Abstract:
Systems and methods for treating a tissue region employ an expandable structure projecting beyond the distal end of a catheter tube. A distal tail projects beyond the far end of the basket assembly. The distal tail includes a guidewire lumen that accommodates passage of a guidewire without threading the guidewire through the catheter tube.

Description:
RELATED APPLICATION  
       [0001]    This application claims the benefit of the filing date of copending provisional U.S. Patent Application Serial No. 60/278,738, filed Mar. 26, 2001, and entitled “Systems and Methods for Positioning and Stabilizing External Instruments Deployed within the Body.” 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention generally relates to systems and methods for inserting and securing the position of an external instrument, such as a catheter tube, in the body, e.g., through the oral cavity and into the esophagus for the treatment of gastric esophageal reflux disease (GERD).  
         BACKGROUND OF THE INVENTION  
         [0003]    Procedures requiring insertion of an external instrument into the body, e.g., through the oral cavity into the esophagus, are known. Bite blocks are typically used to hole the patient&#39;s mouth open during these procedures. During these procedures, it also may be necessary to locate the instrument in an intended position. It may also be necessary to stabilize the instrument in an intended position.  
           [0004]    There remains a need for simple, cost-effective ways to introduce an instrument through the oral cavity to locate the instrument and to selectively maintain the instrument in a fixed and stable position during a given medical procedure.  
         SUMMARY OF THE INVENTION  
         [0005]    The invention provides systems and methods for treating a tissue region. The systems and methods employ an expandable structure that projects beyond the distal end of a catheter tube. A distal tail projects beyond the far end of the basket assembly. The distal tail includes a guidewire lumen that accommodates passage of a guidewire without threading the guidewire through the catheter tube. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIGS. 1 a - a/a - b  is a side view of a bite block and five alternate embodiments of inserts carrying a centrally located gripping tool that may be employed with the bite block.  
         [0007]    [0007]FIG. 1 b  is a side view of a bite block and an embodiment of an insert carrying an eccentrically located gripping tool that may be employed with the bite block.  
         [0008]    [0008]FIG. 1 c  is a side view of a bite block and two alternate embodiments of “clip-on” inserts carrying eccentrically located gripping tools that may be employed with the bite block.  
         [0009]    [0009]FIG. 2 is a front view of a bite block incorporating an insert carrying a gripping tool with a cam mechanism.  
         [0010]    [0010]FIG. 3 a  is a schematic of a gripping tool showing the position of a gripping element and actuator mechanism in a closed position.  
         [0011]    [0011]FIG. 3 b  is a schematic of a gripping tool showing the position of a gripping element and actuator mechanism in an open position.  
         [0012]    [0012]FIG. 4 a  is a side view of one of the embodiments shown in FIGS. 1 a - a.    
         [0013]    [0013]FIGS. 4 b - 4   d  are front views illustrating the operation of the cam surfaces incorporated in the jaws of the insert shown in FIG. 4 a.    
         [0014]    [0014]FIG. 4 e  is a side view illustrating the open and closed positions of the jaws of the gripping tool shown in FIG. 4 a.    
         [0015]    [0015]FIG. 5 a  is a side view of an embodiment shown in FIGS. 1 a - a  that incorporates a cam mechanism.  
         [0016]    [0016]FIG. 5 b  is an exploded view of FIG. 5 a.    
         [0017]    [0017]FIG. 5 c  is a front view of the insert shown in FIG. 5 a.    
         [0018]    [0018]FIG. 5 d  is a side view of the insert shown in FIG. 5 a , illustrating the position of the cam mechanism in the open position.  
         [0019]    [0019]FIG. 5 e  is a front view of the insert shown in FIG. 5 a , illustrating the position of the jaws of the gripping tool in the open position.  
         [0020]    [0020]FIG. 5 f  is a side view of the insert shown in FIG. 5 a , illustrating the position of the jaws of the gripping tool in the open position.  
         [0021]    [0021]FIG. 5 g  is a side view of the insert shown in FIG. 5 a , illustrating the position of the cam mechanism in the closed position.  
         [0022]    [0022]FIG. 5 h  is a front view of the insert shown in FIG. 5 a , illustrating the position of the jaws of the gripping tool in the closed position.  
         [0023]    [0023]FIG. 5 i  is a side view of the insert shown in FIG. 5 a , illustrating the position of the jaws of the gripping tool in the open position.  
         [0024]    [0024]FIG. 6 a  is a side view of an embodiment shown in FIGS. 1 a - a  that incorporates a C-clamp mechanism.  
         [0025]    [0025]FIG. 6 b  is an exploded view of FIG. 6 a.    
         [0026]    [0026]FIG. 6 c  is a front view of the insert shown in FIG. 6 a.    
         [0027]    [0027]FIG. 6 d  is a front view of the insert shown in FIG. 6 a , illustrating the position of the jaws of the gripping tool in the closed position.  
         [0028]    [0028]FIG. 6 e  is a front view of the insert shown in FIG. 6 a , illustrating the use of the C-clamp and the position of the jaws of the gripping tool in the open position.  
         [0029]    [0029]FIG. 7 a  is a side view of an embodiment shown in FIGS. 1 a - b  that incorporates a prong-clamp mechanism.  
         [0030]    [0030]FIG. 7 b  is a breakaway view of FIG. 7 a.    
         [0031]    [0031]FIG. 7 c  is a front view of the insert shown in FIG. 7 a.    
         [0032]    [0032]FIG. 7 d  is a front view of the insert shown in FIG. 7 a , illustrating the position of the jaws of the gripping tool in the closed position.  
         [0033]    [0033]FIG. 7 e  is a front view of the insert shown in FIG. 7 a , illustrating the use of the prong clamp and the position of the jaws of the gripping tool in the open position.  
         [0034]    [0034]FIG. 8 a  is a side view of an embodiment shown in FIGS. 1 a - b  that incorporates a clothespin-clamp mechanism centrally located within the insert opening.  
         [0035]    [0035]FIG. 8 b  is a front view of the insert shown in FIG. 8 a.    
         [0036]    [0036]FIG. 8 c  is a front view of the insert shown in FIG. 8 a , illustrating the position of the jaws of the gripping tool in the closed position.  
         [0037]    [0037]FIG. 8 d - 8   f  are front views illustrating the insertion of an external instrument into a bite block utilizing the upturned edges incorporated in the jaws of the insert shown in FIG. 8 a.    
         [0038]    [0038]FIG. 8 g  is a front view of the insert shown in FIG. 8 a , illustrating the use of the clothespin-clamp and the position of the jaws of the gripping tool in the open position.  
         [0039]    [0039]FIG. 9 a  is a side view of an embodiment shown in FIG. 1 b  that incorporates a clothespin-clamp mechanism eccentrically located within the insert opening.  
         [0040]    [0040]FIG. 9 b  is a front view of the insert shown in FIG. 9 a.    
         [0041]    [0041]FIG. 10 a  is a side view of a bite block and an embodiment of a clip-type insert shown in FIG. 1 c  that may be employed with the bite block.  
         [0042]    [0042]FIG. 10 b  is a rear view of the insert shown in FIG. 10 a.    
         [0043]    [0043]FIG. 10 c  is a front view of a bite block incorporating the insert shown in FIG. 10 a .  
         [0044]    [0044]FIG. 10 d  is rear view of the bite block and incorporated insert shown in FIG. 10 c.    
         [0045]    [0045]FIG. 11 a  is a side view of a bite block and an embodiment of a clip-type insert shown in FIG. 11 c  that may be employed with the bite block.  
         [0046]    [0046]FIG. 11 b  is a rear view of the insert shown in FIG. 11 a.    
         [0047]    [0047]FIG. 11 c  is a front view of a bite block incorporating the insert shown in FIG. 11 a.    
         [0048]    [0048]FIG. 11 d  is rear view of the bite block and incorporated insert shown in FIG. 11 c.    
         [0049]    [0049]FIG. 12 is a front view of a bite block, showing the insertion of an external instrument through the opening of the bite block alongside a jaw assembly and illustrating the movement required to position the external instrument in the jaw assembly.  
         [0050]    [0050]FIG. 13 is a front view of a bite block as in FIG. 12, illustrating the positioning of the external instrument in the jaw assembly.  
         [0051]    [0051]FIG. 14 a  is a side view of a catheter commonly employed in the treatment of GERD, illustrating an expandable structure in a deflated position and a series of electrodes retracted.  
         [0052]    [0052]FIG. 14 b  is a side view of the catheter shown in FIG. 14 a , illustrating the expandable structure inflated and the series of electrodes extended.  
         [0053]    [0053]FIG. 15 a  is an enlarged side view of the distal tail of the expandable structure shown in FIGS. 14 a  and  14   b.    
         [0054]    [0054]FIG. 15 b  is a cutaway side view of the distal tail shown in FIG. 15 a , detailing the interior lumen within the tail.  
         [0055]    [0055]FIG. 16 a  is a side view of a guidewire being threaded through the distal tail.  
         [0056]    [0056]FIG. 16 b  is a cutaway view of the distal tail illustrating the threading of a guidewire through the interior lumen within the tail.  
         [0057]    [0057]FIG. 17 is a side view of an individual in a reclined position with a bite block carrying a gripping tool inserted in the individuals mouth.  
