Tissue ablation cannula and elecgtrode assembly that can be selectively operated with one or more active tips

Abstract

An assembly ( 32 ) for use as part of an electrosurgical tool system ( 30 ). The assembly includes a cannula ( 42 ) and an electrode ( 66 ). The cannula is formed with a bend ( 54 ) proximal to the distal section. The electrode has a bent section ( 80 ) formed from a flexible shape memory material. The electrode can be inserted into the cannula so that a distal section of the electrode seats in the distal section of the cannula. In this configuration, the assembly has a single active tip, the distal section of the cannula. Alternatively, the electrode can be oriented so that when the electrode is inserted in the cannula the distal section of the electrode extends out of a side opening ( 58 ) of the cannula. In this configuration, the assembly has two active tips, the distal sections of both the cannula and the electrode.

What is claimed is: 
     
         1 . A cannula and electrode assembly including:
 a cannula having a cannula body having: opposed proximal and distal ends; a distal section that is electrically conductive, the distal section defining the distal end of the cannula body; a bend proximal to the cannula distal section; a lumen that extends distally and longitudinally from the proximal end of the cannula body; and a side opening that extends through a portion of the cannula body that defines an outer portion of the bend, the side opening opening into the cannula body lumen; and   an electrode adapted for connection to a cable that connects the electrode to a control console, the electrode having an electrode body dimensioned to seat in the lumen of said cannula body, said electrode body having: a distal section formed from electrically conductive material that is electrically connected to a conductor internal to the cable and a section proximal to the distal section formed from elastic material, the section formed from elastic material being located so that, when the electrode body is inserted in the cannula lumen, the section is within the section of the lumen defined by the bend in said cannula body and the bend is shaped so that, depending on the rotational orientation of the electrode body relative to the cannula body, when the electrode body is inserted in the cannula body the electrode body distal section either seats in the lumen portion within the cannula body distal section or extends out of the cannula body side opening.   
     
     
         2 . The cannula and electrode assembly of  claim 1 , wherein said cannula and said electrode are formed with complementary indicia that are arranged to provide an indication of the rotational orientation of the electrode body relative to the cannula body. 
     
     
         3 . The cannula and electrode assembly of  claim 2 , wherein:
 said cannula has a hub and said cannula indicia is disposed on the cannula hub; and   the proximal end of said cannula body is mounted to the hub and the cannula body extends distally from said hub.   
     
     
         4 . The cannula and electrode assembly of  claim 2 , wherein:
 said electrode has a hub, said hub being the component of the electrode to which the cable is connected;   said electrode body extends from said hub; and   said electrode indicia are disposed on the electrode hub.   
     
     
         5 . The cannula and electrode assembly of  claim 1 , wherein said cannula body is formed from a single piece of material. 
     
     
         6 . The cannula and electrode assembly of  claim 1 , wherein said electrode body is formed from a single piece of material. 
     
     
         7 . The cannula and electrode assembly of  claim 1 , wherein the section of said electrode formed from elastic material is formed from a nickel titanium alloy. 
     
     
         8 . The cannula and electrode assembly of  claim 1 , wherein said electrode body is in the form of a tube having a closed distal end. 
     
     
         9 . The cannula and electrode assembly of  claim 1 , wherein an electrically insulating sleeve is disposed over the cannula body, said sleeve extending proximally from a location spaced proximally to the distal end of the cannula body. 
     
     
         10 . The cannula and electrode assembly of  claim 1 , further including a temperature sensor disposed in said electrode body. 
     
     
         11 . The cannula and electrode assembly of  claim 10 , wherein said temperature sensor is a thermocouple. 
     
     
         12 . The cannula and electrode assembly of  claim 1 , wherein said assembly is structured as a monopolar cannula and electrode assembly. 
     
     
         13 . The cannula and electrode assembly of  claim 1 , wherein:
 said cannula has a hub; and   the proximal end of said cannula body is mounted to the hub and the cannula body extends distally from said hub.   
     
     
         14 . The cannula and electrode assembly of  claim 1 , wherein:
 said electrode has a hub, said hub being the component of said electrode to which the cable is connected; and   said electrode body extends from said hub.   
     
     
         15 . The cannula and electrode assembly of  claim 1 , wherein said electrode further includes a sleeve formed from insulating material that extends at least partially over said electrode body 
     
     
         16 . The cannula and electrode assembly of  claim 1 , wherein the radius of curvature of the bend of said cannula is between 40 and 60 mm. 
     
     
         17 . A cannula and electrode assembly, said assembly including:
 an electrode configured for connection to a cable, said electrode including:
 a hub formed electrically insulting material, said hub including opposed surfaces thereof indicia, the indicia on the opposed surfaces being different from each other; and 
 a body, said body having: a proximal section that extends distally forward from said electrode hub; a distal section located forward of the proximal section, the distal section being formed from electrically conductive material and electrically connected to a conductor internal to the cable, the distal section defining an end of the body; and a bend located between the proximal and distal sections, so that as a result of the presence of the bend the proximal and distal sections of said electrode body are axially angularly offset from each other; and 
   a cannula, said cannula including:
 a hub formed from electrically insulting material and being formed with a bore for receiving said body of said electrode, said cannula having a indicia; and 
 a body, said body shaped to have: a proximal section that extends from said cannula hub; a distal section located forward of the proximal section, a bend that is located between the proximal and distal sections so that, as a result of the presence of said cannula body, the proximal and distal sections of the cannula body are axially angularly offset from each other, a lumen that extends through the proximal section, the bend and distal section of said cannula body, the lumen dimensioned to receive said electrode body and side opening in an outer surface of the bend, said side opening opening into the lumen that extends through the cannula body and wherein the bend and the side opening are formed in the cannula body so that: when the electrode body is inserted in first rotational orientation within the cannula body to place a first one of the indicia on said electrode hub is registration with the indicia of said cannula hub, the distal section of the electrode body seats in the portion of the cannula lumen disposed in the distal section of said cannula body; and, when the electrode body is inserted in a second rotational orientation to place a second one of the indicia of the electrode hub in registration with the indicia of the cannula hub, the bend of the electrode body causes the distal section of the electrode body to extend out through the side opening in said cannula body. 
   
     
     
         18 . The cannula and electrode assembly of  claim 17 , wherein said electrode body is formed from a single piece of material. 
     
     
         19 . The cannula and electrode assembly of  claim 17 , wherein said assembly is structured as a monopolar cannula and electrode assembly. 
     
     
         20 . The cannula and electrode assembly of  claim 1 , wherein the radius of curvature of the bend of said cannula is between 40 and 60 mm.