Systems and methods for treating obesity and type 2 diabetes

The present invention provides systems and methods for treating and/or controlling obesity and type II diabetes. In one aspect of the invention, a device for treating obesity includes a flow restrictor and an anchor coupled to the flow restrictor. The flow restrictor is movable between a first or collapsed configuration sized and shaped for endoscopic advancement through the patient's esophagus and into a distal region of the stomach and a second or operative configuration sized and shaped for inhibiting a flow of chyme from the stomach to the pyloric sphincter. It is believed that this will cause the prolongation of satiety, and result in fewer meals being eaten and/or smaller meals being ingested. The anchor is movable between a first or collapsed configuration sized and shaped for advancement through the esophagus, stomach and pyloric sphincter and into the proximal region of the duodenum and a second or operative configuration sized and shaped to inhibit proximal movement of the anchor through the pyloric sphincter.

BACKGROUND OF THE INVENTION

The present invention relates to the field of obesity and diabetes and more specifically to minimally invasive systems and methods for controlling or treating obesity and/or type 2 diabetes.

Obesity is one of the leading preventable causes of death worldwide and has become a global epidemic affecting more than 400 million people. In the United States alone, approximately 300,000 obesity-linked deaths occur annually, and obesity-related co-morbidities lead to nearly $150 billion in healthcare spending. Obesity is a medical condition associated with many subsequent diseases, including type-II diabetes, cardiovascular disease, sleep apnea and certain types of cancer. These conditions often have severe adverse effects on overall health, reduce quality of life, limit productivity, lead to significant medical costs, and can ultimately lead to reduced life expectancy.

While obesity has a range of contributing causes, the vast majority of obese individuals are obese because they overeat, fail to exercise adequately, and in some cases have genetic predispositions to weight gain. The primary treatment for obesity is dieting, routine physical exercise, and in some cases pharmacologic therapy. Obesity surgery, including irreversible Roux-en-Y gastric bypass (RYGB) and Laparoscopic Adjustable Gastric Banding (LAGB), involves surgical restriction of the stomach. These interventions are typically directed at either (i) reducing the caloric intake of the patient by triggering the satiety impulse more rapidly or physically removing the ability of the individual to ingest more than a limited amount of food, or (ii) inhibiting the ability of the individual's digestive system to extract the full caloric value of the food being eaten.

The current surgical treatments for obesity, although often effective in achieving sustainable weight loss and thus reducing associated co-morbidities, involve gross anatomical reconstruction of the digestive system, which may be irreversible. Unfortunately, as has become widely publicized in the print and broadcast media, there can be significant adverse events, complications, and/or mortality associated with the most radical of these procedures (including but not limited to RYGB). In a large number of patients, subsequent surgical procedure(s) are required to address the complication(s) from the original surgery. While use of RYGB and LAGB are approved for individuals with lower BMIs (i.e., <40), the risks associated with the procedures have limited their adoption and/or use to only the morbidly obese population (>40 BMI). Recent reports indicate that there is a need to expand the options for obesity surgery in order to provide safer alternatives for individuals who are not prepared to risk the adverse consequences of radical RYGB and LAGB surgery, but for whom a surgical intervention is wholly appropriate. In fact, many individuals who could benefit from surgical intervention before their excess weight results in serious health problems forego surgery due to the significant complications and high rates of long-term adverse events leading to poor quality of life. Thus, there is a growing need for an effective and safe alternative to obesity surgery for the obese patient population worldwide.

Diabetes mellitus type 2 or type 2 diabetes is a disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. There are an estimated 23.6 million people in the U.S. (7.8% of the population) with diabetes with 17.9 million being diagnosed, 90% of whom are type 2. With prevalence rates doubling between 1990 and 2005, CDC has characterized the increase as an epidemic. Traditionally considered a disease of adults, type 2 diabetes is increasingly diagnosed in children in parallel to rising obesity rates due to alterations in dietary patterns as well as in life styles during childhood.

Type 2 diabetes is a chronic, progressive disease that has no established cure, but does have well-established treatments which can delay or mitigate the inevitable consequences of the condition. Often, the disease is viewed as progressive since poor management of blood sugar leads to a myriad of steadily worsening complications. However, if blood sugar is properly maintained, then the disease is effectively cured—that is, patients are at no heightened risk for neuropathy, blindness, or any other high blood sugar complication. Type 2 is initially treated by adjustments in diet and exercise, and by weight loss, most especially in obese patients. The amount of weight loss which improves the clinical picture is sometimes modest (2-5 kg or 4.4-11 lb); this is almost certainly due to currently poorly understood aspects of fat tissue activity, for instance chemical signaling (especially in visceral fat tissue in and around abdominal organs).

Gastric bypass procedures typically entail surgical restriction of the size of the stomach and rerouting or bypassing a proximal portion the intestine to reduce absorption of nutrients. A study of 20-years of gastric bypass patients found that 80% of those with type 2 diabetes before surgery no longer required insulin or oral agents to maintain normal glucose levels. Weight loss also occurred rapidly in many people in the study who had had the surgery. Unfortunately, gastric bypass procedures involve irreversible reconstruction of gastrointestinal anatomy and may be associated with significant adverse events, and/or mortality. In spite of the growth in the number of surgical procedures for weight loss (greater than 250,000 annually in the US), only 1.2% of eligible patients elect to undergo these invasive surgeries each year.

Many patients who could benefit from these procedures forego surgery due to the significant complications and high rates of long-term adverse events leading to poor quality of life. The estimated 0.3-2% mortality rate along with the 19% surgical complication rate for RYGB have been major barriers for expanding the use of surgery in broader patient populations.

In view of the foregoing, there is a need in the art for new devices and methods for controlling and treating obesity and type 2 diabetes.

SUMMARY OF THE INVENTION

The present invention provides systems, apparatus and methods for treating and/or controlling obesity and type II diabetes. In particular, the systems and methods of the present invention operate to decrease the rate that chyme flows through the GI tract while allowing natural peristalsis to occur.

In one aspect of the invention, a device for treating obesity includes a flow restrictor and an anchor coupled to the flow restrictor. The flow restrictor is movable between a first or collapsed configuration sized and shaped for endoscopic advancement through the patient's esophagus and into a distal region of the stomach and a second or operative configuration sized and shaped for inhibiting a flow of chyme from the stomach to the pyloric sphincter. It is believed that this will cause the prolongation of satiety, and result in fewer meals being eaten and/or smaller meals being ingested. The flow restrictor, simply by virtue of its inherent volume, may also reduce the amount of food required to reach satiety. Preferably, the flow restrictor is also sized and shaped in the operative configuration to prevent distal movement of the flow restrictor through the pyloric sphincter. The anchor is movable between a first or collapsed configuration sized and shaped for advancement through the esophagus, stomach and pyloric sphincter and into the proximal region of the duodenum and a second or operative configuration sized and shaped to inhibit proximal movement of the anchor through the pyloric sphincter.

A key advantage of the present invention is that the obesity device can be placed and removed endoscopically through the patient's esophagus in a minimally invasive outpatient procedure. In addition, the obesity device expands to fit securely against tissue within the GI tract such that the position of the device is substantially maintained throughout the digestive process. Thus, the device is “self-anchoring” and does not require invasive tissue fixation within the patient's GI tract, thereby reducing collateral tissue damage and minimizing its impact on the digestive process. Also, unlike other more invasive procedures such as gastric bypass, the obesity device of the present invention does not require any permanent restructuring of the GI anatomy. Once the device is removed, the patient's GI tract should being to function normally and in the same manner as if the device were never placed in the patient.

The flow restrictor is preferably coupled to the anchor by one or more flexible columns that extend through the pyloric sphincter in the operative position. The flexible columns allow both the flow restrictor and the anchor to move back and forth within the stomach and duodenum, respectively, with the natural peristalsis motion of the patient. In the preferred embodiments, the flow restrictor and the anchor will periodically or continuously apply slight contact pressure to the distal portion of the pyloric antrum and the proximal portion of the duodenum, respectively.

Another advantage of the present invention is that the slight contact pressure placed on the pyloric antrum and/or duodenum causes an increase in vagal nerve activity. The pyloric antrum and duodenum are innervated by the enteric nervous system and the parasympathetic nervous system (i.e., the vagus nerve). Many researchers have shown that the vagus nerve is responsible for the majority of afferent signals responsible for satiety. Thus, it is believed that increasing the afferent vagal nerve activity will result in satiety signals produced by the brain, making the patient feel more full and less inclined to eat. This provides an additional mechanism to treat obesity according to the present invention.

In a preferred embodiment, the flow restrictor comprises a substantially hollow structure, e.g., a balloon, defining an exterior wall and an interior. The balloon includes a fluid inlet, preferably with a one-way valve, for delivering a fluid into the interior of the balloon to inflate the balloon into the operative configuration after the balloon has been positioned within the patient's stomach. The flow restrictor will preferably have a shape in the inflated position that substantially corresponds to the anatomy of the distal region of the stomach or pyloric antrum. The exterior wall of the balloon may comprise a number of suitable biocompatible materials, such as silicone and the like. The fluid is preferably a biocompatible fluid, such as isotonic saline, that can be safely expelled into the patient's stomach upon removal of the device.

In one embodiment, the flow restrictor comprises a substantially conical shape. Preferably, the exterior wall of the flow restrictor comprises an outer membrane forming proximal and distal substantially planar surfaces and tapering in the longitudinal direction from the proximal to the distal surface. The distal surface will preferably have an outer diameter larger than the maximum diameter of the pyloric sphincter to prevent distal movement of the flow restrictor into the pyloric sphincter. In exemplary embodiments, the flow restrictor will further include stiffer components, such as ribs or bosses, extending along the outer membrane to provide support to the structure against the natural peristalsis forces within the stomach that will act against flow restrictor during operation.

In another embodiment, the flow restrictor in the inflated configuration comprises a substantially cylindrical central core section and one or more substantially annular flanges or projections that extend radially outward from the central core. In this embodiment, the flanges serve to correspond with the stomach anatomy. To that end, the proximal flange preferably has a larger diameter than the distal flange(s) and the distal most flange preferably has a diameter larger than the maximum diameter of the pyloric sphincter.

In an alternative embodiment, the flow restrictor is designed for expansion through mechanical methods (i.e., without the use of an inflation fluid). In one such embodiment, the flow restrictor defines a longitudinal axis and comprises at least one flange defining a central opening at the longitudinal axis and an outer surface spaced from the longitudinal axis. In some embodiments, the flow restrictor comprises a plurality of such flanges longitudinally spaced from each other. Each flange is movable between a first or operative position wherein the flange extends radially outward substantially perpendicular to the longitudinal axis and a second or compact position wherein the flange bends downward such that it forms an acute angle with the longitudinal axis. In the operative position, the flanges are designed to inhibit chyme flow from the stomach to the pyloric sphincter. In addition, the flanges have a larger outer diameter than the inner diameter of the pyloric sphincter thereby preventing distal movement of the flanges through the pyloric sphincter. In the compact position, the flanges can be bent downward to substantially reduce the diameter of the flow restrictor, allowing the flow restrictor to be advanced endoscopically through the patient's esophagus and into the stomach.

In this embodiment, the flanges preferably comprise one or more ribs housed within a relatively flexible covering or frame. The ribs are preferably stiff enough to provide support for the flexible covering in the operative position and will define a pivot point near the central opening of the flange to allow the ribs to pivot between the compact and operative positions (e.g., similar to an umbrella). In an exemplary embodiment, the ribs and covering are molded from a suitable biocompatible plastic, such as silicone. The ribs preferably have a durometer suitable for providing stiffness and support to the device, while the frame will have a softer durometer allowing flexibility and minimizing any adverse impact from tissue contact with the flanges.

