Development and Comparison of iniature Intradiscal Pressure Transducers ade of Optic Fibers and Strain Gages
Date Issued
2009
Date
2009
Author(s)
Huang, Wei-Cheng
Abstract
Objective: To develop low-cost, easy-to-made, high-pressure miniature intradiscal pressure transducers using optic fibers and strain gages.ummary of Background Data: Intradiscal pressure (IDP) is an import mechanical index for the evaluation of spinal function. The method to measure the IDP is to introduce a pressure sensor into the nucleus pulposus. The damage due to the insertion of sensor decreased with smaller dimension of the sensor. The strain gage type transducer is frequently used to measure, but its dimension is relatively large, and may induce the interference to the measurement. The size of fiber optic type transducer can be very small, but the stability and repeatability of this type of transducer is still not reliable.aterial and Method: The intensity-based fiber optic transducer system is composed of pressure transducer, power meter and coupler. The fiber optic transducer is made of single mode optic fiber, 25 G needle, and ethylene-vinyl acetate copolymer. The stain gage type transducer is composed of pressure transducer, Wheatstone bridge circuit and signal amplify. The strain gage transducer is made of strain gage, 20 G needle, and ethylene-vinyl acetate copolymer. The transducers are calibrated by a home-made calibration system, which is composed of a hydraulic chamber connected with a tested transducer, a standard transducer, and a driving pump. The pressure limit of this calibration system is 1.6 MPa. After calibration, a porcine disc specimen is used to test the maneuver and feasibility of these transducers. onclusion: This study successfully minimizes the dimension of strain gage type transducer to 20 G needle with high accuracy, precision and sensitivity. This study also showed a new type of fiber optic transducer and integrated it into a 25G needle. Nevertheless, the hysteresis and repeatability of this type of transducer made it less practical for the in vivo or in vitro experiments.
Subjects
Nucleus pulpous
Minimally invasive
Fiber optic transducer
Strain gage transducer
Intradiscal pressure
Type
thesis
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