Simulation-guided development of advanced PID control algorithm for skin cooling in radiofrequency lipolysis.

BACKGROUND: The clinical outcomes of bipolar radiofrequency (RF) lipolysis, a prevalent non-invasive fat reduction procedure, hinge on the delicate balance between effective lipolysis and patient safety, with skin overheating and subsequent tissue damage as primary concerns. OBJECTIVE: This study aimed to investigate a novel bipolar radiofrequency lipolysis technique, safeguarding the skin through an innovative PID temperature control algorithm. METHODS: Utilizing COMSOL Multiphysics simulation software, a two-dimensional fat and skin tissue model was established, simulating various PID temperature control schemes. The crux of the simulation involved a comparative analysis of different PID temperatures at 45 °C, 50 °C, and 55 °C and constant power strategies, assessing their implications on skin temperature. Concurrently, a custom bipolar radiofrequency lipolysis device was developed, with ex vivo experiments conducted using porcine tissue for empirical validation. RESULTS: The findings indicated that with PID settings of Kp = 7, Ki = 2, and Kd = 0, and skin temperature control at 45 °C or 50 °C, the innovative PID-based epidermal temperature control strategy successfully maintained the epidermal temperature within a safe range. This maintenance was achieved without compromising the effectiveness of RF lipolysis, significantly reducing the risk of thermal damage to the skin layers. CONCLUSION: Our research confirms the substantial practical utility of this advanced PID-based bipolar RF lipolysis technique in clinical aesthetic procedures, enhancing patient safety during adipose tissue ablation therapies.

Efficacy and safety of a novel combined 1060-nm and 635-nm laser device for non-invasive reduction of abdominal and submental fat.

The aim of this study was to evaluate the safety and efficacy of combined 1060-nm diode laser and 635-nm low-level laser therapy (LLLT) device for non-invasive reduction of the abdominal and submental fat. Forty-two healthy subjects received single laser treatment on both the abdomen and submental area. Ultrasound images measuring the thickness of abdominal and submental fat were taken at baseline, follow-up at 4, 8, and 12 weeks after treatment. Waist circumference and body weight were also measured at all visits. Adverse events were recorded at all visits. Subjects completed a satisfaction questionnaire at the end of the trial. Twelve weeks after a single treatment with the investigational device, ultrasound images showed statistically significant (P < 0.0001) reductions in abdominal and submental fat by 18.62 and 26.4%, respectively. In addition, significant (P < 0.0001) reduction in waist circumference was observed. Ninety-six percent of subjects rated that they were satisfied. Noted side effects were transient mild to moderate tenderness which subsided within 1 to 3 weeks. No serious treatment-related adverse events were reported. The dual wavelength device combining 1060-nm diode laser with 635-nm LLLT was safe and effective for non-invasive reduction of both abdominal and submental fat.

Improving Low-Density Fat by Condensing Cellular and Collagen Content through a Mechanical Process: Basic Research and Clinical Applications.

BACKGROUND: Large-volume fat grafting results in high absorption and complication rates. Low-density fat includes small numbers of viable cells and considerable oil, resulting in nodules and oil cysts. This study evaluated a strategy for large-volume fat grafting using a mechanical process to condense low-density fat and transplanting it with high-density fat. METHODS: Low-density fat, defined as the upper half of centrifuged lipoaspirates, was emulsified by intersyringe shifting and centrifuged to obtain condensed low-density fat. Fresh condensed low-density fat was analyzed by counting cells in the stromal vascular fraction, and by electron scanning and Western blotting. The retention rate and histologic changes of the product were analyzed using a fat grafting model in nude mice. Transplantation with a combination of condensed low-density fat and high-density fat was tested in patients undergoing breast reconstruction and breast augmentation. RESULTS: The condensed low-density fat derived from low-density fat contained a large number of stromal vascular fraction cells and collagens, comparable to that of high-density fat and much higher than in low-density fat and Coleman fat. Retention rates 12 weeks after transplantation were higher for condensed low-density fat (55.0 ± 7.5 percent) than for low-density fat (31.1 ± 5.7 percent) and Coleman fat (41.1 ± 6.8 percent), with condensed low-density fat having fewer oil cysts and lower macrophage infiltration. Patients grafted with combined condensed low-density fat and high-density fat showed good long-term volume retention. CONCLUSIONS: Using mechanical methods to condense low-density fat to a level comparable to that of high-density fat is a practical method of improving fat graft retention and avoiding severe complications. This new strategy may improve the quality of lipoaspirates for patients requiring large-volume augmentation.

