[Prevention and therapy of prolonged, chronic pain after surgery]

Prolonged, chronic pain after surgery is a very common phenomenon that has been underrecognized until recently. A number of risk factors and predictors (including the surgical procedure, age, gender, pre- and postoperative pain, psychosocial factors, genes and pain modulation variables) have been identified in the past years. Together with an increased knowledge about the pathophysiology of chronic pain after surgery, we may be able to develop successful drugs or interventions modifying the disease in subgroups of patients in the near future. However to date there is only little information about successful drugs or approaches which can be recommended to prevent chronic pain after surgery successfully. One of the reasons is the inadequacy of trial design and lack of prospective studies. Single RTCs show for example positive results with perioperative pregabalin for 30 days after total knee arthroplasty or short-term ketamine intravenously after open colon surgery. However, others have failed to show an effect after other procedures with similar drugs and treatment approaches. Positive results are consistently shown with regional anesthesia techniques perioperatively (for example epidural analgesia after thoracic surgery of paravertebral block after mastectomy). However, again, convincing evidence for certain treatment protocols (start and duration of regional anesthesia techniques) to get optimal results are limited at most. Thus, we are left with speculative effects after certain surgeries and may rely--at least to date--more on analgesic rather than disease related treatment approaches. Future studies with a standardized study design recognizing patient characteristics are highly needed to make progress and find drugs, strategies and approaches which can be applied to certain groups of patients to prevent the development of chronic pain after surgery successfully.