Comparison of the Clinical and Radiographic Results Between Cervical Artificial Disk Replacement and Anterior Cervical Fusion: A 6-Year Prospective Nonrandomized Comparative Study.

STUDY DESIGN

Prospective nonrandomized comparative study.

OBJECTIVE

To compare the long-term clinical and radiographic results of cervical artificial disk replacement (CADR) and anterior cervical discectomy and fusion (ACDF), and to provide our evidence if CADR could reduce adjacent segment degeneration (ASD).

SUMMARY OF BACKGROUND DATA

CADR is widely used in spine surgery today. Despite the short-term results of it having been ascertained, the long-term results are still under observation. Meanwhile it is still debatable if CADR could reduce ASD in the long run.

MATERIALS AND METHODS

Sixty-three patients with cervical myelopathy who underwent CADR (28) or ACDF (35) with a minimum follow-up of 68 months were included. Japanese Orthopaedic Association score, neck disability index, and Odom's scale were used to evaluate the clinical outcomes. Radiographs, computed tomography, and magnetic resonance imaging were used to evaluate the radiographic outcomes.

RESULTS

Both CADR and ACDF groups showed significant improvement on Japanese Orthopaedic Association scores and neck disability index, and there was no significant difference between the 2 groups. The sagittal alignment was maintained for both the groups. The C2-C7 range of motion had no significant change for CADR group, whereas it significantly decreased for ACDF group. The range of motion at index level of CADR patients decreased from 9.5±3.7 degrees before surgery to 7.0±3.0 degrees at 3 months after surgery (P<0.001), and it was maintained to 6.6±4.1 degrees at last follow-up without significant decrease (P=0.448). We used radiographic data to evaluate ASD and we found the incidence of ASD was significantly lower for CADR group than ACDF group.

CONCLUSIONS

The clinical and radiographic results of CADR over 6-year follow-up are basically satisfying. Compared with ACDF, CADR could better preserve physiological motion and biomechanics of cervical spine, and reduce the occurrence of ASD.