"Diagnostic Accuracy of Ultrasound Compared to Epidurography for Epidural Catheter Localization"

The goal of this clinical trial is to evaluate the effectiveness of ultrasound for locating epidural catheters compared to the gold standard, epidurography. This study is focused on patients undergoing major open abdominal surgeries, who often experience moderate to severe pain during the first 24 to 48 hours after surgery. The main questions it aims to answer are: How does the accuracy of ultrasound for detecting epidural catheter placement compare to that of epidurography? Can ultrasound provide a reliable alternative to epidurography in surgical settings where epidurography is not feasible? In this trial, participants will: Undergo a standard epidural analgesia procedure for pain management during their surgery. Have their epidural catheter placement checked using both ultrasound and epidurography. Report their pain levels and any issues with pain control during the immediate postoperative period. The study will assess whether ultrasound can effectively replace epidurography in confirming catheter placement, potentially offering a less invasive and more practical solution in routine surgical environments.