Patent Publication Number: US-2023157749-A1

Title: Ablation device for attachment to an endoscope

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 63/281,951, filed Nov. 22, 2021, pending, the entirety of which is herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure generally relates to ablation devices for attachment to an endoscope, and more particularly, to ablation devices, with suction capabilities, for attachment to an endoscope. 
     BACKGROUND 
     Endoscopic devices and procedures may be used to diagnose, monitor and treat various conditions by close examination of the internal organs. By way of background, a conventional endoscope generally is an instrument having an imaging device for visualizing the interior of an internal region of a body and a lumen for inserting one or more treatment devices therethrough. A wide range of applications have been developed for the general field of endoscopes including by way of non-limiting example the following: arthroscope, angioscope, bronchoscope, choledochoscope, colonoscope, cytoscope, duodenoscope, enteroscope, esophagogastro-duodenoscope (gastroscope), laparoscope, laryngoscope, nasopharyngo-neproscope, sigmoidoscope, thoracoscope, and utererscope (individually and collectively, “endoscope”). 
     By way of non-limiting example, millions of people suffer from progressive gastroesophageal reflux disease (GERD), which is characterized by frequent episodes of heartburn, typically on at least a daily basis. Without adequate treatment, GERD can cause erosion of the esophageal lining as the lower esophageal sphincter (LES), a segment of smooth muscle located at the junction of the stomach and the esophagus, gradually loses its ability to function as the barrier that prevents stomach acid reflux. Chronic GERD can also cause metaplasia to the inner lining of the esophagus where the normal squamous mucosa changes to columnar mucosa, also known as Barrett&#39;s esophagus. Barrett&#39;s esophagus can progress to esophageal cancer if left untreated. 
     Endoscopic treatment of Barrett&#39;s esophagus includes endoscopic mucosal resection (EMR). One method of performing EMR involves ablation of the mucosal surface by heating the surface until the surface layer is no longer viable. The dead tissue is then removed. 
     Treatment devices for performing EMR have been developed using bipolar ablation technology that includes attaching an ablation cap to the distal end of an endoscope, then positioning a probe associated with the cap against the target tissue and delivering energy to the tissue to ablate the tissue in contact with the probe. In some devices, as a safety precaution, if the probe does not make sufficient contact with tissue to be ablated, the probe may not be energized. Thus, to ensure adequate contact between the probe and the target tissue during the procedure, a vacuum associated with the endoscope may supply a suction force within the ablation cap in order to draw the tissue to be ablated into contact with the probe. A consequence of this suction force, however, is that tissue may be drawn into the cap, thereby blocking or obscuring direct endoscopic visualization (e.g., via the imaging device of the endoscope), thereby limiting or preventing accurate positioning of the probe for tissue ablation. 
     In other devices, a preset amount of energy may be delivered to the probe, regardless of the surface area of the probe in contact with tissue, relative to the surface area of the probe not in contact with tissue. In those situations, the amount of energy delivered to the tissue in contact with the probe may exceed a desired level, for example, as compared to the same amount of energy delivered to and distributed among tissue in contact with the entire surface area of the probe. Those situations may present additional safety or other operational concerns. 
     What is needed in the art is an ablation treatment device that is simple to use, that may be coupled to an endoscope, that minimizes the number of steps and time required for a treatment procedure, and that provides treatment under direct endoscopic visualization. 
     SUMMARY 
     The present embodiments provide systems and methods suitable for ablation treatment using an endoscope, while i) maintaining suitable visibility of the target treatment site and surrounding environment, and ii) supplying a vacuum or suction force to draw tissue to be ablated into contact with a probe. 
     In one aspect, an ablation device includes a body having a lumen for receiving a distal end of an endoscope, a cover portion extending from a side of the body, the cover portion defining a recess between the cover portion and the body, and an electrode platform having at least one electrode positioned thereon, the electrode platform movable between a covered position, where the at least one electrode is covered by the cover portion, and an exposed position, where the at least one electrode is at least partially exposed beyond the cover portion. At least one vacuum port is formed in the electrode platform. 
     The at least one vacuum port may include a plurality of vacuum ports arranged about a periphery of the electrode platform. The at least one vacuum port may include a plurality of vacuum ports arranged about a periphery of the at least one electrode. The at least one vacuum port may be surrounded by the at least one electrode. The at least one vacuum port may include a plurality of vacuum ports surrounded by the at least one electrode. 
     A vacuum port of the at least one vacuum port may be circular. A vacuum port of the at least one vacuum port may have a diameter of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be square. A vacuum port of the at least one vacuum port may have a maximum dimension of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be rectangular. A vacuum port of the at least one vacuum port may have a maximum width of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be a longitudinal slot extending along a length of the at least one electrode. A width of the longitudinal slot may be between 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be a transverse slot extending along a width of the at least one electrode. A width of the transverse slot may be between 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may include a longitudinal slot extending along a length of the at least one electrode, and a transverse slot extending along a width of the at least one electrode. A width of the longitudinal slot and the transverse slot may be between 1.0 to 1.5 mm, or less. 
