不同前路中空加压螺纹钉内固定治疗Ⅱ型齿突骨折的生物力学评价

背景：目前前路中空加压螺钉固定被认为是治疗齿突骨折的较理想方法。目的：比较不同前路内固定螺钉的生物力学特性。设计、时间及地点：随机分组设计,对比观察,于2006-03/09在南方医科大学生物力学实验室完成。材料：双头螺纹中空加压螺钉和单头螺纹中空加压螺钉均为钛合金材料,由苏州双羊医疗器械有限公司生产制作。方法：20具防腐尸体头颈复合体（C0～C3）标本,甲醛浸泡不超过3个月,剔除其肌肉、韧带,取其枢椎标本,制成齿突Ⅱ型骨折模型。实验分为2组,双头螺纹螺钉组和单头螺纹螺钉组分别用双头螺纹和单头螺纹中空加压螺钉固定骨折,每组10例。主要观察指标：测试两种螺钉的剪切刚度和最大拔出力。结果：双头螺纹螺钉组的剪切刚度明显高于单头螺纹螺钉组（P〈0.01）。而最大拔出力差异无显著性意义（P〉0.05）。结论：双头螺纹中空加压螺钉治疗齿突骨折具有更强的生物力学稳定性;对于骨质梳松者和手术操作引起钉道扩大的患者,应首选双头螺纹中空加压螺钉。

Biomechanical evaluation of internal fixation of different anterior canulated screws for the treatment of type odontoid fracture

BACKGROUND:Antedor canulated screw has been considered an ideal method to treat odontoid fracture.OBJECTIVE:To compare the biomechanical properties of different anterior screws.DESIGN,TIME AND SETTING:A randomized contrast study was performed at the Biomechanics Laboratory of Southern Medical University from March to September 2006.MATERIALS:Double-thread canulated screws and single-thread canulated screws were made of titanium alloy and provided by Shuangyang Medical Apparatus Co.,Ltd.,Suzhou.METHODS:A total of head-neck complexes (C0-C3) which were collected from 20 corpses were maintained in formaldehyde for less than 3 months;thereafter,the muscles and ligaments were removed to obtain the axis specimens so as to make type Ⅱ odontoid fracture models.The fracture samples were individually treated with double-thread and single-thread canulated screws,with 10 samples for each group.MAIN OUTCOME MEASURES:The shear stiffness and the maximum resistance of the two kinds of screw were tested in this study.RESULTS:The shear stiffness of the double-thread screw group was significantly higher than the single-thread screw group (P＜0.01 );however,there was no significant different in the maximum resistance between the two groups (P＞0.05).CONCLUSION:Double-thread canulated screws have a strong biomechanical stability for treating odontoid fracture;therefore,the first choice of the internal fixation should be double-thread canuiated screws for patients with osteoporosis or those who are susceptible to expanded screw pathway during surgical procedures.