In certain embodiments, the covering or frame of each of the flanges has a substantially annular shape. Alternatively, the frames may comprise multiple projections extending radially outward from the central opening, e.g., a rose petal shape, to facilitate folding down the frames into the compact configuration. In another embodiment, the frame may comprise slits extending radially outward from the central openings to achieve the same purpose. In any of these embodiments, the flow restrictor further comprises a locking mechanism for locking, biasing or otherwise securing the ribs in the operative position. This ensures that the flow restrictor will remain in the operative position while implanted in the patient. In one embodiment, the locking mechanism comprises a plurality of leaf springs coupled to the ribs that bias the ribs into the operative position. Alternatively, the locking mechanism may comprise a separate device that engages the ribs and pivots them into the operative position, such as a tube that is extendable through the central openings of each flange. In this latter embodiment, the frame of the flanges will each define an annular rim extending around the central opening. Each flange is pivotable around the central opening between the first and second positions such that when the tube is inserted through the central openings, the ribs are forced to pivot into the first position, where they will remain secured in position so long as the tube remains in place within the central openings of the flanges. When the tube is removed, the ribs are free to move such that the user can bend the flanges into the second position for insertion or removal into or from the patient.

The anchor comprises an expandable member coupled to the proximal opening of a substantially hollow tube. The tube preferably has a funnel shape such that its proximal opening is larger than its distal opening to correspond to the narrowing shape of the GI tract distal of the pyloric sphincter. The expandable member is designed to move the proximal end of the tube between a first or collapsed position sized and shaped for advancement through the pyloric sphincter into the duodenum and a second or operative position sized and shaped for anchoring against the pyloric sphincter at the proximal end of the duodenum to prevent movement of the anchor through the pyloric sphincter.

The expandable member is preferably designed to allow for movement from the collapsed position towards the operative position, while preventing the reverse movement back towards the collapsed position. This locks the anchor into the operative position after insertion into the patient. The expandable member may be biased towards the operative position, it may be inflated into the operative position or it may be designed to require a force applied to the expandable member to move it into the operative position. In one embodiment, the expandable member defines an exterior wall and an interior and includes a fluid inlet for delivering fluid into the interior to inflate the expandable member into the operative position. Preferably, the expandable member comprises a substantially annular shape in the inflated position with a central opening sized to allow chyme to pass therethrough with minimal flow restriction. The outer diameter of the expandable member will be larger than the maximum diameter of pyloric sphincter in the inflated configuration.

In an alternative embodiment, the locking member comprises a ratchet device that can be expanded outward with a force applied to the inner surface of the ratchet (e.g., from a separate balloon designed for such purpose). In alternative embodiments, the locking member comprises a bar member that is movable between a substantially spiral configuration to a substantially circular configuration. In exemplary embodiments, the locking member will have multiple operative positions such that the physician can appropriately size the anchor depending on the anatomy of the individual patient.

In certain embodiments, the obesity device further comprises a hollow sleeve or liner coupled to the anchor and sized and shaped to extend from the distal opening of the anchor through the duodenum and into a proximal portion of the jejunum of the patient. The sleeve is positioned such that partially digested food or chyme, moving through the digestive tract passes through the interior of the sleeve. This inhibits the absorption of nutrients/calories in the upper segments of the small intestine and delays mixing of chyme with digestive enzymes such that a quantity of food ingested by the patient will have a smaller caloric value with the sleeve in place.

In addition, several recent clinical studies have demonstrated that gastric bypass surgical procedures for treating obesity, including Roux-en-Y, bilio-pancreatic diversion and duodenum exclusion, show a rapid and remarkable reduction in clinical symptoms of diabetes including normalization of glucose and insulin levels. These effects occur before any changes in obesity and suggest that the duodenum may secrete molecular signals that cause insulin resistance. Supportive data has also been demonstrated in rat models of diabetes. See, Rubino and Marescaux, Annals of Surgery, 239 No. 1, 1-11 (January 2004), the entirety of which is incorporated herein by reference. Thus, the sleeve is designed to mimic the effects of bypassing the proximal portion of the small intestine seen in these surgical procedures. Specifically, it is believed that the sleeve will reduce hormonal triggers that may help to down-regulate the production of glucose, thereby resulting in a nearly immediate relief of Type-II diabetes symptoms. The stabilization or elimination of Type-II diabetes symptoms will have a beneficial impact on patient health and further increase weight loss.

A method for treating obesity according to the present invention comprises endoscopically advancing an anchor through the esophagus, the stomach and the pyloric sphincter and into a proximal region of the duodenum. The anchor is then expanded into an operative position that prevents proximal movement of the anchor back through the pyloric sphincter. A flow restrictor is advanced through the esophagus of a patient and into a region of the stomach proximal to the pyloric sphincter. The flow restrictor is expanded into an operative position that inhibits the flow of chyme from the stomach to the pyloric sphincter. The method further comprises the step of coupling the anchor to the flow restrictor, preferably with one or more flexible columns. This may occur prior to insertion of the device into the patient's esophagus, while both the anchor and flow restrictor are in the stomach, or after the anchor has been inserted into the duodenum.

In a preferred embodiment, the method includes inserting an overtube through the patient's esophagus and advancing the flow restrictor and anchor through the overtube into the stomach in the compact configurations under the visual guidance of an endoscope (preferably advanced through the same overtube, although it will be recognized by those of skill in the art that other methods of visualizing the procedure can be employed). A guidewire may be inserted through the tube prior to the device to help guide the device to the target location in the stomach. In this embodiment, the guidewire will extend through a central tube in the flow restrictor. The flow restrictor is preferably maintained in the collapsed configuration at this point by a second hollow tube or sleeve having an outer diameter smaller than the inner diameter of the overtube. This allows the physician to visualize the pyloric sphincter and duodenum with the scope.

Once in position within the stomach, the anchor is advanced via the guidewire into the proximal region of the duodenum. In certain embodiments, a sleeve coupled to the anchor is then extended through the length of the duodenum and a portion of the jejunum. The anchor is then expanded into its operative configuration. Preferably, this step is carried out by delivering fluid through a fluid tube into the interior of an expandable member of the anchor and then detaching the fluid tube from the anchor and removing it from the patient.

After the anchor has been expanded into the operative position, the flow restrictor is removed from the second tube and expanded into its operative position. In the preferred embodiment, fluid is delivered through a fluid tube into the interior of the flow restrictor to expand the flow restrictor. As with the anchor, the fluid tube is then detached and removed from the patient.

Other aspects, features, advantages, etc. will become apparent to one skilled in the art when the description of the invention herein is taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the present invention, systems, devices and methods are disclosed for treating and controlling obesity and/or type II diabetes. In particular, the systems and methods of the present invention provide an internal bypass of a proximal portion of the small intestines to inhibit contact between chyme and the bypassed small intestinal walls while allowing natural peristalsis to occur. The present invention is related to co-pending patent application Nos. 61/123,472 filed Apr. 9, 2008; 61/206,048 filed Jan. 27, 2009; Ser. No. 12/420,219 filed Apr. 8, 2009; Ser. No. 12/384,889 filed Apr. 9, 2009; Ser. No. 12/384,890 filed Apr. 9, 2009 and Ser. No. 12/384,898 filed Apr. 9, 2009, the full disclosures of which were previously incorporated herein by reference.

Diabetic foot ulcers are one of the major complications of diabetes mellitus. Foot ulcers occur in 15% of all patients with diabetes and precede 84% of all lower leg amputations. The significant increase in mortality among diabetic patients with foot ulcers observed over the past 20 years is considered to be due to the development of macro and micro vascular complications, including failure of the wound healing process.

Wound healing is a ‘make-up’ phenomenon for the portion of tissue that gets destroyed in any open or closed injury to the skin. Being a natural phenomenon, wound healing is usually taken care of by the body's innate mechanism of action that works reliably most of the time. The key feature of wound healing is the stepwise repair of lost extracellular matrix (ECM) that forms the largest component of the dermal skin layer. Therefore, controlled and accurate rebuilding becomes essential to avoid under or over healing that may lead to various abnormalities. But in some cases, certain disorders or physiological insults disturb the wound healing process that otherwise proceed smoothly in an orderly manner. Diabetes mellitus is one such metabolic disorder that impedes the normal steps of wound healing process. Many histopathological studies show a prolonged inflammatory phase in diabetic wounds, which causes a delay in the formation of mature granulation tissue and a parallel reduction in wound tensile strength.

High blood sugar levels prevent white blood cells, which are important in defending the body against bacteria and also in cleaning up dead tissue and cells, from functioning normally. When these cells do not function properly, wounds take much longer to heal and become infected more frequently. Also, long-standing diabetes is associated with thickening of blood vessels, which prevents good circulation including the delivery of enough oxygen and other nutrients to body tissues.

Another consequence of high blood sugar levels is that the body has difficulty producing many important components in the healing process, such as vascular endothelial growth factors (VEGF) and nitric oxide. For example, nitric oxide is known as an important stimulator of cell proliferation, maturation and differentiation. Thus, nitric oxide increases fibroblast proliferation and thereby collagen production in wound healing. Also, L-arginine and nitric oxide are required for proper cross linking of collagen fibers, via proline, to minimize scarring and maximize the tensile strength of healed tissue. Endothelial cell specific nitric oxide synthase (EcNOS) is activated by the pulsatile flow of blood through vessels. Nitric oxide produced by EcNOS, maintains the diameter of blood vessels and proper blood flow to tissues. In addition to this, nitric oxide also regulates angiogenesis, which plays a major role in wound healing.

Diabetic patients exhibit reduced ability to generate nitric oxide from L-arginine. Reasons that have been postulated in the literature include accumulation of nitric oxide synthase inhibitor due to high glucose associated kidney dysfunction and reduced production of nitric oxide synthase due to ketoacidosis observed in diabetic patients and pH dependent nature of nitric oxide synthase.

The present invention provides systems, apparatus and methods for treating wounds in patients, particularly chronic lower limb wounds in patients lacking the innate ability to regulate glucose (e.g., diabetic patients). In one aspect of the invention, a method for treating wounds includes positioning a flexible sleeve within the patient such that the sleeve extends through at least a portion of the duodenum to inhibit contact between chyme passing therethrough and at least a portion of an inner surface of the duodenum. The hollow sleeve is maintained within the duodenum for a sufficient period of time to reduce a blood glucose level in the patient. Preferably, the sleeve will be maintained in position for a sufficient period of time to permit the normalization of blood glucose levels in the patient (i.e., reducing such glucose levels to below about 150 mg, preferably below about 125 mg).

The sleeve creates an “internal bypass” that substantially inhibits contact between chyme and other substances entering the duodenum from the stomach of the patient and the bypassed portion of the duodenum. This reduces hormonal triggers that help to down-regulate the production of glucose, thereby resulting in the relief of certain symptoms that inhibit the body from effectively healing the wound, such as decreased peripheral vascular perfusion, neuropathy, a compromised or “inactive” immune system and a reduction in important components of healing, such as nitric oxide, vascular endothelial growth factors and the like.

In certain embodiments, the sleeve will be maintained in position for a sufficient period of time to increase the peripheral vascular perfusion in the patient. Patients lacking the innate ability to regulate glucose levels often suffer from decreased arterial perfusion of the extremities. The lack of blood flow to the extremities inhibits healing of wounds, such as foot ulcers and the like. In one embodiment of the present invention, the flexible sleeve is held in position within the duodenum until this process begins to reverse, thereby increasing peripheral vascular perfusion and allowing for accelerated healing of the wound.

In other embodiments, the sleeve will be maintained in position for a sufficient period of time to elevate an immune system response in the patient. Abnormally high glucose levels cause the body's immune system to become compromised or less active than normal. The white blood cells or leukocytes of the immune system that defend the body against infection become sluggish and unable to effectively fight infections, such as those associated with wounds. In this embodiment, the flexible sleeve is held in position within the duodenum until the activity of circulating leukocytes begins to substantially increase, which allows the patient's immune system to do its natural job of fighting the infection and accelerate healing of the wound.

In other embodiments, the flexible sleeve is maintained in position for a sufficient period of time to increase certain healing factors, such as nitric oxide and vascular endothelial growth factors (VEGF) in the patient. VEGF is an important signaling protein that stimulates the growth of new blood vessels, which can be a critical part of the angiogenesis process in wound healing. In one embodiment of the present invention, the flexible sleeve is held in position within the duodenum until a sufficient amount of VEGF are produced in the patient to accelerate healing of the wound.

