Abstract:
A system of components may be used separately or in combination to create partial bypass of food, stomach and intestinal secretions and digestive enzymes. The systems are designed to be modular so as to allow the physicians to quickly replace certain elements to tailor the amount of material bypassed, the restriction applied to food passage, and the origin and destination of bypass according to the patient&#39;s individualized clinical needs.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/986,268, filed Jan. 7, 2011, which was a continuation-in-part of the following: U.S. patent application Ser. No. 12/752,697, filed Apr. 1, 2010, which claims the benefit of U.S. provisional patent application 61/211,853, filed Apr. 3, 2009; and U.S. patent application Ser. No. 12/833,605, filed Jul. 9, 2010, which claims the benefit of U.S. provisional patent application 61/270,588, filed Jul. 10, 2009, the disclosures of which are each hereby incorporated by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention generally relates to implants placed within gastrointestinal systems, including the esophagus, the stomach, and the intestines. In particular, it relates to implant systems having components implantable and removable using laparoscopic and endoscopic techniques for treatment of obesity, diabetes, reflux, and other gastrointestinal conditions. 
       BACKGROUND 
       [0003]    Bariatric surgery procedures, such as sleeve gastrectomy, the Rouen-Y gastric bypass (RYGB), and the biliopancreatic diversion (BPD), modify food intake and/or absorption within the gastrointestinal system to effect weight loss in obese patients. These procedures affect metabolic processes within the gastrointestinal system, by either short-circuiting certain natural pathways or creating different interaction between the consumed food, the digestive tract, its secretions and the neuro-hormonal system regulating food intake and metabolism. In recent years, there has been a growing clinical consensus that obese diabetic patients who undergo bariatric surgery see remarkable resolution of their Type-2 Diabetes Mellitus (T2DM) soon after the procedure. The remarkable resolution of diabetes after RYGB and BPD typically occurs too fast to be accounted for by weight loss alone, suggesting that there may be a direct impact on glucose homeostasis. The mechanism of this resolution of T2DM is not well understood, and it is quite likely that multiple mechanisms are involved. 
         [0004]    One of the drawbacks of bariatric surgical procedures is that they require fairly invasive surgery with potentially serious complications and long patient recovery periods. In recent years, there is an increasing amount of ongoing effort to develop minimally invasive procedures to mimic the effects of bariatric surgery using minimally invasive procedures. One such procedure involves the use of gastrointestinal implants that modify transport and absorption of food and organ secretions. For example, U.S. Pat. No. 7,476,256 describes an implant having a tubular sleeve with an anchor having barbs. While these implants may be delivered endoscopically, the implants offer the physician limited flexibility and are not readily removable or replaceable, as the entire implant is subject to tissue in-growth after implantation. Moreover, stents with active fixation means, such as barbs that penetrate into the surrounding tissue, may potentially cause tissue necrosis and erosion of the implants through the tissue, which can lead to serious complications such as systemic infection. Also, due to the intermittent peristaltic motion within the digestive tract, implants such as stents have a tendency to migrate. 
       SUMMARY 
       [0005]    According to various embodiments, the present invention is a partial gastrointestinal implant system for treating metabolic disorders, such as diabetes and obesity. According to some embodiments, the system includes an anchoring element (e.g., stents, rings, fabric, or elastomeric cuffs) with sleeve or graft extensions, anchored within the gastrointestinal system (e.g., the esophagus, the gastro-esophageal junction, the pyloric junction, the duodenum, the jejunum, and/or the ileum), the anchoring element including docking capability, and tubular implants (e.g., thin sleeves or stent grafts) configured to be reversibly attached to the anchoring element. According to some embodiments, the system allows attachment of one or multiple tubular implants to the gastrointestinal anchoring element. According to some embodiments, the cross-section area of the implants can be varied or adjusted, such that systems can be created where food or secretions entering the proximal portion of the system can be selectively channeled to alternate destinations, thereby creating customized and partial bypass systems. By adjusting the sizing of the sleeves and the restrictive elements in the system, this procedure can also simulate mechanisms of restrictive surgical procedures. 
         [0006]    According to various embodiments, the present invention is a modular intra-luminal implant system for treating metabolic disorders such as obesity and diabetes, which provides far more flexible therapy alternatives than single devices to treat these disorders. These implant systems include components that can be selectively added or removed to mimic a variety of bariatric surgical procedures with a single basic construct. The fundamental building blocks of the system include anchoring implants that are placed within the GI system or some instances around particular organs. These low-profile implants are designed for long-term performance with minimal interference with normal physiological processes. Features of these anchoring implants allow them to act as docking stations for therapy implants designed for achieving certain metabolic modification goals. By using a combination of anchoring implants with corresponding replaceable tubular elements that dock with them, it is possible to design therapies with particular metabolic modification goals or those that mimic currently practiced bariatric surgical procedures. This allows the physician to customize the therapy to the patient at the time of the initial procedure but also allows the flexibility to alter the therapy during the lifetime of the patient by replacing individual components. 
