FEA Modeling of Spinal Stimulator

Parametric electrostatic FEA model of articulating spinal cord stimulator leads with scripting interface

Mosaic developed finite element electrical models for Spinal Modulation to help them better understand the electrical characteristics of a novel articulating spinal cord stimulation (SCS) lead design.

Spinal cord stimulation is a technique in which electrical stimulation electrodes are surgically implanted adjacent to the spinal cord and/or dorsal root ganglia in order to provide therapeutic pain relief.

One challenge with this approach is the limited specificity in stimulating regions of the dorsal root ganglion nerve bundle. Spinal Modulation developed an articulating multi- electrode lead which can be threaded through the intervertebral foramen during surgery, providing more targeted therapy. We worked with Spinal Modulation to develop a finite-element analysis (FEA) model using COMSOL Multiphysics. This included an electrical tissue compartment model of the spinal cord and vertebral anatomy as well as a parametric model of the stimulation lead. The model calcualted current density and electric potential in three dimensions, as well as the nerve activating function, which estimated nerve fiber recruitment as a function of extracellular field potentials. We developed a simple scripting interface to parameterize geometric and stimulation parameters. This script generated the 3D model, ran the electrostatic simulations in COMSOL, and generated output data in an annotated powerpoint deck for review by the team.