Comparative Assessment of Cervical Range of Motion after Artificial Disc Replacement versus Fusion across Different Levels

Abstract

Background: Cervical degenerative disc disease is most commonly treated with surgery called anterior cervical discectomy and fusion (ACDF); this may reduce the cervical motion and put more stress on adjacent cervical levels. Motion preservation surgical options have also become available, such as Artificial Cervical Disc Replacement (ACDR), but local comparative data on the postoperative cervical range of motion (ROM) is sparse.

Objective: To compare postoperative cervical ROM and clinical outcomes between patients undergoing ACDR and ACDF at different cervical levels.

Methods: Patients who had undergone single-level ACDR or ACDF were identified and their medical records examined from January 2023 to December 2025. Ten patients matched with ACDR patients, and 20 matched patients with ACDF, were included. The range of motion (ROM) of the cervical spine was determined both globally and segmentally by flexion-extension radiographs. Visual Analogue Scale (VAS) and Neck Disability Index (NDI) were used to assess pain and functional outcomes. Data was analyzed using SPSS version 26 and the p<0.05 was considered statistically significant.

Results: The postoperative global ROM was significantly larger in the ACDR group than in the ACDF group (38.7 ± 4.8 vs 28.6 ± 5.1 degrees; p<0.001). In ACDR patients, too, the preservation of segmental ROM was significantly better (7.2 ± 1.4 degrees vs 1.3 ± 0.5 degrees; p<0.001). Motion of adjacent segments was significantly higher in ACDF patients compared to the non-ACDF group (11.4 ± 2.2 vs 8.1 ± 1.3 degrees p=0.002). There was significant improvement in VAS and NDI scores for both groups.

Conclusion: ACDR has shown itself to be superior to ACDF in preserving cervical motion, but equal in producing clinical improvement. In certain patients with cervical disc disease, a motion-preserving surgery may provide biomechanical benefits.