         [0058]    [0058]FIG. 18 is a side view of the employment of a guidewire through a bite block carrying a gripping tool and into the esophagus.  
         [0059]    [0059]FIG. 19 is a side view of the employment of an endoscope through the bite block carrying a gripping tool and into the esophagus.  
         [0060]    [0060]FIG. 20 is a side view illustrating the threading of an employed guidewire through a catheter tip.  
         [0061]    [0061]FIG. 21 a  is a side view illustrating the final positions of the guidewire and the catheter after employment.  
         [0062]    [0062]FIG. 21 b  is an enlarged side view of the lower esophagus and stomach showing the final positions of the guidewire and the catheter after employment.  
         [0063]    [0063]FIG. 22 is a side view of the jaws of the gripping tool being moved to a closed position by manipulation of a cam mechanism.  
         [0064]    [0064]FIG. 23 is a side view illustrating the employed catheter with the expandable structure in an inflated position.  
         [0065]    [0065]FIG. 24 is a side view illustrating the employed catheter with the expandable structure inflated and the electrodes in an extended position.  
         [0066]    [0066]FIG. 25 is a side view of the jaws of the gripping tool being moved to an open position by manipulation of a cam mechanism, with the expandable structure deflated and the electrodes retracted.  
         [0067]    [0067]FIG. 26 is a side view of the employed catheter being rotated axially, with the expandable structure deflated and the electrodes retracted.  
         [0068]    [0068]FIG. 27 a  is a schematic of a lesion pattern after one ablation sequence is completed.  
         [0069]    [0069]FIG. 27 b  is a schematic of a lesion pattern after a second ablation sequence is performed following a 45° rotation of the catheter.  
         [0070]    [0070]FIG. 28 is a side view of the employed catheter being advanced axially, with the expandable structure deflated and the electrodes retracted.  
         [0071]    [0071]FIG. 29 is a schematic of a lesion pattern after two ablation sequences separated by 45° are performed at each of four levels.  
         [0072]    [0072]FIG. 30 is a side view showing the positioning of a catheter within the cardia of the stomach.  
         [0073]    [0073]FIG. 31 a  is a schematic of a lesion pattern after one ablation sequence.  
         [0074]    [0074]FIG. 31 b  is a schematic of a lesion pattern after a second ablation sequence is performed following a 22.5° rotation of the catheter.  
         [0075]    [0075]FIG. 31 c  is a schematic of a lesion pattern after a third ablation sequence is performed following a 22° rotation of the catheter in the opposite direction.  
         [0076]    [0076]FIG. 32 is a schematic of a lesion pattern after three ablation sequences separated by 22.5° are performed at each of two levels.  
         [0077]    [0077]FIG. 33 is a side view of a catheter commonly employed in the treatment of GERD, illustrating an expandable structure comprising an array of tubular spines, one of which accommodates passage of a guidewire.  
         [0078]    [0078]FIG. 34 is a cross-section view of one of the spines of the expandable structure illustrated in FIG. 33, detailing the interior of the three lumens that make up the spine.  
         [0079]    [0079]FIG. 35 is a schematic of the exterior surface of a section of the spine shown in FIG. 34, illustrating the positioning of openings within the lumens and electrode and temperature sensing elements carried within the lumens.  
         [0080]    [0080]FIG. 36 a  shows an exterior surface of the spine of the expandable structure illustrated in FIG. 33 that accommodates passage of a guidewire.  
         [0081]    [0081]FIG. 36 b  illustrates the interior surface of the spine shown in FIG. 36 a.    
         [0082]    [0082]FIG. 37 is an exploded view of the expandable structure carried at the distal region of the catheter shown in FIG. 33, illustrating the guidewire lumen carried by a spine and a two-piece distal guide assembly.  
         [0083]    [0083]FIG. 38 is a cross-section view of the inner sheath taken generally along line  38 - 38  in FIG. 37.  
         [0084]    [0084]FIG. 39 is a partially assembled side view of the expandable structure shown in FIG. 37, illustrating the attachment of the inner sheath and the coupling of an expandable body to the inner sheath.  
         [0085]    [0085]FIG. 40 is a fully assembled side view of the expandable structure shown in FIG. 39, illustrating the placement of the outer and inner sheath of the guide assembly and depicting a guidewire thread through the distal guide assembly and guidewire lumen. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0086]    I. THE BITE BLOCK  
         [0087]    [0087]FIGS. 1 a - a / 1   a - b  shows a bite block  10 . A bite block  10  is commonly used to hold an individual&#39;s mouth open during insertion of an instrument into the oral cavity. For example (see FIG. 21 a ), a bite block  10  can be utilized during procedures requiring insertion of a catheter tube  19  through the oral cavity into the esophagus  84 , such as in the treatment of gastroesophageal reflux disease (GERD).  
         [0088]    The bite block  10  may be conventional, formed, e.g., from hard, medical grade plastic by conventional molding techniques.  
         [0089]    Conventional bite blocks  10  comprise an opening  11  for insertion of an external instrument  15  (as shown in phantom lines in FIG. 1 a ). Typically, the opening  11  is large enough to readily accommodate insertion of a variety of differently sized and shaped instruments and is therefore not capable of holding an instrument in a fixed or stabilized position.  
         [0090]    As a result, insertion of an instrument  15  through the bite block  10  does not automatically result in the instrument  15  being held in the proper position. Correct positioning of the instrument  15  is generally useful to effective performance of a procedure.  
         [0091]    It is therefore necessary for an individual performing a procedure (or an assistant) to hold the instrument  15  in the proper position, often for extended periods of time. This can be both cumbersome and difficult to do.  
         [0092]    One aspect of the invention provides for a gripping tool (T) for association with a bite block  10 . Eight embodiments of a gripping tool (T 1 -T 8 ) are shown in FIGS. 1 a - a / 1   a - b ,  1   b , and  1   c . Five of the embodiments (T 1 -T 5 ) are shown in FIGS. 1 a - a / 1   a - b . Another embodiment (T 6 ) is shown in FIG. 1 b . Two additional embodiments (T 7  and T 8 ) are shown in FIG. 1 c.    
         [0093]    The gripping tool (T) holds an instrument  15  in a fixed or stabilized position within the oral cavity during a procedure and permits removal of the instrument upon completion of the procedure, as will be described in greater detail later. It further permits the moving of the instrument  15  from one fixed position to an alternate fixed position, as will also be described in greater detail later.  
         [0094]    Thus, the invention permits the hands of the provider to be freed during the procedure and assures that the instrument  15  will not inadvertently be moved during the procedure.  
         [0095]    The gripping tool (T) or any portion of it may be integral with the body of the bite block  10 . Alternately, the gripping tool (T) or any portion of it may be part of an insert  12  that is selectively attachable within the opening  11  of the bite block  10  at the instant of use.  
         [0096]    [0096]FIGS. 1 a - a / 1   a - b ,  1   b , and  1   c  show eight representative embodiments of gripping tools, T 1  to T 8 , each taking the form of an insert  12  insertable into the bite block opening  11 . FIG. 2 shows a bite block  10  carrying one embodiment of the gripping tool (T 2 ) after insertion into the bite block  10 .  
         [0097]    In any one of the embodiments of the gripping tool, T 1  to T 8  shown in FIGS. 1 a - a / 1   a - b ,  1   b , and  1   c , the inserts  12  may be formed, e.g., from hard, medical grade plastic by conventional molding techniques.  
         [0098]    In the illustrated embodiments T 1 -T 6 , the insert  12  is a generally cylindrical hollow body constructed to couple to the bite block  10  upon insertion. As shown in FIGS. 1 a - a / 1   a - b  and  1   b , in the illustrated embodiments T 1 -T 6 , the insert  12  comprises at least three features that serve to secure and guide the insert into the proper position within the bite block opening  11 .  
         [0099]    First, as shown in FIG. 1 a - a / 1   a - b , the insert  12  includes a top vane  14  and a bottom vane  23  that extend the length of the insert  12 . The vanes  14  and  23  are tapered so as to secure the insert  12  in proper position within the bite block  10  by making friction fit engagement against the interior wall of the bite block opening  11 .  
         [0100]    Alternately, as shown in FIG. 1 b , a second top vane  14  and a second bottom vane  23  may be provided.  
         [0101]    Second, the insert  12  includes a stoprest  13  to prevent over insertion of the gripping tool (T). The stoprest  13  is a straight perpendicular extension of the front edge of any of the vanes  14  or  23 .  
         [0102]    In the embodiments T 1  to T 5  shown in FIG. 1 a - a / 1   a - b , the stoprest  13  is located on the top vane  14 . In the embodiment T 6  shown in FIG. 1 b , the stoprests  13  are located on both top vanes  14  and bottom vanes  23 . of course, any number of vanes  14  and  23  and stoprests  13  can be provided.  
         [0103]    Third, to further secure the insert  12  properly within the bite block opening  11 , the insert  12  also includes first and second lips  16  on opposing sides of the insert  12 . The lips  16  have a plastic memory so as to engage the rear edge of the bite block  10  in a snap fit when the insert  12  is properly positioned within the bite block opening  11 .  
         [0104]    In alternate embodiments T 7  and T 8  (see FIG. 1 c ), an alternate insert  12 ′ is provided that incorporates a “clip-on” type mechanism constructed to couple to the bite block  10  upon insertion. FIGS. 10 c - 10   d  illustrate a bite block  10  carrying one embodiment (T 7 ) of the clip-on insert  12 ′ after insertion into the bite block  10 .  
