A sealing and/or cutting instrument having a thermally active surface or element which may be used to seal and then cut tissue, ducts, vessels, etc., apart. The instrument may include a thermally active surface or element comprised of a conductor covered with a ferromagnetic material. The instrument may contact tissue with one or more surfaces comprised of a non-stick material. A sensor in communication with the instrument may be used to monitor a therapeutic procedure and signal when sealing and/or cutting of a tissue is complete.