Patent Abstract:
The present disclosure relates to systems, devices and methods for positioning and placing multiple electrodes in a target surgical site. An introducer is provided for facilitating the insertion of a cluster of electrodes into the body of a patient for performing tissue ablation. The introducer includes a body portion including a plurality of holes formed therein for selectively receiving a respective elongated shaft of the electrodes therethrough, wherein the holes of the introducer orient and space each electrode relative to one another, wherein the introducer includes a centrally disposed hole formed therein for receiving a guide needle therethrough.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 11/238,204, filed on Sep. 29, 2005 and issued on Aug. 17, 2010 as U.S. Pat. No. 7,776,035, which claims the benefit of and priority to U.S. Provisional Application No. 60/617,337, filed on Oct. 8, 2004, the entire contents of each of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to cluster ablation electrode systems and, more particularly, to systems, devices and methods for positioning and placing multiple electrodes in a target surgical site. 
     2. Background of Related Art 
     The use of radiofrequency electrodes for ablation of tissue in a patient&#39;s body is known. In a typical situation, a radiofrequency electrode comprising an elongated, cylindrical shaft with a portion of its external surface insulated is inserted into the patient&#39;s body. The electrode typically has an exposed conductive tip, which is used to contact body tissue in the region where the heat lesion or ablation is desired. The electrode is connected to a radiofrequency power source, which provides radiofrequency voltage to the electrode, which transmits the radiofrequency current into the tissue near its exposed conductive tip. This current usually returns to the power source through a reference electrode, which may comprise a large area conductive contact connected to an external portion of the patient&#39;s body. 
     In some applications, for example, tumor ablation procedures, multiple electrodes are inserted into the body in an array to enlarge ablation volumes. 
     In a particular application, arrays of high frequency electrodes are inserted into tumors. The electrodes are typically placed in a dispersed fashion throughout the tumor volume to cover the tumor volume with uniform heat, typically below about 45° C. The electrodes may be sequentially applied with high frequency voltage so that each electrode heats in sequence its neighboring tissue and then shuts off. Then, the next electrode does the same in a time series. This sequence of cycling the voltage through the electrodes continues at a prescribed frequency and for a period of time. 
     The electrode systems discussed above are limited by the practical size of lesion volumes they produce. Accordingly, electrodes with cooled conductive tips have been proposed. With cooling, radiofrequency electrode tips generally produce larger lesion volumes compared with radiofrequency electrodes, which are not cooled. For example, standard single cylindrical electrodes, with cooled tips, as described above, may make lesion volumes up to 3 to 4 cm in diameter in living tissue (e.g., the liver) by using cannulae of 1 to 2 mm in diameter and having exposed tip lengths of several centimeters. 
     Desirably, a configuration of radiofrequency electrodes, which can accomplish ablation in the range of 4 to 6 cm diameter or greater for the purpose of adequately treating large cancerous tumors in the body are necessary to effectively destroy the tumor and combat cancerous cells from spreading. It is further necessary that such an electrode system involve a simple geometry, reduced numbers of tissue insertions, facilitate planning of needle placement, and facilitate planning of heat ablation geometry and distribution. 
     An electrode system, which can be easily inserted into an organ or through the skin with minimal risk of hemorrhage and discomfort to the patient, is desirable. 
     According to yet another aspect of the present disclosure, an introducer is provided for facilitating the insertion of a cluster of electrodes into the body of a patient for tissue for performing tissue ablation. The introducer includes a body portion including a plurality of holes formed therein for selectively receiving a respective elongated shaft of the electrodes therethrough, wherein the holes of the introducer orient and space each electrode relative to one another, wherein the introducer includes a centrally disposed hole formed therein for receiving a guide needle therethrough. 
     The introducer may further include a distal introducer including a plurality of arrays of hole clusters formed therein each arranged in a linear row, wherein the rows of hole clusters are equally spaced from one another; and a proximal introducer including a plurality of arrays of holes formed therein each arranged in a linear row, wherein the rows of holes are equally spaced from one another. 
     The holes of each radial row of holes of the proximal introducer may be equally spaced from one another. In an embodiment, the proximal introducer includes six arrays of holes formed, wherein the rows of holes of the proximal introducer alternate between rows of six holes and rows of seven holes. 
