Electrosurgical Apparatus and Methods for Treatment and Removal of Tissue

Abstract

Apparatus and methods for ablating, severing, cutting, shrinking, coagulating, or otherwise modifying a target tissue to be treated. In a method for treating a target tissue, an active electrode of an electrosurgical probe is positioned in at least close proximity to the target tissue in the presence of an electrically conductive fluid. A high frequency voltage is then applied between the active electrode and a return electrode, wherein, the high frequency voltage is sufficient to volumetrically remove (ablate), sever, or modify at least a portion of the target tissue. The probe comprises a multi-lumen shaft having a plurality of internal lumens, and a return electrode coil oriented substantially parallel to the shaft distal end. The active electrode may be in the form of a metal disc, a hook, or an active electrode coil. In the latter embodiment, the active electrode coil is typically arranged substantially orthogonal to the return electrode coil. Methods of making an active electrode coil, a return electrode coil, and an electrosurgical probe are also disclosed.

1 - 37 . (canceled)  
   
   
       38 . An electrosurgical probe, comprising: 
 a shaft comprising a multi-lumen extrusion, the shaft having a shaft proximal end portion and a shaft distal end portion;    an electrode assembly at the shaft distal end portion; and    a connection block adapted for coupling the electrode assembly to an electrosurgical generator.    
   
   
       39 . The probe of  claim 38 , wherein the multi-lumen extrusion comprises a plastic tube.  
   
   
       40 . The probe of  claim 38 , wherein the multi-lumen extrusion comprises a polyurethane elastomer.  
   
   
       41 . The probe of  claim 40 , wherein the polyurethane elastomer is polyether based and includes from about 0.5% to 4% of carbon black.  
   
   
       42 . The probe of  claim 38 , wherein the multi-lumen extrusion includes a plurality of interior lumens.  
   
   
       43 . The probe of  claim 38 , wherein the multi-lumen extrusion includes first, second, third, and fourth lumens.  
   
   
       44 . The probe of  claim 43 , wherein the electrode assembly includes a return electrode and an active electrode, and the first and second lumens accommodate the return electrode and the active electrode, respectively.  
   
   
       45 . The probe of  claim 43 , wherein the third lumen comprises a fluid delivery lumen.  
   
   
       46 . The probe of  claim 45 , wherein the third lumen terminates distally in a fluid delivery port.  
   
   
       47 . The probe of  claim 43 , wherein the fourth lumen comprises an aspiration lumen.  
   
   
       48 . The probe of  claim 47 , wherein the fourth lumen terminates distally in an aspiration port.  
   
   
       49 . The probe of  claim 42 , wherein each of the plurality of interior lumens has a diameter in the range of from about 0.015 inch to 0.100 inch.  
   
   
       50 . The probe of  claim 38 , wherein the electrode assembly comprises an active electrode, the active electrode including an active electrode filament and an active electrode head.  
   
   
       51 . The probe of  claim 50 , wherein the active electrode head comprises a hook.  
   
   
       52 . The probe of  claim 50 , wherein the active electrode head comprises an active electrode coil having about 1 turn.  
   
   
       53 . The probe of  claim 52 , wherein the active electrode head includes a dividing portion, the dividing portion spanning the active electrode coil to form a plurality of voids within the active electrode coil.  
   
   
       54 . The probe of  claim 38 , further comprising a handle affixed to the shaft proximal end portion, the handle housing the connection block.  
   
   
       55 . The probe of  claim 52 , wherein the active electrode comprises a metal wire selected from the group consisting of molybdenum, platinum, tungsten, palladium, iridium, titanium, and their alloys.  
   
   
       56 . The probe of  claim 52 , wherein an edge of the active electrode coil is offset from the longitudinal axis of the active electrode filament by a minimum distance in the range of from about 0.008 to about 0.016 inches.  
   
   
       57 . The probe of  claim 52 , wherein the active electrode coil has a diameter in the range of from about 0.050 to 0.150 inches.  
   
