FES is a common and established method in the rehabilitation of persons with spinal cord injury (SCI). Some known effects of FES were investigated in several studies e.g. avoiding disuse and denervation atrophy, improving muscle force, power output and endurance changing muscle fibre type, increasing cross sectional area of muscle, increasing muscle mass, activation of nerve sprouting, reducing spasticity and motor learning. Most of the studies investigated the impact of FES in the lower limbs. For the upper extremities fewer studies exist. However, it is supposed that the effects of FES are similar. In the rehabilitation of persons with tetraplegia, FES, especially the stimulation of the upper extremities triggered by electromyography (EMG) is an established method to generally improve hand and arm function. However, none of those studies has investigated the effect of FES in combination with reconstructive tetraplegia hand surgery. Improved muscle strength is supposed to improve the functional outcome in participation. Additionally, FES could increase the motor learning process. Supported by the clinical observation we hypothesize that FES has a positive influence on the outcome of surgical reconstruction of tendon and/or nerve transfers.