Patent Publication Number: US-2011054457-A1

Title: System and Method for Performing an Electrosurgical Procedure Using an Imaging Compatible Electrosurgical System

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to energy-based apparatuses, systems and methods. More particularly, the present disclosure is directed to a system and method for performing an electrosurgical procedure using an imaging compatible electrosurgical system. 
     2. Background of Related Art 
     Energy-based tissue treatment is well known in the art. Various types of energy (e.g., electrical, ultrasonic, microwave, cryo, heat, laser, etc.) are applied to tissue to achieve a desired result. Electrosurgery involves application of high radio frequency electrical current to a surgical site to cut, ablate, coagulate or seal tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency energy from the electrosurgical generator to the tissue and a return electrode carries the current back to the generator. In monopolar electrosurgery, the source electrode is typically part of the surgical instrument held by the surgeon and applied to the tissue to be treated. A patient return electrode is placed remotely from the active electrode to carry the current back to the generator. 
     In the case of tissue ablation, high radio frequency electrical current is applied to a targeted tissue site to create an ablation volume. The resulting ablation volume may then be observed and various ablation metrics may be measured and recorded. Typically, ablation metrics are obtained as scanned data obtained through use of imaging devices such as CT, MRI, PET, or other tomographic or X-ray devices. However, images obtained using such scanning techniques during an electrosurgical procedure, such as tissue ablation, are often distorted due to interference from the generator, electrosurgical instruments, and cables or wires connecting the electrosurgical instruments to the generator. 
     SUMMARY 
     According to an embodiment of the present disclosure, a method for performing an electrosurgical procedure includes the steps of supplying energy from an energy source to tissue and continuously receiving, as input, an imaging signal generated by an imaging device adapted to image tissue. The method also includes modifying the supply of energy from the energy source to tissue based on the imaging signal. 
     According to another embodiment of the present disclosure, a method for performing an electrosurgical procedure includes the step of supplying energy from a generator to one or more electrosurgical instruments adapted to apply energy to tissue. The method also includes the step of continuously receiving, as input, an imaging signal generated by an imaging device adapted to image tissue. The method also includes the step of modifying the supply of energy from the energy source to the electrosurgical instrument based on the imaging signal such that the supply of energy from the energy source to the electrosurgical instrument is either terminated or diverted to an electrical load. 
     According to another embodiment of the present disclosure, an electrosurgical system adapted for use with an imaging device includes an energy source adapted to supply energy to one or more electrosurgical instruments configured to apply energy to tissue and an imaging device operably coupled to the energy source and adapted to image tissue. The imaging device is configured to continuously generate an imaging signal. The supply of energy to the one or more electrosurgical instruments is either terminated or diverted to an electrical load based on the imaging signal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the present disclosure are described herein with reference to the drawings wherein: 
         FIGS. 1A and 1B  are schematic block diagrams of an electrosurgical system according to an embodiment of the present disclosure; 
         FIG. 1C  is a schematic block diagram of an electrosurgical system according to another embodiment of the present disclosure; 
         FIG. 2  is a schematic block diagram of a generator according to one embodiment of the present disclosure; 
         FIG. 3A  is a schematic block diagram of an electrosurgical system according to another embodiment of the present disclosure; 
         FIG. 3B  is a timing diagram illustrating operation of the electrosurgical system of  FIG. 3A ; 
         FIG. 4A  is a schematic block diagram of an electrosurgical system according to another embodiment of the present disclosure; 
         FIG. 4B  is a timing diagram illustrating operation of the electrosurgical system of  FIG. 4A ; and 
         FIG. 5  is a flow chair illustrating a method for performing an electrosurgical procedure according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Particular embodiments of the present disclosure are described hereinbelow with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. 
     An electrosurgical generator according to the present disclosure can perform monopolar and bipolar electrosurgical procedures, including tissue ablation procedures. The generator may include a plurality of outputs for interfacing with various electrosurgical instruments (e.g., a microwave antenna, a monopolar active electrode, return electrode, bipolar electrosurgical forceps, footswitch, etc.). Further, the generator includes electronic circuitry configured to generate electrosurgical energy (e.g., RF, microwave, etc.) specifically suited for various electrosurgical modes (e.g., cut, coagulate, desiccate, fulgurate, etc.) and procedures (e.g., ablation, vessel sealing, etc.). 
