Clue to Carpal Tunnel Syndrome Found
Study Links Repeated Finger Movements to Tissue Damage in Wrist
Nov. 16, 2006 -- A microscopic look at carpal tunnel syndrome may have
uncovered the cause of the painful condition.
The carpal tunnel is a narrow passage through the bones and ligaments of the
wrist. It protects a main nerve leading to the hand and the tendons that bend
In carpal tunnel syndrome, there is pressure on the nerve. That causes
worsening pain, weakness, and/or numbness in the hand and wrist, sometimes
shooting up the arm.
Although workers who perform repetitive hand motions frequently get carpal
tunnel syndrome, there has been little evidence to prove the link. That
evidence may now be here.
Mayo Clinic researchers Anke M. Ettema, MD, Peter C. Amadio, MD, and
colleagues used powerful microscopes to look inside the carpal tunnels of 11
patients with carpal tunnel syndrome. They also looked at the carpal tunnels of
14 normal cadavers and two cadavers of people with a history of carpal tunnel
The study found several parallel layers of tissues connected to the tendons
in the carpal tunnel. As the tendon slides through the carpal tunnel, the
connections pull these tissues along with it. It's a bit like extending an arm
covered with several layers of sleeves.
In all of the carpal tunnel syndrome patients, the researchers found, the
connective tissues appeared to be damaged, causing bulky fibers and scar
tissue. As might be expected if the damage were the result of injury, the worst
damage occurs nearest to the tendon.
Ettema, Amadio, and colleagues suggest that violently or repeatedly moving
adjacent fingers in different directions shears connective tissues in the
carpal tunnel and leads to carpal tunnel syndrome.
The findings must be confirmed, of course. But if they are, they suggest new
treatments for the disabling condition.
In the future, the researchers say, it might be possible to detect early
damage in the carpal tunnel and treat it -- perhaps with new drugs -- before
carpal tunnel syndrome develops.
Ettema, Amadio, and colleagues report their findings in the November issue
of Plastic and Reconstructive Surgery.