     Each cluster of holes of the distal introducer may include a radially inner-most hole and a pair of radially outer-most holes. The radially outer-most holes may be offset an angle from an axis extending through the inner-most holes of each respective array of hole clusters. The inner-most holes of each radial row of clusters of the distal introducer may be equally spaced from one another. 
     The distal introducer may include six arrays of clusters formed therein arranged in a linear row. The rows of clusters of the distal introducer may alternate between rows of six clusters and rows of seven clusters. 
     Systems or devices which facilitate the positioning and placement of the radiofrequency electrodes relative to one another and relative to the target tissue volume are also desirable. 
     SUMMARY 
     The present disclosure relates to systems, devices and methods for positioning and placing multiple electrodes in a target surgical site. 
     According to an aspect of the present disclosure an electrode system is provided for use with a high frequency generator to induce coherent high frequency heat ablation volumes within targeted tissue of a patient. The electrode system includes a hub and at least three electrodes. Each electrode includes a substantially rigid elongated shaft extending from the hub and terminating in a sealed distal end section having an exposed conductive tip portion configured to be inserted into the targeted tissue and adapted at a proximal end section to be coupled to a high frequency generator to simultaneously apply an equal output voltage to each of the exposed conductive tip portions. Each electrode further includes a closed-loop fluid communication channel pathway which includes an inflow opening adapted for connection to a coolant fluid supply, and a channel portion in fluid communication with the inflow opening. The channel portion extends distally inside the conductive tip portion to carry coolant to the inside of the conductive tip portion and further extends proximally back to an outlet opening adapted to carry coolant away from the conductive tip portion. 
     The electrode system further includes an introducer including a plurality of holes formed therein for selectively receiving a respective elongate shaft of the electrodes therethrough. The holes of the introducer orient and space each electrode relative to one another. The introducer includes a centrally disposed hole formed therein for receiving a guide needle therethrough. 
     The conductive tip portions of the at least three electrodes may be arrayed relative to each other in a predetermined non-linear geometric spatial relationship relative to a longitudinal axis of the instrument such that upon application of an output voltage to the conductive tip portions, a coherent ablation isotherm is generated which encloses a desired target volume of the tissue to induce a large heat ablation volume. 
     In an embodiment, the electrode receiving holes of the introducer are each equally spaced from the central hole of the introducer. Each electrode receiving hole of the introducer includes a longitudinal axis which is parallel to one another. 
     In an embodiment, the electrode system includes a distal introducer and a proximal introducer. The distal introducer and the proximal introducer may each include a central hole formed therein for selectively receiving a guide needle therethrough, wherein the central holes function to align the distal and proximal introducers with one another. 
     The proximal introducer may include a plurality of arrays of holes formed therein each arranged in a linear row. The rows of holes are desirably equally spaced from one another. 
     It is envisioned that the holes of each radial row of holes of the proximal introducer are equally spaced from one another. The proximal introducer includes six arrays of holes formed therein arranged in a linear row. In an embodiment, the rows of holes of the proximal introducer alternate between rows of six holes and rows of seven holes. 
     It is contemplated that the distal introducer includes a plurality of arrays of hole clusters formed therein each arranged in a linear row. The rows of hole clusters are desirably equally spaced from one another. Each cluster of holes of the distal introducer may include a radially inner-most hole and a pair of radially outer-most holes. The radially outer-most holes may be offset an angle from an axis extending through the inner-most holes of each respective array of hole clusters. 
     In an embodiment, the inner-most holes of each radial row of clusters of the distal introducer are equally spaced from one another. The distal introducer includes six arrays of clusters formed therein arranged in a linear row. The rows of clusters of the distal introducer alternate between rows of six clusters and rows of seven clusters. 