         [0105]    [0105]FIGS. 11 c  and  11   d  illustrate a bite block  10  carrying another embodiment (T 8 ) of the clip-on insert  12 ′ after insertion into the bite block  10 .  
         [0106]    In the illustrated embodiments T 7 -T 8 , as shown in FIGS. 10 a - 10   d  and  11   a - 11   d , the insert  12 ′ comprises at least three features that serve to secure and guide the insert  12 ′ into the proper position within the bite block opening  11 .  
         [0107]    First, as shown in FIGS. 11 a  and  11   b , the insert  12 ′ is a member having a “folded” or “curved” shape whereby the insert  12 ′ is adapted to slide over the wall of the bite block  10  on either the right or left side of the opening  11 . In this arrangement, the “fold” or curve” results in the insert  12 ′ having a first side  94  and a second side  96 .  
         [0108]    The first side  94  of the insert  12 ′ is adapted to be positioned in the interior of the opening  11  and rest against the bite block  10  wall when the insert  12 ′ is positioned within the bite block  10  (see FIGS. 11 c  and  11   d ). The first side  94  carries a jaw assembly  18 . The second side  96  is adapted to be positioned exterior to opening  11  and rest against the bite block  10  wall when the insert  12  is positioned within the bite block  10 .  
         [0109]    Second, the insert  12 ′ is curved to prevent rotation within the bite block  10 . In the embodiments illustrated in FIGS. 10 a - 10   d  and  11   a - 11   d , the opening  11  is generally oval shaped. The insert  12 ′ is shaped so as to match the curvature of the bite block  10  on the right or left side of the bite block  10 , but not necessarily the top or bottom of the bite block  10 .  
         [0110]    This arrangement results in the gripping tool (T) having an eccentric location (see FIGS. 10 c  and  11   c ). The eccentric location provides a larger area in which to insert the external instrument  15  before positioning it within the gripping tool (T). The insertion of an external instrument  15  within a bite block  10  carrying an eccentrically located gripping tool (T) is illustrated in FIGS. 12 and 13.  
         [0111]    As shown in FIG. 12, an external instrument  15  is inserted within the bite block opening  11 . As indicated by arrows in FIG. 12, the external instrument  15  can then moved laterally to position it within the gripping tool (T).  
         [0112]    [0112]FIG. 13 illustrates the external instrument  15  positioned within the gripping tool (T).  
         [0113]    Third, the insert  12 ′ contains opposed grasping clasps positioned on opposite interior and exterior sides of the bite block  10  wall. Of course, the construction and number of grasping clasps can vary.  
         [0114]    In the embodiment illustrated in FIGS. 10 a  and  10   b , two outer grasping clasps  98  are spaced parallel to each other and positioned to be on one side of the bite block  10  wall when the insert  12 ′ is positioned within the bite block  10 . An inner clasp  100  is positioned (desirably equidistant) between the outer clasps  98  and positioned to be on the opposite side of the bite block  10  wall from the outer clasps  98  when the insert  12 ′ is positioned within the bite block  10 .  
         [0115]    Each of the clasps  98  and  100  has a foot-like appendage  102  extending perpendicularly from the end of the clasps  98  and  100 . The foot-like appendages  102  are capable of abutting against the back wall of bite block  10  when the insert  12 ′ is positioned within the bite block  10 , such that they provide a snap fit when the insert  12 ′ is positioned within the bite block  10 .  
         [0116]    Regardless of the particular structure, the purposes of the gripping tool (T) are to accommodate passage of an external instrument  15  through the bite block  10  and to grip the external instrument  15 .  
         [0117]    To this end, as illustrated in FIGS. 3 a  and  3   b , the gripping tool (T) comprises gripping elements  17  that are selectively movable and capable of pivoting between an open position (P 1 ) (see FIG. 3 b ) and a closed position (P 2 ) (see FIG. 3 a ), such that the distance between the elements  17  is greater in P 1  than in P 2 . An actuator mechanism  21  effectuates movement of the elements between P 1  and P 2 .  
         [0118]    P 1  (shown in FIG. 3 b ) is an open spaced-apart position corresponding to a first distance (D 1 ) between the gripping elements  17 . P 2  (shown in FIG. 3 a ) is a closed adjacently-spaced position corresponding to a second distance (D 2 ) between the gripping elements  17 , such that D 2  is less than D 1 .  
         [0119]    As FIG. 3 b  shows, in P 1  the gripping tool (T) accommodates passage of an external instrument  15  through the bite block  10 . As FIG. 3 a  shows, in P 2  the gripping tool (T) contacts the periphery of the external instrument  15 , thereby maintaining the instrument  15  in a fixed position within the bite block  10 .  
         [0120]    As FIGS. 1 a - a / 1   a - b ,  1   b , and  1   c  demonstrate, and as has already generally been discussed, the gripping tool (T) may take a variety of embodiments, eight of which (T 1  to T 8 ) are shown in FIGS. 1 a - a / 1   a - b ,  1   b , and  1   c . Other embodiments, of course, are possible.  
         [0121]    A. Bite Block Embodiment T 1   
         [0122]    [0122]FIGS. 4 a -  4   e  detail one of the embodiments (T 1 ) shown in FIG. 1 a  and its use. In the embodiment illustrated in FIG. 4 a , the gripping element  17  consists of a jaw assembly  18  carried by the insert  12 . The jaw assembly  18  comprises a first jaw  40  and a second jaw  42 . The jaws  40  and  42  extend from the insert  12  at parallel and oppositely spaced locations, thus having interior facing surfaces and exterior non-facing surfaces relative to each other.  
         [0123]    In the illustrated embodiment, resilient plastic memory biases the jaws  40  and  42  toward the closed position P 2 . The relative positions of the jaws  40  and  42  in Pi (phantom lines) and P 2  (solid lines) are illustrated in FIG. 4 e.    
         [0124]    As shown in FIGS. 4 a - 4   d , each of the jaws  40  and  42  includes a first indented cam surface  20  and a pair of second raised cam surfaces  22  on each jaw  40  and  42  flanking the indented cam surface  20 .  
         [0125]    The first cam surface  20  comprises an area of reduced thickness in the wall of the jaws  40  and  42 . The first cam surfaces  20  are normally oppositely spaced at the second distance D 2 , as FIG. 4 d  shows, to normally grip the instrument  15  confined between the jaws  40  and  42 , corresponding to position P 2 .  
         [0126]    The second cam surfaces  22  comprise areas of greater thickness in the walls of the jaws  40  and  42 .  
         [0127]    As FIG. 4 c  shows, manipulation of an external instrument  15  between an opposing pair of second cam surfaces  22  causes the jaws  40  and  42  to yield and open. The first cam surfaces  20  are moved to the first distance Dl, corresponding to position P 1 , thereby allowing the external instrument  15  to be inserted between the jaws  40  and  42  and removed from the jaws  40  and  42 .  
         [0128]    In this embodiment, the jaws  40  and  42  are formed to include the resilient plastic memory that, together with the cam surfaces  20  and  22 , provides the actuator mechanism  21  for the jaws  40  and  42 . The combination of the plastic memory and the cam surfaces  20  and  22  enables the jaws  40  and  42  to be moved so as to pivot selectively between P 1  and P 2 .  
         [0129]    More particularly, the resilient plastic memory yields in response to contact between the instrument  15  and the second cam surfaces  22  to allow the external instrument  15  to be inserted between the jaws  40  and  42  (position P 1  to P 2 ) and, likewise, to be removed from the jaws  40  and  42  (position P 2  to P 1 ).  
         [0130]    In the closed position, the jaws  40  and  42  are capable of holding an external instrument  15  in a fixed position. In the open position, the jaws  40  and  42  are positioned such that the external instrument  15  is not held in a fixed position, allowing it to be inserted or removed.  
         [0131]    In the illustrated embodiment, the jaws  40  and  42  are carried by an insert  12 . Alternately, the jaws  40  and  42  may be integral with a bite block  10 .  
         [0132]    B. Bite Block Embodiment T 2   
         [0133]    [0133]FIGS. 5 a - 5   i  detail a second embodiment (T 2 ) of the gripping tool shown in FIG. 1 a  and its use. In the embodiment illustrated in FIG. 5 a , the gripping element  17  consists of a jaw assembly  18 . The jaw assembly  18  comprises a first jaw  40  and a second jaw  42  carried by the insert  12 . The jaws  40  and  42  are similar to the jaws  40  and  42  in FIGS. 4 a - 4   e , but need not contain first cam surfaces  20  or second cam surfaces  22 .  
         [0134]    In this embodiment, the actuator mechanism  21  includes a resilient plastic memory in the jaws  40  and  42  and a cam mechanism  24  coupled to the jaws  40  and  42 . In the illustrated embodiment, this resilient memory biases the jaws  40  and  42  toward the P 1 , or open position shown in FIGS. 5 d - 5   f . Engagement of a series of cam regions on the control knob  26  by manipulation of the cam mechanism  24  overcomes this bias and moves the jaws  40  and  42  from the open (P 1 ) position to the closed (P 2 ) position, shown in FIGS. 5 g - 5   i.    
