Voltage between Electrodes as a Key Parameter in Oscillating Field Stimulation of Spinal Cord in Rat

The regeneration of injured spinal cord in applied weak DC electrical field has been demonstrated for years. However, the most suitable stimulating intensity has not been confirmed because the mechanism of axonal regeneration in applied DC electrical field is absent. This paper used finite element method to analyze the distribution of electrical field before and after injury and the uniformity of electrical field induced by different number of stimulating electrodes. Moreover, we improved the implantable oscillating field stimulator (OFS) to make it more reliable, effective and steady. In animal experiment, voltages between stimulating electrodes have been successfully recorded in different conditions such as intact, injured, exposing spinal column and suturing skin. Simulation results showed that the uniformity of electrical field of three pairs of electrodes is better than that of one pair. Experimental results indicated that a stimulating current of 10μA could generate an approximate 500μV/mm electrical field on the exposed spinal cord of rat, but a lower electrical field after suturing. In addition, voltages between stimulating electrodes would increase in deed because of transection of spinal cord.