         [0007]    According to some embodiments, the modular systems of the invention includes an anchoring implant portion (docking element) including an expandable structure (e.g., a low profile stent or ring or fabric/elastomeric cuff) anchored within the esophagus, the gastro-esophageal junction, the pyloric junction, the duodenum or the jejunum and may have sleeve or graft extensions. The stents may be balloon expandable or self-expanding and anchor against the tissue with radial force. The rings could be made of self-expanding nitinol and anchor to the tissue by entrapment of the tissue within the ring elements or by radial force. The cuffs could be either sutured or stapled or permanently or reversibly attached by other mechanical means to the tissue. The anchoring implant includes or is adapted to receive (e.g., endoscopically) features that enable docking functionality. The docking functionality of the stent, ring or cuff, for example, could take the form of magnetic elements, hooks, mating mechanical elements or structures (e.g., the stent braid or mesh or corresponding hook and loop structures) that are integral to the framework of the stent, ring or cuff or the sleeve or graft extension. The system also could be such that the docking functionality is not integral to the stent, ring or cuff but is introduced later by attaching other elements such as magnets, hooks, mating mechanical elements, etc. to the framework of the stent, ring, cuff or to the sleeve/graft extension of the above implants. Therapeutic implants, such as tubular sleeves or stent grafts, are adapted to be reversibly attached to the anchoring implants. These therapeutic implants will have corresponding features (e.g., magnets, hooks, mechanical elements) to enable docking to the anchoring implants, so that the therapeutic implants can be reversibly attached to the anchoring implants. In some embodiments, the tubular implants will not be in contact with tissue to minimize or prevent tissue in-growth and facilitate easy removal with endoscopic instrumentation after long-term implantation. 
         [0008]    The present invention, according to various embodiments, includes a modular gastrointestinal implant system for treating metabolic disorders such as diabetes and obesity by creating partial internal bypasses of food and organ secretions within the gastro-intestinal tract. The system includes low-profile anchoring implants that are affixed within the stomach, the esophagus, the intestine (or at internal junctions of these organs) or around these organs and enable secure attachment of (i.e., act as docking elements for) other implants; and other implants whose design facilitates partial internal by-pass of food and organ secretions from one site within the gastro-intestinal tract to other sites within the gastro-intestinal tract (partial bypass elements) that are attached to these anchoring implants. In some embodiments, the low-profile implant is a stent-graft or a stent with a sleeve element. In some embodiments, the low-profile implant is a fabric or elastomeric cuff. In some embodiments, the low-profile implants are stents divided into multiple channels. In some embodiments, the low-profile implants are multi-limb stent-grafts. 
         [0009]    According to various embodiments, the present invention is a method for treating metabolic disorders such as diabetes and obesity consisting of (a) placing low-profile implants that can be affixed within the stomach, the esophagus, the intestine or at internal junctions of these organs or around these organs and (b) securely attaching other gastro-intestinal implants that permit partial internal by-pass of food and organ secretions from one site within the gastro-intestinal tract to other sites within the gastro-intestinal tract, to these low-profile implants. 
         [0010]    According to various embodiments, the present invention is a method for creating a reversible treatment for metabolic disorders such as diabetes and obesity consisting of (a) placing low-profile implants that can be affixed within the stomach, the esophagus, the intestine or at internal junctions of these organs or around these organs and (b) placing other gastro-intestinal implants that permit partial internal by-pass of food and organ secretions from one site within the gastro-intestinal tract to other sites within the gastro-intestinal tract, to these low-profile implants and not to the tissue so that the procedure can be reversed easily. 
         [0011]    According to various embodiments, the present invention is a modular system for selectively restricting passage of food and organ secretions within the gastro-intestinal tract that consists of (a) low-profile implants that are affixed within the stomach, the esophagus, the intestine or at internal junctions of these organs or around these organs and which enable secure attachment of other implants (docking elements) and (b) other gastro-intestinal implants whose design facilitates selective restriction of passage of food and organ secretions from one site within the gastro-intestinal tract to other sites within the gastro-intestinal tract that are attached to these permanent implants (restrictive bypass elements). In some embodiments, the structure or design feature of the implant that enables secure attachment of one or more implants to it consists of a double-braid with hollow space between the two braids. 
         [0012]    According to various embodiments, the present invention is a method for treating metabolic disorders such as diabetes and consisting of (a) placing low-profile implants that can be affixed within the stomach, the esophagus, the intestine or at internal junctions of these organs or around these organs and (b) securely attaching other gastro-intestinal implants that selectively restrict passage of food and organ secretions from one site within the gastro-intestinal tract to other sites within the gastro-intestinal tract, to these low-profile implants. 
