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A Systematic Review of Subsurface Radiofrequency Treatments in Plastic Surgery

Background Subsurface radiofrequency (RF) treatments produce skin contraction by causing coagulation of the underlying subcutaneous fat. This method is marketed to fill a treatment gap for patients who do not wish to have surgery. A systematic review of this subject has not been previously published. Methods An electronic search was performed using PubMed to identify the literature describing subsurface RF treatments. Results Thirty articles were evaluated. An InMode device was used in 23 studies, and a Thermi device was used in 6 studies, with or without liposuction. Treatment areas included the face, neck, body, breasts, and labia. Most studies relied on patient satisfaction scores and physician review of photographs. The most frequent complications were induration and nodules. Most patients experienced prolonged swelling and numbness. Several studies reported marginal mandibular neuropraxias. The skin response after treatment of the abdomen was poor, and seromas were common. The incidence of burns improved after modification of the InMode device. Breast treatment did not appear to be effective in treating ptosis. Patient satisfaction scores were modest. Most studies (77%) were published by authors with a known conflict of interest. In some studies, the photographs did not accurately depict the treatment result. Institutional review board approval and disclosure of off-label regulatory status were often missing. Discussion Thermal treatment of the subcutaneous tissue introduces extra risks without a compensatory benefit. Comparisons in terms of safety, cost, recovery time, results, and complications do not favor energy-based devices. A treatment gap may be fictitious; properly informed patients may be treated with existing surgical procedures at all ages. Conclusions Little evidence supports the efficacy and safety of subcutaneous RF treatments as an improvement over results that may be obtained using traditional surgical methods such as submental lipectomy, liposuction, and abdominoplasty. Photographic integrity is often lacking. Financial conflict of interest is pervasive. Marketing precedes the science. Plastic surgeons need to be aware of these serious limitations and the off-label regulatory status of these devices, before purchasing expensive equipment and recommending subsurface RF treatments to patients.


RESULTS
Thirty unique articles evaluating subsurface RF treatments were identified (Table 1). 9, In 23 studies (77%), an InMode product was used. A Thermi product was used in 6 studies (20%). One Korean study used a similar monopolar device. 26 Two recent articles published in 2019 and 2020 report the same findings in the same 247-patient population. 11,40 Data from the first published study were tabulated. 11 No prospective randomized studies that include a control group have been published. Data heterogeneity precluded a meta-analysis. Most authors (67%) also used liposuction in some or all patients. The median number of study patients was 25 (range, . The most common treatment areas were the neck (57%), trunk (37%), upper arms (37%), and face (33%). Local anesthesia was used in 9 studies, and general anesthesia in 8 studies. Three studies used local anesthesia in some patients and general anesthesia in others. The tissues were routinely tumesced. Five studies used oral sedation. Intravenous anesthesia was used in 3 studies. Treatment times ranged from 45 minutes for the face and neck 28 to 102 minutes, on average, for multiple areas. 33 Breasts required 60 to 90 minutes. 36 The average treatment time for the "Embrace" protocol, combining FaceTite with topical RF (Morpheus8, InMode), was 58 minutes. 40 Many investigators used forward-looking infrared imaging to monitor the surface temperature, 9,16,23,31,39 especially when using the Thermi device.
Variable posttreatment protocols were described. Turer et al 39 applied paper tape on the neck covered by foam and a Velcro chin strap, worn for 3 to 6 days. Patients were instructed not to shower for 1 week. A garment was worn intermittently while at home and at night for the next 3 weeks. Strenuous activity was prohibited for 4 weeks. After treating the abdomen with the BodyTite device, Hurwitz and Smith 17 instructed patients to apply compression foam for 5 to 7 days and then shower. Elastic garments were recommended for 3 weeks. Induration was treated with massage and low-level laser treatments. 17 Eleven studies (37%) reported no complications. Cook et al 36 reported adverse events in 19% of patients; half of these cases were prolonged swelling. Keramidas and Rodopoulou 28 reported hardness of the subcutaneous tissue of the neck in 9% of patients, requiring daily massage for 3 months.