     In some embodiments, a drive catheter extends proximally from the electrode platform. The drive catheter may include at least one lumen. At least one wire may extend from the at least one electrode through a lumen of the at least one lumen. A first lumen of the at least one lumen may be in fluid communication with a first vacuum port of the at least one vacuum port, and a second lumen of the at least one lumen may be in fluid communication with a second vacuum port of the at least one vacuum port. 
     In some embodiments, the electrode platform may include an internal cavity, the at least one vacuum port being in fluid communication with the internal cavity. A drive catheter may extend proximally from the electrode platform, the drive catheter having at least one lumen in fluid communication with the internal cavity. 
     The ablation device may include any one or more of the features above. 
     In another embodiment, an ablation device system includes an endoscope having an imaging device for capturing images at a distal end of the endoscope and one or more fluid lumens extending through at least a portion of the endoscope between a proximal end of the endoscope and the distal end. The system further includes an ablation cap with a body having a lumen for receiving the distal end of the endoscope, and a cover portion extending from a side of the body, the cover portion defining a recess between the cover portion and the body. An electrode platform includes at least one electrode positioned thereon, the electrode platform movable between a covered position, where the at least one electrode is covered by the cover portion, and an exposed position, where the at least one electrode is at least partially exposed beyond the cover portion. At least one vacuum port formed in the electrode platform. 
     The system may include at least one vacuum pump, wherein the at least one vacuum port formed in the electrode platform of the ablation cap and the one or more fluid lumens of the endoscope are in fluid communication with the at least one vacuum pump. The at least one vacuum pump may supply a suction force to the at least one vacuum port formed in the electrode platform of the ablation cap independent of a suction force supplied to the one or more fluid lumens of the endoscope. 
     In some embodiments, the at least one vacuum port may include a plurality of vacuum ports arranged about a periphery of the electrode platform. The at least one vacuum port may include a plurality of vacuum ports arranged about a periphery of the at least one electrode. The at least one vacuum port may be surrounded by the at least one electrode. The at least one vacuum port may include a plurality of vacuum ports surrounded by the at least one electrode. 
     In some embodiments, a vacuum port of the at least one vacuum port may be circular. A vacuum port of the at least one vacuum port may have a diameter of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be square. A vacuum port of the at least one vacuum port may have a maximum dimension of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port is rectangular. A vacuum port of the at least one vacuum port may have a maximum width of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may have a longitudinal slot extending along a length of the at least one electrode. A width of the longitudinal slot may be between 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be a transverse slot extending along a width of the at least one electrode. A width of the transverse slot may be between 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may include a longitudinal slot extending along a length of the at least one electrode, and a transverse slot extending along a width of the at least one electrode. A width of the longitudinal slot and the transverse slot may be between 1.0 to 1.5 mm, or less. 
     In some embodiments, a drive catheter extends proximally from the electrode platform. The drive catheter may include at least one lumen. At least one wire may extend from the at least one electrode through a lumen of the at least one lumen. A first lumen of the at least one lumen may be in fluid communication with a first vacuum port of the at least one vacuum port, and a second lumen of the at least one lumen may be in fluid communication with a second vacuum port of the at least one vacuum port. 
     In some embodiments, the electrode platform may include an internal cavity, the at least one vacuum port being in fluid communication with the internal cavity. A drive catheter may extend proximally from the electrode platform, the drive catheter having at least one lumen in fluid communication with the internal cavity. 
     The ablation device system may include any one or more of the features above. 
     In yet another embodiment, an ablation device includes an electrode platform having at least one electrode positioned thereon, a drive catheter extending from the electrode platform, the drive catheter having at least one lumen, and, at least one vacuum port formed in the electrode platform, the at least one vacuum port in fluid communication with the at least one lumen. The at least one vacuum port and the electrode platform are movable in unison via movement of the drive catheter. 
     In some embodiments, the at least one vacuum port may include a plurality of vacuum ports arranged about a periphery of the electrode platform. The at least one vacuum port may include a plurality of vacuum ports arranged about a periphery of the at least one electrode. The at least one vacuum port may be surrounded by the at least one electrode. The at least one vacuum port may include a plurality of vacuum ports surrounded by the at least one electrode. 
