This study evaluates the impact of extracorporeal shock wave treatment after microsurgical coaptation of finger nerves. Participants will be randomized into two treatment groups with different settings and a sham group. The participants will thereafter followed-up in a prospective, double-blind study design.

Extracorporeal shock wave treatment is CE certified in Austria, Europe and licensed for indications like achillodynia, epicondylitis, or tendinitis calcanea. The Orthogold 100 device by MTS Medical UG will be used for this study.

Defocused low-energy extracorporeal shock wave therapy (ESWT) has gained acceptance as a therapeutic tool in different medical settings. It has been shown, that shock waves stimulate of the metabolic activity of different cell type, including osteoblasts, tenocytes, endothelial cells and chondrocytes. Furthermore, it has proved effective in clinical applications relating to bone and wound healing and myocardial ischaemia. Until now, no studies have been performed regarding the effects of ESWT on regeneration of peripheral nerve injuries in humans.

Inclusion Criteria:

• complete lossless transection of one or more digital nerves distal to the branching out of the commune median or ulnar nerves
• direct, tension-free coaptation of the nerve stumps

Exclusion Criteria:

• segment loss of the nerve
• tension after direct coaptation
• diabetic neuropathy or other peripheral neuropathies
• other disease with reduced sensibility of the fingers
• injuries in the course of the nerve (plexus brachialis, median or ulnar nerve)
• chronic inflammatory disease
• rheumatoid arthritis
• pregnancy
• patients not able to give written consent
• patients with an implantable cardiac defibrillator or pacemaker
• patients which are sensitive to electromagnetic radiance

The participant will be wearing an acoustic and visual masking. The outcome assessor won't know if the participant was treated or if he was assigned to the sham group.