A Real Time Monitoring System for Spinal Fusion Surgery

University Of Louisville Research Foundation Inc, Louisville KY

Investigators

Abstract

0097521 Hnat The objective of this research is the development of an implantable strain sensor and appropriate measurement system to monitor real time spinal fusion rod strain. As the spine fuses, the load is transferred from the rod to the spine. Therefore, the monitored strain on the rod surface should decrease over time. The load transfer for a normal spinal fusion should be gradual and steady, and any deviation of discontinuity would indicate either non-fusion or possible failure of the rod or pedicle screw. A complete measurement system including microstrain sensors, signal conditioning, battery-free telemetry, sensor housing and an external receiver will developed and then tested using whole cadavers. Micromechanical systems (MEMS) technology will be implemented to produce a miniature strain sensor. Two integrated circuits (ICs), a MOSFET switch and a LC antenna tank circuit placed on a multi-chip module (MCM) board will provide strain sensor signal conditioning and telemetry transmission. The sensor and electronics housing will be developed using advanced mechanical design methods combined with rapid prototyping using selective laser sintering. Measurement system verification will be conducted using whole cadavers and surgical implantation of the fusion rod strain sensors. The lumbo-sacral spine segment will be removed from the cadavers and tested using a MTS Bionix test system to determine system sensitivity.