[Early effectiveness of discover cervical artificial disc replacement in treatment of cervical spondylosis].

Objective: To investigate the early effectiveness of the Discover cervical artificial disc replacement in treating cervical spondylosis.

Methods: Qualified for the selective standard, 24 patients with cervical spondylosis were treated between March 2010 and March 2011. Of 24 patients, 13 patients underwent anterior cervical decompression and fusion (ACDF) (ACDF group, between March 2010 and September 2010) and 11 patients underwent Discover cervical artificial disc replacement (CADR group, between September 2010 and March 2011). There was no significant difference in gender, age, disease duration, lesions typing, and affected segments between 2 groups (P > 0.05). The operative time, blood loss, and complications were recorded. Japanese Orthopaedic Association (JOA) scores, Neck Disability Index (NDI) scores, and Odom's scores were used to evaluate the postoperative effectiveness. In CADR group, the cervical range of motion (ROM) in all directions, and prosthesis eccentricity were measured before and after operation.

Results: Symptoms disappeared and no complication occurred after operation in the patients of 2 groups. The patients were followed up 12 to 18 months (mean, 15.3 months) in ACDF group and 6 to 12 months (mean, 9.6 months) in CADR group. The NDI scores in CADR group were significantly higher than those in ACDF group at 1, 3, and 6 months (P < 0.05), but no significant difference was observed in JOA score improvement rate between 2 groups (P > 0.05). According to Odom's score at last follow-up, the results were excellent in 6 cases, good in 4 cases, and fair in 3 cases with an excellent and good rate of 76.92% in ACDF group, and were excellent in 9 cases, good in 1 case, and poor in 1 case with an excellent and good rate of 90.91% in CADR group, showing no significant difference (chi2 = 3.000, P = 0.223). The patients in CADR group had significant limit of cervical joint ROM in flexion and extension and right bending at 1 month (P < 0.05), but cervical joint ROM restored after 3 months. The ROMs of left bending at 3 months and 6 months were bigger than preoperative value (P < 0.05). Meanwhile, ROM in left bending were bigger than that in right bending in replaced segment and upper segment (P < 0.05), and the ROM difference between left bending and right bending in upper segment was 2 times higher than that in the replaced segment; a marked linear correlation (P < 0.05) existed between the ROM difference and prosthesis eccentricity, and prosthesis bias had bigger ROM in lateral bending.

Conclusion: Discover cervical artificial disc replacement for treatment of cervical spondylosis can provide a good effectiveness and cervical postoperative movement function. As a new prosthesis, it has some merits such as simple operative steps and less complications.