Over-the-wire high frequency electrode

Abstract

A device for ablation of target tissue in the living body such as a tumor comprises an elongate member that can be guided over a guide element into the target tissue. The elongated element has an electrode at its distal portion. The electrode is configured to be energized with high frequency energy to ablate the target tissue. The elongate member has a guide hole through it and is configured to pass over a guide element that has perforated and penetrated the skin and tissue along a tract to the target volume. The elongate member can be made of a rigid metal tube or a flexible plastic tube. The elongate member can include a cooling channel within it so that cooling fluid can be circulated within the elongate member to cool the electrode, and thus to enlarge the ablation volume at the target tissue.

What is claimed is:  
     
         1 . A device for ablating tissue in the living body comprising: 
 a guide element; and    an elongate member defining a longitudinal passage having a distal opening and a proximal opening dimensioned to pass along and over the guide element directed into the tissue, the elongated member including an electrode disposed at a distal portion of the elongate member and configured to be energized with high frequency energy to ablate tissue.    
     
     
         2 . The device of  claim 1  wherein the elongate member comprises a blunt distal tip.  
     
     
         3 . The device of  claim 2 , wherein the blunt distal tip is a conical tip  
     
     
         4 . The device of  claim 1  wherein: 
 the device further comprises a fluid inlet port and a fluid outlet port; and  
 the elongate member further defines a fluid channel in fluid communication with the fluid inlet port and the fluid outlet port and in thermal communication with the electrode.  
 
     
     
         5 . The device of  claim 4 , wherein the fluid output port is at a proximal portion of the elongate member.  
     
     
         6 . The device of  claim 2  wherein: 
 the elongate member is rigid; and  
 the blunt distal tip converges smoothly with the distal opening.  
 
     
     
         7 . The device of  claim 6  wherein: 
 the blunt distal tip comprises a rounded contour surrounding the distal opening.  
 
     
     
         8 . The device of  claim 6  wherein the blunt distal tip comprises a tapered contour converging with the distal opening.  
     
     
         9 . The device of  claim 7  wherein the elongate member is flexible.  
     
     
         10 . The device of  claim 9  wherein the electrode includes a tapered contour converging with the distal opening.  
     
     
         11 . The device of  claim 2  wherein the elongate member is flexible.  
     
     
         12 . The device of  claim 11  wherein the electrode is a ring.  
     
     
         13 . The device of  claim 1  wherein 
 the elongate tubular member is rigid, a lumen is dimensioned to pass along and over the guide element directed into the tissue and the distal portion of the tubular member has a blunt distal tip; and further comprising:  
 a fluid channel within the tubular member, the fluid channel in fluid communication with a fluid input port and a fluid output port and in thermal communication with the electrode.  
 
     
     
         14 . The device of  claim 13 , wherein the blunt distal tip is a conical tip.  
     
     
         15 . The device of  claim 13 , wherein the blunt distal tip is fluidly sealed to the tubular member and an inner metal tube.  
     
     
         16 . The device of  claim 13 , wherein: 
 the tubular member comprises a plastic tube; and    the electrode comprises a metal element.    
     
     
         17 . The device of  claim 13 , wherein the fluid output port is at a proximal portion of the elongate member.  
     
     
         18 . The device of  claim 13 , wherein the fluid output port is at a proximal portion of the elongate member.  
     
     
         19 . The device of  claim 1  wherein 
 the elongate tubular member is flexible, a lumen is dimensioned to pass along and over the guide element directed into the tissue, and the distal portion of the tubular member has a blunt distal tip; and further comprising:  
 a fluid channel within the tubular member, the fluid channel in fluid communication with a fluid input port and a fluid output port and in thermal communication with the electrode.  
 
     
     
         20 . The device of  claim 19 , wherein the blunt distal tip is a conical tip.  
     
     
         21 . The device of  claim 19  wherein the electrode includes a tapered contour converging with the distal opening.  
     
     
         22 . The device of  claim 21  wherein the electrode is a ring.  
     
     
         23 . A system for ablation of tissue in the living body comprising: 
 a guide element; and    an ablation system including:    an elongate member defining a longitudinal channel having a distal opening and proximal opening, the elongate member being dimensioned to slide along and over the guide element directed into the tissue; and    an electrode at a distal portion of the elongate member and configured to be energized with high frequency energy to ablate the tissue.    
     
     
         24 . The system of  claim 23  wherein the guide element comprises a flexible guide wire.  
     
     
         25 . The system of  claim 23  wherein the guide element comprises a rigid stylet wire.  
     
     
         26 . The system of  claim 23  wherein the guide element comprises an anchor that extends laterally from a distal guide portion of the guide element, the anchor configured to anchor the distal guide portion near a target.  
     
     
         27 . The system of  claim 23  wherein the guide element comprises a tube containing a movable member.  
     
     
         28 . The system of  claim 27  wherein the movable member is a tube.  
     
     
         29 . The system of  claim 27  wherein the movable member is an anchor.  
     
     
         30 . The system of  claim 23  wherein the ablation system further comprises: 
 a high frequency generator; and  
 electrical conductors connecting the high frequency generator to the electrode.  
 
     
     
         31 . The system of  claim 23  wherein: 
 the elongate member defines a fluid channel in fluid communication with a fluid input and a fluid outlet and in thermal communication with the electrode; and  
 the ablation system further comprises a coolant supply connected to the fluid input.  
 
     
     
         32 . The system of  claim 23  wherein the ablation system further comprises a fluid agent injector.  
     
     
         33 . A method for thermal ablation of a target volume comprising: 
 perforating and penetrating a living body using a guide element to establish a tract through the body to the target volume;    sliding an electrode along and over the guide element directed into the body to position the electrode near the target volume, the electrode including an elongate member defining a longitudinal passage dimensioned to pass along the guide wire, a conductive surface at a distal portion of the elongate member, and an electrical connection between the conductive surface and a proximal portion of the elongate member;    connecting the electrical connection to a high frequency generator;    supplying high frequency energy from the generator through the electrode to the target volume to thermally ablate the target volume.    
     
     
         34 . The method of  claim 33  further comprising cooling the electrode while supplying high frequency energy to change a spatial distribution of heat near the electrode, cooling including connecting a source of a coolant to a fluid input and causing a coolant to flow in a fluid channel in the elongate member, the fluid channel being in fluid communication with the fluid input and a fluid output and in thermal communication with the electrode.  
     
     
         35 . The method of  claim 33  wherein positioning comprises deploying an anchor from the guide wire to anchor the guide wire in the tract.  
     
     
         36 . The method of  claim 33  further including dilating the tissue along the tract after positioning the guide wire by passing a dilating element over the guide wire to expand the tissue along the tract prior to sliding the electrode along the guide wire.  
     
     
         37 . The method of  claim 33  further comprising introducing a fluid agent through the guide element.  
     
     
         38 . The method of  claim 33  further comprising introducing a chemotherapeutic agent through the guide element prior to or while supplying high frequency energy.