Effect of cervical disc arthroplasty and anterior cervical decompression and fusion on adjacent segment degeneration

Objective: To compare the effect on adjacent segment degeneration after cervical disc arthroplasty (CDA) and anterior cervical decompression and fusion (ACDF) for treatment of cervical spondylosis.

Methods: Between August 2009 and February 2012, 60 cases of single segmental cervical spondylosis accorded with the inclusion criteria were included. Of 60 patients, 28 patients underwent CDA (CDA group) and 32 patients underwent ACDF (ACDF group). There was no significant difference in gender, age, disease duration, pathological type, pathological segment, the time of conservation treatment, preoperative neck disability index (NDI), preoperative Japanese Orthopaedic Association (JOA) score, and degeneration of the adjacent segment and disc between 2 groups (P > 0.05). The NDI and JOA score were used to evaluate effectiveness. The range of motion (ROM) of adjacent segment was measured, and degeneration of the adjacent segment and disc was evaluated according to Kellgren grading system based on X-ray and Miyazaki grading system based on T2-weighted MRI, respectively.

Results: The follow-up time was 24-50 months (mean, 34 months) in 2 groups. All patients had no complication of prosthesis loosening, dislocation, or fracture of plate. The NDI and JOA scores from 12 months after operation were significantly improved compared with preoperative scores in 2 groups (P < 0.05), but no significant difference was found at each time point between 2 groups (P > 0.05). The improvement rate of JOA was 80.68% ± 4.01% in ACDF group and was 79.44% ± 3.76% in CDA group at last follow-up, showing no significant difference (t = -1.237, P = 0.221). And the improvement rate of JOA in 2 groups were excellent. There was no significant difference in ROM and degeneration grading of adjacent segments between at last follow-up and at pre-operation in 2 groups (P > 0.05), and between 2 groups at pre-operation and at last follow-up (P > 0.05). The degeneration grading of disc at last follow-up showed significant difference in 2 groups compared with preoperative ones (P < 0.05), but no significant difference was found between 2 groups (Z = 0.132, P = 0.895).

Conclusions: Both CDA and ACDF can achieve good effectiveness in treating cervical spondylosis, but CDA can not significantly slow down the degeneration of adjacent segment disc.