         [0135]    Alternately, the resilient memory can bias the jaws  40  and  42  in the P 2 , or closed, position. In yet another alternate embodiment, the jaws  40  and  42  need not be biased in either position.  
         [0136]    A variety of cam mechanisms  24  can be utilized. The cam mechanism  24  can be conventional, formed, e.g., from hard, medical grade plastic by conventional molding techniques.  
         [0137]    [0137]FIG. 5 b  illustrates an embodiment in which the cam mechanism  24  includes a control knob  26  and a pair of control appendages  28 . As FIG. 5 a  shows, the control appendages  28  are connected to the jaws  40  and  42  and engage the control knob  26 . The control knob  26  rotates on the appendages  28 .  
         [0138]    Each jaw  40  and  42  includes a control appendage  28  that extends from the respective jaw  40  or  42  in a perpendicular direction, as best illustrated in FIGS. 5 b - 5   c . Rotation of the control knob  26  exerts force on the control appendages  28  and thereby opens and closes the jaws  40  and  42  (i.e., moves the jaws  40  and  42  selectively between P 1  and P 2 ).  
         [0139]    In the illustrated embodiment (see FIG. 5 b ), the control knob  26  takes a ring form having an interior surface and an exterior surface. The interior surface includes a pair of diametrically opposed first cam regions  30 . A pair of diametrically opposed second cam regions  32  are oppositely spaced in the interior surface at a decreased diameter relative to the first cam regions  30 .  
         [0140]    The control appendages  28  rest within the interior surface of the control knob  26  in contact with either the first cam regions  30  or the second cam regions  32 . Rotation of the control knob  26  in a first direction (counterclockwise as shown by arrow in FIG. 5 d ), brings the first cam regions  30  into contact with the appendages  28 .  
         [0141]    When the appendages  28  rest in contact with the first cam regions  30 , the jaws  40  and  42  assume their normally biased open spaced-apart position (P 1 ), corresponding to a first distance (D 1 ) between the jaws  40  and  42 . The position of the cam in the P 1  position is shown in FIG. 5 d . The corresponding positioning of the jaws  40  and  42  in the P 1  position is shown in FIGS. 5 e - 5   f.    
         [0142]    In the open position (see FIGS. 5 e  and  5   f ), the jaws  40  and  42  are positioned such that the external instrument  15  is not held in a fixed position, allowing it to be inserted or removed.  
         [0143]    Rotation of the control knob  26  in a second direction (clockwise as shown by arrow in FIG. 5 g ) brings the second cam regions  32  into contact with the appendages  28 .  
         [0144]    When the control appendages  28  rest in contact with the second cam regions  32 , the jaws  40  and  42  are moved against the biasing force into the closed adjacently-spaced position (P 2 ), corresponding to a second distance (D 2 ) between the jaws  40  and  42 , such that D 2  is less than D 1 . The position of the cam in the P 2  position is shown in FIG. 5 g . The corresponding positioning of the jaws  40  and  42  in the P 2  position is shown in FIGS. 5 h - 5   n.    
         [0145]    In the closed position (see FIGS. 5 h  and  5   i ), the jaws  40  and  42  are capable of holding an external instrument  15  in a fixed position.  
         [0146]    As best illustrated in FIG. 5 b , the control knob  26  desirably includes first and second grasping extensions  34  to aid in the rotation of the control knob  26  circumferentially upon the appendages  28 .  
         [0147]    A first and second stopguard  36  (see FIG. 5 b ) are also desirably provided. The stopguards  36  prevent over-rotation of the control knob  26  in the first and second directions.  
         [0148]    Rotation thus permits the control knob  26  to move selectively between P 1 , in which the control appendages  28  contact the first cam regions  30 , and P 2 , in which the control appendages  28  contact the second cam regions  32 , thus permitting the jaws  40  and  42  to pivot between the D 1  and D 2  positions. In P 2 , the first stopguard  36  rests against the first control appendage  28  and the second stopguard  36  rests against the second control appendage  28 .  
         [0149]    In P 1 , the first stopguard  36  does not contact the first control appendage  28  and the second stopguard  36  does not contact the second control appendage  28 . However, further rotation in the first direction beyond Pi is prevented by contact between the stopguards  36  and their opposing control appendage  28 .  
         [0150]    In the illustrated embodiment, the cam mechanism  24  and jaws  40  and  42  are carried by an insert  12  for a bite block  10 . Alternately, the cam mechanism  24 , the jaws  40  and  42 , or both may be integral with the bite block  10 .  
         [0151]    C. Bite Block Embodiment T 3   
         [0152]    [0152]FIGS. 6 a - 6   e  detail another embodiment (T 3 ) shown in FIG. 1 a  and its use. In the embodiment illustrated in FIG. 6 a , the gripping element  17  takes the form of jaw assembly  18  comprising a “C-clamp”  38  carried by the insert  12 .  
         [0153]    As FIGS. 6 a - 6   c  best show, this C-clamp  38  includes levers comprising a first jaw  40 ′, a second jaw  42 ′, and a third jaw  44 . The jaws  40 ′,  42 ′, and  44  each include a first region  45  and second region  47 .  
         [0154]    The first region  45  is generally semi-circle-shaped. The second region  47  is a straight appendage extending from the end of the first region  45  and serves as a grasping appendage.  
         [0155]    The third jaw  44  is a mirror image of the first jaw  40 ′ and the second jaw  42 ′ also having a first region  45  and a second region  47 .  
         [0156]    As shown in FIG. 6 b , the C-clamp  38  also comprises a post  94  extending from the top of the front surface of the insert  12 . The post  94  extends through corresponding points on the first region  45  of each jaw  40 ′,  42 ′, and  44 . Thus, the post  94  serves as an axis upon which the jaws  40 ′,  42 ′, and  44  are attached in a hinged fashion such that they may pivot selectively along the axis of the post  94 .  
         [0157]    The first jaw  40 ′ is positioned proximal to the front surface of the insert  12  along the axis of the post  94 . The third jaw  44  is positioned medially along the axis of the post  94 . The second jaw  42 ′ is positioned distally along the axis of the post.  
         [0158]    The hinged arrangement permits the jaws  40 ′,  42 ′, and  44  to pivot between a first position (P 1 ) (see FIG. 6 e ) and a second position (P 2 ) (see FIG. 6 d ).  
         [0159]    In P 1 , the second region  47  of the third jaw  44  is aligned with the second regions  47  of the first jaw  40 ′ and the second jaw  42 ′ . In this position, the three first regions  45  form an opening of a first diameter (D 1 ). This corresponds to an open position, in which an external instrument  15  is not able to be held in a fixed position.  
         [0160]    In P 2 , the second region  47  of the third jaw  44  is spaced apart from the second regions  47  of the first jaw  40 ′ and the second jaw  42 ′. In this position, the first regions  45  of the three jaws form an opening of a second diameter (D 2 ) , such that D 2  is less than D 1 . This corresponds to a closed position, in which an external instrument  15  can be held in a fixed position.  
         [0161]    The hinge mechanism provides a resilient plastic memory and serves as an actuator mechanism  21  that enables the jaws  40 ′,  42 ′, and  44  to be moved so as to pivot selectively between P 1  and P 2 . This resilient memory biases the jaws  40 ′,  42 ′, and  44  toward the closed position P 2  (see FIG. 6 d ). Application of “squeezing” pressure (illustrated by arrows in FIG. 6 e ) on the second regions of the jaws  40 ′,  42 ′, and  44  overcomes this bias and moves the jaws  40 ′,  42 ′, and  44  from the closed (P 2 ) position to the open (P 1 ) position.  
         [0162]    The C-clamp  38  may be conventional, formed, e.g., from hard, medical grade plastic by conventional molding techniques.  
         [0163]    In the illustrated embodiment, the C-clamp  38  is carried by an insert  12  for a bite block  10 . Alternately, the C-clamp  38  or any portion of it may be integral with the bite block  10 .  
         [0164]    D. Bite Block Embodiment T 4   
         [0165]    [0165]FIGS. 7 a - 7   e  detail another embodiment (T 4 ) shown in FIG. 1 a  and its use. In the embodiment illustrated in FIG. 7 a , the gripping element  17  takes the form of jaw assembly  18  comprising a “prong-clamp” carried by the insert  12 .  
         [0166]    As FIGS. 7 a - 7   c  show, this prong-clamp  38  comprises a first jaw  40  and a second jaw  42 . The jaws  40  and  42  are similar to the jaws  40  and  42  in FIGS. 4 a - 4   e , but need not contain first cam surfaces  20  or second cam surfaces  22 .  
         [0167]    As shown in FIG. 7 a , this prong-clamp  46  also includes levers comprising a first prong  52 , a second prong  54 , and a third prong  56 .  
         [0168]    As also shown in FIG. 7 a , the first prong  52  and second prong  54  are integral with the first jaw  40 . The prongs consist of a first section  48  and a second section  50 . The first section  48  extends perpendicularly from the first jaw  40  at a right angle. The second section  50  extends perpendicularly from the first section  48  at a right angle from the first section  48 .  
         [0169]    The first prong  52  and second prong  54  are spaced apart along the first jaw  40  and positioned such that they are parallel to each other.  
         [0170]    As shown in FIG. 7 b , the third prong  56  is integral with the second jaw  42  and is spaced (desirably equidistant) between the first prong  52  and the second prong  54 . The third prong  56  consists of a first section  48  and a second section  50  and is essentially a mirror image of the first prong  52  and second prong  54 .  
