Abstract
OBJECTIVE: To assess the effect of a 40 mg methylprednisolone injection proximal to the carpal tunnel in patients with the carpal tunnel syndrome. DESIGN: Randomised double blind placebo controlled trial. SETTING: Outpatient neurology clinic in a district general hospital. PARTICIPANTS: Patients with symptoms of the carpal tunnel syndrome for more than 3 months, confirmed by electrophysiological tests and aged over 18 years. INTERVENTION: Injection with 10 mg lignocaine (lidocaine) or 10 mg lignocaine and 40 mg methylprednisolone. Non-responders who had received lignocaine received 40 mg methylprednisolone and 10 mg lignocaine and were followed in an open study. MAIN OUTCOME MEASURES: Participants were scored as having improved or not improved. Improved was defined as no symptoms or minor symptoms requiring no further treatment. RESULTS: At 1 month 6 (20%) of 30 patients in the control group had improved compared with 23 (77%) of 30 patients the intervention group (difference 57% (95% confidence interval 36% to 77%)). After 1 year, 2 of 6 improved patients in the control group did not need a second treatment, compared with 15 of 23 improved patients in the intervention group (difference 43% (23% to 63%). Of the 28 non-responders in the control group, 24 (86%) improved after methylprednisolone. Of these 24 patients, 12 needed surgical treatment within one year. CONCLUSION: A single injection with steroids close to the carpal tunnel may result in long term improvement and should be considered before surgical decompression.