Mirizzi syndrome type I occurs when a gallstone lodges in the gallbladder neck, infundibulum, or cystic duct and externally compresses the common hepatic duct — without fistula formation between the gallbladder and the bile duct.
Mirizzi type I accounts for 11% of Mirizzi syndrome cases. The external compression of the common hepatic duct arises entirely from the impacted stone and surrounding inflammation, with no fistula formation — the defining feature that sets this type apart.
Management is surgical; the operative approach involves a form of cholecystectomy selected according to the local anatomy encountered — the full structured protocol specifies the operative decision pathway.