颈椎前路微型记忆加压合金板的体外生物力学研究

In vitro biomechanical study of anterior cervical micromemory compression alloy plate

目的:采用体外生物力学研究方法评估颈椎前路椎间盘切除融合内固定手术的微型记忆加压合金板(GYZ记忆合金板)置入后的即刻稳定性。方法:6具新鲜颈椎尸体标本,男性,年龄55.2±7.1岁,身高175.4±3.8cm,体重72.3±6.0kg。通过薄层CT及骨密度检查,排除畸形、骨折、骨质疏松等疾病。所有标本剔除脊柱周围血管、肌肉等软组织,保留韧带、关节囊后,先后制作为生理组、损伤组、新型合金板组、传统钛板组4组:生理组为空白对照组;损伤组标本仅将C3/4椎间盘破坏;新型合金板组将C3/4椎间盘切除后置入椎间融合器,前路辅助GYZ记忆合金板融合固定;传统钛板组前路辅助传统钛板固定。每组标本均在前屈、背伸、左右侧弯、左右扭转方向上给予1.5N·m的载荷。记录第3次试验的结果并对四组标本C3/4椎间隙在前屈、背伸、左右侧弯及左右扭转方向上的活动度进行对比分析。结果:术后影像学检查显示置入物位置良好。生理组C3/4在前屈、背伸、左侧弯、右侧弯、左旋转、右旋转方向上的活动度分别为4.8°±0.5°、2.5°±0.1°、2.4°±0.3°、2.6°±0.3°、2.0°±0.2°与3.9°±0.1°;损伤组分别为6.0°±0.7°、3.4°±0.3°、3.4°±0.5°、3.8°±0.6°、2.4°±0.9°与5.7°±1.3°,较生理组明显增大(P<0.05)。新型合金板组C3/4椎间隙在上述六个方向上的活动度分别为0.6°±0.1°、0.4°±0.1°、0.5°±0.1°、0.7°±0.1°、0.6°±0.1°及1.0°±0.1°,传统钛板组分别为0.6°±0.1°、0.5°±0.1°、0.5°±0.1°、0.7°±0.1°、0.5°±0.1°与1.0°±0.1°,两组在各方向上的活动度无明显差异(P>0.05)。结论:微型记忆合金板可以获得与传统钛板相似的固定强度和重建手术部位的即刻稳定性。

Objectives:To evaluate the immediate stability of a new miniature memory compression alloy plate(GYZ memory alloy plate)for anterior cervical discectomy and fusion through biomechanical test in fresh cadaver specimens.Methods:Thin layer CT scan and bone density examination were on the cervical spine of 6 fresh cadaveric specimens(male,average age:55.2±7.1 years old,average height:175.4±3.8cm,average weight:72.3±6.0kg)to exclude fractures,deformities and osteoporosis.All specimens were removed from peripheral blood vessels,muscles and other soft tissues,while ligaments and joint capsules were retained.Then,the specimens were divided into intact group,injury group,new alloy plate group and traditional titanium plate group.In the intact group no treatment was given.In the injury group,only the C3/4 intervertebral disc was damaged.In the new prosthesis group,C3/4 intervertebral fusion and fixation with GYZ memory alloy plate was given.In the traditional titanium plate group,C3/4 intervertebral fusion and fixation with traditional titanium platewas given.Each group was loaded under 1.5N·m in the direction of flexion,extension,left and right lateral bending and left and right torsion.The results of the third experiment were recorded and the range of motion(ROM)of C3/4 intervertebral disc in flexion,extension,left and right lateral bending and left and right torsion direction of the four groups were collected and analyzed.Results:Postoperative imaging showed that the position of the prostheses was normal.In the intact group,the ROMs of C3/4 disc in flexion,extension,left lateral bending,right lateral bending,left rotation and right rotation were 4.8°±0.5°,2.5°±0.1°,2.4°±0.3°,2.6°±0.3°,2.0°±0.2°and 3.9°±0.1°,respectively.The ROMs of C3/4 disc in the injury group were respectively 6.0°±0.7°,3.4°±0.3°,3.4°±0.5°,3.8°±0.6°,2.4°±0.9°and 5.7°±1.3°.Compared with the intact group,the C3/4 ROMs in the injury group in flexion,extension,lateral bending and rotation direction increased significantly(P<0.05).The C3/4 ROMs in the new alloy plate group in the above six directions were 0.6°±0.1°,0.4°±0.1°,0.5°±0.1°,0.7°±0.1°,0.6°±0.1°and 1.0°±0.1°,respectively,while those in the traditional titanium plate group were 0.6°±0.1°,0.5°±0.1°,0.5°±0.1°,0.7°±0.1°,0.5°±0.1°and 1.0°±0.1°.The ROMs of the new alloy plate group and the traditional titanium plate group decreased significantly in the above directions(P<0.05).There was no significant difference in ROMs between the new alloy plate group and the traditional titanium plate group in the above directions(P>0.05).Conclusions:The miniature memory alloy plate can obtain the fixation strength and the immediate stability of the operation site similar to the traditional titanium plate.