Introduction of a "safety zone" for the safety of laparoscopic cholecystectomy.

Anatomic variations of the biliary tract were found in 18 cases of 600 patients (3.0%) undergoing laparoscopic cholecystectomy. All bile duct anomalies were confirmed preoperatively by endoscopic retrograde cholangiography. In every case, the cystic duct and cystic artery were exposed in a "safety zone" near the gallbladder neck in Calot's triangle. Laparoscopic cholecystectomy was successfully performed on all 18 cases. Intraoperative cholangiography clearly demonstrated the anatomic variations in all cases, unequivocally identified the cystic duct, and confirmed the absence of bile duct injury. Preoperative endoscopic retrograde cholangiography and intraoperative cholangiography, which have been performed routinely in all patients, improve the safety of laparoscopic cholecystectomy. Moreover, the observance of the essential rule of "keep operating in the safety zone" protects against inadvertent complications, especially against bile duct injury during laparoscopic cholecystectomy. Laparoscopic cholecystectomy was thus successfully performed on all 600 cases in the present series, except for three cases, which were converted to open surgery (conversion rates, 0.5%), because of pin-hole bleeding on the portal vein in our first case of 600, and severe adhesion in two (46th and 302nd) cases.