US Patent 6939494 Method of making ventilation tube

A medical ventilation tube for placement in an opening formed in an anatomical structure, such as the tympanic membrane of the ear, includes a hollow tubular shaft made of a first material having a hardness or durometer to maintain a passage through the shaft when the medical ventilation tube is placed in the opening, and a flange made of a second material having a hardness or durometer less than that of the first material to permit the flange to deform in response to contact with the anatomical structure during removal of the medical ventilation tube from the opening.