Transartikuläre Verschraubung von Atlas und Axis bei chronischer Polyarthritis

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In 45 patients (34 female, 11 male) suffering from rheumatoid arthritis, a transarticular screw fixation was performed to establish stability between atlas and axis. Mean age was 57 (ranging from 31-79 years). Mean history of rheumatoid arthritis was 17 years (3-42 years) before surgery was indicated. The ventral atlantoaxial interval was 11 mm on average. In all patients the joints between atlas and axis were affected only, there being no single case of destruction of the occipito-atlantal joints. There was no invagination of the dens into the posterior cranial fossa. In 17 cases neurological deficits were detected (Ranawat classes II and III). Surgical technique has been thoroughly described. For the first 16 operations, 2.2 mm double-threaded screws were used, where after 3.5 mm cortical I screws were inserted. Autologous bone was placed on the laminae of the atlas and the axis in 37 patients, 21 of which received additional fixation of the bone by means of a cable-cerclage. In 2 operations methylmethacrylate was applied as a spacer between the dorsal arch of the atlas and the spinous process of the axis. Screws alone were inserted in 6 cases. No intraoperative complications were observed. Injuries to the vertebral artery or the dura mater did not occur. Mean follow up in 43 of 45 patients was 28 months (6-62 months). Two pseudarthrosis were observed in patients without additional bone graft. In patients with bone grafting, one pseudarthrosis only occurred as a result of a misplacement of one screw. As long as exact placement of the screws (described in detail) was achieved and bone grafting was applied no pseudarthrosis was observed in 35 cases. There were two cases of screw breakage with 2.2 mm screws, but none with 3.5 mm screws. Revision surgery was not necessary in any of the cases. A preoperative CT-scan is mandatory to establish any abnormal courses of the vertebral arteries (described in the literature), which is a contraindication for this technique, whereas age need not be considered. In contrast to previous techniques, transarticular screw fixation is possible in cases with a split or a missing dorsal arch of the atlas. This technique should be considered, because of its low complication rate, even in cases with increasing instability without neurological deficits, to ease the burden of the patient knowing that a transverse syndrome may result in cases of untreated instability.