Instrument for cutting, coagulating and ablating tissue

摘要

An instrument for cutting, ablating and coagulating tissue has a rod of ferromagnetic material fusion welded to the base of a conical tip of copper with the rod adjacent the base of the conic being of lesser diameter than the base to provide a region to accept a potted coil of wire about the rod whereby when the coil is connected to a constant current high frequency source the rod and tip are heated to a temperature approaching the Curie temperature of the ferromagnetic rod. As Curie temperature is approached the rod becomes essentially non-magnetic heating decreases to produce a temperature below Curie temperature and the cycle repeats. As a result of the excellent heat exchange interfaces produced by fusion welding the energy delivered to the tissue or other load which may be non-biological is closely controlled by temperature which is self regulated. A ferromagnetic sleeve is placed about the coil to concentrate magnetic flux in the rod. An outer sleeve spaced radially from the ferromagnetic sleeve and of relatively non-heat conductive material extends from the base of the tip away from the tip to provide a handle for the instrument.