Patent Publication Number: US-2023157750-A1

Title: Ablation device for attachment to an endoscope

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 63/281,965, filed on 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 a pivoting electrode, 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’s esophagus. Barrett’s esophagus can progress to esophageal cancer if left untreated. 
     Endoscopic treatment of Barrett’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. 
     Treatment with such devices is not limited to the esophagus. Rather, target sites for ablation may include tissue within the stomach, lower colon, small intestine, and rectum, among other locations. Such tissues may not be substantially flat, and may be formed just inside the entry to an organ. Due to anatomical geometry at such locations, and/or the tortous path leading to target sites in such locations, rigid electrode platforms and drive catheters may prevent a probe from making the desired contact with the tissue to be ablated, thereby preventing optimal treatment. Moreover, if adequate contact with tissue is not obtainable, such probe may not be energized. 
     By way of example, a target tissue site formed in the wall of the stomach may be curved, whether concave or convex, and may be located just beyond the cardia, for example, in a region of the fundus. A rigid electrode platform and drive catheter entering the stomach through the esophagus may not be positionable to reach the target tissue and/or make the desired contact for purposes of ablation. By way of further example, a target tissue site formed in the colon or small intestine may be formed on or just beyond a sharp bend in those organs, making delivery and sufficient contact of a probe with a rigid electrode platform and drive catheter particularly challenging, if not impossible. 
     What is needed in the art is an ablation treatment device that is simple to use, that is coupled to the endoscope, that minimizes the number of steps and time required for a treatment procedure, and that provides improved treatment of target tissue sites formed in challenging locations. 
     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) providing increased flexibility and maneuverability of an ablation device. 
     In one aspect, an ablation cap includes a body having a lumen for receiving a distal end of an endoscope, the body having a central axis extending therethrough, and, at least one guide for receiving at least one lateral extension of an electrode platform, wherein at least a portion of the at least one guide extends at an angle relative to the central axis of the body. 
     In some embodiments, the angle relative to the central axis of the body may be between 30 degrees and 60 degrees. Alternatively, the angle relative to the central axis of the body may be less than 30 degrees. 
     In some embodiments, the at least one guide may include a proximal portion parallel to the central axis of the body. In some embodiments, the at least one guide may include a distal portion angled relative to the central axis of the body. 
     In some embodiments, the ablation cap may further include a cover portion extending from a side of the body, the cover portion defining a recess between the cover portion and the body. The at least one guide may extend along at least a portion of the cover portion within the recess. 
     In some embodiments, the body may include an angled portion formed at an angle relative to the central axis of the body. The at least one guide may extend along the angled portion. 
     In some embodiments, the at least one guide includes a first portion extending at a first angle relative to the central axis of the body and a second portion extending at a second angle relative to the central axis of the body, the second angle being different than the first angle. 
     In some embodiments, the at least one guide is a channel. Alternatively, the at least one guide may be a rail. 
     In some embodiments, the at least one guide may include a first guide and a second guide, the first guide and the second guide being parallel. 
     In some embodiments, the body may be tubular. 
     The ablation device may include any one or more of the features above. 
     In another embodiment, an ablation device includes a body having a lumen for receiving a distal end of an endoscope, the body having a central axis extending therethrough, 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 lateral extension, the electrode platform movable between a covered position, where the electrode platform is covered by the cover portion, and an exposed position, where the electrode platform is not covered by the cover portion. At least one guide receives the at least one lateral extension of the electrode platform, wherein a portion of the at least one guide extends at an angle relative to the central axis of the tubular body. 
     In some embodiments, the at least one extension of the electrode platform is slidable within the at least one guide. The at least one lateral extension may include a hook for engaging the at least one guide. Alternatively, the at least one lateral extension may include a wheel for engaging the at least one guide. Or, the at least one lateral extension may include a mechanical bearing for engaging the at least one guide. 
     In some embodiment, the ablation device includes at least one electrode formed on the electrode platform. The ablation device may further include a drive catheter extending proximally from the electrode platform. The electrode platform may be pivotable relative to the drive catheter. 
