OBJECTIVETo evaluate the effect of preoperative factors on the function of the cervical spine after Bryan artificial disc replacement.

METHODSFifty patients who underwent cervical disc replacement from December 2003 to January 2006 were investigated. The preoperative factors such as long course of disease, lose of motion or disc height at the operation level were evaluated for their effects on the motion of the operated disc and clinical results at the time of final follow-up. There were 35 males and 15 females. Thirty-nine patients received one-level disc replacement, 11 patients received two-level disc replacement. The age of patients was from 25 to 73 years, average was 49 years.

RESULTSUntil January 2009, 50 cases of all the 53 patient who got operation for more than 3 years were followed up. The follow up period was from 36.0 to 55.6 months, which showed a skewed distribution, with a median of 41.9 months. The patients, who got neural syndrome for more than 3 years, would have worse JOA recovery rate through the surgery compared with the patients who got neural syndrome less than 3 month. As for radiographic results, the preoperative range of movement (ROM) at the implanted disc spaces was 10.4 degrees +/- 5.0 degrees which had significant correlation with the most recent follow-up ROM which was 8.6 degrees +/- 4.8 degrees (r = 0.325, P < 0.05). The group which height ratio of the operative disc and the adjacent discs was less than 0.87 would have worse JOA recovery rate and range of motion at operated level at the most recent follow-up than the group more than 0.87 with statistical significance.

CONCLUSIONSFor the patients with cervical spondylosis or cervical disc herniation who get nervous syndrome for more than 3 years, will have worse JOA recovery rate through the surgery, so the patient should get the operation in time to achieve better improvement. When the operated level is severe degenerated, the motion of the replaced disc and the clinical results is dissatisfied at the time of final follow-up, so it is the relative contraindications for the cervical disc replacement.