Shapeable electrosurgical scalpel

Abstract

The invention is directed to an electrosurgical device having a shapeable elongate cutting electrode having a free distal end with an exposed length of at least 0.5 inch and secured by its proximal end to the distal end of a handle. The electrosurgical device is designed for use with a high frequency electrosurgical generator which has an output at a frequency of between about 1 MHz and about 10 MHz, preferably about 3 to about 8 MHz. Preferably, the output has an essentially sinusoidal waveform with little harmonic distortion. The methods provide for the enhanced cutting of a variety of tissue including muscular, connective, glandular and fatty tissue. The device is particularly suitable in performing a breast biopsy.

1 . An electrosurgical cutting device comprising:
 a handle which has a proximal end and a distal end;   an elongated cutting electrode which has a proximal end secured to the distal end of the handle, which has free distal end and which has an exposed active surface over a length of at least 0.5 inch.   
   
   
       2 - 70 . (canceled) 
   
   
       71 . An electrosurgical tissue cutting system, comprising:
 a. an electrosurgical tissue cutting device, comprising:
 i) a housing which has a proximal end, a distal end, a distal portion extending proximally from the distal end, an electrically insulating and electrode supporting bushing fixed within the distal portion suitable for high frequency electrical contact, and an inner lumen extending within the housing and through the insulating bushing; 
 ii) an elongated electrosurgical tissue cutting electrode assembly which is slidably disposed in part within the inner lumen of the housing and the insulating bushing, which has an electrical power transmission member with a distal portion passing through the proximal end of the housing, which has an elongated electrosurgical tissue cutting electrode with proximal and distal ends and a manually shapeable, uninsulated distal portion extending through the inner lumen of the insulating bushing and out of the housing and in contact with and supported by the insulating bushing and which has a connector secured to the distal portion of the electrical power transmission member extending into the housing lumen and the proximal end of the electrosurgical electrode to effect an electrical connection therebetween. 
   b. an electrosurgical RF power source;   c. a transformer in electrical conducting relationship with the RF power source;   d. a first electrical conductor configured for RF transmission in electrical conducing relationship between the transformer and the electrosurgical device;   e. a return electrode configured to be electrically connected to the patient; and   f. an a second electrical conductor configured for electrical conduction between the return electrode and the transformer.   
   
   
       72 . The electrosurgical system of  claim 71  wherein the electrosurgical device has an axial translation member configured to slidably adjust the position of the electrosurgical tissue cutting electrode assembly within the inner lumen of the housing to adjust the length of the bare, uninsulated distal portion of the elongated electrosurgical tissue cutting electrode that can be extended out of the insulated ceramic bushing. 
   
   
       73 . The electrosurgical tissue cutting system of  claim 71  wherein the electrosurgical tissue cutting electrode has a bare, uninsulated distal portion having a length of about 0.75 inches to about 4 inches. 
   
   
       74 . The electrosurgical tissue cutting system of  claim 71  wherein the electrosurgical tissue cutting electrode has a bare, uninsulated distal portion having a length of about 1.2 inch to about 2.5 inches. 
   
   
       75 . The electrosurgical tissue cutting system of  claim 71  wherein the bare, uninsulated distal portion of the electrosurgical tissue cutting electrode has a transverse dimension over a substantial length thereof from about 0.007 to about 0.03 inch. 
   
   
       76 . The electrosurgical tissue cutting system of  claim 71  wherein the bare, uninsulated distal portion of the electrosurgical tissue cutting electrode has a transverse dimension over a substantial length thereof from about 0.01 to about 0.02 inch. 
   
   
       77 . The electrosurgical tissue cutting system of  claim 71  wherein the distal cutting portion of the electrosurgical tissue cutting electrode tapers distally to a reduced transverse dimension. 
   
   
       78 . The electrosurgical tissue cutting system of  claim 77  wherein the bare, uninsulated distal cutting portion of the electrosurgical tissue cutting electrode tapers from a transverse dimension of at least 0.012 inch in a proximal portion thereof to a transverse dimension of less than about 0.012 inch in a distal portion of the tissue cutting electrode. 
   