Dendle et al 29 reported that the most common adverse effects after Thermi treatments of the face and neck were tenderness (63%), edema (89%), bruising (52%), numbness (82%), and nodules or induration (19%). The most frequently reported complication reported among all studies was hardening of the subcutaneous tissue, producing induration and nodules. 11,17,22,25,28,29,36,37 These areas frequently took months to soften. Seromas requiring serial drainage commonly occurred after treating the abdomen with the BodyTite device. Some operators routinely inserted a drain when treating the abdomen and left it in place for up to 14 days. 18,41 Hurwitz and Wright 42 retreated the abdomen in 25% of cases and routinely treated loose skin with Morpheus8 RF microneedling. Seven cases of neuropraxia of the marginal mandibular nerve were reported among the 30 studies. 11,28,29,33 Most articles reported subjective methods of evaluation, such as patient satisfaction scores (67%) or physician evaluation of before-andafter photographs (43%). Paul and Mulholland 9 measured distances between 2 surface landmarks, such as moles or the umbilicus, using a flexible ruler. These authors reported a linear contraction varying from 12.7% to 47% 6 months after RF-assisted liposuction. The authors noted that the soft tissue contraction would be much greater, calculated as the square of linear contraction. A 47% linear contraction would theoretically produce a 72% reduction in surface area (1-0.53 Â 0.53). Measurements on photographs from other studies reveal lesser degrees of skin contraction (Fig. 1).
Duncan 22 used tattooed markers to facilitate surface measurements. This investigator studied 12 patients in whom RF-assisted liposuction was used on one side of the abdomen and not on the other, finding a greater reduction in surface area measurements (36%) for patients receiving RF assistance compared with liposuction alone (8%) at 1 year follow-up. However, in some cases, the skin "buckled" in the heated areas, causing greater skin laxity on the heated side. Other investigators also reported inadequate skin tightening after subsurface RF treatment, leaving skin redundancy and wrinkling. [15][16][17] Hurwitz and Smith 17 attributed this progressive wrinkling to contracture of the subcutaneous tissue beyond the shrinkage capability of the overlying skin.
In 2015, Chia et al 24 compared RF-assisted liposuction of one upper arm with unassisted liposuction of the other upper arm. The authors reported a 13% surface area reduction for RF-assisted liposuction versus an 8% reduction for the control arm at 1 year. The differences between treatments were not statistically significant.
A recent retrospective study by Cook et al 36 reported a large experience (n = 745) using the InMode device on multiple areas, including the neck, trunk, arms, and breasts (Fig. 2). Another study published almost simultaneously reported a prospective study of patients treated 26 39 Photographs from other studies showed less dramatic results (Fig. 3). Some studies using the BodyTite device on the abdomen included photographs of patients who also had abdominoplasties or a surgical diastasis repair. 11,14,15,17 One patient had a "mini neck-lift" in addition to a FaceTite treatment. 14 Most articles (77%) were published by authors with known financial conflicts. In 5 studies, no financial conflicts were reported, 13,14,22,29,35 but at least 1 of the authors was known to have a conflict that was reported in another contemporaneous study. Many of the authors were paid consultants. Some also held ownership positions in the form of stock options. Two authors also served as chairmen of the medical advisory board of InMode (formerly Invasix). 9,12,[32][33][34] Investigators were often allowed to keep their InMode BodyTite devices (US $205,000) 10 after their study without paying for the device. 12,16,20 Duncan 22 reported that she voluntarily returned her InMode device after using it at no charge for her study. Key 23 was the only  author to report no financial conflicts and the fact that he purchased his RF equipment.

Financial Conflict of Interest
Financial conflict of interest is a major problem in medicine today. One entire issue of the Journal of the American Medical Association was dedicated to this subject. 43 Publications on this topic have also appeared in the plastic surgery literature in recent years. [44][45][46] The dollar amount of a conflict of interest does not need to be substantial to be effective. 47 Even small gestures, such as paying for meals, build a sense of reciprocity.