         [0013]    According to various embodiments, the present invention is a method for creating a reversible treatment for metabolic disorders such as diabetes and obesity and gastro-esophageal reflux disease (GERD) consisting of (a) placing low-profile implants that can be affixed within the stomach, the esophagus, the intestine or at internal junctions of these organs or around these organs and (b) placing other gastro-intestinal implants that selectively restrict passage of food and organ secretions from one site within the gastro-intestinal tract to other sites within the gastro-intestinal tract, to these low-profile implants and not to the tissue so that the procedure can be reversed easily. 
         [0014]    According to various embodiments, the present invention is a modular gastrointestinal implant system for treating metabolic disorders such as diabetes and obesity by creating partial internal bypasses of food and organ secretions within the gastro-intestinal tract. The system includes an anchoring element configured for engaging an esophagus, the anchoring element having a docking feature; a first gastrointestinal implant having a coupling feature for engaging and coupling with the docking feature of the anchoring element and sized and shaped to extend from the esophagus to the duodenal bulb; wherein the docking feature and coupling feature are configured such that the first implant may releasably couple with the anchoring element to facilitate removal of the tubular implant; and a second gastrointestinal implant adapted to extend from the stomach or the duodenal bulb into the duodenum; wherein the first and second implants are adapted to partially overlap within the duodenal bulb. 
         [0015]    According to some embodiments, the present invention is a modular gastrointestinal implant system for treating metabolic disorders such as diabetes and obesity by creating partial internal bypasses of food and organ secretions within the gastro-intestinal tract. The system includes a first anchoring element configured for engaging an esophagus, the first anchoring element having a docking feature; a second anchoring element configured for engaging a duodenum; a first gastrointestinal implant having a proximal end including a coupling feature for engaging the docking feature of the first anchoring element and a distal end adapted to couple with the second anchoring element; wherein the docking feature and coupling feature are configured such that the first implant may releasably couple with the anchoring element to facilitate removal of the tubular implant; and a second gastrointestinal implant adapted to extend from the stomach or the duodenal bulb into the duodenum, the second implant adapted to couple with the second anchoring element; wherein the first and second implants are adapted to partially overlap within the second anchoring element. 
         [0016]    According to various embodiments, the present invention is a method of treating metabolic conditions such as diabetes and obesity, which method includes securing a first anchoring element to the esophagus, the first anchoring element having a docking feature; securing a second anchoring element to the duodenum; implanting a first gastrointestinal implant having a proximal end including a coupling feature for engaging the docking feature of the first anchoring element and a distal portion adapted to couple with the second anchoring element; releasably coupling the coupling feature of the first gastrointestinal implant with the docking feature of the first anchoring element and coupling the distal portion with the second anchoring element; implanting a second gastrointestinal implant adapted to extend from the stomach or the duodenal bulb into the duodenum, the second implant adapted to couple with the second anchoring element; coupling the second implant to the second anchoring element, such that the first and second implants partially overlap within the second anchoring element. 
         [0017]    According to various embodiments, the present invention is a gastrointestinal implant system for treating metabolic disorders such as diabetes and obesity by creating partial internal bypasses of food and organ secretions within the gastro-intestinal tract, which system includes a first gastrointestinal implant having a feature for engaging and coupling with the docking feature of the anchoring element and sized and shaped to extend from the esophagus to the duodenal bulb; and a second gastrointestinal implant adapted to extend from the stomach or the duodenal bulb into the duodenum; wherein the first and second implants are adapted to partially overlap within the duodenal bulb. 
         [0018]    Furthermore, other documents that contemplate gastric and intestinal bypass using sleeve elements (e.g., WO/2007/136468) have a significant drawback. The sleeve element between the esophagus and the intestine passing through the stomach has no propulsion means to push food forward. Hence, if all the food from the esophagus (which is at this stage in semi-solid form) were to enter this section of the sleeve, it is possible there will be a backup of food causing dysphagia-like symptoms in the patient. Embodiments of the present invention describe partial bypass elements where only part of the food bypasses the stomach, such that if there is resistance to the passage of the food through the sleeve element, the food has an alternative pathway to move forward hence eliminating the chances of dysphagia. 
         [0019]    While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIGS. 1-4  are sectional views of a portion of the digestive tract in the body showing partial bypass systems having an external band implanted around the outside diameter of the esophagus and a first tubular implant (sleeve) implanted inside the esophagus and anchored to the external band. A first tubular implant extends through the stomach into the duodenal bulb and a second implant (sleeve) is implanted in the stomach antrum and extends into and/or through the duodenum. 
