SUMMARY
Objective. To determine the factors, predisposing to development of Mirizzi syndrome; to improve diagnosis and classification of it, taking into account of these factors and possibilities to apply a definite kind of endoscopic or operative treatment.Materials and methods. Retrospective analysis was done for results of treatment of 21 patients with Mirizzi syndrome: Type I in accordance to classification of McSherry (1982) was present in 7 patients, while a Type II - in 14.Results. There was established, that atypia (the variant anatomy) of the ductus cysticus localization predisposes for contact between hepaticocholedochus and a gallbladder of with ductus cysticus, leading to development of Mirizzi syndrome Types I and II. Squeezing (Type I) or fistula (Type II) are observed on any level of hepaticocholedochus. In syndrome of Mirizzi Type II the duct distal to fistula may be not dilated (Subtype IIA) or dilated (Subtype IIB).Conclusion. Atypia (the variant anatomy) of the ductus cysticus duct constitute a factor, promoting development of Mirizzi syndrome. While diagnostic process for Mirizzi syndrome it is necessary to take into account a localization of squeezing of hepaticocholedochus or of fistula, presence of atypia of the ductus cysticus and its stump localization, character of the gallbladder inflammation, quantity and size of calculi. Proposition to include the Types IIA and IIB II in Mirizzi syndrome, depending on the dilation degree present in hepaticocholedochus distally, to the fistula, constitutes a substantiated principle, because it takes into account a possibility to perform endoscopic lithoextraction and to impact the choice of the surgical treatment method.