2005-10-21 Assigned to GIDYNAMICS, INC. reassignment GIDYNAMICS, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MELANSON, DAVID A., LEVINE, ANDY H.
A collapsible gastrointestinal anchor can be characterized in various embodiments by a radial force of about 0.1 Newtons (N) or greater at a compressed diameter of 25 millimeters (mm); by an average spring rate of about 13 Newtons/meter (N/m) or greater in a range of motion between a relaxed diameter and a compressive elastic deformation diameter; or by a radial force over the range of motion of about 0.1 N or greater. Typically, the anchor can be adapted to be retained within a subject's intestine, more typically in the duodenum, or particularly in the duodenal bulb just distal to the pylorus. A gastrointestinal implant device includes the collapsible gastrointestinal anchor and a floppy sleeve. The sleeve is open at both ends and adapted to extend into a subject's intestine, the anchor being coupled to a proximal portion of the sleeve. Also include are methods of implanting the gastrointestinal implant device in a subject, and methods of treating a subject for disease. The disclosed gastrointestinal invention leads to an improved ability to secure anchors and devices in the gastrointestinal tract while tending to minimize migration.
FIG. 1C is a graph of force versus displacement data for various anchor devices during loading (compression). Table 1 (below) shows the results. These mesh and laser cut stents have been used as stents for esophageal tumors. Stents cut from Nitinol tubing (“Laser cut 1” and “Laser cut 2”) have a range of motion of about 0.45 inches (about 11 mm), and a maximum relaxed diameter of about 0.8 inches (about 20 mm). Another example, “Mesh stent” has a range of motion of about 0.3 inches (about 8 mm) and a maximum relaxed diameter of about 0.7 inches (about 18 mm). Made for esophageal tumors, these values are not sufficient to anchor the nominal relaxed interior diameter of the adult duodenum, which is about 25 mm, nor its normal range of motion, which is about 25 to 40 mm.
Wave anchors were presented by applicants for the purpose of anchoring a sleeve in the intestine. Two wave anchors (“Wave 0.014” and “Wave 0.016”) have ranges of motion of about 1 inch (about 25 mm) and relaxed diameters of about 1.5 inches (about 38 mm), and can thus begin to address the diameter and range of motion of the intestine. Their spring rates are 0.0438 pounds/inch and 0.0722 pounds/inch (about 7.7 N/m and 12.6 N/m, respectively) and the force exerted by each (during loading) at 1 inch (25 mm), the nominal relaxed diameter of the duodenum, is 0.05 pounds and 0.04 pounds (about 0.2 N/m and about 0.16 N/m, respectively). (Force measurements have been made in pounds force. Conversion to metric units includes pounds force*4.448=Newtons force; pounds force/inch*175.1=Newtons/meter; 1 inch=25.4 mm) Moreover, while there is at present no known upper limit for radial force and spring rate in the intestine, it is believed that these lower radial forces, lower spring rates, and longer ranges of motion of these wave springs can allow for more natural motion in the intestine compared with the anchors in the preceding paragraph. It is believed that allowing the anchor to follow the natural motion of the intestine may provide more secure anchoring, may allow for better digestive system function and may tend to avoid subject discomfort. Thus, these wave spring anchors are believed to be superior to the anchors in the preceding paragraph. However, in experiments it was noted that these anchors tended to migrate in the duodenum.
Moreover, the anchor should be able to provide sufficient force over the range of motion of the intestine. In various examples (as will be explained in greater detail below for FIGS. 3A, 3B, and 4), it was determined that the nominal postoperative diameter tended to fall in a range where the loading radial force of the anchors at the top of the postoperative diameter range was between about 0.05 and about 0.1 pounds (from FIG. 3A and 3B; about 0.2N and about 0.4 N). It is believed that this radial force range at these diameters is thus associated in pigs with a long-term steady state expansion value. It is desirable to provide at least these forces over the range of motion, but not to exceed these forces at the expanded diameter to avoid over expansion of the gastrointestinal tract at the location of the anchor. Thus, in various embodiments, anchor 200 is characterized by a radial force over the range of motion of about 0.2 N or greater, more typically, about 0.3 N or greater, or particularly about 0.4 N or greater.
In various embodiments, anchor 200 can be characterized by an average spring rate over the range of motion. For example, in FIG. 2A, anchor 200 is compressed from a relaxed diameter 25 to a compressed diameter 26, and the radial restoring force 24 can be divided by the difference between relaxed diameter 25 and compressed diameter 26 to give a spring rate. Thus, for an anchor with a relaxed diameter of 60 mm and a force of 0.4 N at a compressed diameter of 25 mm can be calculated to have a spring rate of 0.4/(60-25)=13 N/m. Also, the average spring rate can also be calculated by recording compression force versus compression distance data and performing standard least squares analysis to obtain the average value of the force/distance slope, corresponding to the spring rate (N/m). Thus, in various embodiments, the anchor is characterized by an average spring rate of about 13 Newtons/meter (N/m) or greater in a range of motion, the range of motion being within a diameter range defined by a relaxed diameter and a compressive elastic deformation diameter. More particularly, the average value of the spring rate is between about 15 N/m and about 35 N/m.
FIG. 3A shows curves during loading (compression)for two disclosed wave anchors having relaxed diameters of 50 mm. The lower curve has a radial force at 25 mm compression of about 0.1 pounds (about 0.4 N), a radial force at 40 mm of about 0.05 pounds (about 0.2 N), and a substantially linear spring rate of about 18.5 N/m over a range of motion of almost 35 mm. The upper curve has a radial force at 25 mm compression of about 0.2 pounds (about 0.8 N), a radial force at 45 mm of about 0.06 pounds (about 0.24 N), and a substantially linear spring rate of about 32 N/m over a range of motion of almost 35 mm. Another anchor (curve not shown) was constructed with a radial force at 25 mm compression of about 0.18 pounds (about 0.8 N) and other characteristics similar to the upper curve. Upon implantation into pigs, it was found that these 50 mm anchors were secure and did not migrate.