     According to another aspect of the present disclosure, a system for inducing enlargement of heat ablation volumes within tissue of a patient&#39;s body is provided. The system includes a high frequency generator for supplying an output voltage; at least three substantially rigid, elongated electrodes adapted to be inserted into the tissue of a patient&#39;s body; and an introducer including a plurality of holes formed therein for selectively receiving a respective elongate shaft of the electrodes therethrough. Each of the at least three electrodes has exposed conductive tip portions arranged in a predetermined parallel relationship and a closed-loop fluid communication channel pathway. The channel pathway includes an inflow opening adapted for connection to a coolant fluid supply, and a channel portion in fluid communication with the inflow opening. The channel portion extends distally inside the conductive tip portion to carry coolant to the inside of the conductive tip portion and further extends proximally back to an outlet opening adapted to carry coolant away from the conductive tip portion. 
     The holes of the introducer orient and space each electrode relative to one another. The introducer includes a centrally disposed hole formed therein for receiving a guide needle therethrough. 
     The introducer includes a distal introducer including a plurality of arrays of hole clusters formed therein each arranged in a linear row, wherein the rows of hole clusters are equally spaced from one another; and a proximal introducer including a plurality of arrays of holes formed therein each arranged in a linear row, wherein the rows of holes are equally spaced from one another. 
     The holes of each radial row of holes of the proximal introducer may be equally spaced from one another. The proximal introducer may include six arrays of holes formed. The rows of holes of the proximal introducer alternate between rows of six holes and rows of seven holes. Each cluster of holes of the distal introducer may include a radially inner-most hole and a pair of radially outer-most holes, wherein the radially outer-most holes may be offset an angle from an axis extending through the inner-most holes of each respective array of hole clusters. The inner-most holes of each radial row of clusters of the distal introducer may be equally spaced from one another. The distal introducer may include six arrays of clusters formed therein arranged in a linear row. The rows of clusters of the distal introducer may alternate between rows of six clusters and rows of seven clusters. 
     According to yet another aspect of the present disclosure, a process for heat ablation of tissue in a patient is provided. The process includes the steps of providing an electrode system for inducing enlargement of heat ablation volumes within tissue of a patient&#39;s body. The electrode system includes a high frequency generator for supplying an output voltage; at least three substantially rigid, elongated electrodes adapted to be inserted into the tissue of a patient&#39;s body; and an introducer including a plurality of holes formed therein for selectively receiving a respective elongate shaft of the electrodes therethrough. Each of the at least three electrodes has an exposed conductive tip portion arranged in a predetermined parallel relationship and a closed-loop fluid communication channel pathway. The channel pathway includes an inflow opening adapted for connection to a coolant fluid supply, and a channel portion in fluid communication with the inflow opening. The channel portion extends distally inside the conductive tip portion to carry coolant to the inside of the conductive tip portion and further extends proximally back to an outlet opening adapted to carry coolant away from the conductive tip portion. 
     The holes of the introducer orient and space each electrode relative to one another. The introducer includes a centrally disposed hole formed therein for receiving a guide needle therethrough. 
     The method further includes inserting the electrodes into desired holes of the introducer in order to position each electrode relative to one another; inserting the electrodes into the tissue; applying substantially the same radiofrequency output through the electrodes to a targeted tissue volume to produce coherent heating of the targeted tissue volume; raising the radiofrequency output to a level that induces enlargement of the volume of heat ablation in the tissue near the electrodes; and cooling each electrode by circulating a cooling fluid through a closed-loop fluid communication channel pathway formed in each of the electrodes. 
     It is envisioned that the introducer includes a distal introducer including a plurality of arrays of hole clusters formed therein each arranged in a linear row, wherein the rows of hole clusters are equally spaced from one another; and a proximal introducer including a plurality of arrays of holes formed therein each arranged in a linear row, wherein the rows of holes are equally spaced from one another. 
     The method further includes the steps of placing the electrodes into desired holes of the proximal introducer; placing the distal introducer in a desired position on the skin surface of the patient; introducing the electrodes into the patient through the holes provided in the distal introducer; and advancing the electrodes through the distal introducer. 
     The method may further include the steps of placing a guide needle into a central hole formed in the distal introducer; inserting the guide needle into the body of the patient such that a tip of the guide needle is placed in close proximity to a target tissue; and placing the distal introducer against the skin of the patient. 
     The method may further include the steps of withdrawing the guide needle from the distal introducer; and inserting the electrodes into the body of the patient through the holes formed in the distal introducer. 