In other embodiments, the flexible sleeve will be maintained in position for a sufficient period of time to halt or reverse neuropathy. Diabetic neuropathy is a common complication of patients lacking the innate ability to regulate glucose in which nerves are temporarily or permanently damaged as a result of high blood sugar levels (hyperglycemia). Neuropathy can complicate the wound healing process, particularly in the extremities. In this embodiment, the sleeve is held in position until nerves that have not been permanently damaged or destroyed can be repaired by the body to accelerate healing of the wound.

In a preferred embodiment, the flexible sleeve is sized and shaped to extend from the distal opening of the duodenal anchor through at least a portion of the duodenum (i.e., between about 4-12 inches). In some embodiments, the sleeve may extend throughout the duodenum and into a proximal portion of the jejunum of the patient (i.e., between about 12-30 inches, preferably about 12-16 inches). The sleeve is substantially hollow and positioned such that partially digested food, i.e. chyme, moving through the digestive tract passes through the interior of the sleeve. This inhibits the absorption of nutrients/calories in the upper segments of the small intestine and delays mixing of chyme with digestive enzymes such that a quantity of food ingested by the patient will have a smaller caloric value with the sleeve in place. In addition, it is believed that the sleeve inhibits certain hormonal triggers that would otherwise occur when food passes through the duodenum and proximal jejunum; hormonal triggers that cause the body to become insulin resistant and result in type 2 diabetes.

In certain embodiments, the sleeve is removably introduced through a natural orifice in the patient into the small intestines, preferably endoscopically through the patient's esophagus, stomach and pylorus. The sleeve can be maintained in position within the duodenum in a variety of ways known to those of skill in the art (e.g., sutures, hooks, barbs, atraumatic anchoring mechanisms and the like), typically for about 2 weeks to one year, preferably between about 1 month to 6 months and more preferably between about 6-12 weeks.

In a preferred embodiment, the sleeve is maintained in position with a pair of anchor elements flexibly coupled to each other and the sleeve. In the preferred embodiment, the flexible anchors are endoscopically introduced with the sleeve and positioned on either side of the pylorus. The duodenal anchor element is preferably expanded to a size that will inhibit proximal movement of the duodenal anchor through the pyloric sphincter to ensure that the sleeve remains in the patient's intestines. Likewise, the gastric anchor element is expanded to a size that will inhibit or prevent distal movement through the pyloric sphincter to ensure that the device does not pass further into the intestines and create a blockage. In a preferred embodiment, the anchor elements are expanded by delivering a fluid into each anchor element to inflate said anchors. In other embodiments, the anchor elements may be expanded mechanically or by other suitable means.

Referring to the drawings, wherein like reference numerals refer to like elements, there is shown inFIG. 1an example of a portion of a GI tract10of a human body. Two smooth muscle valves, or sphincters, contain the contents of the stomach within the stomach upon ingestion. They are the esophageal sphincter (not shown), found in the cardiac region above the antrum cardiacum, and the pyloric sphincter20, disposed between the stomach30and the small intestine40. The pylorus20is the region of the stomach30that connects to the duodenum50. The pylorus20is divided into two parts: the pyloric antrum60which connects the body to the stomach and the pyloric canal which connects to the duodenum50. The pyloric sphincter20is a strong ring of smooth muscle at the end of the pyloric canal that functions to help regulate the passage of chyme from stomach30to the duodenum50.

Satiety receptors80are generally located all along the inside lining of stomach tissue. Partially undigested food in GI tract10is generally referred to as chyme. If chyme remains in the region of the stomach before flowing into small intestine40, satiety receptors80have a greater chance of being activated, which enhances the ability of an overweight or obese patient to feel satiated and suppresses the desire to eat.

Pyloric antrum60and duodenum50are innervated by the enteric nervous system and the parasympathetic nervous system (i.e., the vagus nerve). Many researchers have shown that the vagus nerve is responsible for the majority of afferent signals responsible for satiety. Thus, it is believed that increasing the afferent vagal nerve activity will result in satiety signals produced by the brain, making the patient feel more full and less inclined to eat.

A bypass device according to any of the below-described embodiments is preferably comprised of a polymeric structure that is compliant and generally flexible and bendable. Preferably, at least a portion of the device is made of silicone, flourosilicone or other similar biocompatible material capable of prolonged exposure to the stomach and intestines. Some portions of the device may be thicker than others for enhanced strength properties and to enhance the capability of the device to resist the natural peristaltic action of GI tract10. Alternatively, some portions of the device may be thinner than others to allow for the material peristaltic actions of GI tract10to occur without the device providing a counteractive force. Preferably, if a portion of the device is bent or twisted during insertion, its polymeric structure will allow it to revert back to its resting or initial shape.

The one or more materials that comprise a bypass device according to the present invention are preferably selected for their ability to yield and flex during implantation and removal of the device. These properties also protect the patient and the tissues and organs with which the device comes into contact. The compliant nature of the bypass device allows its configuration to be manipulated during a surgical procedure, preferably in such a way that the device tends to revert to its operative configuration. The device may be made of shape memory material, such as nitinol or other known pliable polymeric materials, to allow for expansion back into its operative configuration. Any or all of the device may be coated with Teflon to provide a smooth outer surface to reduce friction between the device and the patient during implantation and removal.

The bypass device according to the present invention is structured to inhibit the rate that chyme passes through GI tract10, thereby enhancing the ability of chyme to activate satiety receptors80and effectively enhance satiety in a patient. In particular, the device is preferably structured to reduce the rate of gastric emptying such that obesity can be controlled by controlling satiety.

The bypass device of the present invention is also designed to provide periodic or continuous contact pressure on the pyloric antrum and or the proximal portion of the duodenum. This contact pressure modulates (preferably stimulates) one or more nerves within these two structures, thereby increasing their activity. In certain embodiments, this contact pressure is brought about by the design of the device; namely, the flow restrictor and anchor are coupled to each other by flexible elements or columns (discussed in detail below). These flexible columns are sized such that the anchor generally rests against the proximal portion of the duodenum and the flow restrictor generally rests against the distal portion of the pyloric antrum. The flexible columns also have enough “give” or flexibility to allow the anchor and flow restrictor to move back and forth with the peristaltic motion of the GI tract. Thus, the anchor and flow restrictor may periodically move away from the proximal portion of the duodenum and the distal portion of the pyloric antrum, respectively. However, they will generally move back in contact with these structures to provide at least periodic pressure contact on these structures to stimulate the parasympathetic nerves therein.

The bypass device is also designed to inhibit contact between chyme passing through the duodenum and the inner walls of the duodenum. This inhibits the absorption of nutrients/calories in the upper segments of the small intestine and delays mixing of chyme with digestive enzymes such that a quantity of food ingested by the patient will have a smaller caloric value with the sleeve in place. In addition, this reduces hormonal triggers that may help to down-regulate the production of glucose, thereby resulting in a nearly immediate relief of Type-II diabetes symptoms. The stabilization or elimination of Type-II diabetes symptoms will have a beneficial impact on patient health and further increase weight loss.

Incretins are gastrointestinal hormones, produced in response to the transit of nutrients, that boost insulin production. Because an excess of insulin can determine hypoglycemia (extremely low levels of blood sugar)—a life-threatening condition, it has been speculated that the body has a counter-regulatory mechanism (or “anti-incretin” mechanism), activated by the same passage of nutrients through the upper intestine. The latter mechanism would act to decrease both the secretion and the action of insulin. Thus, in healthy patients, a correct balance between incretin and anti-incretin factors maintains normal excursions of sugar levels in the bloodstream. In some individuals, however, the duodenum and jejunum may be producing too much of this anti-incretin, thereby reducing insulin secretion and blocking the action of insulin, ultimately resulting in Type 2 diabetes.

Indeed, in Type 2 diabetes, cells are resistant to the action of insulin (“insulin resistance”), while the pancreas is unable to produce enough insulin to overcome the resistance. After gastrointestinal bypass procedures, the exclusion of the upper small intestine from the transit of nutrients may offset the abnormal production of anti-incretin, thereby resulting in remission of diabetes. However, it should be noted that the scientific community has not settled on a particular mechanism of action that causes patients undergoing such bypass procedures to become less “insulin resistant”. Thus, the present invention is not limited to this particular mechanism of action or any particular mechanism of action.

Certain components of the bypass device according to the present invention may be discussed as being attached or connected to one another. Preferably, the device is constructed of one continuous piece and of one material, preferably silicone. However, two or more components of the device may be manufactured separately and subsequently assembled. If assembled, components may be glued together using a silicone-based glue.

FIG. 2illustrates one preferred embodiment of a bypass device100according to the present invention. As shown, device100includes a gastric anchor102coupled to a duodenal anchor104by a plurality of flexible silicone tethers or pyloric columns106and a hollow sleeve108coupled to the distal end of duodenal anchor104. Pyloric columns106are designed to extend through the pyloric sphincter20to allow both gastric anchor102and duodenal anchor104to have some limited movement back and forth within the stomach30and duodenum50, respectively, with the natural peristalsis motion of the GI tract (seeFIG. 16). Pyloric columns106may be cylindrical or any other type of prismic shape and are preferably designed such that the distance between the distal end of gastric anchor102and the proximal end of duodenal anchor104is about 10-60 mm, preferably about 20-40 mm, and more preferably about 30 mm, in the fully extended, but relaxed condition (i.e., non-elastically extended). Preferably, device100includes at least two, preferably three, pyloric columns106each having a diameter of about 1-5 mm which are attached to the inside surfaces of anchors102,104. Alternatively, anchors102,104may be coupled together with a hollow sleeve that extends through the pyloric sphincter20. The sleeve would preferably be sufficiently flexible to allow sphincter20to open and substantially close without hindrance from the sleeve.

FIG. 3illustrates a cross-sectional perspective view of an exemplary embodiment of gastric anchor102. As shown, gastric anchor102includes an internal ring110coupled to an annular inflatable membrane112having a substantially annular or toroidal shape. Inflatable membrane112comprises an outer wall114surrounding a hollow interior116configured for inflation via a suitable fluid. Ring110and membrane112preferably comprise a flexible biocompatible material, such as a phosphlipid resistant silicone material (e.g., a fluorosilicone copolymer). Alternatively, ring110may comprise a water-absorbent material, such as a hydrogel, that expands and hardens upon contact with fluid. Ring110provides structural support for anchor102, while inflatable member112allows anchor102to move between a collapsed configuration for introduction through the patient's esophagus and an expanded configuration within the stomach. Thus, ring110is preferably harder and less flexible than inflatable membrane112having a durometer of at least about 70 A, preferably greater than about 80 A, while membrane112preferably has a durometer between about 30-60 A, more preferably between about 40-60 A.

In an alternative embodiment, anchor102may simply include an inflatable member112without support ring112. In this embodiment, the inflatable member112would be inflated to a size and pressure sufficient to withstand peristalsis forces without compressing to a size that would allow the anchor102to pass through pyloric sphincter20.

Gastric anchor102further includes a fluid inlet120for delivery of a fluid into hollow interior116of membrane112. In the preferred embodiment, fluid inlet120comprises a valve122formed along the inner circumference of ring110and extending into interior116of membrane. As shown, valve122includes small chamber124in which a hole126is formed. Hole126extends radially from the inner surface of ring110, through ring110, into interior116of membrane112. A flexible silicone flap128, formed as part of the interior surface of the inflatable member112, is located adjacent to hole126. Silicone flap128serves to occlude hole126once the pressure within interior116of inflatable member112exceeds the pressure exterior to the member112, thereby forming a one-way valve to prevent fluid egress from membrane112.

In addition to, or as an alternative to, the one-way valve, a curable fluid, such as silicone, may be injected into the fluid pathway after the saline. The curable fluid will cure and harden, thereby preventing any fluid egress from the interior of inflatable member112. In another embodiment, the inflatable members of the anchors may comprise a material that self-seals when punctured with a very sharp small instrument such as a syringe. In this embodiment, the inflatable members of the bypass device may simply be inflated with a syringe and then self-sealed by the material to prevent fluid egress.

