Patent Application
20180311484
The present invention generally relates to the field of devices that temporarily occlude spaces within the body to provide a therapeutic effect.
According to 2010 World Health Organization data, 198 million Americans over the age of 15 are above target weight. Of these individuals, 89 million are considered overweight (25<Body Mass Index<30) and 109 million are considered obese (Body Mass Index>30). Worldwide, more than 1.4 billion adults age 20 and over are overweight, and 500 million are obese. Obesity places patients at increased risk of numerous, potentially disabling conditions including type 2 diabetes, heart disease, stroke, gallbladder disease, and musculoskeletal disorders. Compared with healthy weight adults, obese adults are more than three times as likely to have been diagnosed with diabetes or high blood pressure. In the United States it is estimated that one in five cancer-related deaths may be attributable to obesity in female non-smokers and one in seven among male non-smokers (>=50 years of age). On average, men and women who were obese at age 40 live 5.8 and 7.1 fewer years, respectively, than their healthy weight peers.
Gastric bypass surgery is the current gold standard treatment for patients with a body mass index (“BMI”) of greater than 40. Gastric bypass surgery is also an option for those with a BMI between 35-39 with obesity-related co-morbidities. While gastric bypass surgery results in decreased food consumption and weight loss for a majority of recipients, it requires life-altering, permanent anatomic modifications to the gastrointestinal tract and can result in severe complications. Gastric bypass and related surgical procedures are also expensive, costing about $22,500 (by laparoscopy). For these reasons, only about 250,000 surgical obesity procedures are performed per year in the US.
For the vast majority of the overweight and obese population for whom surgical obesity procedures are not appropriate, few efficacious and affordable interventions are currently available. Diet and exercise remain the front line approaches to obesity, however this approach has at best slowed the growth of the epidemic. To date, drug therapies have dose limiting side effects or have lacked meaningful long term efficacy.
One less-invasive intervention that has begun to gain popularity is an intragastric balloon. Intragastric balloons can be placed endoscopically or positioned using other methods and generally must be removed endoscopically or rely on the body's natural digestive processes for removal.
The method of fabrication discussed herein are intended to provide an efficient method of fabrication for balloon devices for the treatment for obesity.
The present invention relates to devices and methods for occupying a space within a patient's body. In particular, the devices and methods can be used within a gastric space. However, the devices and methods can be used in any part of the body. In greater particularity the present invention relates to fluid valves for use in these space occupying devices.
The devices described herein can also be used for delivery of drugs, pharmaceuticals, or other agents where such items can be delivered on a skin of the device, within a reservoir, in a filler of the device, or anywhere on the device. Such agents can be released over time.
The present disclosure includes medical devices for use with a liquid filler material and for occupying a space within the patient's body. In one example such a medical device includes a liquid impermeable surface material forming a device body having an interior reservoir, the device body having a deployment profile and expandable to an active profile upon receiving the liquid filler material within the interior reservoir; a liquid tunnel having at least one wall and defining an elongated passage, at least a portion of the liquid tunnel extending within the interior reservoir, and where the at least one wall of the liquid tunnel is pre-disposed to obstruct the elongated passage to prevent fluid flow therethrough; a fluid conduit having a distal portion located within the elongated passage of the liquid tunnel to create a fluid path through the elongated passage for delivery of the fluid into the interior reservoir, and where the fluid conduit is removable from the liquid tunnel, such that upon removal of the fluid conduit, the at least one wall of the liquid tunnel obstructs the elongated passage to prevent fluid therethrough the elongated passage; and a release channel formed by an elongated section of liquid impermeable material, where the elongated section of liquid impermeable material is inverted into the interior reservoir and temporarily restrained therein, wherein, when temporarily restrained, the release channel is closed to prevent liquid transfer to or from the patient's body.
The present disclosure includes methods of manufacturing expandable devices. The expandable devices can include medical devices as described herein as well as devices used in non-medical applications.
In one example, the present disclosure includes a method of manufacturing expandable devices, comprising the steps of: providing a multi-layer thin film of polymeric material, the multi-layer thin film of polymeric of material comprising a thin film backing layer and a thin film working layer and, wherein the thin film backing layer is disposed on a first side of the thin film working layer; positioning the multi-layer thin film on an open frame and heating the multi-layer thin film; forming the multi-layer thin film into a device section having a predetermined shape using differential gaseous pressure to conform the multi-layer thin film to a mold, the device section having an inner surface and an outer surface, one backing layer comprising the outer surface, the predetermined shape having a flange region; disposing a first device section together with a second device section such that the working layers of the first and second device section are juxtaposed with the flange region of the first device section being in alignment with the flange region of the second device section; creating an access hole in at least one of said two device sections; joining the flange regions of the device sections to form a fluid tight seam around the flange region; trimming an excess material from around the flange region; and inverting the device though the access hole.
In another variation, the method of manufacturing expandable devices comprises providing a thin film of polymeric material, the thin film of polymeric of material comprising a backing side and a working side; positioning the thin film on an open frame and heating the thin film; forming the thin film into a predetermined shape using differential gaseous pressure to conform the thin film to a mold, the predetermined shape having an inner surface and an outer surface, the predetermined shape having a flange region; forming at least two pre-determined shapes to respectively provide at least a first device section and a second device section; disposing the first device section together with the second device section such that the working side of the first and second device section are aligned at the respective flange regions; creating an access hole in at least either the first or second device sections; joining the flange regions of the first and second device sections to form a fluid tight seam around the joined flange regions; trimming an excess material from around the flange region; and inverting the device though the access hole.
The method further comprising sealing the access hole after inverting the device through the access hole.
The method can further comprise forming the film into a device section comprises the step of forming a convex and a concave device section.
In an additional variation, the step of forming a convex and a concave device section comprises using a dual mold to produce the convex and the concave device sections simultaneously. Moreover, if a second thin film backing layer can be disposed on a second side of the thin film working layer. In such a case, the method can further comprise removing the second backing layer before heating the multi-layer thin film.
In an additional variation, the method further comprises cutting an access hole through at least one device section, the hole disposed to avoid intersection with the flange region.
