Biophysical attributes of an <i>in vitro</i> spinal cord surrogate for use in developing an intradural neuromodulation system

Abstract

We have developed a spinal cord surrogate for use in testing a pial-surface spinal cord stimulator. Our surrogate is of a commercially available silicone mix, has an oval cross-sectional area that matches that of actual human spinal cord at the lower thoracic level, and has measured values of durometer A = (10.96 ± 1.68), durometer O = (14.76 ± 1.48), and durometer OO = (50.24 ± 2.65). These correspond to model-inferred elastic moduli of 0.41 to 0.44 MPa, which match well with the existing low-strain rate measurements of ex vivo human spinal cord. Upcoming applications for this surrogate in developmental studies of the new stimulator system are discussed.