[Use of cortical somatosensory evoked potentials in surgical treatment of AVMs in and around the central sulcus].
Electric potentials named N1, P2 are recorded from electrodes on the primary sensory cortex when the contralateral median nerve is electrically stimulated transcutaneously at the wrist. N1 is negative wave about 20 msec in peak latency, derived from cortex area 3b, and P2 is positive wave about 24 msec in peak latency, elicited from area 1 and 2. These components will show phase reversals between two responses recorded from precentral and postcentral electrodes pairs. In this report, we attempted to recognize central fissure in 4 cases of arteriovenous malformation in sensorimotor cortex with the benefit of the intraoperative cortical SEPs. We obtained successful recording of phase reversal and identified central fissure in all cases, to whom several anesthetic agents which were said to affect SEP in latency and amplitude were administered continuously during operation. Electrophysiologically recognized central fissures did not coincide with central sulcus arteries those identified by angiographic measurements of two patients. Avoiding injury to the motor cortex, 3 AVMs were completely resected without causing additional neurological deficits. One case whose nidus was hidden into the motor cortex was given up for its resection. In this case the clipping of feeding vessels was chosen for the treatment. Direct monitoring of SEP gives us many additional informations to radiological landmarks concerning the place of sensorimotor cortex and the selection of the surgical approach to the paracentral lesion.
Takenobu
A
A
Department of Neurosurgery, Tottori University School of Medicine, Yonago, Japan.
Watanabe
T
T
Hori
T
T
D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000503:physiopathology*; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000503:physiopathology / Q000601:surgery*; D007430:Intraoperative Care; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology; D013003:Somatosensory Cortex / Q000503:physiopathology