title: Augmentation of motor evoked potentials using multi-train transcranial electrical stimulation in intraoperative neurophysiologic monitoring during spinal surgery.
abstract: Transcranial motor evoked potentials (TcMEPs) are widely used to monitor motor function during spinal surgery. Improvements in transcranial stimulation techniques and general anesthesia have made it possible to record reliable and reproducible potentials. However, TcMEPs are much smaller in amplitude compared with compound muscle action potentials (CMAPs) evoked by maximal peripheral nerve stimulation. In this study, multi-train transcranial electrical stimulation (mt-TES) was introduced to enhance TcMEPs, and the optimal setting of mt-TES was investigated. In 30 patients undergoing surgical correction of spinal deformities (4 males and 26 females with normal motor status; age range 11-75 years), TcMEPs from the abductor hallucis (AH) and quadriceps femoris (QF) were analyzed. A multipulse (train) stimulus with an individual pulse width of 0.5 ms and an inter-pulse interval of 2 ms was delivered repeatedly (2-7 times) at different rates (2, 5, and 10 Hz). TcMEP amplitudes increased with the number of train stimuli for AH, with the strongest facilitation observed at 5 Hz. The response amplitude increased 6.1 times on average compared with single-train transcranial electrical stimulation (st-TES). This trend was also observed in the QF. No adverse events (e.g., seizures, cardiac arrhythmias, scalp burns, accidental injury resulting from patient movement) were observed in any patients. Although several facilitative techniques using central or peripheral stimuli, preceding transcranial electrical stimulation, have been recently employed to augment TcMEPs during surgery, responses are still much smaller than CMAPs. Changing from conventional st-TES to mt-TES has potential to greatly enhance TcMEP responses.
authors: Department of Orthopaedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8510, Japan, stsutsui1116@gmail.com.
authors: Shunji
authors: S
authors: Tsutsui
authors: Hiroshi
authors: H
authors: Iwasaki
authors: Hiroshi
authors: H
authors: Yamada
authors: Hiroshi
authors: H
authors: Hashizume
authors: Akihito
authors: A
authors: Minamide
authors: Yukihiro
authors: Y
authors: Nakagawa
authors: Hideto
authors: H
authors: Nishi
authors: Munehito
authors: M
authors: Yoshida
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000771:Anesthesia, Intravenous / Q000379:methods; D000777:Anesthetics / Q000008:administration & dosage; D002648:Child; D004566:Electrodes; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D013116:Spinal Cord / Q000601:surgery*; D013997:Time Factors; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D055815:Young Adult
chemical_list: D000777:Anesthetics