           [0021]      FIG. 5  shows an exemplary endoscope used for diagnostic and therapeutic procedures in the gastro intestinal (GI) tract. 
           [0022]      FIG. 6  is a sectional view of a portion of the digestive tract in the body, with an endoscope passing through the esophagus into the stomach, and the end of the scope positioned to allow viewing of the pylorus. 
           [0023]      FIG. 7  is a schematic view showing a trocar and cannula operable to access the implant location of the duodenal bulb using laparoscopic techniques. 
           [0024]      FIG. 8  is a sectional view of a portion of the digestive tract in the body. An implant is implanted in the duodenal bulb. The implant has two interior lumens as in section A-A or the alternative section A-A that allow two tubular implants to be sleeved adjacent to each other (i.e., overlapping). 
           [0025]      FIG. 9  is a sectional view of a portion of the digestive tract in the body. A first implant is implanted in the duodenal bulb and a second implant is implanted in the esophagus. The implants have two interior lumens as in section A-A or the alternative section A-A that allow two tubular implants to be sleeved adjacent to each other (i.e., overlapping). 
           [0026]      FIGS. 10 and 11  are sectional views of a portion of the digestive tract in the body. An external anchor is positioned around the outside diameter of the esophagus and a bifurcation implant is implanted into the duodenal bulb. A first tubular implant (sleeve) is implanted in the esophagus and is anchored to the external anchor at a proximal portion and to the implant at a distal portion. A second sleeve is implanted in the stomach antrum extending into and/or through the duodenum. 
           [0027]      FIGS. 12 and 13  are sectional views of a portion of the digestive tract in the body. An external anchor is positioned around the outside of the esophagus and a first tubular implant (sleeve) is implanted in the esophagus and anchored to the external anchor. The first tubular implant extends through the duodenum to the ligament of Treitz. A second sleeve is anchored to the external anchor and extends into and/or through the stomach. 
           [0028]      FIGS. 14-16  are sectional views of a portion of the digestive tract in the body. An external anchor is implanted around the outside of the esophagus and a first tubular implant (sleeve) is implanted in the esophagus and anchored to the external anchor. The first tubular implant extends into the duodenum to duodenal bulb. A second sleeve is implanted from the esophagus into the stomach. A third sleeve is implanted from the pylorus or stomach antrum into or through the duodenum. 
           [0029]      FIGS. 17-18  are sectional views of a portion of the digestive tract in the body. An external anchor is positioned around the outside of the esophagus. A first tubular implant (sleeve) is implanted inside the esophagus and anchored to the external anchor and extends from the esophagus into the duodenum to the duodenal bulb. The first tubular implant has a valve (section C-C) opening that (like stoma) allows some portion of the food entering the esophagus to enter the upper portion of the stomach. A second sleeve is implanted from the stomach antrum into or through the duodenum. 
           [0030]      FIG. 19  is a sectional view of a portion of the digestive tract in the body. An external anchor is positioned around the outside of the esophagus. A bifurcated tubular implant (sleeve) is implanted on the inside of the esophagus and is anchored to the external anchor. A first branch of the bifurcated implant extends to an implant positioned in the duodenal bulb and a second branch extends into the stomach. A second tubular implant extends from the bifurcated tubular implant into the duodenum. 
           [0031]      FIG. 20  is a schematic view of a delivery device for implanting an internal implant. 
       
    
    
       [0032]    While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION 
       [0033]      FIGS. 1 and 2  are sectional views of a portion of the digestive tract in a human body. As a person ingests food, the food enters the mouth  100 , is chewed, and then proceeds down the esophagus  101  to the lower esophageal sphincter at the gastro-esophageal junction  102  and into the stomach  103 . The food mixes with enzymes in the mouth  100  and in the stomach  103 . The stomach  103  converts the food to a semi-fluid substance called chyme. The chyme enters the pyloric antrum  104  and exits the stomach  103  through the pylorus  106  and pyloric orifice  105 . The small intestine is about 21 feet long in adults and is comprised of three sections: the duodenum  112 , the jejunum  113 , and the ileum (not shown). The duodenum  112  is the first portion of the small intestine and is typically 10-12 inches long. The duodenum  112  is comprised of four sections: the superior, descending, horizontal and ascending sections. The duodenum  112  ends at the ligament of Treitz  109 . The papilla of Vater  108  is the duct that delivers bile and pancreatic enzymes to the duodenum  112 . The duodenal bulb  107  is the portion of the duodenum which is closest to the stomach  103 . 
