Abstract: An embodiment of the invention includes an electrosurgical jaw structure that carries cooperating PTC bodies in both series and parallel circuit components for controlled RF energy application to engaged tissue to effectively weld tissue.

Abstract: An electrosurgical instrument that allows precise modulation of active Rf density in an engaged tissue volume. The working end of the instrument has a tissue-contacting surface of a conductive-resistive matrix that is variably resistive depending on its temperature. The matrix comprises a positive temperature coefficient (PTC) polymeric material hat exhibits very large increases in resistivity as any local portion increases beyond a selected temperature. In a method of use, the polymeric PTC material senses the temperature of engaged tissue in a manner akin to pixel-by-pixel sensing and thereby changes its resistance in a corresponding pixel-by-pixel manner. The instrument further carries cooling means to cause accelerated thermal relaxation of the PTC matrix during use to make the engagement surface highly responsive to temperature changes that in turn alter the matrix between being electrically conductive and electrically resistive.

Abstract: A working end of a surgical instrument that carries first and second jaws for delivering energy to tissue. In a preferred embodiment, at least one jaw of the working end defines a tissue-engagement plane that contacts the targeted tissue. The cross-section of the engagement plane reveals that it defines a surface conductive portion and an elastomeric body portion. The elastomeric body portion is adapted to flex, deflect and extend laterally when engaging tissue to atraumatically engage tissue at the edges of the working end to create a smooth transition between welded tissue and undamaged tissue. The jaws can further carry a variably resistive matrix of a temperature-sensitive resistive material or a pressure-sensitive resistive material. An interior of the jaw carries a conductive material or electrode that is coupled to an Rf source and controller.