Chronic pain is a well-known complication after surgery, but the prevalence of persistent pain after upper extremity surgery or other trauma affecting the radial, ulnar or the medial nerve, or branches of these nerves such as digital nerves is unknown. The reason that some patients develop persistent neuropathic pain after surgery, while others, who have been through the exact same procedure or trauma, are pain free is still unknown. The underlying mechanisms are still largely unknown. This can lead to different responses to treatment. Whenever possible, it is important to identify and address the underlying pain mechanisms in the individual patient in order to design an optimal treatment.