Treatment of irreducible old atlantoaxial subluxation with cable-dragged reduction and cantilever beam internal fixation.

STUDY DESIGN

Retrospective case series study of surgical outcome for 21 atlantoaxial subluxation patients treated with a new technique, called cable-dragged reduction/cantilever beam internal fixation. Surgery was performed by a single surgeon.

OBJECTIVE

To describe and evaluate the cable-dragged reduction/cantilever beam internal fixation technique for the treatment for old atlantoaxial subluxation irreducible by traction.

SUMMARY OF BACKGROUND DATA

Management of old atlantoaxial subluxation has always been a difficult task. A more effective way to achieve surgical reduction is needed.

MATERIALS AND METHODS

Twenty one patients, aged 31.6 ± 13.3 years (range, 11-67 years), 17 men and four women, with atlantoaxial subluxation that failed to be reduced after 10 to 111 days in traction, underwent posterior cable-dragged reduction/cantilever beam internal fixation surgery. Frankel classification of neural function before surgery was the following: Frankel B, four patients; Frankel C, five patients; Frankel D, four patients; and Frankel E, eight patients. Plain radiographs, computed tomographic three-dimensional reconstructive images and magnetic resonance images of the cervical spine were obtained at 3, 6, and 12 months after surgery, and each year thereafter. No patient was lost to follow-up, and the follow-up time ranged from 6 months to 4 years. Rate of reduction and C1∼3 fusion, as well as improvement of neural function, were recorded and analyzed.

RESULTS

The average follow-up period was 13.2 months. Radiographic evaluation of the group at follow-up showed 16 complete and five partial reductions, and satisfactory decompression and C1∼3 fusion in all cases. Neural function at the end of the follow-up was Frankel B still in one patient, Frankel C in seven patients, and Frankel E in 13 patients.

CONCLUSION

Cable-dragged reduction/cantilever beam internal fixation is almost as effective for reduction as anterior release but is less invasive and risky. It has similar operative time and blood loss to occipitocervical fusion but avoids arthrodesis of occipitoatlantal joint. It is also suitable for patients with severe myelopathy before surgery. Its major disadvantage is that C3, which is left free in the traditional atlantoaxial fusion surgery, has to be involved in fusion. And it is suitable only for patients with intact posterior arches in C1.