     In some embodiments, a vacuum port of the at least one vacuum port may be circular. A vacuum port of the at least one vacuum port may have a diameter of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be square. A vacuum port of the at least one vacuum port may have a maximum dimension of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be rectangular. A vacuum port of the at least one vacuum port may have a maximum width of 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be a longitudinal slot extending along a length of the at least one electrode. A width of the longitudinal slot may be between 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may be a transverse slot extending along a width of the at least one electrode. A width of the transverse slot may be between 1.0 to 1.5 mm, or less. A vacuum port of the at least one vacuum port may include a longitudinal slot extending along a length of the at least one electrode, and a transverse slot extending along a width of the at least one electrode. A width of the longitudinal slot and the transverse slot may be between 1.0 to 1.5 mm, or less. 
     In some embodiments, at least one wire extends from the at least one electrode through a lumen of the at least one lumen. A first lumen of the at least one lumen may be in fluid communication with a first vacuum port of the at least one vacuum port, and a second lumen of the at least one lumen may be in fluid communication with a second vacuum port of the at least one vacuum port. The electrode platform may include an internal cavity, the at least one vacuum port being in fluid communication with the at least one lumen through the internal cavity. 
     In some embodiments, the ablation device further includes a body having a lumen for receiving a distal end of an endoscope, wherein the at least one vacuum port and the electrode platform are movable relative to the body in unison via movement of the drive catheter. 
     In some embodiments, the ablation device further includes a cover portion extending from a side of the body, the cover portion defining a recess between the cover portion and the body, wherein the electrode platform is movable between a covered position, where the at least one electrode is covered by the cover portion, and an exposed position, where the at least one electrode is at least partially exposed beyond the cover portion. 
     The ablation device may include any one or more of the features above. 
     Other systems, methods, features and advantages of the described embodiments will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be within the scope of the disclosure, and be encompassed by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views. 
         FIG.  1    is a perspective view of an ablation cap with an electrode platform in a covered position, in accordance with an embodiment of the present disclosure; 
         FIG.  2    is a perspective view of the ablation cap shown in  FIG.  1   , with the electrode platform in an extended position; 
         FIG.  3    is a side view of the ablation cap shown in  FIG.  1   ; 
         FIG.  4    is an front view the ablation cap shown in  FIG.  1   ; 
         FIG.  5    is a rear view of the ablation cap shown in  FIG.  1   ; 
         FIG.  6    is a cross-sectional side view of the ablation cap shown in  FIG.  1   , with the electrode platform in a covered position, taken along line  6 - 6  in  FIG.  4   . 
         FIG.  7    is a partial view of an embodiment of a support member of the ablation cap; 
         FIG.  8    is a partial view of an embodiment of a support member of the ablation cap 
         FIG.  9    illustrates an embodiment of an electrode of the ablation cap; 
         FIG.  10    illustrates an embodiment of an electrode of the ablation cap; 
         FIG.  11    illustrates the distal end of an exemplary endoscope for use with the ablation caps of the present disclosure; 
         FIG.  12    is a perspective view of an electrode platform and drive catheter, in accordance with an embodiment of the present disclosure; 
         FIG.  13    is a top view of the electrode platform and drive catheter shown in  FIG.  12   ; 
         FIG.  14    is a bottom view of the electrode platform and drive catheter shown in  FIG.  12   ; 
         FIG.  15    is a cross-sectional side view of the electrode platform and drive catheter shown in  FIG.  12   , taken along line  15 - 15  in  FIG.  13   ; 
         FIG.  16    is a perspective view of another electrode platform, in accordance with an embodiment of the present disclosure; 
         FIG.  17    is a top view of the electrode platform shown in  FIG.  16   ; 
         FIG.  18    is a perspective view of another electrode platform, in accordance with an embodiment of the present disclosure; 
         FIG.  19    is a top view of the electrode platform shown in  FIG.  18   ; 
         FIG.  20    is a perspective view of another electrode platform, in accordance with an embodiment of the present disclosure; 
         FIG.  21    is a top view of the electrode platform shown in  FIG.  20   ; 
         FIG.  22    is a perspective view of another electrode platform, in accordance with an embodiment of the present disclosure; 
         FIGS.  23 A- 23 C  illustrate operation of the ablation cap. 
     
    
    
     DETAILED DESCRIPTION 
     In the present application, the term “proximal” refers to a direction that is generally towards a physician during a medical procedure, while the term “distal” refers to a direction that is generally towards a target site within a patient&#39;s anatomy during a medical procedure. As used herein to describe example embodiments, the term “fluid” may refer to a gas or a liquid. 
       FIGS.  1 - 6    illustrate an embodiment of an ablation cap  10  in accordance with the present disclosure. As shown, the ablation cap  10  includes a tubular body  12  having a lumen  14  formed therein. The ablation cap  10  includes a proximal portion  16  and a distal portion  18 . As shown in, the proximal portion  16  of the cap  10  is sized to fit on a distal end  20  of an endoscope  22  (shown in  FIG.  11   ). In some embodiments, the proximal portion  16  of the ablation cap  10  may include a flexible portion  26  that is connected to the tubular body  12  and that fits over the distal end  20  of the endoscope  22  to secure the cap  10  to the endoscope  22 , for example, by friction fit. In some embodiments, the proximal portion  16  may be made of a hard material that is sized and shaped to fit over the distal end  20  of the endoscope  22  by friction fit. 
