**6. Evolution of energy based devices**

The early methods of performing closed liposuction included hand held aspiration (Toomey syringe liposuction) connected to a cannula, or connecting the suction cannula to a suction pump with one atmosphere of negative pressure, but still requiring manual movement of the cannula to break up and remove the fat. One of the most important advances in facilitating the removal of fat in a closed system was the introduction of Power-assisted Liposuction. Several devices were manufactured and quickly adopted to facilitate the removal of fat with less effort.

Following the introduction of Power-assisted Liposuction, the development of Ultrasonic Energy based emulsification of the fat followed by suction lipectomy was introduced by Michele Zocchi, M.D. [35]. There was an evolution in the machinery required to perform the emulsification procedure, but the surviving technology was manufactured under the name of Vaser, engineered by Sound Surgical Technologies. This method of dissolving fat and causing energy to be delivered to the dermis has found its' most important application in "High Definition Liposuction", importantly advanced and refined by Alfredo Hoyos [36]. Other indications for ultrasonic emulsification of fat include the closed treatment of gynecomastia.

The technique of applying freezing temperature to dissolve the fat through apoptosis (CoolSculpt) has received important acceptance in the Cosmetic Surgery community, has enormous social media presence, but complications are common with neo-fat formation and "shark-bite" contour complications being reported.

Laser based energy has also been developed (Smart Lipo) where a small diameter probe is inserted into the fatty deposit and energy is applied to dissolve the fat. This requires a two step procedure, is quite tedious due to the small size of the fiber, with the risk of skin burns.

Radiofrequency based energy has emerged as the most commonly energy based method of emulsifying fat and stimulating fibrous septae contraction as well as dermal tightening. Impressive pre and post-op measurements of circumference are seen when this energy based system is used alone or in combination with suction assisted liposuction. Real time monitoring of internal and external body temperatures ensure safe application of the energy (InMode,Ltd., Yokneam, Israel).

Plasma based energy systems are available (Renuvion J-Plasma) which dissolve the fat, but lack sophisticated temperature monitoring.

High intensity focused ultrasound devices are available, but has enjoyed limited market penetrance due to the minimal improvement shown when compared to other energy sources.
