Three‐dimensional analysis for measuring volumetric changes after a noninvasive treatment performed with a new system delivering microwave energy for unwanted abdominal fat reduction

A growing demand for aesthetic treatments for localized abdominal unwanted fat has developed as a healthy lifestyle is not always able to improve abdomen appearance.


| INTRODUC TI ON
Localized abdominal subdermal adiposities are among the most common aesthetic problems in both sexes, with an increasing demand for body remodeling treatments. 1 Lifestyle has a significant role in limiting abdominal fat.A regular physical activity and correct diet are indispensable. 2Nevertheless, aesthetic improvement in the abdomen appearance is not always achieved through a healthy lifestyle.4][5][6][7] Although surgery is still the first choice with regard to the results obtained, the market trend is increasingly moving towards minimally or noninvasive procedures. 1 Among the panorama of new technologies, recently microwaves (MWs) has shown a promising role in body sculpting [8][9][10] improving the abdominal aspect, reducing the subcutaneous adipose tissue while preserving and/or improving skin tightening, through a noninvasive system, avoiding side effects and the necessity to extended patient's recovery time.
This study brings to evaluate an innovative MW technology, recently developed to treat localized adiposities, cellulite, and skin laxity, applied to the abdominal area.Using a dedicated software for 3D imaging analysis the purpose of this work is to assess the abdominal volume and circumference changes in treated patients.The current study had as its main objective to quantify the effects of treatments on abdominal tissues, and to provide hypotheses for future research on this technology.The study outcomes are expected to suggest that MW technology can be used in a safe and effective manner for noninvasive body-shaping treatments.

| Patient selection and study device
This was a nonrandomized observational study of subjects seeking treatment for abdominal fat reduction.Data collected in the medical center Laserplast SrL STP in Milan, Italy, between October 2020 and March 2022 were analyzed.
A total of 20 patients (17 female and 3 male) aged 31 to 56 years (mean age 48.7) with an average body mass index (BMI) of 27.2 ± 2.7 kg/m 2 who were dissatisfied with the appearance of their abdomen were treated in the abdominal area with ONDA PLUS system (DEKA M.E.L.A, Florence, Italy).This innovative medical device utilizes MWs to offer localized adiposity, skin laxity, and cellulite management.MWs are electromagnetic waves (frequency 1-300 GHz).The study device, delivering 2.45 GHz MW radiation, it is able to generate controlled and localized heat absorbed by fat, through a biophysical process namely "dielectric heating." 11It has been discovery that at this frequency, skin tissue allows a greater passage of the energy, making it free to focus its action totally on the subcutaneous adipose layer in a specific way, directing all the energy to the selected target.Different from existing technologies, this treatment modality ensures that the superficial layers of the dermis are preserved from unwanted heating and remain cold.Moreover, an effective contact cooling system built inside the handpieces is implemented to further preserve the skin superficial layers from overheating.
All patients completed all scheduled cycle of treatments and presented for the follow-up visits (N = 20).
All study procedures were conducted according to Declaration of Helsinki and a signed written consent form was released by all patients.
Study demographics characteristics of subjects at baseline are summarized in Table 1.
Inclusion criteria are healthy adult of both sexes with an abdominal skinfold thicker than 2 cm (the subdermal fat layer must be at least 1 cm thick) and thinner than 5.5 cm.The skinfold thickness examinations were assessed with the use of a plicometer.All patients did not receive any kind of surgical or dermatologic treatments in order to reduce body fat.All participants did not change their dietary regime or exercise routine, maintained their current weight, and no supplemental fat-reducing elements were taken.
Exclusion criteria were as follows: BMI >30 kg/m 2 ; any prior intervention(s) to treat abdominal fat, including RF, lasers, cryolipolysis, liposuction, and surgery within 12 months; skin disorders in and/ or close the treatment area; patients with unrealistic expectations; patients with heart problems, tumors or those who are immunosuppressed; patients with hypertriglyceridemia and hypercholesterolemia, diabetes, blood pressure alteration, autoimmune pathologies, and ongoing systemic diseases; pregnant or lactating patients.
When using anticoagulants, antiaggregants, anti-inflammatory drugs with steroids, retinoids, and antioxidants the therapy was suspended a week before the treatment.
In the case of patients previously treated for laparocele with a surgical positioning of a mesh made by alloplastic material, an ultrasound examination was carried out to assess that the distance from the skin surface in the treatment area was greater than 2 cm and that the mesh was positioned under the rectus abdominis muscles.

