Randomized controlled trial of nocturnal splinting for active workers with symptoms of carpal tunnel syndrome.

OBJECTIVES: To determine whether nocturnal splinting of workers identified through active surveillance with symptoms consistent with carpal tunnel syndrome (CTS) would improve symptoms and median nerve function as well as impact medical care. DESIGN: Randomized controlled trial. SETTING: A Midwestern auto assembly plant. PARTICIPANTS: Active workers with symptoms suggestive of CTS based on a hand diagram. INTERVENTION: The treatment group received customized wrist splints, which were worn at night for 6 weeks; the control group received ergonomic education alone. MAIN OUTCOME MEASURES: Change in wrist, hand, and/or finger discomfort, carpal tunnel symptom severity index, median sensory nerve function, and the percentage of subjects who had carpal tunnel release surgery. RESULTS: The splinted group, unlike the controls, had a significant reduction in wrist, hand, and/or finger discomfort and a similar trend in the Levine carpal tunnel symptom severity index, which was maintained at 12 months. A secondary analysis showed that more median nerve impairment at baseline was associated with less clinical improvement among controls but not among the splinted group. CONCLUSIONS: Workers identified with CTS symptoms in an active symptom surveillance tended to benefit from a 6-week nocturnal splinting trial, and the benefits were still evident at the 1-year follow-up. The splinted group improved in terms of hand discomfort regardless of the degree of median nerve impairment, whereas the controls showed improvement only among subjects with normal median nerve function. Results suggest that a short course of nocturnal splinting may reduce wrist, hand, and/or finger discomfort among active workers with symptoms consistent with CTS.