         [0034]    As shown, an external anchoring element or band  110  is secured or positioned around the outside of the esophagus and a first gastrointestinal or tubular implant  111  (e.g., sleeve) is implanted inside of the esophagus and anchored magnetically through the esophageal tissue to the external band  110 . As shown in  FIG. 1 , magnets  135  on the anchoring element  110  and magnets  136  on the tubular implant  111  magnetically interact with (e.g., attraction, repulsion, or levitation) each other to anchor or secure the tubular implant  111  to the external band  110  in a removable or reversible configuration. The magnets  135  on the external anchoring element or band  110 , which can be located on the inside surface, outside surface, or embedded in the middle of the band, serve as a coupling or docking feature. The magnets  136  on the tubular implant  111 , which magnetically interact with the magnets  135  on the anchoring element, serve as a coupling feature for the implant  111 . Suitable exemplary materials for the magnets include neodymium-iron-boron [Nd—Fe—B], samarium-cobalt [Sm—Co], alnico, and hard ferrite [ceramic]. The magnets may be plated with gold or platinum or other material to make them radio-opaque or to improve the corrosion resistance. The magnets may be encapsulated within a metal casing such as titanium or stainless steel to improve the corrosion resistance and the biocompatibility. According to various embodiments, the external band  110  is made from one or more elastomers (e.g., silicon, polyurethane, and ePTFE), metals, or fabrics (e.g., Dacron or a combination of polymers and textile materials). 
         [0035]    As shown, the gastrointestinal implant  111  extends into the duodenum  112  to the duodenal bulb  107 . According to some embodiments, the sleeve  111  or the anchor mechanism  110  may form a restrictive stoma  262  in the esophagus (see  FIGS. 1 and 2 ), for example, by reducing or restricting the internal diameter of the esophagus. According to other embodiments, as shown for example in  FIGS. 3 and 4 , a stoma is not formed. A second sleeve  300  or  301  is implanted from the stomach antrum  104  (or from the duodenal bulb  107 ) to the mid-portion of the duodenum (see, e.g.  FIG. 1 ) or to the ligament of Treitz (see, e.g.,  FIG. 2 ). According to some embodiments, the two sleeves each form a D-shaped transverse section in the overlap section (e.g., the region in or near the duodenal bulb  107 ), such that when combined they together form a generally circular overall transverse cross-section (see, e.g., section A-A in  FIGS. 1 and 2 ). The first sleeve  111  (extending between the esophagus  102  and the duodenal bulb  107 ) serves to bypass the stomach  103 . The second sleeve  300  (or sleeve  301 ) allows the stomach secretions to bypass a portion (or all) of the duodenum  112 . According to some embodiments, at least one of the first sleeve  111  and the second sleeve  300  are formed or shaped such that the portion of the sleeve located in the duodenal bulb has and generally holds the D-shape cross section (as shown in section A-A). In other embodiments, these portions of the first sleeve and/or second sleeve  300  are not preformed or shaped, but instead are made from a material having sufficient compliance to conform to the duodenal bulb, in such a way as to have a substantially D-shape cross section. 
         [0036]    According to other embodiments, the anchoring mechanism  110  may be formed from other structures. Exemplary structures (shown in  FIG. 1 ) include a stent  500  and/or interlocking mechanical rings  501 . The stent  500  can be a self expanding type or a balloon expandable type. As shown, the rings  501  are configured such that an outer ring  141  positioned around an outer surface of the esophagus is sized and shaped to interlock with an inner ring  143   a  or  143   b  positioned around an inner surface of the esophagus. According to some embodiments, the anchoring mechanism  110  is integrally formed with the sleeve  111 , and, in other embodiments, the anchoring mechanism is structurally separate from and adapted for coupling with the sleeve  111 . According to other embodiments, any of the internal anchoring structures disclosed in co-pending, commonly assigned U.S. patent application Ser. No. 12/752,697 (incorporated herein by reference) may be used as the anchoring mechanism  110 . According to still other embodiments, any of the external anchoring structures disclosed in co-pending, commonly assigned U.S. patent application Ser. No. 12/833,605 (incorporated herein by reference) may be used as the anchoring mechanism  110 . Likewise, the implants or sleeves  111  and  300  may be formed in any configuration or from any material disclosed in either of U.S. patent application Ser. No. 12/752,697 or U.S. patent application Ser. No. 12/833,605. Likewise the implants or sleeves may be couples or anchored to the anchoring mechanism using any arrangement disclosed in either of U.S. patent application Ser. No. 12/752,697 or U.S. patent application Ser. No. 12/833,605. 
         [0037]      FIG. 3  is an alternative embodiment of  FIG. 1  where the tubular implant does not cause or form a stoma in the esophagus.  FIG. 4  is an alternative embodiment of  FIG. 2  where the tubular implant does not cause or form a stoma in the esophagus. 
