Abstract
Purpose: Repetitive transcranial electrical stimulation (rTES) was used to activate descending output to the external urethral sphincter muscle. Methods: Motor evoked potentials (MEPs) were recorded from external urethral sphincter (EUS), and anterior tibial (TA) muscles following high voltage rTES in 9 consecutive patients undergoing spine surgery. Anesthesia was achieved by continuous propofollnarcotic infusion without paralytic agents. Anodal cortical stimulation was delivered at C4/C3, C2/C1, and Cz/Fz locations in each patient. Latency and amplitude of the MEP was measured and compared for each bipolar stimulation montage. Results: The mean latency was 20.24 ± 1.3 msec. for Cz/Fz; 20.19 ± 1.1 msec. for C4/C3 and 20.19 #± 1.1 msec. for C2/C1. Statistical analysis showed no significant difference in latency between the three sites (F(2,15) = 0.004; p > 0.05). The mean amplitude was 3 7.14 ± 24.3 μV for Cz/Fz; 113.33 ± 100.6 μV for C4/C3; and 85 ± 73.9 μV for C2/C1. A significant difference between the amplitudes at three sites was observed (F(2,8) = 5.2; p < 0.05). The amplitude at C4/C3 was significantly greater than amplitude at Cz/Fz (t (8) = 3.08; p < 0.05), but data did not give enough evidence to believe that difference between amplitudes for site C4/C3 & C2/C1 was significant (p > 0.05). Conclusions: This study shows that the intraoperative MEP monitoring of the EUS is a feasible method. Furthermore, activation of descending axonal outflow to the EUS muscle is best achieved by cortical stimulation directed from C4 to C3 or C2 to C1 points.
Original language | English (US) |
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Pages (from-to) | 343-348 |
Number of pages | 6 |
Journal | Electromyography and Clinical Neurophysiology |
Volume | 46 |
Issue number | 6 |
State | Published - Nov 2006 |
Keywords
- Cortical localization
- External urethral sphincter
- Motor evoked potential
- Transcranial electrical stimulation
ASJC Scopus subject areas
- Physiology
- Clinical Neurology
- Physiology (medical)