Abstract:
An obesity treatment device comprises a filament filler material movable between a substantially straight insertion/removal configuration and an operative configuration in which the filament extends along a predetermined curve to occupy a selected volume within the stomach and a retrieval device connected to a proximal end of the filler material facilitating grasping and withdrawal of the filler material. A method of treating obesity, comprises inserting to a desired position within the GI tract a filament filler in a substantially straight configuration and moving the filler into an operative configuration in which the filler curves along a predetermined path to define a desired volume in combination with, after a predetermined treatment period has elapsed, collapsing the filler into the substantially straight configuration for trans-oral removal.

Description:
PRIORITY CLAIM 
       [0001]    This application claims the priority to the U.S. Provisional Application Ser. No. 60/910,356, entitled “GASTRIC FILLER DEVICES FOR OBESITY THERAPY” filed Apr. 5, 2007. The specification of the above-identified application is incorporated herewith by reference. 
     
    
     BACKGROUND 
       [0002]    The incidence of obesity is rapidly increasing in industrialized countries and methods and procedures to control the weight of obese individuals is receiving ever increasing attention. In addition to diets and other lifestyle changes, aggressive medical procedures are available to limit caloric intake. Many procedures limit the amount of food digested by, for example, blocking or bypassing portions of the gastro intestinal (GI) tract. Other procedures focus on generating feelings of satiety after ingestion of reduced quantities of food. 
         [0003]    One such treatment involves placing a filler material within the stomach, often through the esophagus. The filler material takes up room in the stomach, generating a feeling of satiety and reducing the desire to eat. The material also restricts and slows the passage of food through the stomach into the intestines, extending the duration of the feeling of satiety and the reduced desire to eat. 
         [0004]    One type of filler includes gas filled bubbles which float upward and apply pressure on the greater curvature of the stomach wall. This pressure is sensed by baro-receptors in the greater curvature which send a signal to the brain indicating that the stomach is full. Fluid filled and other non-floating filling devices apply a downward force to the stomach wall which also generates feelings of satiety. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is directed to a gastric fill device comprising a conduit having a lumen with a distal end insertable in the stomach and a proximal end accessible externally, a filler material having a substantially straight string-like configuration used for insertion and for removal from the stomach, and an expanded operative configuration to occupy a selected volume within the stomach, and a retrieval element operatively connected to the filler material for grasping and withdrawing the filler material. 
         [0006]    In another aspect, the present invention is directed to an obesity treatment device comprising filament filler material movable between a substantially straight insertion/removal configuration and an operative configuration in which the filament extends along one or more curves to occupy a selected volume within the stomach and a retrieval element connected to a proximal end of the filler material facilitating grasping and withdrawal of the filler material. 
         [0007]    The present invention is further directed to a method of treating obesity comprising inserting to a desired position within the GI tract a filament filler in a substantially straight configuration and moving the filler into an operative configuration in which the filler curves to define a desired volume in combination with, after a predetermined treatment period has elapsed, collapsing the filler into the substantially straight configuration for trans-oral removal. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1  shows a diagram of a first embodiment of a gastric filler according to the invention; 
           [0009]      FIG. 2  shows a second embodiment of a gastric filler according to the invention; 
           [0010]      FIG. 3  shows a diagram of a third embodiment of a gastric filler placed within the stomach; and 
           [0011]      FIG. 4  shows an embodiment of a delivery and retrieval system for a gastric filler according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The present invention may be further understood with reference to the following description and to the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to devices and methods for treating obesity specifically, by partially filling a gastric space. More specifically, the present invention relates to the insertion and removal of gastric space filling devices which has previously proven difficult. 
         [0013]    The methods and devices according to the present invention provide devices and methods for more easily deploying and removing space filling devices from the stomach and the upper GI tract. That is, after a predetermined time period has elapsed during which physical limiting of caloric intake is desired, it is preferable to remove the gastric filler from the stomach. However, removal of known gastric fillers has proven difficult for a variety of reasons. Embodiments according to the invention also provide novel space filling technologies and products that may be used as gastric fillers or as fillers in other body spaces designed to facilitate the insertion and removal procedures. 