       FIG. 1A  is a schematic illustration of a monopolar electrosurgical system  1  according to one embodiment of the present disclosure. The system  1  includes an electrosurgical instrument  2  having one or more electrodes for treating tissue of a patient P. The instrument  2  is a monopolar type instrument including one or more active electrodes (e.g., electrosurgical cutting probe, ablation electrode(s), etc.). Electrosurgical energy is supplied to the instrument  2  by a generator  20  via a supply line  4 , which is connected to an active terminal  30  ( FIG. 2 ) of the generator  20 , allowing the instrument  2  to coagulate, seal, ablate and/or otherwise treat tissue. The energy is returned to the generator  20  through a return electrode  6  via a return line  8  at a return terminal  32  ( FIG. 2 ) of the generator  20 . 
       FIG. 1B  is a schematic illustration of a bipolar electrosurgical system  3  according to the present disclosure. The system  3  includes a bipolar electrosurgical forceps  10  having one or more electrodes for treating tissue of a patient P. The electrosurgical forceps  10  include opposing jaw members having an active electrode  14  and a return electrode  16 , respectively, disposed therein. The active electrode  14  and the return electrode  16  are connected to the generator  20  through cable  18 , which includes the supply and return lines  4 ,  8  coupled to the active and return terminals  30 ,  32 , respectively ( FIG. 2 ). The electrosurgical forceps  10  are coupled to the generator  20  at a connector  21  having connections to the active and return terminals  30  and  32  (e.g., pins) via a plug disposed at the end of the cable  18 , wherein the plug includes contacts from the supply and return lines  4 ,  8 . 
       FIG. 1C  shows a diagram of an ablation antenna assembly  30  according to the present disclosure. In embodiments, antenna assembly  30  is a microwave antenna assembly adapted to deliver microwave energy from generator  20  to tissue. The antenna assembly  30  generally includes a radiating portion  12  that may be coupled by a feedline  34  (or shaft) via a conduit  36  to a connector  38 , which may further connect the assembly  30  to the generator  20 . Assembly  30  includes an ablation probe assembly (e.g., dipole antenna, helical antenna, etc.). A distal portion  32  of radiating portion  12  includes a tip  46  configured to allow for insertion into tissue with minimal resistance. A junction member  44  is located between a proximal portion  42  and distal portion  32  such that a compressive force may be applied by distal and proximal portions  44 ,  42  upon junction member  44 . 
       FIG. 2  shows a schematic block diagram of the generator  20  having a controller  24 , a high voltage DC power supply  27  (“HVPS”) and an energy output stage  28  configured to output electrosurgical energy (e.g., microwave, RF, etc) from generator  20 . The HVPS  27  is connected to a conventional AC source (e.g., electrical wall outlet) and provides high voltage DC power to the energy output stage  28 , which then converts high voltage DC power into electrosurgical energy and delivers the electrosurgical energy to the active terminal  30 . In some embodiments ( FIGS. 1A and 1B ), the electrosurgical energy is returned to the energy output stage  28  via the return terminal  32 . 
     The generator  20  may include a plurality of connectors to accommodate various types of electrosurgical instruments (e.g., instrument  2 , electrosurgical forceps  10 , antenna assembly  30 , etc.). Further, the generator  20  may operate in monopolar or bipolar modes by including a switching mechanism (e.g., relays) to switch the supply of energy between the connectors, such that, for instance, when the instrument  2  is connected to the generator  20 , only the monopolar plug receives electrosurgical energy. 
     The controller  24  includes a microprocessor  25  operably connected to a memory  26 , which may be volatile type memory (e.g., RAM) and/or non-volatile type memory (e.g., flash media, disk media, etc.). The microprocessor  25  includes an output port that is operably connected to the HVPS  27  and/or the energy output stage  28  allowing the microprocessor  25  to control the output of the generator  20  according to either open and/or closed control loop schemes. Those skilled in the art will appreciate that the microprocessor  25  may be substituted by any logic processor or analog circuitry (e.g., control circuit) adapted to perform the calculations discussed herein. 