| Pretreatment protocol
All patients were instructed to suspend the use of moisturizing and softening creams of the areas to be treated at least 1 week before TA B L E 1 Demographics and baseline characteristics of study subjects.The abdominal volume refers to a portion of the bust between −2.5 cm and +2.5 cm from the plane where the circumference is measured.In practice, it is a truncated cone with a height of 5 cm centered, in height, on the abdominal circumference measured by the software.Validation studies of this system showed that 3DSM is a useful method for the assessment of the anatomical morphology due to its high accuracy and reproducibility, [12][13][14] also for the specific abdominal area. 15,16e presence of biases that could alter the results were considered.

Classification
With reference to possible measurement bias, the use of a single previously calibrated measurement instrument was planned, and it was ensured that the participants positioning in front of the 3DFM camera system would be standardized; Selection bias could not be controlled.
Any possible side effects and adverse events including numbness, itching, heat, swelling, tenderness, burns, redness, hardness, fat/skin tissue necrosis, bruising, nodules, blisters, skin irregularities, skin asymmetry (which could occur due to an improper or excessive energy setting or an incorrect assessment of the adipose tissue) were assessed during and after 24 hours of treatment sessions through the telephone contact of each patient.
A 10-point Numerical Rating Scale (NRS) was selected in order to assess patient's pain. 17The NRS scores are classified as follows: no pain: 0, mild: 1-3, moderate: 4-6, severe: 7-10.The NRS was assigned to each patient after the first session.
When subjects returned to clinic at 3MFU each patient was asked if he/she was interested in repeating the treatment in another body area.The question was asked to assess the patient's degree of satisfaction (satisfaction questionnaire).

| RE SULTS
3MFU after the last treatment, both abdominal circumference and volume examined, according to the study protocol, were significantly reduced (p < 0.001).All values are shown in the at baseline to 80.8 ± 8.2 cm and 1728.9 ± 490.9 cm 3 (p < 0.001) at 3MFU after the last treatment, as shown in the Figures 1 and 2. The improvement of abdominal appearance is clearly reported by the photographic assessment, as shown in Figures 3-6.
After the first session NRS pain score was recorded; the mean value was 0.5 ± 0.5 and the majority of patients denied any discomfort during and after treatment.
No patient experienced adverse effects assessed in the study during the entire treatment period.
Finally, from the analysis of the satisfaction questionnaire completed by all patients at 3MFU, it emerged that 90% of them would like to have a further treatment with the same system in another body area, confirming with this data a high degree of satisfaction for the treatment and achieved results.According to the literature, an in vitro 80% loss of fat cells can be achieved by increasing the to 50°C degrees. 18 previously mentioned in the introduction section, many Concerning this technology, prior studies hypothesized that microwaves could directly act on adipose tissue, sparing the dermoepidermal layers, leading to a macrophage-mediated adipocytes lysis cells heating. 23e high absorption of MW in the deep subcutaneous adipose tissue is due to its dielectric properties.

| DISCUSS ION
The thermal energy produced by this process promotes the adipocytes heating without affecting the dermo-epidermal layers.
[25]4 MWs technology appears to generate an irreversible adipocyte cytoplasmic and membrane damage. 8tivated macrophages are responsible for the removal of adipocytes with consequent of subcutaneous adipose tissue and circumference reduction, as reported in the current research.F I G U R E 2 Average abdominal circumference in cm 3 at baseline and at 3MFU after the last session with the microwave system.

