THE USEFULNESS OF SUBCORICAL MONITORING USING MEP FOLLOWING CORTICAL OR TRANSCRANIAL ELECTRICAL STIMULATION IN THE OPERATION OF THE CEREBRAL LESIONS NEAR THE PYRAMIDAL TRACT OR THE CENTRAL SULCUS
Abstract number :
2.460
Submission category :
Year :
2003
Submission ID :
2228
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Yasukazu Kajita, Satoshi Maesawa, Naotaka Usui, Otone Endoh, Jun Yoshida Neurosurgery, Nagoya University, Graduate School of Medicine, Nagoya, Aichi, Japan
Surgery for resection of the lesions around the central sulcus or pyramidal tracts carries an associated risk of causing significant motor deficits. The use of motor evoked potential (MEP) monitoring following the cortical or transcranial electrical stimulation allows these lesions to be removed with maximal safety and efficacy.
In forty patients with cerebral lesions adjacent to the central lesions, the surgical resection was performed. In eight cases with the deep-seated lesions, we oriented the scalp stimulation site just over the primary motor area using the neuronavigation. The stimulation at the condition (200-250V, 500Hz, 0.2ms,3-5trains) was transcranially applied. In thirty-two cases with the lesions around the central sulcus, after craniotomy, central sulcus was determined by N20 phase reversal on sensory evoked potential (SEP) recording following the median nerve stimulation. Cortical motor mapping was performed by monopolar anodal stimulation with a train of 500Hz (3-5 pulses) (stimulation intensity 8-25 mA). Action potentials were recorded from facial, thenar, biceps arm and quadriceps femoralis muscles. MEP recording continued for the intra-operative monitoring of the motor system until radical lesion resection was macroscopically achieved.
No new postoperative motor deficits were seen in 95% of the patients in this series.
Subcortical MEP monitoring enhanced the safety of the operation of lesion resection near the pyramidal tract or the central sulcus.