Patent Publication Number: US-9848932-B2

Title: Cool-tip thermocouple including two-piece hub

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation application of U.S. application Ser. No. 12/182,723, filed Jul. 30, 2008, now U.S. Pat. No. 8,672,937, which is a divisional application of U.S. application Ser. No. 11/495,033, filed Jul. 28, 2006, now U.S. Pat. No. 7,763,018, the entire contents of all of which are incorporated by reference herein. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to electrode thermosurgery systems and, more particularly, to cool-tip ablation electrode systems used for thermosurgery procedures and the like. 
     Background of Related Art 
     Therapeutic lesions in living bodies have been accomplished for many decades using radio-frequency (RF) and other forms of energy. The procedures have been particularly useful in the field of neurosurgery, typically where RF ablation needle electrodes (usually of elongated cylindrical geometry) are inserted into a living body. A typical form of such needle electrodes incorporates an insulated sheath from which an exposed (uninsulated) tip extends. 
     Generally, the ablation electrode is coupled between a grounded RF power source (outside the body) and a reference ground or indifferent electrode for contacting a large surface of the body. When an RF voltage is provided between the reference electrode and the inserted ablation electrode, RF current flows from the needle electrode through the body. Typically, the current density is very high near the tip of the needle electrode, which heats and destroys the adjacent tissue. 
     In the past, RF ablation electrode systems have incorporated temperature sensors, for example, in the form of a thermistor or thermocouple. In that regard, reference may be made to U.S. Pat. No. 4,411,266 to Cosman, the entire contents of which are incorporated herein by reference, for a detailed discussion of the same. Typically, the sensor is connected to a monitoring apparatus for indicating temperature to assist in accomplishing a desired lesion. As generally known, for a given tip geometry and tip temperature, lesions of a prescribed size can be made quite consistently. 
     A limitation of prior electrode ablation systems relates to the temperature of the tip. Specifically, prior needle electrodes of a given tip geometry never should effectively exceed a temperature of 100° C. At that temperature, the surrounding tissue will boil and char. Also, uncontrolled disruption, such as hemorrhage and explosive gas formation, may cause extremely hazardous and clinically dangerous effects on the patient. Consequently, the lesion size for a given electrode geometry generally has been considered to be somewhat limited by the fact that the tissue near the tip must not exceed 100° C. 
     Essentially, during RF ablation, the needle electrode temperature is highest near the tip, because the current density is the highest at that location. Accordingly, temperature falls off as a function of distance from the tip of the needle electrode, and except for possible abnormalities in tissue conductivity and so on, in a somewhat predictable and even calculable pattern. As an attendant consequence, the size of RF lesions for a given electrode geometry have been somewhat limited. 
     One proposed solution to the limitation of lesion&#39;s size has been to employ “off-axis” electrodes, for example the so called Zervas Hypophysectomy Electrode or the Gildenberg Side-Outlet electrode, as manufactured by Radionics, Inc., Burlington, Mass. However, such systems, in requiring multiple tissue punctures, increase the risk of hemorrhage, severely prolong the time of surgery and increase the level of delicacy. Also, an umbrella of off-axis lesions may not produce a desired homogenous or uniform lesion. 
     SUMMARY 
     The present disclosure relates to ablation electrode systems used for thermosurgery procedures and the like. 
     According to one aspect of the present disclosure, an ablation electrode system for use with a source of electrosurgical energy to ablate tissue in a living subject is provided. The ablation electrode system includes a handle assembly; and a needle electrode assembly supported in and extending from the handle assembly. The needle electrode assembly includes an outer tube having at least a conductive distal tip, a proximal end portion supported in the handle assembly, and defining a cavity therein; and an inner tube disposed at least partially within the cavity of the outer tube and having a proximal end portion supported within the handle assembly, the inner tube defining a lumen therein. 