The full extent of this financial conflict is often undisclosed to the reader. Such conflicts include direct payments to doctors, providing expensive equipment for studies at no charge (the doctors just keep the equipment), referral fees, payments for speaking and traveling, and funding for clinical trials. An author may also serve as an officer of the company or hold an ownership interest. 45 Authors are often listed in the disclosure paragraph of publications as consultants. These physicians are recruited and heavily reimbursed to conduct studies that are published in plastic surgery journals. Plastic surgeons' services are not simply to provide advice to the company (the true role of a consultant), which would be at a much lower hourly fair market price. 45 In response to this problem, the "Sunshine Act," part of the Affordable Care Act, was passed by Congress to provide transparency to the public regarding payments their doctors receive from industry. Medical device companies are required to disclose these payments. 48 Surprisingly, there is no record on the Propublica "Dollars for Docs" website of InMode payments to its numerous paid consultants. 49

Photographic Integrity
Plastic surgeons and patients rely heavily on photographs. Photographic integrity is therefore essential. 1 A 2019 publication claimed to show the results of InMode BodyTite treatments in combination with RF microneedling using the Fractora (InMode) device, later replaced by the Morpheus8 device. 11 The study included photographs of 1 patient who also underwent an undisclosed abdominoplasty (Fig. 4). 50 In a set of facial photographs contained in the same article, the mandibular border was lightened to soften the appearance of jowls. A third patient appears to have had undisclosed liposuction of the back.
A 2015 study 24 determined that the percent change in linear measurements on the treated skin of the upper arms exceeded the percent change in area measurements, which is geometrically impossible. 51 These patients also received liposuction, which can produce skin tightening on its own (Fig. 5), without energy treatment. 24 Photographs of patients who were not actually in the study were published. 51 In a recently published study, the photographs showing "typical" 6-month results of a single Thermi treatment without liposuction are extraordinary. 39 Two patients appear to have a full correction of submental adiposity and a major improvement in skin laxity of the lower face and neck-a result rivaling a facelift. Thermi funded the study featuring these excellent results and even provided writing assistance. 39 Remarkably, this corporate sponsor held "final responsibility for the study design, collection, analysis, and interpretation of data; and the writing and the decision to submit the manuscript for publication." 39 One set of photographs did not depict a study patient. 22 The photographs were provided by another surgeon. The patient is standing more upright in the postoperative photograph, and the lower part of the abdomen is concealed by panties who are pulled up much more than they were preoperatively. Another article also covered the lower abdomen in a postoperative photograph. 9 Published photographs were frequently not properly standardized. 29,32,33,39,40 In the postoperative photograph, the patient's image was often smaller 28,33 or the chin was lifted, 29,39 or both. 33 In a study using FaceTite and AccuTite devices to treat hypertrophic labia, the labia minora were spread open in the before photograph and brought together in the after photograph. 32

Patient Satisfaction
Many studies reported high levels of patient satisfaction. [12][13][14]32 Others reported more modest patient satisfaction scores. 28,29,37,39 Sixty-eight percent of the patients in the industry-sponsored study by Turer et al 39 expressed satisfaction, and almost the same percentage (67%) of patients would recommend the treatment. Similarly, Dendle et al 29 reported that 64% of their patients were satisfied after a Thermi treatment. Han et al 37 reported that 21% of patients considered their results from FaceTite-assisted liposuction to be poor or thought that there was no change. Another study using this InMode product reported that 15% of patients were unhappy. 28 RealSelf.com 52 is a highly popular online plastic surgery forum that features patient reviews of plastic surgeons and procedures. This site avoids the influence of industry sponsorship and can help gauge patient satisfaction among a large number of online reviewers. Patientrated "Worth It" scores for BodyTite and ThermiTight are 76% and 70%, respectively ( Table 2).

