The Effect of Needle Insertion Angle on Contrast Distribution and Treatment Outcomes in S1 Transforaminal Epidural Steroid Injections

"The designed study will examine the effect of oblique entry angles on contrast distribution patterns and treatment outcomes. Therefore, it aims to compare the smallest and largest angles that can be achieved under co-axial imaging at the S1 foramen. For this purpose, patients will be divided into two groups through randomization using a computer program. In the first group, after angling cranially and visualizing the foramen, the needle entry point will be determined. In the second group, after achieving optimal imaging by cranially angling the C-arm fluoroscope, an additional ipsilateral oblique angle will be applied to the fluoroscope.~In this context, Plastaras et al. reported that an angle of 5° ± 5° is the most suitable range for the S1 foramen. Additionally, another study examining dorsal and ventral S1 foramen via tomography images found that the average angle providing the widest view of the dorsal foramen was 26.6° ± 3°. In the current study, no oblique angle will be applied"