     The ablation electrode system further includes a hub assembly supported within the handle assembly and fluidly connected to the needle electrode assembly. The hub assembly includes an outer shell defining a lumen therein; and an inner manifold operatively supported in the lumen of the outer shell. The inner manifold and the outer shell are configured and dimensioned so as to define a first chamber and a second chamber therebetween. The proximal end portion of the inner tube is in fluid communication with the first chamber and the proximal end portion of the outer tube is in fluid communication with the second chamber. 
     The ablation electrode system further includes an electrical conduit electrically connected to the outer tube of the needle electrode assembly; a first fluid conduit fluidly connected to the first chamber; and a second fluid conduit fluidly connected to the second chamber. 
     According to another aspect of the present disclosure, an ablation electrode system is provided and includes a handle assembly; a needle electrode assembly supported in and extending from the handle assembly. The needle electrode assembly includes an outer tube having at least a conductive distal tip, a proximal end portion supported in the handle assembly, and defining a cavity therein; and an inner tube disposed at least partially within the cavity of the outer tube and having a proximal end portion supported within the handle assembly, the inner tube defining a lumen therein. 
     The ablation electrode assembly includes a hub assembly supported within the handle assembly and fluidly connected to the needle electrode assembly. The hub assembly defines a first chamber and a second chamber; wherein the proximal end portion of the inner tube is in fluid communication with the first chamber and the proximal end portion of the outer tube is in fluid communication with the second chamber. 
     The ablation electrode assembly includes an electrical conduit electrically connected to the outer tube of the needle electrode assembly; a first fluid conduit fluidly connected to the first chamber; and a second fluid conduit fluidly connected to the second chamber. 
     According to yet another aspect of the present disclosure, an ablation system for ablating tissue in a living subject is provided. The ablation system includes an ablation electrode system including a needle electrode assembly. The needle electrode assembly includes an outer tube having at least a conductive distal tip and defining a cavity therein; and an inner tube disposed at least partially within the cavity of the outer tube and defining a lumen therein. 
     The ablation electrode system further includes a hub assembly fluidly connected to the needle electrode assembly. The hub assembly defines a first chamber and a second chamber; wherein a proximal end portion of the inner tube is in fluid communication with the first chamber and a proximal end portion of the outer tube is in fluid communication with the second chamber. 
     The ablation system includes a source of electrosurgical energy; a source of fluid; an electrical conduit electrically interconnecting the outer tube of the needle electrode assembly and the source of electrosurgical energy; a first fluid conduit fluidly interconnecting the source of fluid and the first chamber; and a second fluid conduit fluidly connected to the second chamber. 
     The present disclosure also relates to surgical device such as, for example, ablation electrode systems used for thermosurgery procedures and the like. 
     According to one aspect of the present disclosure, a surgical device for performing a surgical procedure on a patient is provided and includes a handle assembly including a housing having a distal end and a proximal end; a tissue engaging member supported in and extending from the distal end of the housing of the handle assembly; at least one conduit having a first end operatively associated with the tissue engaging member and a second end extending from the housing of the handle assembly; and a strain relief member supported on the at least one conduit and connected to the housing. The strain relief member and the housing are configured to enable poly-axial movement of the strain relief member with respect to the housing. 
     In an embodiment, the strain relief member and the housing may be connected to one another in a ball and socket arrangement. 
     In another embodiment, the housing may define a substantially spherical socket and the strain relief member may include at least a complimentary substantially spherical portion configured for reception in the socket of the housing. 
     In yet another embodiment, the strain relief member may include an annular rib extending at least partially around a circumference thereof and dimensioned to contact a surface of the housing. 
     In a further embodiment, the housing may define an aperture configured to receive the strain relief member, wherein the aperture defines an annular groove formed therein, and wherein the strain relief member may include an annular apron extending from a surface thereof and configured for disposition in the annular groove formed in the aperture of the housing. 
     In an embodiment, the housing may define an aperture configured to receive the strain relief member, and wherein the strain relief member may include an annular apron extending from a surface thereof and configured to extend beyond the aperture. 