The method can also include exposing one side of the working layer by removing a backing layer.
In an additional example, the method further comprises disposing an additional device subcomponent between the aligned working layers of the first device section together and the second device section.
Joining of the flange regions of the device sections can include any process known by those skilled in the art. Such processes can include joining by thermal, mechanical, or chemical joining.
The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.
The foregoing and other objects, features and advantages of the methods, devices, and systems described herein will become apparent from the following description in conjunction with the accompanying drawings, in which reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings:
FIG. 10B1 shows a schematic cross sectional view of tunnel taken along line 10B-10B of
FIGS. 10B2 and 10B3 show schematic cross sectional views of two variations of the tunnel valve of
FIG. 10H1 to 10H3 show a schematic cross-sectional view of a tunnel valve including a packing substance between layers of the tunnel valve and a conduit taken along line 10H-10H of FIG. 10B1
The following illustrations are examples of the invention described herein. It is contemplated that combinations of aspects of specific embodiments or combinations of the specific embodiments themselves are within the scope of this disclosure. While the methods, devices, and systems described herein are discussed as being used in the stomach or gastric space, the devices, methods, and systems of the present disclosure can be can be used in other parts of the body where temporary occlusion of a space might be required or beneficial. The present disclosure is related to commonly assigned to US Publication No. 2011/0295299 filed Mar. 2, 2011, the entirety of which is incorporated by reference.
For a device used in the digestive tract/gastric space, the device assembly 100 can be positioned within the body either by natural ingestion or the use of a delivery system (such as a catheter, endoscope, or other medical device). The delivery system can optionally comprise an oral dosage form, not illustrated, which facilitates the ingestion of a relatively large object. In other embodiments the system comprises a tether that allows manipulation or control of the placed construct from outside of the body. The assembly 100 can also be placed in the stomach by more invasive surgical or endoscopic procedures.
In
The variation shown in
In other variations, the device assembly 100 can include an empty reservoir that can be deployed into the body and subsequently filled with a filler material or other substance. For example, such variations can include a liquid filler material that is delivered to the reservoir through a conduit. The volume of liquid required to expand the device into a desired active profile can pre-determined. In some variations, the volume can be determined by measuring the back pressure in the conduit or pressure within the reservoir using any number of pressure detecting elements.
As noted herein, the skin 102 includes a release material 106 coupled thereto, where the release material 106 allows for initiating release of the assembly 100 from the body shortly after degradation, activation, or breakdown of the release material. Once the device assembly 100 is in the active profile, it can remain in the active profile for a pre-determined amount of time or until the patient experiences a desired therapeutic effect. To initiate release of the device assembly 100 from the body, an exogenous material, substance or stimulus is administered to the patient. The substance can comprise a fluid or other activating agent having properties that either directly or indirectly act on the release material to disrupt the barrier and allow the contents of the reservoir to be exposed to the body. For example, the exogenous substance can comprise a heated fluid that melts the release material. Alternatively, the exogenous material can change a temperature and/or an acidity of fluids in the stomach such that the enhanced properties of the fluids begin to act, either directly or indirectly, upon the release materials. In additional variations, the release material can comprise a material or materials that effectively form a barrier as discussed herein and are separated or disengaged by the use of an exogenous stimuli (e.g., a magnetic field, ultrasound, IR heating, coherent light, electromagnetic signals, microwave field, etc.).
When using a conduit 114 that extends outside of the body, a physician can deliver a hydrating liquid, such as water or distilled water through the conduit 114. Generally, a pre-determined volume of liquid can be manually or mechanically pumped into the exterior end of the conduit wherein the volume of liquid is pre-determined based on a particular size of the device assembly or based on a desired active state. In some variations, the volume of liquid can also depend on the length of conduit.
The conduit 114 can be used to transfer a substance or into the reservoir 104 of the device. In the illustrated variation, the conduit 114 transfers fluid from outside of the patient's body into the reservoir 104 after deployment of device assembly 100 within the body. Alternatively, or in combination, a fluid transfer member can comprise a wick type device that transfers liquids or other fluids from within the body to the reservoir.
As noted above, this particular variation of the assembly 100 includes a conduit 114 that is coupled to the skin 102 through the fluid path 112 and extends into the reservoir 104. Alternatively, a conduit 114 can be directly coupled to the skin. When the device assembly 100 achieves the active state the conduit 114 can be pulled from the device assembly 100. For those variations that employ a sealable fluid path 112, withdrawal of the conduit 114 causes the sealable fluid path 112 to collapse or be compressed thereby preventing the contents of the reservoir 104 from escaping from the device assembly 100. Alternatively, or in combination, the sealable fluid path 112 located within the reservoir 104 can be sealed due to the increased pressure within the reservoir. In other words, the same pressure within the reservoir 104 that causes expansion of the device 100 also causes the sealable fluid path 112 to close, compress or otherwise reduce in diameter to a sufficient degree that material is unable to escape from the reservoir through the sealable fluid path 112.
In certain variations, the conduit 114 is held in place in the sealable fluid path 112 by friction alone. Withdrawal of conduit occurs by pulling on the conduit in a direction away from the device 100. During the initial stages of this withdrawal activity the expanded device 100 generally moves upwardly with the conduit in the stomach, until the expanded device 100 reaches the esophageal sphincter. With the device assembly restrained from further upward movement by the sphincter, the conduit 114 may then be withdrawn from the fluid path and from the patient by additional pulling force.
Upon withdrawal of conduit 114 the fluid path effectively seals, as described herein, and prevents migration of fluids or other substances into and out of the reservoir. In certain variations the fluid path seals on its own after removal of a conduit or other member located therein. In additional variations, hydrostatic pressure and/or pressure caused by the expanded filler acting along the length of the fluid path can aid in sealing of the fluid path.
