Obesity is associated with a wide variety of health problems, including Type 2 diabetes, hypertension, coronary artery disease, hypercholesteremia, sleep apnea, and pulmonary hypertension. It also exerts an enormous strain on the body that affects the organs, the nervous system, and the circulatory systems. Obesity rates have been rising for years in the United States, causing corresponding increases in healthcare expenditures.
Curing obesity has so far vexed the best efforts of medical science. Dieting is not an adequate long-term solution for most people, especially those with body-mass indexes of over 30. Stomach stapling, or gastroplasty, reduces the size of the stomach, leading to reduced appetite and weight loss, but eventually the stomach stretches. Roux-en-Y gastric bypass reduces the size of the stomach and the length of the intestine, and leads to both weight loss and alleviation of the Type 2 diabetes common to obese patients. Although gastric bypass appears to provide a more permanent solution than gastroplasty, complication rates associated with gastric bypass are between 2% and 6%, with mortality rates of about 0.5-1.5%.
Endoscopically delivered gastrointestinal implants, such as those described in commonly assigned U.S. Pat. Nos. 7,025,791 and 7,608,114 to Levine et al., incorporated herein by reference in their entireties, provide the benefits of gastric bypass without the hazards of surgery. For example, an implant may include thin-walled, floppy sleeves that are secured in the stomach or intestine with a collapsible anchor. The sleeve extends into the intestine and channels partially digested food, or chyme, from the stomach through the intestine in a manner that may cause weight loss and improve diabetes symptoms. The sleeve and anchor can be removed endoscopically when treatment is over or if the patient desires.
A gastrointestinal implant device may include a collapsible stomach anchor and a collapsible duodenal anchor coupled to each other by a radially collapsible coupling member, where the device can be secured across the pylorus. The stomach and duodenal anchors have vertices that define first and second planes, respectively, that are maintained at a substantially constant angle with respect to each other by the coupling member. For example, the coupling member may hold the first and second planes substantially parallel to each other. The example implant device may include an unsupported, thin-walled sleeve that is configured for deployment within the intestine and coupled to the stomach anchor, duodenal anchor, and/or coupling member. The stomach anchor, duodenal anchor, and/or coupling member may also be at least partially covered in a fluoropolymer such that they form a seal that channels chyme (partially digested food) from the stomach through the sleeve.
An example implant device and its components can vary in size depending on whether or not the device is in a relaxed state or a compressed state. When in a relaxed state, an example stomach anchor defines a circle whose diameter is greater than about 60 millimeters. Similarly, a relaxed duodenal anchor can define a circle whose diameter is greater than about 40 millimeters. The diameter of the coupling member may be within a range of from about 10 millimeters to about 25 millimeters, and the coupling member may be within a range of about 30 millimeters to about 60 millimeters in length, e.g., about 40 millimeters long. The example device may be made of single wire, or, alternatively, the stomach anchor, duodenal anchor, and coupling member can be formed of different wires, such as nickel-titanium (nitinol) wire with a diameter of about 0.016 inches to about 0.025 inches.
The stomach and duodenal anchors may comprise, respectively, stomach and duodenal prongs that extend outwards from the vertices to secure the implant device across the pylorus. When in a relaxed state, the stomach prongs form a first angle from the first plane, and the duodenal prongs form a second angle with the second plane. Each anchor may include two to six prongs, each of which may be between about 10 millimeters long and about 40 millimeters long; typically, though not necessarily, the stomach prongs are longer than the duodenal prongs. The stomach and duodenal prongs can be arranged in first and second star-shaped configurations, respectively, when viewed axially, and may be arranged so that the first and second star-shaped configurations are arranged in an alternating fashion.
Each prong may include a crown adapted to engage tissue in the gastrointestinal tract, such as in the lower stomach, the pylorus, or the duodenum. The crowns of the stomach and duodenal anchors can define first and second circles whose diameters are greater than about 60 millimeters and about 40 millimeters, respectively, in a relaxed state. Each crown can have a radius of curvature of about 0.1 inch to about 0.4 inch.
Gastrointestinal implant devices can be deployed in the gastrointestinal tract with a delivery device that maintains the stomach and duodenal anchors in respective collapsed states during insertion. The anchors can be configured to self-expand to respective relaxed states when released from the delivery device into the gastrointestinal tract. The stomach and duodenal anchors may expand from their respective collapsed states to their respective relaxed states in a variety of different ways. For example, at least one of the anchors may “spring open”—that is, it may form an acute angle with the coupling member in its respective collapsed state and an angle greater than the acute angle with the coupling member in its respective relaxed state. Alternatively, at least one of the anchors may “spring shut” from an obtuse angle formed with the coupling member in its respective collapsed state to an angle smaller than the obtuse angle in its respective relaxed state.
The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.
A description of example embodiments of the invention follows.
Transpyloric anchors are disclosed as alternatives to anchors provided in implants disclosed in U.S. Pat. No. 7,025,791; U.S. Pat. No. 7,608,114; U.S. Pat. No. 7,476,256; U.S. patent application Ser. No. 11/330,705; and U.S. patent application Ser. No. 11/827,674, all of which are incorporated herein by reference in their entireties.