         [0014]    An exemplary gastric filler according to a first embodiment of the invention includes a gastric bubble formed with an integrated deflation and retrieval mechanism simplifying removal of the bubble after the desired treatment period has elapsed. The gastric bubble comprises a shell-like body formed of a polymeric wall including a failure zone pre-formed in the wall during a molding or other manufacturing operation as, for example, a weakening groove or indentation. The body may be a single filling volume or a series of filling volumes that are either independently or simultaneously fillable. As will be described in more detail below, during removal, the wall is torn along the weakening groove by the removal force, such that the balloon unwinds into an elongated strip that can be easily removed trans-orally. The gastric bubble may be inflated through a self sealing valve mechanism that seals itself when an inflation device (e.g., an inflation tube or catheter) is withdrawn from the valve. The valve may comprise any self sealing valve known to those skilled in the art, such as a basketball valve, a duckbill valve, etc. The bubble may be inflated using air or, alternatively, an inert gas or mixture of gases of predetermined density. In another embodiment, the bubble may be self expanded through a chemical and/or physical reaction with contents of the stomach. For example, the bubble may be inserted in an unexpanded state and upon delivery, may enter an expanded state by absorbing stomach fluids. 
         [0015]      FIG. 1  shows an exemplary embodiment of a gastric balloon  100  including an outer wall  104  with a failure zone formed as a groove  106  extending around the wall  104  in a spiral. Those skilled in the art will understand that the failure zone is formed so that a strength of the wall  104  in this area is reduced with respect to the rest of the wall  104  (e.g., by thinning this portion of the wall) so that, when subject to a predetermined stress, the wall  104  will separate along the groove  106 . A tag with a loop  102 , or other retrieval element, is connected to one end of the gastric balloon  100  so that it may be grasped and pulled by the physician with a grasping instrument, for example, under direct visualization using an endoscope to apply the predetermined stress to the failure zone. When it is desired to remove the gastric balloon  100  from a portion of the GI tract into which it has been inserted, the user locates the tag  102  (e.g., under direct visualization via an endoscope) and manipulates a grasping device to apply tension to the balloon  100  to cause an initial break of the material forming the wall  104  along the groove  106 . As the application of tension is continued, the wall  104  unravels into a long piece of tape  110  which is removed as the grasping device is withdrawn through the esophagus and the mouth or which is drawn with the grasping device into the working channel of the endoscope which is then withdrawn trans-orally. In the exemplary embodiment shown in  FIG. 1 , the balloon  100  has a substantially spherical shape. However, other embodiments may include other geometries, such as cones, cylinders, elliptical shapes, etc. 
         [0016]    As shown in  FIG. 2 , a gastric balloon  200  according to a second embodiment of the invention includes a net or bag  204  which, after insertion into a desired portion of the GI tract (e.g., the stomach), is filled with a filler material until the balloon  200  takes up a desired volume. The filler material preferably comprises string or a similar material easily inserted into and removed from the GI tract via the mouth. The net  204  includes a tether end  202  which is coupled to the filler material to facilitate grasping by a retrieval device inserted via an endoscope for removal of the filler material from the body. The net  204  may be formed as a porous netting or a fluid/gas barrier depending on a degree of desired interactivity between the stomach contents and the balloon  200 . A higher degree of porosity may result in faster transport of materials through the stomach while a lower porosity may impede material transport. The net  204  may include one or more preformed failure zones. For example, the net  204  may be woven or crocheted so as to unravel when pulled. In some embodiments, portions of the net  204  and/or the filler material may be biodegradable or dissolvable. For instance, the net  204  may be dissolvable by application of a solvent, a dissolving solution or heat, or may be designed to dissolve after a predetermined period of time after exposure to stomach fluids (e.g., three months). Once the net  204  is dissolved or manually broken, the filler material may be exposed to the same or another dissolving agent, and may be absorbed or passed through the digestive system. 
