Biomechanical Causes of Adjacent Instability after Fusion in Lumbosacral Spine

• Main Authors: Chih-Wen Chen, 陳志文
• Other Authors: C.T. Chian
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/23910464386548988353

碩士 === 長庚大學 === 機械工程研究所 === 86 === Although immobilization of spine provides satisfactory correction,it produces some complications during the follow-up clinically , such as adjacent instability . For resolving the pathophysiology of this complication , this porcine cadaveric lumbosacral spine biomechanical study is designed to find out how the lumbosacral spine adjacent unfused segment strain or torsional angle is changed by ALPS(Anterior locking plate system),RF(Reduction fixator) or ALPS+RF(Anterior locking plate system plus Reduction fixator) , and consider the possible related risk factors , such as compression , torsion , flexion , lateral bending or different length of immobilization . Three series of tests were conducted for the upper and under adjacent segment discs ,under different loading condition : (1)The flexion and lateral bending loading , (2)The torsion loading , (3) The compression loading . By the T-Test statistical method . In case (1),the experimental results showed that the upper and under adjacent segment disc strains of the test lumbosacral spines were related by the inequality ALPS+RF > RF > ALPS > NORMAL . In case (2),the experimental results showed that the upper and under adjacent segment disc torsional angles of the test lumbosacral spines also were related by the inequality ALPS+RF > RF > ALPS > NORMAL . In case (3),the experimental results showed that the upper adjacent segment disc strains of the test lumbosacral spines were related by the inequality ALPS+RF > RF=ALPS > NORMAL , and the under adjacent segment disc strains of the test lumbosacral spines were related by the equality ALPS+RF = RF = ALPS = NORMAL under the compression loading . The upper adjacent segment disc strains and torsional angles of the test lumbosacral spines were larger than the corresponding value for the under segment discs . When three segments were fixed by a fixator compared with the case that two segments were fixed ,the adjacent segment disc strains and torsional angles of the test lumbosacral spines were found to have larger values .