This invention relates to medical devices, and more particularly to obesity treatment devices that can be placed in the stomach of a patient to reduce the size of the stomach reservoir.
It is well known that obesity is a very difficult condition to treat. Methods of treatment are varied, and include drugs, behavior therapy, and physical exercise, or often a combinational approach involving two or more of these methods. Unfortunately, results are seldom long term, with many patients eventually returning to their original weight over time. For that reason, obesity, particularly morbid obesity, is often considered an incurable condition. More invasive approaches have been available which have yielded good results in many patients. These include surgical options such as bypass operations or gastroplasty. However, these procedures carry high risks, and are therefore not appropriate for most patients.
In the early 1980s, physicians began to experiment with the placement of intragastric balloons to reduce the size of the stomach reservoir, and consequently its capacity for food. Once deployed in the stomach, the balloon helps to trigger a sensation of fullness and a decreased feeling of hunger. These balloons are typically spherical or pear-shaped, generally range in size from 200-500 ml or more, are made of an elastomer such as silicone, polyurethane, or latex, and are filled with air, water, or saline. While some studies demonstrated modest weight loss, the effects of these balloons often diminished after four to twelve weeks, possibly due to the gradual distension of the stomach or the fact that the body adjusted to the presence of the balloon. Other balloons include a tube exiting the nasal passage that allows the balloon to be periodically deflated and re-insufflated to better simulate normal food intake. However, the disadvantages of having a inflation tube exiting the nose are obvious.
Unrelated to the above-discussed methods for treating obesity, it has been observed that the ingestion of certain indigestible matter, such as fibers, hair, fuzzy materials, etc., can collect in the stomach over time, and eventually form a mass called a bezoar. In some patients, particularly children and the mentally handicapped, bezoars often result from the ingestion of plastic or synthetic materials. In many cases, bezoars can cause indigestion, stomach upset, or vomiting, especially if allowed to grow sufficiently large. It has also been documented that certain individuals having bezoars are subject to weight loss, presumably due to the decrease in the size of the stomach reservoir. Although bezoars may be removed endoscopically, especially in conjunction with a device known as a bezotome or bezotriptor, they, particularly larger ones, often require surgery.
What is needed is an intragastric member that provides the potential weight loss benefits of a bezoar or intragastric balloon while minimizing complications. Ideally, such a-device should be well-tolerated by the patient, effective over a long period of time, sizable for individual anatomies, and easy to place and retrieve.
The present invention provides an intragastric device for the treatment of obesity in a mammal which acts as an artificial bezoar and is well-tolerated by the stomach. The intragastric device is effective in achieving weight loss over a several month period in animals, while also being easy to place and retrieve. At the same time, the device takes up a smaller volume within the stomach than existing intragastric members such as balloons, with no reduction in efficacy. The intragastric device generally comprises a digestive-resistant mesh material that is operable between a first configuration and a second configuration. The first configuration is sufficiently small to permit introduction of the digestive-resistant mesh material into a gastric lumen of the mammal. The second configuration is sufficiently large to prevent the digestive-resistant mesh material from passing through the mammal's pylorus, thereby permitting the mesh material to act as an artificial bezoar.
According to more detailed aspects of the present invention, the mesh material is elongated in the first configuration and is collected together in the second configuration. The mesh material includes first and second ends, and in the second configuration the first end is positioned near the second end and the mesh material is bundled between the first and second ends. The mesh material is at least partially contained within a delivery sheath in the first configuration, and is delivered through the sheath and collected to form the second configuration. The delivery sheath is sized to be passed through a gastric lumen such as the esophagus.
Another embodiment of intragastric device comprises a yoke and at least one elongated member of digestive-resistant mesh material. The mesh member has a first end and a second end positioned near each other with the mesh material bundled therebetween. The yoke is preferably a thread such as a polypropylene suture, and may be connected to the first and second ends in various manners. Preferably, the thread is tied to the first end of the mesh member and a stopper is used to engage the thread proximate the second end of the strip. The thread is woven through openings in the mesh member, and preferably the mesh member comprises a tube which is temporarily flattened to weave the thread therethrough. The thread may be woven along a centerline of the mesh member or may alternate between opposing sides of the centerline. Likewise, the tube may be folded lengthwise and the thread woven through openings of the mesh material to maintain the folded configuration.
