| Objective:To evaluate the relationship between atlanto-axial fusion angle and postope rative subaxial subluxation following atlanto-axial arthrodesis in patients with rheumato id arthriti,and clarify the characteristics of SAS after surgery,and to determine the opti mal fusion angle for preservation of physiologic subaxial alignment.Summary of Background Data:The occurrence of SAS has often been observe d after the atlantoaxial arthrodesis in patients with rheumatoid arthritis.Many author s have noted that excessive correction of the atlanto-axial angle,resulting in the development of postoperative SAS.However,there have been few previous repor ts on the correlation between radiographic parameters and the incidence of posto perative SAS.Therefore,a retrospective study of 32 patients who underwent surgi cal treatment for cervical spine of rheumatoid arthritis were conducted.Methods:32 patients with cervical spine involvement in rheumatoid arthritis who underwent transarticular screw fixation?Magerl technology?between September2010 and August 2017 in The 98th Military Hospital were retrospectively studied.Two patients died from causes unrelated to this procedure within three years afte r surgery.Ultimately,30 of 32 patients had sufficient clinical data for the analys is.The patients included 23 females and 7 males.The duration of RA ranged fr om 5 to 30 years,with a mean duration of 12.5 years.The average patient age at surgery was 50.6 years?range 35-70 years?.The research included 7 males an d 23 females,the average age is 50.6 years?35-70 years old?.Thirty patients wi th AAS treated with surgery were reviewed.30 patients with atlantoaxial subluxa tion were evaluated and all the postoperative imaging data were obtained after th e surgery.The cervical sagittal parameters were measured on X-ray,including C1-C2 angle and C2-C7 angle.The production and development of SAS after the sur gery was studied by the annual CR imaging data.Results:SAS was observed 3.6±0.8 years?range 2.0–7.0 years?after the surgery.The occurrence of SAS after atlanto-axial posterior screw fixations was observed in5 patients?SAS P+group?.SAS was observed in 3 of 16 patients after transarticula r screw fixation and 2 of 14 after C1 lateral mass–C2 pedicle screw fixation.In the pos toperative measurements,there was a statistically significant difference in the C2–C7 angle with and without SAS?p<0.05?.There was no statistically significant dif ference in the SAS incidence between the two procedures?p=0.567?.There were als o no statistically significant differences in the preoperative C1–C2 and C2–C7 angles bet ween the two surgical procedures.On the contrary,there were statistically significant di fferences in the postoperative C1–C2 and C2–C7 angles between the two surgical proce dures?p<0.05?.The difference between pre-and postoperative atlantoaxial angles in t he SAS+group and SAS-group has no statistically significant?p>0.05?.Postoper ative C2–C7 angle were significantly different between patients with and without posto perative SAS.The C2–C7 angles changed significantly between pre-and postoperativ e periods in the SAS P+group?p<0.05?,but not in the SAS P-group?p>0.05?.Ther e were no significant differences in age,gender or the duration of RA between the SA S P+group and the remaining 25 cases.Conclusion:The excessive correction of atlantoaxial fusion angle is one of the i mportant factors that affect the development of subaxial subluxations after the su rgery in patients with rheumatoid arthritis,and the optimal atlantoaxial fixation a ngle should be based on the comprehensive consideration of the original situation and the overall cervical sequence. |
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