         [0171]    That is, the first section  48  extends perpendicularly from the second jaw  42  at a right angle. The second section  50  extends perpendicularly from the first section  48  at a right angle from the first section  48  and serves as a grasping appendage.  
         [0172]    The jaws  40  and  42  possess a resilient plastic memory that serves as an actuator mechanism  21  that enables the jaws  40  and  42  to be moved so as to pivot selectively between P 1  and P 2 .  
         [0173]    In the open (P 1 ) position, illustrated in FIG. 7 e , the second section  50  of the third prong  56  is aligned with the second sections  50  of the first prong and the second prong  54 . In this position, the three prongs impart a correspondingly spaced-apart relation to the jaws  40  and  42  corresponding to a first diameter (D 1 ). This corresponds to an open position, in which an external instrument  15  is not able to be held in a fixed position.  
         [0174]    In P 2 , illustrated in FIG. 7 d , the second section  50  of the third prong  56  is spaced apart from the second sections  50  of the first prong  52  and the second prong  54 . In this position, the three prongs impart a correspondingly spaced-apart relation to the jaws  40  and  42  corresponding to a second diameter (D 2 ), such that D 2  is less than D 1 . This corresponds to a closed position, in which an external instrument  15  can be held in a fixed position.  
         [0175]    The resilient plastic memory biases the jaws  40  and  42  toward the closed, or P 2  position. Application of “squeezing” pressure (illustrated by arrows in FIG. 7 e ) on the second sections  50  of the prongs  52 ,  54 , and  56  overcomes this bias and moves the jaws  40  and  42  from the closed (P 2 ) position to the open (P 1 ) position.  
         [0176]    The prong clamp  46  may be conventional, formed, e.g., from hard, medical grade plastic by conventional molding techniques.  
         [0177]    In the illustrated embodiment, the prong-clamp  46  and jaws  40  and  42  are carried by an insert  12  for a bite block  10 . Alternately, the prong-clamp  46  or any portion of it, the jaws  40  and  42 , or any combination thereof may be integral with the bite block  10 .  
         [0178]    E. Bite Block Embodiment T 5   
         [0179]    [0179]FIGS. 8 a - 8   g  detail another embodiment (T 5 ) shown in FIG. 1 a  and its use. In the embodiment illustrated in FIG. 8 a , the gripping element  17  takes the form of a jaw assembly  18  comprising a “clothespin-type clamp”  104  carried by the insert  12 .  
         [0180]    As illustrated in FIGS. 8 a - 8   g , this clothespin-clamp  104  comprises a C-shaped groove  106 . The top side of the groove  106  comprises a first jaw  40  having an upturned edge  108 . The bottom side of groove  106  comprises a second jaw  42  having a downturned edge  110 . The upturned end downturned edges  108  and  110  serve as leading edges that guide the insertion of an external instrument  15  into the groove  104 .  
         [0181]    As shown in FIGS. 8 a - 8   g , this clothespin-clamp  104  also includes a first arm  112  integral with and extending horizontally from the top of the C-shape and a second arm  114  integral with and extending horizontally from the bottom of the C-shape, positioned such that the first arm and second arms  112  and  114  are parallel to each other.  
         [0182]    The jaws  40  and  42  possess a resilient plastic memory that, together with the upturned and downturned edges  106  and  108  and the first and second arms  112 , serve as an actuator mechanism  21  that enables the jaws  40  and  42  to moved so as to pivot selectively between P 1  and P 2 .  
         [0183]    This resilient plastic memory biases the jaws  40  and  42  toward the closed position P 2  (shown in FIG. 8 c ).  
         [0184]    As illustrated in FIGS. 8 d - 8   f , the resilient plastic memory yields in response to contact between the instrument  15  and the edges  108  and  110  to move the jaws  40  and  42  from the closed (P 2 ) position to the open (P 1 ) position.  
         [0185]    As illustrated in FIG. 8 g , application of “squeezing” pressure simultaneously on the first and second arms  112  and  114  (illustrated by arrows in FIG. 8 g ) also serves to overcome the bias and move the jaws  40  and  42  from the closed (P 2 ) position to the open (P 1 ) position.  
         [0186]    In P 1 , the jaws  40  and  42  assume an open spaced-apart position corresponding to a first diameter (D 1 ) between the jaws  40  and  42 . This corresponds to an open position, illustrated in FIG. 8 d  and  8   g , in which an external instrument  15  is not able to be held in a fixed position.  
         [0187]    In P 2 , the jaws  40  and  42  assume their normally biased closed adjacently-spaced position corresponding to a second diameter (D 2 ), such that D 2  is less than D 1 . This corresponds to a closed position, best illustrated in FIG. 8 f , in which the jaws  40  and  42  are capable of holding an external instrument  15  in a fixed position.  
         [0188]    The clothespin-clamp  104  may be conventional, formed, e.g., from hard, medical grade plastic by conventional molding techniques.  
         [0189]    In the illustrated embodiment, the clothespin-clamp  104  is carried by an insert  12  for a bite block  10 . Alternately, the clothespin-clamp  104  or any portion of it may be integral with the bite block  10 .  
         [0190]    F. Bite Block Embodiment T 6   
         [0191]    [0191]FIGS. 9 a  and  9   b  detail another embodiment (T 6 ) shown in FIG. 1 b  and its use. This embodiment is similar to embodiment T 5 , except that the jaw assembly  18  is adapted to be eccentrically located within the bite block opening  11  when the insert  12  is positioned within the bite block  10 .  
         [0192]    In the embodiments illustrated in T 1 -T 5 , the jaw assembly  18  is adapted so as to be centrally located within the bite block opening  11  when the insert  12  is positioned within the bite block  10 .  
         [0193]    Alternately, the jaw assembly  18  in any of the embodiments T 1 -T 5  can be positioned so as to be eccentric, as in embodiment T 6 . As previously noted, an eccentric location provides for a larger area in which to insert the external instrument  15  before positioning it within the gripping tool (T).  
         [0194]    G. Bite Block Embodiment T 7   
         [0195]    [0195]FIGS. 10 a - 10   d  detail another embodiment (T 7 ) shown in FIG. 1 c  and its use.  
         [0196]    The embodiment illustrated in FIG. 10 a  provides a C-shaped groove  106  functionally and structurally similar to that contained in embodiment T 6 . However, rather than a generally cylindrical hollow body insert  12 , the C-shaped groove  106  is carried by a clip-on insert  12 ′ as previously described. In this arrangement, the first and second arms  112  and  114  are not provided.  
         [0197]    As best shown in FIGS. 10 b  and  10   d , the first side  94  of the insert  12 ′ includes the C-shaped groove  106 . The groove  106  extends perpendicularly from the third clasp  100 .  
         [0198]    The groove  106  may be coated with an elastomeric material, making the groove  106  more tacky, thereby aiding in grasping an external instrument. This coating can be accomplished by either placing a tube over the groove  106  or placing a low durameter pad over the groove  106 .  
         [0199]    As best seen in FIGS. 10 a  and  10   c , the second side  96  of the insert  12 ′ includes the first and second clasps  98 . In this arrangement, the first and second clasps  98  are positioned exterior to the opening  11  along the bite block  10  wall when the insert  12 ′ is positioned within the bite block  10 . The third clasp  100  and groove  106  are positioned interior to the opening  11  along the bite block  10  wall when the insert  12 ′ is positioned within the bite block  10 .  
         [0200]    In the illustrated embodiment, the groove  106  is adapted to be positioned eccentrically within the opening  11  when the insert  12 ′ is positioned within the bite block  10 . Alternately, the insert  12 ′ can be formed such that the groove  106  is positioned centrally within the opening  11  (not shown).  
         [0201]    In the closed position (see FIG. 8 c ), the groove  106  is capable of holding an external instrument  15  in a fixed position. In the open position (see FIG. 8 e ), the groove  106  is positioned such that the external instrument  15  is not held in a fixed position, allowing it to be inserted or removed.  
         [0202]    The C-shaped groove  106  may be conventional, formed, e.g., from hard, medical grade plastic by conventional molding techniques.  
         [0203]    In the illustrated embodiment, the C-shaped groove  106  is carried by an insert  12 ′ for a bite block  10 . Alternately, the C-shaped groove  106  or any portion of it may be integral with the bite block  10 .  
         [0204]    H. Bite Block Embodiment T 8   
         [0205]    [0205]FIGS. 11 a - 11   d  detail another embodiment (T 8 ) shown in FIG. 1 c  and its use.  
         [0206]    The embodiment illustrated in FIG. 11 a  provides a C-shaped groove  106  mechanism on a clip-on type insert  12 ′ as in embodiment T 7 .  
         [0207]    As best illustrated in FIGS. 11 b  and  11   d , the first side  94  of the insert  12 ′ includes the C-shaped groove  106  as described for embodiment T 7 . However, the groove  106  extends perpendicularly from the first and second clasps  98  rather than from the third clasp  100 .  
         [0208]    As best illustrated in FIGS. 11 a  and  11   c , the second side  96  of the insert  12 ′ includes the third clasp  100 . In this arrangement, the third clasp  100  is positioned exterior to the opening  11  along the bite block  10  wall when the insert  12 ′ is positioned within the bite block  10 . The first and second clasps  98  and groove  106  are positioned interior to the opening  11  along the bite block  10  wall when the insert  12 ′ is positioned within the bite block  10 .  