     In yet another embodiment, the housing may define an aperture configured to receive the strain relief member, wherein the aperture may define at least one axial groove formed therein, and wherein the strain relief member may include an enlarged first and second body portion interconnected by a tapered portion. The strain relief member may include at least one axially extending rib configured to selectively engage each of the at least one axial grooves formed in the aperture of the housing upon a relative rotation of the strain relief member with respect to the housing. 
     The tissue engaging member may include at least one needle electrode assembly. Each needle electrode assembly may include an outer tube having at least a conductive distal tip, a proximal end portion supported in the housing and defining a cavity therein; and an inner tube disposed at least partially within the cavity of the outer tube and having a proximal end portion supported within the housing, the inner tube defining a lumen therethrough. The at least one conduit may include an electrical conduit electrically connected to the outer tube of each of the at least one needle electrode assemblies; a first fluid conduit fluidly connected to the inner tube of each of the at least one needle electrode assemblies; and a second fluid conduit fluidly connected to the outer tube of each of the at least one needle electrode assemblies. 
     The surgical device may further include a hub assembly supported within the housing of the handle assembly and fluidly connected to the needle electrode assembly. The hub assembly may include an outer shell defining a lumen therein; and an inner manifold operatively supported in the lumen of the outer shell, the inner manifold and the outer shell being configured and dimensioned so as to define a first chamber and a second chamber therebetween. The proximal end portion of the inner tube may be in fluid communication with the first chamber and the proximal end portion of the outer tube may be in fluid communication with the second chamber, wherein the first fluid conduit is connected to the first chamber and the second fluid conduit is connected to the second chamber. 
     The outer tube of the needle electrode assembly may be fabricated from an electrically conductive material. A layer of insulative material may be disposed on an outer surface of the outer tube and wherein the distal tip of the outer tip may be exposed. The inner tube may deliver fluid to the distal tip of the outer tube. 
     The surgical device may further include a thermocouple assembly electrically connected to the inner tube. The thermocouple assembly may include a constantan wire extending through the lumen of the inner tube and electrically connected to a distal end of the inner tube. 
     The inner manifold may define a lumen therein interconnecting the second chamber of the hub assembly to the second fluid conduit. 
     An adhesive may be applied to a proximal end of the inner manifold and the outer shell to at least one to secure the inner manifold within the outer shell and to seal the hub assembly from fluid leaks from between the outer shell and the inner manifold. A seal element may be provided between the outer shell and the inner manifold of the hub assembly to prevent transmission of fluid between the first chamber and the second chamber. 
     The surgical device may further include a plurality of needle electrode assemblies supported in and extending from the handle assembly. A proximal end portion of each inner tube may be in fluid communication with the first chamber and a proximal end portion of each outer tube may be in fluid communication with the second chamber. 
     According to another aspect of the present disclosure, an ablation electrode system for use with a source of electrosurgical energy to ablate tissue in a living subject is provided. The ablation electrode system includes a handle assembly including a housing; and at least one needle electrode assembly supported in and extending from the housing of the handle assembly. Each needle electrode assembly includes an outer tube having at least a conductive distal tip, a proximal end portion supported in the housing of the handle assembly, and defining a cavity therein; and an inner tube disposed at least partially within the cavity of the outer tube and having a proximal end portion supported within the housing of the handle assembly, the inner tube defining a lumen therein. The ablation electrode system further includes an electrical conduit electrically connected to the outer tube of each of the at least one needle electrode assemblies; a first fluid conduit fluidly connected to the inner tube of each of the at least one needle electrode assemblies; a second fluid conduit fluidly connected to the outer tube of each of the at least one needle electrode assemblies; and a strain relief member connected to the housing and having each of the conduits extending therethrough. The strain relief member and the housing are configured to enable poly-axial movement of the strain relief member with respect to the housing. 