In the preferred embodiment, ring110has an inner diameter of about 10-50 mm, preferably about 20-40 mm, and more preferably about 30 mm, and a thickness of about 1-5 mm, preferably about 3 mm. Inflatable membrane112has an outer diameter of about 30-70 mm, preferably about 40-50, and more preferably about 45 mm, when the pressure within membrane112is equal to the pressure outside (the state of nominal inflation, i.e., complete inflation without elastic deformation). In the preferred embodiment, however, membrane112is designed such that fluid can be injected into interior116until it has expanded significantly beyond the initiation of elastic deformation, with a maximum exterior diameter of the implanted gastric portion preferably being between about 50 and 60 mm.

Duodenal anchor104preferably has a similar structure as gastric anchor102; including an inner ring130and an annular inflatable membrane132having a substantially annular or toroidal shape (seeFIG. 2). Inflatable membrane132is designed to inflate into a substantially annular shape that provides for a secure anchor against the distal opening of the pyloric sphincter. This ensures that anchor104will remain in place within the duodenum50despite the natural peristalsis forces acting against anchor104. Anchor104further includes a valve structure134(similar in design to gastric anchor102) for delivering a fluid into an interior of membrane132to inflate membrane132. In the exemplary embodiment, ring130has an inner diameter of between about 10-20 mm, preferably about 15 mm, a thickness of between about 1-5 mm, preferably about 3 mm. Inflatable membrane132preferably has an outer diameter of between about 20-30 mm, preferably about 25 mm, when the pressure within membrane132is equal to the pressure outside (the state of nominal inflation, i.e., complete inflation without elastic deformation). Similar to the gastric component, membrane132is designed for inflation beyond the initiation of elastic deformation, with a maximum exterior diameter of the implanted duodenal anchor being between about 30 and 50 mm, preferably between about 35 to 40 mm.

In an alternative embodiment, gastric and duodenal anchors102,104include one or more expandable components that either completely or partially replace the fluid used in the previous embodiment to inflate or expand anchors102,104. In a preferred embodiment, the expandable components comprise fluid-absorbent materials designed to expand upon contact with certain fluid, such as hydrogels. Hydrogels are networks of polymer chains that are water-insoluble and hydrophilic. In this embodiment, a plurality of hydrogel components (not shown) are housed within the inflatable members of anchors102,104. The hydrogel components will be introduced into the patient in the “dry” or smaller state within anchors102,104. A fluid, such as saline, is delivered into the interior of the inflatable members and is absorbed within the hydrogel components (which may be of any shape, such as spheres or the like) to expand these components, thereby expanding the inflatable members.

In one aspect of this embodiment, the anchors102,104include a plurality of hydrogel beads, preferably about 0.5 to 3.0 mm in diameter, designed to expand to a larger size (e.g., about 4-6 mm in diameter) upon hydration with a fluid, such as saline. In this embodiment, anchors102,104may or may not include inner rings110and they may not require one-way valves. The hydrogel balls provide additional rigidity to the anchors102,104. In addition, they provide additional safety in the event that the inflatable members are punctured with a small hole as the balls will remain within inflatable members in such event (as opposed to a puncture that will allow all of the fluid to exit inflatable members in the previous embodiments). Upon removal of the device, the inflatable members will be punctured with a large enough hole to allow the hydrogel balls to exit the interiors of the inflatable members. The hydrogel balls can be allowed to pass through the patient's GI tract and excreted naturally.

FIG. 4illustrates an alternative embodiment of gastric anchor102. In this embodiment, anchor102is substantially similar in design and construction as the anchor shown inFIG. 2, comprising a central support ring110surrounded by an inflatable member112having an internal valve120. However, this anchor102also includes an internal restrictor plate150attached to support ring110. Plate150has a central hole151designed to allow chyme to pass therethrough. Plate150serves to substantially inhibit the flow of chyme from the stomach to the pyloric sphincter. It is believed that this will cause the prolongation of satiety, and result in fewer meals being eaten and/or smaller meals being ingested. The inner diameter of hole151will vary depending on the rate of chyme flow desired for the individual patient. For example, hole151may have a diameter of about 5-20 mm.

Referring toFIG. 5, sleeve108may be manufactured to any length according to a particular patient and/or surgical procedure, and in the preferred embodiment includes at its distal end a beveled tip109. Along its length, sleeve108may have one or more side holes113which provide further access for chyme to enter sleeve108. In some embodiments, a rib131is disposed along sleeve108and is preferably substantially parallel to the longitudinal axis of sleeve108, though rib131may extend only partially along sleeve108and may take on a curved or other type of orientation with respect to the longitudinal axis. Rib131may be comprised of silicone and additionally may include a radiopaque material, such as barium, so that rib131may be detected by a fluoroscope. Rib131may be provided as a separate component and later attached to sleeve108, or rib131may essentially be the overlapping seam formed during the manufacture of sleeve108when a flat piece of material is rolled into a tubular shape. In such a configuration, sleeve108may be comprised of a homogenous material attached by a radiopaque glue. Of course, as rib131is primarily used as an aid during implantation and/or removal of obesity device100, rib131need not necessarily be included in this or any other embodiment according to the present invention.

Sleeve108preferably has a diameter that will substantially correspond with the inner diameter of the patient's duodenum and a length that will allow the sleeve to extend into at least the proximal portion of the jejunum depending on the individual patient's anatomy. Thus, sleeve108will typically have a length of between about 20-80 cm, preferably between about 55-75 cm, a thickness of about 0.05 mm to 0.22 mm and a diameter of between about 1 to 3 cm, preferably about 2.5 cm. Preferably, the proximal portion of sleeve108has an inner diameter of about 1.2 cm that expands laterally in the proximal direction to 1.5 cm so that it may be sealed to the lower surface of anchor104. The material of the sleeve is preferably silicone, such as a polyethylene-reinforced silicone.

Sleeve108may include one or more markers (e.g., barium) designed for viewing the position of the sleeve within the intestines through fluoroscopy, such as rib131or other markers that are spaced along the length of sleeve108. In addition, sleeve108may further include components that inhibit twisting or kinking of the sleeve108. In one embodiment, these components include one or more stiffening elements, such as rings, coupled to either the inside or the outside of the sleeve at spaced locations along its length. These rings can, for example, be made of a slightly thicker silicone material that would resist twisting or kinking of the sleeve around the ring. In other embodiments, the stiffening elements may be in spiral shape or extending lengthwise along at least a portion of the sleeve108.

Sleeve108may also include one or more internal lumens extending along a portion of or the entire length of the sleeve. The fluid lumens comprise a proximal end configured for coupled to a fluid delivery system to allow a fluid to flow through sleeve to extend sleeve through the patient's duodenum and/or to ensure that sleeve remains patent without any twists or kinks along its length. In one embodiment, the sleeve comprises multiple (e.g., 2-5) internal lumens extending from the proximal to the distal end of the sleeve and spaced from each other around the circumference of the sleeve. In another embodiment, the sleeve comprises an internal lumen that extends in a spiral pattern down the length of the sleeve.

In yet another alternative embodiment, sleeve108may further include one or more fluid chamber(s) coupled to one or more of the internal lumens. The fluid chamber(s) facilitate implantation of the sleeve within the patient by allowing the physician to at least partially fill one or more of the chambers before withdrawing the scope from the duodenum (discussed in more detail below). In addition, the fluid chambers provide stiffness to the sleeve to provide more stability to the sleeve and ensure that it remains in place within the patient after implantation. The fluid may also include a material that is observable under fluoroscopy (e.g., barium or the like) such that the location of the internal lumens and/or the fluid chambers can be viewed by a physician after implantation.

In one embodiment, the fluid chamber comprises an annular passage extending around the circumference of the sleeve at or near its distal end. This configuration provides the additional advantage that, when filled, the annular fluid chamber provides a distal anchor for the sleeve and the entire bypass device to provide additional against proximal migration of the sleeve and/or device. In another embodiment, the sleeve comprises multiple annular fluid chambers spaced along the length of the sleeve to provide additional rigidity to the sleeve, thereby ensuring that the sleeve remains patent and preventing any kinking or twisting along its length.

In an alternative implantation method, the sleeve108may be initially folded “accordion-style” and tucked into the interior of the anchor104. The distal end of sleeve108is initially closed, with a small silicone rubber knob (not shown) attached to the bottom of sleeve108(e.g., like a “sock” with a ball on the inside surface of the “toe”). Just proximal to the ball, at a region where the diameter of sleeve108is about 2.1 cm, is a circumferential perforation (not shown) such that the ball and the “toe portion” of the sleeve will tear away from sleeve108leaving an open tubular sleeve behind.

Referring now toFIGS. 6 and 7, an alternative embodiment of a duodenal anchor230will now be described. As shown, anchor230comprises an annular support ring240coupled to an inflatable flexible membrane242. In this embodiment, support ring240comprises two flat ring elements244connected together by a semi-rigid central ring246that holds the flat ring elements244apart from each other. Flat ring elements244and central ring246preferably comprise a suitable material, such as silicone, which may be molded as one-piece or molded separated and glued together with a suitable silicone glue. Flat ring elements244are preferably separated from one another by a distance of about 8-12 mm. Flexible membrane242is sealed to the exterior circumferential surfaces of flat ring elements244and central ring246. Membrane242is initially tucked in a space250between flat ring elements244with sufficient additional material such that when saline is injected into the interior of membrane242, an inflated “inner tube” structure is created. This inner tube structure is intended to inflate to a maximum diameter of between 30-45 mm (depending on the specific duodenal anatomy of a given patient).

A one-way valve252is disposed between ring elements244at one location around the circumference thereof and directed inwardly. This valve252is initially coupled to a thin tube (not shown) that extends up along the exterior of the gastric anchor through which membrane242can be inflated. In an exemplary embodiment, a small wire (not shown) is incorporated into the seal of the inner membrane242to the rings to permit simple and rapid deflation of membrane242for removal of the device. A small ball (not shown) may also be coupled to the wire and located external to ring elements244and membrane242for grasping by an endoscopic instrument. Pulling the ball causes the wire to tear through membrane242and the seal, thus rupturing membrane242and collapsing anchor230.

Referring now toFIGS. 8-10B, bypass device100further comprises a deployment system200for facilitating the deployment of device100. As shown inFIGS. 8 and 9, deployment system200includes a proximal housing or capsule202and a distal housing or capsule204. Capsules202,204both comprise a biocompatible dissolvable material, such as gelatin and the like, designed to dissolve within the patient's body. As shown inFIG. 8, distal capsule204is sized and shaped to house sleeve108in a folded, compressed or collapsed configuration and duodenal anchor104in its collapsed or deflated configuration (seeFIG. 10A). Distal capsule204is open at its proximal end, and has a bullet-shaped distal tip208with a small hole206. Distal tip208is designed to facilitate passage of the capsule202(and sleeve108and anchor104therein) through the pylorus and into the duodenum. Hole206is sized and shaped for passage of a guidewire therethrough (seeFIGS. 11-15). Capsule202is preferably about 80-160 mm long (preferably about 100-140 mm long) about 10-30 mm wide (preferably about 20 mm) and is preferably constructed to survive for less than 30 minutes before dissolving in the human intestines.

As shown inFIG. 9, proximal capsule202is sized and shaped to house gastric anchor102in its collapsed configuration and at least a portion of columns106therein (seeFIG. 10A). Proximal capsule202is substantially cylindrically shaped and is primarily designed to facilitate passage of these components through the esophagus to minimize any damage to the inner walls of the esophagus. To that end, capsule204has a slightly curved distal end205with an opening207that is larger than distal opening206of distal capsule204to accommodate the various components of bypass device100therethrough, such as flexible columns106; delivery structure150and fluid tube210(seeFIG. 10B). In the preferred embodiment, capsule202is about 30-70 mm long (preferably about 50 mm) and about 10-30 mm wide (preferably about 20 mm). Capsule202preferably comprises a material that will dissolve in less than 15 minutes within the human stomach, such as gelatin and the like. Alternatively, capsules202,204may comprise a resorbable material or a material that can be safely excreted by the patient.