The present invention also provides a method of treating obesity in animals. The method generally includes the introduction of a delivery sheath into a gastric lumen of the mammal, the delivery sheath defining a delivery lumen. A member of digestive-resistant mesh material is introduced into the delivery lumen. The mesh member has a distal end, a proximal end, and a yoke that is connected to the distal end of the mesh member. A pusher is introduced into the delivery lumen and includes a plurality of coupling pawls. The coupling pawls are pointed distally to move the mesh member distally upon distal translation of the pusher. The pusher is reciprocated distally and proximally within the delivery lumen to deliver the mesh member into a stomach of the mammal. The mesh member is bunched into a collected configuration sized to prevent the mesh member from passing through the mammal's pylorus. The yoke is connected to proximal end of the mesh member to maintain the collected configuration thereof.
A delivery device is also provided in accordance with the teachings of the present invention. The delivery device generally comprises a delivery sheath and a pusher. The delivery sheath is sized for introduction into the gastric lumen, and the delivery sheath defines a delivery lumen. The pusher is sized for introduction into the delivery lumen and includes pawls projecting distally. The pawls engage the mesh material when the pusher is moved distally relative to the delivery sheath, and disengage the mesh material when the pusher is moved proximally relative to the delivery sheath.
According to more detailed aspects of the delivery device, the pawls project distally to a free end structured to pass through an opening of the mesh material. The pawls may take many configurations, including being axially spaced and/or circumferentially spaced. Preferably the pawls are formed at a distal end of the pusher. Similarly, the delivery sheath may define retention pawls projecting radially into the delivery lumen. The retention pawls project distally to engage the mesh material when the pusher is moved proximally relative to the delivery sheath. In this manner, the pusher may be reciprocated to advance the mesh member into the stomach while the retention pawls resist proximal movement of the mesh. material. The pusher may take the form of a tube, and the tube may include V-shaped cuts formed therein to define a wedge of tube material that is formed to project radially outwardly and form the pawls. The pusher may also comprise a semi-annular member having a first longitudinal edge and a second longitudinal edge which define the pawls in those edges. The pusher may also take the form of a tube defining a push lumen, and further include a control member positioned inside the pusher lumen and having a plurality of wires projecting distally to form the pawls. The control member and plurality of wires are translatable within the push lumen and operable between a first expanded state for engaging the mesh member and a second withdrawn state for disengaging the mesh member. The plurality of wires are biased radially outwardly towards the first expanded state. In this latter construction, engagement and disengagement of the mesh material may be controlled through the relative translation of the control member and push tube, thereby providing greater control over the reciprocation of the pusher and advancement of the mesh member.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:
Turning now to the figures,
The intragastric device 20 comprises one or more digestive-resistant or indigestible members 22. As used herein, the terms digestive-resistant and indigestible are intended to mean that the material used is not subject to the degrative effects of stomach acid and enzymes, or the general environment found within the gastric system over an extended period of time, therefore allowing the device to remain intact for the intended life of the device. This does not necessarily mean that the material cannot be degraded over time; however, one skilled in medical arts and gastrointestinal devices would readily appreciate the range of material that would be suitable for use as a long-term intragastric member.
Many well-known plastics have suitable properties for forming the indigestible member 22, including selected polyesters, polyurethanes, polyethylenes, polytetrafluoroethylene (PTFE), polyamides, silicone, or other possible materials. Mammalian hair has been found to form natural bezoars, and thus, is also a possible material. However, some materials, such as certain polyamides, have been found to expand over time, which can be an undesirable property. Most other natural materials are generally much less resistant to acids and enzymes, and would therefore typically require treatment or combination with resistant materials to function long term, unless a shorter-term placement is intended or desired.
