Surgical cutting instrument having electrically heated cutting edge

Abstract

A surgical cutting instrument includes an electrically heated cutting edge and an automatic control system for maintaining the cutting edge at a constant high temperature for sterilizing the blade, cutting tissue, and cauterizing the incised tissue to reduce hemorrhage from the cut surfaces of the tissues (hemostasis).

I claim: .[.1. A surgical instrument for cutting tissue with simultaneous hemostasis, the instrument comprising: 
     
        said element..]. .[.3.  A surgical instrument as in claim 2 wherein each of said circuit means comprise a plurality of circuit elements and said corresponding section connected in a bridge circuit having first and second pairs of bridge terminals, and including control means coupling said input to the first pair of bridge terminals, and bridge-balance sensing means connected to the second pair of bridge terminals and to said control means for altering the electrical power applied through the bridge circuit to said corresponding section for maintaining the resistance 
     
     
        thereof substantially at a preselected value..]. .Iadd.4.  A hemostatic surgical cutting blade comprising: a cutting blade having a tissue-cutting edge; and   a plural number of heater means disposed along regions of the tissue-cutting edge and each capable of being maintained at a selected temperature range in response to selective cooling of the corresponding region upon contact with tissue being cut such that each of said regions of the tissue-cutting edge is also capable of being maintained at a selected temperature range. .Iaddend. .Iadd.5. A hemostatic surgical cutting blade as in claim 4 wherein:   a cutting blade having a tissue cutting edge; and   each of said plural number of heater means includes electrically conductive material having a resistance which varies as a function of the temperature thereof; and   each of said plural number of heater means conducting electrical current   
     
     
        for heating regions along said edge. .Iaddend. .Iadd.6.  A hemostatic surgical cutting blade as in claim 4 wherein: each of said heater means is capable of elevating the temperature in the corresponding region of said tissue-cutting edge to within the range between 300° C. and 1000° C. .Iaddend. .Iadd.7. A hemostatic surgical cutting blade as in claim 4 wherein:   said cutting blade is formed of non-metallic material. .Iaddend. .Iadd.8. A hemostatic surgical cutting blade as in claim 4 wherein:   
     
     
       said cutting blade includes a ceramic material. .Iaddend. .Iadd.9.  A hemostatic surgical cutting blade as in claim 4 wherein: a cutting blade having a tissue cutting edge; and each of said plural number of heater means includes electrically conductive material having a resistance which varies as a function of the temperature thereof; and   each of said plural number of heater means conducting electrical current for heating regions along said edge. .Iaddend. .Iadd.10. A hemostatic surgical cutting blade as in claim 4 wherein:   each of said heater means is capable of elevating the temperature in the corresponding region of said tissue-cutting edge to within the range between 300° C. and 1000° C. .Iaddend. .Iadd.11. A hemostatic surgical cutting blade as in claim 4 wherein:   said cutting blade is formed of non-metallic material. .Iaddend. .Iadd.12. A hemostatic surgical cutting blade as in claim 4 wherein:   
     
     
       said cutting blade includes a ceramic material..Iaddend. .Iadd.13.  The method of cutting tissue with simultaneous hemostasis comprising the steps of: contacting tissue to be cut with a tissue-cutting edge which has a plural number of regions that are each independently operable at an elevated temperature; and   increasing the power dissipation in each of said regions along the edge which are cooled upon contact with tissue for maintaining the temperature of each of the regions substantially within a selected operating range.   
     
     
        .Iaddend. .Iadd.14.  The method according to claim 13 wherein: in the step of contacting tissue, the temperature of each of said regions of the tissue-cutting edge is independently elevated to within the range between 300° C. and 1000° C. .Iaddend. .Iadd.15. The method according to claim 13 wherein:   in the step of contacting tissue, the temperature of each of said regions of the tissue-cutting edge is elevated in response to independently applied electrical signals. .Iaddend. .Iadd.16. The method according to claim 13 wherein:   in the step of increasing power dissipation, a flow of electrical current from a source of electrical signal is independently controlled in each of the regions along the tissue-cutting edge to maintain the average operating temperature of each region within said range. .Iaddend. .Iadd.17. The method according to claim 13 wherein:   in the step of contacting tissue, the temperature of each of said regions of the tissue-cutting edge is elevated in response to independently applied electrical signals. .Iaddend. .Iadd.18. The method according to claim 13 wherein:   in the step of increasing power dissipation, a flow of electrical current from a souce of electrical signal is independently controlled in each of the regions along the tissue-cutting edge to maintain the average operating temperature of each region within same range. .Iaddend. .Iadd.19. A method of cutting tissue with simultaneous hemostasis comprising the steps of:   contacting the tissue to be cut with a tissue-cutting edge of an elevated temperature; and   establishing the elevated temperature by conducting current along a plurality of independent current paths located along the tissue-cutting edge. .Iaddend. .Iadd.20. A method according to claim 19 wherein:   in the step of establishing the elevated temperature, separately sensing the current in and the voltage across each of said independent current paths; and   altering at least one of the currents in and voltage across each of said independent current paths for maintaining the ratios thereof substantially constant. .Iaddend. .Iadd.21. The method according to claim 17 including:   measuring the resistance of a heating element disposed adjacent said tissue-cutting edge and establishing said elevated temperature of said tissue-cutting edge in response thereto. .Iaddend. .Iadd.22. The method according to claim 19 including:   measuring the temperature of said tissue-cutting edge using thermocouple means disposed near said tissue-cutting edge and establishing said elevated temperature of said tissue-cutting edge in response thereto. .Iaddend.