Purpose <p>This study aimed to evaluate the applicability and technical feasibility of magnetic resonance imaging (MRI) and ultrasonography (US) fusion-guided transforaminal epidural steroid injection (TFESI) in patients with lumbar disc herniation (LDH) leading to radiculopathy, who are unresponsive to conservative treatment.</p> Methods <p>This retrospective study included 21 patients aged 18–65 years who underwent MRI-US fusion-guided TFESI for LDH-induced radiculopathy. Patient data, including demographic characteristics, body mass index (BMI), fluoroscopy duration, radiation dose, and procedure success, were analyzed. Success was defined by the contrast-spread pattern during the procedure. Statistical analyses were performed to identify factors predicting procedural success.</p> Results <p>The MRI-US fusion-guided TFESI procedure was successful in 81% of patients. Successful outcomes were significantly associated with younger age (≤ 56 years, <i>p</i> &lt; 0.001), lower BMI (≤ 28&#xa0;kg/m², <i>p</i> &lt; 0.001), shorter fluoroscopy duration (&gt; 4.9&#xa0;s, <i>p</i> &lt; 0.001), and lower radiation dose (&gt; 3.7 mGy, <i>p</i> &lt; 0.001). A positive correlation was observed between age and radiation dose (<i>p</i> = 0.030), as well as between BMI and radiation dose (<i>p</i> = 0.049).</p> Conclusion <p>MRI-US fusion-guided TFESI is a feasible and safe technique with a high success rate and low radiation exposure in patients with LDH-induced radiculopathy. Younger age, lower BMI, shorter fluoroscopy duration, and lower radiation dose are significant predictors of procedural success. This technique may enhance spatial orientation during the procedure, potentially improving outcomes particularly in younger patients with lower BMI.</p>