Thirty-eight (49 per cent) of seventy-seven paraplegic patients whose
level of injury was at or caudad to the second thoracic vertebra were found
to have signs and symptoms of carpal tunnel syndrome. The prevalence of
carpal tunnel syndrome was found to increase with the length of time after
the injury. In the eighteen patients in whom manometric studies were done,
the carpal tunnel pressures when the wrist was in the neutral position were
higher than those that have been reported in non-paraplegic patients who
did not have carpal tunnel syndrome but were lower than the values in
non-paraplegic patients who did have the syndrome. When the wrist was in
flexion, the pressures were similar to the values that have been reported
for non-paraplegic patients. However, in the paraplegic patients,
regardless of whether or not they had carpal tunnel syndrome, the pressures
that developed when the wrist was in extension were significantly higher
than those in non-paraplegic patients, regardless of whether or not they
had carpal tunnel syndrome. Most of the activities of daily living of
paraplegic patients, including the maneuver to relieve ischial pressure
that consists of arising from the seated position using the extended arms,
are performed with the wrists locked in maximum extension. The pressure
that develops in the carpal canal during this forced extension of the
wrist, probably combined with the repetitive trauma to the volar aspect of
the extended wrist while propelling a wheelchair, contributes to the high
frequency with which carpal tunnel syndrome is found in paraplegic
patients.