Medicinal EMFs - Harnessing Electric & Magnetic Fields For Healing &
By Janet Raloff Science News, Vol. 156, No. 20 November 13,
1999, p. 316.
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.
Women at risk for osteoporosis got a
daily buzz on this prototype bone-growth stimulator in a Creighton University
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.
In a just-completed 2-year study,
researchers put the hind legs of aging ewes -- a model for osteoporosis in
people -- on this vibrating platform for a daily shake. The vibrated legs lost
less bone than the animals' untreated forelegs. Depending on the frequency of
the vibrations, some bones gained mass. (Simon Turner, Colorado State
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
"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
His group won FDA approval in 1979 for
the use of a pulsing EMF device for fusing broken bones. Pilla adds that the
major manufacturers of EMF-generating bone-growth stimulators still rely on this
basic waveform. Twenty years later, researchers still argue whether therapeutic
benefits trace to the electric fields or the magnetic fields that these devices
To study joint disease, orthopedic
surgeon Roy K. Aaron has been working with a pulsed EMF technique. He and
Deborah Ciombor, both at Brown University School of Medicine in Providence, R.I.
recently used it to treat a strain of guinea pigs that ordinarily begin showing
signs of osteoarthritis of the knee by 1 year of age. The researchers began EMF
therapy on one group of animals on their first birthday and continued it for 6
months. Another group received no treatment. At 18 months of age, most of the
treated guinea pigs had relatively mild disease and a few appeared to be free of
pain. All the untreated animals were crippled by the oseoarthritis.
[turkey wing bones]
Yellow dye highlights new growth in these
sections of wing bones from live turkeys. In contrast to the wing treated with
coils triggering a very tiny current in bone (left), the one placed in inactive
coils (right) shows no new tissue. (McLeod)
"I was so surprised by the
difference between the [treated and untreated groups] that I repeated the
experiment," Aaron says. The results were the same. The data demonstrate
that this treatment does not simply reduce symptoms, such as swelling, but
actually modifies the development of disease, he says.
EMF therapy also helps people with
established joint disease, Aaron says. This month, he's completing a clinical
trial of EMF therapy for men and women with advanced osteoarthritis in their
Two previous studies had found that EMFs
reduce pain and swelling. EMFs also have that effect in his new trial --
presumably, he says, "by changing the chemistry of the joint." Studies
by his team and others indicate that these fields can increase a joint's
production of natural anti-inflammatory agents, such as transforming growth
Not surprisingly, Aaron notes, medical
supply companies are now developing products, such as a glove with coils, to
deliver EMFs to arthritis-savaged joints.
Softer tissues also respond to these
fields. For instance, Pilla observes that many people with bone breaks
experience significant pain in muscles around their injuries. Shortly after EMF
therapy begins, however, that pain disappears.
Though the mechanism remains elusive,
Pilla says, the treatment seems to affect swelling, which can cause pain. If
this proves true, he says, EMFs might benefit people with carpal tunnel
syndrome, where swelling in the wrist pinches nerves going to the fingers.
Indeed, that's a possibility that Betty
F. Sisken of the University of Kentucky College of Medicine in Lexington would
like to explore. Currently, she's probing EMFs' direct influence on nerves.
In their initial studies, she and her
colleagues crushed a nerve in the hind leg of rats and then treated the animals
with EMFs for 4 hours daily. In one 6-day-long experiment, the treatment speeded
the nerve's recovery by 22 percent. In follow-up tests -- where 16 rats received
EMFs for 40 days and an equal number were allowed to heal unaided -- treated
animals again showed an accelerated recovery.
Despite some exploration of EMFs to heal
nerves and other soft tissue, the majority of studies continue to focus on bone.
James T. Ryaby, vice president of
OrthoLogic, a medical devices company in Tempe, Ariz., has been using what he
calls combined fields -- oscillating magnetic fields superimposed on a static
magnetic field. They appear to spur bone growth more quickly than the older type
of pulsed EMFs, Ryaby says.
Sections of bone from healthy female rat
(left) and two whose ovaries were removed 6 weeks earlier to model women who
lose bone after menopause. Bone from animal treated with combined EMFs (middle)
shows less loss than one from untreated rat (right). (John H. Kinney, Lawrence
Livermore National Laboratory)
What's more, the combined-field devices
require just a small percentage of the power used by typical pulsed EMF
generators. This means the combined-field devices can run on conventional
batteries, Ryaby says. His company is testing such a device for fusing vertebrae
in patients with back pain.
More tantalizing, says Ryaby, are the
data from a just completed study with female rats suggesting that the combined
fields can reverse the kind of bone loss women experience after menopause. After
removing the rodents' ovaries to simulate a postmenopausal state, Ryaby's team
watched the animals quickly lose bone. Six weeks later, some of the rats began
receiving combined-field therapy for 30 minutes a day. Within a little more than
a month, he says, the treated animals were regaining lost bone while their
untreated counterparts continued to lose it.
As exciting as the data are, Ryaby says
his company has no plans to develop the technology for human use. Women just
aren't likely to sign up for such therapy at menopause knowing that they would
likely have to continue it the rest of their lives.
Indeed, McLeod says, "a fear factor
associated with EMFs clearly haunts the therapeutic field."