     The distal portion  18  of the ablation cap  10  may extend beyond the distal end  20  of the endoscope  22 . The distal portion  18  may be cylindrical. In some embodiments, the distal portion  18  may be formed from a material having sufficient transparency so that the operator using an imaging device  100  of the endoscope  22  may observe a portion of the tissue to be treated by viewing the tissue through a wall  24  of the distal portion  18  of the ablation cap  10 . The distal portion  18  may also include a portion that is formed from a material for magnifying the tissue under observation. The cap  10  may further include a hood or a cover portion  29  that includes a recess  30  formed as part of the ablation cap  10 . The cover portion  29  may be integrally formed with the cap  10  or provided as a separate portion and connected to the cap  10 . The cover portion  29  is at least partially spaced apart from the tubular body to form the recess  30 . The recess  30  may be sized and shaped to hold an extendable electrode platform  34  within the recess  30  in a covered position, as shown in  FIGS.  1  and  6   . The electrode platform  34  is slidably positionable within the recess  30  of the cover portion  29 . In some embodiments, the electrode platform  34  may be positioned entirely within the recess  30  of the cover portion  29  in the covered position so that electrodes positioned on the electrode platform  34  are completely covered. As shown in  FIG.  2   , the electrode platform  34  may be extended distally from the recess  30  so that at least a portion of a surface  35  of the electrode platform is exposed and can contact the tissue to be treated. A portion of the wall  24  is positioned behind the electrode platform  34  when the electrode platform  34  is an exposed position and may be used to support the electrode platform  34  when the electrode platform  34  is pressed against the tissue to be treated. In some embodiments, a distal end  36  of the electrode platform  34  does not extend beyond a distal end of the distal portion  18  of the cap  10 . 
     In some embodiments, a distal end  36  of the electrode platform  34  is extended less than the extension as shown in  FIG.  2   . By way of non-limiting example, the distal end  36  may be extended less than 100% or about 20%, 40%, 60% and 80% of the extension shown in  FIG.  2   . Other extension distances are also possible. In some embodiments, the electrode platform  34  may be colored to facilitate viewing the electrode platform  34  as it is advanced distally and to determine the amount that the electrode platform  34  has been extended. For example, the electrode platform  34  may be black or blue or any color that may be seen through an endoscope to help viewing the position of the electrode platform  34 . In some embodiments, the cap  10  may include a stop to stop the electrode platform  34  at a maximum extension and to prevent the electrode platform from extending too far out of the cap  10 . 
     In some embodiments, at least a portion of the electrode platform  34  may be viewable through the endoscope. The electrode platform  34  may move into and out of the view of the endoscope, for example, when the electrode platform  34  has been extended a certain percent relative to the cap  10 , the electrode platform  34  may be viewed through the endoscope. By way of non-limiting example, the electrode platform  34  may be viewed when 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% or other amount has been extended distally from the retracted position of  FIG.  1   . Electrodes positioned on the electrode platform  34  may also be energized when the electrode platform  34  is extended distally less than 100%. 
     A cross-sectional side view of the ablation cap  10  is shown in  FIG.  6   . The lumen  14  extends through the ablation cap  10  between the proximal portion  16  and the distal portion  18 . The electrode platform  34  is shown within the recess  30  of the cover portion  29 . In the embodiment shown, a beveled portion  48  is positioned on a distal edge of the recess  30 . The beveled portion  48  may be used to help prevent tissue entrapment within the recess  30 , for example, by scraping ablated tissue off the electrode platform  34 , when the electrode platform  34  is retracted in a proximal direction, to a position within the cover portion  29 . 
     As shown in  FIGS.  7  and  8   , the electrode platform  34  may be connected to a drive catheter  42  that extends proximally from the electrode platform  34 , through an opening  43  (see  FIG.  5   ) in the rear of the cover portion  39 , to a proximal control handle (not shown). The drive catheter  42  is distally movable to extend the electrode platform  34  from the recess  30  of the cover portion  29  and proximally movable to re-position the electrode platform  34  within the recess  30 . Typically, the electrode platform  34  is positioned within the recess  30  of the cover portion  29  when the ablation cap  10  is being delivered to a treatment site or being repositioned within a patient&#39;s lumen for additional treatment at one or more additional sites. Positioning of the electrode platform  34  within the recess  30  also helps to prevent accidental energy delivery, for example to healthy tissue. The electrode platform  34  is at least partially distally extended from the recess  30  of the cover portion  29  for treatment at a site and energy is delivered to the tissue to ablate the diseased tissue as described in more detail below. 
