One of the most exciting developments in medicine in this century has been the discovery of opioid receptors and their pharmacology. The breadth of know- edge derived from such discovery has truly changed the practice of medicine today. The acceptance by the clinicians of the research data obtained by the basic scientist on spinal opioids is truly amazing. The clinical sequelae of the discovery of opioid receptors has been the development of the technique of intraspinal administration of opioids. In the last decade much has been written about indications, effects, and side effects of...