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Electrically heated surgical cutting instrument

  • US 4,219,025 A
  • Filed: 11/16/1978
  • Issued: 08/26/1980
  • Est. Priority Date: 11/16/1978
  • Status: Expired due to Term
First Claim
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1. A surgical instrument for cutting tissue with simultaneous hemostasis, the instrument comprising:

  • a substrate of electrically insulating material in the form of a blade having a cutting edge, having disposed thereon in the vicinity of the cutting edge an electrically heatable element of electrically conductive material exhibiting a resistance characteristic which varies as a function of the temperature, the heatable element being divided at selected locations into a plurality of independently heatable sections which form segments along said cutting edge and connection means for each segment providing electrical connection to each of said segments at the selected locations, means for independently supplying electrical power thereto along said connection means for maintaining the temperature of each of said segments at substantially constant selected value, said connection means including n+1 conductors for the heatable element wherein n is the number of segments, such that, the connection means for each pair of adjacent segments is shared by a common one of the n+1 conductors;

    logic means for coupling said means for supplying electrical power to each of said segments over said connection means independent of power supplied to an adjacent segment, such that, each may be heated independently, said logic means including exclusive OR logic for each segment, responsive to a reference polarity signal corresponding to the polarity of the power supplied at one of said connection means for the segment for producing selected outputs, means responsively coupled to the logic means for providing power to the segment in opposite electrical sense to the reference polarity signal for the segment or the same electrical sense to inhibit power thereto.

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