The Effect Of Tetanic Stimulation Of Peripheral Nerve On Motor-evoked Potentials

The effect of tetanic stimulation of peripheral nerve on motor-evoked potentialsPARTâ… The effect of tetanic stimuulation of peripheral nerve on direct motor-evoked potentialsBackgroundCurrently MEP is more and more widely used. Neuromuscular blockade can suppress myogenic motor evoked potentials. Some researchers reported that tetanic stimulation (Ts) of the peripheral nerve before intraoperative transcranial stimulation may enhance myogenic MEP during neuromuscular blockade. In the current study, we evaluated whether tetanic stimulation of the peripheral nerve can also augment amplitudes of intraoperative direct MEP.MethodsEight patients undergoing elective brain surgery under propofol-fentanyl anesthesia with partial neuromuscular blockade were enrolled in the study. Both conventional MEP(C-MEP) and posttetanic MEP(P-MEP) monitoring were accomplishd throughout the operation in each patient. For C-MEP recording, direct electrical train of five pulses stimulation with an interstimulus interval of 2 milliseconds was delivered to motor cortex, and the compound muscle action potentials were unilaterally recorded from the abductor pollicis brevis and tibialis anterior. For P-MEP recording, tetanic stimulation (50Hz,50mA of stimulus intensity) with a duration of 5s was applied to the contralateral tibial nerve 1s before direct stimulation. Recording of compound muscle action potentials were performed in the same manner as C-MEP recording. Randomized crossover method was employed to each C-MEP and P-MEP. The interval was 120 seconds. ResultsAmplitudes of P-MEP from the abductor pollicis brevis and tibialis anterior were significantly larger compared with those of C-MEP (P<0.05). Three patients had body movements during intraoperative direct MEP. Other patients had no electrical stimulation and anesthesia-related complications.ConclusionIn patients under propofol and fentanyl anesthesia with partial neuromuscular blockade, the application of tetanic stimulation of the peripheral nerve before intraoperative direct stimulation can enlarged the amplitudes of MEP from the abductor pollicis brevis and tibialis anterior. Ts of the peripheral nerve can be intraoperatively applied as a method to augment myogenic MEP responses. PARTâ…¡The effect of tetanic stimulation of peripheral nerve on transcranial motor-evoked potentialsObjectiveTo evaluate the effects of tetanic stimulation of the peripheral nerve on amplitudes of MEP from the peripheral and facial nerve.MethodsThirty patients under propofol-fentanyl anesthesia with partial neuromuscular blockade were enrolled in the study. Both C-MEP and P-MEP monitoring were accomplishd throughout the operation in each patient. For C-MEP recording, transcranial electrical train of three pulses stimulation with an interstimulus interval of 2 milliseconds was delivered to C3-4, and the compound muscle action potentials were unilaterally recorded from the abductor pollicis brevis, orbicularis oculi and orbicularis oris. For P-MEP recording, tetanic stimulation (50Hz, 50mA of stimulus intensity)with a duration of 5s was applied to the ipsilateral ulnar nerve and contralateral tibial nerve 1s before transcranial stimulation. Recording of compound muscle action potentials were performed in the same manner as C-MEP recording. Randomized crossover method was employed to each C-MEP and P-MEP. The interval was 120 seconds.ResultsThe application of Ts of the ulnar nerve and tibial nerve significantly enlarged the success rates of MEP recording from the abductor pollicis brevis compared with those without Ts (P<0.05). Success rates of MEP recording from the orbicularis oculi and orbicularis oris were similar with those of C-MEP when Ts was applied to the ulnar nerve and tibial nerve (P>0.05).The application of Ts of the ulnar nerve and tibial nerve significantly enlarged the amplitudes of MEP from the abductor pollicis brevis compared with those without Ts (P<0.05). Amplitudes of P-MEP from the orbicularis oculi were similar with those of C-MEP when Ts was applied to the ulnar nerve and tibial nerve (P>0.05). Amplitudes of P-MEP from the orbicularis oris were similar with those of C-MEP when Ts was applied to the ulnar nerve and tibial nerve (P>0.05).All patients had no electrical stimulation and anesthesia-related complications.ConclusionIn patients under propofol and fentanyl anesthesia with partial neuromuscular blockade, the application of tetanic stimulation of the peripheral nerve before transcranial stimulation can enlarged the amplitudes of MEP from the abductor pollicis brevis. The amplitudes of MEP of the facial nerve have no change.