Higher success rate with transcranial electrical stimulation of motor evoked potentials using constant-voltage stimulation compared with constant-current stimulation in patients undergoing spinal surgery

Publication date: Available online 5 May 2017
Source:The Spine Journal
Author(s): Hideki Shigematsu, Masahiko Kawaguchi, Hironobu Hayashi, Tsunenori Takatani, Eiichiro Iwata, Masato Tanaka, Akinori Okuda, Yasuhiko Morimoto, Keisuke Masuda, Yuu Tanaka, Yasuhito Tanaka
Background ContextDuring spine surgery, the spinal cord is electrophysiologically monitored via transcranial electrical stimulation motor evoked potentials (TES-MEP) to prevent injury. TES-MEP involves the use of either constant-current or constant-voltage stimulation; however, there are few comparative data available regarding their ability to adequately elicit compound motor action potentials (CMAPs). We hypothesized that the success rates of TES-MEP recordings would be similar between constant-current and constant-voltage stimulation in patients undergoing spine surgery.PurposeTo compare the success rates of TES-MEP recordings between constant-current and constant-voltage stimulation.Study DesignProspective.Patient SampleData from 100 patients undergoing spinal surgery at the cervical, thoracic, or lumbar levels were analyzed.Outcome MeasuresThe success rates of the TES-MEP recordings from each muscle were examined.MethodsTES with constant-current and constant-voltage stimulation at the C3 and C4 electrode positions (international "10–20" system) were applied to each patient. CMAPs were bilaterally recorded from the abductor pollicis brevis (APB), deltoid (Del), abductor hallucis (AH), tibialis anterior (TA), gastrocnemius (GC), and quadriceps (Quad) muscles.ResultsThe success rates of the TES-MEP recordings from the right Del, right APB, bilateral Quad, right TA, right GC, and bilateral AH muscles were significantly higher using constant-voltage stimulation than they were with constant-current stimulation. The overall success rates with constant-voltage and constant-current stimulation were 86.3% and 68.8%, respectively (risk ratio 1.25[95% CI: 1.20–1.31]).ConclusionsThe success rates of TES-MEP recordings were higher using constant-voltage stimulation compared with constant-current stimulation in patients undergoing spinal surgery.



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