A method of performing a surgical procedure with a surgical tool assembly includes inserting a surgical tool into a passage of a patient. The surgical tool can include a main unit and a first rigid sheath. The main unit includes an inner tube that is received within an outer tube. The first rigid sheath removably receives the main unit. The surgical tool can be removed from the passage of the patient, and the first rigid sheath can be completely removed from the main unit. A second rigid sheath having a different shape from the shape of the first rigid sheath can then be removably attached to the main unit instead of the first rigid sheath.