     For a better understanding of the present invention and to show how it may be carried into effect, reference will be made by way of example to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, which constitute a part of the specification, exemplary embodiments exhibiting various objectives and features hereof are set forth, specifically: 
         FIG. 1  is a perspective view of an ablation electrode system in accordance with an embodiment of the present disclosure; 
         FIG. 2  is an enlarged perspective view of the ablation electrode system of  FIG. 1 , with a handle half-section removed therefrom and a hub assembly disposed therein shown partially broken away; 
         FIG. 3  is a longitudinal cross-sectional view of the ablation electrode system of  FIGS. 1 and 2 ; 
         FIG. 4  is an enlarged longitudinal cross-sectional view of the hub assembly of  FIGS. 2 and 3 ; 
         FIG. 5  is a longitudinal cross-sectional view of the outer shell of the hub assembly of  FIGS. 2-4 , including a needle electrode shown operative connected thereto; 
         FIG. 6  is a perspective view an inner manifold of the hub assembly of  FIGS. 2-4 ; 
         FIG. 7  is a longitudinal cross-sectional view of the inner manifold of  FIG. 6 ; 
         FIG. 8  is a perspective view of an ablation electrode system according to an alternate embodiment of the present disclosure; 
         FIG. 9  is a longitudinal cross-sectional view of the ablation electrode system of  FIG. 8 ; 
         FIG. 10  is a longitudinal cross-sectional view of the outer shell of the hub assembly of  FIG. 9 , including needle electrodes shown operative connected thereto; 
         FIG. 10A  is a distal end view of the outer shell of the hub assembly of the ablation electrode system of  FIG. 8 ; 
         FIG. 11  is a perspective view an inner manifold of the hub assembly of  FIG. 9 ; 
         FIG. 12  is a longitudinal cross-sectional view of the inner manifold of  FIG. 11 ; 
         FIG. 13  is a perspective view of an ablation electrode system illustrating a strain relief member operatively associated therewith for support of the cables and/or conduits entering the handle; 
         FIG. 14  is a schematic perspective view of a strain relief member for use with ablation electrode system; 
         FIG. 15  is a schematic longitudinal cross-sectional view of another strain relief member shown supported in the handle of the ablation electrode system; 
         FIG. 16  is a schematic longitudinal cross-sectional view of yet another strain relief member shown supported in the handle of the ablation electrode system; 
         FIG. 17  is a schematic perspective view of another strain relief member for use with ablation electrode system; and 
         FIG. 18  is a cross-sectional view of the strain relief member of  FIG. 17 , as taken through  18 - 18  of  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments of ablation electrode systems, in accordance with the present disclosure, will now be described in detail with reference to the drawings figures wherein like reference numerals identify similar or identical structural elements. As shown in the drawings and described throughout the following description, as is traditional when referring to relative positioning on a surgical instrument, device or apparatus, the term “proximal” refers to the end of the instrument, apparatus or device that is closer to the user and the term “distal” refers to the end of the apparatus that is further away from the user. 
     Referring initially to  FIGS. 1-7 , an electrode ablation system, according to an embodiment of the present disclosure, is generally designated as ablation system  100 . Ablation system  100  includes a housing or handle assembly  110 , and at least one needle electrode assembly  150  supported within and extending from housing assembly  110 . Housing assembly  110  and needle electrode assembly  150  define a central longitudinal axis “X”. 
     As seen in  FIGS. 1-3 , housing assembly  110  includes a housing or handle  112  having first half-section  112   a  and a second half-section  112   b  selectively connectable to one another (e.g., in a snap-fit manner) via connecting structure  114  or the like. In one embodiment, housing  112  has a substantially conical shape defining a flattened proximal surface  116   a  and a flattened distal surface  116   b  ( FIGS. 2 and 3 ). Housing  112  further includes an annular ramp-like structure  116   c  extending from the surface thereof. Ramp-like structure  116   c  acts as a surface against which an operators fingers contact for distal advancement of needle electrode  150  into the patient and/or proximal withdrawal of needle electrode  150  from the patient. 
     As seen in  FIGS. 2-8 , electrode ablation system  100  further includes a hub assembly  120  supported in housing  112  of housing assembly  110 . Hub assembly includes a hub assembly outer shell  130  and a hub assembly inner manifold  140  disposed within outer shell  130 . Outer shell  130  and inner manifold  140  of hub assembly are each fabricated from a suitable electrically non-conductive material. 