It can be seen in FIG. 4 that for the 50 mm and 60 mm anchors that were followed by X-ray, the nominal postoperative diameter tended to fall in a range where the radial force of the anchors at the top end of the respective ranges was between about 0.05 and about 0.1 pounds (from FIG. 3A and 3B; about 0.2N and about 0.4 N). For example, for the 50 mm anchors, the nominal postoperative diameter was about 30 to about 40 mm and the radial force of the anchors at 40 mm was between about 0.05 and about 0.1 pounds (from FIG. 3A; about 0.2N and about 0.4 N). For the 60 mm anchors, the nominal postoperative diameter was about 40 to about 50 mm and the radial force of the anchors at 50 mm was between about 0.05 and about 0.1 pounds (from FIG. 3B; about 0.2N and about 0.4 N). It is believed that this radial force range at these diameters is thus associated in pigs with a long-term steady state expansion value. It is desirable to not exceed these forces at the expanded diameter to avoid over expansion of the gastrointestinal tract at the location of the anchor.
Within the implant device 600 at the proximal end including the first proximal opening 606 is a collapsible self-expanding anchor 602 in the form of a stent (e.g., an embodiment of anchor 200 in FIG. 2A-2D). The anchor 602 can include a plurality of opposed barbs 608 for anchoring the implant device 600 to the muscular tissue of the duodenum 104. The diameter of the anchor 602 is dependent on the diameter of the duodenum 104 (FIG. 1) about 1.0″ to 2.5″ (about 25 mm to about 65 mm) based on human anatomy variations. In one embodiment, the length ‘l’ of the anchor 602 is selected to reside within the bulbous duodenum 119.
Further examples of methods and apparatus for implanting the anchors and devices of the invention, anti-bucking devices, methods of treatment, details of construction of the anchors, sleeves, impregnation of the sleeves with drugs for treatment of various conditions, and the like are provided in Meade et al U.S. Utility application Ser. No. 10/858,851, filed Jun. 1, 2004; Levine, et al, Atty. Docket No.: 3588.1010-000: U.S. Provisional patent application Ser. No. 60/611,038; filed: Sep. 17, 2004; Levine, et al, Atty. Docket No.: 3588.1012-000: U.S. Provisional Patent Application Ser. No. 60/645,296; filed: Jan. 19, 2005; and DiCesare, et al Atty. Docket No.: 3588.1013-000: U.S. Provisional Patent Application Ser. No. 60/645,287, filed: Jan. 19, 2005. The entire teachings of these documents are incorporated herein by reference.
a collapsible gastrointestinal anchor, coupled to a proximal portion of the sleeve and characterized by a radial force of about 0.1 Newtons (N) or greater at a compressed diameter of 25 millimeters (mm).
21. The gastrointestinal implant device of claim 20, the radial force at 25 mm being measured while unloading the anchor from a compressed state.
22. The gastrointestinal implant device of claim 20, the radial force at 25 mm being about 0.3 N or greater.
23. The gastrointestinal implant device of claim 20, characterized by a relaxed diameter of about 40 mm or greater.
24. The gastrointestinal implant device of claim 20, characterized by a relaxed diameter of between about 45 mm and about 65 mm.
25. The gastrointestinal implant device of claim 20, the radial force being about 0.2 N or greater over a range of motion of about 20 mm or greater, the range of motion being between a relaxed diameter and a compressive elastic deformation diameter.
26. The gastrointestinal implant device of claim 20, further comprising barbs.
27. The gastrointestinal implant device of claim 20, characterized by a compressive elastic deformation diameter of about 12 mm or less.
28. The gastrointestinal implant device of claim 20, the anchor being made of Nitinol wire.
a collapsible gastrointestinal anchor, coupled to a proximal portion of the sleeve and characterized by an average spring rate of about 13 Newtons/meter (N/m) or greater in a range of motion of about 20 mm or greater, the range of motion being within a diameter range defined by a relaxed diameter and a compressive elastic deformation diameter.
30. The gastrointestinal implant device of claim 29, the spring rate being measured while unloading the anchor from a compressed state.
31. The gastrointestinal implant device of claim 29, characterized by a relaxed diameter of about 40 mm or greater.
32. The gastrointestinal implant device of claim 29, the average value of the spring rate being between about 15 N/m and about 35 N/m.
33. The gastrointestinal implant device of claim 29, the range of motion being about 30 mm or greater.
a collapsible gastrointestinal anchor, coupled to a proximal portion of the sleeve and characterized by a radial force of about 0.1 Newtons (N) or greater over a range of motion of about 20 mm or greater, the range of motion being within a diameter range defined by a relaxed diameter and a compressive elastic deformation diameter.
35. The gastrointestinal implant device of claim 34, the radial force being measured while unloading the anchor from a compressed state.
36. The gastrointestinal implant device of claim 34, the radial force being about 0.2 N.
37. The gastrointestinal implant device of claim 34, characterized by a relaxed diameter of about 40 mm or greater.
38. The gastrointestinal implant device of claim 34, the range of motion being about 30 mm or greater.
collapsible anchor means for providing substantially constant force against gastrointestinal tissue over a range of motion occurring between a relaxed diameter of about 40 mm or greater and a compressive elastic deformation diameter of the anchor.