Patient Safety
Radiofrequency (electrical) energy flows from the tip of the internal probe to the external electrode of a bipolar BodyTite device, heating the adipose tissue and the dermis from below. 9 The temperature  around the tip of the probe reaches 70°C to 80°C. 9,33 The external electrode contains a temperature sensor. The device shuts off at a selected temperature. Bell signals indicate when the goal temperature is reached. 53 Ultrasound gel is applied liberally to the skin surface. 33,34 The Thermi device is monopolar; the current is dispersed into the local adipose tissue and collected by a distant grounding electrode. 31 The internal probe includes a temperature sensor. An infrared camera (FLIR Systems, Wilsonville, OR) 23,39 monitors the skin temperature. 31,53 Some authors keep ice on the field in a sterile glove as a precaution. 39 Because the heat is applied to the deep surface of the skin, any burn is full thickness and some burns will require surgical revision. 41 Ahn et al 14 caution operators not to pass the internal probe too deeply in the face to avoid fat necrosis and a resulting contour depression, or injury to the facial nerve. Unlike most operators, who prefer to stay superficial in the face, Cohen et al 35 insert the probe deep to the superficial musculoaponeurotic system.
Introducing a heated probe directly in the vicinity of the marginal mandibular branch of the facial nerve is likely to put this important nerve in jeopardy. The thermal injury is not tissue specific. Nerves close to the probe are likely to be damaged along with fat. When the Thermi study was undertaken from 2016 to 2017, 39 a contemporaneous study was conducted to investigate the path of the marginal mandibular nerve among the same patients. 54 This study included a nerve stimulator and careful mapping of the nerve, and skin marking. 54 This nerve-mapping study and the use of a nerve stimulator are not referenced in the (corporate-sponsored and writing-assisted) clinical study. 39 No nerve injuries were reported in either study. 39,54 Some authors recommend routinely mapping the marginal mandibular nerve using a nerve stimulator when treating the face and neck. 53,55 Several surgeons mark the anticipated course of the marginal mandibular nerve routinely before starting the procedure. 33 The average operating time by treatment area is increased when RF assistance is used. 18 When treating awake patients, lidocaine toxicity is a concern. Theodorou et al 18 reported that lidocaine doses exceeded 35 mg/kg in 33% of their BodyTite-assisted liposuction cases. These authors called for caution when treating convex areas to avoid end hits and a rapid increase in temperature that can cause a burn. 18 Seromas are common. 17,18,41,42 These fluid collections likely result from injury to the subcutaneous and subdermal lymphatic system. 41 Mulholland 41 and Theodorou et al 18 insert drains in all patients undergoing RF-assisted abdominal liposuction. The drains remain in place for 5 to 14 days. 18 Numbness and dysesthesia are more common when RF assistance is used, resulting from thermal coagulation causing demyelination of the sensory nerves. 41 Some patients (5%) do not regain sensation. 41 One of the most common injuries after a BodyTite treatment is damage to the medial antebrachial cutaneous nerve of the upper arm, sometimes causing permanent anesthesia. 41 Induration is common. 25 After thermal treatments, a prolonged thickness and brawny edema of the skin may require many months to resolve. 41 In 2020, a case of full-thickness burns, resulting in scars and major skin irregularities, was reported following a BodyTite-assisted liposuction treatment of the thighs in a 51-year-old woman. 56 The procedure was performed using a tumescent solution and a target temperature of 40°C. The author also encountered burns in 3 other patients.
Chia et al 33 recently published a study using a "secondgeneration" RF device and reported a significant decrease in complications, including burns. This modification, which was introduced in 2016, adds internal monitoring of temperature and its rate of rise to avoid dangerous temperature spikes. 33 The internal electrode cutoff temperature range is 50°C to 70°C, and the external electrode cutoff temperature range is 35°C to 43°C. 35 When the predetermined cutoff temperature is reached, RF power automatically switches off. 35 Without this modification, complications (ie, fibrous nodules and burns) 33,41 may occur before the operator is aware of the excessive heat buildup. 33,41 In many studies, it is not clear that proper institutional review board approval was obtained. 9,11,16,24,32,33,36,40 The Department of Health and Human Services mandates institutional review board approval for clinical studies in the United States. 57 Institutional review board approval is intended to protect patients by properly informing them of the risks of new procedures.