     The method may still further include the step of advancing the electrodes through the distal introducer until the tips thereof are in close proximity to the target tissue. 
     For a better understanding of the present disclosure and to show how it may be carried into effect, reference will now be made by way of example to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various preferred embodiments of the presently disclosed systems, devices and methods are disclosed herein with reference to the drawings wherein: 
         FIG. 1  is a schematic illustration of an ablation electrode array system according to the present disclosure showing multiple radiofrequency electrodes being positioned in a patient&#39;s organ for producing heat ablation of a targeted tissue area; 
         FIG. 2  is a perspective view of an electrode introducer according to an embodiment of the present disclosure; 
         FIG. 3  is a perspective view of the electrode introducer of  FIG. 2  including a needle extending therefrom; 
         FIG. 4  is a perspective view of the electrode array system of  FIG. 1  including a two piece combined electrode introducer according to another embodiment of the present disclosure; 
         FIG. 5  is a perspective view of a first electrode introducer of the two piece combined electrode introducer shown in  FIG. 4 ; 
         FIG. 6  is a top plan view of the first electrode introducer of  FIG. 5 ; 
         FIG. 7  is a perspective view of a second electrode introducer of the two piece combined electrode introducer shown in  FIG. 4 ; 
         FIG. 8  is a top plan view of the second electrode introducer shown in  FIG. 7 ; and 
         FIG. 9  is an enlarged view of the indicated area of detail of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring initially to  FIG. 1 , an embodiment of a multiple electrode arrangement such as an ablation electrode array system, in accordance with the present disclosure, is generally designated “E”. Electrode array system “E” includes a plurality of electrodes  1 ,  2  and  3 , which are to be inserted into an organ “OR” of a human body or any other body tissue. Respective distal tips  1   b ,  2   b  and  3   b  of electrodes  1 ,  2  and  3  are un-insulated and conductively exposed so that electrical currents induce heating within the tissue or organ “OR”. A targeted volume of tissue “T” is shown in sectional view and may represent, for example, a tumor or other abnormality in a human body. 
     Electrodes  1 ,  2  and  3  are connected by respective wires or cables  10 ,  11  and  12  to an electrosurgical generator  16 . Electrosurgical generator  16  may be a radiofrequency or high frequency type generator. Electrosurgical generator  16  includes control elements, illustrated by block  17 , which may, for example, increase the radiofrequency power output of electrodes  1 ,  2  and  3 , control temperature when electrode array system “E” or satellite sensors (not shown) include temperature sensors, monitor or control impedance, power, current, voltage, or other output parameters. Electrosurgical generator  16  may include a display or screen, illustrated by block  18 , within it or as a separate system, for providing a display of heating parameters such as temperature for one or more of electrodes  1 ,  2  and  3 , impedance, power, current, or voltage of the radiofrequency output. Such individual display readings are illustrated by the reference letters R 1  . . . RN. 
     Electrode system “E” further includes a reference electrode  19 , which may be placed in contact with the skin of a patient or an external surface of organ “OR” with a connection  20  to electrosurgical generator  16 . Reference electrode  19  and connection  20  serves as a path for return current from electrosurgical generator  16  through electrodes  1 ,  2  and  3 . 
     Each electrode  1 ,  2  and  3  includes a rigid shaft  1   a ,  2   a  and  3   a , respectively, which enables electrodes  1 ,  2  and  3  to be easily urged into the body tissue or organ “OR”. Each electrode  1 ,  2  and  3  terminates pointed distal tips  1   b ,  2   b  and  3   b , respectively. Desirably, a portion of the external surface of each electrode  1 ,  2  and  3  is covered with an insulating material, as indicated by hatched line areas in  FIG. 1 . Distal tips  1   b ,  2   b  and  3   b  are connected, through respective shafts  1   a ,  2   a  and  3   a  to cables  10 ,  11  and  12 , respectively, and thereby to electrosurgical generator  16 . 
     By way of example only and in no way to be considered as limiting, electrosurgical generator  16  may be a radiofrequency generator with frequency between about 100 kilohertz (kHz) to several hundred megahertz (MHz). Additionally, electrosurgical generator  16  may have power output ranging from several watts to several hundred watts, depending on the clinical application. 