         [0209]    As in embodiment T 7 , the groove  106  can be coated with an elastomeric material. While the illustrated embodiment shows an eccentric location, the groove  106  can be adapted to be centrally located within the opening  11  when the insert  11  is positioned within the bite block  10 , as previously noted for embodiment T 7 .  
         [0210]    II. Use of the Gripping Tool  
         [0211]    Any one of the gripping tools (T 1 -T 8 ) described can be used with a catheter  58  designed for the treatment of gastroesophageal reflux disease (GERD). One possible embodiment of such a catheter is shown in FIGS. 14 a  and  14   b.    
         [0212]    In the illustrated embodiment, a catheter  58  carries a series of electrodes  60  that, in use, can be coupled to a source of radio frequency energy to ohmically heat tissue and create a lesion in the tissue region, e.g., lower esophageal spinchter  90  (see FIG. 21 b ) or cardia  92  (see FIG. 30) or both. It has been discovered that natural healing of the lesions tightens the targeted and adjoining tissue.  
         [0213]    [0213]FIGS. 14 a  and  14   b  show a representative embodiment for the catheter  58 . Typically, the catheter  58  comprises a catheter tube  19  having a distal region and a proximal region. The proximal region includes a handle  62  incorporating control mechanisms. The distal region carries an expandable structure  64  (e.g., suitable for contacting the lower esophageal sphinchter  90  during performance of procedures for the treatment of GERD, as shown in FIG. 21 b ).  
         [0214]    As also shown in FIGS. 14 a  and  14   b , the expandable structure  64  includes an array of tubular spines  66  that form a basket that is capable of being selectively expanded and contracted. The expandable structure  64  further comprises an expandable body  68  (e.g., balloon) within the basket.  
         [0215]    The purpose of the expandable body  68  is to cause the basket to expand and contract within the esophagus  84 . The expanded structure  64  serves to temporarily dilate the targeted tissue, thus removing some or all the folds normally present in the mucosal surface.  
         [0216]    [0216]FIG. 14 a  shows the expandable structure  64  in the contracted or collapsed position. FIG. 14 b  shows the expandable structure  64  in the expanded position.  
         [0217]    The electrodes  60  are carried within the spines  66  and are similarly capable of extension and retraction. The electrodes  60  are selectively movable between two positions. The first position is a retracted position, illustrated in FIG. 14 a , in which they are withdrawn in a spine  66 . The second position is an extended position, illustrated in FIG. 14 b , in which they extend outward from the spine  66  through a hole in the spine  66 .  
         [0218]    The electrodes  60  can be biased with either an antegrade or retrograde bend. The electrodes  60  can also be arranged in bipolar pairs or in a singular, spaced-apart relation suitable for monopolar operation. In the illustrated embodiment, the electrodes  60  show an antegrade bend and a monopolar arrangement.  
         [0219]    [0219]FIGS. 15 a  and  15   b  illustrate an embodiment in which the expandable structure  64  includes a distal tail  72  adapted to accommodate a guidewire  70 . The purpose of the guidewire  70  is to aid insertion and guidance of the expandable structure  64  and catheter  58  through the oral cavity to a desired position within the esophagus  84  (see FIG. 21 a ). The configuration of the distal tail  72  eliminates the need to thread the guidewire  70  through the expandable structure  64  and the entire body of the catheter  58 .  
         [0220]    In the illustrated embodiment, the distal tail  72  extends approximately 3 inches (range=1 to 5 inches) beyond the distal end of the basket. The distal tail  72  may be conventional, formed, e.g., from semi-rigid, medical grade plastic (e.g., Pebax™, polyurethane, silicone, Santoprene™, or other flexible materials) by conventional molding techniques.  
         [0221]    An interior lumen  74  extends through the distal tail  72 . The interior lumen  74  is a passage that it does not communicate with any other lumen or structure within the body of the catheter  58 . The purpose of the interior lumen  74  is strictly to permit passage of a guidewire  70 . In an alternate embodiment, this lumen  74  could communicate with irrigation or aspiration lumens (not shown).  
         [0222]    This interior lumen  74  terminates at the distal end in an opening  76  in the distal end of the tail  72 . The interior lumen  74  terminates at the proximal end in an orifice  78  that penetrates the wall of the distal tail  72 . In a representative embodiment, the orifice  78  is located approximately midway along the distal tail  72 , or about one and one-half inches from the opening  76 .  
         [0223]    A slot  80  along the axis of the distal tail  72  is provided in the wall of distal tail  72 . In a representative embodiment, the slot  80  extends approximately 1{fraction (1/2 )} inches. The purpose of the slot  80  is to aid in threading a guidewire  70 . The threading of a guidewire  70  through the slot  80  is illustrated in FIGS. 16 a  and  16   b.    
         [0224]    The orifice  78  is located at the distal end of the slot  80 , such that the guidewire  70  is guided by the slot  80  as it is threaded through the orifice  78 . The slot  80  does not penetrate the wall of the distal tail  72 , thus it communicates with the interior lumen  74  in the distal tail  72  only through the orifice  78 . The proximal end of the slot  80  tapers toward the exterior surface of the distal tail  72 , thereby enabling it to guide the guidewire  70  as it is threaded through the distal tail  72 .  
         [0225]    In use, the patient lies awake in a reclined or semi-reclined position. A bite block  10 , desirably carrying a gripping tool (T) as previously described (see, e.g., FIG. 1 a ) is placed in the patient&#39;s mouth and properly positioned, as illustrated in FIG. 17. The gripping elements  17  are placed in the open (P 1 ) position (as shown in FIG. 3 b ).  
         [0226]    The physician passes the small diameter guidewire  70  through the patient&#39;s mouth and pharynx, and into the esophagus  84  to the targeted site, as illustrated in FIG. 18.  
         [0227]    The targeted site for treatment of GERD is typically the lower esophageal sphincter  90  (see FIG. 21 b ) or the cardia  92  of the stomach (see FIG. 30), or both.  
         [0228]    The physician preferably employs an endoscope  86  in conjunction with the guidewire  70  for viewing the targeted site. Use of an endoscope  86  is shown in FIG. 19. The endoscope  86  can be either separately employed in a side-by-side relationship with the guidewire  70 , or the endoscope  86  may be introduced over the guidewire  70  itself. FIG. 19 illustrates employment of an endoscope  86  over a guidewire  70 .  
         [0229]    To aid in determining the position of the endoscope  86 , the tubal body of the endoscope  86  includes measured markings  88  along its length. The markings  88  indicate the distance between a given location along the tubal body and the endoscope  86 .  
         [0230]    Relating the alignment of the markings  88  to the bite block  10 , the physician can gauge, in either relative or absolute terms, the distance between the patient&#39;s mouth and the endoscope  86  in the esophagus  84 . When the physician visualizes the desired treatment site, e.g., lower esophageal sphincter  90  (see FIG. 21 b ) or cardia  92  (see FIG. 30), with the endoscope  86 , the physician records the markings  88  that align with the bite block  10  and removes the endoscope  86 , leaving the guidewire  70  behind.  
         [0231]    In the illustrated embodiment, the catheter tube  19  includes measured markings  88  along its length. The measured markings  88  indicate the distance between a given location along the catheter tube  19  and an operative element (e.g., electrodes  60 ). The markings  88  on the catheter tube  19  correspond in spacing and scale with the measured markings  88  along the tubal body of the endoscope  86 .  
         [0232]    The free proximal end of the guidewire  70  is thread through the opening  76  in the distal tail  72  of the expandable structure  64 , such that the guidewire  70  exits the distal tail  72  through the orifice  78 , as illustrated in FIG. 20.  
         [0233]    The catheter  58  is then advanced along the guidewire  70  through the patient&#39;s mouth and pharynx and to the desired position in the esophagus  84 , e.g., lower esophageal sphincter  90 . The positioning of the catheter  58  in the lower esophageal sphincter  90  is illustrated in FIGS. 21 a  and  21   b.    
         [0234]    An ablation sequence is then performed. The sequence typically comprises the following steps. First, the gripping elements  17  of the gripping tool (T) are moved (represented by arrows in FIG. 22) to the closed (P 2 ) position (shown in FIG. 3 a ), thereby holding the catheter  58  fixed in the desired position, as shown in FIG. 22.  
         [0235]    Second, the expandable body  68  is expanded (e.g., sterile water or air is injected into a balloon through a port in the handle  62  of the catheter  58 , causing it to inflate). The expandable structure  64  is thereby also expanded. FIG. 23 shows the position of the expandable body  68  after expansion.  
         [0236]    Third, the electrodes  60  are extended (e.g., by operation of a push-pull lever on the handle  62  of the catheter  58 ), as illustrated in FIG. 24.  
         [0237]    Fourth, radio frequency energy is applied for a desired period of time (e.g., radio frequency energy in the range of about 400 kHz to about 10 mHz is applied for approximately 90 seconds).  
         [0238]    If desired, cooling liquid can be introduced during the ablation sequence (e.g., each spine  66  can include an interior lumen with a port to convey a cooling liquid like sterile water into contact with the mucosal surface of the targeted tissue site) (not shown).  
