A method of dilating a paranasal sinus ostium of a patient, which includes inserting a catheter having at least one balloon into a sinus ostium having an ostial wall, inflating the balloon by supplying fluid thereto such that the balloon exerts a force on the ostial wall, determining at least one parameter of the balloon, establishing an amount the balloon can be inflated without fracturing the sinus ostium based at least in part on the determined parameter of the balloon, and dilating the sinus ostium by inflating the balloon to an amount that does not exceed the established amount.
