上胸椎前路金属植入物内固定的相关解剖学径路

Anterior screw metal implant fixation of the upper thoracic spine:An anatomic study

背景:国内外少见与上胸椎前路内固定相关的解剖学研究报道。目的:通过测量上胸椎(T1～4)骨骼标本相关解剖学数据,分析上胸椎前路内固定的进钉深度、选择螺钉长度以及钢板、内固定棒的预弯角度。方法:取完整的成人干燥脊柱骨标本,要求有完整的颈胸段,依照《人体骨骼测量方法》的标准和方法用游标卡尺测量T1～4各个椎体的相关解剖学数据,包括椎体前高、椎体后高、椎体上矢径、椎体下矢径、椎体上横径、椎体下横径、椎体最小横径。取正常成人颈胸段MRI正中矢状位片,分别以T1,T4为端椎用电子量角器测量得Cobb角度数。结果与结论:上胸椎椎体后高均大于椎体前高,从而维持了颈胸段脊柱的生理性后凸。由于正前方安置固定螺钉时有内倾和头尾倾斜的角度,因此实际钉长及进钉深度要大于相应椎体的矢状径。椎体最小横径比上下横径都小,在进行上胸椎侧前路内固定时应参照最小横径的测量结果选择合适的钉长及进钉深度。正常成人上胸椎MRI正中矢状位片测得的Cobb角为(7.20±2.04)°,内固定过程中在内固定钢板或内固定棒置入之前需根据正常Cobb角进行预弯以便达到紧密贴合。

BACKGROUND：There are few reports about anatomic study addressing the anterior screw fixation of the upper thoracic spine.OBJECTIVE：To measure the anatomy data of T1-4 segments in order to analyze the depth to insert the screw,screw length and the bending angle of the steel plate or rob for upper thoracic anterior screw fixation.METHODS：Fifty dry specimens of T1-4 segments were used to measure the relative anatomic data,including the anterior and posterior height,upper and lower radius vector,upper and lower transverse diameter,and the smallest transverse diameter.Fifty center anteroposterior axial MRI photographs of the upper thoracic spine of normal native adults were used to measure the Cobb＇s angle by electronic conimeter,and T1 and T4 was considered as the vertebral end.RESULTS AND CONCLUSION：All of the posterior height of the upper thoracic vertebral body was higher than the anterior height of the vertebral body.So the physiological concave bending of the upper thoracic spine was maintained.Because of the inclination,the depth and the length of the screw should be bigger than the upper and lower antero-posterior diameter of the right vertebral body.We should refer to the smallest transverse diameter of vertebral body to select the suitable length and depth screw in latero-anterior fixation of the upper thoracic spine.The Cobb＇s angle on the anteroposterior axial MRI photographs of the upper thoracic spine was（7.20±2.04）°.We should bend the steel plate or rob to a suitable concave angle before the fixation in the surgery.