Instability in the distal-to-stabilization segments after occipito-cervical fixation in patients with rheumatoid arthritis: the challenge of spine surgery.

Rheumatoid arthritis (RA) is a chronic, autoimmune inflammatory disease mainly affecting the joints and periarticular soft tissues. C1-C2 instability is particularly observed, which causes a serious neurological risk. In such cases, surgical treatment, occipitocervical fixation (OCF), is considered. However, complications are inevitable. In some patients, we observe instability in the distal-to-stabilization segments after OCF. The aim of this article was to evaluate stability in the distal-to-stabilization segments after OCF in patients with RA. 33 patients with RA were retrospectively included. Instability occurred in 19 patients in the distal-to-stabilization segments after OCF. Postoperatively, the C2-C7 Sagittal Vertical Axis (C2-C7 SVA) distance was significantly lower in patients with instability than in patients without instability: 10 mm (IQR:7-21) vs. 25 mm (IQR: 10-31); p = 0.042. In logistic regression analysis, we found that an increase in the postoperative C2-C7 SVA by 1 mm is associated with an 8-11% decrease in the odds of instability. An increasing incidence of instability in the distal-to-stabilization segments after OCF was observed in patients with RA. Furthermore, a relationship between C2-C7 SVA after OCF was also found in patients with RA. However, further research is needed in this area.