Jaw structure for electrosurgical instrument and method of use

Abstract

An electrosurgical medical device and technique for creating thermal welds in engaged tissue that provides very high compressive forces. In one exemplary embodiment, at least one jaw of the instrument defines a tissue engagement plane carrying first and second surface portions that comprise (i) an electrically conductive material and (ii) a positive temperature coefficient (PTC) material having a selected increased resistance that differs at each selected increased temperature over a targeted treatment range. One type of PTC material is a doped ceramic that can be engineered to exhibit a selected positively sloped temperature-resistance curve over about 37° C. to 100° C. The 70° C. to 100° C. range can bracket a targeted 'thermal treatment range' at which tissue welded can be accomplished. The engineered resistance of the PTC matrix at the upper end of the temperature range will terminate current flow through the matrix. In one mode of operation, the engagement plane cause ohmic heating within tissue from Rf energy delivery tissue PTC matrix is heated to exceed the treatment range. Thereafter, energy density in the engaged tissue will be modulated as the conductivity of the second portion hovers within the targeted treatment range to thereby provide optical tissue heating for purposes of tissue welding.