FDA 510(k) Clearance
The InMode BodyTite device received Food and Drug Administration (FDA) clearance in February 2016, based on its being substantially equivalent to an existing device, the ThermiGen Symphony RF System. 58 Clearance for this ThermiGen system was based on another device that was cleared because it too was judged to be similar to an existing (predicate) device. According to the FDA records, the earlier devices on which the InMode device was cleared were never actually approved. The indications are identical-use in dermatologic and general surgical procedures for electrocoagulation and hemostasis. The company, including its representatives, is not allowed to market the device for other indications. 58 The InMode Quick Reference Guide includes as an indication, "heating of fibrous septa and papillary dermis resulting in collagen contraction and skin tightening." Any "off label" clinical use that is not FDA-approved requires disclosure. No such disclosures appear in these publications. Inserting a heated probe under the skin of the breasts 36 or labia 32 to cause tissue necrosis are off-label applications. The thin mucosa and skin of the labia minora would seem too tight a space to accommodate a FaceTite probe. A true subcutaneous plane with adipose tissue may not even exist in these locations. Local numbness and dysesthesias would not be well tolerated.
Manufacturers are required to report adverse events to the FDA. 59 InMode consultants have reported "major" complications. 18,33 However, there is no record of these adverse events being reported to the FDA, according to the government website. 60

Comparison With Surgical Results
Radiofrequency is promoted to patients as a 3-dimensional shrink-wrapping of the "fibroseptal network." 22,24,33,35,37,53 When it was introduced, its advocates promised faster treatment, reduced tissue trauma, improved safety, uniform heating of the skin and the subcutaneous layer, and potential skin contraction. 9 A common theme is that advanced expensive technology is scarless, painless, offers a rapid recovery, and is a safer alternative to surgery. 42,53 These treatments may be marketed as 1-time procedures, with no surgery, performed in the office under local anesthesia, providing long-lasting results and minimal downtime. 53 Radiofrequency treatments are promoted to drive practice volume by recruiting patients who may ultimately return for excisional procedures. 53 The publication by Turer et al 39 includes a quantitative analysis of neck skin area. Most patients demonstrated a contraction of at least 20 mm 2 , and the average contraction was 71 mm 2 after a Thermi treatment. This is a modest difference. By comparison, the area of a US Forever postage stamp is about 400 mm 2 . 61 Patients treated with a traditional submental lipectomy, especially younger patients, often demonstrate excellent skin contraction (Fig. 6). It is well known that skin contraction can occur in patients without heating the internal tissues (Figs. 5-7).
