Recurrent gall stones blocking bile duct without gall bladder

Well it is a year later since my last post regarding my gall bladder having been removed in 2003 and having recurrent gall stones blocking my bile duct that have to be removed with ERCP.  I have had this procedure done more times than I can count now.  I am taking 1000 mg Ursodial 3X day and that doesn't seem to really help anything.  This year I have gotten pretty sick twice.  Once in March and again in August.  The time in March I had a 3 centimeter stone lodged in the duct.  I had a precautionary ERCP done in July.  There were only a couple of small stones at that time.  I was in and out the same day.  The time in August I had a stone the size of a golf ball stuck in the duct.  I got pretty sick again.  Hospital for 4 days.  The stone was removed and I now have 2 stents placed in the duct.  Stents have not really helped in the past.  They really want me to have the bile duct bypass surgery soon.  It is a major operation and I don't really understand how it is going to fix the problem since it won't stop the stones from forming.  I will really be in trouble if they get stuck after the surgery without ERCP being a possibility then.  I can't seem to find a lot of information on this problem or on the surgery except that the surgery is mostly performed when there is cancer involved.  I do not have any of that.  Just the stones.  It seems very drastic.  It is major surgery and it has a six week recovery.  Does anyone have anything like this or know anything about the surgery i.e., benefits and drawbacks.  Are the pancreas and the liver affected negatively by the bypass?  Please respond if you have any information or had anything similar happen to you.  My experience with the Dr.'s treating me has been good.  I have never had them not respond quickly to my needs in this area.  I do feel really pressured into the surgery though.  I am getting very tired of experiencing this problem and ending up in the hospital every few months though.