Miniature Fiber Optic Pressure Sensors for Intervertebral Disc Pressure Measurements in Rodents

Abstract

Mechanical stress due to interstitial fluid pressures can play a major role in the development of disc degeneration, a common cause of lower back pain. Pressures generated in the intervertebral disc have previously been measured in humans and animals. However, due to their small size, thus far it has been difficult to experimentally measure pressures in rodents. With the prevalent use of rodent disc models in mechanobiology, it is important to characterize the intradiscal pressures under externally applied stresses. In this thesis research, two different optical systems with novel miniature fiber optic pressure sensors have been developed. These systems are an intensity based solid-tip sensor system and a low coherence Fabry-Perot sensor system. Pressure sensors, which have diameters of only 363 µm, were designed to measure pressures in rat discs without disrupting the structure and altering the intradiscal pressures. For the first time, in vitro intradiscal pressure measurements of rodents have been successfully demonstrated by using these sensors.