     Generally, the present disclosure relates to the use of a generator (e.g., generator  20 ) in an imaging setting or a so-called “MRI suite” setting. Specifically, electrosurgical energy (e.g., microwave, RF, etc.) generated by an electrosurgical generator is attracted to high-strength magnets employed by imaging devices or scanners (e.g., CT scanners, MRI scanners, etc.). This attraction causes distortions to image data generated by such imaging devices when energy is being generated in close proximity to the imaging device during an imaging procedure. This problem may be addressed by placing the generator outside the suite and running cables through the wall into the magnet area. 
     In one embodiment, image distortion is addressed using filters (e.g., notch filters) to minimize the interference between the generator and the imaging device. In this scenario, suitable filters may be incorporated within the generator and/or the imaging device. 
     In other embodiments, interference between the generator and the imaging device is minimized by modifying or affecting generator output such that operation of the generator is compatible with operation of the imaging device in the same procedure area and/or during the same procedure. 
       FIG. 3A  illustrates an imaging compatible electrosurgical system  100  according to an embodiment of the present disclosure. Generally, system  100  includes generator  20  operably coupled to an imaging device  50  and an electrosurgical instrument, referenced as  2 , 10 , 30  to illustrate that instrument may be any one of instruments  2 ,  10 , or  30  of  FIGS. 1A ,  1 B, or  1 C, respectively. Imaging device  50  is adapted to image tissue and may be, for example without limitation, an imaging probe, an MRI device, a so-called “MRI suite”, a CT device, a PET device, X-ray device, or any combination thereof. Imaging device  50  may include a processor operably coupled with a memory (not shown) storing any suitable imaging software and/or image processing software executable as programmable instructions by the processor to cause imaging device  50  to image tissue and/or generate tissue image data. In operation of system  100 , generator  20  continuously receives an imaging signal generated by the imaging device  50  that is, in turn, processed by the controller  24 . Based on the processed imaging signal, the controller  24  controls generator output. More specifically, the imaging signal generated by the imaging device  50  is a digital timing sequence configured to continuously indicate (e.g., via binary logic) in real-time whether or not an imaging sequence is currently being performed by the imaging device  50 . Those skilled in the art will appreciate that imaging device  50  includes suitable circuitry (e.g., processor, memory, a/d converter, etc.) configured to generate the imaging signal as output and, further, that controller  24  and/or microprocessor  25  includes suitable circuitry configured to receive and process the imaging signal as input. 
     The imaging signal is processed by the controller  24  to cause the energy output stage  28  to terminate energy output from generator  20  during an imaging procedure and to allow energy output from the generator  20  while no imaging procedure is being performed by the imaging device  50 . By way of example,  FIG. 3B  shows a timing diagram illustrating net generator output during continuous processing of the imaging signal by the generator  20  during operation thereof As shown in the illustrated embodiment, while an imaging procedure is in progress, the imaging signal generated by the imaging device  50  is logic “high”, indicating an imaging procedure is currently being performed by the imaging device  50 . This, in turn, causes net generator output to the instrument  2 ,  10 ,  30  to be terminated and/or suspended by controller  24 , as indicated by a logic “low” in the illustrated timing diagram Likewise, while an imaging procedure is not currently in progress, the imaging signal generated by the imaging device  50  is logic “low”, indicating that an imaging procedure is not currently in progress. The logic low is processed by the controller  24 , which in turn, causes energy output phase  28  to output energy to the instrument  2 ,  10 ,  30  as indicated by a logic “high” in the illustrated timing diagram. In this manner, imaging procedures (e.g., MRI) and electrosurgical procedures (e.g., ablation) may be performed in close proximity and essentially during the same procedure or operation without adverse effects (e.g., image distortion) to the imaging process caused by interference from the generator  20 , instrument  2 ,  10 ,  30  and/or cables therebetween. 
