[Functional evaluation of the cervical spine after Bryan artificial disc replacement].

OBJECTIVE

To assess the effect of Bryan cervical disc replacement on the function of the cervical spine.

METHODS

Bryan cervical artificial disc replacement was performed in 164 cases from Dec 2003 to Aug 2007, and all the cases were retrospectively followed up. Among them, 1 disc replacement was done in 132 cases, 2 discs in 28 cases and 3 discs in 4 cases with a total number of 200 artificial discs. There were 102 male patients and 62 female patients. Their age ranged from 25 to 70 years old (with an average of 47 years old). All the cases were operated according to the standard procedure for Bryan artificial disc replacement, and immobilized in a cervical collar for 2 weeks after operation. Motion of the replaced disc in sagittal direction, JOA score and satisfaction rate of the patients were followed up and evaluated.

RESULTS

In this group, no acute complications happened during the operation. All patients returned to work 4 to 6 weeks after operation. The postoperative ameliorate rate of JOA score was 56%. Range of motion in sagittal direction of the operated disc was 14.4 degrees before operation, decreased to 5.7 degrees at 1 week after operation , but improved to 14.7 degrees at the time of final follow-up and was not significantly different from preoperative range. Motion in the upper adjacent disc to the replacement level was 10.9 degrees before operation, decreased to 5.5 degrees at 1 week after operation , and improved to 8.2 degrees at the time of final follow-up but was significantly smaller than preoperative range. The satisfaction rate of the patients was 94%. Loosening of the prosthesis happened in 1 case 6 months after operation but remained stable afterwards. Subsidence up to 1 mm occurred in another case 7 months after operation but also remained stable afterwards. Automatic posterior union occurred in 3 cases in which relative small size artificial discs were implanted.

CONCLUSIONS

The clinical outcome of Bryan artificial disc replacement was quite good. Pre-operative range of motion of the cervical spine can be maintained.