The distal member 330 is also a single wire formed into a star configuration of duodenal prongs 332, each of which has a crown 334. The number of duodenal prongs 332, the number of crowns 334, and rotational orientation of the distal member 330 with respect to the proximal member 310 depends on the wire strength and the location of the seal. For example, the proximal and distal members 310, 330 may be aligned in phase with each other or slightly out of phase with each other such that they press against opposite sides of the tissue separating the proximal and distal members 310, 330. Arranging the proximal and distal members 310, 330 in phase or slightly out of phase with each other improves resistance to forces exerted along the longitudinal axis of the intestine, but may cause erosion of the tissue between the stomach and duodenal prongs 312, 332. Alternatively, the proximal and distal members 310, 330 may be aligned out of phase with each other, as shown in
The stomach and duodenal prongs 312, 332 flare outwards from the proximal and distal members 310, 330 and trace out circular envelopes when viewed along the longitudinal axis of the anchor 300. The envelopes have diameters that are large enough to prevent the anchor 300 from being pulled through the pylorus in either direction. For example, when relaxed, the crowns 314 of the stomach prongs 312 may trace a circle with a diameter greater than about 50 millimeters, or, more preferably, greater than about 60 millimeters, to prevent the anchor 300 from being pulled into the intestine. Similarly, the crowns 334 of the duodenal prongs 332, when in a relaxed state, may trace a circle with a diameter of greater than about 40 millimeters to prevent the anchor from being pulled through the pylorus into the stomach. Each stomach and duodenal prong 312, 332 is preferably between about 10 and about 40 millimeters long, and, more preferably, between about 15 and 30 millimeters long. The stomach and duodenal prongs 312, 332 may bend under loading, changing the shape and size of the envelope traced by the stomach and duodenal prongs 312, 332.
The connector 320 maintains a fixed angle between the proximal anchor 310 and the distal anchor 330. The proximal anchor 310 defines a plane 318 at the connection between the coupling member 320 and the proximal anchor 310. The connection between the distal anchor 330 and the coupling member 320 defines a second plane 338. The coupling member 320 should have sufficient stiffness linearly to maintain a fixed angle between plane 318 and plane 338. Preferably, as shown in
The connector 320 is preferably able to collapse easily and sufficiently enough for the pylorus to function. The radial force required to collapse the connector 320 diameter by 50% should be preferably no greater than about 0.5 lbs. Thus, the connector 320 may be rigid in the longitudinal direction, but radially collapsible. Here, the connector 320 is a single wire that connects the proximal and distal members 310, 330. Loops 322 in the connector 320 hold the inner points of the members 310, 330—that is, the vertices, or junctions 316, 336 between adjacent prongs 312, 332. The wire segments 324 connecting the loops 322 are woven together, allowing the connector 320 to flex without comprising the connection between the proximal and distal members 310, 330.
When the transpyloric anchor 300 is in a relaxed state, the stomach and duodenal prongs 312, 332 flare outwards from the planes 318, 338 defined by the vertices 316, 336 at either end of the coupling member 320. Depending on the configuration, the prongs 312, 332 may form acute or obtuse angles with the long axis of the connector 320. In this example, both the stomach prongs 312 and the duodenal prongs 332 form acute angles with the coupling member 320—i.e., the crowns 314, 334 fold towards the center of the coupling member 320 when uncompressed. Alternatively, the crowns 314, 334 may point away from the coupling member 320 when uncompressed; in some cases, one set of prongs 312, 332 may form an obtuse angle with the coupling member 320 and the other set of prongs 312, 332 may form an acute angle with the coupling member 320.
In general, any transpyloric anchor may be coupled to a thin-walled sleeve that is configured to extend into the intestine. The sleeve may be made of a fluoropolymer, such as expanded polytetrafluoroethylene (ePTFE) coated or impregnated with fluorinated ethylene polyethylene (FEP), or any other suitable material, and the transpyloric anchor may be coated, covered, or wrapped in the same material used to form the sleeve. A typical sleeve is floppy and conformable to the wall of the intestine when deployed. It also has a wall thickness of less than about 0.0005 inch to about 0.001 inch and a coefficient of friction of about 0.2 or less. The sleeve and anchor covering can be a single, integrally formed piece. They can also be separate pieces, depending on whether the transpyloric anchor is partially or wholly uncovered, as long as the transpyloric anchor forms a sufficiently good seal between the sleeve and the stomach, pylorus, and/or intestine.
Transpyloric anchors may be inserted endoscopically in a variety of undeployed configurations. Once inserted, a transpyloric anchor may self-expand across the pylorus, as shown in
While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention.
This application claims the benefit of U.S. Provisional Application No. 61/217,318, filed on May 29, 2009. The entire teachings of the above application are incorporated herein by reference.
Number | Date | Country | |
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61217318 | May 2009 | US |