Medicinal EMFs

Science News, Nov 13, 1999 by Janet Raloff

Harnessing electric and magnetic fields for healing and health

Jan Andreason used to get slightly rattled every day--all in the name of science.

Though in her mid-50s, Andreason has the thin, fragile bones seldom found in women under 70. Hoping to fight off further ravages of osteoporosis, she had volunteered in late 1997 as a subject in a year-long trial of a treatment for the brittle-bone disease.

Participation wasn't difficult. All Andreason had to do was submit to twice-daily bouts on a 75-pound contraption installed in her guest bedroom by the Creighton University School of Medicine in Omaha, Neb. Resembling an upright bathroom scale with handlebars, the vibrating machine sent a gentle buzzing through every bone in her body.

Most mornings, Andreason read the newspaper or blow-dried her hair while putting in 10 minutes on the device. Before bedtime, she'd step on the platform for a second 10-minute buzz.

This shaky therapy may represent the future of bone health. Preliminary data from Andreason and 51 other postmenopausal recruits suggest that in some cases, the platform's vibrations may be able to halt the rapid bone loss that occurs in most older women, says Kenneth J. McLeod, a co-inventor of the device.

Even newer data from a 2-year study of sheep suggest that scientists might be able to tailor the regimen to increase the mass of the bones most vulnerable to age-related thinning.

The vibrating platform appears to work by triggering bones to generate tiny electric fields, explains McLeod of the State University of New York at Stony Brook, who directed the sheep experiments. These tiny currents may turn on genes that affect bone remodeling and growth.

The experimental osteoporosis-fighting machine represents just one technology in a wave of new applications of electric and magnetic fields (EMFs) to bone injuries and related problems. All build on decades of work by physicists and surgeons. Though much of this work remains experimental, the Food and Drug Administration acknowledges that when properly applied, EMFs can make for good medicine.

Most news reports about EMFs have focused on emanations from power lines, building wiring, and appliances. They have chronicled the continuing controversy over whether these fields have unhealthy effects, such as perturbed sleep patterns (SN: 1/10/98, p. 29), altered heart rhythms (SN: 1/30/99, p. 70), and cancer (SN: 2/21/98, p. 119). Yet while these risks have grabbed headlines, EMFs have been quietly edging into medicine.

Over the past 20 years, FDA has approved EMF generators for two medical uses. The devices are used frequently to treat bone fractures that have stopped healing. EMF treatment is also increasingly being applied to fuse spinal vertebrae in people with intractable back pain.

The first inkling of potential benefits from EMFs emerged during the 1950s, McLeod notes. That's when a series of experiments showed that bone is piezoelectric, meaning that bending or deforming its crystal structure creates local electric currents. Physiologists quickly linked these currents to bone growth in studies that seemed to explain why exercise strengthens bones and immobilization weakens them. This link suggested that electric currents could be applied as therapy.

From the beginning of EMFs' ascendancy to medical respectability, Carl Brighton has been an active player. An orthopedic surgeon at the University of Pennsylvania School of Medicine in Philadelphia, he was the first doctor to treat a fracture with EMFs.

In 1971, Brighton was faced with the case of a Camden, N.J., woman whose 9-month-old ankle fracture steadfastly refused to heal. From his experiments, Brighton knew that electric fields have the capacity to knit unfused bones in animals. So, his team poked a metal pin into the woman's leg, anchored the pin to the broken bone, and hooked it up to a battery. Then, they put the leg in a cast and sent the woman home with the battery connected.

"Twelve weeks later, her bone was healed," Brighton recalls. The researchers' explanation was that the small current delivered by the battery to the patient's ankle--which they measured at 10 microamps--spurred specialized cells to grow new bone.

Over the past quarter century, orthopedic researchers have been refining their techniques. Brighton developed one of the earliest of those modifications --delivery of fields via electrodes placed on the skin instead of on the bone. This method remains the only one that FDA has approved for fusing spinal vertebrae, he notes.

More recent techniques enable fields to be delivered without electrodes touching the body. This is the most important therapeutic advance in recent years, suggests Arthur A. Pilla. A biophysicist at the Mount Sinai School of Medicine in New York City, he explains that the newer devices transfer a field's energy into the body from wire coiled around, but not touching, the injured area.

For EMFs to penetrate the body, the coils must carry a pulsing electric current, he explains--not the simpler direct currents associated with electrode-generated fields. In designing the waveform for these oscillating fields--their shape, amplitude, and frequency--"we were guided by measurements people were making of natural, mechanically induced voltages in bone," Pilla recalls. The waveforms of these therapeutic EMFs differ dramatically from those generated by power lines and indoor wiring.