     Desirably, electrodes  1 ,  2  and  3  may be raised to the same radiofrequency voltage potential from electrosurgical generator  16 . The array of electrodes thus becomes, in effect, a larger, coherent electrode including the individual electrode tips  1   b ,  2   b  and  3   b . Thus, the heating effect of the array of electrodes is substantially similar to that achieved by one large single electrode. 
     As seen in  FIG. 1 , by way of illustration only, a targeted region to be ablated is represented in sectional view by the line “T”. It is desired to ablate the targeted region “T” by fully engulfing targeted region “T” in a volume of lethal heat elevation. The targeted region “T” may be, for example, a tumor which has been detected by an image scanner  30 . For example, CT, MRI, or ultrasonic image scanners may be used, and the image data transferred to a computer  26 . As an alternate example, an ultrasonic scanner head  15  may be disposed in contact with organ “OR” to provide an image illustrated by lines  15 A. A data processor  16  may be connected to the display devices to visualize targeted region “T” and/or ablation zone “T 1 ” in real time during the ablation procedure. 
     The image representation of the scan may be displayed on display unit  22  to represent the size and position of target region “T”. Placement of electrodes  1 ,  2  and  3  may be predetermined based on such image data as interactively determined by real-time scanning of organ “OR”. Electrodes  1 ,  2  and  3  are inserted into the tissue by freehand technique by a guide block or introducer  100  with multi-hole templates, or by stereotactic frame or frameless guidance, as known by those skilled in the art. 
     Desirably, an array of electrodes  1 ,  2  and  3  are connected to the same radiofrequency voltage from electrosurgical generator  16 . Accordingly, the array of electrodes  1 ,  2  and  3  will act as a single effectively larger electrode. The relative position and orientation of electrodes  1 ,  2  and  3  enable the creation of different shapes and sizes of ablation volumes. For example, in  FIG. 1 , dashed line  8  represents the ablation isotherm in a sectional view through organ “OR”. Such an ablation isotherm may be that of the surface achieving possible temperatures of approximately 50° C. or greater. At that temperature range, sustained for approximately 30 seconds to approximately several minutes, tissue cells will be ablated. The shape and size of the ablation volume, as illustrated by dashed line  8 , may accordingly be controlled by the configuration of the electrode array, the geometry of the distal tips  1   b ,  2   b  and  3   b  of electrodes  1 ,  2  and  3 , respectively, the amount of RF power applied, the time duration that the power is applied, cooling of the electrodes, etc. 
     Turning now to  FIGS. 2 and 3 , a guide block or introducer, in accordance with an embodiment of the present disclosure, is generally designated as  100 . Introducer  100  includes a plurality of electrode through-holes  102  formed therein. Desirably, as seen in  FIGS. 2 and 3 , introducer  100  includes a first set of three holes  102   a ,  102   b  and  102   c  formed therein. Preferably, holes  102   a ,  102   b  and  102   c  are spaced an equal distance apart from one another. As such, holes  102   a ,  102   b  and  102   c  define an equilateral triangle. Each hole  102   a ,  102   b  and  102   c  defines a longitudinal axis “Xa, Xb and Xe”. Preferably, longitudinal axes “Xa, Xb and Xc” are at least substantially parallel to one another. Desirably, holes  102   a ,  102   b  and  102   c  are sized and dimensioned to slidably receive a respective electrode  1 ,  2  and  3  therein. 
     With continued reference to  FIGS. 2 and 3 , introducer  100  further includes a central hole  104  formed therethrough. Central hole  104  defines a central longitudinal axis “X”. Preferably, the central longitudinal “X” axis is at least substantially parallel to the longitudinal axes “Xa, Xb and Xc” of holes  102   a ,  102   b  and  102   c . Desirably, central hole  104  is located at the intersection of axes or lines extending orthogonally through the longitudinal axes “Xa, Xb and Xe” of holes  102   a ,  102   b  and  102   c.    
