Methods and devices for radiofrequency electrosurgery

Abstract

An electrically activated surgical device includes a probe body, an active element and a structure for selectively electrically insulating and/or physically isolating the active element from the patient's tissue when the device is in use. The probe body defines an outer surface, a proximal end, a distal end and a window defined within the outer surface near or at the distal end. The active element is electrically connected to a power source and is configured to selectively assume a non-deployed configuration and a variable deployed configuration in which the active element at least partially emerges from the window out of the probe body. The insulating structure selectively insulates the active element from the patient's tissue when the device is inserted therein. In operation, a physician inserts the probe into the tissue, insulates the active element from the tissue (either before, during or after insertion of the probe), energizes the insulated active element using for example, radiofrequency (RF) power from the power source, and only then exposes the energized active element to the tissue. By insulating the active element during the energizing thereof, little or no current applied to the active element is dissipated in the patient's tissue, thus decreasing the time required to energize the active element and enabling lower and safer power levels to be applied to the active element during the energizing thereof.

What is claimed is:  
     
         1 . An electrosurgical device, comprising: 
 a body, the body defining an outer surface, a proximal end, a distal end and a window defined within the outer surface;    an electrically insulating layer, and    an active element, the active element being adapted to electrically connect to a power source and configured to selectively assume a non-deployed configuration in which the insulating layer electrically insulates the active element from a patient's tissue when the device is in use and a variable deployed configuration in which the active element at least partially emerges from the window out of the body to make contact with the patient's tissue.    
     
     
         2 . The device of  claim 1 , wherein the active element includes one of a ribbon and wire, said one of ribbon and wire being adapted to selectively bow out of the window when transitioning from the non-deployed configuration to the deployed configuration.  
     
     
         3 . The device of  claim 1 , wherein the active element is configured to carry out at least one of tissue ablation, dissection, fulguration, cautery, desiccation, hyperthermia and hypothermia.  
     
     
         4 . The device of  claim 1 , wherein a thickness of the insulating layer is selected within a range of about 0.1 mm to about 5 mm.  
     
     
         5 . The device of  claim 1 , wherein the power source includes an RF power source.  
     
     
         6 . The device of  claim 1 , wherein the window is disposed one of near the distal end of the body and at the distal end thereof.  
     
     
         7 . The device of  claim 6 , wherein the active element is ring-shaped and includes a trailing tissue collection means attached thereto adapted to collect tissue cut by the ring-shaped active element.  
     
     
         8 . The device of  claim 6 , wherein the insulating layer includes an electrically insulating sliding door mounted within the body, the sliding door being configured to selectively cover at least a portion of the window.  
     
     
         9 . The device of  claim 8 , wherein the sliding door is configured to slide between a variable first position in which at least a portion of the active element is exposed to the patient's tissue through the window and a second position in which the sliding door electrically insulates the active element within the body from the patient's tissue.  
     
     
         10 . The device of  claim 6 , wherein the insulating layer includes a layer of air and wherein the window is configured to maintain the layer of air between the active element and the patient's tissue when the active element is in the non-deployed configuration.  
     
     
         11 . The device of  claim 1 , wherein the insulating layer includes an electrically insulating outer sleeve configured to selectively slide over the outer surface of the body, the outer sleeve being configured to at least partially cover the active element to electrically insulate the active element from the patient's tissue and uncover the active element to expose the active element to the patient's tissue.  
     
     
         12 . The device of  claim 1 , wherein the insulating layer further includes an electrically insulating sheath disposed around at least a portion of the device body, the insulating sheath defining a cutaway portion aligned with the window, the insulating sheath defining at least one raised portion configured to prevent the patient's tissue from prolapsing into the window when the active element is in its non-deployed configuration.  
     
     
         13 . The device of  claim 1 , wherein the insulating layer includes an insulating sleeve disposed at least partially around the active element, the insulating sleeve being configured to controllably slide over the active element to selectively electrically insulate the active element from the patient's tissue and expose the active element thereto when the device is in use.  
     
     
         14 . The device of  claim 1 , wherein the body is shaped as a non-coring needle.  
     
     
         15 . The device of  claim 1 , wherein the insulating layer includes a layer of air and wherein the device body defines at least one raised portion adjacent the window, the at least one raised portion maintaining the layer of air between the active element and the patient's tissue when the active element is in its non-deployed state.  
     
     
         16 . The device of  claim 1 , further including suction means for controllably removing fluids from an excision site in the patient's tissue.  
     
     
         17 . A method of treating tissue using a probe, the probe including an active element that is extendable out of and retractable back into a window defined in the probe, the active element being electrically connected to a power source, comprising the steps of: 
 inserting the probe into the tissue;    electrically insulating the active element from the tissue;    energizing the active element using power from the power source, and    exposing the energized active element to the tissue.    
     
     
         18 . The method of  claim 17 , wherein the power source is adapted to supply RF power to the active element.  
     
