6. Radiofrequency energy in esthetic procedures

Energy has been applied in some form to tissue since the beginning of recorded history. The practice of applying heat to tissue through the use of cauters was used for thousands of years as an invaluable method of controlling hemorrhage. Continuous improvement of methods for utilizing the beneficial effects of heat on tissue eventually led to the development of the basic concepts of electrosurgery we know today. In October of 1926, Dr. Harvey Cushing used an electrosurgical unit developed by Dr. William T. Bovie to successfully remove a highly vascularized brain tumor from a patient after previous failed attempts. Today, electrosurgical instruments are used in the majority of surgical procedures performed worldwide [35].

Radiofrequency-based devices for skin rejuvenation became popular in the early 1990s, as a noninvasive device (Thermage) was used to improve tissue tone and texture. Other devices rapidly followed and utilized monopolar, bipolar, and multipolar configurations to treat the skin surface. While the Bovie cautery device has been used for decades in the subcutaneous plane, an open approach was needed. The first subdermal device to be used in a minimally invasive manner was the BodyTite device, which in 2008 had an accompanying liposuction cannula. The monopolar Thermi device utilizes a 10- or 15-cm slender monopolar cannula in a subdermal manner to heat soft tissue at the level of the fibroseptal network. These devices are characterized as "bulk heating" devices and create a radiant pattern of tissue heating from the probe tip outward.
