Feasibility of helical CT multiplanar reconstruction in evaluation of C2 pedicle screw placement / 中国医学影像技术

ABSTRACT

Objective To evaluate the feasibility of the posterior C2 pedicle screw placement (C2 PSP) by MPR techniques of helical CT.Methods Totally 250 patients (500 sides) who underwent head and neck CTA examination were enrolled.The bony parameters and the arterial parameters were measured after MPR.The bony parameters included pedicle diameter (D),isthmus height (T),internal height (H),and the arterial parameters included medial shiftinglateral (L),neutral (N),medial (M);and the degree of riding included below (b),within (w),above (a).The prevalence of narrow pedicles,high-riding vertebral arteries (HRVA) and the subtypes of IAVA in the general population were calculated,and the statistical analysis between narrow pedicles,HRVA,IAVA and C2 vertebral arteries groove (C2 VAG) injury were performed.Results The rate of narrow pedicles and HRVA were 14.40％ (72/500) and 24.60％ (123/500;x2=141.984,P＜0.001).When it came to the simulation of the C2 PSP inserting,the incidence of C2 VAG injuries was 19.40％ (97/500).In narrow pedicle and HRVA patients,the C2 VAG injuries incidence were higher than that of without narrow pedicle and HRVA patients (both P＜0.001).In 58 sides (58/500,11.60 ％),the narrow pedicles and HRVA occurred simultaneously.There were statistical significance differences of narrow pedicles and HRVA and the C2 VAG injuries in different types of IAVA (all P＜0.001),the subtypes of IAVA M-a consisted most common,which account for 55.56％ (40/72),46.34％ (57/123) and 48.45％ (47/97),respectively.Conclusion Most of the C2 VAG injuries happened in narrow pedicles,HRVA or IAVA M-a type patients.MPR can be used to comprehensively evaluate osseous and arterial parameters,which will provide anatomy foundation to the screw placement of C2 pedicles.