High Volume Liposuction in Tumescence Anesthesia in Lipedema Patients: A Retrospective Analysis.

BACKGROUND: Lipedema is a chronic, progressive disease that occurs almost exclusively in women and leads to pathological, painful fat growths at the extremities. Only symptomatic therapy can be offered since the etiology of the disease has not yet been clarified. Liposuction in tumescent anesthesia has established itself as a surgical treatment method of choice. The complication rate associated with the procedure and the pharmacological course and safety of treatment in patients with lipedema has not yet been sufficiently studied. The aim of the study was to broaden the evidence on the safety of ambulatory high-volume liposuction in tumescent anesthesia in lipedema patients. Influencing factors of patients (weight, fat content, comorbidities) or the process technique (drug administration, volume of aspirates) should be investigated on the safety and risks of tumescent anesthesia. This was a retrospective data analysis in which data from 27 patients (40 liposuction procedures) treated at the Sandhofer and Barsch lipedema center between 2016 and 2018 were evaluated. The liposuctions were carried out in tumescent anesthesia and using a Power-Assisted Liposuction system. Clinical examinations and regular blood samples were carried out before the procedure, intra- and postoperatively. The procedures lasted an average of 118 minutes and an average of 6111 ml of aspirate was removed. For tumescent anesthesia, patients were given an average lidocaine dose of 34.23 mg/kg body weight and an epinephrine dose of 0.11 mg/kg body weight. No relevant complications associated with drug side effects, hypovolemia or hypervolemia or blood loss were detected. Liposuction under high volume tumescent anesthesia for the treatment of lipedema patients is, even for major intervention, a safe procedure. J Drugs Dermatol. 2021;20(3):326-334. doi:10.36849/JDD.5828.

Evaluating, Purchasing, and Incorporating High-Tech Equipment into a Facial Plastic Surgery Practice.

In this article the authors discuss and analyze technological devices also known as energy-based devices and their use in skin rejuvenation, facial contouring, skin tightening, and other applications in facial plastic surgery. Energy has been applied in some form to tissue since the beginning of recorded history. The practice of applying heat to tissue with the use of cauters was used for thousands of years as an invaluable method of controlling hemorrhage. Continuous improvement of methods for using the beneficial effects of heat on tissue eventually led to the development of the basic concepts of electrosurgery we know today.

Liposuction: Concepts, safety, and techniques in body-contouring surgery.

Liposuction is the second most commonly performed cosmetic surgery in the United States and the most common surgical procedure in patients between the ages of 35 and 64; practitioners of medicine and surgery will undoubtedly encounter these patients in their practice. This brief review discusses the role of liposuction and fat transfer in aesthetic and reconstructive surgery, as well as key considerations, indications, and safety concerns.

Comparative technical analysis of lipoaspirate mechanical processing devices.

Fat grafting is a well-established procedure in reconstructive, aesthetic, and regenerative medicine, in particular due to the presence in the adipose tissue of a high concentration of mesenchymal stem cells. The need to reduce fat processing times, for an immediate clinical use and regulatory restrictions on the degree of manipulation of human tissues, has led to the development of numerous devices for the mechanical, nonenzymatic processing of adipose tissue. The aim of this study is to describe the state of the art of mechanical devices used for fat processing, performing a technical analysis of the currently commercially available devices. This should facilitate the development of new devices that improve therapeutic results.

Adipose-derived stem/progenitor cells from lipoaspirates: A comparison between the Lipivage200-5 liposuction system and the Body-Jet liposuction system.

