Patent Publication Number: US-2015088121-A1

Title: Ablation Overtube

Description:
RELATED APPLICATIONS 
     This application is a divisional application of U.S. application Ser. No. 13/209,763, filed Aug. 15, 2011 which claims the benefit of U.S. Provisional Application No. 61/378,732, filed Aug. 31, 2010, which are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     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 circumferentially oriented electrodes to endoscopically ablate the diseased tissue. Typically, the circumferentially oriented electrodes are positioned on an inflatable balloon. The balloon must be inflated to a predetermined size to achieve adequate contact with the diseased tissue for delivery of the appropriate amount of energy from the bipolar ablation device to ablate the diseased tissue. In order to determine the correct size and balloon pressure to achieve adequate ablation, a sizing balloon must first be introduced into the esophagus. Once the proper measurements are made with the sizing balloon, the treatment device can then be endoscopically inserted into the patient&#39;s esophagus. The balloon inflated treatment device and procedure requires an additional step to size the balloon and adds more time and potential patient discomfort to the treatment procedure. In addition, the inflated balloon is positioned in front of the endoscope viewing window, preventing direct visualization of the target tissue and potentially leading to ablation of healthy tissue or incomplete ablation of diseased tissue. 
     What is needed in the art is an ablation treatment device that is simple to use, that minimizes the number of steps in a treatment procedure and that provides treatment under direct endoscopic visualization. 
     BRIEF SUMMARY 
     Accordingly, it is an object of the present invention to provide a device and a method having features that resolve or improve on one or more of the above-described drawbacks. 
     In one aspect of the present invention, an energy delivery system is provided. The energy delivery system includes an overtube. The overtube includes a body having a proximal portion, a distal portion and a lumen extending at least partially therethrough. The proximal portion is adapted to be positioned over a distal portion of an endoscope. The body also includes a plurality of openings formed in the body and connected to the lumen and an electrode operably connected to the body and extending over at least a portion of a surface of the body. The lumen is operably connectable to a vacuum source and the electrode is operably connectable to a power source. 
     In another aspect of the present invention, a method of delivering energy to a tissue site within a patient&#39;s lumen is provided. The method includes positioning an energy delivery system within a patient&#39;s lumen. The energy delivery system includes an overtube having a body including a proximal portion, a distal portion and a lumen extending at least partially therethrough. The overtube also includes a plurality of openings formed in the body and connected to the lumen; and an electrode operably connected to the body and extending over at least a portion of a surface of the body. The method further includes applying suction to the plurality of openings, drawing the tissue site to be treated to the body using suction and applying energy to the tissue site. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an ablation overtube in accordance with an embodiment of the present invention; 
         FIG. 2A  is partial sectional view of the ablation overtube shown in  FIG. 1  positioned over an endoscope; 
         FIG. 2B  is a cross-sectional view across B-B shown in  FIG. 2A ; 
         FIG. 3  is a partial view of electrodes in accordance with an embodiment of the present invention; 
         FIG. 4A  is a side view of an embodiment of an ablation overtube with a moveable member in a first position; 
         FIG. 4B  is a side view of the embodiment of the ablation overtube shown in  FIG. 4A  with a moveable member in a second position; 
         FIG. 4C  is a cross-sectional view across C-C shown in  FIG. 4A ; 
         FIG. 5A  is a sectional view of an alternative embodiment of an ablation overtube in accordance with the present invention; 
         FIG. 5B  is a sectional view of the embodiment shown in  FIG. 5A ; 
         FIG. 6  is a view of an embodiment of an ablation overtube and an endoscope; and 
         FIGS. 7A-7B  illustrate operation of the ablation overtube. 
     
    
    
     DETAILED DESCRIPTION 
     The invention is described with reference to the drawings in which like elements are referred to by like numerals. The relationship and functioning of the various elements of this invention are better understood by the following detailed description. However, the embodiments of this invention are not limited to the embodiments illustrated in the drawings. It should be understood that the drawings are not to scale, and in certain instances details have been omitted which are not necessary for an understanding of the present invention, such as conventional fabrication and assembly. 
     As used in the specification, the terms proximal and distal should be understood as being in the terms of a physician delivering the stent to a patient. Hence the term “distal” means the portion of the ablation overtube that is farthest from the physician and the term “proximal” means the portion of the ablation overtube that is nearest to the physician. 