   
       79 . The electrosurgical tissue cutting system of  claim 77  wherein the electrosurgical tissue cutting electrode tapers distally from a transverse dimension of between about 0.012 and about 0.018 inch at a proximal portion of the cutting electrode to a transverse dimension of between about 0.004 to about 0.01 inch at the distal portion of the tissue cutting electrode. 
   
   
       80 . The electrosurgical tissue cutting system of  claim 71  wherein the electrosurgical tissue cutting electrode is formed at least in part of a metallic material selected from the group consisting of tungsten, tungsten alloys, stainless steel, and combinations thereof. 
   
   
       81 . The electrosurgical tissue cutting system of  claim 80  wherein the metallic material is a tungsten alloy containing rhenium. 
   
   
       82 . The electrosurgical tissue cutting system of  claim 81  wherein the tungsten alloy contains from about 3% to about 25% rhenium. 
   
   
       83 . The electrosurgical tissue cutting system of  claim 80  wherein the metallic material is a stainless steel. 
   
   
       84 . The electrosurgical system of  claim 71  wherein the electrosurgical device has an axial translation member configured to slidably adjust the position of the electrosurgical tissue cutting electrode assembly within the inner lumen of the housing to adjust the length of the bare, uninsulated distal portion of the elongated electrosurgical tissue cutting electrode that can be extended out of the insulated bushing. 
   
   
       85 . The electrosurgical tissue cutting system of  claim 84  wherein the axial translation member of the handle further comprises a finger operated slide. 
   
   
       86 . The electrosurgical tissue cutting system of  claim 85  wherein the finger operated slide of the axial translation member is configured to extend through a slot provided in the handle to an exterior location. 
   
   
       87 . The electrosurgical tissue cutting system of  claim 71  wherein the insulating bushing is formed at least in part of a ceramic material. 
   
   
       88 . The electrosurgical tissue cutting system of  claim 71  wherein the insulating bushing is formed at least in part of a mica glass. 
   
   
       89 . The electrosurgical tissue cutting system of  claim 71  wherein the insulating bushing in the distal end of the housing has a nose cone which extends out of the housing. 
   
   
       90 . The electrosurgical tissue cutting system of  claim 71  wherein electrosurgical RF power source is configured to have a frequency output of between about 1 to about 10 MHz. 
   
   
       91 . The electrosurgical tissue cutting system of  claim 90  wherein the RF power source is configured to produce an electrical output having an essentially sinusoidal waveform. 
   
   
       92 . The electrosurgical tissue cutting system of  claim 91 , wherein the sinusoidal waveform has a total harmonic distortion less than about 5%. 
   
   
       93 . The electrosurgical tissue cutting system of  claim 90 , wherein the RF power source has a frequency of about 3 MHz to about 8 MHz. 
   
   
       94 . The electrosurgical tissue cutting system of  claim 71  including a controller configured to control the electrical current passed to the elongated electrosurgical tissue cutting electrode based upon a first voltage setpoint at the initiation of tissue cutting and on a second voltage setpoint after the initiation of tissue cutting. 
   
   
       95 . The electrosurgical tissue cutting system of claim  claim 94  wherein the first voltage setpoint is between about 450 Vrms to about 550 Vrms. 
   
   
       96 . The electrosurgical tissue cutting system of  claim 94  wherein the second voltage setpoint is between about 550 Vrms to about 650 Vrms. 
   
   
       97 . The electrosurgical tissue cutting system of  claim 71  wherein a flexible coaxial cable is secured to the proximal end of the handle which is electrically connected to the cutting electrode, which has an inner electrical conductor extending the length thereof unsupported, which has an outer tubular jacket disposed about and space radially from the inner electrical conductor and formed of an inner polymeric layer, a shielding layer and an outer polymer layer and which has a gas filled interior between the jacket and the electrical conductor.