Referring now toFIGS. 10A and 10B, deployment system200further includes fluid tubes210,212coupled to valves122,134of gastric and duodenal anchors, respectively. Tubes210,212each include small one-way valves (not shown), such as an umbrella valve or a duckbill valve, formed in their distal tips. Tubes210,212are preferably coupled to valves122,134such that their own own-way valves are formed within the small chambers124of valves122,134. Upon inflation of the respective components, the tubes210,212are then cut proximal to valves122,134such that their one-way valves provide additional protection to ensure that fluid injected into the inflatable membranes112,132cannot escape through the holes.

Deployment system200further comprises a central tube structure150designed to extend through bypass device100(i.e., through the center of gastric and duodenal anchors102,104and sleeve108). Central tube structure150has a support tube152with an inner lumen (not shown) sized for passage of a guidewire therethrough (discussed in detail below). Support tube152has an inner diameter of at least 2.8 mm and preferably about 3 mm. Support tube152extends through hole206in distal capsule204and preferably has widened distal tip155designed to engage the outer surface of distal tip208of capsule204. This facilitates passing of guidewire into the distal opening of support tube152. Alternatively, support tube152may comprise an enlarged distal end (not shown) having a larger diameter than hole206that is located within capsule204. In this embodiment, the enlarged distal end of support tube152operates to push against capsule to propel capsule204forward as it advances through the patient's GI tract. Support tube152preferably comprises a material that has sufficient flexibility to easily navigate the patient's small intestines, yet sufficient rigidity to allow for a pushing force from outside of the patient's body to advance tube152and the rest of bypass device100through the patient's GI tract (discussed below). Suitable materials for support tube152are polypropylene and the like.

Central tube structure150further comprises a flexible tube154extending alongside support tube150. Flexible tube154houses a wire156coupled to a snare or a clamp158at its distal end. An actuator, such as a handle160(seeFIG. 12), is coupled to the proximal end of wire156for opening and closing clamp158. As discussed below, flexible tube154and clamp158are designed to facilitate advancement of sleeve108through the patient's small intestines to its final deployment position. Note that flexible tube154and support tube152may alternatively comprise a single tubular structure with two separate lumens (one for wire156and one to accommodate the guidewire).

In one embodiment, sleeve108comprises one or more small extensions or polyps (not shown) extending from its distal tip. In this embodiment, tube154includes a distal tip (not shown) with a clamp or fastener designed to fasten to the polyps to facilitate advancement of sleeve108as discussed above. When the sleeve is in its final deployment position, an actuator on handle on the proximal end of the tube154allows the use to pull the clamp proximally relative to the distal tip to sever the polyps and thereby detach tube154from the sleeve108. At this point, central tube structure150can be removed from the patient. The polyps will then pass through the patient's GI tract in a normal manner.

In an alternative embodiment, deployment system200includes a thin, hollow sheath coupled to a silicone ball (not shown). The ball is detachably coupled to the distal end of sleeve108and the sheath extends through sleeve108and duodenal and gastric anchors102,104. The ball has an axial hole formed therethrough aligned with the axial bore of the sheath. The axial bore of the flexible sheath has a length of about 120 mm, and an outer diameter of about 5 mm. The sheath and ball together allow the user to advance sleeve108through the intestines to its final deployment position.

In reference toFIGS. 11-16, a method of implanting and removing a bypass device100according to the present invention will now be described. While the description of this method will be specifically directed to the embodiments illustrated inFIGS. 2 and 3, it will be understood by those skilled in the art that this method (or similar methods) can be used to implant and remove all of the embodiments of the present invention, including embodiments or designs that may not be specifically described or illustrated herein.

Device100enters and exits the patient through esophagus302and is ultimately positioned in its operative state, wherein pyloric columns106extend through pyloric sphincter20(e.g., seeFIG. 15). Initially, a gastroscope306is lubricated, inserted into patient's mouth307, and fed through esophagus302and the gastroesophageal (“GE”) junction into stomach30, as shown inFIG. 11. Gastroscope306is preferably approximately 9.8 millimeters in length, and preferably has approximately a 2.8 millimeter working channel and suitable viewing and recording equipment, for example. It will be understood that tools and components that are described as being passed through or inserted into gastroscope306are passed through or inserted into its working channel. A lubricant such as Surgilube or equivalent may be provided as needed to lubricate the bypass device and/or any of the associated surgical equipment.

Gastroscope306should ultimately be positioned such that its distal end308is adjacent to pyloric sphincter20. Preferably, a guidewire322is hydrated and inserted through gastroscope306. Guidewire322is passed through pyloric sphincter20, which may be aided by manipulation of gastroscope306. It may also be beneficial to pass a distal end308of gastroscope306through pyloric sphincter20in order to maneuver guidewire322through same. There should preferably be at least about 30-40 centimeters of the length of guidewire322passed distally through pyloric sphincter20and into small intestine40so that any further movement of guidewire322during the insertion procedure does not result in the accidental removal of the distal end of guidewire322to a position proximal of pyloric sphincter20. Of course, the length of guidewire322that should preferably be passed distally through pyloric sphincter20may vary according to different patients and/or procedures and may be less or more than 30-40 centimeters. After guidewire322is appropriately positioned, gastroscope306is removed from the patient.

Referring now toFIG. 12, bypass device100and delivery system200are lubricated and positioned over the guidewire322outside of the patient by advancing the proximal end of guidewire322through hole206in distal capsule204and into the inner lumen of support tube152(seeFIG. 10A). In some embodiments, an overtube (not shown) may be positioned over the guidewire322and advanced through the esophagus and into the patient's stomach. The overtube typically has an inner diameter of approximately 16 mm. However, in the preferred embodiment, an overtube is not required for implantation of bypass device100. A small steerable scope (not shown) may be advanced through the esophagus into stomach30through the pylorus and into the proximal portion of the duodenum. The scope is used to confirm the tissue of the stomach, pylorus and duodenum are robust and show not overt signs that they will not tolerate the device. In an exemplary embodiment, a small tube (not shown) may be inserted into the pylorus. The tube includes a distal inner tube-shaped balloon (not shown) that expands to a known diameter with a known volume of saline. In conjunction with the scope images and other prior imaging data, this instrument is used to determine the appropriate size of bypass device100to be used, particularly the appropriate size of duodenal anchor.

Referring now toFIG. 12, once the appropriate size bypass device100is selected, distal capsule204(containing sleeve108and duodenal anchor104) and proximal capsule202(containing gastric anchor102and at least a portion of columns106) are then advanced through the esophagus and into the stomach along guidewire322. Once through the esophagus, distal and proximal capsules204,202separate, but remain flexibly coupled together by columns106and fluid tube210(note that tubes210,212are not shown inFIG. 12). The capsules202,204are also still aligned with each other by virtue of delivery tube structure150and guidewire322that remain extending through the entire device100. Once the entire device is within the stomach, support tube152is used to push the distal end of delivery tube structure150and distal capsule204through the pylorus into the proximal duodenum (seeFIG. 13). This may require the use of a dilator (not shown) to maintain the pylorus in its maximum diameter. Alternatively, a separate pusher rod (not shown) may be used to push the distal components of bypass device100into stomach30. It should be noted that it may not be necessary to encapsulate any components of device100in order to advance them through the patient's GI tract. In this case, these components will simply be advanced in their deflated configurations.

At this point, the surgeon will wait until capsules202,204dissolve (unless capsules202,204are not being used). It is expected that proximal capsule202will dissolve more rapidly, as it is designed to do so, and is subjected to a slightly more caustic environment within the stomach (alternatively, capsules202,204may comprise material that can be excreted naturally by the patient). Once the proximal components of bypass device100are freed from capsule202, a fluid, such as saline, is introduced through fluid tube212into the interior of inflatable member112until it is filled to the appropriate size (seeFIG. 14). After inflating gastric anchor102, and after distal capsule204has also dissolved, fluid is delivered through fluid tube210into the interior of inflatable member132of duodenal anchor104in a similar fashion.

Referring now toFIG. 15, once duodenal anchor104has been inflated into its operative configuration, sleeve108is advanced through the duodenum and into the jejunum to its final deployment position. Specifically, support tube152is used to push sleeve108and delivery structure150through the patient's small intestines. Once in final position, clamp158is released via the actuator device or handle outside of the patient (not shown) to disengage it from the distal end of sleeve108.

In an alternative embodiment, the surgeon will not wait until distal capsule204is dissolved before advancing sleeve108to its final deployment position in the small intestines. In this embodiment, once capsule204has been advanced through the pylorus into the proximal duodenum, gastric anchor102is inflated as discussed above. Capsule204is then advanced further into the duodenum until duodenal anchor104is forced out of the proximal opening of capsule204(anchor104will be prevented from further distal movement by gastric anchor102). Capsule204will then be advanced through the duodenum until the distal end of sleeve108reaches its final deployment position. Clamp158is then disengaged from sleeve108and removed from the patient as described above and capsule204will eventually dissolve.

As shown inFIG. 16, bypass device100should now be in its final position with gastric anchor102in pyloric antrum of stomach30and duodenal anchor104just distal to the pyloric sphincter20. Delivery structure150is removed from the patient and the distal end of fluid tubes210,212are cut with scissors or the like and removed. A gastroscope and/or fluoroscope (not shown) may be used to confirm the final placement of device100. Once device100is in place, guidewire322can be also removed from the patient.

A method for removing bypass device100according to the present invention will now be described. A gastroscope may be advanced through the esophagus and into the stomach30of patient in a suitable position for the surgeon to view the procedure. A sharp instrument (not shown) such as scissors or the like, is advanced through the patient's esophagus into stomach30. The sharp instrument is used to puncture gastric anchor102such that the fluid within the interior of membrane112exits into the stomach to deflate anchor102. Alternatively, a syringe or similar suction device (not shown) may be attached to the valve inlet120to withdraw the fluid from gastric anchor102.

Once deflated, gastric anchor is preferably positioned to the side of the antrum. A grasping or cutting instrument (not shown) is advanced through the esophagus to cut each of the pyloric columns106to detach gastric anchor102from the distal portion of device100. The last column106that is severed will be held by the grasping instrument to ensure that duodenal anchor104and sleeve108do not migrate in the distal direction after being detached from gastric anchor. At this point, a grasping tool or snare (not shown) is advanced into stomach30to grab gastric anchor102and gastric anchor102is then pulled through the esophagus and removed from the patient.

The sharp cutting instrument is then advanced through the pyloric sphincter20to puncture membrane132of duodenal anchor104to deflate duodenal anchor104. The grasping instrument may then be used to pull anchor104and sleeve108into stomach30. Once duodenal anchor104and sleeve108are within stomach30, they may be sliced up and removed or removed as a single unit. Subsequent to the removal of device100, a scope (not shown) can be used to determine if any tissue injury or insult that has been sustained by the implantation, use, or removal of device100. Provided no additional access to the stomach, pylorus, or duodenum is required, removal of the scope concludes the procedure.

Alternatively, the duodenal anchor104can be deflated without severing columns106and removing gastric anchor102. In this embodiment, the sharp instrument is advanced around gastric anchor102, through columns106and pylorus20to duodenal anchor104. Duodenal anchor is deflated and pulled into the stomach (along with sleeve108). The entire bypass device100may then be removed as a single unit, or it may be sliced up into smaller components to facilitate passage through the patient's esophagus.

FIG. 17illustrates one portion of an alternative embodiment of the gastric and duodenal anchors (for convenience only one of the anchors is shown inFIG. 17). In this embodiment, the anchors both include an outer wall housing a hollow interior designed for inflation as described above.FIG. 17illustrates a central portion400of the outer wall of the anchors. As shown, the anchors further include a valve402having an inlet404, a one-way valve member406, a fluid passage408and an expandable member410located within fluid passage408between the interior of the anchor and valve member406. Expandable member410preferably comprises a material designed to slowly absorb fluid upon, such as water or saline and expand with the absorbed fluid. In the preferred embodiment, expandable member410comprises a hydrogel material although other materials can be used that are well known in the art.