         [0038]      FIG. 5  shows an endoscope  114 . Endoscopes  114  are used for diagnostic and therapeutic procedures in the gastrointestinal (GI) tract. The typical endoscope  114  is steerable by turning two rotary dials  115  to cause deflection of the working end  116  of the endoscope. The working end (or distal end) of the endoscope  116  typically contains two fiber bundles for lighting  117 , a fiber bundle for imaging  118  (viewing) and a working channel  119 . The working channel  119  can also be accessed on the proximal end of the endoscope. The light fiber bundles and the image fiber bundles are plugged into a console at the plug in connector  120 . The typical endoscope has a working channel in the 2.6 mm to 3.2 mm diameter range. The outside diameters of the endoscopes are typically in the 8 mm to 12 mm diameter range, depending on whether the endoscope is for diagnostic or therapeutic purposes. 
         [0039]      FIG. 6  shows a sectional view of a portion of the digestive tract in a human body. As shown in  FIG. 6 , an endoscope  114  has been inserted through: the mouth  100 , esophagus  101 , stomach  103  and pyloric antrum to allow visualization of the pylorus  106 . 
         [0040]      FIG. 7  shows a sectional view of a portion of the digestive tract in the body with a trocar  260  and cannula  261  inserted to access the implant location of the duodenal bulb, gastroesophageal junction, or other suitable location using laparoscopic techniques. An alternative access route is to use natural orifice surgery (e.g., access via the esophagus, stomach, belly button or vagina). 
         [0041]      FIG. 8  shows a sectional view of a portion of the digestive tract in the body. As shown, a bifurcated anchor or implant  302  is implanted in the duodenal bulb  107  or pylorus  106 . The implant has two interior lumens or anchoring structures  307 ,  309 , as shown in section A-A or the alternative section A-A, that may couple with or otherwise allow two tubular implants to be sleeved adjacent to each other (i.e., overlapping). According to other embodiments, the implant  302  is structured to have D-shaped transverse sections, as shown above for example in section A-A in  FIGS. 1 and 2 . According to various embodiments, the implant  302  is configured to couple or anchor to the duodenal bulb  107  (or pylorus  106 ) and serves as an anchoring location for an end of the tubular implants or sleeves. According to various embodiments, the anchoring mechanism  110  includes structures to urge or otherwise cause the overlapping portions of the first sleeve  111  and the second sleeve  300  to form a specified shape, such as the D-shape described above and shown, for example, in section A-A of  FIG. 1 . 
         [0042]    In the embodiments such as that shown in section A-A, the implant  302  further includes an area  311  which is located inside the implant  302  and outside the lumens  307 ,  309 . The anchor or implant  302 , according to various embodiments, includes a transition or seal feature covering the area  311  (shown for example in  FIG. 8  below section A-A). This transition of seal feature may be shaped and configured to block or cover the area  311  (either partially or entirely), such that materials exiting the stomach cannot substantially bypass the sleeves coupled to either of the lumens  307 ,  309 . In various embodiments, this seal feature may be a sleeve, film or other structure made from, for example, a urethane or Goretex material. In some embodiments, the area  311  is covered with a structure made from one or more elastomers (e.g., silicon, polyurethane, and ePTFE), metals, or fabrics (e.g., Dacron or a combination of polymers and textile materials). 
         [0043]      FIG. 9  shows a sectional view of a portion of the digestive tract in the body. As shown, a bifurcated implant  302  is implanted into the duodenal bulb  107  (or pylorus  106 ). A second bifurcation implant  303  is implanted in the esophagus  102 . According to various embodiments, the second implant  303  is formed of any of the configurations described above with respect to the bifurcated implant  302 . 
         [0044]      FIG. 10  is a sectional view of a portion of the digestive tract in a human body. As shown, a tubular implant  111  (sleeve) is implanted inside the esophagus (e.g., on the inside surface) and anchored mechanically or magnetically (as further described above) through the esophageal tissue to the external band  110  which is secured around the outside of the esophagus. As shown, the tubular implant  111  extends into the duodenum  112  to the duodenal bulb  107 . The sleeve in the esophagus may form a restrictive stoma  262  in the esophagus. A second sleeve  300  is implanted from the stomach antrum  104  to the mid-portion of the duodenum. 
         [0045]    As further shown in  FIGS. 10 and 11 , the two sleeves are inserted into a bifurcated implant  302  to anchor the sleeves and form the transition shape. According to some embodiments, the two sleeves each form a circular shape individually in the overlapping section. The two round sections of the implant form a combined round outer diameter (see, e.g., section A-A in  FIG. 10 ). According to other embodiments, the overlapping ends of the sleeves  111 ,  300  (i.e., the distal end of the sleeve  111  and the proximal end of the sleeve  300 ) are formed with (or are otherwise capable of conforming to) a D-shaped section, such that collectively the ends form a generally circular transverse section shape. The sleeve between the esophagus  102  and the duodenal bulb  107  bypasses the stomach  103 . The second sleeve is located from the distal stomach antrum  104  (or pylorus) to the mid-duodenum (see  FIG. 10 ) or to the ligament of Treitz (see  FIG. 11 ). The second sleeve  300  allows stomach secretions to bypass a portion of the duodenum  112 . 
