Neuromuscular Electrical Stimulation for Venous Thromboembolism Prophylaxis and Its Effects on Somatosensory-Evoked Potentials: A Pretrial Study of a New, U.S. Food and Drug Administration–Approved Device

Neuromuscular electrical stimulation (NMES) has emerged as a viable alternative for venous thromboembolism prophylaxis. Electrical stimulation of the peroneal nerve using NMES may potentially interfere with somatosensory-evoked potential (SSEP) acquisition. This feasibility study evaluates a NMES device and its effect on SSEP acquisition as an initial step in a randomized clinical trial to assess NMES for intraoperative venous thromboembolism prophylaxis. Healthy volunteers underwent SSEP testing during NMES in an outpatient setting. Concurrently, SSEP recordings of the posterior tibial nerve with stimulation at each ankle were obtained in 3 conditions: sham, NMES in place but inactive; ipsi, NMES active on leg ipsilateral to SSEP acquisition; and contra, NMES active on the leg contralateral to SSEP acquisition. Nonparametric statistical methods, including repeated measures, were used for data analysis. Stimulation intensities on the left, right, and bilaterally did not differ (P ≥ 0.20). Strong positive correlations were noted between the ipsilateral geko stimulus pulse width and ipsilateral SSEP stimulation intensities (left: rs = 0.866, P = 0.001; right: rs = 0.877, P = 0.001). Women required significantly greater pulse width settings than men (P = 0.01). Finally, visual inspection of waveforms, as used during dynamic IONM, did not show any significant variations of P37 cortical waveforms during NMES. As a preliminary step to testing NMES intraoperatively for venous thromboembolism prophylaxis, interference with SSEP acquisition was investigated in the outpatient laboratory setting. Within a small sample of healthy volunteers, no significant changes were seen in P37 cortical latencies to suggest interference between the NMES device and SSEP waveforms.