To inflate the anchor, fluid is delivered through inlet404such that it passes via fluid passage408past expandable member410and valve member406into the interior of the anchor. Valve member406is designed to prevent the fluid from flowing back through fluid passage408and inlet404. As additional protection from this event occurring, however, expandable member410will absorb fluid as the fluid fills the interior of the anchor and passes back through passage408to saturate expandable member410. Expandable member410is designed to expand when hydrated such that it completely blocks fluid passage408, thereby preventing any fluid flow in either direction through fluid passage. This not only provides additional protection from fluid leakage, but also prevents any unwanted fluid (such as stomach acid and the like) from passing into the interior of the anchor. Note that the expandable member410may also be located along the length of fluid tubes (210,212).

FIG. 18illustrates an alternative embodiment of a delivery system450of the present invention. In this embodiment, system450comprises an introducer tube451defining an elongate shaft452that has sufficient flexibility to extend through a patient's esophagus into the stomach (similar to the overtube described above). Shaft452has an open distal end454and an open proximal end (not shown as the entire shaft452of tube451is not shown inFIG. 18) and an internal lumen458designed as a working channel for passing instruments therethrough. Tube451further comprises a thin flexible bag or sleeve460comprising a suitable biocompatible material such as silicone or the like. Sleeve460houses a bypass device462such as one of the bypass devices described above. Sleeve460is preferably long enough to extend entirely through internal lumen458of shaft452to facilitate placement of sleeve460and device462in tube451(see below). In the preferred embodiment, sleeve460has open distal and proximal ends and is fastened to the proximal end of introducer tube451such that sleeve460remains within tube451when device462is propelled from tube451(see below). Sleeve460is also sized to allow it to fit within internal lumen458while still housing bypass device462in its collapsed configuration.

System450may optionally include a pusher or advancing member464including an elongate rod465with a proximal handle (not shown) and a distal pusher466designed to press against a proximal end of bypass device462when bypass device462is loaded within lumen458of tube451. In some embodiments, handle (not shown) can be used to collapse or expand pusher466(discussed below). Tube451further comprises a tapered distal end459around distal opening454to provide for atraumatic advancement through the esophagus.

In use, bypass device462is placed within sleeve460and sleeve460is loaded into the distal end portion of internal lumen458. In a preferred embodiment, the user extends the proximal end of sleeve460through the entire length of lumen458and pulls sleeve460proximally such that bypass device462is pulled into the distal end portion of lumen458. Once loaded, the device462is ready for implantation in the patient.

To implant the device, introducer tube451is extended through the patient's esophagus such that its proximal opening454is positioned within the stomach. Bypass device462is then propelled out of tube451into the stomach. This can be accomplished by passing advancing member464through proximal opening of introducer tube451and advancing it through lumen458until it propels bypass device462out of the distal opening454of tube451. Alternatively, other devices, such as a gastroscope, can be used to propel bypass device into the stomach.

In the preferred embodiment, sleeve460has open proximal and distal ends and is designed to remain within lumen458of tube451as bypass device462is advanced into the stomach. Thus, both sleeve462and tube451can be easily removed from the patient after device462has been deployed. In other embodiments, sleeve462passes into the stomach along with device462and is then detached or removed from device462. This can be accomplished by a variety of means, such as cutting the sleeve away from the device462. Alternatively, sleeve462may already include a cut-a-way portion that can be easily detached to open sleeve462and allow bypass device462to be removed. In yet another embodiment, sleeve462may comprise a dissolvable material that dissolves away within the stomach (similar to the capsules discussed above). Once it has been deployed into the stomach, bypass device462may be passed along a guidewire and deployed into its final position as discussed above.

In certain embodiments, introducer tube451is long enough to extend through the esophagus and stomach and through the pylorus into the duodenum of the patient. In these embodiments, tube451may optionally include a bend at its distal end portion to facilitate passage of the tube451through the natural bend in the human stomach between the esophagus and the pylorus. Alternatively, the delivery system may include a separate overtube having such a bend. In this embodiment, the separate overtube will be first inserted through the esophagus with a separate straight introducer therein (i.e., to maintain the overtube in a substantially straight configuration as it passes through the esophagus). Once the overtube has passed through the esophagus, the straight introducer is removed such that the overtube is allowed to bend within the stomach into its natural position. At that point, the flexible introducer tube451housing the bypass device is advanced through the overtube to the duodenum.

In use, once the distal opening of tube451resides in the duodenum, the distal end portions (i.e., the sleeve and the duodenal anchor) of the bypass device are propelled out of the distal opening of the introducer tube451and into the duodenum of the patient. The duodenal anchor is then inflated to prevent proximal movement of the distal end portions of the bypass device. The introducer tube451is then retracted through the pylorus and into the stomach. As this occurs, the gastric anchor will naturally be pulled out of the distal end of the introducer tube451from the counterforce of the inflated duodenal anchor against the distal surface of the pylorus. The gastric anchor may then be inflated within the stomach and the sleeve extended through the duodenum as described above.

In yet another alternative embodiment, the pusher device or advancing member is designed to perform multiple functions. Namely, the pusher device is sized and shaped to fit between the gastric and duodenal anchors within the introducer tube. In this capacity, the pusher device is used to push or propel duodenal anchor and sleeve out of the distal opening of the introducer tube into the duodenum. In addition, the pusher device will function to prevent the gastric anchor from being advanced through such distal opening when the distal opening is located within the duodenum. Once the distal opening of the introducer tube has been retracted through the pylorus into the stomach, the pusher device is designed to collapse and retract proximally through the middle of the gastric anchor. It can then be expanded again to propel the gastric anchor through the distal opening of the introducer tube and into the patient's stomach.

In one embodiment, the pusher device comprises an elongate rod coupled to a umbrella-shaped or claw-shaped proximal pushing device. The rod is sized to extend through the introducer tube and through the center of the gastric anchor. The proximal pushing device is sized to reside between the gastric and duodenal anchors. Distal advancement of the rod will cause the pusher device to propel the duodenal anchor through the distal opening of the introducer tube. The pusher device further comprises an actuator at the proximal end of the rod for collapsing the umbrella-shaped pushing device such that it can be retracted proximally through the center of the gastric anchor. The actuator can then be used to expand the pushing device such that further distal advancement of the rod will cause the pusher device to propel the gastric anchor through the distal opening in the introducer tube.

In yet another embodiment, an alternative method for implanting and removing the bypass devices of the present invention is now described. In this embodiment, the hollow sleeve includes one or more projections at its distal end designed to allow an endoscopic forceps, clips, clamp or similar device to attach to the projections. The projections can be loops, strings, protuberances or the like and are preferably made of the same material as the sleeve (such as silicone). The gastric and/or duodenal anchors may also include such projections for similar purposes.

In use, the bypass device is attached to an endoscopic scope by passing an endoscopic forceps or clamping device through the working channel of the scope and attaching the forceps to the projections on the distal end of the sleeve. The physician may then attach the remainder of the bypass device to the outer surface of the scope with a shroud, sleeve or other fastening device or just simply align the bypass device with the shaft of the scope. Alternatively, the scope may be advanced through the center of the two anchors of the bypass device and the sleeve such that the entire bypass device is positioned around the scope. The scope is advanced with the distal end of the sleeve through the patient's esophagus and stomach and through the pylorus into the duodenum. The remainder of the sleeve and the anchors of the bypass device are thereby pulled into the stomach alongside the scope.

Alternatively, the physician may attach the forceps to the projections on either the gastric or duodenal anchor and advance those portions of the implant through the esophagus first (i.e., passing the device into the stomach backwards). In this embodiment, the physician may then detach the forceps from the bypass device, remove the scope and attach the forceps to the distal end of the sleeve to advance the remainder of the sleeve into the patient's stomach. To avoid retraction of the anchors back through the esophagus, the gastric anchor may be fully or partially inflated after the forceps have been detached from the anchor and before withdrawing the scope through the esophagus.

After the anchors have been advanced into the stomach of the patient, the gastric anchor is preferably either partially or fully inflated as described above to prevent movement of the gastric anchor through the pylorus into the duodenum or through the lower esophageal sphincter into the esophagus. The physician then continues to advance the scope and the distal end of the sleeve through the duodenum to a position near the final target site within the patient's intestines (either in the distal duodenum or the proximal jejunum). At this point, the physician may detach the forceps from the distal end of the sleeve and withdraw the scope and forceps back into the patient's stomach.

To prevent the sleeve from “following” the scope proximally into the stomach, the physician will preferably temporarily fixate the sleeve within the duodenum. According to the present invention, one method of temporarily fixating the sleeve is to use a detachable clip (rather than the forceps described above) to grab the projection on the distal end of the sleeve. Once in position within the duodenum, the clip is opened and attached to mucosal tissue within the duodenum. The clip can then be deployed such that it is no longer attached to its shaft, but instead fastens the sleeve to the mucosal tissue on the inner wall of the intestines. This allows the scope and shaft of the clip device to be withdrawn while the sleeve is fixated within the duodenum.

In certain embodiments, multiple clips may be used to fasten the sleeve to the inner walls of the intestines. The clips may serve the purpose of creating an additional anchor for the device to prevent migration and to ensure that the sleeve remains patent during the period of time it is implanted within the patient. In addition, the clips will preferably be observable under fluoroscopy such that the physician can ensure that the sleeve has remained in place after implantation.

In another embodiment, the sleeve comprises one or more internal lumens extending down a portion of, or the entire length of, the sleeve. The internal lumens are preferably fluidly coupled to one of the flexible columns which are, in turn, fluidly coupled to a valve within the gastric anchor. In an exemplary embodiment, the sleeve will comprise 3 or 4 internal lumens spaced around its circumference. In use, a fluid is delivered through the gastric anchor and column and into the internal lumens of the sleeve. The fluid causes the sleeve to extend fully and inhibits proximal migration of the sleeve when the scope is retracted from the patient's duodenum. In addition, the fluid-filled lumens will ensure that the sleeve remains patent without any kinks or twists along its length.

Once the scope has been retracted from the duodenum, the duodenal anchor is advanced past the patient's pylorus into the proximal portion of the duodenum. Preferably, the scope is used to push the duodenal anchor through the pylorus. Alternatively, the forceps can be attached to one of the projections on either of the gastric or duodenal anchors to push and/or pull the duodenal anchor into position. The duodenal anchor is then inflated as described above.

In yet another alternative embodiment, the sleeve is “self-deploying” through the duodenum. In this embodiment, the sleeve is positioned within the proximal duodenum as described above and then allowed to “self-deploy” and advance through the duodenum into position. In one embodiment, the sleeve comprises internal fluid lumens as described above and the fluid is delivered into the lumens to force the sleeve to extend down the length of the duodenum. In another embodiment, the sleeve comprises a mass at its distal end (e.g., a thickened annular portion of the sleeve, one or more balls or projections attached to the distal end or the like). The mass will advance through the patient's intestines through natural peristalsis and pull the sleeve distally until it is fully extended. In yet another embodiment, the sleeve comprises a dissolvable portion at its distal end that occludes all or a portion of the distal end of the sleeve. In this embodiment, fluid is flushed through the sleeve and because its distal end is occluded causes the sleeve to extend distally. After the dissolvable portion dissolves within the intestines, the distal end of the sleeve is opened up to allow chyme to pass therethrough.

FIGS. 19 and 20illustrate an embodiment of an obesity device500according to the present invention. As shown, device500includes a gastric flow restrictor502coupled to a duodenal anchor504by a plurality of flexible silicone tethers or pyloric columns506and a hollow sleeve508coupled to the distal end of anchor504. Pyloric columns506are designed to extend through the pyloric sphincter20to allow both flow restrictor502and anchor504to move back and forth within the stomach30and duodenum50, respectively, with the natural peristalsis motion of the GI tract (seeFIG. 36). Pyloric columns506may be cylindrical or any other type of prismic shape and are preferably designed such that the distance between the distal end of flow restrictor510and the proximal end of anchor504is about 30 mm in the fully extended, but relaxed condition. Preferably, device500includes three or more pyloric columns506, which are attached to the distal end of flow restrictor502, through a button (not shown). The button is preferably comprised of a material having a greater rigidity than the rest of device500, and may either be co-molded into device500or assembled afterward as a separately manufactured component. The button is preferably configured similarly to a conventional button, being disc-shaped and having two or more bores (not shown). The button may be disposed within or adjacent to the distal-most flange. Alternatively, columns506may be glued to flow restrictor502or coupled to flow restrictor502during the molding process, as described above.