       FIG. 1  illustrates an embodiment of an ablation overtube  10  in accordance with the present invention. As shown in  FIG. 2A , the ablation overtube  10  includes a tubular body  12  having a lumen  14  formed therein. The lumen  14  of the body  12  is sized to fit over a distal end  18  of a conventional endoscope  20 . A cross sectional view of the endoscope  20  and the overtube  10  is shown in  FIG. 2B . The overtube  10  has a length suitable for accessing the desired target tissue, but is generally shorter than the working length of the endoscope  20 . As shown in  FIG. 2B , the endoscope  20  includes a plurality of lumens  26  formed therein that may be used as a working channel, a viewing port for a viewing device, a flush port, a wire guide port and the like. 
     A distal end portion  32  of the overtube  10  is shown in  FIG. 1  and includes a curvilinear distal end  34 . The distal end  34  is shaped for non-traumatic delivery through the patient&#39;s lumen and may be domed, conical, oval and the like. A plurality of openings  36  are also provided on the distal end portion  32 . The openings  36  are used for suctioning the tissue into proximity to the ablation overtube  10 . The openings  36  may also be used for fluid delivery or additional separate openings may be provided to deliver fluid to the tissue during ablation. The plurality of openings  36  may include at least one first opening  38  and at least one second opening  42 . As shown in  FIG. 1 , the first openings  38  are larger than second openings  42 . In some embodiments, the openings  36  may all be similarly sized or the first openings  38  may be smaller than the second openings  42 . A first plurality  48  of first openings  38  may be positioned circumferentially around the distal portion  32  of the overtube  10 . By way of non-limiting example, the first plurality  48  of first openings  38  may include openings  38  that are positioned on the body  12  and spaced apart by 180°, 90°, or any other suitable spacing. Other positions for the first plurality  48  of the openings  38  may also be used and may be asymmetrically or symmetrically positioned around the overtube  10 . Two, three or more first openings  38  may be included in the first plurality  48 . 
     A second plurality  52  of first openings  38  may also be included on the distal portion  32  of the overtube  10  and positioned proximal to the first plurality  48  of first openings  38 . The positioning of the second plurality  52  of first openings  38  may be the same as the first plurality  48 , or may be different in number, in spacing or in both. As shown in  FIG. 1 , and by way of non-limiting example, the second openings  42  extend longitudinally in a row  54  on the distal portion  32  of the overtube  10 . A plurality of longitudinal rows  54  of second openings  42  may be positioned circumferentially around the distal portion  32 . As shown in  FIG. 1 , a pair of rows  54  of second openings  42  may be provided next to each other. In some embodiments, the rows  54  may be spaced apart by 180°, 90°, or any other suitable spacing. The second openings  42  may also extend in rows spiraling around the distal portion  42 , in a zig zag pattern or in other patterns on the distal portion  32  of the overtube  10 . Openings  36  on different portions of the ablation overtube  10  may be activated independently depending on how much tissue is to drawn to the overtube  10  and ablated. 
     The distal portion  32  of the ablation overtube  10  also includes at least one electrode  44  or a plurality of electrodes  44  as shown in  FIG. 1 . The electrodes  44  are shown as a plurality of circumferentially extending bands  46  substantially encircling the distal portion  32  of the ablation overtube  10 . In some embodiments, the electrodes  44  may extend about 3 mm to about 90 mm longitudinally along the distal portion  32  of the overtube  10 . As shown in  FIG. 1 , the electrodes  44  extend between the first and second plurality  48 ,  52  of first openings  38 . The pattern of the electrodes  44  may include substantially circumferential bands having a plurality of bands adjacent to each other, a plurality of longitudinally extending strips, extending between the proximal openings  52  and the distal openings  48 , angled or helical patterns, circular patterns or any other pattern suitable for ablation of the target tissue. By way of non-limiting example, if the electrodes  44  cover an area about 360° around an ablation overtube, a section of 180° may be independently activated from the remaining 180° electrode section. Alternatively, electrodes may be provided to cover, 45°, 90°, 180° or other section sizes on the ablation overtube  10 . 