     As seen in  FIGS. 2-5 , hub assembly outer shell  130  includes a body portion  132  defining a central lumen  134  extending therethrough. Outer shell  130  defines a central longitudinal axis “X1” extending through central lumen  134 . In an embodiment, when outer shell  130  is positioned in housing  112 , the central longitudinal “X1” axis thereof at least substantially aligns with the central longitudinal “X” axis of housing  112  and needle electrode assembly  150 . Central lumen  134  of outer shell  130  includes a tapered distal end  136  defining a constricted passage  134   a  therethrough. Passage  134   a  is sized to support and receive needle electrode assembly  150  therein. 
     Body portion  132  of outer shell  130  may include an annular flange  138  formed therearound. As seen in  FIGS. 2 and 3 , annular flange  138  of outer shell  130  is receivable in a complementary annular channel or groove  118  formed or provided in housing  112 . Accordingly, annular flange  138  and annular groove  118  cooperate to fix the location of hub assembly  120  relative to housing  112 . 
     As seen in  FIGS. 2-4, 6 and 7 , inner manifold  140  is configured and dimensioned for support within lumen  134  of outer shell  130 . Inner manifold  140  includes a body portion  142  defining a first or inflow lumen  144   a  formed at least partially in a proximal end portion  142   b  thereof. Inner manifold  140  further includes a second or outflow lumen  144   b  extending entirely therethrough. Inner manifold  140  further includes a third lumen  144   c  formed at least partially in a distal end portion  142   a  thereof. 
     As seen in  FIGS. 3, 4, 6 and 7 , inner manifold  140  defines a first recess  148  formed therein such that when inner manifold  140  is inserted into lumen  134  of outer shell  130 , first recess  148  defines a first cavity or chamber  122  between outer shell  130  and inner manifold  140 . As seen in  FIGS. 3 and 4 , first lumen  144   a  and third lumen  144   c  are each in fluid communication with first chamber  122 . 
     With continued reference to  FIGS. 3 and 4 , when inner manifold  140  is inserted into lumen  134  of outer shell  130 , a second chamber  124  is defined in tapered distal end  136  of outer shell  130 . When inner manifold  140  is so positioned, second lumen  144   b  of manifold  140  is in fluid communication with the second chamber  124 . 
     As seen in  FIGS. 3, 4, 6 and 7 , body portion  142  of inner manifold  140  may include an annular groove  142   a  formed therein. As seen in  FIGS. 3 and 4 , annular groove  142   a  of body portion  142  of inner manifold  140  is configured and dimensioned to receive a complementary annular flange or rib  128  formed in body portion  132  of outer shell  130 . Accordingly, annular flange  128  and annular groove  142   c  cooperate to fix the location of inner manifold  140  relative to outer shell  130 . 
     In addition, as seen in  FIG. 4 , a glue “G,” including and not limited to, adhesives, epoxies, bonding agents, cements, silicones, and the like, is applied in a proximal or rear portion of lumen  134  of outer shell  130 , on a proximal or rear surface of inner manifold  140 , and at locations therebetween. Glue “G” functions to further secure inner manifold  140  within outer shell  130  and to create a seal between outer shell  130  and inner manifold  140  to thereby inhibit and/or prevent the escape of fluid from therebetween. 
     In an embodiment, as seen in  FIGS. 2-4 , hub assembly  120  includes a seal element  126  (e.g., an O-ring) disposed between body portion  132  of outer shell  130  and body portion  142  of inner manifold  140 . Seal element  126  functions to reduce and/or prevent fluid from traveling between first chamber  122  and second chamber  124 . 
     As seen in  FIGS. 1-4 , a first or in-flow conduit  10  is fluidly connected to first lumen  144   a  of inner manifold  140 . A distal end of first conduit  10  extends through housing  112  of housing assembly  110  and is frictionally inserted into first lumen  144   a  of inner manifold  140  of hub assembly  120 . 
