人工腰椎间盘置换后下位关节突关节内压力的变化

Stress changes in inferior facet joint after artificial lumbar disc replacement

目的:腰椎间盘和关节突关节共同维持腰椎的稳定,任何一个部分的退行性变都将引起另两部分的退变。观察SB Charite人工腰椎间盘假体置换对相邻下位关节突关节内压力的影响,以提供人工椎间盘临床应用的生物力学参数。方法:实验于2003-03在国防科技大学航天与材料工程学院力学实验室完成。①实验材料:10具新鲜成人尸体腰椎标本,包括L2～5椎体及其椎间盘,死者均为急性脑死亡的健康青壮年。肉眼及X射线观察以排除标本无畸形、退行性变及结构性破坏。剔除椎旁肌肉及其筋膜组织,保留所有的韧带、椎间盘及关节囊并维持其完整性。②实验方法及评估:将Ω状微型电阻式压力传感器置入L4/5关节突关节,分别测量L3/4椎间盘完整和人工椎间盘置换两种状态下轴向(400～2000N)、后伸、对侧弯和同侧弯(2～10N·m)载荷4种工况时L4/5关节突关节内的压力。结果:纳入成人尸体腰椎标本共10具,均进入结果分析,实验过程中标本无破坏和脱落。轴向、后伸、同侧弯及对侧弯加载条件下,人工椎间盘置换组与椎间盘完整组比较,下位关节突关节内压力差异均无显著性(P>0.05)。结论:①人工腰椎间盘置换后相邻下位关节突关节内压力与正常时无明显改变。②人工椎间盘置换在重建腰椎生物力学性能的同时不会引起相邻下位关节突关节内压力的改变。

AIM：Intervertebral disc and facet joint are congenerous to maintain the lumbar stability, and any degeneration may lead to the cataplasia of other two parts. Our goal is to study the changes of stress in the neighboring inferior facet joint after SB Charite artificial lumbar disc replacement （ADR）, and provide advanced theoretical evidences for ADR in clinical treatment. METHODS： The experiment was carried out in the Mechanics Laboratory, College of Aerospace and Material Engineering, the National University of Defense Technology in March 2003.①Ten samples of fresh cadaveric lumbar spine L2-5 segment and intervertebral disc were selected from healthy young adults who died of acute brain death. Those of abnormalities, degeneration and structural destruction were excluded through macroscopic and X-ray observations. Paravertebral muscles and fascia tissues were eliminated to integrate all the ligament, intervertebral disc and articular capsule.②All specimens were divided into L3/4 disc intact group and ADR group, applying different grades of loading-force in axial direction （400-2 000 N）, extension, lateral flexion and contralateral flexion （2-10 N·m）. A special Ω type miniature sensor was put in the L4/5 facet joint and the stress in it was measured. RESULTS： Ten adult cadaveric lumbar specimens all entered the analysis, without destruction and dislocation. When applied with graded-loading-force in axial, extension, lateral flexion and contralateral flexion conditions, the average stress of inferior facet joint in ADR group was not significantly different, compared with the disc intact group （P 〉 0.05）. CONCLUSION： ①There are not significantly changes of the stress in the inferior facet joint after ADR.②ADR will not add negative influence to the inferior facet joint when it rebuilds the biomechanical characteristics of lumbar spine.