Please confirm that an ethics committee approval has been applied for or granted: Not relevant

Background and Aims Background and aims Transcutaneous electrical nerve stimulation (TENS) is an established technique for pain management. There is evidence that stimulation delivered through a dome-shaped electrode is associated with improved clinical outcomes compared with conventional flat patch electrodes currently utilized in TENS, due to a greater depth and area of electrical stimulation. The aim was to investigate this using computational modelling analysis

Methods Methods A 3D finite element model of cutaneous tissue coupled with an active model of nerve fiber was developed, for simulation of E-fields originating from various electrode geometries and stimulation configurations. Outputs from the tissue model were transferred into the nerve model to determine the minimum currents required to activate cutaneous fibers. The efficacy was based on the level of activation of Aβ, Aδ and C fibers.

Results Results Dome-shaped electrodes required significantly lower device current to activate nerve fibers compared with flat TENS electrodes. The depth of electrical stimulus was 4x greater and the area of field activation 40% greater. The maximum amplitude was 40x higher with the dome shaped electrode compared to TENS electrodes at depths < 2 cm. The dome-shaped electrode could activate large nerves at up to ~1 cm depth with current < 30 mA, whilst TENS could only do so at < 0.25 cm.

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Abstract EP067 Figure 1

Activating functions (AF) extracted from the undeformed tissue model at I = 1 mA. (left) AF distribution for modelled electrode configurations in an axial plane; (right) AF distribution vs coordinate extracted from the line at 1 cm depth (marked red)

Conclusions Conclusion A dome-shaped electrode appears to recruit more nerves at the same level of stimulating current due to its greater depth of penetration and activation field compared with conventional TENS. This may equate with improved pain and functional outcomes for patients.