On electrode configuration for low-back peripheral nerve field stimulation

Abstract

Peripheral nerve field stimulation (PNFS) has been proposed as treatment for chronic low-back pain. With this technique an electrode is implanted in the subcutaneous tissue in the painful area. No specific nerve is isolated and the neural target appears to be the tactile cutaneous nerve fiber branches. In order to understand the neural mechanisms behind PNFS a mathematical model has been proposed. The aim of the present study is to investigate the activation of tactile Aβ-fibers and nociceptive Aδ-fibers. A finite element model of the cutaneous and subcutaneous tissue was used to estimate the electrical field generated by two subcutaneously implanted electrodes. The estimated electrical field was used to estimate the activation threshold and location by a stochastically branching nerve fiber model. The model showed that the area of Aβ-fiber activation was always larger than the area of Aδ-fiber activation. While most electrode configurations provided similar areas of nerve fiber activation, the guarded cathode configuration may be slightly better than the other configurations.