Spinal canal surrogate for testing intradural implants

Abstract

We have designed, built and tested an anthropomorphic-scale surrogate spinal canal, for use in preliminary evaluations of the performance characteristics of a novel intradural spinal cord stimulator. The surrogate employs a silicone mock spinal cord with semi-major and semi-minor diameters of 10 and 6 mm, respectively, commensurate with those of actual thoracic-level spinal cord. The axial restoring force provided by the 300 µm thick silicone denticulate ligament constructs on the mock cord is ~ 0.32 N mm⁻¹ over a 1.5 mm range of displacement, which is within a factor of 2 of that measured by others in human cadaver specimens. Examples of testing protocols of prototype intradural stimulators that employ this device are discussed.

Keywords::

• Spinal cord
• spinal canal
• spinal cord stimulator
• neuromodulation
• intradural implants

Acknowledgements

The parts for the surrogate spinal canal device were skillfully fabricated by M. Wardenburg in the University of Iowa’s Medical Instrument Shop. The work at the University of Virginia was supported in part by the Kopf Family Foundation, Inc.

Declaration of interest: Howard and Gillies may receive patent royalties from any commercial licensing of the Iowa-Patch^™ intellectual properties that might be negotiated by their respective institutions.