     As shown in  FIGS. 1 and 3 , the electrodes  44  may be provided in pairs to form a bipolar delivery device. One electrode  44  of the pair is a positive electrode and other electrode  44  of the pair is a negative electrode. The positive and negative electrodes  44  alternate in the pattern as shown in  FIG. 3 . Distance  47  between the electrodes  44  may be optimized to control the depth of ablation of the target tissue. The distance  47  between positive and negative electrodes  44  may be between about 0.05 mm and about 5 mm, but is not limited to these distances. In some embodiments, the electrodes  44  may cover a portion of the ablation overtube  10  or be selectively energizable so that only a portion of the ablation overtube contacting the tissue to be treated is activated. By way of non-limiting example, the electrodes  44  may be selectively energizable in a portion extending 360° around the overtube  10  and may extend for a length of about 1-100 mm although greater lengths may also be used. Non-limiting examples of selective activation could include an energizable portion extending 360° around the overtube  10  and extending longitudinally about 6 cm, or in a portion extending 360° and extending longitudinally about 1 cm, 10 cm, 20 cm, etc. or in a portion extending about 90° and extending longitudinally about 1, 2, 10, 20 or 50 cm. Other activation configurations for selectively energizing portions of the electrodes 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 like. 
     In some embodiments, one or more electrodes  44  may be provided as a monopolar delivery device and may include a grounding pad or an impedance circuit (not shown). As shown in  FIG. 1 , the second openings  42  are co-extensive with the electrodes  44  so that the tissue may be suctioned onto the electrodes for ablation. The electrodes  44  connect to a power source  310  shown in  FIG. 6  to supply energy to the electrodes  44  to ablate the tissue when suction is applied to the openings  36  to pull the tissue to the ablation overtube  10 . The power source may be any suitable source for delivering power for a surgical procedure. The power source  310  may be a radio frequency source. However, other types of power sources may also be used to provide energy to the electrodes  44 . By way of non-limiting example, additional possible energy sources may include microwave, ultraviolet and laser energies. 
       FIGS. 4A and 4B  illustrate an alternative embodiment of an ablation overtube  100  in accordance with the present invention. The ablation overtube  100  includes a tubular body  112  having a lumen  114  formed therein. Similar to the ablation overtube  10  described above, the lumen  114  of the body  112  is sized to fit over a distal end  18  of a conventional endoscope  20 . A distal end portion  132  of the overtube  100  is shown in  FIGS. 4A and 4B  and includes a curvilinear distal end  134 . The distal end  134  is shaped for non-traumatic delivery through the patient&#39;s lumen and may be domed, conical, oval and the like. A plurality of openings  136  are also provided on the distal end portion  132 . The openings  136  are used for suctioning the tissue into proximity to the ablation overtube  100 . The openings  136  may also be used for fluid delivery or additional separate openings may be provided to deliver fluid to the tissue during ablation. The plurality of openings  136  may include at least one first opening  138  and at least one second opening  142 . As shown in  FIG. 4A , the first openings  138  are larger than second openings  142 . In some embodiments, the openings  136  may all be similarly sized or the first openings  138  may be smaller than the second openings  142 . A first plurality  148  of first openings  138  may be positioned circumferentially around the distal portion  132  of the overtube  100 . By way of non-limiting example, the first plurality  148  of first openings  138  may include openings  138  that are positioned on the body  112  and spaced apart by 180°, 90°, or any other suitable spacing. Other positions for the first plurality  148  of the openings  138  may also be used and may be asymmetrically or symmetrically placed. Two, three or more first openings  138  may be included in the first plurality  148 . 
     A second plurality  152  of first openings  138  may also be included on the distal portion  132  of the overtube  100  and positioned proximal to the first plurality  148  of first openings  138 . The positioning of the second plurality  152  of first openings  138  may be the same as the first plurality  148 , or may be different in number, in spacing or in both. As shown in  FIGS. 4A and 4B , and by way of non-limiting example, the second openings  142  extend longitudinally in a row  154  on the distal portion  132  of the overtube  100 . A plurality of longitudinal rows  154  of second openings  142  may be positioned circumferentially around the distal portion  132 , by way of non-limiting example the rows  154  may be spaced apart by 180°, 90°, or any other suitable spacing. The second openings  142  may also extend in rows spiraling around the distal portion  132 , in a zig zag pattern or in other patterns on the distal portion  132  of the overtube  100 . 
