Feasibility of Minimally Invasive Fiber Based Evaluation of Chondrodystrophoid Canine Intervertebral Disc by Reflectance Spectroscopy

Abstract

The objective of this study is to investigate the feasibility of using a fiber-needle spectroscopy sensor to analyze the changes of tissue compositions involved in the chondrodystrophoid condition of the canine intervertebral disc. Reflectance spectrum of single fiber reflectance spectroscopy is expected to provide information of scattering and absorption compositions of tissue in proximity to the fiber-tip. The reflectance spectrum model of single fiber reflectance spectroscopy has been validated by Intralipid and polystyrene phantoms studies. Preliminary measurements on cadaveric canine intervertebral discs indicated significant reduction of scattering constituents and possible diminishment of water content after percutaneous laser disc ablation (PLDA). Cadaveric measurements revealed that the calcified discs have higher scattering amplitude and lower scattering power than normal discs. And when using scattering amplitude to differentiate the normal and calcified discs, 99.28% area under curve has been achieved according to Receiving Operating Characteristic (ROC) curve. Although the water content could not be quantitatively calculated, the absorption from water is observed in the reflectance spectrum. Intralipid phantom study and cadaveric measurements reveal that fiber-needle based sensing configuration may be feasible for integrating the evaluation of calcification and water content into the work-flow of Ho:YAG laser disc ablation for pre-operative in-line detection and post-operative evaluation of therapeutic interventions regarding the chondrodystrophic disc.