     With continued reference to  FIGS. 1-4 , a second or out-flow conduit  20  is fluidly connected to second lumen  144   b  of inner manifold  140 . Desirably, a distal end of second conduit  20  extends through housing  112  of housing assembly  110  and is frictionally inserted into second lumen  144   b  of inner manifold  140  of hub assembly  120 . 
     Turning now to  FIGS. 1-5 , needle electrode assembly  150  is described in greater detail. Needle electrode assembly  150  includes an outer tube  152   a  having an exposed distal end portion  154   a  terminating in a sharpened distal tip  156   a  which is constructed so as to penetrate tissue with a minimum risk of hemorrhage from the puncture tract. Outer tube  152   a  is constructed from a suitable electrically conductive material. Outer tube  152   a  includes a proximal end portion  158   a  supported in housing  112 , and in an embodiment, in a distal lumen  134   b  formed in and extending distally from constricted passage  134   a  of outer shell  130 , as seen in  FIGS. 4 and 5 . Outer tube  152   a  is hollow and defines a cavity  160   a  therein. 
     In an embodiment, the non-exposed part of outer tube  152   a  may be surrounded by an insulating material. The insulating material may be any material which is biologically acceptable and suitable for insertion into tissue. Since distal end portion  154   a  is exposed or non-insulated, distal end portion  154   a  is capable of DC or AC delivery, preferably RF delivery. 
     Needle electrode assembly  150  further includes an inner tube  152   b  disposed substantially co-axially within cavity  160   a  of outer tube  152   a . Inner tube  152   b  includes a distal end portion  156   b  (see  FIGS. 6 and 7 ) located near distal end portion  154   a  of outer tube  152   a  and a proximal end portion  158   b  extending from proximal end portion  158   a  of outer tube  152   a . Proximal end portion  158   b  of inner tube  152   b  extends through constricted passage  134   a  and into or through third lumen  144   c  of inner manifold  140 . It is envisioned that proximal end portion  158   b  of inner tube  152   b  is in fluid communication with first cavity or chamber  122  defined between inner manifold  140  and outer shell  130 , see  FIGS. 2-4 . 
     In use, cooling fluid “F” is delivered to distal tip  156   a  of outer tube  152   a  from in-flow conduit  10 . In particular, cooling fluid “F” travels from in-flow conduit  10 , into first chamber  122 , into lumen  160   b  (see  FIGS. 6 and 7 ) of inner tube  152   b  of needle electrode assembly  150 , to distal tip  156   a  of outer tube  152   a . Cooling fluid “F” is led away from distal tip  156   a  of outer tube  152   a  through cavity  160   a , through second chamber  124 , through second lumen  144   b  of inner manifold  140 , and out through out-flow tube  20 . Cooling fluid “F” may be communicated to a collecting container (not shown) or back to a source of fluid “SF” (see  FIG. 1 ) for re-circulation. Circulation of cooling fluid “F” may be established with the use of a suitable pump (not explicitly shown). 
     As seen in  FIGS. 2, 3, 6 and 7 , electrode ablation system  100  further includes a first electrical conduit  170  extending through housing  112  and electrically connected to outer tube  152   a  of needle electrode assembly  150 . In particular, first electrical conduit  170  includes a distal end  170   a  electrically connected to outer tube  152   a  at a location distal of hub assembly  120  and within housing  112 . First electrical conduit  170  is also electrically connected to a source of electrosurgical energy “E”. Accordingly, electrosurgical energy may be delivered from the source of electrosurgical energy, through first electrical conduit  170 , to outer tube  152   a.    
     As seen in  FIGS. 2-4, 6 and 7 , electrode ablation system  100  further includes a thermocouple assembly  172  operatively associated with inner tube  152   b . Thermocouple assembly  172  includes a first wire or thermocouple  174  extending through lumen  160   b  of inner tube  152   b . A distal end  174   a  of first wire  174  is desirably electrically secured to distal end portion  156   b  of inner tube  152   b , as by, for example, soldering and the like. First wire  174  may be fabricated from constantan (i.e., a high-resistance alloy of approximately 40% nickel and 60% copper). However, other suitable materials may be used for first wire  174 , such as, for example, any suitable conductor that is dissimilar from inner tube  152   b  (e.g., stainless steel) such that a thermocouple is created between the two materials. 