     In some embodiments, the electrode platform  34  may include a support member  62  upon which one or more electrodes  64  are positioned.  FIGS.  7  and  8    illustrate exemplary support members  62 . As shown in  FIG.  7   , the support member  62  may be a solid material, such as a plastic material. As shown in  FIG.  8   , the support member  62 , may be a mesh. When the solid material or the mesh is formed of a metallic material, a layer of insulation may be provided between the support member  62  and the electrodes  64 . The support member  62  may be moved proximally and distally with the drive catheter  42 . The electrodes  64  may be secured to the support member  62  by any method known to one skilled in the art. By way of non-limiting example, the electrodes may be secured by gluing, bonding, taping, an adhesive backing on the electrodes, crimping, manufacturing the electrodes directly on to the body and the like. 
     Electrical wires  72  may extend through a lumen  74  of the drive catheter  42  as shown in  FIGS.  7  and  8    and connect to the electrodes  64  to supply the energy for ablation. Alternatively, the electrical wires  72  may extend through a lumen of the endoscope  22 . Exemplary electrodes  64  may be seen in  FIGS.  8  and  9   . The electrodes  64  may be provided separately from the support member  62  and in some embodiments may also form the support member  62  without providing a separate support member. 
     As shown In  FIGS.  8  and  9   , the electrodes  64  may include positive electrodes  64  and negative electrodes  64  in a bipolar device. When provided as a bipolar device, the electrodes  64  are provided in pairs, one positive and one negative electrode per pair. The electrodes  64  may also be provided as a monopolar device having a single electrode  64  or a plurality of electrodes  64  with a grounding pad or an impedance circuit additionally provided (not shown). The electrodes  64  may be provided in any pattern on the support member  62 . The electrodes  64  may cover the entire support member  64  or a portion thereof. By way of non-limiting example, a space  62  between the positive electrode  64  and the negative electrode  64  may between about 0.1 mm to about 5 mm. In some embodiments, the energy may be delivered to the tissue for a period of time from about 0.1 second to about 10 seconds. In some embodiments, the amount of energy delivered to the tissue may be from about 10 watts to about 60 watts. Other spacing distances between electrodes, length of time, and energy delivery are also possible and depend on the target tissue, the depth of the lesion, the type of energy, the length of application of the energy to the tissue and the spacing of the electrodes. 
     The electrodes  64  are operably connected to an energy source (not shown). In some embodiments, the energy source may be a radio frequency source. However, other types of energy sources may also be used to provide energy to the electrodes. By way of non-limiting example, additional possible energy sources may include microwave, ultraviolet, cryogenic and laser energies. 
     In some embodiments, the ablation cap may be made primarily of a substantially transparent or translucent polymer such as polytetrafluorothylene (PTFE). Additional possible materials include, but are not limited to the following, polyethylene ether ketone (PEEK), fluorinated ethylene propylene (FEP), perfluoroalkoxy polymer resin (PFA), polyamide, polyurethane, high density or low density polyethylene, and nylon. In some embodiments, the ablation cap may be formed from a lubricious material such as PTFE and the like for easy slidability within the patient&#39;s lumen for delivery to the treatment site. In some embodiments, the ablation cap or a portion thereof may be formed from magnifying or other image enhancing materials. The ablation cap or a portion thereof may also be coated or impregnated with other compounds and materials to achieve the desired properties. Exemplary coatings or additives include, but are not limited to, parylene, glass fillers, silicone hydrogel polymers and hydrophilic coatings. 
       FIG.  11    illustrates the distal end  20  of an exemplary endoscope  22  for use with the ablation caps of the present disclosure. In some embodiments, the endoscope  22  may include an imaging device  100  extending through at least a portion of endoscope  22  between a proximal end of the endoscope  22  and the distal end  20 . The imaging device  100  may include a lens operatively coupled to, e.g., in signal communication with, an external imaging system and is configured to capture images of the target site and transmit signals indicative of the captured images to the imaging system. The endoscope  22  may also include an accessory channel  102  extending through at least a portion of the endoscope  20  between a proximal end of the endoscope  22  and the distal end  20 . The accessory channel  102  may be used to delivery any number of accessories or devices, such as a catheter (not shown), to the distal end  22  of the endoscope  20 . Endoscope  22  may further include one or more light sources  104 , such as light-emitting diodes (LEDs), and a water source  106  configured to inject water into the target site. Finally, the endoscope  22  may include one or more fluid lumens  108  extending through at least a portion of the endoscope  20  between a proximal end of the endoscope  22  and the distal end  20 . The one or more fluid lumens  108  may be in fluid communication with an external source of a pressurized fluid (e.g., gas such as carbon dioxide or a liquid) to aerate the target site. Alternatively, or additionally, the one or more fluid lumens  108  may be in fluid communication with a vacuum pump to withdraw fluid from the target site and/or to supply a suction force within the cap  10  in order to draw the tissue to be ablated into contact with the electrodes  64 . 