         [0017]    The filler material in this exemplary filler balloon  200  is formed as a length of string  206  coupled to the tether end  202 . The string  206  is inserted into the net  204  via an opening  212  after the bag  204  has been placed in the stomach or other desired location within the GI tract. As an alternative to or in addition to the string  206 , other filler materials, such as hydrogels, beads, absorbable elements, etc., may be used to give the desired volume to the net  204 . The filler material may also have a specified geometry that facilitates deployment, filling or removal of the balloon  200 . Exemplary geometries include dimpled or porous surfaces and variable sized or shaped elements. 
         [0018]    Both the string  206  and the bag net  204  may be inserted using endoscopic instruments and procedures allowing the trans-oral insertion and removal of these gastric filling devices to be accomplished easily and rapidly. As described above, the string-like filler material may be grasped at one end, such as by an end  210  attached to the tether  202 , and pulled out through the esophagus and the mouth. The bag or net  204 , once deflated by removing the filler material, may then be pulled out through the esophagus and mouth in the same manner described above for the string-like filler material. The string  206  may also be coupled to the bag  204  to facilitate removal of the bag  204  after the string  206  is removed. Thus, removal of both the string  206  and the bag  204  may be performed in a single step. In another embodiment, the tether  202  may comprise a ripcord coupled to the bag  204 . That is, the tether  202  may perform a tearing or opening function. In an embodiment where the bag  204  comprises multiple filling volumes, the tether  202  may separate the multiple volumes and/or individually open or tear each volume separately as would be understood by those skilled in the art. 
         [0019]    In a different embodiment according to the invention, the gastric fill material comprises a stand-alone filling device placed within the stomach without a constraining element such as a net or a bag. The filling device may comprise any shape that provides a desired filling characteristic. For example, the filling device may be shaped to fill a portion of the antrum (e.g., tapered, conical, etc.), thereby slowing gastric emptying. Exemplary filling device shapes include open coils, S-ribbons, stars, shapes with wide and/or irregular cross-sections, etc. The filling device may be formed of any biocompatible elastic material, such as stainless steel, platinum, titanium, a polymer, etc. In another embodiment, the filling device may comprise a shape memory material such as Nitinol and other materials used in the manufacture of embolic coils for treating aneurisms. The filling device may be inserted or removed through a working channel of an endoscope/delivery tube in a substantially low profile and deformed using any combination of mechanical, electrical or chemical techniques. Alternatively, the filling device may be delivered while wrapped around an exterior of the endoscope/delivery tube. In some embodiments, the filling device may be deformed using electricity, temperature change, a physical or chemical reaction (e.g., absorption of fluids), manual manipulation, etc. The deformation may be in multiple dimensions (e.g., three-dimensional expansion, two-dimensional torsion, etc.). In some embodiments, the deformation may be reversible so that the filling device may be withdrawn while maintaining the low profile. 
         [0020]    In another embodiment, the stand-alone filling device may be formed of an interwoven material comprising a three-dimensional mesh or nest. A weaving pattern may be selected to facilitate insertion and removal of the filling device, or to regulate the transport of material through the stomach. The mesh may be woven into any number of shapes, such as those described above with reference to the stand-alone device (e.g., cones, stars, irregular patterns, curved patterns, etc.). 
         [0021]      FIG. 3  shows an exemplary embodiment of a gastric filling device  300  comprising a coil  310  which is deployed into the stomach  302  via an endoscope or other tubular device inserted through the mouth and esophagus  304 . The lower esophageal sphincter (“LES”) and the esophagus  304  are protected from damage or irritation by maintaining the coil  310  within the working channel of an endoscope during insertion and removal of the coil  310  therethrough. Additionally, some patients may have feeding tubes, such as a percutaneous endoscopic gastrostomy (PEG) tube placed through an oral cavity or percutaneously (e.g., through an abdominal stoma). In such instances, the feeding tube may function as a delivery and/or removal device for the filling device  300 . 
