Chronic pain after surgery: pathophysiology, risk factors and prevention.

Interest in chronic pain after surgery has grown since the finding that more than a fifth of patients attending chronic pain clinics cite surgery as the cause for their chronic pain. The problem is not limited to major surgery; even common minor procedures such as hernia repair have a significant risk of chronic pain. Surgical technique can influence the development of chronic postsurgical pain (CPSP) and techniques to minimise nerve injury should be used where possible. Central nervous system changes contribute to the development of persistent pain following surgical trauma and nerve injury. Pharmacological agents that interrupt the mechanisms contributing to central sensitisation may be helpful in reducing the incidence of CPSP. Psychosocial factors are also important in the development of chronic pain and should be addressed as part of a holistic approach to perioperative care.