In alternate variations, the release material, or additional areas on the skin degrade or become unstable due to the passage of time in the normal gastric environment. In such cases, the additional areas can serve as a safety mechanism to ensure release of the device after a pre-determined period of time. For example, in the variation shown in
In the embodiment shown in
The transition from initial, unexpanded state construct 1000 to the active state can be effected by increasing the volume of filler material 1200 enclosed in reservoir 1010. Additionally, the volume can be expanded through expansion and/or swelling of the filler material already inside the reservoir 1010. For example, as was described in commonly assigned U.S. patent application publication number US2011/0295299, one exemplary embodiment filler material 1200 in the initial state is a pre-determined volume of dry hydrogel granules. The dry hydrogel granules can swell, for example, between 10 and 400 times their dry volume when exposed to an appropriate liquid, generally an aqueous solution.
In the variation shown in
Assemblies 1000 under the present disclosure can comprise a material surface or skin 1013 that is substantially impermeable to liquids and/or gases. In these embodiments, filler material 1200 can be, respectively, a liquid or a gas. Additionally, filler material 1200 can be a fluid-swellable material such as hydrogel, which, when hydrated, becomes a solid, semisolid or fluid-like gel or slurry. As illustrated in
As noted above, in certain variations, where the device assembly 1000 comprises a substantially liquid impermeable material surface, a construct 1000 in the expanded active profile can remain in stomach or other portion of the body indefinitely until released. Therefore, as noted above, devices of the present disclosure can include a release material 1400, which allow the construct 1000 to reduce in size from the active profile and ultimately pass through the body. Such an active release material 1400 configuration allows for on-demand release of the construct. As noted above, once activated, degraded, or otherwise made unstable, the release material allows migration of filler material from the reservoir and device assembly. In some variations, activation of the release material opens a passage in the skin 1013 of the device 1000. Alternatively, or in combination, activation of the release material can result in reduction of the integrity of the skin forming the barrier about the reservoir. Once the barrier is compromised, the filler material can safely pass into the body. Regardless of the means, the activation of the release material and release of the filler material collapses the device 1000 leading to egress or removal of the device 1000 through the body (in this variation through the lower gastro-intestinal track). As noted above, variations of the devices described herein include a release material that is activated by exposure to an exogenous substance.
In certain variations, the device assembly 1000, in the active profile, comprises a highly oblate spheroid wherein the skin 1013 can be a thin, film-like material that is soft, tear-resistant, flexible, substantially inelastic, and non-self-adhesive. Such features can be beneficial for a device that is to be compressed into a small oral dosage form for administration. In certain examples, the skin 1013 comprised a 0.0015 inch thick polyether polyurethane film. In a simple variation, an oblate spheroid can be created from skins forming an upper material surface and a lower material surface, wherein upper material surface and lower material surface are sealed to each other as shown by seam 1004 in
In some variations, as illustrated in
As illustrated in
The orifice or lumen 1020 forms a fluid path that allows a remainder of the fluid transport member 1100 to deliver fluids into the reservoir. In this variation the fluid transport member 1100 further comprises a conduit. However, as noted herein, the fluid transport member can comprise a wick type device or any fluid source that allows delivery of fluids into the reservoir of the device. As also noted herein, a variation of the device comprises an attachment of conduit 1100 to a portion of tunnel valve 1110, wherein the attachment may be direct or indirect and wherein, in some variations the attachment is releasable to permit conduit 1100 to be detached, withdrawn, or removed from the tunnel valve 1110. Withdrawal or removal of conduit 1110 from orifice 1020 permits the tunnel valve 1110 to prevent egress of fluids or other substances from within the reservoir. Sealing of the tunnel valve 1110 can occur via a rise in pressure within the reservoir. Alternatively, or in combination, a number of other mechanisms can result in sealing or closure of the orifice 1020 in the tunnel valve 1110. For example, in additional variations the surfaces forming the lumen 1020 can seal upon contact or the length of the tunnel valve 1110 combined with its flexible nature can simply make it difficult for substances, such as an expanded hydrogel, to travel through the elongated portion 1022 of the tunnel valve.
In one variation of the tunnel valve 1110, as illustrated in
Some examples of materials used to form a tunnel valve include thin, film-like materials. For example, variations include tunnel valve materials that have properties similar to the material used in material surface or skin of the device. Additional materials include but are not limited to polyurethane, nylon-12, and polyethylene. In certain variations, Suitable materials typically have a durometer hardness of 80 Shore A or softer and are extruded with a glossy finish to enhance cohesion and tackiness. Layers of material in exemplary tunnel valves can typically be between 0.001 inch or less and 0.1 inch thick. In one example a tunnel valve includes a single layer thickness of 001 inch. One suitable layer material is a 0.001″ thick, high tack polyurethane film.
The length of the elongate portion 1022 that extends within the reservoir of the device assembly may be short, for example, 0.1 inch or as long as the diametric width of the device assembly. In one exemplary valve the length within the reservoir is approximately 1.25 inches and the width of that portion is approximately 0.75 inches wide.
As discussed above, variations of a device assembly include a release material that is coupled to a portion of the skin to form a barrier to retain substances within a reservoir of the device.
The release area 128 of the invaginated section 126 ordinarily forms a passage that is fluidly sealed by a release material 106. The release material can comprise a mechanical closure (such as a staple-type structure or a filament that ties together the invaginated structure). Alternatively, or in combination, the release material 106 can comprise a temporary seal or other joining of the edges of the invaginated section 126. In additional variations, the release material can extend outwardly from an exterior surface of the skin. In some variations, the release material 106 is disposed on the invaginated portion 126 sufficiently close to the skin to be affected by a temperature increase caused by delivery of the exogenous substance.
In certain variations, the inverted section 126 forms a release area 128 that provides a passage to provide fluid communication between the reservoir and the exterior of the device assembly. This feature allows release of any fluids or material retained within the reservoir to allow the device to reduce in size and pass from the body. The opening can be located at the end of the passage, i.e., at the open edge of the material that is closed together. Alternatively, the wall forming the passage can be porous in an area beyond the point at which the inverted section 126 is bound (e.g., the area disposed inwardly relative to release material 106).