BACKGROUND: Adipose-derived stem/progenitor cells (ADSPCs) are under investigation in many clinical applications for their regenerative potential in a variety of autoimmune, degenerative, and inflammatory diseases. Adipose tissue, which is mainly harvested by manual liposuction, is the main source of these ADSPCs. OBJECTIVE: In the past years, a variety of different liposuction devices have been commercialized. To ensure a high quality of obtained ADSPCs, it is crucial to show the advantages and disadvantages of frequently used liposuction methods. For this reason, the objective of this study was to compare ADSPCs harvested by either the suction-assisted LipiVage200-5 or the water-assisted Body-Jet system. METHODS: The proliferation potential of ADSPCs, harvested from 20 patients, was assessed by cumulative population doublings (cumPD), population doubling time (PDT), colony-forming units (CFU), and cell metabolism assays. To prove the multipotency of the primary isolated cells, ADSPCs were induced to differentiate into adipogenic, osteogenic, and chondrogenic lineages. RESULTS: Our data show a significantly higher cumPD, as well as a significantly lower PDT for cells obtained by the Body-Jet system. No significant differences were found regarding the CFU efficiency and the cell metabolism. Furthermore, we showed that the adipogenic, osteogenic, and chondrogenic potential of ADSPCs is similar in both groups. DISCUSSION/CONCLUSION: In our study, we provide evidence that the cell characteristics and the functional properties of ADSPCs isolated after liposuction with different techniques are largely similar. However, we observed a significantly higher cumPD and a slightly higher adipogenic potential in cells isolated after liposuction with the Body-Jet system. Different cannula sizes and sheer stresses in the used methods might play a role here.

Vacuum-assisted minimally invasive surgery-An innovative method for the operative treatment of gynecomastia.

BACKGROUND: Gynecomastia is the most common benign enlargement of the mammary gland and adipose tissue in males. Because a feminine-looking chest contour can bring severe psychologic burden to patients, subcutaneous mastectomy has become the standard treatment for this condition. Conventional open surgery causes conspicuous scarring that may affect the appearance of the breast. We provide a novel surgical operative for the treatment of gynecomastia. METHOD: With approval from our institutional ethics committee and written informed consent, 22 patients with 33 abnormally hyperplastic breasts were enrolled at The First Affiliated Hospital with Nanjing Medical University between June 2016 and September 2018. Vacuum-assisted minimally invasive surgery was performed under general anesthesia. Patients were followed up with physical examination and ultrasonography. RESULT: Vacuum-assisted minimally invasive mastectomy was performed successfully in all cases, with no residual glands or adipose tissue observed on ultrasonography. The operation had a mean duration of 73.5 minutes per side, ranging from 40 to 102 minutes. An average of 320 specimens were excised from each side with mean blood loss of 34 mL. Of these 33 operative sides, 2 complications occurred, but satisfactory chest contour was attained eventually in all patients. All patients were satisfied with their cosmetic outcome, graded as excellent by 22 patients (100%). Redundant skin was observed in 1 patient at 1 month postoperatively, whose breast, defined as graded III, was the largest before operation. CONCLUSION: Vacuum-assisted, minimally invasive mastectomy is a feasible approach for the treatment of gynecomastia with acceptable complications.

Numerical Study of Hyper-Thermic Laser Lipolysis With 1,064 nm Nd:YAG Laser in Human Subjects.