     The distal portion  132  of the ablation overtube  100  also includes at least one electrode  164  or a plurality of electrodes  164 . The electrodes  164  may be provided in pairs for a bipolar device or individually for a monopolar device as described above with reference to electrodes  44 . As shown in  FIGS. 4A and 4B , the electrodes  164  are positioned on a movable member  166 . The movable member  166  is slidably positionable on the distal portion  132  of the overtube  100 . The moveable member  166  may be moved proximally and distally along the distal portion  132  to move the electrodes  164  proximally and distally. The ablation overtube  100  may further include one or more drive cables  168  connecting to the movable member  166  and extending proximally so that the operator can control the movement of the movable member  166 . One or more guiding wires  170  may also be provided and connected to the movable member  166 . The guiding wires  170  extend proximally to facilitate control of the movement of the movable member  166  by the operator so that the movable member  166  does not rotate if undesired. The drive cables  168  and/or the guide wires  170  may be connected to a power source  310  connected to the endoscope  20  as shown in  FIG. 6  to supply energy to the electrodes  164  to ablate the tissue. The electrodes  164  are shown as a plurality of circumferential bands substantially encircling the movable member  166 . Similar to the electrodes  44  described above, the pattern of the electrodes  164  may be any pattern suitable for ablation and the bands are shown by way of non-limiting example. In some embodiments, the electrodes  164  may extend about 3 mm to about 30 mm longitudinally along the movable member  166 , but are not limited to these distances. Similar to the electrodes  44  described above, the electrodes  164  may be selectively activatable so that a portion of the electrodes  164  are activated and a portion of the electrodes  164  are not energized. As shown in  FIG. 4A , the moveable member  166  and the electrodes  164  are at a first position  172  on the distal portion  132  of the overtube  100 .  FIG. 4B  illustrates the movable member  166  and the electrodes  164  at a second position  174  on the distal portion  132  of the overtube  100  that is proximal to the first position  172 . The moveable member  166  and the electrodes  164  may be positioned anywhere along the distal portion  132  of the ablation overtube  100  to allow the physician to deliver a precise ablation energy to the target tissue and to reposition the electrodes  164  at another site directly adjacent to or close to the first site as described in more detail below. In some embodiments, the moveable member  166  extends between the first and second plurality  148 ,  152  of first openings  138 . The second openings  142  may be positioned along the path of the moveable member  166  so that the tissue may be suctioned to the distal portion  132  of the body  112  and onto the electrodes  164  at any position of the movable member  166 . As shown in  FIGS. 4A and 4B , the movable member does not extend beyond the distal end  134 . 
     The overtube  100  may further include one or more sheaths  178  that are positioned over the body  112  and sized and shaped to receive the movable member  166  therein. As shown in  FIG. 4B , the sheath  178  may be positioned at a distal position  180  and/or at a proximal position  182  so that the movable member  166  and the electrodes  164  may be slidably positioned between the sheath  178  and the body  112  of the overtube  110 . The sheath  178  may be sized to receive the drive cables  168  and the guiding wires  170  therein. The sheath  178  may also be sized to closely fit over the moveable member  166  to remove any tissue remnants that adhere to the movable member  166  after ablation of the tissue by slidably moving the movable member  166  into the sheath  178 . 
     Flush ports  184  may also be provided in the body  112  for flushing the tissue and the electrodes  164 . The flush ports  184  may be alternated with the openings  136  provided for suctioning the tissue to the ablation overtube  100 . In some embodiments, the body  112  may be provided with separate lumens connecting to the flush ports  184  and the openings  136 . A cross-sectional view of the overtube  100  is shown in  FIG. 4C . The body  112  includes the lumen  114  that receives the endoscope  20  (similar to the arrangement shown in  FIG. 2A ). In some embodiments, the lumen  114  may extend to the distal end  134  so that a wire guide (not shown) may extend therethrough to facilitate placement of the ablation overtube  100 . One or more flushing lumens  186  are provided for connection to the flush ports  184  and a fluid source. One or more suction lumens  188  are provided for connection to the openings  136  and a suction source connectable to the endoscope  20  at the port  312  (see  FIG. 6 ). The drive cables  168  and guiding wires  170  are also shown. 
       FIGS. 5A and 5B  illustrate an alternative embodiment of an ablation overtube  200  in accordance with the present invention. The ablation overtube  200  includes a tubular body  212  having a lumen  214  formed therein. Similar to the ablation overtube  10  described above, the lumen  214  of the body  212  is sized to fit over a distal end  18  of a conventional endoscope  20 . A distal end portion  232  of the overtube  200  is shown in  FIGS. 5A and 5B . The distal end  234  may be open as shown, or closed and/or curvilinear. A plurality of openings  236  may be provided on the distal end portion  232 . Similar to the openings  36  described above, the openings  236  are used for suctioning the tissue into proximity to the ablation overtube  200 . The openings  236  may also be used for fluid delivery or additional separate openings may be provided to deliver fluid to the tissue during ablation. The openings  236  may be provided in different sizes and different patterns as described above. The distal portion  232  of the ablation overtube  200  also includes at least one electrode  265  or a plurality of electrodes  265 . As shown in  FIGS. 5A and 5B , the electrodes  265  are positioned on the distal portion  232  of the body  212 . The electrodes  265  may be provided in any suitable pattern on the body  212 , including a plurality of rings, spirals or geometric patterns. Similar to the electrodes  44  described above, the electrodes  265  may be selectively activatable so that a portion of the electrodes  265  are activated and a portion of the electrodes  265  are not energized. 