In additional variations, the inverted section 126 includes an energy storage element that encourages a rapid and more complete opening of the release area 128. Variations of the internal energy storage element can include a solid structure, or a structure that allows passage of fluids. The energy storage element can include a compressible elastic material, for example, a latex foam. In some variations internal energy storage element is generally cylindrical with a diameter at least fractionally smaller than the diameter of the passage in the inverted section 126. When device 100 is deployed in the body, release material 106 is tied firmly around the inverted section 126 at the position of the internal energy storage element, thereby simultaneously sealing the invagination and compressing the internal energy storage element. The resilience of the elastic material in the internal energy storage element creates a tensile force in release material 106 that is greater than the tension in the release material tie used to seal an invagination alone.
In another variation, not illustrated, the energy storage element is disposed outside of inverted section 126. An external energy storage element, for example a retaining ring, is used to increase the tension in the cinched and tied filamentary release material 106. The increased tension encourages the release material to break apart sooner, more rapidly, and more completely than it otherwise would. A suitable external energy storage element may be made using, for example, a special order, 5 millimeter diameter, Hoopster® retaining ring, available from Smalley Steel Ring Company, 555 Oakwood Road, Lake Zurich, Ill. 60047.
The release area 128 in each of the variations of the inverted section 126 is initially sealed or closed off by a release material that is coupled, directly or indirectly, to a portion of the skin to form a barrier to retain substances within a reservoir of the device. In many variations the release material is filamentary. Examples of release materials that are available in filamentary form can include Polyglycolide (PGA), Polydioxanone (PDS), Poly(lactic-co-glycolic acid) (PLGA), Polylactide (PLA), Poly (4-hydroxybutyric acid) (P4HB), Polyglactin 910, and Polycaprolactone (PCL).
In such variations, the release material in the expanded device assembly degrades over time by hydrolysis where the rate of hydrolysis varies with material selection and liquid filler pH. In variations wherein the release material is PCL the release material can also degrade by elevating the temperature of the release material since PCL softens, melts, and weakens above a pre-determined temperature. In some cases the pre-determined temperature is greater than normal body temperature. Accordingly, in such variations, the exogenous substance can comprise a heated fluid that can raise the temperature of the PCL without causing injury to the adjacent areas of the body. As the PCL release material degrades, the structural integrity of the joined region of the release section (such as the inverted section 126) decreases. In one example, the release material is a modified PCL, wherein the modification comprises lowering the melting point of unmodified PCL from its normal melting temperature to a human-tolerable temperature.
Examples of the release material can include poly(caprolactone) or PCL. In such variations, PCL softens, melts, and weakens above a pre-determined temperature. In some cases the pre-determined temperature is greater than normal body temperature. Accordingly, in such variations, the exogenous substance can comprise a heated fluid that can raise the temperature of the PCL without causing injury to the adjacent areas of the body. As the PCL release material degrades, the structural integrity of the joined region of the release section (such as the invaginated section 126) decreases. In one example, the release material is a modified PCL, wherein the modification comprises lowering the melting point of unmodified PCL from its normal melting temperature to a human-tolerable temperature.
For example, an on-demand degrading construct composed of nylon-12 can be constructed by first fabricating a 1″ circular annulus of 1.5 mil polyether polyurethane. A circular degradable patch of poly(caprolactone) (PCL) (with a modified melting point, Tm, equal to ˜47° C.; available from Zeus Industrial Products of Charleston, S.C., USA) can be RF-welded to the polyether polyurethane annulus, covering the hole, creating a Tm-modified PCL patch surrounded by a rim of polyether polyurethane. The polyether polyurethane rim can then be RF-welded to a sheet of nylon-12, which can then be used for further construction.
Examples of release materials can include biocompatible manufactured polymers. Table 1 is a compilation of the degradation properties of several biocompatible materials that can be extruded or otherwise manufactured in filamentary form and which also can be predictably degraded. Some of these materials, poly(vinyl alcohol) are stable in dry environments but dissolve very quickly in moist environments. Some biocompatible polymers, for example co-polymers of methacrylic acid and methyl-methacrylate, dissolve in liquids having physiologically relevant pHs. For example, they remain stable at pH <7.0 but dissolve at pH >7.0. Other polymers, for example Poly(caprolactone), remain stable at typical gastric temperatures but melt in seconds at temperatures above a pre-determined melting point.
In some variations, polymers that degrade by gradual hydrolysis may be used for the release material. The degradation times of various polymers, under various degradation conditions, can range from about 2 weeks to about 6 months, where the degradation time depends on parameters such as degradation liquid pH, suture construction (e.g., stranded or monofilament), and filament diameter. In general, polymers last longest when exposed to distilled, neutral pH water and degrade more quickly when immersed in acidic or basic pH liquid.
The degradation times for several exemplary materials are tabulated in Table 1. The experimentally determined degradation times in the table were determined in simulated use conditions; that is, as illustrated in
As the release section opens the reservoir to the surrounding environment the opening provides an open path out of the device assembly. The open path allows the contents of the device assembly, such as the filler material, to become exposed to the gastric contents and freely to exit reservoir. When positioned within the stomach, normal gastric churning assists in emptying the contents of the device assembly allowing for the entire device along with its contents to pass from the body. In some variations, the membrane that forms the skin will provide little or no structural support. This configuration allows the body's natural squeezing strength to be sufficient to extrude any reasonably viscous substance out of the device assembly.
In one example, the release material can range from 25 microns thick; up to 2.5 millimeters thick. In another example, release material is a modified poly(caprolactone) with melting point TM=47° C. (available from Zeus Industrial Products of Orangeburg, S.C. USA). In additional embodiments, degradable patch 106 may be poly(glycolic acid) or poly(L-lactide acid) (available from Poly-Med, Inc of Anderson, S.C.).
Material Surface or Skin
The type of material or skin will depend upon the intended application. In some variations, a skin will be chosen as a balance of selecting a sufficiently thick film-like material that has adequate strength. For example in some variations, tear resistance can be preferred to enable the finished construct to be compression into as low a volume capsule as possible. The inventors have determined that thin films with a thickness ranging from 0.5 mils to 4 mils are generally suitable. However, the devices described herein can comprise a greater range of thicknesses depending upon the particular application, including a range of thicknesses in different parts of the same construct. In some embodiments, the film-like material must be weldable or adherable to other materials such as might be used in valves 1110, filler material release mechanisms 1400, and/or attachment interfaces as described herein.
