摘要
目的设计一种可经皮微创置入的新型动态腰椎内固定器,评价其生物力学特性。方法该固定器活动度分为2°(Ⅰ型)和10°(Ⅱ型)两种。利用7具成年新鲜的猪腰椎骨标本进行三维运动和刚度试验。测试三维运动时,每个标本按完整状态(A组)、失稳状态(B组)、坚强固定状态(C组)、动态固定Ⅰ型状态(D组)、动态固定Ⅱ型状态(E组)顺序测试。结果 (1)三维运动测试结果:1失稳标本经新型动态内固定器固定后(D组、E组),前屈、后伸、左右侧屈和左右轴向旋转分别比A组和B组均明显减少(P<0.05),但与C组比较,活动度明显增大(P<0.05)。2D组、E组之间比较,E组比D组具有更大的前屈活动度(P<0.05),后伸、左/右侧弯、左/右旋则无明显差异(P>0.05)。(2)刚度测定结果:D组和E组的刚度均强于A组,但均弱于C组,E组比D组弱。结论该动态腰椎内固定器Ⅰ型和Ⅱ型均能保证脊柱稳定性,且有一定的活动范围;螺钉活动度为10°的更接近脊柱生理活动范围;螺钉的活动度对内固定器的强度有一定影响。
Objective To design a posterior dynamic stabilization of lumbar vertebrae by percutaneous placement and evaluate its biomechanical propertiesby experiments. Methods Medical titanium alloy was usedto design a set of pedicle screw rod fixation system. The combining site of body with U screw tail was similar to joint structure. There were 2~ range of motion （type I ） and 10~ （type II ） range of screw, and hollow screw, and cylindrical connecting rods. Seven adult fresh pig lumbar spine specimens were used for mechanical testing： six lumbar vertebrae were tested three dimensional motion, and all 7 specimens underwent compression test. When tested three dimensional motion, five patterns of state of every specimen were tested in sequence, respectively. The five patterns of state was as followings： complete state （group A）, instability state （group B）, stiff fixation state （group C）, dynamic fixation state I type （group D）, dynamic fixation state Ⅱ type （group E）. Motions of flexion/extension, lateral bending and axial rotation were produced by six pure moments with maximum of 10.0 N· m and measured with stereo photogrammetry. Results （1） The results of the three dimensional motion test： ①After fixation with type I or type Ⅱ, motions of flexion was （1.577 ± 0.177）~ and （1.988 ± 0.096）~, respectively. Extension was （1.900 ±0.119）~ and （2.135 ± 0.143）~, respectively. Left lateral bending was （2.549±0.280）°and （2.712±0.215）°, respectively. Right lateral bending, respectively was （2.454±0.201）° and （2.590±0.203）°. Left axial rotation was （1.458±0.294）° and （1.694±0.250）°, respectively. Right axial rotation was （1.666±0.221）° and （1.842±0.163）°, respectively, which was significantly decreased when compared with that the complete state and the state of instability （P〈0.05）and were significantly enhanced when compared with that of the stiff fixation state （P〈0.05）.②Two kinds of dynamic state of fixed type （ I and Ⅱ ） between each other, Ⅱ more than I proneness activity （P〈0.05）, but there was no obvious difference of extension, lateral bending and axial rotation （P〉0.05）. （2）Stiffness measurement results： the maximum load of the two dynamic type I fixed specimens was 3571 N and 2839 N, respectively; The maximum load of the two specimens with dynamic type Ⅱ fixed was1961 N and 2365 N, respectively, dynamic fixed I and Ⅱ, and strong fixation stiffness were greater than complete state, and type Ⅱ less rigid than type I state. Conclusion The posterior dynamic stabilization of lumbar type I and typeⅡ can ensure stability of the spine, and keep a range of motion, 10° of screw motion closer to the spinal physiological activities. The range of motion of screw has effects on the strength of the internal fixator.
出处
《中国临床解剖学杂志》
CSCD
北大核心
2014年第4期458-461,共4页
Chinese Journal of Clinical Anatomy
基金
广西壮族自治区科技攻关项目(桂科攻1140003B-63)
关键词
经皮
微创
后路动态固定器
腰椎
生物力学
Percutaneous
Minimal invasive
Posteriordynamic stabilization
Lumbar
Biomechanical
