Abstract: 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 C₈ nerve roots would be compressed or not by calculating the distance between C₆ pedicle and T₁ pedicle;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 C₈ nerve 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.