F I G U R E 3 Representative case
showing clinical improvement and morphological changes of abdominal appearance before and at 3MFU after the last treatment session.
F I G U R E 1 Average abdominal circumference in cm at baseline and at 3MFU after the last session with the microwave system.
To understand well how the action of these MWs can act effectively in the subcutaneous fat layer, it is important to underline that at the frequency of 2.45 GHz, the skin can be considered as "transparent."This means that the energy passes through the dermalepidermal layers without substantially any thermal interaction, until it reaches the fat where it is then absorbed by raising the temperature of the adipocytes.In fact, from physics, skin behaves differently when submitted to different frequencies: Skin allows the passage of energy with high frequencies (as MWs), but it does not allow it anymore when the frequency of the same energy gets lower (as common RF used in for body contouring).Thus, frequency discriminates the skin passage properties. 25 lower frequencies there is a greater skin resistance which corresponds to a greater absorption of energy; therefore, these MW activating fibroblasts and the consequent skin texture improvement. 9On these bases it was found that MWs can also improve cellulite. 8e study findings demonstrate the promising role of MWs in treating localized abdominal subcutaneous adiposities and skin laxity.With the use of three-dimensional imaging analysis, investigators objectively and quantitatively demonstrated the efficacy of a new system delivering microwaves energy for the reduction of abdominal volume correlated to a subdermal fat reduction while preserving/improving skin tightening.Our findings showed a significant reduction of abdominal circumference and volume correlated to the localized subcutaneous fat reduction in that area and a recovery of the normal elastic tension of skin collagen resulting in a skin laxity improvement in all treated patients.The noninvasive procedure adopted in this study, in addition to its extreme tolerability and absence of side effects and complications, might offer a new, interesting alternative to traditional lipoplasty.
The treatment was well tolerated.Majority of patients did not experience any discomfort.Patient satisfaction grades were consistent with clinical improvement levels and 90% of patients said they were interested in repeating the same treatment in other areas of the body.

CO N FLI C T O F I NTER E S T S TATEM ENT
I.F. is employed at El.En.Group.The other authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are available from the corresponding author (I.F) upon reasonable request.

E TH I C A L S TATEM ENT
All study procedures were conducted according to Declaration of Helsinki.The authors confirm that the ethical review committee approval is not necessary as the study device is an already CE-marked device.

2 . 3 |
the high degree of absorption of MWs by water; this avoids having a greater MWs absorption in skin superficial layers allowing, at the same time, a better penetration of MWs.A thin layer of pure Vaseline oil was spread over the entire area before the treatment to ensure correct contact of the handpiece with the skin and greater fluidity of movements.Study protocol and assessments All subjects received 4 treatments, 4 weeks apart, For the treatment of the abdomen the Deep handpiece was used because it allows to reach better abdominal subdermal fat.Indeed, the deep handpiece leads to the largest and deepest heating, resulting in a controlled hyperthermia, which causes a molecular oscillation on the adipocytes and dissolves the deeper collagen fibers causing lipolysis of the fat cells and the remodeling of the collagen fibers through the stimulation of fibroblasts.The area to be treated was divided into two adjacent squares 15 × 15 cm 2 .Before starting with the treatment, the skinfold was measured.The starting power has been set at 150 W. The mean dose delivered for every square area was 150 000 J. The typical treatment time, for each square, was approximately 15 min.Patient's abdominal volume and circumference evaluation was performed at baseline and at 3 months follow-up (3MFU) using the Vectra XT 3D imaging system (Canfield Scientific, Inc, USA).The patient was kept in an upright position holding the breath at maximum inspiration.A mathematical surface-correspondence algorithm was used to acquire the followup 3D image by a trained and certified technician to precisely match the position and orientation of the baseline image.The Vectra threedimensional stereo photogrammetry (3DSM) camera system consists of six cameras positioned in a triangulated configuration with a capture time of 3.5 ms, the system is able to capture 3D images in 180° thanks to the variety of angles.Abdominal circumference and volume are calculated using preinstalled VECTRA analysis module software.
therapeutic options have been developed (such as noninvasive energy-based devices, topical treatments, and minimally invasive interventions) in order to overcome this condition.RF-generating oscillating magnetic fields which move electrically charged particles, produces heat in the tissues: this heat directed to the subcutaneous layer is presumably absorbed by the adipocytes until it induces the breakdown of fat cells through the lysis of the membrane. 19,20RF also favors fat thickness/ accumulation decrease in adipocytes. 21By raising the temperature of tissues, a denaturation of the old collagen and a consequent remodeling and generation of new collagen are stimulated.Both RF waves and MWs represent two electromagnetic radiation mode with operating frequencies which range from 30 to 300 MHz and 300 MHz to 300 GHz, respectively, 22 even if in some cases MWs are considered a sub-class of radio waves.It was well established that MW technology is a popular modern society technology and it already being used for medical applications.This study aimed to evaluate a new noninvasive technology involves the use of MW electromagnetic waves at 2.45 GHz for reducing abdominal fat improving skin laxity.

