Global Variation in Fusion Assessment Practices Following Anterior Cervical Discectomy and Fusion

Study Design Cross-sectional survey. Objectives To characterize global variation in imaging modalities, fusion criteria, and decision-making practices for assessing fusion following anterior cervical discectomy and fusion (ACDF). Methods A modified 30-item survey using Delphi-informed methodology was distributed to global cervical spine experts selected by research impact. Response rate was 40%. Items addressed surgeon demographics, preferred fixation and interbody techniques, bracing protocols, imaging strategies, and perceived strength of evidence for fusion assessment criteria. Responses were analyzed descriptively. Results Substantial variation was observed in imaging preferences and fusion criteria. Most surgeons preferred plate fixation for both 1–2 level ACDF (mean 71%) and 3–4 level ACDF (mean 92%). Metallic cages were the most frequently used interbody devices, with mean preferences of 40% for 1–2 levels and 42% for 3–4 levels. Fusion status and patient satisfaction were the primary determinants of follow-up duration. Flexion–extension radiographs and CT were the most frequently used modalities. The strongest endorsed criteria for fusion were <1 mm interspinous motion, <5° angular motion, and graft bridging bone ≥2 mm on CT, though up to 20% of surgeons still rated these measures as moderate or poor evidence. While 77.8% endorsed the need for standardized criteria, only half were aware of existing guidelines. Conclusions Although commonly used measures such as <1mm interspinous motion, <5° angular motion, and CT-based extra-graft bridging bone are supported by prior studies, the absence of standardized diagnostic criteria limits confidence in their validity and highlights the urgent need for a universally accepted, evidence-based standard for fusion after ACDF.