Relative efficacy of transcranial motor evoked potentials, mechanically-elicited electromyography, and evoked EMG to assess nerve root function during sustained retraction in a porcine model.

摘要: STUDY DESIGN This is an animal experiment using transcranial motor evoked potentials (TcMEP), mechanically elicited electromyography (EMG), and EMG during spinal nerve root retraction in a pig model. OBJECTIVE To compare the sensitivity of these 3 electrophysiological measures for constant force applied to isolated lumbar specific duration time. SUMMARY OF BACKGROUND DATA The incidence injury spine surgery ranges from 0.2% 31%. Direct roots may cause injuries, but amount that safely be not clear. Using established porcine model, we examined changes occurring multimyotomal TcMEPs, EMGs, EMGs continuous at over 10 minutes. METHODS TcMEP, EMG, responses were recorded tibialis anterior (TA) muscle experiments. dominant innervating TA was determined with EMG; preretraction TcMEP stimulation threshold (NRT) obtained. retracted 2 Newton (N) trials every minute retraction. NRT measured immediately after minutes recovery. RESULTS.: During N, amplitude progressively decreased all highly significant curvilinear fashion. mean 59% +/- 14% baseline values. N rose 1.8 0.7 mA (P < 0.01 vs. baseline). increase strongly correlated decrease (R = 0.90, P 0.001). activity variable; tonic observed only (20%). CONCLUSION Three electrophysiologic methods used intraoperatively assess neural function single root. Retraction produced consistent TcMEPs EMG. These show promise assessing limits on surgery. Mechanically sensitive