Apparatus and method for rapid reliable electrothermal tissue fusion and simultaneous cutting

Abstract

A method of electrothermally fusing together pieces of tissue at an interface and simultaneously cutting the fused tissue along a linear path through the interface, including: compressing the tissue pieces together at the interface sufficiently for fusing the tissue pieces together and for cutting the fused tissue pieces in the linear path through the fused tissue at the interface; delivering an impulse of electrical power of no greater than 4.0 seconds time duration which contains sufficient energy to fuse the tissue pieces together at the interface and to simultaneously cut the fused tissue; converting the electrical power impulse into thermal energy applied at the interface; and regulating the temperature of the thermal energy applied at the interface in a range of 200° C. to 320° C. while fusing and simultaneously cutting the tissue pieces at the interface by controlling characteristics of the electrical power impulse.

What is claimed is: 
     
         1 . A method of electrothermally fusing together pieces of tissue at an interface and simultaneously cutting the fused tissue along a linear path through the interface, comprising:
 compressing the tissue pieces together at the interface sufficiently for fusing the tissue pieces together and for cutting the fused tissue pieces in the linear path through the fused tissue at the interface;   delivering an impulse of electrical power of no greater than 4.0 seconds time duration which contains sufficient energy to fuse the tissue pieces together at the interface and to simultaneously cut the fused tissue in the linear path through the fused tissue at the interface within the time duration of the electrical power impulse;   converting the electrical power impulse into thermal energy applied at the interface to fuse the tissue pieces and to simultaneously cut the fused tissue pieces in the linear path through the interface; and   regulating the temperature of the thermal energy applied at the interface in a range of 200° C. to 320° C. while fusing and simultaneously cutting the tissue pieces at the interface by controlling characteristics of the electrical power impulse.   
     
     
         2 . A method as defined in  claim 1 , wherein the electrical power impulse has a time duration of no greater than 2.0 seconds. 
     
     
         3 . A method as defined in  claim 1 , wherein the electrical power impulse has a time duration of approximately 1.5 seconds. 
     
     
         4 . A method as defined in  claim 1 , wherein the electrical power impulse has a time duration in the range of 1.5 seconds to 2.0 seconds. 
     
     
         5 . A method as defined in  claim 4 , further comprising:
 releasing compression of the interface immediately after termination of the electrical power impulse.   
     
     
         6 . A method as defined in  claim 1 , further comprising:
 elevating the temperature of the thermal energy applied at the compressed interface at a rate of between 150° C. per second to 500° C. per second or greater from energy contained in the electrical power impulse.   
     
     
         7 . A method as defined in  claim 1 , further comprising:
 producing an energy density in the range of 388 W/cm2 to 465 W/cm2 of area of the compressed interface from the electrical power impulse.   
     
     
         8 . A method as defined in  claim 1 , further comprising:
 producing an energy density of at least 233 W/cm2 of area of the compressed interface from the electrical power impulse.   
     
     
         9 . A method as defined in  claim 1 , further comprising:
 producing an energy density of at least 388 W/cm2 of area of the compressed interface from the electrical power impulse.   
     
     
         10 . A method as defined in  claim 1 , further comprising:
 cutting the fused tissue pieces in a curved linear path through the interface.   
     
     
         11 . A method as defined in  claim 1 , further comprising:
 compressing the tissue pieces together at the interface to achieve essentially a zero thickness of the heated and compressed tissue pieces along the linear path.   
     
     
         12 . A method as defined in  claim 1 , further comprising:
 producing pressure of the least 0.88 N/mm2 over the effective area of the fused interface while compressing the tissue pieces.   
     
     
         13 . A method as defined in  claim 1 , further comprising:
 compressing the tissue pieces at the interface by contacting the tissue pieces on opposite sides of the interface by working surfaces of jaws;   applying the thermal energy to heat the jaws; and   transferring thermal energy from the working surfaces to the compressed interface of the tissue pieces.   
     
     
         14 . A method as defined in  claim 13 , further comprising:
 forming electrical power impulse from direct current; and   applying the direct current of the electrical power impulse to heat each jaw.   
     
     
         15 . A method as defined in  claim 13 , wherein each working surface is formed of ceramic material and each working surface has a smoothness defined by an Ra of 0.40 microns or less. 
     
     
         16 . A method as defined in  claim 13 , wherein each of the working surfaces extends in a dimension, and further comprising:
 releasing compression of the interface after fusion and simultaneous cutting by moving the working surfaces away from the fused and cut interface with the dimensions of each working surface extending parallel to one another.   
     
     
         17 . A method as defined in  claim 13 , further comprising:
 delivering an electrical power impulse to a heating element within each jaw; and   separately regulating characteristics the electrical power impulse delivered to the heating element within each jaw to regulate the temperature of thermal energy applied by the working surface from each jaw separately.   
     
     
         18 . A method as defined in  claim 1 , further comprising:
 releasing compression of the interface immediately after fusion without inducing shear forces on the fused interface.   
     
     
         19 . A method as defined in  claim 1 , further comprising:
 creating strength between the fused tissue pieces at the interface from the fusion which is less than the inherent strength of each tissue piece at the fused interface to allow separation of the tissue pieces at the interface before breaching the tissue pieces at or adjoining the fused interface.   
     
     
         20 . A method as defined in  claim 1 , wherein pieces of tissue are apposite walls of a vessel, and the compressed tissue thickness sufficient to fuse the opposite walls of the blood vessel is 0.05 mm to 0.10 mm. 
     
     
         21 . A method as defined in  claim 20 , wherein the vessel has a diameter of up to 8 mm.