         [0046]      FIGS. 12 and 13  show sectional views of a portion of the digestive tract in the body. As shown, an external band  110  is implanted around the outside of the esophagus. According to other embodiments, a bifurcated implant is implanted inside the esophagus. A tubular implant  111  (sleeve) is implanted on the inside surface of the esophagus and anchored magnetically or mechanically through the esophageal tissue to the external band  110 . The tubular implant  111  extends into the duodenum (e.g., to the ligament of Treitz). As shown, the anchor or band around the esophagus forms a restrictive stoma  262  in the esophagus. A second sleeve  303  is implanted from the esophagus (again, anchored to the external band  110  or bifurcated implant) and extends into the upper portion of the stomach near the fundus  304  (see  FIG. 12 ) or the lower portion of the stomach near the antrum  104  (see  FIG. 13 ). 
         [0047]    The two sleeves can each form a circular shape individually (see, e.g., section B-B and alternative section B-B) in the overlap section in the esophagus or alternatively the overlap portions of the sleeves can have or otherwise form D-shaped sections. The tubular element or sleeve  111  of the bypass system delivers food and secretions past the upper duodenum where as the rest of the food is allowed to flow into the upper duodenum where it will mix with the biliopancreatic secretions thus creating a partial duodenal bypass where controlled gastric emptying is still functional. Because of some level of biliopancreatic interaction with the food, this type of procedure is likely to result in the patient experiencing less complications such protein deficiency 
         [0048]      FIGS. 14-16  show sectional views of a portion of the digestive tract in the body. As shown, an external anchor or band  110  is implanted around the outside diameter of the esophagus (or alternatively a bifurcated implant is implanted inside). A tubular implant  111  (sleeve) is implanted on the inside surface of the esophagus and anchored magnetically or mechanically through the esophageal tissue to the external band  110 . The tubular implant  111  extends from the esophagus into the duodenal bulb where a distal portion of the implant  111  couples to bifurcated implant  302 . 
         [0049]    As shown, the anchor or band around the esophagus forms a restrictive stoma  262  in the esophagus. A second sleeve  303  is implanted from the esophagus (again, anchored to the external band  110  or bifurcated implant) and extends into the upper portion of the stomach near the fundus  304  (see  FIG. 14 ) or the lower portion of the stomach near the antrum  104  (see  FIGS. 15 and 16 ). As further described above, the two sleeves can each form a circular sectional shape (see section B-B in  FIG. 14 ) in the overlap section in the esophagus or alternatively have or otherwise form D-shaped sections. A third sleeve  306  is implanted from the pylorus or stomach antrum and extends into the mid-duodenum (see, e.g.,  FIGS. 14 and 15 ) or to the ligament of Treitz (see, e.g.,  FIG. 16 ). The two sleeves overlapping in or near the duodenum (e.g., sleeve  111  and sleeve  306 ) can each form a circular shape (or alternatively D-shaped sections) as shown. 
         [0050]    According to various embodiments, the gastrointestinal system includes two stents, a first stent in the esophagus and a second stent at the pyloric junction. The first stent couples to and secures a proximal portion of the implant  111  and a proximal portion of the second sleeve  303 . The second stent couples to and secures a distal portion of the implant  111  and a proximal portion of the third sleeve  306 . 
         [0051]    As shown, the sleeve  111  includes a tubular element that bypasses a majority of the food ingested past the stomach emptying it in to the small intestine. The remainder of the food empties in to the stomach where it gets mixed with stomach enzymes and peptides such as Ghrelin released by the fundus of the stomach. The sleeve  306  at the pyloric junction redirects this mixture past the small intestine by means of the tubular element attached to it. Thus this system can mimic both the restrictive and malabsorptive features of a stomach reduction procedure as well as reduction of exposure of peptides such as Ghrelin to the upper duodenum. 
         [0052]    An external anchor is positioned around the outside of the esophagus. A first tubular implant (sleeve) is implanted inside the esophagus and anchored to the external anchor and extends from the esophagus into the duodenum to the duodenal bulb. The first tubular implant has a valve (section C-C) opening that (like stoma) allows some portion of the food entering the esophagus to enter the upper portion of the stomach. A second sleeve is implanted from the stomach antrum into or through the duodenum. 
