Mean baseline and 1-year PRO scores from patients undergoing surgery for anterior cervical discectomy and fusion (ACDF) and their respective MCID threshold values.

<p>(<b>A</b>) NDI, (<b>B</b>) VAS, (<b>C</b>) PCS PRO measures demonstrated patients’ clinically meaningful and statistically significant improvement 1 year post-surgery. (<b>D</b>) MCS values did not vary significantly. On average, all patients presented high MCS values (very good mental condition) at baseline and 1 year post-surgery. The overall mean change scores were: NDI −14.41±12.09 (p<0.001), VAS −3.34±2.67 (p<0.001), PCS 7.23±9.01 (p<0.01) and MCS 0,38±0.02 (p: 0.85). The MCID threshold score for each PRO measure was: NDI 15.85, VAS 1.95, PCS 42.54 and MCS 53.55. HTI was chosen as the anchor for the calculation of the MCID threshold values. MDC represents the chosen anchor-based approach. Abbreviations: NDI, Neck Disability Index; PCS, Physical Component Summary of the Short Form of the SF-36; MCS, Mental Component Summary of the Short Form of the SF-36; VAS, Visual Analog Scale; MCID, Minimum Clinically Important Difference; PRO, Patient-Reported Outcome; **, p<0.01; ***, p<0.001.