Has postoperative pain been eradicated?

Abstract

Recent evidence suggests that surgical trauma induces a process of central nervous system sensitisation that contributes to and enhances postoperative pain. These changes are also thought to be the underlying cause of much chronic pain. Central sensitisation is generated not only during surgery, but also postoperatively as a result of the inflammatory response to the damaged tissue. This knowledge provides a rational basis for pro-active, pre-emptive and postoperative analgesic strategies to reduce the neuronal barrage associated with tissue damage. Reduction or elimination of postoperative pain is therefore possible. We advocate the use of continuous extrapleural intercostal nerve block for postoperative analgesia in patients undergoing thoracotomy. When this is begun pre-emptively (by precutaneous, pre-incisional paravertebral block) it is combined with an opiate and a non-steroidal anti-inflammatory drug premedication. In a randomised study of 56 patients, pain scores of less than 0.5 cm on a 10 cm scale were produced, postoperative lung function was preserved and glucose and cortisol responses were significantly unchanged from preoperative values. Evidence that effective perioperative analgesia reduces the incidence of chronic post-thoracotomy chest wall pain was found in a retrospective study of 1000 consecutive thoracotomies. The endpoints of a zero pain score, complete preservation of preoperative lung function and prevention of the stress response to trauma are currently achievable and should be provided for virtually all patients undergoing chest surgery. Pre-empting pain must be the goal for all those involved in the postoperative care of patients.