Apparatus and Method for Rapid Reliable Electrothermal Tissue Fusion

Abstract

A method of electrothermally fusing together pieces of tissue at an interface includes: compressing the tissue pieces together at the interface sufficiently for fusing the tissue pieces together 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 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 regulating the temperature of the thermal energy applied at the interface in a range of 150° C. to 200° C. while fusing the tissue pieces 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, comprising:
 compressing the tissue pieces together at the interface sufficiently for fusing the tissue pieces together 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 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   regulating the temperature of the thermal energy applied at the interface in a range of 150° C. to 200° C. while fusing the tissue pieces 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 0.5 seconds. 
     
     
         4 . A method as defined in  claim 1 , wherein the electrical power impulse has a time duration in the range of 0.5 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 from energy contained in the electrical power impulse.   
     
     
         7 . A method as defined in  claim 1 , further comprising:
 producing an energy density of at least 155 W/cm 2  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/cm 2  of area of the compressed interface from the electrical power impulse.   
     
     
         9 . A method as defined in  claim 1 , further comprising:
 compressing the tissue pieces at the interface to a thickness of 0.05 mm to 0.10 during fusing the tissue pieces.   
     
     
         10 . A method as defined in  claim 9 , further comprising:
 compressing the tissue pieces together at the interface with a force of 110 N to 150 N.   
     
     
         11 . A method as defined in  claim 9 , further comprising:
 producing pressure in the range of 0.88 N/mm 2  to 1.2 N/mm 2  over the effective area of the fused interface while compressing the tissue pieces.   
     
     
         12 . 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.   
     
     
         13 . A method as defined in  claim 12 , further comprising:
 forming electrical power impulse from direct current; and   applying the direct current of the electrical power impulse to a heat each jaw.   
     
     
         14 . A method as defined in  claim 12 , 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. 
     
     
         15 . A method as defined in  claim 12 , wherein each of the working surfaces extends in a dimension, and further comprising:
 releasing compression of the interface after fusion by moving the working surfaces away from the fused interface with the dimensions of each working surface extending parallel to one another.   
     
     
         16 . A method as defined in  claim 12 , further comprising:
 delivering an electrical power impulse to the 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.   
     
     
         17 . 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.   
     
     
         18 . A method as defined in  claim 1 , further comprising:
 creating strength between the 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 interface.   
     
     
         19 . 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. 
     
     
         20 . A method as defined in claim  46 , wherein the vessel has a diameter of up to 8 mm.