BACKGROUND AND OBJECTIVES: The aim of this study was to develop a numerical model for hyperthermic laser lipolysis in human subjects to improve understanding of the procedure and find optimal therapeutic parameters. STUDY DESIGN/MATERIALS AND METHODS: A numerical model of hyperthermic laser lipolysis (HTLL) on human subjects was developed that is based on light and heat transport, including the effects of blood perfusion and forced air cooling. Tissue damage was evaluated using the Arrhenius model. Three irradiation scenarios were considered: single skin area irradiation without and with forced air cooling, and sequential heating of four adjacent skin areas in a cyclical manner. An evaluation of the numerical model was made by comparing the recorded skin surface temperature evolution during an experimental HTLL procedure performed on the abdomen of ten human volunteers using a 1,064 nm Nd:YAG laser irradiation. RESULTS: A good agreement was obtained between the simulated skin surface temperatures and that as measured during the HTLL procedure. The temperature difference between the simulations and experiments was in the range of 0.2-0.4°C. The model parameters, which were fitted to the experiment were the perfusion parameter (0.36-0.79 and 0.18-0.49 kg/m 3 ·s for dermis and subcutis) and the subcutaneous tissue absorption coefficient (0.17-0.21 cm -1 ). By using the developed HTLL model and the determined parameters, temperature depth distributions and the resulting thermal injury to adipocytes were simulated under different treatment conditions. Optimal ranges of the HTTL treatment parameters were determined for different skin types, damaging adipocytes while preserving skin cells. The target subcutaneous temperatures were in the range of 43-47°C, which has been found to lead to programmed adipocyte death. The optimal treatment parameters were further used to define a range of recommended protocols for safe and effective multiarea cycled HTLL treatment of large body surfaces. Specifically, for the set of chosen optimal treatment parameters (4-5 treatment cycles, 1.2 W/cm 2 radiant exposure, and 60-130 W/cm 2 forced air heat-transfer coefficient) the threshold surface temperature during irradiation was found to be in the range of 31-38°C, depending on the skin type and heat-transfer coefficient. CONCLUSIONS: The developed numerical model allows for the calculation of the temperature distribution and the resulting injury to adipocyte cells within deeper lying fatty tissues under different clinical treatment conditions. It is demonstrated that by measuring the temporal evolution of the skin surface temperature and by stopping the laser irradiation at predefined skin surface threshold temperatures, it may be possible to monitor and control the effects of the HTLL procedure deeper within the tissue. As such, the model provides a better insight into the HTLL, and may become a tool for defining the range of safe and effective HTLL treatment protocols for patients with different skin types. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Cryolipolysis for Noninvasive Contouring of the Periumbilical Abdomen With a Nonvacuum Conformable-Surface Applicator.

BACKGROUND: Although most cryolipolysis treatments are performed with vacuum applicators, some patients may have areas of fibrous, nonpinchable fat or find vacuum suction to be uncomfortable. OBJECTIVE: This study evaluates a nonvacuum conformable-surface applicator for cryolipolysis of the periumbilical abdomen. METHODS/MATERIALS: Twenty subjects with periumbilical subcutaneous fat were treated with a nonvacuum cryolipolysis applicator in this prospective, single-center, open-label clinical trial. Each subject underwent a single treatment cycle with an optional second treatment 10 weeks later. Efficacy was evaluated by blinded review of digital photographs. Subject satisfaction was assessed at 10-week follow-up. RESULTS: Twenty subjects completed one treatment, of which 6 underwent the optional retreatment. Independent review demonstrated 77% correct identification of baseline photographs after one treatment, which improved to 100% after a second treatment. Patient questionnaires after one treatment revealed 50% satisfaction, with 60% willing to recommend the procedure and 60% reporting visible fat reduction. After second treatment, however, 100% were satisfied, 83% were willing to recommend, and 100% reported visible fat reduction. CONCLUSION: Cryolipolysis with a nonvacuum conformable-surface applicator is safe, effective, and well tolerated for noninvasive reduction of fibrous periumbilical abdominal fat. Efficacy and subject satisfaction is significantly greater with 2 treatments than with a single session.

Simultaneous flap thinning with ultrasound-assisted liposuction during free flap surgery: Preliminary results.

