Peripheral nerve injuries are devastating injuries, which can lead to severe disability. Nerve injuries are relatively common. It occurs with up to 3% of all patients admitted to Level I trauma centers. Most of the injuries to peripheral nerves occur in the upper extremities. Nerve injury will lead to significant impairment in motor function and causes sensory loss. Depending on the level of nerve injury the consequences can be devastating and have great impact on a patient’s life and ability to perform daily activities such as work and hobbies. Nerve injury not only causes physical disability. There is evidence it also has great consequences psychologically. Cognitive, emotional and behavioral aspects influence recovery. It is important these factors are recognized so that the quality of patient care can be improved. The last decades both experimental and clinical research has been focused on optimizing the reconstruction of nerve injuries. The studies in this thesis are focused on the optimization of nerve reconstruction.