Therapeutic options and results following fixed atlantoaxial rotatory dislocations

Abstract

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.

Fig. 1

Sketch of transoral closed according to Jeszenszky. The image illustrates that the spinous process of the axis is locked by one hand, while the index finger of the other hand presses in counter rotation to the dislocation on the lateral mass of the atlas through the posterior wall of the pharynx

Fig. 2

Lateral X-ray a and CT scan b of the cervical spine of a 22-year-old woman who sustained an upper cervical spine injury, showing a fixed AARD measuring 45° in addition to a posterior arch fracture of atlas. Diagnosis was established 1 week after trauma. Initial treatment consisted of closed reduction and stabilization in halo fixation. Failed reduction led to transfer to our spinal center. Since closed reduction was no longer feasible, an open reduction using the Harms T-plate for temporary fixation was performed 1 month after the accident. Postoperative X-rays (c, d). The plate was removed 3 months later. Follow-up examination after 12 years revealed an asymptomatic patient (VAS: 100). Beginning degenerative signs were seen in the C2/C3 segment (e, f). The dynamic MRI revealed good atlantoaxial rotation of 35° to the right and 28° to the left ( g)

Fig. 3

Range of motion (ROM) of the cervical spine during final follow-up physical examination following different treatment forms. The letters on the left side of the bars indicate the direction of AARD