Medical surveillance for carpal tunnel syndrome in workers.

Carpal canal size was examined as a risk factor associated with carpal tunnel syndrome in the workplace. Seven of 14 electricians had symptoms of carpal tunnel syndrome. When cross-sectional areas were measured by computed tomography (CT), affected workers had a cross-sectional area of 1.75 +/- 0.21 cm2; control values were 2.53 +/- 0.15 cm2 (p less than 0.05). Subjects with a subclinical syndrome had an area of 1.83 +/- 0.22 cm2, which was similar to the group with symptoms. Wrist circumference was not a predictor of the smallest carpal canal area. Unusual bony and soft tissue structures within the carpal canal were easily identified with CT.