Is an optical illusion the cause of classical bile duct injuries?

We sought to determine if lateral-inferior traction on the Hartmann pouch could produce bile duct kinking and subsequent misinterpretation of the space on the left side of the bile duct as the hepatobiliary triangle. Once traction was applied, we measured the angle between the cystic duct and inferior gallbladder wall hepatobiliary triangle) in 76 cases, and the angle between the common bile duct and common hepatic duct (porta hepatis "triangle") in 41 cases. The mean angles were significantly different (hepatobiliary triangle mean 68.2°, standard deviation [SD] 16.0°, range 23-109°; porta hepatis "triangle" mean 112.0°, SD 18.4°, range 72-170°; p < 0.01). The ranges, however, overlapped in 26 cases. In many cases, lateral-inferior traction on the Hartmann pouch produced substantial kinking of the bile duct that could easily elicit the illusion that it is the hepatobiliary triangle rather than the centre of the porta hepatis.