Comparison the waveform derivation of epidural spinal cord stimulation muscle evoked potentials (Sp-MEP) with transcranial electrical stimulation muscle evoked potentials (Tc-MEP): A preliminary study

• Published in: Journal of Spine Research Vol. 12; no. 12; pp. 1350 - 1355
• Main Authors: Suzuki, Hidenori, Nagao, Yuji, Sakai, Takashi, Funaba, Masahiro, Imajo, Yasuaki, Nishida, Norihiro
• Format: Journal Article
• Language: Japanese
• Published: The Japanese Society for Spine Surgery and Related Research 20.12.2021; 一般社団法人 日本脊椎脊髄病学会
• Subjects: intraoperative neuromonitoring; spinal cord stimulated motor evoked potentials; transcranial electrical stimulated motor evoked potentials; 硬膜外脊髄刺激筋誘発電位; 経頭蓋刺激筋誘発電位; 脊髄モニタリング
• ISSN: 1884-7137; 2435-1563
• DOI: 10.34371/jspineres.2021-1202

Introduction: The aim of this study was to compare the waveform derivation of epidural spinal cord stimulation muscle evoked potentials (Sp-MEP), which directly stimulate the spinal cord, with transcranial electrical stimulation muscle evoked potentials (Tc-MEP).Materials: Five patients who consented to intraoperative measurement of Sp-MEP were included in the study. In cervical spine disease, the derived muscles were deltoid, biceps, and adductor pollicis brevis (ADM) in the upper extremities, and quadriceps (Qc) and abductor hallucis longus (AH) in the lower extremities. In thoracic spine disease, ADM was used as a control in the upper extremities, and Qc, TA, and AH in the lower extremities. For epidural spinal cord stimulation, an epidural stimulation catheter was inserted into the lamina on the cranial side after decompression for 2-3 poles. The stimulation intensity was 15-20 mA for 10-15 consecutive stimulations, and the results obtained were averaged. In cervical spine disease, the upper limbs were deltoid, biceps, and ADM, and the lower limbs were Qc and AH. In thoracic spine disease, the lower limbs were Qc, TA, and AH. The amplitude values and amplitude ratios of Sp-MEP and Tc-MEP were compared in each derived muscle.Results: Sp-MEP showed greater amplitude increase than Tc-MEP in 11 of 46 muscles (23.9%). In 11 of 46 muscles (23.9%), deltoid was observed in 2 of 8 muscles (25%), biceps in 2 of 8 muscles (25%), ADM in 0 of 8 muscles, quadriceps in 4 of 10 muscles (40%), TA in 0 of 2 muscles (0%), and AH in 3 of 10 muscles (30%).Conclusions: At a maximum of 20 mA stimulation, Sp-MEP did not show an advantage for greater waveform derivation than Tc-MEP. For future cases, the stimulation intensity will be 20 mA to 30 mA and the data will be accumulated.