[Low dose morphine epidural anaesthesia. Diagnostic and prognostic interest. 492 cases (author's transl)].

Low dose morphine epidurals (0.5 to 4 mg) provide a good way of controlling either per or postoperative pain (210 cases) or chronic, somatic, intractable pain (282 cases). Selective and metameric medullar hypoalgesia is induced at a level which varies with the level of injection. There is an acquired tolerance which restricts the use of such injections to the short-term monitoring of somatic pain. In other types of psychogenic and deafferentiation pain, there is little or no sedation, but there are maximum secondary dysphoric effects. The degree of combination of these dysphoric effects with hypoalgesia is of diagnostic interest of the type of pain involved, and of prognostic interest when both somatic and deafferentation pains are present.