Electrostimulation and neurosurgical measures in cancer pain.

Neurosurgery for cancer pain may always be considered when the pain no longer responds to conservative treatment methods or only at the cost of undesirable side-effects. Almost all these operations that can be considered for the cancer patient can be performed percutaneously, without general anaesthesia, without loss of blood, and with short hospitalization. Chronic pain has to be differentiated according to whether it is somatogenic or neurogenic. For somatogenic pain (pain without any neurological deficit), intrathecal or intraventricular administration of morphine-like substances through an implanted drug delivery system is the most attractive method. The classical neurosurgical interruption of a tract conducting pain between the periphery and the cerebral integration centers is an almost obsolete method, and percutaneous cordotomy can only be discussed when the pain is strictly unilateral and the prognosis of the disease relatively favorable. For neurogenic pain (pain with sensory disturbances) the only method which can be helpful is electrical stimulation with an implanted neuropacemaker connected to an electrode in the dorsal columns of the cord or in the sensory thalamic nucleus (depending on the location of the pain), since morphine has at best only a poor analgesic effect on deafferentation pain.