     As seen in  FIGS. 2 and 3 , introducer  100  may have a substantially triangular geometric configuration including corners  106   a ,  106   b  and  106   c  and side walls  108   a ,  108   b  and  108   c . It is envisioned that a hole  102   a ,  102   b  and  102   c  is formed near a respective corner  106   a ,  106   b  and  106   c  of introducer  100 . Desirably, each corner  106   a ,  106   b  and  106   c  of introducer  100  is rounded or radiused. Additionally, side walls  108   a ,  108   b  and  108   c  may be planar and, desirably, as seen in  FIGS. 2 and 3 , may be concave. 
     In accordance with the present disclosure, introducer  100  functions to hold or maintain electrodes  1 ,  2  and  3  of electrode system “E” substantially parallel to one another and at a defined distance from one another during the use thereof. It is envisioned that a guide needle  110  may be advanced through center hole  104  of introducer  100  and advanced to the desired target tissue using known medical imaging techniques (e.g., ultrasound, computer tomography, magnetic resonance imaging, X-ray, CT scan, etc.) 
     In one embodiment, as seen in  FIG. 3 , it is envisioned that center hole  104  may be eliminated and guide needle  110  may be operatively secured to the center of introducer  100  (i.e., at the central longitudinal “X” axis). In the present embodiment, introducer  100  may be introduced or advanced to the target tissue in a manner similar to that described above. 
     Turning now to  FIGS. 4-9 , an introducer, in accordance with an alternative embodiment of the present disclosure, is generally designated as  200  and is shown in operative association with a cluster electrode system “E”. Introducer  200  includes a first or proximal introducer  210  and a second or distal introducer  220 . Desirably, as seen in  FIG. 4 , proximal introducer  210  and distal introducer  220  are used in cooperation with or in combination with one another to hold or maintain electrodes  1 ,  2  and  3  of electrode system “E” substantially parallel to one another, at a defined distance from one another and/or at a defines location relative to one another during the use thereof. 
     Turning now to  FIGS. 5 and 6 , proximal introducer  210  includes a plurality of radially oriented rows  212  of holes  214  formed therein. Preferably, each row  212  is equally spaced from one another by an angle “Θ” relative to one another. As seen in  FIGS. 5 and 6 , proximal introducer  210  may include six (6) rows  212  of holes  214  which are spaced from one another by an angle “Θ” approximately equal to 60°. Desirably, each hole  214  includes a longitudinal axis which is at least substantially parallel to one another. In accordance with an embodiment of the present disclosure, each hole  214  may have a diameter of approximately 0.085 in. (2.16 mm) 
     Proximal introducer  210  further includes a central hole  216  formed therethrough. Central hole  216  defines a central longitudinal axis “X”. Preferably, the central longitudinal “X” axis is at least substantially parallel to the longitudinal axes of holes  214 . Desirably, central hole  216  is located at the intersection of rows  212 . 
     As seen in  FIGS. 5 and 6 , a first set of rows  212   a  includes six (6) holes  214   a  formed therealong. Desirably, rows  212   a  of holes  214   a  are spaced from one another by an angle “Φ” approximately equal to 120°. A second set or rows  212   b  includes seven (7) holes  214   b  formed therealong. Desirably, rows  212   b  of holes  214   b  are spaced from one another by an angle “Φ” approximately equal to 120°. 
     Preferably, the respective holes  214   a  of the first set of rows  212   a  define an equilateral triangle therebetween. Accordingly, in one embodiment, the distance between respective inner-most holes  214   a   1  is approximately 0.984 in. (25.0 mm). The distance between respective second inner-most holes  214   a   2  is approximately 1.378 in. (35.0 mm). The distance between respective third inner-most holes  214   a   3  is approximately 1.772 in. (45.0 mm). The distance between respective fourth inner-most holes  214   a   4  is approximately 2.165 in. (55.0 mm). The distance between respective fifth inner-most holes  214   a   5  is approximately 2.559 in. (65.0 mm). The distance between respective sixth inner-most holes  214   a   6  is approximately 2.953 in. (75.0 mm). 
