Thermal cautery devices with improved heating profiles

Abstract

Thermal cautery and thermal ligating devices improved by the addition of a thermally conductive plate proximate the resistive heating element used in those devices.

1 . A medical device comprising: 
 a laparoscopic grasper characterized by a first arm and a second arm, each of said arms having a proximal end and distal end, each of said arms being rotatably relative to the other about a point near the distal end of the grasper, said arms being adapted to be inserted into the body and to be rotatably opened and closed upon each other within the body, said first arm having a first gripping face disposed on the distal end thereof, said second arm having second gripping face disposed on the distal end thereof, said gripping faces defining surfaces generally perpendicular to a plane defined by the grasping arms, said surfaces being movable into apposition with each other upon closing of the grasper;    a first layer of resilient material disposed on the gripping face of the first arm;    a second layer of resilient material disposed on the gripping face of the second arm;    a wire disposed between of the first and second layers of resilient material so as to be trapped between the gripping faces of the first and second arm upon closing of the graspers and    a thermally conductive and electrically insulative plate disposed between the wire and the gripping face of the first arm.    
   
   
       2 . The device of  claim 1  wherein the plate is 0.065 to 0.100 inches wide.  
   
   
       3 . The device of  claim 1  further comprising an electrically insulative layer disposed between the wire and the plate.  
   
   
       4 . The device of  claim 3  wherein the electrically insulative layer comprises a coating on the thermally conductive plate.  
   
   
       5 . The device of  claim 3  wherein the thermally conductive layer comprises a metal and the electrically insulative layer comprises an oxide of the metal.  
   
   
       6 . The device of  claim 3  wherein the thermally conductive plate and electrically insulative layer comprise an anodized metal plate.  
   
   
       7 . The device of  claim 1  wherein the thermally conductive plate comprises a thermally conductivity ceramic.  
   
   
       8 . The device of  claim 1  wherein the thermally conductive plate comprises a plastic incorporating a high thermal conductivity metal or ceramic.  
   
   
       9 . The device of  claim 1  wherein the thermally conductive plate is arcuate relative to the transverse cross section of the grasping arms.  
   
   
       10 . The device of  claim 1 , wherein the grasping face of the first grasping arm is substantially convex and the plate is substantially semi-cylindrical.  
   
   
       11 . The device of  claim 1 , wherein the first grasping arm is substantially cylindrical and the plate is substantially semi-cylindrical.  
   
   
       12 . The device of  claim 1  further comprising: 
 a sleeve covering the distal end of the first grasping arm, thereby forming a thermally insulative surface on the grasping face of the first grasping arm.    
   
   
       13 . The device of  claim 1  further comprising: 
 a resilient sleeve covering the distal end of the second grasping arm, thereby forming a resilient surface on the grasping face of the second grasping arm.    
   
   
       14 . The device of  claim 1  further comprising: 
 a sleeve covering the distal end of the first grasping arm, thereby forming a surface on the grasping face of the first grasping arm, between the wire and the grasping face of the arm, and    a resilient sleeve covering the distal end of the second grasping arm, thereby forming the resilient surface on the grasping face of the second grasping arm.