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 (i) a first surface conductive
portion or a variably resistive matrix of a temperature-sensitive resistive material
or a pressure-sensitive resistive material, and (ii) a second surface portion coupled
to a fixed resistive material that coupled in series or parallel to a voltage source
together with the first portion. In use, the engagement plane will apply active
Rf energy to ohmically heat the captured tissue until the point in time that a
controller senses an electrical parameter of the tissue such as impedance. Thereafter,
the controller switches energy delivery to the second surface portion that is resistively
heated to thereby apply energy to tissue by conductive heat transfer.
