Optimal parameters of transcranial electrical stimulation for intraoperative monitoring of motor evoked potentials of the tibialis anterior muscle during pediatric scoliosis surgery

• Published in: Neurophysiologie clinique Vol. 43; no. 4; pp. 243 - 250
• Main Authors: Azabou, E, Manel, V, Andre-obadia, N, Fischer, C, Mauguiere, F, Peiffer, C, Lofaso, F, Shils, J.L
• Format: Journal Article
• Language: English
• Published: Paris Elsevier SAS 01.10.2013; Elsevier; Elsevier Masson
• Subjects: Adolescent; Biological and medical sciences; Child; Children; Chirurgie de la scoliose; Electrodiagnosis. Electric activity recording; Enfants; Evoked Potentials, Motor - physiology; Female; Human health and pathology; Humans; Intraoperative neurophysiologic monitoring; Investigative techniques, diagnostic techniques (general aspects); Life Sciences; Male; Medical sciences; Monitoring, Intraoperative; Motor evoked potential; Muscle, Skeletal - physiology; Nervous system; Neurology; Paramètres de stimulation; Potentiel évoqué moteur; Pyramidal Tracts - physiology; Scoliosis - surgery; Stimulation parameters; Surveillance peropératoire neurophysiologique; Tissues and Organs; Transcranial Magnetic Stimulation - methods; Young Adult; Scoliosis surgery; Surveillance peropératoire neurophysiologique; Potentiel évoqué moteur; Enfants; Stimulation parameters; Intraoperative neurophysiologic monitoring; Motor evoked potential; Children; Paramètres de stimulation; Chirurgie de la scoliose; Human; Pediatrics; Nervous system diseases; Deformation; Spine; Diseases of the osteoarticular system; Electrophysiology; Intraoperative; Spine disease; Transcranial electrical stimulation; Osteoarticular system; Surveillance; Scoliosis; Surgery; Child; Monitoring
• ISSN: 0987-7053; 1769-7131
• DOI: 10.1016/j.neucli.2013.08.001

Summary Objective Transcranial electric stimulation elicited muscle motor evoked potentials (TESmMEPs) is one of the best methods for corticospinal tract's function monitoring during spine and spinal cord surgeries. A train of multipulse electric stimulation is required for eliciting TESmMEPs under general anaesthesia. Here, we investigated the best stimulation parameters for eliciting and recording tibialis anterior's TESmMEPs during paediatric scoliosis surgery. Patients and methods Numbers of pulses (NOP), inter-stimulus intervals (ISI) and current intensities allowing the best size tibialis anterior muscle's TESmMEPs under general anaesthesia, were tested and collected during 77 paediatric scoliosis surgery monitoring procedures in our hospital. Individual pulse duration was kept at 0.5 ms and stimulating electrodes were positioned at C1 and C2 (International 10-20-EEG-System) during all the tests. Results The NOP used for eliciting the best tibialis anterior TESmMEPs response was 5, 6, and 7 respectively in 21 (27%), 47 (61%) and 9 (12%) out of the 77 patients. The ISI was 2, 3 and 4 ms respectively in 13 (17%), 55 (71%) and 9 (12%) of them. The current intensity used varied from 300 to 700 V (mean: 448 ± 136 V). Conclusion Most patients had 6 as best NOP (61%) and 3 ms as best ISI (71%). These findings support that a NOP of 6 and an ISI of 3 ms should be preferentially used as optimal stimulation settings for intraoperative tibialis anterior muscle's TESmMEPs eliciting and recording during paediatric scoliosis surgery.