Clinically Significant Changes in Global Cervical Range of Motion Following Anterior Cervical Discectomy and Fusion: A Systematic Review.

BACKGROUND

There remains no clear consensus regarding expected range of motion (ROM) loss after anterior cervical discectomy and fusion (ACDF) across varying level constructs. This systematic review aimed to evaluate changes in cervical ROM and the correlation between ROM and patient-reported outcomes measures (PROMs) following single-level and multilevel ACDF.

METHODS

A literature search was conducted across PubMed, Embase, and Scopus databases, spanning from their inception to July 2025, in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria consisted of human comparative studies reporting baseline and postoperative cervical ROM across single and multilevel ACDF. The Methodological Index for Nonrandomized Studies criteria were used to assess study quality. Primary outcome measures consisted of changes in cervical ROM from baseline after surgery. Secondary outcome measures included the modalities used to measure ROM and correlations between changes in changes in ROM and PROMs from baseline to final follow-up.

RESULTS

Ten studies (7 Level II, 3 Level III) involving 832 patients (1- to 4-level ACDF) with mean follow-up ranging from 3 to 38 months were included. ROM was assessed through radiographs (5), electromagnetic tracking (2), computed tomography modeling (1), inclinometry (1), and linkage devices (1). In single-level ACDF, sagittal ROM changes ranged from -15.0% to +19.5%, with 6 of 7 studies reporting stable or increased motion. Lateral bending (+20.2% to +23.3%) and rotation (+7.3% to +13.7%) consistently increased on dynamic analysis. In 2-level fusions, sagittal ROM changes ranged from -33.4% to +9.1% (6 decrease, 3 increase). In 3-level to 4-level fusions, changes ranged from -49.1% to +36.4%. Radiographic studies consistently reported ROM reductions in 2+ level fusions, whereas dynamic analyses demonstrated preserved baseline ROM. All studies showed significant improvements in Neck Disability Index and Visual Analogue Scale neck pain, which correlated weakly or nonsignificantly with ROM changes.

CONCLUSION

Single-level ACDF does not significantly reduce cervical ROM from baseline. In multilevel fusions, a discrepancy exists: radiographs show modest reductions, while dynamic motion analyses suggest that baseline ROM is preserved. Dynamic motion analyses provide a more clinically accurate representation of mobility changes following single-level and multilevel fusions.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.