In additional embodiments, the film-like material exhibits low transmission rate of filler material, both before and after device expansion. In some embodiment the film-like material exhibits a low moisture vapor transmission rate. Additionally, some film-like material also exhibits high chemical resistance to the variable conditions encountered in the stomach. These conditions include low pH, high salt, high detergent concentrations (often in the form of bile salt reflux), enzymatic activities (such as pepsin), and the variable chemistries of chyme that depend upon the nature and content of consumed food. For those devices used in the gastric space, the material must also be comprised of biocompatible materials that can safely be in contact with the gastric mucosa for the duration of the treatment course.
The devices described herein can use numerous thermoplastic elastomers, thermoplastic olefins and thermoplastic urethanes that can be extruded or cast into single-layer or multi-layer films which are suitable for embodiments of the gastric device. Example base resins that may be employed include polypropylene, high-density polyethylene, low density polyethylene, linear low density polyethylene, polyester, polyamide, polyether polyurethane, polyester polyurethane, polycarbonate polyurethane, bi-axially oriented polypropylene, Polyvinylidene chloride, ethylene vinyl alcohol copolymer, and Ethyl Vinyl acetate. Some embodiments comprise single layer films whilst other embodiments comprise multiple layer films. Other embodiments consist of multilayer films including one or more tie layers to prevent layer separation.
In some embodiments, the film-like material may be coated with other materials. For example, in some embodiments hyaluronic acid coatings can be employed to improve softness and lubriciousness. In other embodiments, coatings such as Parylene® can be applied to improve the chemical resistance of the gastric mucosa-exposed film surface. In some embodiments, wax coatings, PVDC coatings, vacuum-metallization, or Parylene® coatings may be applied to the surface of the film to reduce its moisture vapor transmission rate.
In one example, the film-like material used comprised a 1.5 mil polyether polyurethane film. In other embodiments the film-like material is a 1 mil nylon 12 film or a 1.5 mil LLDPE film. In another example, the film-like material consisted of a multi-layered structure comprising an outer layer of polyurethane, a middle layer of PVDC or EVOH, and an inner layer of polyurethane.
Filler Material
The devices described herein comprise two general types; those that are filled with a fluid filler material and those that are filled with a swellable material that is in an unswollen state during ingestion and swells when hydrated by gastric liquids or an exogenous liquid. Generally, a swellable filler material that has a high swelling capacity and achieves a semi-solid consistency is useful to enable the finished construct to be compressed into as low a volume initial state as possible but still maintain rigidity once expanded. However, unless specifically noted, variations of the device can employ a number of different types or combinations of filler materials. During various experiments, it was determined that superabsorbent hydrogel polymers with a mass:mass swelling capacity of between 100 and 1000 are generally suitable, where a mass:mass swelling capacity of 100 is defined herein to mean that 1.0 g of dry hydrogel will absorb water and swell to become a semi-solid mass of 100.0 g.
Typically, suitable hydrogels swell maximally in the presence of distilled water and a number of these hydrogels also de-swell (releases bound water) in the presence of the variable environmental parameters encountered in the stomach. For instance, parameters such as pH, salt concentration, concentrations of emulsifying agents (often in the form of bile salt reflux), enzymatic activities (such as pepsin), and the variable chime chemistries, which depend upon the nature and content of consumed food can affect the swelling/deswelling behavior of certain hydrogels. Typical hydrogel swelling times range from between 5 minutes and 1 hour. In one variation, the hydrogel fully swells in under 15 minutes and fully de-swells in less than 10 minutes after exposure in certain environments. Many hydrogels are supplied with particle sizes distributed between 1 and 850 microns. In certain variations, gastric applications benefit from the use of hydrogel particle sizes distributed between 1 and 100 microns. In addition, the hydrogel must also be comprised of biocompatible materials that can be safely in contact with and excreted by the gastrointestinal tract. Examples of such biocompatible superabsorbent hydrogel polymers that possess swelling capacities, swelling times, and de-swelling times suitable for embodiments of gastric construct include poly(acrylic acid), poly(acrylamide), or co-polymers of poly(acrylic acid) and poly(acrylamide). Another such material that can be used as a filler material is a crosslinked poly(acrylic acid) with particle size distribution ranging from 1-850 microns and swelling capacity of 400.
Shapes
As discussed above, certain variations of the device approximate a highly-oblate spheroid comprising a diameter in the X-Y plane and a thickness along the Z-axis as illustrated in
Liquid Transfer Valves
As noted above, the device assemblies described herein can include a fluid transport member 110 that serves to deliver fluids into the reservoir. One example of such a fluid transport member is a wick that includes a filamentary material capable of conducting a liquid from one end to the other by capillary action. The wick can extend from the interior of the device reservoir to outside the device skin, typically just several millimeters beyond the skin although longer wicks may be used. In another example, the liquid transfer mechanism 1100 comprises a fluid conduit 114, tube, or catheter that, after the device is extends from the deployed device in the patient's stomach to outside of the patient where it is connected to a source of filling fluid. In many embodiments the fluid flow through the fluid transport member is preferably shut off once the device has reached its desired deployment profile. In embodiments comprising a wick-like fluid transport mechanism the fluid flow may be shut off by pinching down on the wick while in embodiments comprising a catheter-like fluid transport mechanism the fluid flow is halted externally and the catheter-like mechanism is withdrawn from the device first and from the patient second. When the catheter-like mechanism is withdrawn from the device it is necessary to seal the orifice through which the catheter passed through the skin of the device. In many of the assemblies described herein fluid flow is inhibited by a self-sealing, two-layer valve. In other embodiments the self-sealing valve has more than two layers.
In yet other embodiments liquid transfer mechanism 1100 comprises a mechanical valve. Mechanical valves of suitably small dimensions, comprising biocompatible materials, are well known in the art and are commercially available. A mechanical valve that serves as liquid transfer mechanism 1100 comprises a one-way or “check” valve design which allows fluid to enter reservoir 1010 but prevents fluid from exiting the reservoir. Alternatively, a mechanical valve that serves as liquid transfer mechanism 1100 may have a normally open state but which self-closes when internal fluid pressure is greater than external fluid pressure.
