Four thousand people have surgery to correct it every year, but about a third still can't get the relief they seek.
Richard Hinrichs, an associate professor of exercise science at ASU, teamed up with Benjamin Sucher, an osteopathic physician, about 12 years ago to develop a non-surgical treatment for carpal tunnel syndrome and have made strides to finding one.
People suffering from carpal tunnel syndrome may experience wrist pain, tingling, numbness and loss of grip strength when a tendon in the arm gets squeezed underneath a ligament that runs across the wrist.
"If you overuse your fingers and your tendons swell, they press a nerve up against the ligament and then you get a pinched nerve," Hinrichs said.
The current treatment for the syndrome is for a surgeon to cut through the restricting ligament to ease the pressure.
"Our theory is to stretch the ligament," Hinrichs said. "And if we can do that, we can relieve the pressure without surgery."
The stretching would be a two-part process, first involving a doctor gently bending the wrist to stretch the ligament.
Sucher said he has already been doing this.
"I have been using this for years on patients and have had excellent clinical results," Sucher said.
Sucher and Hinrichs wanted to create a way to continue the stretching process outside the doctor's office and decided to work on a bracelet that would put pressure on certain parts of the wrist to stretch the ligament while the patient is at home, even asleep.
In order to get a grant for the production of the bracelet and to test on patients, Sucher and Hinrichs had to prove that the ligament is stretchable.
To test this theory of stretching the ligament, they used cadaver arms from the UA medical department, funded by a $25,000 grant from the American Osteopathic Association.
They used 10 male arms and 10 female arms, placing pins in the bones at the wrist, and then weights were hung on the pins to stretch the ligament.
The data taken from the cadavers showed that women responded better to the treatment.
"This would be good if the results apply to living subjects, which we aren't entirely sure, because carpal tunnel syndrome is more common in women," Hinrichs said.
The next step is to do more testing with prototypes of the bracelets.
"We don't know how well you could tolerate the pressure from the bracelets for eight hours," Hinrichs said.
They wrote a grant proposal to the National Institute of Health for four more years of work, but the proposal was turned down.
Both researchers said they would continue to do more research on their own and apply again.
"If the NIH thinks there is promise, they will fund a big study for us," Hinrichs said.
Reach the reporter at susan.padilla@asu.edu.
