影像学方法研究改良经椎弓根楔形截骨应用于第7颈椎的可行性

Feasibility analysis of modified pedicle subtraction osteotomy for cervical 7 by evaluating radiographic results

目的通过研究改良经椎弓根楔形截骨（PSO）应用于C7的可行性,探索后路单节段大角度截骨术式在改善重度颈胸段后凸畸形的应用前景。方法回顾性研究20122015年在第二军医大学附属长征医院行颈胸段CT二维重建的健康体检人员的影像学资料。利用矢状位二维重建图像,采用不同PSO截骨术式对C7进行模拟截骨。测量截骨角度以及术中对相邻节段关节突的必要切除长度;通过计算C6椎弓根下缘与T1椎弓根上缘的距离,预判矫形后C7、C8神经根是否受压;通过统计截骨线与C6、T1椎弓根的接触情况,预判术中相邻节段椎弓根是否受损。并将结果用于分析截骨术式的可行性。结果共100名健康体检者的颈胸段CT三维重建影像学资料纳入样本,测量得改良PSO截骨应用于C7可改善（60.0±6.2）°的后凸畸形,术中需至少切除C6下关节突（4.7±2.1）mm、T1上关节突（6.5±2.6）mm。通过影像学方法模拟截骨矫形后,C7相邻椎体椎弓根间C7、C8神经根不受卡压的比率为74%,截骨中椎体相邻节段椎弓根不受损伤的比率为82%,该术式在理论上可行的比率为68%。结论影像学研究结果表明,改良PSO截骨技术应用于C7具有较高的理论可行性,在重度颈胸段后凸畸形的治疗中具有一定的研究前景。

Objective To illustrate the prospects of osteotomy for severe cervicothoracic kyphosis in single segment via posterior approach by exploring the feasibility of modified pedicle subtraction osteotomy（ PSO） technique for the C7 by evaluating radiographic results of healthy volunteers. Methods A retrospective study on radiographic data of CT two-dimensional reconstruction on healthy volunteers in our hospital from 2012- 2015 was conducted. On the sagittal plane,we simulate osteotomy with PSO technique and document the angle of osteotomy and the necessary excision length of facet joints in adjacent segments. Pre-judge whether the C7 and C8nerve roots would be compressed or not by calculating the distance between C6 pedicle and T1pedicle; Pre-judge whether the pedicles of adjacent segments would be damaged by researching the relationship between oteotomy line and C6,T1 pedicles. And we use this result to illustrate the theoretical feasibility of modified PSO technique. Results A total of 100 healthy cervical CT reconstruction imaging data was included in the study. We measured that the modified PSO technique can improve the angle with（ 60. 0 ± 6. 2） mm and（ 4. 7 ±2. 1） mm of C6 inferior facet and（ 6. 5 ± 2. 6） mm of T1 superior facet need resection during the surgery. The results of simulating osteotomy show that the ratio of C7 and C8nerve compression after osteotomy was 74%,and the ratio of adjacent vertebral segment pedicle without injury after complete osteotomy was 82%. Theoretically,the feasible ratio of osteotomy was 68%. Conclusion The radiographic measurements conclude that the modified PSO technique for C7 segment is feasible,and it may a promising method for severe cervicothoracic kyphosis.