The Therapeutic Use of Electromagnetic Fields in Plastic Surgery

Before the 20th century, humankind was almost never exposed to sources of radio frequency (RF), electromagnetic fields (EMFs) other than those of the sun, or occasional blasts from other stellar sources. In this century, especially in recent years, there has been an explosion of uses of electromagnetic fields in the home, community, and workplace. Common sources of RF fields include computer monitors, AM radios, industrial induction heaters, RF heat sealers, medical diathermy, FM radios, mobile telephones, TV broadcasts, radar, and microwave ovens1 (see Table). An EMF can produce beneficial or adverse health effects, which may vary depending on the frequency spectrum of the source and its harmonics, the power of the devices, the duration of exposure, and the distance of the person from the source.

Table

Common sources of EMF and their frequency

Device	Frequency and harmonics
Power lines	50 to 500 Hz
Computer monitors	3 to 30 kHz
AM radios and industrial induction heaters	30 kHz to 3 MHz
Therapeutic ultrasound	1 to 3 MHz
Medical short-wave diathermy	10 to 300 MHz
Short-wave radio broadcast	3 to 50 MHz
FM broadcast	87 to 107 MHz
Television broadcast	50 MHz to 3 GHz
Mobile telephones	50 MHz to 3 GHz
Microwave ovens and communications	3 to 30 GHz
Radar and satellite links	3 to 30 GHz
Solar radiation	3 to 300 GHz

In the home, microwave ovens, mobile telephones, burglar alarms, TV sets, and hair dryers are a few of the devices that emit EMFs of up to 10 W/m2. In the community, the most common sources are commercial radio and TV broadcasting and telecommunication facilities, which in the average US urban center radiate a field of 50 W/m2. In the workplace, dielectric heaters used for wood lamination and the sealing of plastics, industrial electric heaters, and medical diathermy expose workers to greater than tens of W/m2. In medicine, the primary sources of exposure and overexposure exclusive of radiology are medical diathermy equipment to treat pain and inflammation and electrocautery devices. These medical devices are regulated in the United States and internationally.2–6

Claims that static magnets may relieve pain and tension have stimulated interest in this field. There are many popular books7–11 and anecdotal reports “documenting” such claims, but controlled clinical trials are rare. In November 1997 a double-blind controlled trial in patients at Baylor Medical Center who had polio demonstrated statistically significant relief of musculoskeletal pain using static magnets.12 There does not seem to be any harm in exposure to common static magnets on a long-term basis; however, it will be several years before valid large-scale studies will be available.

Alternating current (AC) EMFs are of much more interest and may have more significant application. The primary effect of high-power RF EMF (more than 1 MHz) appears to be heating, whereas below 1 MHz it induces weak electrical currents in tissues. Notwithstanding the potential beneficial effects of EMFs, grave concerns have been voiced about the health risks, on the basis of studies performed in Sweden, Denmark, and the United States.6,13–20 A massive scientific review by the World Health Organization under the auspices of the International EMF Project (Munich, November 1996) reported no demonstrable adverse health effects, although researchers would not exclude heretofore undiscovered problems.21–23 In the United States, the majority of the participants in the June 1998 Working Group Report of the National Institute of Environmental Health Sciences (NIEHS) (a 500-page report with hundreds of references from the world literature) concluded that “ELF [extra low frequency] EMF are possibly carcinogenic to humans.”24 In noncancer adverse health effects, “none of the evidence for adverse health effects seen after exposure to ELF EMF achieved a degree of evidence exceeding ‘inadequate‘ (for humans) or ‘weak’ (for experimental animals).”25 In other biologic effects “there appears to be substantial, accumulating evidence that complex clinical exposures to PEMF [pulsed electromagnetic field] have a significant effect on the primary bone healing processes.”26 It is this finding that generates interest in the study of the overlying soft tissues. An excellent listing of more than 100 research articles funded by the National Institutes of Health (NIH) and links to several databases and dozens of other sites are available online at the NIH.27

Brian M. Kinney, MD, Los Angeles, CA, is a board-certified plastic surgeon and an ASAFS member.

For several decades diathermy has been used to treat a variety of conditions. The Food and Drug Administration (FDA) recognizes that it treats soft tissue pain and edema and locally stimulates circulation. Proponents claim that it increases local blood flow, relaxes skeletal muscles, relieves pain, “speeds” healing, prevents adhesions and scar formation, and increases the white blood cell count.28 Hal Mettler introduced the ultrasonic diathermy device for local heating of tissues into the US marketplace in 1957, and it has been in use ever since, without significant study or change. There are many devices on the market, and they generally use a frequency range of 1 to 3 MHz in a continuous wave with transducers of 5 to 10 cm². “Diathermy,” as used by the FDA, implies that the tissues are heated by at least 1° C. There is widespread acceptance of these devices in physical medicine and rehabilitation, as well as in orthopedics for sports injuries and musculoskeletal conditions.

The use of PEMFs decreases the total exposure of the tissues to the field compared with a continuous wave but clinically still seems to effectively treat pain and edema. However, clinical trials under a variety of conditions are lacking. It is still unknown which frequencies, power settings, and treatment patterns are beneficial or harmful. The orthopedic literature shows bone healing in double-blinded treatment of delayed union of tibial fractures.29 Melatonin production has been shown to be altered by low-frequency EMF in animals, but not in human beings.30–33 Gene expression has also been altered in some animal studies at low frequencies, but data are conflicting. Relatively few studies have been reported of the effects of EMF on gene mutation. As is often the case, the exposure protocols differ widely, and no consistent picture has evolved on possible effects.34 The work of Mayrovitz and Larsen35,36 has demonstrated that PEMFs increase the microcirculation as measured by laser Doppler, red blood cell perfusion, and skin temperature in healthy subjects, and in diabetic patients with lower extremity ulcers.

Currently, there is only one PEMF device with FDA clearance for marketing. The SofPulse® (Electropharma-cology, Inc., Pompano Beach, FL) was given a 510k (substantial equivalence to “diathermy”) in 1991, although it is in essence “nonthermic” diathermy by virtue of not increasing the temperature of the tissues by greater than 1° C. The frequency and pulse width of this device are fixed at 27.12 MHz and 65 μsec, respectively, whereas the duty cycle and pulse frequency vary.28

To date there have been no studies of PEMF in the plastic surgery literature, but at least one center believes it has observed clinical responses in large numbers of patients (Sydney Coleman, MD, oral communication, 1998). Almost 2 years ago, I started using this device on selected patients with postoperative pain and edema. Most patients stated that the device was “working.” Without adequate controls, however, it was not possible to determine if the response was due to the device or a placebo effect. Therefore a blinded, controlled pilot study was designed (the completed study will be submitted for publication in the future). Briefly, with patients undergoing full-face laser resurfacing, one side was treated with a functioning SofPulse® machine and one side with a non-functioning machine immediately before and after surgery and twice for 30 minutes on postoperative days 1 through 3. Careful facial measurements were obtained preoperatively and on postoperative days 1, 2, 3, 7,14, and 28. The “blinded” physician was able to clinically determine the treated side in all seven patients in the study by postoperative day 2, and the clinical difference in edema persisted until postoperative day 7 or longer in several patients. This initial series must be repeated in larger numbers of patients and confirmed in multiple centers before strong conclusions can be drawn, but these early results are very encouraging.

Because some pain and edema accompany any degree of manipulation of the soft tissues, EMF therapy would seem to have almost universal application in the aesthetic surgery patient. Fewer analgesics, faster reduction in postoperative swelling, and other potential benefits warrant further investigation.