Because of the stigma of EMFs, McLeod and
Clint Rubin have been looking for an alternative. The Stony Brook pair may have
found it in the bones themselves. Over the past 20 years, they have demonstrated
that during walking, jumping, or even just maintaining a balanced posture,
muscles exert enough strain on bones to generate microcurrents of electricity.
The discovery inspired the scientists to create a device to encourage the body
to make its own electric fields for building bones.
The resulting vibrating platform "is
highly innovative but not ready for prime time," says endocrinologist
Robert Marcus of the Veterans Affairs Medical Center in Palo Alto, Calif.
Overall, the benefit for women taking part in the Creighton study, led by Diane
Cullen, "was less than overwhelming," he says. He acknowledges,
however, that certain subgroups -- such as those, like Andreason, who started
out with the thinnest bones -- appeared to derive benefit. He's begun using the
device in a pilot project.
The platform's commercial developer,
Exogen of Piscataway, N.J., will fine-tune the device's frequency and the
recommended treatment times before undertaking any study of a larger group in
women, says Jack T. Ryaby, the company's scientific director.
McLeod says that in his newest tests with
aging sheep, platforms vibrating at 90 Hz increased bone mass. This suggests
that tripling the vibration frequency of the platform used for the Creighton
trial might build new bone, not just stabilize loss.
Moreover, if the sheep data translate to
people, he suspects that women would need just 8 minutes a day on the
faster-vibrating device. "This is really exciting because 8 minutes is
easy," he says.
For the larger range of problems, Pilla
holds that applied EMFs will be more useful. However, medical generators today
produce fields with a waveform that probably is far from optimal, he says.
Though experiments aimed at improving these generators and securing FDA approval
for devices with different waveforms would be costly, the payoff could be
tremendous, he believes.
To get to that payoff, scientists need to
learn more about why these fields work. Many of the researchers who are
developing new applications for these fields are therefore asking, What do cells
of the body see in EMFs?
"These fields are too weak to power
the biology or biochemistry that is active here," Pilla says. "They
only deliver enough energy to trigger something" -- much like a pacemaker
triggers contractions in the heart.
In Bioelectrochemistry and Bioenergetics
last February, he and his colleagues reported finding that pulsed EMFs appear to
increase the binding of ions to receptors on the surface of cells. For instance,
they've witnessed enhanced binding of calcium to the regulatory molecule called
calmodulin. This difference may prove important in stimulation of bone-cell
growth by EMFs, Pilla says.
EMFs can also increase bone cells'
production of insulinlike growth factor II, according to test-tube experiments
by Ryaby of OrthoLogic and his colleagues. This hormonelike molecule plays a key
role in bone growth and may be regulated by calcium binding to calmodulin.
At the BioElectromagnetics Society
meeting last June, Sisken's group reported on test-tube experiments showing that
pulsed EMFs can turn on a gene in damaged nerves. That gene plays a role in
triggering growth-related repair.
Brighton is also working to elucidate
which genes are altered by EMFs. "This is to me what's most exciting,"
he says. "We can turn genes on and off with this stuff."
McLeod and his group tend to focus on
physical effects of fields on cells. Their data indicate that EMFs may bias the
movement of cell structures that are otherwise jostled by the random pushes and
pulls of chemical and physical processes, McLeod says. He also finds that EMFs
can alter the environment in which cells grow and move within the body. For
instance, electric fields may alter the stickiness of surrounding proteins.
Indeed, he argues that changes in a cell's behavior may trace as much to
environmental alterations as to the cell's gene activity or membrane effects.
Changes in cellular behavior may not be
limited to the fields being used in therapy today, however. Aaron, for instance,
has examined effects of the 60-Hz fields generated by power lines and home
In the August Bioelectromagnetics, his
group reports that field strengths similar to those in the home and workplace
increased production of a protein that regulates proliferation and development
of cells destined to become bone. The EMFs also stimulated some maturation in
Aaron concludes that fields associated
with electric power may exert a beneficial influence on such tissues rather than
All this basic research may add up to
more effective devices and ubiquitous applications. For instance, Pilla says he
believes generators might one day be miniaturized to the size of a dime and cost
next to nothing.
He envisions disposable bandages
incorporating a tiny EMF device that would treat problems ranging from ankle
sprains to bedsores.
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Roy K. Aaron Brown University School of
Medicine Department of Orthopaedics Providence, RI 02906
Carl T. Brighton University of
Pennsylvania School of Medicine Department of Orthopaedic Surgery 425 Stemmler/6081
Philadelphia, PA 19104
Deborah M. Ciombor Brown University
School of Medicine Department of Orthopaedics Providence, RI 02906
Diane Cullen Creighton University
Department of Medicine-Osteoporosis SJH Room 4820 Omaha, NE 68178
Deborah M. Ciomber Brown University
Department of Bio. Med. Orthopaedics Box G-RI Providence, RI 02912
Kenneth J. McLeod State University of New
York, Stony Brook Program in Bioengineering Health Science Center T18-030 Stony
Brook, NY 11794-8181
Arthur A. Pilla Mount Sinai School of
Medicine Department of Orthopaedics Bioelectrochemistry Laboratory New York, NY
Jack Ryaby Exogen, Inc. 10 Constitution
Avenue P.O. Box 6860 Piscataway, NJ 08855
Betty F. Sisken University of Kentucky
Department of Anatomy and Neurobiology Center for Biomedical Engineering
Lexington, KY 40506
Copyright © 1999 Science Service. All
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