Ms120b

An MS120B (Nihon-Kohden, Tokyo, Japan) was used to perform transcranial stimulation, with parameters of 5 stimuli in a row at 2-ms intervals, a constant biphasic current of 200 mA for 500 μs, a 50–1000-Hz filter, and a 100-ms epoch time with ≤20 recorded signal responses. The stimulated point was 2 cm anterior and 6 cm lateral from the Cz location over the cerebral cortex motor area. Using a Neuromaster MEE-1232 ver. 05.10 (Nihon-Kohden), which is expandable to 32 channels, muscle action potentials were recorded from the upper and lower extremities via a pair of needle electrodes that were 3–5 Tc-MsEPs apart. The bilateral trapezius, triceps, deltoid, biceps, brachioradialis, abductor digit minimi, extensor carpi ulnaris, adductor longus, quadriceps femoris, hamstrings, tibialis anterior, gastrocnemius, and abductor halluces were used as target muscles. From April 2009 to August 2010, we used 2-channel plug-surface electrodes for the EAS for consecutive patients, and from September 2010 to December 2011, we used bilateral pairs of needle electrodes that were 2 cm apart outside the anus for consecutive patients (Fig. 1). Tc-MsEP data from these muscles were used for analysis.

A MS120B (Nihon Kohden, Tokyo, Japan) was used to perform transcranial stimulation. The stimulation parameters were 5 stimuli in a row at 2-ms intervals, a constant biphasic current of 200 mA for 500 μs, a 50-1000 Hz filter, and a 100-ms epoch time with ≤20 recorded signal responses. The stimulated point was 2 cm anterior and 6 cm lateral from the Cz location over the cerebral cortex motor area. Using the Neuromaster MEE-1232 ver. 05.10 (Nihon Kohden, Japan), which is expandable to 32 channels, muscle action potentials were recorded from the upper and lower extremities via a pair of needle electrodes 3 to 5 Tc-MsEPs apart. The bilateral trapezius, triceps, deltoid, biceps, brachioradialis, abductor digit minimi, extensor carpi ulnaris, adductor longus, quadriceps femoris, hamstrings, tibialis anterior, gastrocnemius (GC), and abductor halluces (AH) were used as target muscles. For anal sphincter muscles, a 2-channel surface plug-type electrode was applied to the EAS (Figure 1). Tc-MsEP data from these muscles were used for analysis. Multimodal monitoring was used in all cases, with a particular combination of brain stimulated spinal cord evoked potentials (D-wave) and somatosensory evoked potentials. Free running electromyography (EMG) from all the above muscles was monitored throughout the operation.