     Thermocouple assembly  172  further includes a second wire  176  having a distal end  176   a  electrically connected to inner tube  152   b . In an embodiment, distal end  176   a  of second wire  176  is connected to a proximal end portion  158   b  of inner tube  152   b . Second wire  176  functions to electrically interconnect first wire  174  and a thermocouple measuring circuit. Accordingly, a temperature measurement signal from the thermocouple measuring circuit may then be sent to an electrosurgical energy source “E”, and/or a central processing unit for monitoring. 
     As seen in  FIGS. 1, 2 and 7 , each of electrical conduit  170 , first wire  174  and second wire  176  may be contained in a single cable  180 . 
     Turning now to  FIGS. 8-12 , an electrode ablation system, in accordance with another embodiment of the present disclosure, is generally designated as  200 . Electrode ablation system  200  is substantially similar to ablation system  100  and will be discussed in detail to the extent necessary to identify differences in construction and operation. Unlike electrode ablation system  100  which includes a single needle electrode assembly  150 , electrode ablation system  200  includes three needle electrode assemblies  250   a - 250   c  extending distally from housing  112  of housing assembly  110 . While a single and three needle electrode assemblies have been shown and described herein, any suitable number of needle electrode assemblies may be provided. 
     As seen in  FIGS. 9-12 , hub assembly  220  of electrode ablation system  200  includes a hub assembly outer shell  130  and a hub assembly inner manifold  240  operatively disposed within outer shell  230 . 
     As seen in  FIGS. 9, 10 and 10A , hub assembly outer shell  230  includes a body portion  232  defining a central lumen  234  extending therethrough. Desirably, outer shell  230  includes three constricted passages  236   a - 236   c  extending through a distal end portion  230   a  of outer shell  230  and in fluid communication with central lumen  234 . Desirably, each passage  236   a - 236   c  is sized to support and receive a proximal end of outer tube  252   a  of a respective needle electrode assembly  250   a - 250   c.    
     As seen in  FIGS. 9, 11 and 12 , inner manifold  240  is configured and dimensioned for support within lumen  234  of outer shell  230 . Inner manifold  240  includes a body portion  242  defining a first or inflow lumen  244   a  formed at least partially in a proximal end portion  242   b  thereof. Inner manifold  240  further includes a second or outflow lumen  244   b  extending entirely therethrough. Inner manifold  240  further includes a plurality of third lumens  244   c  formed at least partially in a distal end portion thereof  242   a . Each third lumen  244   c  of inner manifold  240  is configured and dimensioned to receive and support a proximal end of a respective inner tube  252   b  of needle electrode assemblies  250   a - 250   c  therein. 
     As seen in  FIGS. 9, 11 and 12 , inner manifold  240  defines a first recess  248  formed therein such that when inner manifold  240  is inserted into lumen  234  of outer shell  230 , first recess  248  defines a first cavity or chamber  222  between outer shell  230  and inner manifold  240 . As can be appreciated and similar to hub assembly  120  of electrode ablation system  100 , first lumen  244   a  and each third lumen  244   c  are in fluid communication with first chamber  222 . 
     With continued reference to  FIGS. 9, 11 and 12 , when inner manifold  240  is inserted into lumen  234  of outer shell  230 , a second chamber  224  is defined in distal end portion  236  of lumen  234  of outer shell  230 . When inner manifold  240  is so positioned, second lumen  244   b  of manifold  240  is in fluid communication with the second chamber  224 . 
     As seen in  FIGS. 9-12 , each needle electrode assembly  250   a - 250   c  of electrode ablation system  200  is substantially similar to needle electrode assembly  150  of electrode ablation system  100 , and therefore reference may be made to the detailed discussion of needle electrode assembly  150  for an understanding and description of needle electrode assemblies  250   a - 250   c.    