     In some embodiments, the angle relative to the central axis of the body may be between 30 degrees and 60 degrees. Or, the angle relative to the central axis of the body may be less than 30 degrees. 
     In some embodiments, the at least one guide may include a proximal portion parallel to the central axis of the body. The at least one guide may include a distal portion angled relative to the central axis of the body. The at least one guide may extend along at least a portion of the cover portion within the recess. 
     In some embodiments, the body includes an angled portion formed at an angle relative to the central axis of the body. The at least one guide may extend along the angled portion. 
     In some embodiments, the at least one guide includes a first portion extending at a first angle relative to the central axis of the body and a second portion extending at a second angle relative to the central axis of the body, the second angle being different than the first angle. 
     In some embodiments, the at least one guide may be a channel. Alternatively, the at least one guide may be a rail. The at least one guide may include a first guide and a second guide, the first guide and the second guide being parallel. 
     In some embodiments, the body may tubular. 
     The ablation device may include any one or more of the features listed above. 
     In another embodiment, a user interface of an ablation device includes a slot having a proximal end and a distal end, a trigger disposed in the slot, the trigger at least partially extending through the slot, and being movable between the proximal end and the distal end, and a drive catheter operatively coupled to the trigger, the drive catheter extending distally from the user interface and operatively coupled to an electrode platform. The slot may have a first portion and a second portion distal of the first portion, wherein when the trigger is in the first portion, the electrode platform is in a first orientation, and, wherein when the trigger is in the second portion, the electrode platform is in a second orientation, the second orientation being angled relative to the first orientation. 
     In some embodiments, the first portion and the second portion may be separated by a resistance mechanism configured to resist the movement of the trigger from the first portion to the second portion. 
     In some embodiments, the user interface further includes a third portion proximal the first portion, wherein the third portion and the first portion are separated by a resistance mechanism configured to resist the movement of the trigger from the third portion to the first portion. 
     The user interface may have any one or more of the features listed above. Additionally, the user interface may be used with any of the ablation devices described above. 
     In yet another embodiment, an ablation device system includes an endoscope having an imaging device for capturing images at a distal end of the endoscope, one or more lumens extending through at least a portion of the endoscope between a proximal end of the endoscope and the distal end, and, an ablation device according to any of the ablation devices described above. The ablation device system may further include a user interface as described 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 ablation cap, electrode platform, and drive catheter, in accordance with another embodiment of the present disclosure, illustrating the electrode platform in a partially extended position; 
         FIG.  13    is a perspective view of the ablation cap, electrode platform, and drive catheter shown in  FIG.  12   , illustrating the electrode platform in a fully extended, pivoted position; 
         FIG.  14    is a side view of the ablation cap, electrode platform, and drive catheter shown in  FIG.  12   , illustrating the electrode platform in a retracted position, comparable to that shown in  FIG.  1   ; 
         FIG.  15    is a cross-sectional side view of the ablation cap, electrode platform, and drive catheter shown in  FIG.  12   , with the electrode platform in a retracted position; 
         FIG.  16    is a cross-sectional side view of the ablation cap, electrode platform, and drive catheter shown in  FIG.  12   , with the electrode platform in a partially extended position, comparable to that shown in  FIG.  12   ; 
         FIG.  17    is a cross-sectional side view of the ablation cap, electrode platform, and drive catheter shown in  FIG.  12   , with the electrode platform in a fully extended, pivoted position, comparable to that shown in  FIG.  13   ; and, 
         FIGS.  18 A-C  are partial top views of a user interface for moving the electrode platform and drive catheter of  FIG.  12    between the positions illustrated in  FIGS.  12 - 17   . 
     
    
    
     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’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 . 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 or user interface  286  (see  FIGS.  18 A-C ). 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’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’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 - 17    illustrate another embodiment of an ablation cap, electrode platform, and drive catheter in accordance with the present disclosure. The ablation cap, electrode platform, and drive catheter of  FIGS.  12 - 17    may be used in conjunction with the endoscope  22  of  FIG.  11   , or other endoscopes. The structure of the ablation cap, electrode platform, and drive catheter of  FIGS.  1 - 11    is exemplary of the structures of the ablation cap, electrode platform, and drive catheter illustrated in  FIGS.  12 - 17   , except as described below. 