     Preferably, the respective holes  214   b  of the second set of rows  212   b  also define an equilateral triangle therebetween. Accordingly, in one embodiment, the distance between respective inner-most holes  214   b   1  is approximately 0.787 in. (20.0 mm). The distance between respective second inner-most holes  214   b   2  is approximately 1.181 in. (30.0 mm). The distance between respective third inner-most holes  214   b   3  is approximately 1.575 in. (40.0 mm). The distance between respective fourth inner-most holes  214   b   4  is approximately 1.969 in. (50.0 mm). The distance between respective fifth inner-most holes  214   b   5  is approximately 2.362 in. (60.0 mm). The distance between respective sixth inner-most holes  214   b   6  is approximately 2.756 in. (70.0 mm). The distance between respective seventh inner-most holes  214   b   7  is approximately 3.150 in, (80.0 mm). 
     Desirably, as seen in  FIGS. 5 and 6 , proximal introducer  210  may have a substantially circular geometric profile. In one embodiment, proximal introducer  210  may have a diameter approximately 4.0 in. (102.0 mm). It is further envisioned that proximal introducer  210  may have a thickness of approximately 0.38 in. (9.65 mm). 
     Turning now to  FIGS. 7-9 , distal introducer  220  is similar to proximal introducer  210  and will only be discussed in detail to the extent necessary to identify differences in construction and operation. Distal introducer  220  includes a plurality of radially oriented rows  222  of holes  224  formed therein. Preferably, distal introducer  220  includes six (6) rows  222  of holes  224  which are spaced from one another by an angle “Θ” of approximately 60°. In accordance with an embodiment of the present disclosure, each hole  224  may have a diameter of approximately 0.085 in. (2.16 mm). Preferably, the number and location of holes  224  of distal introducer  220  is substantially identical to the number and location of holes  214  of proximal introducer  210 . 
     As seen in  FIGS. 7 and 8 , a first set of rows  222   a  includes six (6) holes  224   a  formed therealong. Desirably, rows  222   a  of holes  224   a  are spaced from one another by an angle “Φ” of approximately 120°. A second set or rows  222   b  includes seven (7) holes  224   b  formed therealong. Desirably, rows  222   b  of holes  224   b  are spaced from one another by an angle “Φ” of approximately 120°. 
     As seen in  FIGS. 7 and 8 , a central hole  226  formed therethrough. Central hole  226  defines a central longitudinal axis “X”. Preferably, the central longitudinal “X” axis is at least substantially parallel to the longitudinal axes of holes  224 . Desirably, central hole  226  is located at the intersection of rows  222 . 
     As seen in  FIGS. 7-9 , distal introducer  220  further includes rows  223   a  and  225   a  of holes  226   a  formed on either side of each row of holes  224   a  the first set of rows  222   a  and rows  223   b  and  225   b  of holes  226   b  formed on either side of each row of holes  224   b  of the second set of rows  222   b . Desirably, each row  223   a  and  225   a  includes six (6) holes corresponding, one each, to holes  224   a  for each row  222   a . Additionally, each row  223   b  and  225   b  desirably includes seven (7) holes corresponding, one each, to holes  224   b  for each row  222   b.    
     As seen in  FIGS. 8 and 9 , holes  226   a , of rows  223   a  and  225   a , and holes  226   b , of rows  223   b  and  225   b , are offset a radial distance outward from corresponding holes  224   a  and  224   b , respectively. In particular, a central axis of each hole  226   a  is desirably spaced a distance “d” from a central axis of a corresponding hole  224   b  of the first set or rows  222   b  by an amount of approximately 0.198 in. (5.0 mm) at an angle “α” of approximately 30.00° relative to an axis “R” extending radially through holes  224   b  (e.g., a diameter or radius of distal introducer  220 ). 
     Desirably, radially outer-most holes  226   b  of rows  223   b  and  225   b  and radially outer-most hole  224   b  of row  222   b  define a cluster “C” with holes  224   b  and  226   b  is a substantially equilateral configuration. As such, cluster “C” may receive three smaller or thinner needles to achieve the same effect as compared to a single larger needle. A plurality of clusters “C” are desirably defines along each row  222   a  and  222   b.    
     Desirably, a central axis of each hole  226   b  is also spaced a distance “d” from a central axis of a corresponding hole  224   b  of the second set or rows  222   b  by an amount of approximately 0.198 in. (5.0 mm) at an angle “α” of approximately equal to 29.67° relative to an axis “R” extending radially through holes  224   a  (e.g., a diameter or radius of distal introducer  220 ). 
