腰椎L_(4/5)棘突间椎间融合器的生物力学特性及生物相容性

Biomechanical properties and biocompatibility of the L_(4/5) lumbar spine fusion cage

背景:腰椎管狭窄引起腰椎两侧神经根痛等不适症状甚至致残,严重影响人们的生活质量,针对这种疾病临床上主要采用椎间融合治疗。有研究表明棘突融合器易出现骨裂及植入器脱落等现象,所以实验从腰椎L4/5棘突研究椎间融合器的生物力学特性和生物相容性。目的:分析研究腰椎L4/5棘突间植入椎间融合器的稳定性,以及对相邻节段的生物力学特性和生物相容性。方法:选择10组新鲜的成人冰冻脊柱标本,将10个标本分为2组,分别为正常标本组和模拟腰椎棘突间植入物组,每组5例。对标本进行编号并放置固定在特殊的夹具中,使用由郑州凯斯特医疗器械有限公司生产的腰椎融合器,选择棘突间弹性内植入,由Ti6AL-4V ELI钛合金构成的cage固定器固定。结果与结论:人工椎体不同植入位置在中心压缩、前屈、后伸、侧屈4种状态下的应变变化均小于正常组标本(P<0.05)。两组标本在最大载荷500 N下椎体的位移数据中,与正常标本组比较,模拟腰椎棘突间植入物组线性位移和角位移在前屈、后伸、左侧屈、左旋转时均减小(P<0.05)。结果表明,腰椎棘突间融合器能够保留伤椎的大部分活动度,维持节段稳定性,降低椎间盘应力。

BACKGROUND： Lumbar spinal stenosis can result in lumbar nerve root pain and other symptoms or even disability, which seriously impacts people＇s quality of life. Interbody fusion is the main clinical treatment. Studies have shown that an interspinous fusion cage is prone to have hairline fractures and loss of implant; therefore, biomechanical properties and biocompatibility of the interbody fusion cage at L4/5 need to be studied. OBJECTIVE： To analyze the stability of the interspinous fusion cage at L4/5, and to explore the biomechanical properties and biocompatibility of adjacent segments. METHODS： Ten adult fresh frozen spine specimens were selected and divided into normal group and model group, with five specimens in each group. The specimens were numbered and placed in a special fixture. The interspinous fusion cage, made in Zhengzhou Cast Medical Instrument Co., Ltd., China, was implanted in vivo and fixed using a cage fixator made of Ti6AL-4V ELI. RESULTS AND CONCLUSION： Artificial vertebral bodies had less strain changes than the normal vertebrae in different implantation positions in terms of central compression, anteflexion, rear protraction, lateroflexion（P〈0.05）. During vertebral displacement under the maximum load of 500 N, the linear displacement and angular displacement in anteflexion, rear protraction, left lateral flexion, levorotation were decreased significantly in the model group than the normal group（P〈0.05）. These findings indicate that the interspinous fusion cage can maximally preserve the range of motion of the injured vertebral body, maintain the stability of the segment, and reduce the stress of the intervertebral disc.