     Similar to prior embodiments,  FIGS.  12 - 17    illustrate an ablation cap  210  having a tubular body  212  having a lumen  214  formed therein. The ablation cap  210  includes a proximal portion  216  and a distal portion  218 . The proximal portion  216  of the cap  210  is sized to fit on a distal end  20  of an endoscope  22  (shown in  FIG.  11   ). In some embodiments, the proximal portion  216  of the ablation cap  210  may include a flexible portion that is connected to the tubular body  212  and that fits over the distal end  20  of the endoscope  22  to secure the cap  210  to the endoscope  22 , for example, by friction fit. In some embodiments, the proximal portion  216  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  218  of the ablation cap  210  may extend beyond the distal end  20  of the endoscope  22 . The distal portion  218  may form a generally cylindrical wall. However, unlike the ablation cap  10 , in the distal portion  218  of the ablation cap  210 , the tubular body  212  forms an angled portion  219 , providing for movement of an electrode platform in a direction of or toward the angled portion  219 . In some embodiments, the distal portion  218  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 nearby tissue to be treated by viewing the tissue through a wall of the distal portion  218  of the ablation cap  210 . The distal portion  218  may also include a portion that is formed from a material for magnifying the tissue under observation. 
     The cap  210  may further include a hood or a cover portion  229  that includes a recess  230  formed as part of the ablation cap  210 . The cover portion  229  may be integrally formed with the cap  210  or provided as a separate portion and connected to the cap  210 . The cover portion  229  is at least partially spaced apart from the tubular body to form the recess  230 . The recess  230  may be sized and shaped to hold an extendable electrode platform  234  within the recess  230  in a covered position, as shown in  FIGS.  14 - 15   , and comparable to the position illustrated in  FIG.  1   . The electrode platform  234  is slidably positionable within the recess  230  of the cover portion  229 . In some embodiments, the electrode platform  234  may be positioned entirely within the recess  230  of the cover portion  229  in the covered position so that electrodes positioned on the electrode platform  234  are completely covered. As shown in  FIG.  12   , the electrode platform  234  may be extended distally from the recess  230  so that at least a portion of a surface of the electrode platform is exposed and can contact the tissue to be treated. In some embodiments, the angled portion  219  is positioned below the electrode platform  234  when the electrode platform  234  is an exposed position and may be used to support the electrode platform  234  when the electrode platform  234  is pressed against the tissue to be treated. 
     In some embodiments, at least a portion of the electrode platform  234  may be viewable through the endoscope. The electrode platform  234  may move into and out of the view of the endoscope, for example, when the electrode platform  234  has been extended a certain percent relative to the cap f210, the electrode platform  234  may be viewed through the endoscope. By way of non-limiting example, the electrode platform  234  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.  15   . Electrodes positioned on the electrode platform  34  may also be energized when the electrode platform  34  is extended distally less than 100%. 
     As shown in  FIGS.  12 - 17   , the electrode platform  234  may be connected to a drive catheter  242  that extends proximally from the electrode platform  234 , through an opening (not shown) in the rear of the cover portion  239 , to a proximal control handle or user interface  286 , described below. In some embodiments, the drive catheter  234  may be connected to the dive catheter via a mechanical hinge, in order to allow the electrode platform to rotate or pivot relative to the drive catheter. In other embodiments, the electrode catheter may be connected to the drive catheter  242  via a living hinge, for example, formed by a flexible material, or a reduction in material. 
     The drive catheter  242  is distally movable to extend the electrode platform  234  from the recess  230  of the cover portion  229  and proximally movable to re-position the electrode platform  234  within the recess  230 . Typically, the electrode platform  234  is positioned within the recess  230  of the cover portion  229  when the ablation cap  210  is being delivered to a treatment site or being repositioned within a patient’s lumen for additional treatment at one or more additional sites. Positioning of the electrode platform  234  within the recess  230  also helps to prevent accidental energy delivery, for example to healthy tissue. The electrode platform  234  is at least partially distally extended from the recess  230  of the cover portion  229  for treatment at a site, and energy is delivered to the tissue to ablate the diseased tissue as described in more detail below. 
