To clarify the characteristics of the clinicopathological factors in cases of atlantoaxial instability due to rheumatoid and to introduce a new method for the treatment of this disease.
Fifteen patients with atlantoaxial instability due to rheumatoid were treated with posterior facet screws to obtain immediate rigid fixation of C(1 - 2). In this series of patients, screw fixation was augmented with an interspinous C(1 - 2) strut graft which was wired in place to provide three-point stabilization and to facilitate bone fusion.
In each patient fixation was satisfactory, and C(1 - 2) alignment and stability were restored without complication due to instrumentation. All patients showed osseous union (a mean follow-up period of 10 months; range 6 - 14 months).
Posterior atlantoaxial facet screw fixation provides immediate three-dimension rigid fixation of C(1 - 2) that is biomechanically superior to wiring or other fixation.