FIG. 21illustrates one embodiment of gastric flow restrictor502in an operative or expanded configuration. Flow restrictor502defines a longitudinal axis503and comprises one or more flanges510coupled to a central tube512extending substantially parallel to axis503. Central tube512preferably comprises a moderate durometer silicone approximately 20-50 mm in length and about 4-10 mm in outer diameter. Central tube512defines a lumen514along axis503for passage of a guidewire (not shown) during implantation and removal of obesity device500(discussed in detail below). In some embodiments, lumen514will have a inner diameter sized to also allow a scope (not shown) with a working channel to pass through. In other embodiments, lumen514will be smaller and sized only for passage of a guidewire.

Flow restrictor502further comprises one or more discs or flanges510extending outward from tube512and longitudinally spaced from each other. Flanges510may have identical or varying outer diameters, and due to their composition, may flex and bend during positioning of device500in stomach30. Flanges510preferably have a thickness of about 1-6 mm and comprise a lower durometer silicone than central tube512. In the preferred embodiment, obesity device500comprises a proximal flange that is larger in diameter than the distal flanges and effectively serves as the proximal surface of the central tube512. This provides flow restrictor502with a shape substantially corresponding to the anatomy of the distal portion of stomach30. All of the flanges510will have an outer diameter larger than the maximum diameter of the pyloric sphincter20. The proximal flange preferably has an outer diameter of about 40-60 mm, preferably about 50 mm, while the distal flanges preferably have an outer diameter of about 20-40 mm, preferably about 25 mm. Flanges510may also bend or flex due to the natural peristaltic action of stomach30during contact with surrounding stomach tissue. It should be understood by one of ordinary skill in the art that flanges510may be of any configuration that allows flanges510to be connected to one another in a generally parallel and stacked configuration while allowing device500to be positioned as described below.

As flanges510act to control or inhibit the flow of chyme between stomach30and duodenum50, the flow of gasses and other stomach fluids is similarly inhibited. Along with the normal peristaltic action of the surrounding tissue, such gasses may cause a buildup of pressure that may tend to force devices in a distal or proximal direction. Accordingly, flanges510may include one or more recesses, semicircular cutaway sections or radial slits (not shown) to aid in relieving such pressure between stomach30and duodenum50when device500is fully inserted by allowing such gasses to pass through the recesses. It is contemplated that the recesses or slits may be staggered circumferentially about flanges510without compromising the ability of the recesses to reduce pressure. These radial slits or cutaways may also assist in permitting the flow restrictor to be compressed into an “overtube” for endoscopic placement and/or permit food to pass around flanges510.

Flanges510preferably comprise one or more ribs516housed within a relatively flexible covering or frame518. Ribs516are preferably stiff enough to provide support for the flexible covering518in the operative position and will define a pivot point near central tube512to allow ribs516to pivot between the compact and operative positions. In an exemplary embodiment, ribs516and covering518are molded from a suitable biocompatible plastic, such as silicone. Ribs516have a durometer suitable for providing stiffness and support to the device, while frame518will have a softer durometer allowing flexibility and minimizing any adverse impact from tissue contact with the flanges.

Each flange510is movable between a first or operative position (FIGS. 20 and 21) wherein flanges510extend radially outward substantially perpendicular to longitudinal axis503and a second or compact position (not shown) wherein flanges510bend downward such that they form a small acute angle (almost parallel with) the longitudinal axis. In this respect, flow restrictor502operates in a similar manner as an umbrella. In the operative position, flanges510are designed to inhibit chyme flow from stomach30to pyloric sphincter20. In addition, since flanges510have a larger outer diameter than the inner diameter of pyloric sphincter20in its open position, they will prevent distal movement of flow restrictor502through pyloric sphincter20. In the compact position, flanges510can be bent downward to substantially reduce the diameter of flow restrictor502, allowing flow restrictor502to be advanced endoscopically through the patient's esophagus (not shown) and into stomach30, as discussed in more detail below.

As shown inFIG. 21, frame518of each of the flanges510has a substantially annular shape. However, it will be recognized that flanges510may have a variety of different shapes (e.g., square, triangular, diamond, rectangular, etc). In an alternative embodiment, the frames518comprise multiple projections550extending radially outward from central tube512, e.g., a fan blade shape (seeFIG. 24), a rose-petal shape and the like. As shown inFIG. 24, projections550of each flange510are preferably circumferentially spaced from the projections550of immediately adjacent flanges along the longitudinal axis503of flow restrictor502. For example, projections550of the top or proximal flange510are circumferentially spaced from each of the projections550in the next flange510below the top flange in the direction of the longitudinal axis. In this manner, when projections550are folded downward in the compact configuration, they will not interfere with each other, allowing the flow restrictor to conform to a smaller overall diameter in the compact configuration. Alternatively, flanges510may have a configuration wherein the projections fold downward in a spiral direction overlapping each other as they are folded into the compact configuration.

In any of these embodiments, flow restrictor502further comprises a locking mechanism for locking, biasing or otherwise securing ribs516in the operative or expanded position. This ensures that the flow restrictor will remain in the operative position while implanted in the patient. In one embodiment shown inFIG. 21, the locking mechanism comprises a plurality of leaf springs520coupled to ribs516at pivot points on central tube512. Leaf springs520bias ribs516into the operative position. Alternatively, ribs516may be designed to bias themselves into the operative configuration. This embodiment is illustrated inFIGS. 22 and 23. As shown, ribs516each comprise a rod552that extends radially outward in the operative configuration within the frame518of each flange510as discussed above. In addition, ribs516comprise a curved pivot bar554that extend around a circular ring556coupled to central tube512. Curved pivot bar554operates to bias the rod552of each rib516radially outward into the operative configuration.

Alternatively, the locking mechanism may comprise a separate device that engages the ribs and pivots them into the operative position.FIGS. 27 and 28illustrate such an embodiment. As shown, flow restrictor502comprises a plunger560that is extendable through lumen514(seeFIG. 22) of central tube512. Plunger560comprises a head564coupled to a main body562with multiple projections566extending radially outward from body562. In this embodiment, ribs516each define a rim568extending through tube512into lumen514. Projections566are designed to engage rims568of ribs516when plunger560is advanced into lumen514. Upon such engagement, plunger560will cause ribs516to pivot into the operative position as shown inFIG. 27. Ribs516and thereby flanges510will remain secured in the operative position so long as plunger560remains within lumen514of tube512. Plunger560can be locked into place within central opening by any suitable means. When the plunger560is removed, ribs516are free to pivot such that the user can bend flanges510into the compact configuration for insertion or removal into or from the patient.

FIGS. 25 and 26illustrate one preferred embodiment of anchor504and the proximal end of sleeve508in the expanded or operative configuration. As shown, anchor504comprises a locking member530and a tube532coupled to and extending distally from locking member530. Locking member530preferably has a harder durometer than tube532to provide for a secure anchor against the distal opening of the pyloric sphincter. This ensures that anchor504will remain in place within the duodenum50despite the natural peristalsis forces acting against anchor504. Tube532preferably has a funnel shape in the operative configuration such that its proximal opening534is larger than its distal opening535to generally correspond to the narrowing shape of the GI tract distal of the pyloric sphincter. Anchor504further comprises one or more bosses or ribs542extending from locking member530to the distal end535of tube532at the junction between tube532and sleeve508. Bosses542provide structural support for anchor504. Preferably, bosses542will have a slightly harder durometer than tube532and anchor508, but a softer durometer than locking member530. Bosses542will provide an elastic spring such that they will provide distal resistance against natural peristalsis forces pressing tube532towards the pyloric sphincter. In addition, bosses542provide a natural coupling point for pyloric columns506as shown inFIG. 20.

Locking member530is designed to move the proximal end of tube504between a first or compact position sized and shaped for advancement through the pyloric sphincter into the duodenum and a second or operative position sized and shaped for anchoring against the pyloric sphincter at the proximal end of the duodenum to prevent movement of anchor504through the pyloric sphincter. Locking member530is preferably designed to allow for movement from the compact position towards the operative position, while preventing the reverse movement back towards the compact position. This locks anchor504into the operative position after insertion into the patient. Locking member530may be biased towards the operative position, or it may be designed to require a force applied to locking member530to move it into the operative position.

In one embodiment (shown inFIGS. 25 and 26), locking member530comprises a ratchet having an annular sliding bar536coupled to the proximal end of tube532. Bar536has a spiral configuration and is designed for circular displacement over itself. Bar536includes teeth538that engage a catch (not shown) within a hollow section540of bar536to allow for movement of bar536in the clockwise direction, but prevent reverse movement in the counterclockwise direction. Thus, as bar536rotates clockwise, its outer diameter increases to increase the outer diameter of proximal opening534of tube532. Bar536can be expanded outward with a force applied to its inner surface (e.g., from a separate balloon designed for such purpose as discussed in detail below). Hollow section540of bar536further comprises a tab541that can be removed to release bar536from teeth538and allow for compression of anchor504during removal of the device (discussed below).

In an alternative embodiment, the locking member comprises a bar member that is movable between a substantially spiral configuration to a substantially circular configuration. In exemplary embodiments, the locking member will have multiple operative positions such that the physician can appropriately size the anchor depending on the anatomy of the individual patient.

FIGS. 29 and 30illustrate an alternative embodiment of an obesity device600that is inflated into the operative configuration. As shown, obesity device600comprises a flow restrictor602coupled to an anchor604with a plurality of pyloric columns606, and a hollow sleeve608coupled to anchor604(only the proximal portion of sleeve608is shown inFIG. 29). In this embodiment, flow restrictor602comprises an outer collapsible shell610surrounding a hollow interior section612. Collapsible shell610is movable between the inflated or operative configuration shown inFIG. 29to a deflated or collapsed configuration (not shown) for placement and removal from the patient. Collapsible shell610has a roughly cylindrical inner core portion614with proximal and distal flanges616,618. Shell610preferably comprises a moderate durometer silicon with a wall thickness of about 0.5-4.0 mm, preferably between about 1-3 mm. Flanges616,618are rounded at the circumference to provide atraumatic contact with tissue and are spaced from each other by about 10 to 40 mm, preferably between about 20 to 25 mm. Proximal flange616preferably has an outer diameter of about 40-60 mm and distal flange preferably has an outer diameter of about 25-35 mm. Flanges616,618preferably each comprise one or more semicircular cutaways626to permit food passage and retrograde fluid pressure relief.

Interior section612is fluidly coupled to a tube620having an opening (not shown) at the proximal surface of proximal flange616for inflating interior section612into the operative configuration shown inFIG. 29. Tube620comprises a one-way valve (not shown), such as an umbrella valve, to ensure that fluid delivered into interior section612will not pass out of tube620after flow restrictor602has been inflated. Core portion614has an outer diameter of approximately 3-15 mm, preferably between about 4 to 6 mm, and a length of about 25-35 mm when interior section612is fully inflated. Flow restrictor602preferably includes a pair of protuberances638at its proximal end that can be grabbed by a simple grasping instrument to pull/manipulate the device as required during implantation/removal.

As shown inFIG. 30, a hollow tube622extends through the central axis of flow restrictor602. Tube622preferably comprises a hard plastic wall with an interior diameter of about 2-4 mm. Tube622provides stiffness to flow restrictor602as well as providing a lumen for guide wire and instrument access through flow restrictor602to the distal components of obesity device600(discussed below). In addition, a fluid lumen624extends through flow restrictor602to allow for fluid passage through one of the fluid columns606to inflate anchor604as discussed below. Fluid lumen624will also comprise a one-way valve (not shown) to ensure that anchor604remains inflated during operation of the device. Alternatively, interior612of flow restrictor602may be fluidly coupled to the interior of anchor604or a separate exterior fluid line (not shown) may be used to deliver fluid into anchor604(discussed in more detail below with respect to the embodiment shown inFIGS. 31-32).