( 2 .
45 GHz = very high frequency) are able to cross the skin without generating an important and harmful heating, directly hitting the subcutaneous adipose tissue.Moreover, in the study of Yang et al 1979 26 authors report exactly that the fastest heating within the musculature occurs at 915 MHz with the maximum tissue temperature located only 1 cm from the skin surface.When a frequency of 2450 MHz is used, the value of microwaves as a muscular heating agent is diminished.The maximum temperature is observed in the subcutaneous skin layer with a distinct minimum temperature in the fat layer.The value of using shortwave and microwave modalities as a deep heating agent is diminished by an increase in the thickness of the subcutaneous fat layer.In previous studies, authors who used this MWs technology observed a positive change in the skin tone and texture of their patients.They suppose that this modification was due to the MWs action on collagen septa.Interlobular collagen fibers in the septa were reduced and fragmented thanks to the controlled hyperthermic process generated by the MWs activity. 27This contributes to subcutaneous tissue remodeling.In other words, MWs directly heat collagen septa, causing deeper collagen fibers dissolution, F I G U R E 4 Representative case showing clinical improvement and morphological changes of abdominal appearance before and at 3MFU after the last treatment session.F I G U R E 5 Representative case showing clinical improvement and morphological changes of abdominal appearance before and at 3MFU after the last treatment session.
Study limitations are represented by lack of proper control groups, small sample size and lack of extended follow-up evaluations to see the long-term beneficial effects of the subject device on subcutaneous fat reduction of the abdomen.5 | CON CLUS IONSIn this study, with the use of three-dimensional imaging techniques, the efficacy of a new system delivering microwaves energy for the reduction of abdominal volume correlated to a subdermal fat reduction while preserving and improving skin tightening, was quantitatively and objectively demonstrated.AUTH O R CO NTR I B UTI O N SM.T.C, P.B, and V.P performed the research and contributed substantially to the study design, interpretation, and data acquisition/ analysis; I.F contributed to the manuscript writing.All authors were involved in the drafting and revision of the manuscript and given final approval of the version to be published.Each author has agreed to be responsible for all aspects of the job to ensure that issues relating to the accuracy or integrity of any part of the job are properly investigated and resolved.

F I G U R E 6
Representative caseshowing clinical improvement and morphological changes of abdominal appearance before and at 3MFU after the last treatment session.

Table 2 .
3atacollected from the 3DSM camera system show that the average circumference and volume reduction were, respectively, 4.4 ± 2.0 cm and 221.7 ± 177.2 cm 3 .Both abdominal circumference and volume passed, respectively, from 85.2 ± 8.1 cm and 1950.6 ± 471.0 cm3