When the dr. and team is looking into the stomach area with the ERCP they take pictures of what is causing the problem. Once it was determined that there were stones in the bile duct, they insert an instrument into the same pipe through the mouth down into the stomach, then up the bile duct. At the end of the instrument there is a tiny claw that grabs one stone, then they remove the instrument and the stone, then re do the procedure until all the stones are gone. My urine was very brown for about 5 days.