In this embodiment, anchor604comprises an inflatable annular tube630coupled to an internal support ring632and a funnel634. Inflatable tube630is movable between a collapsed position for advancement through the pyloric sphincter and an expanded or inflated position wherein tube630has an outer diameter that is greater than the maximum diameter of the pyloric sphincter in its open position to prevent proximal migration of anchor604through the pyloric sphincter. Internal support ring632has a diameter slightly less than the maximum diameter of the pyloric sphincter and comprises a harder durometer silicone to provide stiffness and support to tube630. In particular, support ring632ensures that tube630maintains a substantially circular shape as it encounters intestinal forces such that the tube630cannot be squeezed back through pyloric sphincter by the peristalsis forces within the small intestine.

Inflatable tube630is preferably fluidly coupled to one or more of the bosses636extending from proximal to distal ends of anchor funnel634. Bosses636, in turn, are fluidly coupled to one or more of the pyloric columns606, i.e., through internal lumens in one or more of the bosses636and columns606. Bosses636preferably have some elasticity and will provide stiffness to the overall funnel shape such that anchor604cannot be twisted into a smaller configuration for proximal migration through the pyloric sphincter. The boss636that includes a fluid lumen is fluidly coupled to internal lumen624in flow restrictor602. Internal lumen624preferably has an inlet (not shown) at the proximal end of flow restrictor602allowing the physician to deliver fluid to lumen624and thus inflatable tube630. In an exemplary embodiment, the one-way valve will be positioned at the proximal end of internal lumen624rather than within inflatable tube610as discussed above. In this embodiment, the one-way valve will preferably have a mechanism that will allow for opening of the value and removal of fluid from device600during removal of device600from the patient (discussed in detail below).

In addition to, or as an alternative to, the one-way valve, a curable fluid, such as silicone, may be injected into the fluid pathway after the saline. The curable fluid will cure and harden, thereby preventing any fluid egress from the interior of tube630. In another embodiment, the inflatable members of the flow restrictor and/or the anchor may comprise a material that self-seals when punctured with a very sharp small instrument such as a syringe. In this embodiment, the inflatable members of the obesity device may simply be inflated with a syringe and then self-sealed by the material to prevent fluid egress.

Referring now toFIGS. 31 and 32, another preferred embodiment of a flow restrictor602is illustrated. Similar to the previous embodiment, flow restrictor602comprises an inflatable outer membrane662surrounding a hollow interior664such that membrane662can be inserted into the patient's stomach in a deflated or collapsed configuration and then inflated into the operative configuration. In this embodiment, membrane662comprises a relative thin flexible material, such as silicone, preferably having a wall diameter of about 0.1 to 1 mm thick. Flow restrictor602further comprises proximal and distal sheets666,668that may be molded with, or glued to, membrane662as discussed. Alternatively, sheets666,668and membrane662may be constructed as a single piece such that membrane662constitutes the entire outer wall of the structure. Proximal and distal sheets666,668preferably have a slightly greater thickness (e.g., preferably between about 0.5 mm to 2.0 mm) and stiffness than membrane662to provide flow restrictor602with support and to hold its annular shape in the operative configuration.

Flow restrictor602further comprises one or more ribs or bosses670and one or more support members672extending along membrane662from proximal sheet666to distal sheet668. Bosses670and support members672preferably comprise a slightly thicker silicone material (i.e., preferably about 1.0 mm to 2.0 mm thick) and provide further support to the overall structure of flow restrictor602. In an exemplary embodiment, support members672have an arcuate shape and form cut-a-ways or recesses674in the otherwise conical shape of flow restrictor602. Recesses674provide paths for passage of chyme in stomach30past flow restrictor602to the pyloric sphincter and for passage of gases and/or fluids between the stomach and the duodenum. In the exemplary embodiment, bosses670are formed on the outside surface of membrane662and support members672are formed within the inner surface of membrane662. However, it will be recognized by those skilled in the art that a variety of different configurations can be employed to provide structure to flow restrictor602in the inflated configuration.

Flow restrictor602further includes a central tube676having an inner lumen678extending along its longitudinal axis and a one-way valve680with an opening in distal sheet666. Central tube676preferably has a wall thickness of about 0.1 mm to 1 mm and an inner diameter of between about 2 mm to 4 mm. Central tube676provides additional structural support for flow restrictor602and also provides a lumen for passage of a guidewire and/or other instruments, such as a gastroscope. One-way valve680is configured for coupling to a fluid tube (not shown) for delivering a fluid, such as saline, to the interior664of membrane662for inflation of flow restrictor602.

In reference toFIGS. 33-39, a method of implanting and removing an obesity device800(similar to one of, or a combination of, the embodiments shown inFIGS. 19-32according to the present invention will now be described. While the description of this method will be specifically directed to the embodiments illustrated above, it will be understood by those skilled in the art that this method (or similar methods) can be used to implant and remove all of the embodiments of the present invention, including embodiments or designs that may not be specifically described or illustrated herein.

Device800enters and exits the patient through esophagus702and is ultimately positioned in its operative state, wherein pyloric columns606(shown inFIG. 29) extend through pyloric sphincter20(e.g., seeFIG. 36). In certain embodiments, flow restrictor602(FIG. 29) and anchor604(FIG. 29) are separately encapsulated for implantation such that each may be independently released. Ideally, anchor604is released first such that anchor604and sleeve608(FIG. 29) are advanced as a single uninflated structure into the duodenum, coupled to flow restrictor602by columns606. The flow restrictor602is then inflated following the proper positioning of anchor604and sleeve608. In other embodiments, the flow restrictor and anchor are not encapsulated and are simply advanced through the esophagus or the overtube in their deflated configurations.

Initially, a gastroscope706is lubricated, inserted into patient's mouth707, and fed through esophagus702and the gastroesophageal (“GE”) junction into stomach20, as shown inFIG. 33. Gastroscope706is preferably approximately 9.8 millimeters in length, and preferably has approximately a 2.8 millimeter working channel and suitable viewing and recording equipment, for example. It will be understood that tools and components that are described as being passed through or inserted into gastroscope706are passed through or inserted into its working channel. A lubricant such as Surgilube or equivalent may be provided as needed to lubricate the obesity device and/or any of the associated surgical equipment.

Gastroscope706should ultimately be positioned such that its distal end708is adjacent to pyloric sphincter20. Preferably, a guidewire722is hydrated and inserted through gastroscope706. Guidewire722is passed through pyloric sphincter20, which may be aided by manipulation of gastroscope706. It may also be beneficial to pass a distal end708of gastroscope706through pyloric sphincter20in order to maneuver guidewire722through same. There should preferably be at least about 30-40 centimeters of the length of guidewire722passed distally through pyloric sphincter20and into small intestine40so that any further movement of guidewire722during the insertion procedure does not result in the accidental removal of the distal end of guidewire722to a position proximal of pyloric sphincter20. Of course, the length of guidewire722that should preferably be passed distally through pyloric sphincter20may vary according to different patients and/or procedures and may be less or more than 30-40 centimeters. After guidewire722is appropriately positioned, gastroscope706is removed from the patient.

Referring now toFIG. 34, an overtube730is positioned over the guidewire722and advanced through the esophagus and into the patient's stomach. Overtube730typically has an inner diameter of approximately 16 mm. Obesity device800is lubricated and positioned over the guidewire722outside of the patient. Once overtube730is positioned within stomach30, a small steerable scope (not shown) is advanced through overtube730into stomach30through the pylorus and into the proximal portion of the duodenum. The scope is used to confirm the tissue of the stomach, pylorus and duodenum are robust and show not overt signs that they will not tolerate the device. In an exemplary embodiment, a small tube (not shown) may be inserted into the pylorus. The tube includes a distal inner tube-shaped balloon (not shown) that expands to a known diameter with a known volume of saline. In conjunction with the scope images and other prior imaging data, this instrument is used to determine the appropriate size of obesity device800to be used, particularly the appropriate size of anchor604.

Once the appropriate size obesity device800is selected, a pusher rod732is used to push obesity device800into stomach30. In the exemplary embodiment, flow restrictor602is encapsulated within a proximal capsule734and both anchor604and sleeve608are preferably encapsulated within a distal capsule736to help advance device800through overtube730. It should be noted that it may not be necessary to encapsulate flow restrictor602and anchor604(FIG. 29) in order to advance them through overtube730. In this case, these components will simply be advanced through overtube730in their deflated configurations.

Referring now toFIG. 35, distal capsule736is removed and anchor604and sleeve608are advanced with pusher rod732(not shown inFIG. 35) through the pylorus and into the proximal portion of the duodenum. This may require the use of a dilator (not shown) to maintain the pylorus in its maximum diameter. Once positioned properly, a fluid, such as saline or another appropriate fluid is injected through an external tube (not shown) and one-way valve into the expandable membrane to inflate the membrane to its expanded or operative configuration. The external tube would then be cut by a pair of scissors or other such instrument that can be advanced through the working channel of overtube730. Alternatively, the fluid may be delivered through a syringe directly into the membrane or through an internal tube within the flow restrictor that is coupled to the interior of the membrane as described previously.

Once the anchor604has been inflated into its operative configuration, knob750at the distal end of sleeve608is grasped by a suitable grasping instrument and advanced downwardly through the duodenum and into the jejunum. When sleeve608has reached its maximum length, perforation752is torn and sleeve608is fully deployed. Knob750and perforation752can then be removed from the patient. Alternatively, sleeve608may be positioned either before anchor604has been inflated or after flow restrictor has been inflated as described below.

Referring now toFIG. 36, proximal capsule734(shown inFIG. 35) is then disengaged from flow restrictor602and removed from the patient. A fluid, such as saline, is injected through inlet680(seeFIG. 31) into the interior portion664of flow restrictor602to inflate flow restrictor602into its operative configuration. Obesity device800should now be in its final position with flow restrictor602in pyloric antrum740of stomach30and expandable membrane642of anchor604just distal to the pyloric sphincter20. A gastroscope and/or fluoroscope (not shown) may be used to confirm the final placement of device800. Once device800is in place, guidewire722and overtube730can be removed from the patient.

Referring now toFIGS. 37-39, a method for removing obesity device800according to the present invention will now be described. As shown inFIG. 29, overtube730is advanced through the esophagus and into position within the stomach30of patient and a gastroscope (not shown) is deployed through overtube730in a suitable position for the surgeon to view the procedure. A sharp instrument760, such as scissors or the like, is advanced through overtube730into stomach30. Sharp instrument760is used to puncture flow restrictor602such that the fluid within interior portion664of flow restrictor602exits interior portion664into the stomach to deflate flow restrictor602. Alternatively, a syringe or similar suction device (not shown) may be attached to inlet680to withdraw the fluid from flow restrictor602.

Referring now toFIG. 38, flow restrictor602is preferably positioned to the side of antrum740. A grasping or cutting instrument762is advanced through overtube730to cut each of the pyloric columns606to detach flow restrictor602from the distal portion of device800. The last column606that is severed will be held by grasping instrument762to ensure that anchor604and sleeve608do not migrate in the distal direction after being detached from flow restrictor602. At this point, a grasping tool or snare (not shown) is advanced into stomach30to grab one or both of protuberances638on the proximal surface of flow restrictor602. Flow restrictor602is then pulled through overtube730and removed from the patient.

Referring now toFIG. 39, a grasping instrument764is then advanced through the pyloric sphincter20to grasp a ball element attached to wire embedded in the inner membrane of the ring-inner tube structure. Grasping instrument764is pulled to cause the fluid within membrane642to exit membrane642and deflate anchor604. Grasping instrument764may then be used to pull anchor604and sleeve608into stomach30. In alternative embodiments, membrane642is fluidly coupled to a lumen (not shown) within flow restrictor602through one or more of the boss(es)635and column(s)606. In these embodiments, cutting of the column(s)606will automatically deflate membrane642.

Once anchor604and sleeve608are within stomach30, they may be sliced up and removed or removed as a single unit. Subsequent to the removal of obesity device800, a scope (not shown) can be used to determine if any tissue injury or insult that has been sustained by the implantation, use, or removal of device800. Provided no additional access to the stomach, pylorus, or duodenum is required, removal of the scope and overtube730conclude the procedure.