         [0239]    Fifth, the electrodes  60  are retracted (e.g., by operation of a push-pull lever on the handle  62  of the catheter  58 ).  
         [0240]    Sixth, the expandable structure  64  is deflated.  
         [0241]    Finally, the elements  17  of the gripping tool (T) are moved to the open (P 1 ) position (shown in FIG. 3 b ), thereby enabling the repositioning or removal of the catheter  58 . The opening of the elements  17  is illustrated by arrows in FIG. 25.  
         [0242]    To create greater lesion density in a given targeted tissue area, it is also desirable to create a pattern of multiple lesions, e.g., in rings along the targeted treatment site.  
         [0243]    For example, multiple lesions may be obtained by performing a series of ablation sequences in both the lower esophageal sphincter  90  (see FIG. 21 b ) and the cardia  92  (see FIG. 30). The physician typically performs a series of ablation sequences in the lower esophageal sphincter  90 , followed by a series of ablation sequences in the cardia  92 , or vice versa.  
         [0244]    For example, a “rotational sequence” is first employed in the lower esophageal sphincter  90  (see FIG. 21 b ). In this sequence, with the elements  17  in the open (P 1 ) position, the catheter  58  is rotated axially a desired number of degrees from the first position, as illustrated by arrows in FIG. 26. The elements  17  of the gripping tool (T) are then moved to the closed (P 2 ) position and a second ablation sequence is performed.  
         [0245]    The pattern of lesions created by such a rotational sequence is shown in FIGS. 27 a - 27   b . FIG. 27 a  corresponds to the pattern resulting from the initial ablation sequence. FIG. 27 b  represents the lesion pattern after one rotation and ablation sequence.  
         [0246]    In the illustrated arrangement, the lesion pattern corresponds to four electrodes  60  spaced at 90 degree angles on the catheter  58  (see FIG. 27 a ). The rotation is of approximately  45  degrees, thereby creating a final lesion pattern comprising a “ring” of eight equidistant lesions (see FIG. 27 b ).  
         [0247]    Of course, a variety of electrode and rotational arrangements may be employed to produce a variety of different lesion patterns.  
         [0248]    In addition to or in place of a rotational sequence, an “axial sequence” may be employed. This process is illustrated in FIGS.  28 - 29 . In this sequence, with the elements  17  in an open position, the catheter  58  is advanced axially within the lower esophageal sphincter  90  from the site of the first ablation sequence, as illustrated by arrow in FIG. 28.  
         [0249]    The elements  17  of the gripping tool (T) are moved to the closed position and a second ablation sequence is then performed. If desired, a rotational sequence is then performed as previously described.  
         [0250]    The catheter  58  is then advanced axially from the site of the second ablation sequence and the process is repeated (not shown).  
         [0251]    The catheter  58  is then advanced axially from the site of the third ablation sequence and the process is repeated (not shown).  
         [0252]    One possible pattern of lesions formed in the lower esophageal sphincter  90  resulting from such a combination of axial and rotational sequences is illustrated in FIG. 29.  
         [0253]    [0253]FIG. 29 corresponds to the lesion pattern resulting from a rotational ablation sequence being performed at each of four different depths within the lower esophageal sphincter  90 . Thus, eight lesions are formed at each of four depths, for a total of thirty-two lesions.  
         [0254]    Of course, a variety of rotational and axial arrangements may be employed to produce a variety of different lesion patterns.  
         [0255]    It is desirable to also form a lesion pattern in the cardia  92  (see FIG. 30) of the stomach in addition to or in place of the lesion pattern formed in the lower esophageal sphincter  90  (see FIG. 21 b ).  
         [0256]    To this end, after completing the desired lesion pattern in the lower esophageal sphincter  90 , the catheter  58  is advanced axially into the cardia  92 . The positioning of the catheter within the cardia  92  is illustrated in FIG. 30.  
         [0257]    A first ablation sequence is then performed. A rotational sequence is then performed if desired. For example, the catheter is rotated a desired number of degrees and a second ablation sequence is performed. The catheter  58  is then rotated the same number of degrees from the site of the first ablation sequence in the opposite direction and a final ablation sequence is performed.  
         [0258]    The pattern of lesions created by such a rotational sequence is shown in FIGS. 31 a - 31   c.    
         [0259]    [0259]FIG. 31 a  corresponds to the pattern resulting from the initial ablation sequence. FIG. 31 b  represents the lesion pattern after the first rotation and ablation sequence. FIG. 31 c  represents the lesion pattern after the second rotation and ablation sequence.  
         [0260]    In the illustrated arrangement, the lesion pattern corresponds to four electrodes  60  spaced at 90 degrees angles on the catheter  58 . The rotation is of approximately 22.5 degrees, thereby creating a final lesion pattern of twelve lesions.  
         [0261]    It is desirable to create a ring of twelve lesions in the cardia  92  rather than a ring of eight lesions as created in the lower esophageal sphincter  90  to cover the larger surface area of the cardia  92 .  
         [0262]    This sequence may be repeated at a second depth in the cardia  92 . FIG. 32 represents the final lesion pattern created after the sequence is repeated at a second depth. The lesion pattern illustrated is that of twelve lesions created at each two depths, for a total of twenty-four lesions created in the cardia  92 .  
         [0263]    Of course, a variety of electrode and rotational arrangements may be employed to produce a variety of different lesion patterns.  
         [0264]    Upon completion of all desired ablation sequences, the physician assures that the electrodes  60  are retracted and the expandable body  68  is contracted (e.g., air or water is withdrawn from the balloon by a syringe through a port on the handle  62  of the catheter  58 ) (not shown).  
         [0265]    The elements  17  of the gripping tool (T) are then verified as being in the open position, the catheter  58  and guidewire  70  are withdrawn, and the bite block  10  is removed from the patient&#39;s mouth (not shown).  
         [0266]    III. Alternative Use of Gripping Tool  
         [0267]    Any one of the gripping tools (T 1 -T 8 ) described can also be used with an alternate embodiment of the previously described catheter  58 . This alternate embodiment enables the threading of a guidewire  70  outside the body of the catheter  58 , through a guidewire lumen  116  within one of the spines  66  of the expandable structure  64 .  
         [0268]    As in the previously described embodiment, and as seen in FIG. 33, the expandable structure  64  includes an array of spines  66  that form a basket that is capable of being selectively expanded and contracted. In a representative embodiment, the expandable structure  64  comprises four spines  66 . Of course, the expandable structure  64  can include a greater or lesser number of spines  66 .  
         [0269]    As will be explained in greater detail later, the guidewire lumen  116  passes through one of the spines  66  outside the catheter  58  and outside expandable body  68 . The guidewire lumen  116  further extends beyond the distal end of the expandable structure  64  through a distal guide assembly  133 .  
         [0270]    As FIG. 31 illustrates, the spines  66  through which the guidewire  70  does not pass, each comprises three lumens, designated L 1 , L 2 , and L 3  in FIG. 33 and subsequent FIGS.  34 - 40 . An arrangement of lumens of this type is detailed in co-pending U.S. patent application Ser. No. 09/955,915, filed Sep. 19, 2001, which is herein incorporated by reference.  
         [0271]    As shown in FIG. 35, the first or center passage L 1  carries a movable, elongated electrode element  118 . The distal end of the electrode element  118  comprises an electrode  60 . The electrode element  118  has a retracted position, in which the distal end of the electrode element  118  is contained within the spine  66 , and an extended position in which the distal end of the electrode element  118  extends out from the spine  66  and is capable of piercing tissue. FIG. 35 shows the distal end of the electrode element  118  in an extended position. When extended, the electrode  60  exits L 1  through an electrode opening  120 .  
         [0272]    As also shown in FIG. 35, a third passage L 3  along side the first passage L 1  is coupled to tubing  123  that carries processing fluid from a fluid delivery device. When desired, e.g., to cool tissue during a procedure, fluid is passed through L 3  and exits L 3  through an irrigation opening  122 . The irrigation opening  122  can be generally aligned with the electrode opening  120  so that ablation and cooling occur in the same general tissue region. Alternatively, the irrigation opening  122  can be proximal or distal to the electrode opening  120 .  
         [0273]    As further shown in FIG. 35, a second passage L 2  along side the first passage L 1  can carry a temperature sensing element  124 , e.g., a thermocouple assembly. In the illustrated embodiment, the thermocouple assembly includes a thermocouple that extends into the L 2  lumen and that carries a temperature sensing element  124 . The temperature sensing element  124  is exposed through a temperature sensor opening  126 . Alternatively, it can extend through the opening  126  and be secured to the spine  66  proximal or distal to the opening  126 .  
         [0274]    The temperature sensor opening  126  can be generally aligned with the electrode opening  120  and irrigation opening  122  so that ablation, temperature sensing, and cooling occur generally in the same localized tissue region. Alternatively, as above discussed, the openings  120 ,  122 , and  126  can be arranged proximal or distal to each other.  
         [0275]    As shown in FIGS. 36 a  and  36   b , the spine  66  that carries the guidewire  70  includes the first and third lumens L 1  and L 3 , which serve to carry, respectively, the electrode  66  and processing fluid tube  123 , as previously described. In this arrangement, the lumen L 2  is desirably adapted to serve as the guidewire lumen  116  for passage of a guidewire  70 , rather than for carrying a temperature sensing element  124 .  
