External shock waves therapy in dystonia: preliminary results.

Extracorporeal shock wave therapy (ESWT) has been shown to reduce hypertonia in patients with upper motor neuron syndrome without any side effect. The aim of the present study is to investigate whether ESWT could be useful also in patients with dystonia. We evaluated three patients with secondary dystonia and three patients with idiopathic writer's cramp. Placebo treatment was performed in each patient. ESWT was administered during four sessions (once weekly) to the target muscles of hand and forearm using an electromagnetic lithotripter (Modulith SLK - Storz Medical). Clinical evaluation was performed using the Unified Dystonia Rating Scale in patients with secondary dystonia and the Arm Dystonia Disability Scale in patients with writer's cramp. After treatment, the three patients with secondary dystonia showed a marked improvement which lasted at least until 1 month after the last session. In the patients with writer's cramp, the improvement after ESWT was less consistent being effective only in two subjects. There were no associated adverse effects. Extracorporeal shock wave therapy is probably an effective and safe treatment for upper limb dystonia, particularly for the secondary forms. Larger randomized studies are needed to confirm these preliminary results.