From pain research to pain treatment: role of human pain models.

There is no objective measure of pain; we can however measure different aspects of the pain perception. Earlier experimental pain models often only involved induction of cutaneous pain. Recently new experimental models have been developed eliciting deep muscle and visceral pain that may more closely resemble the clinical pain condition. It is imperative to use multi-modal and multi-structure pain induction and assessment techniques, as a simple model cannot describe the very complex and multi-factorial aspects of clinical pain. The importance of peripheral and central hyperexcitability for acute and chronic pain has been demonstrated in animals and to some extent in humans. But in spite of our immense knowledge we still do not know how to prevent and treat this hyperexcitability. Our understanding of nociceptive mechanisms involved in acute and chronic pain and the effects of anaesthetic drugs or combinations of drugs on these mechanisms in humans may also be expanded with experimental human models. This knowledge can then help us to develop and test therapeutic regimes in patients with acute and chronic pain.