The classification of mirizzi syndrome is:

Classification of Mirizzi syndrome: Csendes and Mc Sherry Type I: External compression of the common duct because of a stone impacted at the neck of the gallbladder or at the cystic duct. Type II: Cholecysto Biliary fistula involving less than one-third of the circumference of the common duct Type III: Cholecysto Biliary fistula that involves up to two-thirds of its circumference cholecysto biliary fistula Type IV: Cholecysto Biliary fistula with complete destruction of the entire wall of the common duct Ref: Turk J Gastroenterol 2008; 19 (4): 258-263.