[Intracerebral neurosurgery in the treatment of chronic pain].

Brain surgery is generally considered a treatment of last resort for chronic pain resistant to all other therapeutic measures. The neurosurgical treatment of pain may be either destructive (e.g., thalamotomy) or augmentative (e.g., electrical stimulation through an electrode connected to an implanted neurologic pacemaker). For pain of the neurogenic type (neuropathic or deafferentation pain), the preferred target is either the sensory nucleus of the thalamus, at a site corresponding somatotopically to the location of the pain, or the precentral cortex. For somatic (nociceptive) pain, stimulation of the periventricular or periaqueductal gray matter, or intraventricular infusion of morphine, may be useful. These operations are now indicated only in exceptional cases, as will be explained with reference to the author's long experience.