       FIGS.  12 - 22    illustrate additional electrode platforms and drive catheters in accordance with additional embodiments of the present disclosure. The electrode platforms and drive catheters of  FIGS.  12 - 22    may be used in conjunction with the ablation cap  10  of  FIGS.  1 - 6   , or other ablation caps, and/or in conjunction with the endoscope  22  of  FIG.  11   , or other endoscopes. The structure of the electrode platform  134  and drive catheter  142  of  FIGS.  12 - 15    is exemplary of the structures of the electrode platforms  234 ,  334 ,  434 , and  534  illustrated in  FIGS.  16 - 22   , except as described below. 
     Similar to prior embodiments,  FIGS.  12 - 15    illustrate an electrode platform  134  having one or more electrodes  164  arranged in a central portion of the electrode platform  134 . A drive catheter  142  defining a central lumen  174  extends proximally from the electrode platform  134 . The drive catheter  142  may be movable distally to extend the electrode platform  134  from the recess  30  of the cover portion  29  and movable proximally to re-position the electrode platform  134  within the recess  30 . Electrical wires  172  may extend through the lumen  174  of the drive catheter  142  and connect to the electrodes  164  to supply the energy for ablation. 
     Unlike prior embodiments, the electrode platform  134  comprises one or more vacuum ports  176  formed on the surface  135  of the electrode platform  134 . The vacuum ports  176  extend through the surface  135  and are in fluid communication with a central cavity  178  of the electrode platform  134 , as illustrated in the cross-sectional view of  FIG.  15   . In turn, the central cavity  178  is in fluid communication with the central lumen  174  of the drive catheter  142 . The central lumen  174  may be in fluid communication with a vacuum pump (not shown) positioned at a proximal end of the drive catheter  174 . In this way, the one or more vacuum ports  176  may be used to selectively supply a suction force to draw tissue in the vicinity of the of the electrode platform  134  toward the one or more electrodes  164 , without relying on the fluid port  108  of the endoscope  22 . 
     In the embodiment of  FIGS.  12 - 15   , four vacuum ports  176  are arranged about the periphery of the electrode platform  134 , and about the periphery of the one or more electrodes  164 , in a generally rectangular orientation. In some embodiments, the electrode platform may have fewer than four vacuum ports  176 , or more than four vacuum ports  176 . In some embodiments, the vacuum ports  176  may be circular, and have a diameter of 1.0 to 1.5 mm, or less. In other embodiments, the vacuum ports  176  may have other shapes, such as a square, a rectangle, or other elongated shape. In general, however, the vacuum ports  176  will be sized so that no significant amount of ablated and/or loose tissue will be drawn into the vacuum ports  176 , where such tissue may build-up and/or clog the cavity  178  or lumen  174 . In general, such openings will have a dimension (e.g., diameter, width, etc.) in the range of 1.0 to 1.5 mm, or less. 
     In the embodiment of  FIGS.  12 - 15   , the vacuum ports  176  are arranged about the periphery of the one or more electrodes  164 . Advantageously, this orientation does not disrupt the surface of the one or more electrodes  164 , thereby maintaining the surface area thereof for ablation of tissue, while still providing a distributed suction force around the periphery of the electrodes  164 . Likewise, vacuum ports  176  in the form of multiple small holes or openings distributed about the surface  135  of the electrode platform  134 , rather than one or more larger openings, helps maintains the rigidity of the electrode platform  134 , thereby facilitating the ability to position the electrode platform  134 . In this embodiment, the distributed suction force supplied by the vacuum ports  176 , about the periphery of the electrodes  164 , effectively draws adjacent tissue uniformly into contact across the entire surface area of the electrodes  164 . 
     While the drive catheter  142  and electrode platform  134  of  FIG.  15    illustrates a single lumen  174 , and a single cavity  178 , for communication with a vacuum pump (not shown), and/or an energy source (not shown) via wires  177 , in other embodiments, the drive catheter  142  may have multiple separate lumens, in communication with multiple separate cavities and/or vacuum ports  176 . For example, the drive catheter  142  may have one lumen for housing the wires  177 , a second lumen in communication with a cavity and one or more select vacuum ports  176 , and a third lumen in communication with another cavity and one or more other vacuum ports  176 , where the second and third lumens are also selectively in communication with one or more vacuum pumps. In this way, a suction force may be selectively delivered to one or more of the vacuum ports  176 , as desired, or all of the vacuum ports  176 . In some embodiments, the one or more vacuum ports  176  may be monitored, individually or collectively, to determine if adequate contact is achieved between the electrode platform  134  (and one or more electrodes  164  mounted thereon) and target tissue site. For example, the one or more vacuum ports  176  may be individually or collectively monitored to determine if a negative pressure is created and maintained within the one or more lumens  174  and/or cavities  178 , thereby indicating contact between the target tissue and the electrode platform  134 , at least in the region of the individual vacuum ports  176 . 