         [0276]    The guidewire lumen  116  is desirably made of a material that is less stiff than the material of the adjacent L 1  and L 3  lumens, e.g., polyurethane, polyethelyne, Pebax™, Peek™, or other suitable material. This assures that, with the guidewire  70  inserted, the stiffness of the guidewire lumen  116  will approximate the stiffness of the adjacent L 1  and L 3  lumens. This assures that the expandable structure  64  is symmetrical upon expansion of the expandable body  68  within the expandable structure  64 .  
         [0277]    [0277]FIG. 36 a  shows an exterior surface (i.e., the surface of the spine facing away from expandable body  68 ) of a section of the spine  66  that carries the guidewire lumen  116 . FIG. 36 b  shows an interior surface (i.e., the surface of the spine facing toward the expandable body  68 ) of the same section of a spine  66 .  
         [0278]    In this arrangement, as best shown in FIG. 36 b , the thermocouple of the temperature sensing element  124  desirably extends along the interior surface of the spine between the L 1  and L 2  lumens. The temperature sensing element  124  is passed through an opening  126  formed between the two lumens L 1  and L 2 , so that it is exposed on the exterior surface of the spine for use. The temperature sensor opening  126  is desirably aligned with the electrode opening  120  and irrigation opening  122  as previously described.  
         [0279]    [0279]FIG. 40 illustrates a guidewire  70  threaded through the guidewire lumen  116  and the guide assembly  133  (see FIG. 33 also). As illustrated in FIG. 37, the guidewire lumen  116  preferably extends both proximally and distally beyond the adjacent L 1  and L 3  lumens. The guidewire lumen  116  has a distal opening  128  located beyond the distal end of the expandable structure  64 . The opening  128  serves as an exit for a guidewire  70  threaded through the guidewire lumen  116  into the guide assembly  113 .  
         [0280]    The guidewire lumen  116  also has a proximal opening  130  that extends proximal of the proximal end of the expandable structure  64 . As also shown in FIG. 37, the proximal opening  130  rests on the exterior of the catheter tube  19 , to provide for an unimpeded passage of the guidewire  70 .  
         [0281]    The guidewire lumen  116  extends entirely outside the body of the catheter tube  19  and entirely outside the expandable body  68 . This path provides stability and support for the expandable structure  64  during passage over the guidewire  70 . The passage of the guidewire  70  through the lumen  116  prevents the guidewire  70  from contacting and/or damaging adjacent functional items carried in the expandable structure  64 . For example, contact between the guidewire  70  and the energy conducting electrode is prevented, to thereby avoiding conduction of ablation energy by or the heating of the guidewire  70 . The passage of the guidewire  70  through the lumen  116  prevents the guidewire  70  from abraiding or rupturing the expandable body  68 .  
         [0282]    As shown in FIG. 37, the distal end of the expandable body  64  includes a guide assembly  133 . In the illustrated embodiment, the guide assembly  133  comprises a two piece construction, having an inner sheath  132  and an outer sheath  134 .  
         [0283]    As shown in FIG. 37, the inner sheath  132  is an elongated member having a proximal region  136  and a distal region  138 . In a representative embodiment, the inner sheath  132  is approximately 1.0 inch to 2.5 inches long (in a most preferred embodiment, it is about 1.75 inches long). A groove  140  (see also FIG. 38) formed in the wall of the inner sheath  132  extends in the proximal and distal regions  136  and  138  and serves to receive the guidewire lumen  116 .  
         [0284]    As FIG. 37 shows, the distal region  138  is generally round with radially extending vanes  142 . In a representative embodiment, the distal region  138  is approximately 1.25 inches long (and the corresponding proximal region  136  being about 0.440 inch long). As illustrated in FIG. 39, the area between the vanes  142  serves to receive the distal end of the spines  66 . In the embodiment illustrated in FIG. 38, there are three vanes  142 . Of course, a greater or lesser number of vanes  142  may be utilized to accommodate a desired number of spines  66 . As shown in FIG. 39, the spines  66  are, e.g., adhesively attached to the inner sheath  132  between the vanes  142 .  
         [0285]    To aid in stability of the overall assembly and support for the expandable structure  64 , the inner sheath  132  is desirably made of a relatively stiff material, having a durometer of, e.g., about  95 A.  
         [0286]    As seen in FIG. 38, an opening  144  in the proximal region  136  is provided. As illustrated in FIG. 39, the opening  144  serves to couple the distal end of the expandable body  68  to the inner sheath  132 .  
         [0287]    The distal region  138  of the inner sheath  132  extends in a taper from the proximal region  136 . In this arrangement, the distal end of the distal region  138  is approximately even with distal end of the guidewire lumen  116 . The guidewire lumen  116 , carried by one of the spines  66 , is located within the groove  140  and is also, e.g., adhesively attached to the inner sheath  132  along the length of the groove  140 .  
         [0288]    As FIG. 37 shows, the outer sheath  134  is a hollow, elongated, tapered member adapted, in the illustrated embodiment, to fit over the inner sheath  132 . When positioned over the inner sheath  132 , the outer sheath  134  extends distally a desired distance beyond the inner sheath  132 . In a representative embodiment, the outer sheath  134  is approximately 1.5 inches to 3.5 inches inches long (in a most preferred embodiment, it is about 2.75 inches long). The distal end of the outer sheath  134  includes an opening  146  accommodating passage of a guidewire  70 .  
         [0289]    The outer sheath  134  is desirably made of a material less stiff than the material selected for the inner sheath  132 , e.g., having a durometer of, e.g., about  60 A. The reduced stiffness provides minimal discomfort to the patient.  
         [0290]    The selection of a relatively stiff material to support the distal end of the expandable structure  64  and of a less stiff material at the distal end of the guide assembly  113  to provide minimal discomfort to the patient, results in a gradient of decreasing stiffness from the proximal end of the guide assembly  113  to the distal end of the guide assembly  113 . This maximizes both stability of the assembly and patient comfort.  
         [0291]    The inner sheath  132  and outer sheath  134  can be formed by conventional molding techniques. Suitable materials for both the inner and outer sheaths  132  and  134  include Kraton™ and Santoprene™.  
         [0292]    Alternately, the inner and outer sheaths  132  and  134  may be molded as a unitary piece utilizing an overmolding process. In this embodiment, the overmolding process permits the manufacture of a single piece having a blended durometer. Thus, a stiffness gradient as previously described can be achieved in a single molded piece.  
         [0293]    In use, the patient lies awake in a reclined or semi-reclined position. A bite block  10 , desirably carrying a gripping tool (T) as previously described is placed in the patient&#39;s mouth and properly positioned (see, e.g., FIG. 17).  
         [0294]    In this embodiment, the gripping tool (T) is an embodiment in which the jaw assembly  18  is eccentrically located within the bite block opening  11  (see embodiments T 6 -T 8 ). The physician passes a small diameter guidewire  70  through the patient&#39;s mouth and pharynx, and into the esophagus  84  to the targeted site, as previously described (see FIG. 18). An endoscope can be deployed as previously described (see FIG. 19).  
         [0295]    Upon removal of the endoscope, the physician threads the guidewire  70  (see FIGS. 33 and 40) by insertion through the distal opening  146  in the guide assembly  133 . The guidewire  70  is advanced into the guidewire lumen  116  of the spine and exits through the proximal opening  130  resting on the exterior surface of the catheter tube  19 .  
         [0296]    As shown in FIG. 12, the catheter  58  is inserted through the opening  11  in the bite block  10  alongside the jaw assembly  18 . The expandable structure  64  is advanced along the guidewire  70  through the patient&#39;s mouth and pharynx and to the desired position in the esophagus  84 , e.g., lower esophageal sphincter  90 . The positioning of the expandable structure  64  in the lower esophageal sphincter  90  is illustrated in FIGS. 21 a  and  21   b.    
         [0297]    As seen in FIG. 13, the catheter tube  19  is then moved laterally to position it within the gripping tool (T 6 , T 7 , or T 8 ) and the catheter tube  19  is positioned within the gripping tool (T 6 , T 7 , or T 8 ), as previously described (see FIGS. 12 and 13).  
         [0298]    An ablation sequence as previously described is then performed (see, e.g, FIGS. 27 a  and  27   b ). Multiple ablation sequences can be performed to create a desired lesion, as previously described (see e.g., FIG. 29). The jaws of the gripping tool are opened each time the catheter tube  19  is repositioned for a new lesion set. Of course, procedures other than ablation may be performed.  
         [0299]    Upon completion of all desired procedures, the physician assures that the electrodes  60  are retracted and the expandable body  68  is contracted (e.g., air or water is withdrawn from the balloon by a syringe through a port on the handle  62  of the catheter  58 ) (not shown).  
         [0300]    The elements  17  of the gripping tool (T) are then verified as being in the open position, the catheter  58  and guidewire  70  are withdrawn, and the bite block  10  is removed from the patient&#39;s mouth.  
         [0301]    While the embodiment just described details the use of the guidewire lumen  116  located within the tubular spines  66  in combination with a gripping tool (T) having an eccentric jaw assembly  18  (see embodiments T 6 -T 8 ), it is to be understood that this embodiment of the guidewire lumen  116  is also adapted for use with a gripping tool (T) having a centrally located jaw assembly  18  (see embodiments T 1 -T 5 ).  
         [0302]    Features and advantages of the invention are set forth in the following claims.