Single-stage Anterior Release and Sequential Posterior Fusion for Irreducible Atlantoaxial Dislocation.

STUDY DESIGN

A retrospective study.

OBJECTIVE

To introduce the method of single-stage anterior release and reduction with posterior fusion in irreducible atlantoaxial dislocation (IAAD) and to evaluate the clinical effects of this surgery.

SUMMARY OF BACKGROUND DATA

In previous clinical studies, several techniques have been introduced to manage IAAD. But all these treatments have intrinsic disadvantages. A single-stage anterior release and reduction with posterior fusion can offer a new alternative which can avoid these disadvantages.

METHODS

From January 2003 to January 2009, 22 cases of IAAD were diagnosed consecutively. Anterior atlantoaxial release was performed through anterior retropharyngeal approach, after traction reduction conducted on the monitoring of C-arm fluoroscopy. C1-C2 were then fixed posteriorly and fused by single stage. Neurological status was evaluated using the Japanese Orthopaedic Association scoring system.

RESULTS

All patients were observed for an average of 32 months, ranging from 15 to 40 months. All cases achieved anatomic reduction and solid fusion. The Japanese Orthopaedic Association score of 12 patients with myelopathy improved from 8.3 to 13.9, 6 months postoperatively, and the mean improving rate was 87.5%. No graft or implant-related complications were observed in any patient during the entire follow-up period.

CONCLUSIONS

The method of single-stage anterior release and reduction with posterior fusion is an effective method for management of IAAD, proving its value as a technique for achieving complete reduction with solid bony fusion.