     Desirably, as seen in  FIGS. 7 and 8 , distal introducer  220  may have a substantially circular geometric profile. In one embodiment, distal introducer  220  may have a diameter of approximately 4.0 in. (102.0 mm). It is further envisioned that distal introducer  220  may have a thickness of approximately 0.375 in. (9.925 mm). While a circular geometric profile is shown, it is envisioned and within the scope of the present disclosure that any geometric profile may be used, such as, for example, hexagonal, rectangular, star-shaped, etc. 
     It is envisioned that proximal introducer  210  and distal introducer  220  may be fabricated from a rigid, non-conductive material (e.g., plastic, polycarbonate, etc.). 
     Referring back to  FIG. 4 , in accordance with one method of use, electrodes  1 ,  2  and  3  of electrode array system “E” are positioned in holes  214   a  of rows  212   a  or in holes  214   b  of rows  212   b , depending on the particular surgical procedure and depending on the size and characteristics of the organ to be operated on. Desirably, electrodes  1 ,  2  and  3  are placed solely in corresponding holes  214   a  of rows  212   a  or in holes  214   b  of rows  212   b . Desirably, electrodes  1 ,  2  and  3  are positioned in introducer  210  in substantially equilateral triangular configurations. Depending on the size of the target lesion and the particular operative parameters to be employed and/or delivered from electrosurgical generator  16 , electrodes  1 ,  2  and  3  may be placed in holes  214   a  or  214   b  which are either closer or further from central hole  216 . 
     Prior to, concomitantly therewith, or subsequent thereto, distal introducer  220  is placed against the body surface of the patient at a location in the proximity to where electrodes  1 ,  2  and  3  are to be introduced into the body. Desirably, a guide needle  110  (see  FIG. 3 ) extending from the center of distal introducer  220  may be used to position the location of distal introducer  220  relative to the body surface of the patient. 
     With the relative distance and orientation of electrodes  1 ,  2  and  3  of electrode array system “E” set by proximal introducer  210  and with distal introducer  220  positioned against the body surface of the patient, electrodes  1 ,  2  and  3  of electrode array system “E” are then inserted into desired and/or pre-determined holes  224   a ,  224   b  of rows  222   a  or  222   b , respectively, or into desires and/or predetermined holes  226   a ,  226   b  of rows  223   a ,  225   a  or rows  223   b ,  225   b.    
     Introducer  200 , including proximal introducer  210  and distal introducer  220  help to facilitate placement of electrodes  1 ,  2  and  3  of electrode array system “E” by the clinician. As mentioned above, introducer  200  may function to maintain electrodes  1 ,  2  and  3  substantially parallel to one another, and at a prescribed spacing relative to one another. The prescribed spacing is determined in part by the energy delivery to the organ which may have an effect on the overall size of the lesion. Additionally, introducer  200  and, in certain instances guide needle  110 , aid the clinician in holding electrodes  1 ,  2  and  3  at the appropriate and/or desired depth and at a substantially equal depth to one another. 
     It is understood that variations in the choice of electrical output parameters from the electrosurgical generator, to control or monitor the electrode array ablation process, may vary widely depending on the operator&#39;s experience, technique, or preference. For example, in the embodiments above, a common RF voltage is applied to all of the electrodes of the array simultaneously. As an alternate embodiment, in accordance with the present disclosure, the clinician may choose to control the RF current to the individual electrodes of the array or the total current of the array as a whole. Voltage variations on each electrode could be applied to achieve constant current output from each electrode. Alternatively, constant power output from each electrode may be sought in some clinical settings. Voltage variations or phases between electrodes may be implemented to achieve desired temperature distribution in the tissue as monitored by temperature sensors in the tissue or by visualization of temperature distribution using thermally sensitive MRI scanning, for example. Accordingly, the choice of electrical output type, sequence, and levels and the distribution of the electrodes of the array should be considered to have wide variations within the scope of the present disclosure. 
     In view of the foregoing considerations, as would be apparent by persons skilled in the art, implementations and systems should be considered broadly and with reference to the claims set forth below.

Technology Classification (CPC): 0