The indigestible member 22 is also constructed from a mesh or mesh material, and may take many forms including strips, tubes, and sheets, although many other forms will be readily apparent to those skilled in the art. A tubular mesh member 22 has been depicted in the figures and will be used to describe the invention, although any of these forms may be readily employed. Notably, it is believed that the use of a mesh material for the indigestible member 22 improves patient tolerance of the intragastric device 20. More particularly, the pliability and feel of the mesh material reduces the potential for trauma to the stomach lining, thereby improving tolerance. Likewise, the mesh material is very easily bent, twisted and folded, simplifying delivery and removal while easily conforming to the interior of the stomach 10.
As used herein, “mesh” or “mesh material” refers to an open material, fabric or structure having a plurality of spaced apart openings. Many types of mesh materials may be employed, including interwoven strands 23 (like a fabric) of indigestible materials (one woven example being depicted in
The intragastric device 20 is operable between a first elongated configuration, shown in
The yoke 28 is woven through the mesh member 22 at regular intervals between the distal end 30 and the proximal end 32. The yoke 28 may take many forms, but preferably comprises a thread such as a polypropylene suture, although many suture or thread materials may be employed. Other forms of the yoke 28 include structures such as plastic tubing or solid rods. A first end 30 of the mesh member 22 is closed, preferably by tying the suture 28 around the mesh tube to define a first button 24. It will be recognized by those skilled in the art that the first end 30 may be closed, and likewise the suture 28 connected to the first end 30, in numerous manners. For example, the plastic material of the mesh member 22 may be heated and melted to form the first button 24. The suture 28 may be then tied to the first end 30 and/or button 24, or the first end 30 may be melted around the suture 28. Likewise, the first end 30 may be tied in a knot to define the button 24. A separate stopper or other clamp may also form the button 24. Many variations for the button 24 and for connecting the suture 28 to the first end 30 will be readily apparent to those skilled in the art.
The transition of the mesh member 22 from the first configuration to the second collected configuration is depicted with reference to
The suture 28 may be woven through the mesh member 22 in many different manners, and a few preferred configurations are depicted in
It will be recognized by those skilled in the art that numerous configurations of the intragastric member 20 may be realized through variation of the size of the mesh member 22, the mesh material forming the mesh member 22, the type of yoke 28 employed, as well as the passing of the yoke 28 through the mesh member 22 following a pathway that is infinitely variable. For example, the mesh member 22 may not be tubular but may simply comprise a flat strip of material of constant or varying width, and the suture 28 may be woven along an irregular path. Additional examples of such variations of the intragastric device 20 are disclosed in copending U.S. patent application Ser. No. 10/151,720 filed May 27, 2002 and U.S. Patent Application 60/679,135 filed May 9, 2005, the disclosures of which are hereby incorporated by reference in their entirety.
In the first elongated configuration, the mesh member 22 generally has a length to width ratio that is about 400 to about 1000 for passage into the stomach 10, while in the second collected configuration the mesh member 22 generally has a length to width ratio that is less that about 5, and preferably about 1 (i.e. an about equal length and width) for residence in the stomach 10. As one example, a mesh member that has a length of 20 feet (uncollected), and a diameter of about 0.5 inches (diameter being considered about equal to the width), would have a length to width ratio of about 480 in the first elongated configuration.
Deployment of intragastric device 20 can be accomplished in a number of ways, depending on the size, number, and configuration of the devices, or according to physician or patient preference. Turning now to
The pusher 44 is also constructed from a cannula or other tubular member. The pusher 44 defines a plurality of coupling pawls 48 which are structured for engagement and translation of the mesh member 22 through the delivery lumen 46 of the delivery tube 42. As best seen in
In one preferred construction, the delivery sheath 42 has an inner diameter of 0.65 inches, while an outer diameter of the pusher tube 44 (measured to the distal tip 56 of the pawls 48) is approximately 0.50 inches. In a relaxed state, the mesh member 22 has a diameter of about 2 inches, resulting in substantial folding or overlap of the mesh member 22 within the delivery sheath 42. Preferably, the pawls 48 extend axially about 0.25 inch and are angled about 15-45 degrees (from a central axis of the pusher tube 44). The pawls 48 are unitarily formed with the pusher tube 44, typically by making a V-shaped cut in the material and manipulating the pawls 48 into their distally and radially outwardly projecting configuration.