   
       58 . The probe of  claim 38 , wherein the electrode assembly further comprises a return electrode, the return electrode including a return electrode filament and a return electrode head.  
   
   
       59 . The probe of  claim 58 , wherein the return electrode head comprises a return electrode coil having from about 3 to 10 turns.  
   
   
       60 . The probe of  claim 58 , wherein the probe further comprises a connection block adapted for coupling the probe to a high frequency power supply, and the return electrode filament distal end is coupled directly to the connection block.  
   
   
       61 . An electrosurgical probe, comprising: 
 a shaft having a shaft proximal end portion and a shaft distal end portion; and    an electrode assembly at the shaft distal end portion, the electrode assembly comprising an active electrode and a return electrode, the return electrode disposed within a lumen of the shaft, the return electrode in the form of a return electrode coil, the return electrode coil having an internal void, and the return electrode distal terminus arranged within the internal void.    
   
   
       62 . The probe of  claim 61 , wherein the return electrode coil has from about 3 to 10 turns.  
   
   
       63 . The probe of  claim 61 , wherein the internal void is substantially cylindrical.  
   
   
       64 . The probe of  claim 61 , wherein the return electrode distal terminus is located at the proximal end of the internal void.  
   
   
       65 . The probe of  claim 61 , wherein the shaft comprises a multi-lumen tube having a plurality of lumens therein.  
   
   
       66 . The probe of  claim 65 , wherein the multi-lumen tube is an extrusion product.  
   
   
       67 . The probe of  claim 66 , wherein the multi-lumen tube comprises a polyether based polyurethane elastomer.  
   
   
       68 . The probe of  claim 61 , wherein the active electrode comprises an active electrode coil having from about 0.5 to 1.5 turns.  
   
   
       69 . The probe of  claim 68 , wherein the active electrode further comprises a dividing portion arranged within the active electrode coil.  
   
   
       70 . The probe of  claim 69 , wherein the dividing portion defines two voids within the active electrode coil.  
   
   
       71 . The probe of  claim 68 , wherein the active electrode coil is flattened.  
   
   
       72 . The probe of  claim 71 , wherein the active electrode coil is offset from the longitudinal axis of the shaft distal end portion.  
   
   
       73 . An electrosurgical probe, comprising: 
 a shaft having a shaft proximal end portion and a shaft distal end portion; and    an electrode assembly at the shaft distal end portion, the electrode assembly comprising an active electrode and a return electrode, the active electrode comprising a metal disc.    
   
   
       74 . The probe of  claim 73 , wherein the active electrode head has a sharp edge.  
   
   
       75 . The probe of  claim 73 , further comprising a handle housing a connection block, wherein the return electrode includes a distal end portion and a proximal end portion, the proximal end portion inserted directly in the connection block.  
   
   
       76 . An electrosurgical probe, comprising: 
 a shaft having a shaft proximal end portion and a shaft distal end portion;    a return electrode comprising a return electrode coil; and    an active electrode having a distal end portion and a proximal end portion, the distal end portion comprising an active electrode coil having from about 0.5 to 1.5 turns, the active electrode coil oriented substantially orthogonal to the return electrode coil.    
   
   
       77 . The electrosurgical probe of  claim 76 , wherein the active electrode coil includes a dividing portion, the dividing portion at least partially spanning an internal void within the active electrode coil.  
   
   
       78 . The probe of  claim 76 , wherein the active electrode coil is substantially circular in cross-section, the active electrode including a dividing portion, and the dividing portion bisecting the coil at an angle of about 45 degrees with respect to the shaft distal end portion.  
   
   
       79 . The probe of  claim 76 , wherein the active electrode coil is flattened.  
   
   
       80 . The electrosurgical probe of  claim 76 , wherein the active electrode coil is substantially disc-shaped.  
   
   
       81 . The probe of  claim 76 , wherein the return electrode coil comprises from about 3 to 10 turns.  
   
   
       82 . The electrosurgical probe of  claim 76 , wherein the active electrode lies within the return electrode coil.