BACKGROUND: Ultrasound-assisted liposuction (UAL) has been previously used for postoperative flap thinning. Although it had been reported that UAL causes less damage to the vessels, the simultaneous use of UAL with free flap reconstruction has not been reported. The aim of this report was to determine the results and the complication rates of simultaneous use of UAL with free flap reconstruction. PATIENTS AND METHODS: Twelve patients who underwent simultaneous flap thinning with UAL during free anterolateral thigh flap surgery between 2014 and 2016 were included in this prospective study. The mean age of the patients was 46.7 (ranging 10-76) years. The mean body mass index of the patients was 26.81 (ranging 25.2-29.8). Flaps were thinned with UAL before harvesting. The mean flap thicknesses were measured using a metal ruler before and after the UAL procedure. Biopsies were performed lateral to the center of the flaps, after completion of the UAL procedure. Vascular and collagen structures were histopathologically examined. The Likert scale, which evaluates the general appearance, shape, color, and texture, was used to assess the aesthetic results of the UAL procedure. RESULTS: The average flap size was 13 × 9 cm. The mean pedicle length was 8.3 (ranging 7-10) cm. The mean flap thickness was 23 (ranging 19-27) mm and decreased to a mean of 8.1 (ranging 5-11) mm. Wound dehiscence and partial skin necrosis was observed in 2 patients (2/12, 16.66%). None of the patients had total flap necrosis. Vascular and collagen structures of the biopsied samples were normal. Patients were followed for an average of 13 months post UAL. The mean Likert score was 17.1 (ranging 15-19). CONCLUSIONS: Flap thinning with UAL can be safely performed during the initial free flap reconstruction operation.

Minimally invasive approaches to axillary osmidrosis treatment: A comparison between superficial liposuction with automatic shaver curettage, subcutaneous laser treatment, and microwave-based therapy with a modified technique.

BACKGROUND: Minimally invasive techniques, including superficial liposuction with automatic shaver curettage (LC), subcutaneous laser treatment, and microwave-based therapy have been developed to treat osmidrosis. Few studies have compared these three techniques in relation to clinical efficacy, life quality improvement, and downtime. AIMS: We aim to evaluate clinical results and life quality improvement, in addition to downtime and complications, between these three techniques. PATIENTS/METHODS: Clinical records of patients treated with these three minimally invasive techniques for axillary osmidrosis were retrospectively reviewed. Hyperhidrosis disease severity scale, Dermatology Life of Quality Index, clinical improvement, complication, and recurrence were assessed. RESULTS: Among 403 patients, 168 received microwave-based therapy, 119 received subcutaneous laser treatment, and 116 received LC. All treatments showed significant improvements (P < 0.001) in HDSS, DLQI and clinical result after 3 and 12 months comparing to the baseline. But the improvements of subcutaneous laser were significantly inferior to microwave-base therapy and LC. Patients who received LC had a significantly longer downtime (P < 0.001) than those who received other treatments. The recurrence rate was significantly higher in the subcutaneous laser treatment group, and the microwave-based therapy group exhibited a longer recurrence duration (P < 0.001). LC group presented higher complication rate than other treatments. CONCLUSION: Comparing to other treatments, microwave-based therapy was effective in treating osmidrosis with minimal downtime, recurrence, and complications. It could be a durable and effective therapeutic modality for osmidrosis and is less operator-dependent. It may be considered as a first-line treatment for axillary osmidrosis.

Lipectomizing Mice for Applications in Metabolism.

The obesity epidemic is a critical public health problem closely associated with the development of metabolic disease. In obesity there is excess white adipose tissue, a dynamic tissue that has many biological functions. Specifically visceral adipose tissue (VAT) is an active endocrine organ producing hormones that control systemic metabolism. VAT accumulates immune cells that produce cytokines that drive chronic inflammation and promote insulin resistance. VAT can be surgically removed in experimental animals (lipectomy) to explore mechanisms by which VAT participates in metabolic, endocrine, and immunological functions. This chapter describes the technical protocol for efficient and successful removal of the gonadal fat pads in mice.

Double stacking cryolipolysis treatment of the abdominal fat with use of a novel contoured applicator.