It can be seen from
It will be recognized by those skilled in the art that the coupling pawls 48 of the pusher tube 44 may take numerous relative configurations. In the embodiment depicted in
An alternate embodiment of the delivery device 140 may utilize an alternately constructed delivery sheath 142 which assists in resisting the proximal motion of the mesh member 22 therein. As shown in
Turning now to
This construction also permits the pawls 248 to be unitarily formed with the pusher 244. That is, the edges 256, 258 may be shaped to form the pawls 248 at a distal end 252 of the pusher tube 244. The pawls 248 extend distally to a free end which is structured to pass through the openings in the mesh member 22. The pawls 248 are also radially aligned with the pusher 244 along the first and second longitudinally extending edges 256, 258, although the pawls 248 may project radially inward for engagement of the mesh member 22. Unlike the prior embodiment, the mesh member 22 is positioned inside the pusher 244, and extends along the inner surface 254 thereof. Reciprocal motion of the pusher 244 distally and proximally will cause the pawls 248 to engage and disengage, respectively, the mesh member 22 for advancement into the stomach 10 of the mammal.
Yet another embodiment of the delivery device 340 has been depicted in
It will therefore be recognized that the translation of the control member 356 and pawl wires 348 relative to the pusher tube 344 permits the pawl wires 348 to be withdrawn inside the pusher lumen 354, or to project distally from the end 352 of pusher 344. Thus, the pawl wires 348 are operable between a first expanded state as depicted in
It will also be recognized by those skilled in the art that in the embodiment of
The present invention also encompasses a method of treating obesity in mammals utilizing the mesh member 22 and delivery device 40, 140, 240, 340 to form an intragastric device 20 acting as an artificial bezoar. The method will be described with reference to the delivery device 40, but is equally applicable to all the delivery devices. Generally, the method includes the introduction of the delivery sheath 42, into the gastric lumen 12 of the mammal, the delivery sheath 42 defining the delivery lumen 46. The strip of digestive-resistant mesh material 22 is introduced into the delivery lumen 46. The mesh member 22 has distal end 30, proximal end 32, and a yoke 28 is connected to the distal 30 end of the mesh member 22. A pusher 44 is introduced into the delivery lumen 46 and includes a plurality of coupling pawls 48. The coupling pawls 48 are pointed distally to move the mesh member 22 distally upon distal translation of the pusher 44. The pusher 44 is reciprocated distally and proximally within the delivery lumen 46 to deliver the mesh member 22 into a stomach of the mammal. The mesh member 22 is bunched into a collected configuration sized to prevent the mesh member 22 from passing through the mammal's pylorus 14. The yoke 28 is connected to the proximal end 32 of the mesh member 22 to maintain the collected configuration thereof. Once the insertion and collection procedures are completed, any excess yoke (i.e. suture) 28 is removed.
To retrieve the intragastric device 20 and its mesh member 22, the mesh member 22 is returned from its collected configuration (
Accordingly, it will be recognized by those skilled in the art that the present invention provides an intragastric device, a delivery device therefore, and a method of treating obesity in mammals which is easy to place and retrieve. Ideally, the intragastric device acts as an artificial bezoar to achieve weight loss. At the same time, the present invention can potentially take up a smaller volume within the stomach than existing intragastric members such as balloons.
The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
This application claims the benefit of U.S. Provisional Application Ser. No. 60/762,926 filed on Jan. 27, 2006, entitled “INTRAGASTRIC DEVICE FOR TREATING OBESITY”, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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60762926 | Jan 2006 | US |