     
         19 . The method of  claim 18 , wherein the insulating step includes a step of maintaining an electrically insulating layer between the active element and the tissue.  
     
     
         20 . The method of  claim 17 , wherein the probe further includes an electrically insulating sliding door and wherein the insulating step includes a step of sliding the door across the window.  
     
     
         21 . The method of  claim 17 , further comprising the step of inducing hyperthermia and necrosis in the tissue exposed to the active element.  
     
     
         22 . The method of  claim 17 , further comprising the step of inducing hypothermia and necrosis in the tissue exposed to the active element.  
     
     
         23 . The method of  claim 17 , wherein the probe further includes an electrically insulating outer sleeve adapted to slide over an outer surface of the probe and wherein the insulating step includes a step of sliding the outer sleeve over the window.  
     
     
         24 . The method of  claim 17 , wherein the probe further includes an insulating sheath around at least a portion of the probe body, the insulating sheath including at least one raised portion adjacent the window and wherein the insulating step includes a step of maintaining the active element retracted within the window.  
     
     
         25 . The method of  claim 17 , wherein the insulating step includes a step of maintaining the active element retracted within the window.  
     
     
         26 . The method of  claim 17 , wherein the probe further includes an insulating sleeve adapted to slide over the active element and wherein the insulating step includes a step of sliding the insulating sleeve over the active element.  
     
     
         27 . The method of  claim 17 , wherein the insulating step includes a step of creating or maintaining a layer of air between the active element and the tissue.  
     
     
         28 . The method of  claim 17 , wherein the probe further includes an inflatable balloon disposed adjacent the window, and wherein the insulating step further includes a step of inflating the balloon to create a layer of air between the tissue and the active element.  
     
     
         29 . An electrosurgical device, comprising: 
 a device body, the body defining a proximal end and a distal end;    an active element coupled to the body, the active element being adapted to be controllably energized from a power source, and    means for selectively electrically insulating and exposing the active element from and to a patient's tissue when the device is in use.    
     
     
         30 . The device of  claim 29 , wherein the active element is configured to selectively assume a non-deployed configuration in which the active element is recessed within the body and a variable deployed configuration in which the active element at least partially emerges from the body.  
     
     
         31 . The device of  claim 29 , wherein the active element is configured to carry out at least one of tissue ablation, dissection, fulguration, cautery, desiccation, hyperthermia and hypothermia.  
     
     
         32 . The device of  claim 29 , wherein the active element is configured to be energized by an RF power source.  
     
     
         33 . The device of  claim 29 , wherein the device body defines a window disposed near the distal end of the body, the active element being configured to selectively retract into and extend from the window.  
     
     
         34 . The device of  claim 29 , wherein a window is defined within the body and wherein the insulating means includes an electrically insulating sliding door mounted within the body, the sliding door being configured to selectively cover at least a portion of the window.  
     
     
         35 . The device of  claim 34 , wherein the sliding door is configured to slide between a variable first position in which at least a portion of the active element is exposed through the window and a second position in which the sliding door electrically insulates the active element from the patient's tissue.  
     
     
         36 . The device of  claim 33  wherein the insulating means are integral with the window and wherein the window is configured to prevent tissue from prolapsing therein and making physical and/or electrical contact with the active element when the active element is in a non-deployed configuration.  
     
     
         37 . The device of  claim 29 , wherein the insulating means includes an electrically insulating outer sleeve configured to selectively slide over the outer surface of the body, the outer sleeve being configured to at least partially cover the active element and electrically insulate the active element from the patient's tissue when the device is in use and the active element is in a non-deployed configuration.  
     
     
         38 . The device of  claim 29 , wherein the insulating means includes an electrically insulating sleeve disposed at least partially around the active element, the insulating sleeve being configured to controllably slide over the active element to selectively electrically insulate the active element from the patient's tissue and expose the active element thereto when the device is in use.  
     
     
         39 . The device of  claim 29 , wherein the insulating means are integral with the body and define at least one raised portion, the at least one raised portion being configured to prevent tissue from making physical and/or electrical contact with the active element until the active element is deployed.  
     
     
         40 . The device of  claim 29 , wherein the insulating means includes an electrically insulating sheath disposed over the body, the insulating sheath defining at least one raised portion configured to prevent the patient's tissue from coming into contact with the active element until the active element is deployed.  
     
     
         41 . The device of  claim 29 , wherein the active element is shaped as a ring and wherein the insulating means are integral with the distal end of the body, the ring-shaped active element being configured to be recessed away from the distal end of the body until fully energized.  
     
     
         42 . An electrosurgical device adapted for insertion into tissue, comprising: 
 a device body,    an RF energizable active element disposed within the device body, and    an insulating structure, wherein at least one of the device body and the insulating structure is configured to insulate the active element from the tissue until the active element is sufficiently energized to be therapeutically effective when the active element is brought into contact with the tissue.