[The application of cervical spine arthroplasty with Bryan disc and mid-term clinical and radiological follow-up results].

OBJECTIVE

To study the clinical and radiological outcome of Bryan cervical disc replacement and the degenerative status on adjacent segments.

METHODS

The data of 26 cases of single level disc replacement with minimal 2 years follow-up were reviewed. CLINICAL OUTCOME was assessed with the JOA 17 score scale and Odom's score. Radiological assessment including range of motion and heterotopic ossification of operated level were recorded. Adjacent level degeneration on X-ray and MRI scan at baseline and at follow-up were compared.

RESULTS

(1) CLINICAL OUTCOME: the average JOA score was 16 with 84% improvement ratio at final follow-up in 18 cases of cervical myelopathy. Eight cases of radiculopathy were fully recovered. According to the Odom's criteria 15 cases had an excellent outcome, 7 good, 4 fair, and no case of poor result. (2) On X-ray: The range of motion (ROM) at operated level was 6.9 degrees (2 degrees-12 degrees) at baseline and 7.8 degrees (1 degree-14 degrees) at final follow-up. The heterotopic ossification around the prosthesis was observed in 7 cases and only 1 case lost movement. The average ROM was 5.3 degree in other 6 cases. There was no obvious change of disc height at adjacent levels. (3) On MRI: There was no deterioration of disc degeneration at adjacent levels at final follow-up according to Pfirrmann's classification. There was no further ligamentum flavum impingement into spinal canal observed at adjacent levels but the disc movement slightly increased at both upper and lower adjacent level at final follow-up.

CONCLUSIONS

The motion at operated level is preserved after minimal 2 years Bryan disc replacement with satisfied clinical outcome. The deterioration of disc degeneration at adjacent levels may be postponed.