Corticosteroid iontophoresis to treat carpal tunnel syndrome: a double-blind randomized controlled trial.

Even though injection of corticosteroids into the carpal tunnel alleviates the symptoms of mild to moderately severe carpal tunnel syndrome (CTS), it has not gained universal popularity due to its invasiveness. This study was designed to investigate the effectiveness of dexamethasone iontophoresis as a noninvasive method of treating CTS. We carried out a double-blind randomized controlled trial comparing six sessions of iontophoresis with 0.4% dexamethasone sodium phosphate with distilled water in 17 patients. Outcome measures including nerve conduction studies, the Levine Self-Assessment Questionnaire, and the Semmes-Weinstein Monofilaments were done monthly for 6 months after intervention. Most of the outcome measures did not show any significant change following treatment. Although there was subjective improvement of symptom severity scores in the treatment group as quantified by the Levine Self-Assessment Questionnaire, similar improvement was also observed in the control group (P < 0.05). Although corticosteroid iontophoresis is feasible in clinical settings and is well-tolerated by patients, iontophoresis of 0.4% dexamethasone was not effective in the treatment of mild to moderate CTS. Muscle Nerve 39: 627-633, 2009.