Rheumatoid vertical and subaxial subluxation can be prevented by atlantoaxial posterior screw fixation

Abstract

Purpose Literature has described a risk for subsequent vertical subluxation (VS) and subaxial subluxation (SAS) following atlantoaxial subluxation in rheumatoid patients; however, the interaction of each subluxation and the radiographic findings for atlantoaxial fixation has not been described. The purpose of this study was to evaluate the effects of two different posterior atlantoaxial screw fixation on the development of subluxation in patients with rheumatoid atlantoaxial subluxation. Methods Between 1996 and 2006, rheumatoid patients treated with transarticular fixation and posterior wiring (TA) or C1 lateral mass-C2 pedicle screw fixations (SR) in the Nagoya Spine Group hospitals, a multicenter cooperative study group, were included in this study. VS, SAS, craniocervical sagittal alignment, and range of motion (ROM) at the atlantoaxial adjacent segments were investigated to determine whether posterior atlantoaxial screw fixation is a prophylactic or a risk factor for the development of VS and SAS. Results The mean follow-up was 7.2 years (4-12). No statistically significant difference was observed among the patients treated with either of the procedure during the follow-up period. Of 34 patients who underwent posterior atlantoaxial screw fixation, SAS was observed in 26.5 % during the follow-up period; however, VS was not observed. Postoperative C2-7 angle, and Oc-C1 and C2-3 ROM were significantly different between patients with and without postoperative SAS. The incidence of SAS was 38.9 % for TA and 12.5 % for SR; statistically significant differences were observed in the postoperative C1-2 and C2-7 angles, and C2-3 ROM. Conclusions Atlantoaxial posterior screw fixation may be an appropriate prophylactic intervention for VS and SAS if the atlantoaxial joint develops bony fusion following physiological alignment. Compared to TA, SR provided optimal atlantoaxial angle and prevented lower adjacent segment degeneration, thereby reducing SAS.

Endoscopic transnasal anterior release and posterior reduction without odontoidectomy for irreducible atlantoaxial dislocation

“…Reduction is achieved sequentially by the pull strength of instruments via the posterior approach. Another advantage of the posterior approach is the realignment of the atlantoaxial joint, which can prevent subaxial degeneration due to misalignment of the cervical spine [26, 27]. In our study, only 1 patient achieved partial reduction, but this did not result in neurological deficits.…”

Retro-odontoid cystic mass treated by laminectomy and C1-C2 fixation

“…It is also reported that posterior fixation of such degenerative tissue would reduce repetitive mechanical stimulation, thereby inhibiting stress on the spinal cord and reducing the inflammation which had produced the degenerative lesions. 9 10 Similar to degenerative cysts, retro-odontoid hypertrophy of soft tissue mass in a non rheumatoid patient with atlantoaxial subluxation has been reported to decrease after posterior fixation. 11 12 13 14 15 Nevertheless, the surgical procedure is appropriate for no neurologic symptoms and the small cystic mass.…”

Distal Junctional Disease after Occipitothoracic Fusion for Rheumatoid Cervical Disorders: Correlation with Cervical Spine Sagittal Alignment

“…Several studies have reported the correlation between the radiographic parameters and the development of SAS in patients with RA who underwent cervical intervention. 18 19 20 21 22 23 With regard to C1–C2 arthrodesis for AAS, several studies have mentioned that the optimal AA angle for C1–C2 fixation is ∼20 degrees. 23 24 Ishii et al reported that overcorrection of the atlantoaxial angle in C1–C2 arthrodesis is strongly correlated with the development of postoperative SAS.…”

“… 20 Yoshida et al reported that decrease in range of motion in the O–C1 segments is a risk factor for postoperative SAS. 21 With regard to occipitocervical fusion, Matsunaga et al reported that in patients with RA, the position of fixation of the occipital bone and axis should be within the range of 0 to 30 degrees, considering the long-term effects on the middle and lower cervical vertebrae. 22 In the present study, the postoperative O–C2 angle was outside the range of 0–30 degrees in only two patients, who did not experience distal junctional disease.…”