Modeling and Optimization of Neural Activation during Spinal Cord Stimulation

Spinal Cord Stimulation (SCS) is a neurostimulation technique used to alleviate several kinds of chronic pain. Computer modeling of SCS is a powerful tool in predicting the effects of an electrical stimulus on nerve fiber activation. The UT-SCS, developed at the University of Twente, Enschede, The Netherlands, has provided useful insights on the mechanisms of SCS. Nevertheless, this software presents several limitations. This work aimed at building a first approach to a novel SCS model in an attempt to overcome the UT-SCS software limitations. A state-of-the-art Finite Element software, COMSOL Multiphysics®, was used in combination with MATLAB. Several fiber activation parameters were determined and compared with those yielded by the UT-SCS model. The simulations were performed for two different three-lead configurations and the current was gradually steered across the contacts. In general, the results given by the two SCS models were in agreement. The differences were hypothesized to be due to geometrical differences between the two models. Moreover, the potential field distributions were more robust in the COMSOL model than in the UT-SCS. The performance of the two contact configurations in the new SCS model was then compared. The configuration consisting of two anodes on each side of a cathode gave overall better results at the cost of a lower current amplitude.