Long Term Outcomes of Atlantaxial Fusion with Transarticular Screw Fixation

Methods: Forty two patients were available to review long term results of atlantoaxial transarticular screw fixation. At a previous two year review there were no nonunions and overall good results These patients returned for examination to assess cervical range of motion , neurologic status and clinical function. Radiographs of the spine in flexion and extension were taken to assess fusion status and adjacent segment abnormalities.

Results: Average follow up was 6.5 years (3-10). Average age at fusion was 34.5(18-76). All were treated with transarticular screw fixation and iliac crest bone grafting. Follow up revealed two nonunions (4.8%), both in rheumatoid arthritis patients. These were painless and required no further surgery. This gave a 23% (2/9) nonunion rate in this patient population. One patient was noted to have screw breakage (2.4%). Mild C2-3 disc space narrowing was seen in four patients (9.5%). There was no evidence of instability and none required further surgery. Range of motion of the cervical spine averaged 40 degrees of flexion, 25 extension and 40 degrees rotation both ways. None of the patients suffered any changes in their daily activities from restricted motion. Eight (19%) utilized NSAIDS or non-narcotic analgesic for intermittent neck pain.

Conclusion: This study reveals good long term results for antlantoaxial transarticular screw fixation. Nonunion rate was 4.8% and occurred only in the rheumatiod population. Screw breakage was 2.4%. No further surgery was required and these patients were asymptomatic. It is felt that the enhanced biomechanical stability provided by the transarticular construct was the reason for the late finding of the nonunions. Adjacent segment degeneration was 9.5%, but none required further surgical treatment. The decreased range of motion does not from the fusion does not significantly alter lifestyles in this patient population.