This flow path is indicated by the dashed arrow in
In some variations the design may be simplified to comprise just two layers of fluid impermeable material through which passage holes have been created to allow the fluid transport member to pass. This variation is discussed further below in conjunction with
Turning back to FIG.
In some embodiments valve 232 comprises a filler material containment layer 242. Generally, containment layer 242 is at least partly fluid permeable and simultaneously able to contain filler material 234, in its dry or its hydrated state, within device 230. In some embodiments filler material containment layer 242 is also a flow control layer; that is, a single layer in valve 232 can simultaneously be a part of the flow control function of valve 232 and perform the filler containment function of containment layer 240. For example, laser micromachining may be used to create microperforations in one region of an otherwise fluid impermeable membrane. The microperforated region functions as the containment layer while the unperforated region can function as the flow control layer.
Similarly, in variations in which the filler material is a fluid or slurry material that is delivered to the reservoir by a conduit or catheter, each of two fluid impermeable may be punctured by catheter passage holes 242A, as illustrated in
As illustrated in
In these exemplary embodiments of a hybrid valve, the flow control layer disposed on the internal side of the valve preferably can also function as filler material containment layer, with containment being achieved by the mesh comprising permeable patch. Alternatively, a separate innermost filler material containment layer must be added to the assembly.
In other embodiments, hybrid flow control layer is fabricated by joining a patch of permeable material and a patch of impermeable edge-to-edge, wherein the joint may be a butt joint, for example, or a lap joint, for a second example, wherein further the outer periphery of the edge-joined materials is designed to fill or cover orifice. In another exemplary embodiment of a hybrid valve the skin itself can serve as one of the flow control layers.
Another variation of a multi-layer, self-closing valve is a tunnel valve.
FIGS. 10B1-10B3 show a cross sectional view of tunnel 330 taken along line 10B-10B of
One variation of the tunnel valve, illustrated in FIG. 10B1, includes an assembly formed by two discrete membrane layers, the upper layer 341 and the lower layer 342, that are joined by gluing, welding, heat sealing, or other means along their two edge regions 344 as indicated by bond line 345. In another variation, illustrated schematically in FIG. 10B2 the assembly may be formed by a single membrane that has been folded in half with a fold 346 that is parallel to central lumen 343, wherein again the two regions parallel to and bordering central lumen 343 are joined together by gluing, welding, heat sealing, or other means. In some variations RF welding has been used. After the joining process is complete, the material in fold 346 may be cut away or otherwise removed or it left in place. In a third variation, shown schematically in FIG. 10B3 the assembly may be formed by a sleeve of membrane material, for example, fabricated by extrusion. Flattening the sleeve creates an assembly with the two desired layers. The central lumen can be formed by again joining together the two regions parallel to the lumen by gluing, welding, heat sealing, or other means and again, after the joining process is completed, the thusly created two folds 346 may be left in place or removed. Functionally these variations of the tunnel valve are equivalent and the choice of fabrication approach will be determined as an engineering decision.
In exemplary tunnel valves the layers can typically be between 0.001 inch or less and 0.1 inch thick. In one example a tunnel valve includes a single layer thickness of 001 inch. One suitable layer material is a 0.001″ thick, high tack polyurethane film.
In some variations the tunnel valve has a length (parallel to the central lumen) of between about 0.5 inches and 2.75 inches and a width of between 0.25 inches and 0.75 inches, although both larger and smaller tunnel valves are possible. The central lumen runs the full length of the tunnel valve and has a width, in one variation, of 0.095 inches, where the width is a design choice determined by the size of the particular fluid transport member 332 selected.
In additional variations, tunnel valves can be flexible, compressible and/or deformable. In additional variations, the lumen between the layers of the tunnel valve can be reopened after fluid transport member has been removed by the insertion and passage of a structure (e.g., a conduit or other fluid transport structure) through the closed tunnel valve.
As noted above, the tunnel valve allows for detachment of the remainder of the fluid transport member at any time, but typically once a sufficient amount of fluid is delivered to the device. Removal can occur via applying tension to a portion of the fluid transport member. Variations of the tunnel valve can employ permeable membranes, filter, or valves placed at the end of the tunnel valve to prevent dry hydrogel or other filler materials from entering the tunnel and affecting the ability of the tunnel valve to seal. In some embodiments, the membrane or filter may comprise a permeable fabric such as polyester, nylon, or cellulose. In other embodiments, a valve is placed at the end of tube comprised of a one-way duckbill or umbrella valve (available from MiniValve of Oldenzaal, Netherlands). Alternatively, or in addition, filler material 234 can be contained in an inner container which prevents the filler material from entering the tunnel valve and swelling upon infusion of liquid, thereby clogging the valve.
Referring to
In additional variations, as shown, for example, in
In some variations the tunnel valve comprises retaining elements to releasably hold the conduit in place throughout deployment of the device assembly.
A suture 1032, which may be inserted through either or both of interior section 1110A or exterior section 1110B, is designed to hold the conduit in the tunnel valve under a wide range of extractive force. As illustrated in the figure, suture 1032 is stitched through the two layers of the tunnel valve, simultaneously passing through conduit 1100. The suture is tied to itself on the exterior of tunnel valve 1110. The small punctures in conduit 1100 and tunnel valve 1110 through which the suture passes are too small to allow any significant loss of liquid filler.
Once the device assembly has assumed its deployment profile conduit 1100 must be withdrawn from tunnel valve 1110. Conduit 1100 is released from tunnel valve 1110 by the controlled, on-demand degradation of suture 1032. As is discussed above certain suture materials can be dissolved or structurally weakened by exposure to specific exogenous agents not normally in the gastric environments, or not in the gastric environment in high enough concentrations to degrade the suture during the deployment time period. For example, poly(caprolactone) [PCL] softens, melts, and weakens above a pre-determined temperature, TM. In some cases the pre-determined temperature can be designed to be greater than normal body temperature but lower than human's physiologic pain threshold. In such a case, a PCL suture can be degraded by infusing heated liquid (above TM) through conduit 1100 at the end of the deployment period or by having such liquid consumed orally.