     Additionally, or alternatively, in some embodiments, the one or more vacuum ports  176  (and related cavities and lumens) may be in communication with a source of pressurized fluid (e.g., carbon dioxide, or saline solution), for purposes of flushing the lumen  174 , cavity  178 , and/or vacuum ports  176 , for example, to expel ablated tissue. The pressurized fluid may also serve to “rinse” the surface  135  of the electrode platform  134 , for example, to assist the release of ablated tissue from the surface  135 . 
       FIGS.  16 - 17    illustrate an electrode platform  234  according to another embodiment of the present disclosure. In the embodiment of  FIGS.  16 - 17   , one or more vacuum ports  276  are arranged along the lateral edges of one or more electrodes  264 . In some embodiments, the vacuum ports  276  may be formed as longitudinal slots, having a length corresponding to a length of the electrodes  234 , and a width of 1.0 to 1.5 mm, or less. In other embodiments, the length of the longitudinal slots may be greater than or less than the length of the electrodes  234 . Advantageously, this orientation does not disrupt the surface of the one or more electrodes  264 , thereby maintaining the surface area thereof for ablation of tissue, while still providing a distributed suction force along the entire length and lateral edges of the one or more electrodes  264 . In this embodiment, the distributed suction force supplied by the vacuum ports  276 , along the lateral edges of the electrodes  264 , effectively draws adjacent tissue uniformly into contact across the entire surface area of the electrodes  264 . 
       FIGS.  18 - 19    illustrate an electrode platform  334  according to another embodiment of the present disclosure. In the embodiment of  FIGS.  18 - 19   , one or more vacuum ports  376  are arranged along the proximal and distal edges of one or more electrodes  364 . In some embodiments, the vacuum ports  376  may be formed as transverse slots, having a length corresponding to a width of the electrodes  334 , and a width of 1.0 to 1.5 mm, or less. In other embodiments, the length of the transverse slots may be greater than or less than the width of the electrodes  334 . Advantageously, this orientation does not disrupt the surface of the one or more electrodes  364 , thereby maintaining the surface area thereof for ablation of tissue, while still providing a distributed suction force along the entire width and proximal and distal edges of the one or more electrodes  364 . In this embodiment, the distributed suction force supplied by the vacuum ports  376 , along the entire width and proximal and distal edges of the one or more electrodes  364 , effectively draws adjacent tissue uniformly into contact across the entire surface area of the electrodes  364 . 
       FIGS.  20 - 21    illustrate an electrode platform  434  according to another embodiment of the present disclosure. In the embodiment of  FIGS.  20 - 21   , one or more vacuum ports  476  are arranged along the lateral edges, and the proximal and distal edges, of one or more electrodes  464 . In some embodiments, the vacuum ports  476  may be formed as slots, having both a longitudinal portion, extending along a portion of the length of the electrodes  464 , and a transverse portion, extending along a the width of the electrodes. Again, the slots may have a width of 1.0 to 1.5 mm, or less. In some embodiments, the longitudinal portions of the vacuum ports  476  may extend substantially the length of the electrodes  464 . However, it should be appreciated that the entire periphery of the electrodes are not surrounded by the vacuum ports  476 , as at least a portion of the surface of the electrode platform  434  must remain to support the electrodes  464 . Advantageously, this orientation does not disrupt the surface of the one or more electrodes  464 , thereby maintaining the surface area thereof for ablation of tissue, while still providing a distributed suction force along both the length and width, and on all sides of the or more electrodes  464 . In this embodiment, the distributed suction force supplied by the vacuum ports  476 , along both the length and width of the one or more electrodes  464 , effectively draws adjacent tissue uniformly into contact across the entire surface area of the electrodes  464 . 
       FIG.  22    illustrates an electrode platform  534  according to another embodiment of the present disclosure. In the embodiment of  FIG.  22   , one or more vacuum ports  576  are arranged within, or are surrounded by, one or more electrodes  564 . In some embodiments, the vacuum ports  576  may be circular, and have a diameter of 1.0 to 1.5 mm, or less. In other embodiments, the vacuum ports  576  may have other shapes, such as a square, a rectangle, or other elongated shape. Advantageously, this orientation provides a distributed suction force originating in multiple locations within, or surrounded by the one or more electrodes  564 , thereby drawing tissue to be ablated to a specific locations within the electrodes  564 . In this embodiment, a distributed suction force may be supplied by the vacuum ports  576 , depending on the location, number, and shape of the vacuum ports  576 , to effectively draw adjacent tissue uniformly into contact across the entire surface area of the electrodes  564 . 
