Corticobulbar motor evoked potentials from tongue muscles used as a control in cervical spinal surgery

• Published in: Clinical neurophysiology practice 2017-01, Vol.2, p.124-129
• Main Authors: Kim, Dong-Gun, Jo, Seong-Rae, Youn, Minjung, Hyun, Seung-Jae, Kim, Ki-Jeong, Jahng, Tae-Ahn, Kim, Hyun-Jib, Park, Kyung Seok
• Format: Article
• Language: English
• Subjects: Clinical and; Corticobulbar MEPs; Corticospinal tract; Hypoglossal nerve; Intraoperative neurophysiological monitoring; Motor-evoked potential
• ISSN: 2467-981X; 2467-981X
• DOI: 10.1016/j.cnp.2017.05.003

•The corticobulbar MEPs from tongue muscles were successfully elicited from 96% of the tested patients.•Corticobulbar MEPs from tongue muscles were monitorable from the baseline in 92% of the tested hypoglossal nerves.•Corticobulbar MEPs from the tongue muscle might be useful as controls in cervical spine surgery. Motor evoked potentials (MEPs) changes might be caused to the non-surgically induced factors during cervical spinal surgery. Therefore, control MEPs recorded cranially to the exit of the C5 root are highly recommendable in cervical spinal surgery. We studied whether corticobulbar MEPs (C-MEPs) from tongue muscle could be used as a control MEPs in cervical spinal surgery. Twenty-five consecutive cervical spinal surgeries were analyzed. Stimulation of motor area for tongue was done by subcutaneous electrodes placed at C3/C4 (10–20 EEG System), and recording was done from both sides of tongue. C-MEPs were recorded successfully 24 out of the 25 (96%) tested patients. Forty-six out of fifty MEPs (92%) from tongue muscles were monitorable from the baseline. In two patients, we could obtain only unilateral C-MEPs. Mean MEPs latencies obtained from the left and right side of the tongue were 11.5±1ms and 11.5±0.8ms, respectively. Monitoring C-MEPs from tongue muscles might be useful control in cervical spinal surgery. They were easily elicited and relatively free from phenomenon of peripheral stimulation of the hypoglossal nerves. This is first study to identify the usefulness of C-MEPs as a control of cervical spinal surgery.