NEUROSURGICAL APPLICATIONS FOR INTRAOPERATIVE STIMULATION

Abstract

Intraoperative neurostimulation can be most useful to the surgeon whenever the need arises to assess physiological function or identify fiber pathways and/or neuronal populations in critical areas of brain, spinal cord, or peripheral nerve. Low-level (threshold) stimulation allows for the nearest populations of axons or neuronal cell bodies (in the vicinity of the electrode tip) to be activated in the safest possible fashion. When motor pathways are being tested, attention must be paid to the control and administration of muscle relaxant drugs, which can dampen or abolish muscle responsiveness during stimulation. Peripheral nerve conduction studies can be carried out intraoperatively and may be beneficial for assessing the physiological status of a section of traumatized nerve. Cortical mapping is valuable when surgical resections near motor or speech areas in the brain are contemplated and may help the surgeon avoid significant postoperative deficits in movement or language. Intraoperative stimulation for identifying spinal motor pathways may be used to guide surgical exploration. Finally, selective intraoperative stimulation for identifying nerve fibers encased in tumor may be useful for procedures involving difficult dissections along the brachial plexus or other major nerves in the arm or leg.