经皮前路螺钉内固定技术治疗儿童齿状突骨折的可行性分析

Analysis for children odontoid process with anterior percutaneous screw fixation

目的研究不同年龄儿童齿状突的各种参数变化，为经皮齿状突螺钉内固定提供参数依据。方法收集我院2005年9月到2012年12月因外伤行颈部CT检查的436例患儿影像学资料，利用CT二维重建技术，选入176例，按年龄分为三组，A组：≤6岁，共40例，其中男18例，女22例；B组：〉6岁，≤12岁，共75例，其中男40例，女35例；C组：〉12岁，≤18岁，共61例，其中男34例，女27例。测量儿童齿状突基底部冠状外径（D），齿状突基底部矢状外径（A），齿状突长度（0B），枢椎椎体高度（AB），以及齿状突轴心线与C3椎体垂直角的夹角（a）。结果小于6岁儿童齿状突基底部冠状外径（4．21±1．62）mm，外径不足以容纳单枚螺钉，或者旋人螺钉后容易造成齿状突劈裂；6～12岁儿童，测量结果为（5．50±2．80）mm，结果变异较大，12～18岁儿童，其测量结果（8．64±1．68）mm接近于成人；因此对于6～18岁的儿童，应注意个体化；儿童齿状突的齿状突长度，枢椎椎体高度以及齿状突轴心线与C，椎体垂直角的夹角测量结果小于正常成人的长度及角度。结论对于小于6岁的儿童，齿状突骨折不推荐采用经皮齿状突螺钉内固定技术；对于6～18岁的儿童，该技术有一定的可行性，但要注意个体化原则，术前要结合齿状突不同年龄不同参数变化，选择相应的螺钉直径，长度及角度。

Objective To provide the basis parameters for anterior percutaneous screw fixation through computed tomography （CT） data of odontoid process in different age groups. Methods A total of 176 cases were divided into three groups of A （46 years of age, n = 40, 18 males ＆ 22 females）; B （6 to 12 year old, n=75, 40 males ＆35 females）; C （12 to 18 years old, n=61, 34 males ＆ 27 females）. Using two-dimensional CT reconstruction technology, the relevant odontoid parameters were measured, including coronal and sagittal external diameters of odontoid process base, length of odontoid process, total axial height and angle between axial lines of odontoid process with vertical line of anterosuperior border of C4 vertebral body. Results The coronal external diameter of odontoid process base under 6 years old was （4. 21 ± 1.62） mm and it was insufficient to accommodate a single screw. Or it resulted easily in a burst of odontoid process upon screwing in. And for 6-12 year old child, （5.50 ± 2. 80） mm with great variations. And for 12-18 years old, （8. 64 ± 1.68） mm with results closer to adults. So for 6-18 years old, individualization was stressed. Regarding total axial height and angle between axial lines of odontoid process with vertical line of anterosuperior border of （23 vertebral body, the results were less than those of adults. Conclusions For children aged under 6 yearspercutaneous odontoid screw fixation technique is not recommended; For children 6 to 18 years old, this technology has some feasibility, but we should pay more attention to the principle of preoperative individualization. Appropriate screw diameter, length and angle are selected based upon the actual results.