engleski

ntraoperative changes of muscle motor evoked potentials in patient with intramedullar cervicospinal tumor- the case report.

Introduction: Intraoperative MEPs and SSEPs are standardly performed to avoid motor and sensory pathway lesions in spinal surgery Material and Methods: Patient, male, 19 years, with recently worsened quadriparesis. MRI: intramedullar spinal tumor expanding from C2 to C7 spinal level. Intraoperative neuromonitoring was performed: SSEPs, spinal D wave, and muscle motor evoked potentials (MMEPs). Results: For monitoring of corticospinal pathway functions we used transcranial electrical stimulation (C3-C4/C4-C3), monopolar, anodal, with train of five stimuli, pulse width 0.5ms, interstimulus interval 4ms, and a train repetition rate of 2Hz. Baseline thresholds of MMEPs were identified: for both hand/forearm muscles after using stimulation intensity of 95 mA, and for both leg/foot muscels after using intensity of 175 mA. During the tumor resection, in order to have real time information about functional integrity of corticospinal tract, monitoring focused on D wave, and MMEPs was performed. The dorsal column sensory pathways were monitored by n. medianus and n. tibialis bilaterally SSEPs. There were no changes in baseline values of SSEPs, and the amplitude of epidural-recorded D wave was stabile. During the final part of tumor resection we found gradual rise of MMEP amplitude in all, especially right hand and foot muscles, without the significant alteration in the morphology of the recorded MMEPs. After the tumor resection and before closing, all monitored modalities were tested again. We confirmed the rise in MMEP amplitudes, elicited with the baseline stimulation intensity values, and the unchanged baseline recordings of all other monitored evoked potentials. Patient recovered entirely from his preoperative motoric deficit. Conclusion: Increase of MMEPs amplitudes in our patient during and after the tumor resection was the good predictor of his postoperative motor functions recovery.

intraoperative neurophysiology; spinal tumors

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