Neurosurgical Treatment of Cancer Pain

Abstract

Neurosurgery for cancer pain should always be considered when, in an advanced stage of the disease, the pain no longer responds to conservative treatment methods or only at the cost of undesired side effects. Appreciable progress has recently been achieved in this field. Almost all the operations that can be considered for the cancer patient can be performed percutaneously, without general anesthesia, without loss of blood, and with a short hospital stay. Parallel to the advances in the field of pain physiology, the neurosurgical therapeutic spectrum has also extended. In the choice of operation, it is of decisive importance to distinguish between deafferentation pain and somatic pain. Deafferentation pain is taken to mean pain in an area of disturbed sensitivity, as can be observed, e.g., after radiation damage to the brachial plexus. Somatic pain occurs because of irritation of pain receptors, for instance, bone pain in bone metastases. In accordance with this clinical pain classification, there are in principle two methods available for neurosurgery: (1) Interruption of the tracts conducting pain between the periphery and the cerebral integration centers. These are the destructive methods that are primarily considered in cases of somatic pain. (2) Intermittent electric stimulation of a tract or of a center aimed at producing inhibition of the pain information. These techniques are designated as neuroaugmentative, since here relief from pain is attained by stimulation of pain-inhibiting systems. These techniques are mainly used for treatment of deafferentation pain. A third (nondestructive) technique using a percutaneous approach consists of administration of opiates to the spinal cord via a catheter which can also be connected to a subcutaneously implanted reservoir.