Effects of Thermal and Pulsed Ultrasound on Pain and Function in Patients With Carpal Tunnel Syndrome

Abstract

OBJECTIVE: While ultrasound therapy is common for carpal tunnel syndrome, the relative merits of thermal versus pulsed ultrasound remain unclear. This study compares their therapeutic effects. DESIGN: This is a randomized, double-blinded, placebo-controlled trial. Ninety-two adults aged 30-60 yrs with mild-moderate carpal tunnel syndrome (characteristic symptoms, positive clinical tests, abnormal electrophysiology) were randomized into four groups receiving 4-wk night splinting plus 12 ultrasound sessions: group A: 1 MHz, 1.0-W/cm 2 continuous ultrasound for 5 mins; group B: 1 MHz, 25% duty cycle, 1.0-W/cm 2 pulsed ultrasound for 15 mins; group C: 5 mins thermal plus 15 mins pulsed ultrasound; group D: sham ultrasound for 15 mins. Pain, function (Disability of Arm, Shoulder and Hand-Arabic), nerve conduction, and grip strength were measured at baseline, 4, and 8 wks. RESULTS: Thermal and pulsed ultrasound groups improved in all outcomes versus placebo over 8 wks ( P < 0.05). Pulsed ultrasound decreased pain and distal motor latency more than placebo ( P < 0.05). Thermal ultrasound increased sensory nerve action potentials versus placebo ( P < 0.05). CONCLUSIONS: Thermal and pulsed ultrasound with splinting improved pain, disability, grip strength, and nerve conduction in carpal tunnel syndrome. Pulsed ultrasound was optimal for pain and motor function, while thermal ultrasound enhanced sensory nerve function.