         [0053]      FIGS. 17 and 18  show sectional views of a portion of the digestive tract in the body. As shown, an external anchor or band is implanted around the outside of the esophagus. According to alternative embodiments, a bifurcated implant is implanted inside. A tubular implant  111  (sleeve) is implanted on the inside surface of the esophagus and anchored magnetically or mechanically through the esophageal tissue to the external band  110 . The tubular implant  111  extends into the duodenum to the duodenal bulb. The band around the esophagus forms a restrictive stoma  262  in the esophagus. A valve  307  is constructed into the wall of the sleeve  111 . The valve acts as a stoma that can allow a portion of the food entering the sleeve  111  to exit the stoma opening into stomach. According to various embodiments, the valve  307  is any of an opening, a hole, a slit, or a mechanical valve mechanism. Exemplary structures for the valve  307  are shown in section C-C and alternative sections C-C in  FIGS. 17 and 18 . A second sleeve  306  is implanted from the pylorus or stomach antrum to the midpoint of the duodenum. As further described above, the two sleeves can each form a circular shape individually in the overlap section in the esophagus or alternatively “D” shaped sections (see, e.g., section A-A in  FIGS. 17 and 18 ). 
         [0054]      FIG. 19  shows a sectional view of a portion of the digestive tract in the body. As shown, an external band is implanted around the outside diameter of the esophagus (or alternatively a bifurcated implant is implanted inside). A bifurcated tubular implant  310  (sleeve) is implanted on the inside surface of the esophagus and anchored magnetically (or mechanically) through the esophageal tissue to the external band. A second tubular implant  311  extends from the bifurcated tubular implant  310  into the duodenum  112  to duodenal bulb  107 . The band around the esophagus may form an optional restrictive stoma in the esophagus. A third sleeve  312  is implanted from the bifurcated tubular implant in the esophagus to the lower portion of the stomach near the stomach antrum or pylorus. A fourth sleeve  306  is implanted from the pylorus or stomach antrum to the middle or the end of the duodenum near the ligament of Treitz. As further described above, the two sleeves can each form a circular shape (or alternatively D shaped sections individually) in the overlap sections in the esophagus (or the duodenal bulb section). In some embodiments, the tubular implant  310  is formed in a branched (e.g., Y-shaped) configuration, having a proximal end adapted for coupling or anchoring in the esophagus and a distal portion including branches or limbs (e.g., sleeve  311  and sleeve  312 ). In other embodiments, the tubular implant  310  includes more than two branches (or limbs). 
         [0055]    Various embodiments of the present invention shown and described above partial bypass elements where only part of the food bypasses the stomach (e.g.,  FIGS. 12-19 ). In these embodiments, there is an alternative flow path for food exiting the esophagus, such that if there is resistance to the passage of the food through the bypass sleeve element, the food has an alternative pathway to move forward. Such a configuration may help to reduce or eliminate dysphagia or dysphagia-like symptoms in a patient. 
         [0056]      FIG. 20  shows a delivery catheter with an implant  110  loaded on to it for delivering a self-expanding internal tubular implant or stent. The catheter may be of an over-the-wire construction or a rapid exchange version. The delivery catheter is constructed with a smaller outside diameter to allow the catheter to be inserted through the working channel of the endoscope  114 . The delivery catheter consists of an outer catheter  151  and an inner catheter  152 . Attached to the inner catheter is a stent retainer  159 . The purpose of the stent retainer  159  is to prevent the stent from releasing from the delivery catheter prematurely during deployment. The stent retainer is fastened to the inner catheter. The stent retainer  159  can be made from metal or plastic and can be made radio-opaque by making from it from a radio-opaque material such as tantalum. The stent retainer has a complementary shape that holds the tips on the stent and does not allow the stent to move distally or forward until the outer sheath  151  is fully retracted to the stent retainer  159 . The catheter has a side port  156  which allows the space between the inner and outer sheaths to be flushed with saline. The outer sheath  151  and inner sheath  152  may be made from made from a simple single layer polymer extrusion such as from polyethylene or PTFE. 
         [0057]    The outer sheath may also be constructed as follows. The sheath inner diameter surface is constructed of a thin wall PTFE liner  157 . A layer of reinforcement  158  is placed over the PTFE liner. The reinforcement may be either a braid of wire or a coil of wire. The wire cross section can be either round or rectangular. The preferred material for the wire is a metal such as 316 or 304 stainless steel or Nitinol or other suitable material. The wire diameters are typically in the 0.0005 inch to 0.010 inch diameter range. The outer jacket material is preferably reflowed into the reinforcement layer by melting the material and flowing it into the spaces in between the braided wire or the coil wires. The outside diameter of this catheter will range typically from 1 mm to 4 mm. The catheter can be constructed to be an over the wire catheter or a rapid exchange catheter. For a rapid exchange design, the guide wire will enter the central lumen of the distal end of the catheter and exit at point  188 . For an over-the-wire design, the guide wire will enter the central lumen of the distal end of the catheter and exit at point  189 . 
         [0058]    Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.