     In other embodiments, an electrode platform may have one or more combinations of the orientations of the vacuum ports  176 ,  276 ,  376 ,  476 ,  576 . For example, an electrode platform may have vacuum ports  176  and  576 , in the form of circular holes, formed about the periphery of one or more electrodes, and within, or surrounded by, the one or more electrodes. It should be appreciated that the any number of combinations and orientations of vacuum ports may be positioned on an electrode platform without departing from the scope of the present disclosure. The embodiments described and illustrated herein are only exemplary. 
     Operation of an ablation device using the endoscope  22 , the ablation cap  10 , and an electrode platform (e.g.,  134 ,  234 ,  334 ,  434 , and/or  534 ) of the present disclosure as a non-limiting example will be explained with reference to  FIGS.  23 A-C .  FIG.  23 A  illustrates a patient&#39;s esophagus  80 , lower esophageal sphincter (LES)  81  and stomach  82 . Areas of diseased tissue  84  within the esophagus  80  are also shown. The diseased tissue  84  may be columnar mucosa (Barrett&#39;s esophagus) that is to be ablated using the ablation cap  10 .  FIG.  23 B  illustrates the ablation cap  10  positioned on the distal end  20  of the endoscope  22  and the cap  10  and the endoscope  22  being inserted into the patient&#39;s esophagus  80 . The ablation cap  10  is positioned in the esophagus  80  near the portion of the diseased tissue  84  to be treated. The insertion of the ablation cap  10  may be monitored using the imaging device  100  of the endoscope  22  to help position the cap  10  at the diseased tissue. As shown in  FIG.  23 B , the ablation cap  10  is positioned near the diseased tissue  84 . While the ablation cap  10  is being positioned, the electrode platform (e.g.,  134 ,  234 ,  334 ,  434 , and/or  534 ) is in a covered position  44  within the ablation cap  10 . Then, when the ablation cap  10  is in the desired position, the electrode platform may be advanced distally from the cap  10  to an exposed position  46 . Once in an exposed position  46 , a suction force may be selectively delivered from a vacuum source to one or more vacuum ports (e.g.,  176 ,  276 ,  376 ,  476 , and/or  576 ) on the electrode platform to draw nearby tissue in to contact with the electrodes on the electrode platform, as shown in  FIG.  23 C . Advantageously, this step may also be may be monitored using the imaging device  100  of the endoscope  22  to help ensure that the target tissue (and not healthy tissue) is in the desired contact with the electrode platform. When the diseased tissue  84  is in sufficient contact with the electrode platform  34 , the electrodes  64  are in contact with the diseased tissue  84  and can deliver energy to the diseased tissue  84  to ablate the diseased tissue  84 . A power source (not shown) is activated for a sufficient time to ablate the diseased tissue  84 . The ablation cap  10  may then be repositioned near another portion of diseased tissue  84  for treatment and the steps repeated as many times as needed. The electrode platform  34  may be extended and viewed through the imaging device  100  as the electrode platform  34  extends distally. When necessary, a fluid from a fluid source may be delivered to the one or more vacuum ports to flush the vacuum ports and/or “rinse” the surface of the electrode platform. While the procedure has been described with reference to the ablation of diseased tissue in the esophagus using the ablation cap  10 , the location of the treatment is not limited to the esophagus. By way of non-limiting example, portions of the stomach, or the gastrointestinal tract may also be treated using the ablation cap  10 . 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the claims. 
     One skilled in the art will realize that a virtually unlimited number of variations to the above descriptions are possible, and that the examples and the accompanying figures are merely to illustrate one or more examples of implementations. 
     It will be understood by those skilled in the art that various other modifications can be made, and equivalents can be substituted, without departing from claimed subject matter. Additionally, many modifications can be made to adapt a particular situation to the teachings of claimed subject matter without departing from the central concept described herein. Therefore, it is intended that claimed subject matter not be limited to the particular embodiments disclosed, but that such claimed subject matter can also include all embodiments falling within the scope of the appended claims, and equivalents thereof. 
     In the detailed description above, numerous specific details are set forth to provide a thorough understanding of claimed subject matter. However, it will be understood by those skilled in the art that claimed subject matter can be practiced without these specific details. In other instances, methods, devices, or systems that would be known by one of ordinary skill have not been described in detail so as not to obscure claimed subject matter. 
     Reference throughout this specification to “one embodiment” or “an embodiment” can mean that a particular feature, structure, or characteristic described in connection with a particular embodiment can be included in at least one embodiment of claimed subject matter. Thus, appearances of the phrase “in one embodiment” or “an embodiment” in various places throughout this specification are not necessarily intended to refer to the same embodiment or to any one particular embodiment described. Furthermore, it is to be understood that particular features, structures, or characteristics described can be combined in various ways in one or more embodiments. In general, of course, these and other issues can vary with the particular context of usage. Therefore, the particular context of the description or the usage of these terms can provide helpful guidance regarding inferences to be drawn for that context.