Ultrasound Versus Fluoroscopy for Cervical Medial Branch Injections at C3–C6: A Single-Center Retrospective Cohort Study

<b>Objective:</b> Cervical facet joints are prominent sources of chronic neck pain. This single-center retrospective cohort study compared ultrasound (US)-guided and fluoroscopy (FL)-guided cervical medial branch procedures at the C3-C6 levels in terms of technical success and tested for non-inferiority (NI). <b>Methods:</b> Between March 2022 and July 2025, 224 procedures performed at the Adana City Training and Research Hospital, Department of Algology (US, <i>n</i> = 104; FL, <i>n</i> = 120), were analyzed. The primary endpoint was technical success. Secondary endpoints included procedure duration; complications; pain intensity, measured using the Visual Analog Scale (VAS); functional outcomes, assessed with the Neck Disability Index (NDI) at 1, 3, 6, and 12 months; and radiation exposure in the FL group. Propensity score weighting was applied to reduce confounding. The NI margin for technical success was set at -5 percentage points, with α = 0.025. <b>Results:</b> The technical success rates were similar (US: 90.4%, FL: 90.8%; difference: -0.4%, 95% CI: -8.1 to 7.2), but non-inferiority was not statistically achieved (power ≈ 72%). Procedure time was significantly shorter in the ultrasound-guided group compared with the fluoroscopy-guided group (mean difference -5.2 min; 95% CI: -7.5 to -2.9; <i>p</i> < 0.001). No major complications occurred. Both groups demonstrated sustained improvement over 12 months, with VAS scores decreasing from 7.4 at baseline to 4.0 at 12 months and NDI scores decreasing from 41.3 to 29.2. No statistically significant between-group differences were observed for pain intensity (VAS) at any follow-up time point (all <i>p</i> > 0.05). Similarly, functional outcomes (NDI) did not differ significantly between the ultrasound- and fluoroscopy-guided groups throughout follow-up (all <i>p</i> > 0.05). Exploratory analyses using minimum clinically important difference (MCID) thresholds supported the clinical non-inferiority of US. In the FL group, the mean fluoroscopy time was 2.28 min with low radiation doses. <b>Conclusions:</b> Although NI was not statistically confirmed for technical success, US achieved comparable outcomes to FL with shorter procedure times and without radiation exposure. Both modalities provided similar long-term pain relief and functional improvement. US can be considered a safe and effective alternative in experienced hands, but larger multicenter prospective NI trials are needed to confirm these findings.