrequency and ablative resuRadiofrequencyacing, but differs in that the heat is only directed within the intense, focused beam and not in a volumetric manner. This creates similar histologic changes to fractional nonablative devices, but its advantage is complete sparing of epidermal injury. Intense focused ultrasound is able to cause collagen denaturation within the superficial musculo-aponeutroic system (SMAS) which leads to tissue tightening on a deeper plane then the other types of devices. Clinical results of tightening from specifically heating the SMAS with this device have not yet been reported, but could theoretically product an enhanced tightening effect over other technologies unable to target the SMAS.
Variation in pain reported during treatments with this device has ranged from as little as all patients reporting minimal pain to studies where 14% of patients reporting pain greater than seven on a 10-point scale. Some physicians choose to pretreat patients with oral anxiolytics and oral or intramuscular narcotic analgesic.Recent upgrades to the software (AMPLIFY software; Ulthera Inc.) made in October 2012 have improved patient comfort and have reportedly reduced pain. (M. Likens, Ulthera, personal communication, May 9 2013) These changes include the utilization of lower energy levels and multiple passes, not dissimilar to the changes adopted by the monopolar RADIOFREQUENCY (Thermacool TC) device earlier.
Studies which directly compare noninvasive technologies for skin tightening are rare. Only three comparative studies were found in the literature to date, two of which compare the same devices. Key evaluated 12 patients in a split-face study of monopolar RADIOFREQUENCY (ThermaCool TC, Thermage, Inc.) vs. long-pulsed 1064 nm Nd:YAG laser (Gentle YAG, Candela Corporation, Wayland, MA, USA). Each patient received one treatment with the low-fluence, multipass technique of monopolar RADIOFREQUENCY to a single side and one treatment with multipass technique, long-pulsed (50 ms) 1064 nm laser to the other. From photographic comparison, an improvement was noted on the lower face for each device, but there was not a statically significant difference between the two sides. In an overall enhancement rating, the laser side was significantly improved over the RADIOFREQUENCY. Both treatments did not have any downtime or side effects noted. In the other split-face, comparison study of these same two devices, photographic comparison found greater improvement for wrinkles and laxity on the laser treated side. Between these two studies, the number of pulses of RADIOFREQUENCY applied and the energy of the laser differed, making comparison between them difficult.
Comparing unipolar vs. bipolar RADIOFREQUENCY, a spilt-face trial using a device with a handpiece for each technology (Accent, Alma Lasers, Caesarea, Israel) was performed. Ten patients randomized to receive a treatment on one side of the face with unipolar RADIOFREQUENCY and the contralateral sides treated with bipolar RADIOFREQUENCY were evaluated. Neither side achieved a statistically significant clinical improvement, but both trended toward improvement. There were no differences in pain or side effects between the sides.
Lastly, in a valuable evaluation, Alexiades-Armenakas et al. compared mirconeedle bipolar fractional radiofrequency (FRADIOFREQUENCY) (Miratone, Primavea Medical Inc, Pleasonton, CA; now the ePrime, Syneron, Irvine, CA) with surgical face lifting, the gold standard for skin tightening. Fifteen patients underwent one treatment of the lateral mid and lower face with a FRADIOFREQUENCY device and five patients received a surgical face-lift. Photographs of 21 patients from baseline and 6 months post-treatment were analyzed using a validated skin laxity scale by blinded, nontreating physicians. The analysis demonstrated a mean 1.20 grade improvement for the surgical procedure vs. a mean 0.44 grade improvement for the noninvasive modality. This corresponds to a 49% improvement from baseline for a surgical face-lift and a 16% improvement for FRADIOFREQUENCY treatment, the difference between the two treatments being 37%. This comparison highlights the finding that noninvasive modalities do not produce the same extent of skin tightening as surgical intervention but still demonstrate a modest effect, and this difference has now been quantitatively demonstrated. This is important for preprocedure guidance of patient expectations.
As technologies continue to emerge to meet the growing demand for noninvasive skin tightening, the data supporting many devices continues to accumulate at a rapid speed. It has been shown, in one setting or another, that all of these devices are effective. They all produce some degree of skin tightening and demonstrate the histologic alterations to create these changes. They all have little to no downtime and a low-risk, side effect profile. Yet, the major question now arises: how do we compare these devices for predictable patient outcomes?
The comparison of these new technologies is difficult due to many factors. First, when comparing individual studies of the various technologies, the methods of data collection vary from study to study. These methods range from nonstandardized photography to computer-generated measurements from fixed landmarks. Second, the clinical endpoints evaluated differ among the studies. Whereas some focus on the impact on skin laxity, some measure wrinkle reduction, some evaluate acne scarring improvement, while others measure overall skin rejuvenation. Lastly, the scales for measuring specifically skin laxity are often subjective and diverse, making it inherently difficult to compare results. Difficulty lies in quantifying skin tightening on the lower face, as there are no fixed landmarks from which to measure changes as exist in the upper face. Scales to quantify the changes seen with skin tightening need be uniform and standardized amongst studies to successfully compare effectiveness.
It is also important to note the improvements to treatment protocols and devices made throughout the years when attempting to compare devices. These changes are made to attempt to have better and more predicable outcomes and an improved patient experience. Therefore, earlier investigations of devices may not be able to be compared to more recent studies.
What we really need in this growing aspect of our field is controlled, comparison studies utilizing standardized scales. However, it is unlikely that such comparison studies will be performed because the companies have little incentive to initiate these side-by-side comparisons due to the high cost but more importantly the concerns of a negative outcome for their device.
Overall, the effects of noninvasive skin tightening are modest at best but appear to be long-lasting. These technologies all work, but patient selection is paramount. In the opinion of the authors, the ideal candidate has little laxity, but patients with more severe laxity should not necessarily be excluded as they too are seeking less downtime and minimal risk. Engaging patients in full discussion about the usefulness of these technologies and managing expectations is crucial for patient satisfaction.
Rachel N. Pritzker MD, Heather K. Hamilton MD, Jeffrey S. Dover MD, FRCPC, FRCP
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