[Neurosurgical treatments of chronic pain].

During these last years the methods and the indications of analgesic neurosurgery have respectively changed toward greater multiplicity and more selectivity. The conservative methods of neurostimulation have acquired a prominent place in some types of pain from neuropathic origin. Their aim is to reinforce inhibitory fibre function. Whatever the technique used, stimulation of peripheral nerves, of posterior funiculi of the spinal cord, of the thalamus or the cerebral cortex, it will be effective only if the target structures are not totally, anatomically and functionally, destroyed. Intrathecal morphine administration, has been shown to be useful to control some cancer-induced pain. Lastly, the techniques of interrupting the pathways of pain, achieving greater selectivity in their effects, remain the preferred treatment for some types of localised pain having precise mechanisms.