In order to avoid over-filling the device assembly when the heated liquid is infused through the conduit the hot liquid infusion must start at after a pre-determined volume of un-heated liquid filler material has been infused, where the known capacity of the device assembly, the volume of fluid residual in the conduit, and the thermal capacity of the system are all incorporated into the determination. It should be noted that if the initial infusion of hot liquid fails to release the conduit by melting the suture, liquid can be withdrawn up the conduit to slightly reduce the volume of the device assembly and a second charge of hot liquid infused.
In another variation, as depicted in
Suture loop 1032 is installed during the manufacture of the device assembly and remains disposed in conduit 1110 during infusion of the liquid filler material. Conduit 1110 cannot easily be pulled out of tunnel valve 1110 while suture loop 1032 is in place. Once the device assembly has assumed its deployment profile, one end of suture loop 1032 may be released while the other end of the loop is pulled outwardly. When at least half the length of suture forming suture loop 1032 has been withdrawn from conduit 1100, the loop is known to be unthreaded from the eyelet hole(s). Freed from the eyelets, conduit 1100 can then be withdrawn from tunnel 1100.
In some embodiments suture loop 1032 of
Another variation of fluid transport member 1100 is illustrated in
In some variations the length of flaps 1028, 1026 is approximately 0.5 inches and tear line 1038 is disposed approximately 0.3125 inches from the exterior surface of the device.
As illustrated in the figure, conduit 1100 is attached to rip-off tab 1030 at spot location 1040 proximal to tear line 1038, where such attachment may be accomplished, for example, by gluing, melting, or ultrasonic welding. In some variations the attachment point, spot location 1040, is at least 0.0625 inches away from tear line 1038. In this variation conduit 1100 is detached from tunnel valve 1110 by pulling outwardly on conduit 1100 with enough force to separate rip-off tab 1030 from upper flap 1028 along tear line 1038. Although depicted examples show only a single rip-off tab 1030, additional variations include two or more rip-off tabs, one such tab on each of the two flaps, wherein conduit 1100 is attached to both tabs.
In some variations, as depicted in FIGS. 10H1-10H3, which show a cross sectional view of tunnel valve 1110 taken along line 10H-10H of FIG. 10B1, the deposition of a packing substance 1046 between the layers of the tunnel valve may enhance the sealing effectiveness of tunnel valve 1110. It will be noted that a packing substance, in this context, means a material that surrounds and fills, as in the “packing of a bearing”, and is not a substance used in packaging. In some variations packing substance 1046 is a fluid swellable material. In these variations the swellable material generally remains unswollen while the conduit 1100 is installed in the valve. After conduit 1100 removal, swellable material intercepts any liquid or semi-liquid filler material from the reservoir that migrates between the two layers of the nominally sealed valve. The swellable material swells in response to any liquid component in the intercepted filler material, thereby blocking further filler material migration through the valve.
The swellable material 1046 is typically superabsorbent poly(acrylic acid) hydrogel granules or superabsorbent poly(acrylic acid) hydrogel fibers. The swelling ratio of these substances (the mass of water absorbed for every gram of substance) is typically greater than 10.
In other variations the packing substance is a grease or grease-like lubricating material. The lubricating material is bio-compatible, being designed for use in the stomach, and is selected to have a high enough viscosity to remain in the central lumen for the expected duration of deployment. Typically the material is not soluble in water to any significant degree. In some variations the material is a high consistency dimethyl silicone grease.
In some variations packing material 1046 is inserted into central lumen 1020 prior to the insertion of conduit 1100 while in other variations the packing material is injected into the lumen and around the conduit after the conduit has been inserted through the lumen.
As illustrated schematically in the cross-sectional view in FIG.10H1, central lumen 1020 has a diameter over most of its length that closely matches the diameter of conduit 1100. This snug fit reduces the leakage of filler material during the filling process since filling material in the reservoir can enter the distal end 1110A1 of the lumen in the space around the exterior of the conduit. The dashed line A-A′ indicates the skin of the device assembly. Generally packing material 1046 is disposed toward the distal end of valve 1110 although in some variations it may be disposed towards the proximal end of the valve in the region approaching but not including the region of the unjoined flaps, as shown in the cross-sectional figure as upper flap 1028.
As depicted in the cross-sectional view schematically in FIG. 10H2, in some variations lumen 1020 is tapered in one or more regions 1042, 1044. The region between the two tapered regions forms a pocket into which the packing material may be disposed. In embodiments with only one tapered region the region will typically be disposed near distal end 1110A1 and the packing material 1046 will be disposed to the proximal side of the tapered region. Tapered regions 1042 and 1044, may have a design diameter so that the conduit 1100 fits snugly through the tapered regions and less snugly in the untapered regions. That is, the diameter of the tapered regions is substantially equal to the diameter of the conduit. The tapered region can then prevent most of the liquid filler from reaching the packing material while conduit 1100 is in place, inhibiting any swelling of a swellable packing material or any migration of the packing material out of the lumen during storage. This variation is particularly suitable for a swellable packing material, which in many variations comprises dry, flowable granules. Once the conduit is removed any fluid that follows the conduit up the lumen is intercepted by the swellable material which then swells and blocks the flow of additional fluid.
Another variation is illustrated schematically in the cross-sectional view in FIG. 10H3. In this variation lumen 1020 comprises an enlargement region or pocket 1047 into which an extra volume of packing substance 1046 may be inserted. This variation is similar in function to the variation illustrated in FIG. 10H2. It may be advantageous compared to that variation in that the diameter of the lumen may be snugly fit to the catheter over a longer length than is possible in the variation of FIG. 10H2, thus providing better containment of the packing material in the pocket and greater resistance to filling fluid flow out of the reservoir.