       FIG. 4A  illustrates an imaging compatible electrosurgical system  200  according to another embodiment of the present disclosure. In this embodiment a switching device  40  is incorporated between the generator  20  and the instrument  2 ,  10 ,  30 . The switching device  40  is configured to continuously receive the imaging signal from the imaging device  50  in substantially the same manner as described above with respect to the embodiment of  FIGS. 3A and 3B . The switching device  40  may be, for example, an electromechanical switch activated by the imaging signal generated by the imaging device  50 . With this purpose in mind, switching device  40  includes any one or more suitable switching components and includes circuitry configured to receive and process the imaging signal from the imaging device  50  as input. Generally, the switching device  40  receives and processes the imaging signal generated by the imaging device  50  and switches generator output between instrument  2 ,  10 ,  30  and an electrical load  60  based on the processed imaging signal to substantially eliminate interference with the imaging device  50  caused by generator  20 , instrument  2 ,  10 ,  30  and cable or wire connections therebetween during an imaging procedure. More specifically, while an imaging procedure is in progress, switching device  40  diverts generator output from instrument  2 ,  10 ,  30  to electrical load  60 . Likewise, while an imaging procedure is not in progress, switching device  40  diverts generator output from electrical load  60  to instrument  2 ,  10 ,  30 . By way of example,  FIG. 4B  shows a timing diagram illustrating the switching of generator output between instrument  2 ,  10 ,  30  and electrical load  60  during continuous processing of the imaging signal by the switching device  40  during an electrosurgical procedure. As shown in the illustrated embodiment, while an imaging procedure is currently being performed by the imaging device  50 , the imaging signal generated by the imaging device  50  is logic “high”, indicating that an imaging procedure is currently being performed. As illustrated by the timing diagram, this, in turn, causes switching device  40  to switch the path of generator output away from the instrument  2 ,  10 ,  30 , as indicated by a logic “low”, to electrical load  60 , as indicated by a logic “high”. While an imaging procedure is not currently being performed by the imaging device  50 , the imaging signal generated by the imaging device  50  is logic “low”, indicating that an imaging procedure is not currently in being performed by the imaging device  50 . As illustrated by the timing diagram, this, in turn, causes switching device  40  to switch the path of generator output away from electrical load  60 , as indicated by a logic “low”, to instrument  2 ,  10 ,  30 , as indicated by a logic “high”. In this and other embodiments, generator  20 , switching device  40 , electrical load  60 , and any cable or wire connections therebetween, may be located in a room separate from the room where imaging device  50  and instrument  2 ,  10 ,  30  are located (e.g., operating room). In this scenario, any cable or wire connections between switching device  40  and imaging device  50  and/or instrument  2 ,  10 ,  30  may be passed through a structure (e.g., wall, door, floor, ceiling, etc.) from one room to another. In this manner, when switching device  40  (located outside the procedure room) diverts energy from instrument  2 ,  10 ,  30  to electrical load  60  during an imaging procedure, no energy is being transferred between switching device  40  and instrument  2 ,  10 ,  30  (inside the procedure room), thereby substantially eliminating interference with imaging device  50  caused by generator  20 , instrument  2 ,  10 , and any cable or wire connections therebetween. 
     A method for performing an electrosurgical procedure using an imaging compatible energy source according to embodiments of the present disclosure will now be described with reference to  FIG. 5  in conjunction with  FIGS. 1A-4B . 
     In step  300 , electrosurgical energy is supplied from the generator  20  to the instrument (e.g., instrument  2 , forceps  10 , etc.). In embodiments, instrument  2 ,  10 ,  30  is used to apply energy from the generator  20  to tissue (e.g., to create an ablation lesion). In step  310 , the imaging device  50  continuously generates an imaging signal, as illustrated in  FIGS. 3B and 4B . 
     In one embodiment, illustrated in  FIGS. 3A and 3B , the imaging signal is received and processed by the generator  20 . In step  320 , based on the received imaging signal, the controller  24  terminates generator output while the imaging device  50  is performing an imaging procedure and permits generator output when no imaging procedure is being performed by the imaging device  50 . 
     In another embodiment, illustrated in  FIGS. 4A and 4B , the imaging signal is received and processed by the switching device  40 . In step  330 , based on the received imaging signal, the switching device  40  switches generator output between instrument  2 ,  10 ,  30  and electrical load  60 . More specifically, the switching device  40  diverts generator output from the instrument  2 ,  10 ,  30  to the electrical load  60  while the imaging device  50  is performing an imaging procedure. Likewise, the switching device  50  diverts generator output from the electrical load  60  to the instrument  2 ,  10 ,  30  when no imaging procedure is being performed by the imaging device  50 . 
     While several embodiments of the disclosure have been shown in the drawings and/or discussed herein, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. For example, it should be understood that any of the above disclosed embodiments may be configured such that imaging device  50  generates a logic low to indicate an imaging procedure is currently being performed and, vice-versa, a logic high may indicate that no imaging procedure is currently being performed. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.