         [0022]    The coil  310  may be formed of a shape memory material. As would be understood by those skilled in the art, the shape memory properties of the coil  310  allow the coil  310  to be maintained in a substantially straight shape during insertion through the working channel of the endoscope with the material reverting to a memorized coil shape after deployment within the stomach  302 . Thus, the substantially straight shape facilitates trans-oral insertion while the shape memory properties of the coil  310  allow it to expand to a pre-selected shape and volume without the need for a separate constraining device such as the bag, net or bubbles described above. As with the above-described embodiments, the operative shape and volume are selected so that, when in a desired position within the stomach  302 , the volume taken and/or the stimulation applied to the wall of the stomach  302  enhances feelings of satiety. For example, the material of the coil  310  may be formed to take the form of a sphere or other hollow shell geometry after it has been deployed in the stomach  302 . After completion of the treatment, the coil  310  may be returned to its substantially straight shape to be removed by, for example, grasping a proximal end of the coil  310  and drawing the coil into the working channel of an endoscope. The force of pulling into the endoscope causes the coil  310  to straighten. Alternatively, in other embodiments, the shape change may be caused by a stimulus such as an electrical signal, a chemical or physical reaction (e.g., absorption of fluid), etc. 
         [0023]    In another embodiment, the coil  310  may be formed of an elastic material without shape memory, but with sufficient malleability so as to retain shape after being manually deformed. Alternatively, the elastic material may be biased towards the straight, low profile configuration, deforming to accommodate a natural curvature of the stomach wall. 
         [0024]    The embodiments of the gastric filler according to the invention described above may be deployed and retrieved using conventional techniques, such as endoscopic procedures. However, improved devices to manipulate the gastric filling devices are within the scope of the invention. The improved methods and devices may be used in conjunction with the gastric filling devices described above, as well as with conventional gastric balloons and bubbles used for the treatment of obesity. 
         [0025]    In one exemplary embodiment, access to the stomach of a patient may be provided by a catheter placed through the esophagus. A stent-like device is inserted through the catheter trans-orally in a compact configuration, such as folded unto itself. Once placed in the stomach, the device opens up like a stent, and takes up a selected volume within the stomach. This gives to the patient a feeling of satiety or fullness, so that less food is ingested. For example, the catheter may be a AAA stent-graft marketed by Trivascular and Boston Scientific Corporation, of Natick, Mass. The stent may comprise any number of shapes, including a cylinder, a ball and a torpedo. The stent is free floating in the stomach and may be sized to produce a desired amount of satiety. 
         [0026]    In another exemplary embodiment, the delivery and retrieval system used for a gastric filling device utilizes a flexible overtube inserted into the GI tract and advanced until a distal end reaches a desired position within the stomach. At this point, a shape of the overtube may be locked so that forces applied to the overtube via devices inserted and/or withdrawn therethrough are absorbed by the overtube itself without being transferred to the surrounding tissue. Alternatively, the overtube may remain in an unlocked, flexible configuration so long as the overtube is maintained in the desired position. 
         [0027]    As shown in  FIG. 4 , an exemplary locking overtube  400  includes a distal end  402  which is inserted trans-orally through the esophagus into the stomach. The overtube  400  comprises a lumen  404  extending its entire length to an opening formed in the distal end  402 . A liner is passed through the lumen  404  and out of the opening in the distal end  404  to provide access to the stomach. The body  406  of the overtube  400  has a flexible configuration in which it is free to bend and change shape to simplify insertion through the GI tract. The shape locking mechanism may consist of a series of nested rings linked together via one or more cables and locked into position by tightening the cables. The overtube  400  includes a controller  410  actuated by the user to change the configuration of the body  406  between the locked and flexible configurations. In the locked configuration the overtube  400  withstands torsional and axial loads (e.g., those applied thereto as instruments are inserted through and withdrawn from the lumen) without changing shape. The locked overtube  400  provides a stable platform through which the gastric filling material may be inserted or removed, as the locked configuration maintains the distal end  402  in a substantially constant position within the stomach as forces are applied therethrough to remove the filler material. 
         [0028]    Alternatively, an overtube for use in conjunction with the invention may include all of the elements of the includes overtube  400  except for the shape locking mechanism and controller described to provide a passive, stable platform through which the gastric filling material may be inserted or removed. 
         [0029]    The present invention has been described with reference to specific exemplary embodiments. Those skilled in the art will understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts. Accordingly, various modifications and changes may be made to the embodiments. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.