     The electrode platform  234  may include a support member upon which one or more electrodes  264  are positioned. The electrode platform  234 , and the one or more electrodes  264 , may be constructed and formed in the same manner as the electrode platform  34 , and the electrodes  64 , described above. Electrical wires  272  may extend through a lumen of the drive catheter  242  and connect to the electrodes  264  to supply the energy for ablation. Alternatively, the electrical wires  272  may extend through a lumen of the endoscope  22  . 
     In some embodiments, as described below, the electrode platform may include one or more lateral extensions  280  configured to slidably engage one or more guides  282  formed on the ablation cap  210 . The lateral extensions may be formed, for example, as wings (as shown), or as cylindrical rods. Notably, when the lateral extensions  280  are formed as cylindrical rods, the lateral extensions  280  and electrode platform  234  may rotate or pivot within the slot, about a central axis of the rods. 
     The ablation cap  210  differs from the ablation cap  10  in that it includes at least one guide  282  formed in the hood or cover portion  229 , and at least along a portion of the angled portion  219  of the tubular body  212 . In some embodiments, as shown, the ablation cap  210  includes two opposing guides  282 . The guides  282  may be formed as a channel, or a slot, formed in the cover portion  229 , and/or along the angled portion  219 , and are configured to receive the lateral extensions  280  of the electrode platform  282  in a sliding engagement. Notably, because the lateral extensions  280  are received within the guides  282 , the lateral extensions  280  are not exposed to tissue, thereby preventing an end or a portion of the lateral extensions  280  from catching onto any tissue, which could cause perforation of the tissue, when the electrode platform  234  and lateral extensions  280 , pivot in and/or slide along the guides  282 . In other embodiments, the guides  282  may be formed as a rail on which the lateral extensions are slidably mounted, for example, with a hook structure, a wheel, or other mechanical bearing. 
     The guides  282  may form multiple portions. For example, in a first portion formed within the hood or cover portion  229 , the guides  282  may extend in the proximal-distal direction, generally parallel to a central axis of the tubular body  212 . In a second portion formed along the angled portion  219 , the guides  282  may extend at an angle relative to the central axis of the tubular body  212  and/or the direction of the guides  282  formed in the cover portion  229 . In some embodiments, the guides  282  may transition from the first portion, extending in the proximal-distal direction, to the second portion, formed along the angled  219 , via a curved portion  284 . The curved portion may be configured to enable the lateral extensions  280  to slide within the guides  282  from the first portion to the second portion. In some embodiments, the guides  282  may extend along the angled portion  219  at an angle of 45 degrees relative to the central axis of the tubular body  212 . In other embodiments, the guides  282  may extend along the angled portion  219  at an angle of 30 to 60 degrees relative to the central axis of the tubular body  212 . In other embodiments, the guides  282  may extend along the angled portion  219  at an angle of less than 30 degrees relative to the central axis of the tubular body  212 . 
     In this way, as the electrode platform  234  is advanced via the drive catheter  242  distally from a retracted position, shown in  FIGS.  14 - 15   , to an exposed position, as shown in  FIG.  12   , the lateral extensions  280  slide in the guides  282  along the first portion formed in the hood  229  to guide the electrode platform  234 , and expose at least a portion of the one or more electrodes  264  formed on the electrode platform  234 . The electrodes  264  may be selectively energized to ablate tissue when the electrode platform  234  is advanced to the general position shown in  FIG.  12   . Or, as the electrode platform  234  is further advanced via the drive catheter  242  distal of the position shown in  FIG.  12   , the lateral extensions  280  slide in the guides  282  through the curved portion  284  and into the second portion, formed along the angled portion  219  of the tubular body  212 , as shown in  FIG.  13   , thereby guiding the electrode platform  234  (and electrodes  264  formed thereon) at an angle relative to the central axis of the tubular body  212 . In effect, the guides  282  cause the electrode platform  234  to rotate relative to the central axis of the tubular body  212  to the angle of the second portion. 