A conceptual problem with topical RF treatment is that fat atrophy is not usually desirable in the face. In fact, most aging patients benefit from fat transfer, not fat removal. 62 A limitation of energy-based devices is its destructive effect on adipose cells. 9 Aspirated fat cannot be transferred to other areas of the body, breast, or face. 9 Platysmal bands cannot be treated using these devices and may be unmasked. Subplatysmal fat is best excised surgically. 53 Radiofrequency devices are frequently promoted as a "nonexcisional" alternative to a facelift, 14,25 even simulating the effect of a facelift. 37 Surgery is often described as invasive or excisional. Radiofrequency, unlike ultrasound, which was a previous energy-based treatment, does not specifically target fat. All tissues are coagulated, including vessels, lymphatics, nerves, and connective tissue, causing the tissue to condense. 15,35 There is no evidence for a more delicate controlled action like strings on the dermis. 40 The liquefied tissue resembles a milkshake as it is aspirated. 12 Subsurface RF treatments do require incisions, anesthesia, and frequently a general anesthetic. The procedures are not quick. Downtimes can be prolonged. Subsurface RF treatments are not inexpensive (Table 2). According to RealSelf.com, the average cost of a FaceTite treatment is $5100. BodyTite treatments cost $6650. By comparison, submental liposuction costs $3000. The average cost of liposuction is $6250. 52 An alternative is to offer a submental lipectomy (Fig. 6) or a limited-incision deep-plane facelift, which avoids a pulled-back appearance. 62 Surgical treatment avoids harm from burning and allows more precise control and dissection of tissues. Fat transfer is now part of the armamentarium of most facelift surgeons. 62 Subsurface RF treatments are surprisingly long and tedious. "Burn anxiety" is an issue. Lubricating ointment must be heavily FIGURE 6. A, B, This 37-year-old woman is seen before and 3 months after a submental lipectomy and secondary rhinoplasty performed by the author. The neck was treated using a submental incision, liposuction, direct resection of interplatysmal fat, and a medial platysmaplasty. Her profile is enhanced with a good skin response. applied. The loud warning bell signals are disquieting. There is no direct visualization of tissue planes. The tissue depth is inflated by the tumescent solution, obscuring landmarks. A submental lipectomy includes liposuction, direct excision of interplatysmal fat, and a corset platysmaplasty, all done using a single submental incision in 20 to 30 minutes by an experienced plastic surgeon (Fig. 6). The muscle repair treats platysmal bands, which cannot be managed with RF-assisted liposuction. 53 No dressings are needed. A chin strap is worn overnight. 62 Recovery is quick and discomfort is minimal. Comparisons favor this method (Table 3).
Similarly, excellent skin contraction of the abdomen may be achieved after liposuction without RF assistance (Fig. 7). RealSelf "Worth It" scores for surgical procedures are consistently higher (86%-99%) than RF treatments (44%-78%). 52 Chin liposuction and deep-plane facelifts score 91% and 99%, respectively (Table 2). According to a patient-reported outcome study, patient satisfaction after a subsuperficial musculoaponeurotic system facelift is 97%, and 94% of patients would recommend the treatment to someone else. 62 Patient satisfaction after traditional liposuction tends to be high, with about 90% of patients pleased with their result and 94% reporting that they would do it again. 63 Recovery is not difficult. Patients take 5.7 days off work, on average. 63 Drains are unnecessary. Seromas are rare. 64 The operating time for treatment of the abdomen and flanks is 30 to 60 minutes when performed under intravenous sedation. 64 Radiofrequency treatments take longer. 18 Retreatments are common. 17 Table 4 compares methods.
Cook et al 36 promote BodyTite as a breast lift alternative. To demonstrate, the authors compare before and after measurements. The procedure requires 30 to 45 minutes per side to perform. The cost is about the same as a mastopexy. Comparison of matched photographs (Fig. 2) reveals minimal benefit.

CONCLUSIONS
Little evidence supports improved efficacy or easier recovery after subcutaneous RF treatments compared with results that may be FIGURE 7. A, B, This 24-year-old woman is shown before and 6 months after lower body liposuction without RF assistance. A single treatment was performed by the author. Superwet infiltration was used. A total intravenous anesthetic was administered. The photographs are matched for size and orientation using the Canfield 7.4.1 Mirror imaging software. Measurements between landmarks on the abdomen-a pigmented lesion and a umbilical piercing-show a 9.4% linear skin contraction. A measurement on the left thigh between a skin lesion and a medial thigh stretch mark reveals an 11.6% linear skin contraction. Decreases in surface area are calculated as the square of linear changes. These reductions are 18.0% and 21.9%, respectively. obtained using traditional methods such as submental lipectomy and liposuction. Controlled studies are lacking. The treatments are not innocuous; complications are common. Investigator conflict of interest taints published studies. Plastic surgeons need to be aware of the limitations of this method and its regulatory status, before purchasing an expensive thermal device and offering RF treatments to patients. Scientific evaluation must take precedence over marketing to ensure that patients receive valid treatment recommendations.