新型形态记忆合金颈椎夹钩治疗寰枢椎不稳的生物力学测试(英文)

Biomechanical study of neotype shape memory alloy cervical hook for atlantoaxial instability

背景:目前国内外多采用的椎弓根钉固定治疗寰枢椎不稳风险甚大,可引起钉道误置、脊髓损伤,以及椎动脉副损伤等并发症。本科充分利用记忆合金的形状记忆效应和力学特性,通过对国人寰枢椎数据测定,自行设计了一种符合寰枢椎解剖学及生物力学特征的弹性颈椎夹钩。目的:测试新型形态记忆合金颈椎夹钩治疗寰枢椎不稳的生物力学稳定性。设计、时间及地点:重复测量方差分析实验,于2008-03/04在南方医科大学临床解剖和医用生物力学实验室完成。材料:C0～C4标本均取自8具意外死亡的成年男性新鲜尸体,由南方医科大学临床解剖教研室提供。寰枢椎新型形态记忆合金颈椎夹钩,镍含量为50.8%～51.8%,余为钛,委托上海昕昌记忆合金有限公司加工制作而成。方法:上颈椎新鲜尸体标本8具依次参加4组试验,正常状态组、寰枢椎不稳组、新型形态记忆合金颈椎夹钩固定组、德国蛇牌SSE挂钩固定组。将标本固定于脊柱三维运动试验机上,施加2.0N·m的纯力偶矩。测量标本的前屈、后伸、左侧弯、右侧弯以及左、右旋转等6个运动方向的运动幅度。由激光三维扫描仪扫描上颈椎在零载荷至最大载荷状态下的位置情况,用图像处理软件分析,分别测出不同状态下的三维运动范围。主要观察指标:各组不同运动状态下的脊柱运动范围。结果:新型形态记忆合金颈椎夹钩固定组与德国蛇牌SSE挂钩固定组屈伸稳定性相当,差异无统计学意义(P=0.595);新型形态记忆合金颈椎夹钩组侧弯状态下的运动范围高于德国蛇牌SSE挂钩组(P<0.05),旋转状态下的运动范围低于德国蛇牌SSE挂钩组(P<0.05)。结论:新型形态记忆合金颈椎夹钩组具有与德国蛇牌SSE挂钩相当的术后即时稳定性。侧弯稳定性稍不及德国蛇牌SSE挂钩,旋转稳定性略优于德国蛇牌SSE挂钩。

BACKGROUND： In recent years, the pedicle screws fixation technique, which is used in fixation for atlantoaxial instability associated with trauma, severe degeneration and tumorectomy, has been developed. However, this kind of technique easily causes several complications, including malpositional screws, w, scular injuries, and even vertebral artery injury. Based on the biomechanical characteristics of memory alloy and determination of atlantoaxial data, a neotype shape memory alloy cervical hook was designed to treat atlantoaxial instability. OBJECTIVE： To investigate the biomechanical characteristics of the neotype shape memory alloy cervical hook for atlantoaxial instability. DESIGN, TIME AND SETTING： Repeated measurement analysis of variance test was performed in the Laboratory of Clinical Anatomy and Medical Biomechanics, Southern Medical University between March and April 2008. MATERIALS： Eight fresh adult craniocervical specimens （Co Ca） were provided by Department of Clinical Anatomy, Southern Medical University. Atlantoaxial neotype shape memory alloy cervical hook （50.8% 51.8% nickel and the remaining part was titanium） was fabricated by Shanghai Xinchang Memory Alloy Co.,Ltd. METHODS： The included eight Co C4 specimens were used to test three-dimension ranges of motion （ROM） by exerting 2.0 N.m moment of couple in the following sequence： intact, instability, Germany AESCULAP SSE hanger fixation and neotype shape memory alloy cervical hook fixation. Then, the positions of spine varying from no loading to the maximum loading status were scanned and analyzed using image processing software to determine the three-dimensional ROM under different statuses. MAIN OUTCOME MEASURES： Three-dimensional ROM of tested specimens. RESULTS： Neotype shape memory alloy cervical hook fixation and Germany AESCULAP SSE hanger fixation had similar flexion-extension range of motion （P = 0.595）. Lateral bending three-dimensional ROM was greater in the neotype shape memory alloy cervical hook fixation group than in the Germany AESCULAP AAE hanger fixation （P 〈 0.05）. The rotatory three-dimensional ROM was smaller in the neotype shape memory alloy cervical hook fixation group than in the Germany AESCULAP AAE hanger fixation （P 〈 0.05）. CONCLUSION： Neotype shape memory alloy cervical hook fixation had comparative post-surgery immediate stability with the Germany AESCULAP AAE hanger fixation. Neotype shape memory alloy cervical hook fixation produced a little worse biomechanical lateral bending stability and a little better biomechanical rotatory stability than Germany AESCULAP AAE hanger fixation.