Author: Mark Jewell Affiliation: Oregon Health Science University, Portland, Oregon, USA
Noninvasive procedures that utilize high-intensity-focused ultrasound (HIFU) for the percutaneous ablation of targeted tissues is increasingly being used for the management of an array of oncological and nononcological conditions and has been investigated for new uses such as noninvasive subcutaneous adipose tissue ablation. Once adipocytes have been ablated with HIFU, macrophages are attracted to the area to engulf and transport the lipids and cellular debris. This removal results in an overall reduction in local adipose tissue volume. The HIFU is an attractive alternative to more invasive procedures for body contouring that may appeal to patients resistant to surgical options. It does not require general anesthesia and can be performed as an outpatient procedure thus substantially cutting treatment cost, recovery time, and decreasing the risk of side effects, complications, and patient discomfort. This procedure allows the surgeon to manipulate the device placed remotely on the body surface to precisely target tissues to be ablated beneath the dermis. A single session of HIFU treatment on abdominal subcutaneous adipose tissue has been demonstrated to achieve mean reduction in waist circumference of up to 4.7 cm. The procedure has been found to be safe and well tolerated. The commonly reported adverse events such as prolonged tenderness, ecchymosis, hard lumps, edema, and pain are all nonserious in nature and resolve spontaneously over time. In addition, the majority of patients surveyed have expressed their satisfaction with the outcome of the procedure. Conclusion: HIFU is a powerful means for selective tissue destruction.
Traditional body sculpting approaches involving invasive surgery while being effective in improving body contours are hampered by the associated morbidity due to the invasive procedure and the risk of deleterious side effects. With advances in technology-assisted modern medicine, the focus in recent years has been on the development of noninvasive body sculpting methods. These appeal to a wider audience than more invasive alternatives as they offer the advantages of reduced scarring, shorter procedure time, and markedly reduced recovery time and post-treatment complication.
Several minimally invasive body sculpting techniques involving the use of ultrasound, lasers, infrared light, radio frequency systems, either alone or in combination, and coupled with mechanical manipulation of the skin have demonstrated benefit in studies involving small patient cohorts. However, the majority of these minimally invasive procedures require multiple sessions while providing only short-lived benefits.
High-intensity-focused ultrasound (HIFU) is a promising, clinically relevant, thermal ablation technique that allows minimally invasive treatments while not necessitating the insertion of a probe into the target tissue, the hallmark of a true noninvasive procedure. Instead the source device in HIFU is placed on the surface of the body. The high-powered beam of ultrasound generated does not harm the tissues it traverses, but focuses at a predetermined focal point to enable selective destruction of targeted subcutaneous adipose tissue leaving surrounding tissues intact. This ensures trackless ablation of target tissues without the insertion of an applicator into the target area thus allowing for increased patient comfort and acceptability compared to traditional liposuction procedures. This noninvasive ablation procedure offers several advantages in that it allows the movement of the source device to target different tissue, while procedures that require probes to be inserted are only able to target-tissues in its immediate vicinity. Furthermore, the wound healing response attracts fibroblasts into the area, which together with heat denaturation of collagen that has occurred during the HIFU procedure, induces the formation of new collagen and tightening of septal fibers potentially resulting in a skin tightening effect.