Ultrasound treatment for treating the carpal tunnel syndrome: randomised “sham” controlled trial

Objective: To assess the efficacy of ultrasound treatment for mild to moderate idiopathic carpal tunnel syndrome. Design: Randomised, double blind, “sham” controlled trial with assessments at baseline, after 2 weeks’ and 7 weeks’ treatment, and at a follow up assessment 6 months later (8 months after baseline evaluation). Setting: Outpatient clinic of a university department of physical medicine and rehabilitation in Vienna. Subjects: 45 patients with mild to moderate bilateral carpal tunnel syndrome as verified by electroneurography. Intervention: 20 sessions of ultrasound (active) treatment (1 MHz, 1.0 W/cm(2), pulsed mode 1:4, 15 minutes per session) applied to the area over the carpal tunnel of one wrist, and indistinguishable sham ultrasound treatment applied to the other. The first 10 treatments were performed daily (5 sessions/week); 10 further treatments were twice weekly for 5 weeks. Main outcome measures: Score of subjective symptom ratings assessed by visual analogue scale; electroneurographic measures (for example, motor distal latency and sensory antidromic nerve conduction velocity). Results: Improvement was significantly more pronounced in actively treated than in sham treated wrists for both subjective symptoms (P<0.001, paired t test) and electroneurographic variables (motor distal latency P<0.001, paired t test; sensory antidromic nerve conduction velocity P<0.001, paired t test). Effects were sustained at 6 months’ follow up. Conclusion: Results suggest there are satisfying short to medium term effects due to ultrasound treatment in patients with mild to moderate idiopathic carpal tunnel syndrome. Findings need to be confirmed, and ultrasound treatment will have to be compared with standard conservative and invasive treatment options.