Improved technique for rethreading and modifying Cope loop retention catheters

In patients with high proximal biliary obstructions, the standard Cope biliary retention catheter may not drain the proximally obstructed bile ducts. Placing additional side holes proximally in the catheter will usually cut the retention string. We have therefore devised a simple technique for removing the string prior to making the side holes and replacing it, using the stiffening cannula provided with the catheter. The technique has proved successful in 5 cases.