     Use of electrode ablation system  200  will now be described in detail. In use, cooling fluid “F” is delivered to a distal tip  256  of each outer tube  252   a . In particular, cooling fluid travels from in-flow conduit  10 , into first chamber  222 , into a lumen of an inner tube (see  FIGS. 6 and 7 ) of each needle electrode assembly  250   a - 250   c , to a distal tip  256  of the outer tube of each needle electrode assembly  250   a - 250   c . The cooling fluid is led away from distal tip  256  of the outer tube of each needle electrode assembly  250   a - 250   c , through second chamber  224 , through second lumen  244   b  of inner manifold  240 , and out through out-flow tube  20 . 
     As seen in  FIGS. 11 and 12 , a first wire  174  of thermocouple assembly  172  extends through lumen  160   b  (see  FIG. 6 ) of at least one inner tube  252   b  of needle electrode assemblies  250   a - 250   c . As mentioned above, a distal end  174   a  of first wire  174  is desirably electrically secured to a distal end portion of inner tube  252   b , as by, for example, soldering and the like. Desirably, first wire  174  is fabricated from constantan or the like (i.e., a high-resistance alloy of approximately 40% nickel and 60% copper). A second wire  176  of thermocouple assembly  172  has a distal end electrically connected to inner tube  252   b    
     The handle of needle electrode system  200  is configured and adapted so as to maintain needle electrode assemblies  250   a - 250   c  substantially parallel to one another during insertion and/or placement of needle electrode assemblies  250   a - 250   c  into a target surgical site. 
     Turning now to  FIGS. 13-18 , electrode ablation systems  100 ,  200  may each include an adjustable cord strain relief member  50  operatively disposed on cable  180 , in-flow conduit  10 , and/or out-flow conduit  20 . Strain relief member  50  is configured and dimensioned for operative engagement in an aperture  114  (see  FIGS. 1 and 2 ) of housing  112  of handle assembly  110 . In an embodiment, aperture  114  is formed in a side of housing  112  of handle assembly  110  such that cable  180 , in-flow conduit  10  and/or out-flow conduit  20  may extend out of the side thereof. By having cable  180 , in-flow conduit  10  and/or out-flow conduit  20  exit from a side of housing  112  of handle assembly  110  a strain relief for cable  180 , in-flow conduit  10  and/or out-flow conduit  20  is established. 
     Strain relief member  50  includes a body portion  52  having a substantially hour-glass configuration. Body portion  52  may include a first substantially spherical portion  52   a  and a second substantially spherical portion  52   b . Desirably, second portion  52   b  of body portion  52  is poly-axially supported (e.g., in the manner of a ball and socket joint) within a complementarily sized and shaped aperture  114 . 
     As seen in  FIGS. 14-16 , an annular rib  54   a  may be provided on the surface of second body portion  52   a  for engaging the inner surface of shaped aperture  114 . Strain relief member  50  may also be provided with a shield or apron  56  extending radially therefrom. Shield  56  may be disposed within an appropriately sized recess  116  formed in handle  112 , as seen in  FIG. 15 , or may be disposed externally of handle  112 , as seen in  FIG. 16 . 
     As seen in  FIGS. 17 and 18 , strain relief member  50  may include means for locking including a tapered portion  52   c  disposed between first body portion  52   a  and second body portion  52   b , and at least one longitudinally oriented locking rib  54   b  projecting from tapered portion  52   c . Locking rib  54   b  is configured and dimensioned to selectively engage complementary channels  118  formed in handle  112 . In use, as strain relief member  50  is moved in a first direction (as indicated by arrow “A”), locking rib  54   b  disengages channels  118  to unlock strain relief member  50 , and as strain relief member  50  is moved in a second direction (opposite to direction “A”), locking rib  54   b  engages channels  118  to lock strain relief member  50 . 
     The foregoing description is merely a disclosure of particular embodiments and is no way intended to limit the scope of the invention. Other possible modifications are apparent to those skilled in the art and all modifications are to be defined by the following claims.