Electrosurgical instrument with replaceable cartridge

Abstract

Various embodiments provide an electrosurgical instrument with a disposable electrosurgical cartridge. In one embodiment, the cartridge has first and second energy-delivery surfaces that carry first and second opposing polarity conductors coupled to a voltage source, together with first and second temperature-responsive variable impedance bodies exposed partly in the respective-delivery surfaces. The cartridge further carries a slidable blade member. The temperature-responsive variable impedance bodies are coupled to the voltage source by series and parallel circuitry. In use, the variable impedance bodies are adapted to modulate current flow and ohmic heating in engaged tissue by providing controlled current paths in the tissue and through the variable impedance bodies as the temperature-responsive bodies sense the temperature of adjacent engaged tissue. The engagement surfaces are capable of highly localized modulation of Rf energy application to engaged tissue to provide high and low temperatures, voltage and current in the tissue to create high strength welds.

1 . An electrosurgical assembly for detachable coupling with opposing jaws of a surgical instrument, the assembly comprising:
 a body carrying first and second energy-delivery elements for engaging tissue;   a first polarity electrode exposed in a surface portion of the first energy-delivery element for causing ohmic heating in engaged tissue; and   a temperature-responsive variable resistive body exposed in a surface portion of the second energy-delivery element for modulating energy delivery to adjacent ohmically heated tissue responsive to the temperature of the heated tissue.   
     
     
         2 . An electrosurgical assembly as in  claim 1 , further comprising a second polarity electrode in an interior of the temperature-responsive variable resistive body of the second energy-delivery element. 
     
     
         3 . An electrosurgical assembly as in  claim 1 , further comprising a second polarity electrode exposed in a surface portion of the second energy-delivery element. 
     
     
         4 . An electrosurgical assembly as in  claim 1 , further comprising a temperature-responsive variable resistive body exposed in a surface portion of the first energy-delivery element. 
     
     
         5 . An electrosurgical assembly as in  claim 4 , further comprising a second polarity electrode exposed in a surface portion of the first energy-delivery element. 
     
     
         6 . An electrosurgical assembly as in  claim 5 , wherein the first and second polarity electrodes of the first energy-delivery element are separated by the temperature-responsive variable resistive body. 
     
     
         7 . An electrosurgical assembly as in  claim 1 , further comprising a channel within a surface of at least one of the first or the second energy-delivery elements, the channel configured to receive a slidable blade member. 
     
     
         8 . An electrosurgical assembly as in  claim 1 , further comprising a connector means coupled to the body, the connector means configured to couple the first and second energy-delivery elements to a voltage source. 
     
     
         9 . An electrosurgical cartridge assembly for removable coupling with a surgical instrument having a pair of opposing jaw portions, the assembly comprising:
 a cartridge body having an energy-delivery surface for engaging tissue;   at least one electrode exposed in a first portion of the energy-delivery surface for causing ohmic heating in engaged tissue; and   a temperature-responsive variable resistive body exposed in a second portion of the energy-delivery surface for modulating energy density in adjacent ohmically heated tissue responsive to the temperature of the heated tissue.