The Measurement of Intradiscal Pressure

• Main Authors: Chia-Chung Chang, 張家駿
• Other Authors: 王兆麟
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/35562108332815350072

碩士 === 國立臺灣大學 === 醫學工程學研究所 === 93 === Summery of Background Data. In recent years, it is a mainstream to replace injured intervertebral discs with artificial ones to maintain the function of disc, such as remain distance between two vertebral bodies, transmit compressive force and keep stability of spine. Before achieving these goals, it is important to understand biomechanics of disc. Objectives. The objectives of current study are to measure intradiscal pressure with thoracic one-motion segments under different loading condition. Prior to the study, a needle pressure sensor was developed. Two orientation of sensor insertion were employed to investigate how the invasion of instrument influenced the measurements of disc pressure. Methods. 18 porcine thoracic one-motion segments were subjected to 1.2J of impact loading acting on different location of top of specimens, simulating forwards flexion, neutral erect position and backward extension. Intradiscal pressures were measured in each loading condition by inserting the needle pressure sensor into intervertebral disc with anterior and lateral approach, respectively. Results. In motion segments with pressure sensor approached anteriorly, the average intradiscal pressures were 1.5 MPa (loading on vertebra body) and 0.6 MPa (loading on posterior process), respectively. With pressure sensor approached laterally, intradiscal pressures in average were 1.1 MPa (loading on vertebra body) and 1.4 MPa (loading on posterior process), respectively. Results showed that orientation of sensor insertion influenced outcome of pressure measurement significantly. Conclusions. Three possible reasons might explain the results of current study. First, insertion of needle pressure sensor could make damage to annular fiber, and then decrease the ability of disc to sustain bending moment. Second, sensor invasion might change location of center of spine rotation. Third, sensor insertion causes the fluid of nucleus to flow out and to expand volume of nucleus.