Spasticity is a complex syndrome requiring extensive and complete treatment. Injections of botulinum toxin type A decrease muscle tone in spastic muscles of the hand and improve the use of the upper limb. However, rehabilitation and different non-invasive treatments should also be considered.

Shock waves are defined as a sequence of single sonic pulses characterised by high peak pressure (100 MPa), fast pressure rise (< 10 ns) and short duration (10 μs). Twenty patients, with upper limb spasticity post stroke were enrolled in the study. The patients (12 men and eight women) had a mean age of 63 years (36–76 years). An electromagnetic coil lithotriptor (Modulith SLK® by Storz Medical AG) provided with in-line ultrasound, radiographic, and computerised aiming (Lithotrack® system) was used. Flexor muscles of the forearm were treated with 1500 shots, and 3200 shots were used for interosseous muscles of the hand (800 for each muscle). The energy applied was 0.030 mj/mm. The protocol consisted of one placebo treatment session in which no shock waves were applied, followed 1 week later by one active shock wave treatment session. The Ashworth Scale was used to study the muscle tone activity in patients. No changes in the Ashworth score were noted in hand and wrist flexion after placebo stimulation. After real treatment the hand muscles and finger flexion in particular showed a marked reduction in spasticity with a change in the Ashworth scale from 3 to 0. At 1, 4, and 12 weeks, a slight increase in muscle tone was observed for all subjects. Needle EMG was performed at 4 weeks. No denervation was observed.

The main finding of this preliminary study is that a single active treatment of shock wave therapy in spastic muscles in a patient affected by stroke resulted in a significant reduction in muscle tone. In contrast, no effect was noted after placebo stimulation. Nitric oxide synthesis has been suggested to be one of the most important mechanisms to explain the effectiveness of shock waves in the treatment of different soft tissue diseases. Shock wave therapy appeared to be safe, non invasive and without complications. Our findings suggest that shock wave therapy may be useful in decreasing flexor tone and functional disability in patients with spasticity of the hand, with a long-lasting effect. This therapy could open a new field of research in the treatment of spasticity. Further studies with a larger group of patients are, therefore, necessary.