Keyhole surgery cannot be guaranteed to be done in every patient with gallstones.
Some people who have stones that have slipped into the bile duct and removal of these stones has not been possible by ERCP usually cannot have laparoscopic surgery, and may require a conventional open operation to remove the gall bladder and the slipped stones in the bile duct.
A laparoscopic operation is done by vision alone using long, narrow instruments - the surgeon does not get to feel the tissues in his hands as in an open operation. If the surgeon's ability to see the organs being operated is impaired due to any reason during a laparoscopic operation, the surgeon may have to stop the laparoscopic operation and proceed with a conventional open operation. Poor vision during laparoscopic surgery may occur due to structural variations within a person's body, and sometimes due to bleeding or malfunction of one of the sophisticated instruments used in a laparoscopic operation.
Converting a laparoscopic gall bladder operation to an open operation may occur in less than 10% of cases, and cannot be considered a "failure". It is done in the interests of safety of the patient, and ensures overall success in the treatment of the problem.