     The ablation overtube  200  may also include a movable member  267  that is slidably positionable within the lumen  214  of the body  212  of the overtube  200 . The moveable member  267  may be moved proximally and distally within the lumen  214 . The movable member  267  may be provided with an energy source  269  to transfer energy to the electrodes  265  for tissue ablation. For example, the energy source  269  may be a magnet that is activatable by the physician. The magnet can be rotated about a fixed axis to induce a current to transfer energy to the electrodes  265 . By way of another non-limiting example, the energy source  269  may be activatable to provide thermal energy that is transferable to the electrodes  265  for tissue ablation. Shielding members  274  may be provided to shield the energy source  269  and to limit the dissipation of energy from the energy source  269  to only the targeted tissue. The energy source  269  and the shielding  274  may be connected to one or more drive cables  268  that may extend through the lumen  214  of the overtube  200  and through the endoscope  20  so the user can control the movement of the energy source  269  proximally and distally and to provide connection to a power source  310 . 
     As shown in  FIG. 5A , the moveable member  267  is shown at a first position  272  within the distal portion  232  of the overtube  200 . The electrodes  265  that are activatable by the energy source  269  with the moveable member  267  in the first position  272  are indicated by a first region  273  on the body  212 .  FIG. 5B  illustrates the movable member  267  and the electrodes  164  at a second position  174  on the distal portion  132  of the overtube  100  that is proximal to the first position  172 . The moveable member  166  and the electrodes  164  may be positioned anywhere along the distal portion  132  of the ablation overtube  100  to allow the physician to deliver a precise ablation energy to the target tissue and to reposition the electrodes  164  at another site directly adjacent to or close to the first site as described in more detail below. In some embodiments, the moveable member  166  extends between the first and second plurality  148 ,  152  of first openings  138 . The second openings  142  may be positioned along the path of the moveable member  166  so that the tissue may be suctioned to the distal portion  132  of the body  112  and onto the electrodes  164  at any position of the movable member  166 . 
     The endoscope  20  is shown in  FIG. 6  with the ablation overtube  10  positioned over the distal end  18  of the endoscope  20 . The overtube  10  is shown by way of non-limiting example and the other embodiments of the ablation overtube may also be similarly positioned over the distal end  18  of the endoscope  20 . The endoscope  20  may include a suction port  312  for connecting to a suction source to provide the suction to pull the tissue to the ablation overtube  10 . The endoscope  20  may also include a flush port  314 , a working channel  316  and a video control portion  318 . 
     In some embodiments, the ablation overtube is 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 overtube or a distal portion of the ablation overtube is 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. The ablation overtube 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. 
     The electrodes may be secured to the body of the ablation overtube by any method know 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. 
     Operation of the ablation device using the ablation overtube  10  as an example will be explained with reference to  FIGS. 7A-7C .  FIG. 7A  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 overtube  10 .  FIG. 7B  illustrates the distal portion  34  of the ablation overtube  10  positioned over the endoscope  20  and the overtube  10  and the endoscope  20  being inserted into the patient&#39;s esophagus  80 . The ablation overtube  10  is positioned in the esophagus  80  near the portion of the diseased tissue  84  to be treated. The insertion of the ablation overtube  10  may be monitored using the viewing port of the endoscope to help position the overtube  10  at the diseased tissue. As shown in  FIG. 7C , the diseased tissue  84  has been pulled to the ablation overtube  10  using the vacuum pulled through one or more of the openings  36  in the ablation overtube  10 . The diseased tissue has been brought into contact with the electrodes  44  or an electroconductive fluid flushed through one or more of the openings  36 . The power source  310  is activated for a sufficient time to ablate the diseased tissue  84 . The vacuum is released and the ablation overtube is moved away from the tissue  84 . The overtube  10  may be rinsed through the openings  36  to move any adherent tissue. The ablation overtube  10  may be repositioned near another portion of diseased tissue  84  for treatment and the steps repeated as many times as needed. While the procedure has been described with reference to the ablation of diseased tissue in the esophagus using the ablation overtube  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 overtube  10 . 
     The above Figures and disclosure are intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in the art. All such variations and alternatives are intended to be encompassed within the scope of the attached claims. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the attached claims.