     In yet other embodiments, the guides  282  may extend along the angled portion  219  at multiple different angles relative to the central axis of the tubular body  212 . For example, the guides  282  may include a first portion formed within the hood or cover portion  229 , a second portion extending along the angled portion  219  at an angle of 30 degrees relative to the central axis of the tubular body  212 , and a third portion, distal of the second portion, extending along the angled portion  219  at an angle of 45 degrees relative to the central axis of the tubular body  212 . In yet other embodiments, the guides  282  may extend along the angled portion  219  through a range of gradually increasing angles relative to the central axis of the tubular body  212  to form a curved portion, where advancing the lateral extensions  280  distally through the curved portion of the guides  282  gradually increases the angle of the electrode platform  234  relative to the central axis of the tubular body  212 . 
     As described above, the ablation cap  210  and rotatable or pivotable electrode platform  234  provide a clinician with an ablation device having increased flexibility and maneuverability, thereby enabling a wider range of permissible treatment sites and applications, as compared to ablation devices having a rigid electrode platform and drive catheter. And, as with existing ablation devices, the ablation cap  210  may be attached to the distal end of an endoscope, permitting endoscopic visualization of the target tissue and ablation treatment, while providing the increased functionality described herein. 
     In some embodiments, the electrode platform  234  and drive catheter  242  may be coupled to a proximal control handle, or user interface. For example,  FIGS.  18 A-C  are partial top views of a proximal control handle or user interface  286  for moving the electrode platform  234  and drive catheter  242  between the positions illustrated in  FIGS.  12 - 17   . The user interface  286  may include a button or trigger  288  slidably mounted within a slot  290  and operatively coupled to the drive catheter  242 , such that movement of the trigger  288  results is movement of the drive catheter  242  (and electrode platform  234 ). The button or trigger  288  may extend from through the slot  290  for engagement with and movement by a finger of a user. 
     In some embodiments, the slot  290  may comprise a plurality of regions. For example, a first region  292  may be defined as a fully-retracted position, where the electrode platform  234  is fully retracted within the hood or cover portion  229  of the ablation cap  210 , as illustrated in  FIGS.  14 - 15   , and comparable to the position shown in  FIG.  1   . A second region  294  may be defined as an extended region, where the electrode platform  234  is at least partially extended from the hood or cover portion  229  of the ablation cap  210 , such that at least a portion of the electrodes  264  disposed thereon are exposed, and wherein the electrode platform  234  moves in the proximal-distal direction, without any rotation or pivoting, as illustrated in  FIGS.  12  and  16   . A third region  296  may be defined as a rotation or pivoting region, where entire the electrode platform  234  is extended beyond the hood or cover portion  229 , such that the electrodes  264  are fully exposed, and wherein the electrode platform  234  moves in the proximal-distal direction, but with rotation or pivoting, as illustrated in  FIGS.  13  and  17   . 
     In some embodiments, the slot  290  may have one or more locking and/or resistance mechanisms disposed therein to provide a user with tactile feedback and/or resist movement of the trigger  288  within the slot  290 . Suitable locking or resistance mechanisms may include protrusions, detents, frictional zones, narrowed slot width, or other suitable means. For example, a resistance mechanism may be associated with a proximal end of the first region  292 , corresponding to the fully retracted position of the electrode platform  234 , illustrated in  FIGS.  14  and  15   , such that movement of the trigger  288  from the first region  292  into the second region  294  requires the user to apply a threshold amount of force to the trigger  288  in the distal direction. Another resistance mechanism may be associated with a distal end of the second region  294 , corresponding to a fully extended position, without rotation or pivoting of the electrode platform  234 , illustrated in  FIG.  16   , such that further movement of the trigger  288  from the second region  294  into the third region  296  requires the user to apply a threshold amount of force to the trigger  288  in the distal direction. Movement of the trigger  288  to the distal end of the slot  290  in the third region  296  would then move and rotate or pivot the electrode platform  234  to the position illustrated in  FIGS.  13  and  17   , where the lateral extensions  280  of the electrode  234  have reached the distal end of the guides  282 . 
     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.