Background: Cryolipolysis is a noninvasive method for the selective reduction of subcutaneous fat. The abdomen and flank area are most commonly treated sites and now the treatment efficacy became the important issue. Objectives: To evaluate the effectiveness and safety of double stacking cryolipolysis treatment with the novel contoured applicator for abdominal fat reduction. Materials and methods: 12 healthy Korean were treated using cryolipolysis contact device. The device was applied on participant's left lower abdomen. Performance was held for 35 minutes and immediately repeated the second performance. The right abdomen was left untreated. Participants were examined with high resolution ultrasound and the depth of subcutaneous fat layer was measured initially and 8 weeks after the sessions. Any adverse events were assessed during the entire study period. Results: The subjective reduction of abdominal fat was noted in most participants. No serious adverse events was reported. Reduction of subcutaneous fat layer depth was confirmed in high resolution ultrasound after 8 weeks of treatment. Conclusion: The results of this study indicate that abdominal fat can be reduced effectively by the novel cryolipolysis applicator. With subjective satisfaction of participants our study shows that double stacking treatment appears safe and well tolerated with enhanced treatment outcomes.

The Architecture of Fat Grafting II: Impact of Cannula Diameter.

BACKGROUND: Fat grafting has emerged as the treatment of choice for soft-tissue augmentation and reconstruction. Variability of volume retention remains the greatest challenge for this technique, often requiring multiple operations to achieve the desired volume. Graft that is placed greater than 2 mm from the recipient bed will undergo necrosis. Improved understanding of the architecture of fat within the recipient bed is paramount to improving outcomes. The impact of cannula diameter on graft architecture is unknown. METHODS: Fat was harvested by liposuction and stained with methylene blue. Stained fat was grafted into 4 × 2 × 1-cm sections of excised abdominal tissue with 12-, 14-, 16-, and 19-gauge Coleman cannulas at three different volumes: 0.1, 0.5, and 1.0 cc. Each tissue block was sectioned for stained graft visualization. The diameter of each deposit and percentage with a radius greater than 2 mm were recorded. RESULTS: With an injection volume of 0.1 cc, no fat deposits had a radius greater than 2 mm, regardless of cannula size. A graft volume of 0.5 cc created globules greater than 2 mm with larger cannulas (0 percent with 19-gauge, 2.9 percent with 16-gauge, 6.1 percent with 14-gauge, and 4.3 percent with 12-gauge). Injecting 1.0 cc resulted in a significant increase in the percentage of fat parcels expected to undergo central necrosis (16 percent with 19-gauge, 21 percent with 16-gauge, 26 percent with 14-gauge, and 44 percent with 12-gauge). CONCLUSIONS: Injection cannulas of 14-gauge or larger are more likely to create deposits with dimensions that may be susceptible to central necrosis when injecting 1.0 cc per pass. Smaller cannula sizes or lower volumes per pass should be considered. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

In vitro investigation into the forces involved during lipofilling.

Breast augmentation using implants is the most common aesthetic and reconstructive breast surgical procedure. Complications such as implant rupture maybe related to surgical technique and damage to the implant. Autologous fat transfer (lipofilling) using metallic cannulae has become a standard adjunctive, yet there is little evidence on lipofilling safety in the presence of implants. The aims of this study are to verify the effects of different cannulae and to quantify the forces applied by surgeons during lipofilling. Silicone gel-filled textured implants (200 mL), mounted on a specially constructed mould were ruptured with two different cannulae: type A (hole at tip: sharp) and type B (hole away from tip: blunt), driven at three speeds (10, 100 and 1000 mm/min), and the force at rupture was recorded. In addition, the maximum 10 forces over a 30-s period applied by 11 plastic surgeons against a breast implant in an in vitro environment were recorded using a load cell attached to a type-A cannula. Statistical analysis of comparative results was performed using t-tests, with p < 0.05 considered significant. Results showed that the implant ruptured at forces up to 25% lower when cannula A was used compared to cannula B. This supports current technique in lipofilling in the use of a blunt tipped cannula. There was a significant difference between some displacement rates only, due to the viscoelastic nature of the material. The tactile force that surgeons use during lipofilling was modelled in vitro and showed a range of maximum forces between 0.23 and 16.8 N, with a mean maximum value of 6.9 N. Limitation of this study is that it may not reflect in vivo behaviour of breast implants. More studies are needed to confirm the safety of breast lipofilling in the presence of implants using these data as a starting point.