枢椎影像学测量与镁合金中空拉力螺钉设计与制作

Axis of radiographic measurements with magnesium alloy hollow lag screw design and production

目的研究正常人齿状突及Ⅱ型齿状突骨折的基本影像数据,指导设计Ⅱ型齿状突骨折的内固定可降解AZ31B镁合金中空螺钉设计与制作。探讨采用镁合金中空拉力螺钉治疗Ⅱ型齿状骨折的可行性。方法来自广州军区广州总医院的正常成人齿状突螺旋CT影像资料150份,Ⅱ型齿状突骨折影像资料43份,在计算机上采用螺旋CT的影像标尺直接测量枢椎的总高度、齿状突长度、骨折线距齿状突尖的距离、齿突后倾角及枢椎可供中空螺钉固定长度。根据影像学数据设计出理想的镁合金中空螺钉并在6具尸体标本模拟ⅡB型齿状突骨折镁合金中空螺钉内固定,术后目测骨折端即时稳定性。结果枢椎高度为(35.11±4.15)mm,齿状突长度(14.99±1.26)mm,齿状突基底的冠状径为(8.94±1.26)mm,矢状径为(10.20±1.02)mm,骨折线距齿状突尖的距离为(10.49±1.75)mm,进针后倾角(17.56±5.29)°。结论国人Ⅱ型齿状突骨折内固定的螺钉长38 mm,直径3.5 mm,远端螺纹长约1 cm较合适。设计出可降解AZ31B镁合金中空螺钉外表美观,与临床使用钛合金中空螺钉外形基本相符,操作便利,目测骨折端即时稳定性好,为下一步行生物力学检测提供依据。

Objective To investigate normal people＇s odontoid process and type II odontoid fracture basic image data, to guide the design of type I1 odontoid fracture fixation with biodegradable magnesium alloy AZ31B hollow screw design and production and the feasibility of magnesium alloy hollow lag screws for treatment of fractures of type II odontoid. Methods One hundred and fifty cases of normal adult odontoid screw CT image data and 43 cases of type II odontoid fracture image data from Guangzhou General Hospital of Guangzhou Military Command were included. On computer the spiral CT imaging scale was used for direct measurement of axis odontoid process, total height, length of fractures of odontoid tip distance from the line, after the angle and axis odontoid process for hollow screw fixation length. According to the imaging data, the ideal magnesium alloy hollow screws were designed and in cadaver specimens simulation was made for type IIB odontoid fracture of magnesium alloy hollow screw fixation, postoperative visual fracture end instant stability. Results Axis height was （35.11±4.15）mm, odontoid length （14.99±1.26）mm, odontoid basal coronary diameter was （8.94±1.26）mm, sagittal diameter was （10.20±1.02）mm, fracture line from odontoid tip distance of （10.49±1.75）mm, the needle after the dip （17.56±5.29）°. Conclusion The type II odontoid fracture fixation screw has length 38 mm, diameter 3.5 mm, about 1 cm long appropriate distal screw. Design of biodegradable magnesium alloy AZ31B hollow screws combined with beautiful appearance conforms to clinical titanium alloy hollow screw, with convenient operation, good visual fracture end instant stability. It provides the basis for the biomechanical tests.