Abstract
A new method of intraoperative localisation of the primary motor cortex is described, based on the application of single anodal electric pulses to the brain surface. Patients were anaesthetised with propofol infusion, and neuromuscular blockade was temporarily alleviated to allow recording of surface EMG responses (CMAPs) to the stimuli. Primary motor areas could be localised in 18/19 patients studied. In the other patient, no responses were elicited, as the operative field was posterior to the motor cortex. When compared with MEPs elicited in awake patients by magnetic stimuli, responses to intraoperative anodal stimulation were of small amplitude (usually less than 10% of MEPs) and their latency was some 1 to 2 ms longer. One month after the operation, only 1/19 patients was left with a slight muscle weakness, although seven showed preoperative motor deficit. The procedure proved easy and fast, needing no preliminary surgery or time consuming preparation. It did not induce any detectable side effects.
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- Ebeling U., Schmid U. D., Ying H., Reulen H. J. Safe surgery of lesions near the motor cortex using intra-operative mapping techniques: a report on 50 patients. Acta Neurochir (Wien) 1992;119(1-4):23–28. doi: 10.1007/BF01541777. [DOI] [PubMed] [Google Scholar]
- Jellinek D., Jewkes D., Symon L. Noninvasive intraoperative monitoring of motor evoked potentials under propofol anesthesia: effects of spinal surgery on the amplitude and latency of motor evoked potentials. Neurosurgery. 1991 Oct;29(4):551–557. doi: 10.1097/00006123-199110000-00011. [DOI] [PubMed] [Google Scholar]
- Kido D. K., LeMay M., Levinson A. W., Benson W. E. Computed tomographic localization of the precentral gyrus. Radiology. 1980 May;135(2):373–377. doi: 10.1148/radiology.135.2.7367629. [DOI] [PubMed] [Google Scholar]
- PHILLIPS C. G., PORTER R. Unifocal and bifocal stimulation of the motor cortex. J Physiol. 1962 Aug;162:532–538. doi: 10.1113/jphysiol.1962.sp006948. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taniguchi M., Nadstawek J., Langenbach U., Bremer F., Schramm J. Effects of four intravenous anesthetic agents on motor evoked potentials elicited by magnetic transcranial stimulation. Neurosurgery. 1993 Sep;33(3):407–415. doi: 10.1007/978-3-642-78801-7_46. [DOI] [PubMed] [Google Scholar]
- Uematsu S., Lesser R., Fisher R. S., Gordon B., Hara K., Krauss G. L., Vining E. P., Webber R. W. Motor and sensory cortex in humans: topography studied with chronic subdural stimulation. Neurosurgery. 1992 Jul;31(1):59–72. doi: 10.1227/00006123-199207000-00009. [DOI] [PubMed] [Google Scholar]
- Wood C. C., Spencer D. D., Allison T., McCarthy G., Williamson P. D., Goff W. R. Localization of human sensorimotor cortex during surgery by cortical surface recording of somatosensory evoked potentials. J Neurosurg. 1988 Jan;68(1):99–111. doi: 10.3171/jns.1988.68.1.0099. [DOI] [PubMed] [Google Scholar]