The study was designed as prospective, randomized, controlled trial. The patients who meet the eligibility requirements will be randomized into two groups in a 1:1 ratio to fluoroscopy and ultrasound+fluoroscopy. Before the procedure, all patients will be scanned with ultrasonography to examine the caudal region morphology.~Processing time will be recorded during injection. Fluoroscopy time (sec) and kerma-area product (μGy) automatically measured by the fluoroscopy device will be used to evaluate the radiation exposure.~Pre-procedural visual analogue scale (VAS) scores and Oswestry Disability Index (ODI) values were noted all the patients.
The primary purpose of this study is to asses the effect of caudal epidural injection guided by a combination of ultrasound and fluoroscopy on the duration of the procedure and the amount of radiation exposed during the procedure, compared to the application of only fluoroscopy-guided.~Secondary aims are to reveal the presence of structural variations that prevent injection by examining the morphology of the sacral hiatus by ultrasonography.