Therapeutic options and results following fixed atlantoaxial rotatory dislocations

Atlantoaxial rotatory dislocation (AARD) represents a rare pathological condition of the upper cervical spine that is frequently misdiagnosed, leading to a delay in therapy. In a long-term assessment of clinical and radiological results, three different therapeutic options with regard to the length of the dislocation-therapy interval (DTI) were evaluated. Twenty-six patients were treated for AARD from December 1988 until April 2000. Proper diagnosis was established after an average interval of 15 months. Three different therapeutical protocols were followed in order to reduce the dislocation: (1) closed transoral reposition under general anesthesia; (2) temporary transoral fixation utilizing the Harms T-plate; (3) definitive transoral fusion. The eight patients treated by closed reduction had the best pain relief. The average visual analogue scale (VAS) score was 96.6 points, while the rotatory motion of the upper cervical spine, as assessed by dynamic MRI, was 25.3 degrees to each side. The length of the dislocation-therapy-interval (DTI) averaged 1.4 months. A mean VAS Score of 92.3 points was recorded in the ten patients treated with a temporary fixation of C1/C2. In this subgroup the DTI had an average length of 5.3 months. The mean rotation to each side was 13.9 degrees . In the eight patients who underwent definitive fusion the mean VAS score was 60.6 points, while the average length of the DTI was 40.5 months. In conclusion, the clinical outcome and the subjective well-being following AARD deteriorates with increasing length of the dislocation-therapy interval.