- PHOENIX, (UPI) - Researchers
at Good Samaritan Regional Medical Center and the University of Arizona
reported Thursday two partially paralyzed men are walking thanks to
battery-powered
devices surgically implanted in their spines.
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- In an interview with United Press International, Dr.
Richard Herman said his team is using an electrical stimulation device
used to treat chronic pain to "modulate or alter" signals sent
by the spine to nerves in the feet and legs. The process only works on
patients with partial spinal cord injuries who still have some sensation
in their legs.
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- The Foundation for Spinal Cord Injury Prevention, Care
and Cure estimates there are about 11,000 new spinal cord injury cases
in the United States each year. Half of these injuries are termed partial
spinal cord injuries and about 30 percent of this group might benefit from
this device, Herman said.
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- Herman reports in the February issue of the medical
journal
Spinal Cord he implanted the device, called LiteGait and made by Mobility
Research of Tempe, Ariz., in a 43-year-old man who had been wheelchair
dependent for more than three years after sustaining a partial spinal cord
injury. The man did retain some sensation and control in his legs and so
could work out on treadmill before surgery, but only with great
effort.
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- Before surgery, the man could walk 50 feet in three
minutes,
Herman said.
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- "Within weeks of surgery, he walked 50 feet in less
than 60 seconds," said Herman, who added a healthy person can walk
50 feet in about 14 seconds.
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- Moreover, the walking was achieved with "a sense
or perception of lightness or little effort, Herman said. "Ultimately,
he could walk about 1,000 feet around his home and eventually he could
walk to the car and to a shopping center."
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- The device includes two sets of four electrodes, which
are implanted on each side of the spine below the sight of the injury.
These electrodes are connected to a receiver implanted in the
abdomen.
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- "The entire device is completely implanted. There
are no external wires," Herman said. When the patient wants to walk,
he places a disk-like antenna over the receiver in the abdomen. The
antennae
transmits energy signals from a remote power source, which is "about
the size of cell phone," he added. "It can be attached to a belt
or carried in the pocket."
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- The remote power source is programmed with exact
information
about precise "energy parameters" needed for correct stimulation
of the spine. The whole system is powered by 9-volt battery.
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- Although the journal article describes one patient with
the implant, Herman said he has already implanted a second patient, who
also is now able to walk.
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- Electrical stimulation of nerves and muscles in not a
new concept, said Dr. Ron Triolo, of the department of orthopedics and
biomechanical engineering, Case Western Reserve University School of
Medicine
and the Cleveland Functional Electrical Stimulation Center. The Cleveland
FES Center has used various electrical devices to improve standing, walking
and sitting in spinal injury patients, he said.
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- But the Cleveland researchers concentrate on stimulating
nerves and muscles in the extremities, while Herman -- who trained at Case
-- is directly stimulating the spine.
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- Triolo told UPI that Herman's study demonstrates that
electrical stimulation can successfully modulate "the nervous system
centrally" which allows the nerves and muscles to work together in
new ways that allow the patient to walk. But for this approach to work,
the patient must have retained both "sensation and some degree of
voluntary movement."
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- "Electrical stimulation has been the focus of
researchers
for some time," Triolo said. "We've learned that controlling
the movement of the human body is incredibly difficult and so these
successes
are encouraging."
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- Copyright © 2002 United Press International. All
rights reserved.
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