In some embodiments the seal of valve 1110 may be enhanced mechanically, as illustrated in
Device 2000 further comprises a spring 2020 or similar energy storage element. Loops 2010, hinge axle 2015 and spring 2020 are configured to allow spring 2020 to drive loops 2010 into generally adjacent alignment by rotating one or both loops around hinge axle 2015, as indicated by arrow A in
During deployment, conduit 1100 is disposed within orifice 1020, typically extending through substantially the entire length of elongate portion 1022. As previously noted, in some embodiments conduit 1100 extends beyond the end of orifice 1020, as illustrated in
Elongate portion 1022 is, by design, stiff enough to hold closure device 2000 in its open-flat configuration during deployment. It will be noted that elongate portion 1022 is stiffened during deployment by the presence of conduit 1100 since, as described herein, elongate portion 1022 is fabricated with two thin layers of a membrane-like material designed to collapse upon themselves while conduit 1100 must be rigid enough to provide an open fluid channel from a patient's mouth to his stomach.
After deployment, conduit 1100 is withdrawn from orifice 1020. Once the end of conduit 1100 passes the crossbar of loop 2010A, elongate portion 1022 is no longer stiff enough to retain loop 2010A in its open-flat configuration. Loop 2010A is rotated by torsion spring 2020 in the direction of arrow A, wrapping the distal end of elongate portion 1022 around hinge axle 2015 in the process. Loop 2010A continues rotating until it rests against loop 2010B, simultaneously pressing and sealing the doubled over elongate portion 1022.
In an alternative exemplary configuration, illustrated in side-view in
In another embodiment, not illustrated, an elastic ring provides the mechanical assistance for enhancing the seal of valve 1110. The ring is disposed around on elongate portion 1022 of valve 1110. The ring's material properties and dimensions are selected to substantially seal the tunnel valve when the valve does not contain conduit 1100. However, when conduit 1100 is positioned within the tunnel valve, the rigidity of the conduit resists the sealing force of the elastic ring. The elastic ring may be composed of any elastomeric material that is known to be biocompatible. Examples include silicone, polyurethane, and latex.
As was described above, in some variations of a tunnel valve the two layers of the valve, upper layer 341 and lower layer 342, are fabricated as integral parts of the upper material surface 1014 and lower material surface 1016 of the device. A device having integral tunnel valve layers shown in mid-fabrication in the plan view of
The two sheets are then joined around the periphery of the hemi-ellipsoids to seal them together along sealed seam 1004. One method for sealing the device 1000 comprises an ultrasonic or radio-frequency (RF) weld. In the example shown in
After joining the device is trimmed to remove the excess material along a trim line 1006. Either before or after joining an access aperture 1410 is opened in one of the material surfaces. Typically this aperture is circular although it appears distorted in
Fabrication Methods
As described above, one method for fabricating balloon-type devices from thin film-like polymeric working material comprises the steps of forming two device sections, for example by thermoforming, and subsequently joining the two sections together by a peripheral weld that creates an external seam. In many cases the device is inverted to convert the external seam into an internal seam, as is often done in clothing manufacture. In some variations of the method a backing layer, also a polymeric material, is left attached to the working material until after the joining step. In other variations of the method, balloon-type devices may be fabricated in one seamless piece by dip molding or blow molding.
Thermoforming
In some thermoforming variations of the fabrication method, each of the two device sections is fabricated from a working layer 1510 comprising a thin film of polymeric material such as polyurethane (PU).as illustrated in
The PU thin film material may be extrusion cast. In a cast film extrusion process molten polymer travels through a flat die system comprising a die and feedblock (if the process requires co-extrusion of, for example, a polymeric backing layer). The thin film is extruded through a slit onto a chilled, highly polished turning roll, where it is quenched from one side. The speed of the roller controls the draw ratio and final film thickness. The film is then sent to a second roller for cooling on the other side. Finally it passes through a system of rollers and is wound onto a roll.
Alternatively, the PU thin film material may be blow extruded. Blown film extrusion is a technology that is the most common method to make plastic films. The process involves extruding a tube of molten polymer through a circular die and inflating to several times its initial diameter to form a thin film bubble. After cooling, this bubble is then collapsed and can be slit to be used as a lay-flat film. As with cast film extrusion, co-extrusion is possible. In particular, a three-layer sandwich of PU with two PE backing layers can be co-extruded with this process.
In one exemplary embodiment, shown in
In one variation of the method, the flat sheets of thin film material are formed into a device sections by the thermoforming process. As shown in
As shown in
As shown in
In another variation of the fabrication method, pressure thermoforming may be used, wherein polymeric sheet 1910 is pushed into mold 1920 by an excess pressure 1940 on the side of polymeric sheet 1910 away from mold 1920. As illustrated in
As shown in
As illustrated in
The final step of this part of this variation of the fabrication method, not illustrated, is removal of material 1910 from mold 1920 after material 1910 has cooled enough to hold its shape. This cooled material is one device section.
In both variations, vacuum thermoforming and pressure thermoforming, the polymeric sheet is forced to conform to the mold by a differential gas pressure, ΔP, between the “mold side” of the sheet and the “non-mold side” of the sheet, wherein the difference between vacuum and pressure thermoforming is how differential pressure ΔP is generated. A known benefit of vacuum thermoforming is that polymeric sheet 1910 forms its own seal against mold 1920 so the higher, one atmospheric pressure 1935 pushes polymeric sheet 1910 against the mold, while a known benefit of pressure thermoforming is that polymeric sheet 1910 can be pressed down by a greater-than-one-atmosphere ΔP more firmly against the mold, causing it to better match small details and short radius bends.
As is known to one of skill in the art, there are many other variations to the thermoforming art, each of which each of which comprises at least heating a thermoplastic material and preparing a mold to whose shape the material is made to conform. Indeed, for certain unique finished shapes even the mold may be superfluous. In general, any known thermoforming technique may be used to form the device sections. In particular, the inventors have determined for certain variations of a gastric balloon the use of a pressure-less, draping thermoform approach may be useful. In this approach, the heated material 1910 is draped or stretched over a suitably shaped convex mold, with gravity and residual material elasticity conforming the material at least approximately to the shape of the mold. Typically, but not necessarily the mold in this fabrication approach is porous to prevent air bubble entrapment. Thermoforming with backing layers
In accordance with standard practice, and as is illustrated in
It has been discovered that the thermoforming operation can be performed on the polymeric material in all three variations—one, two, and three layers. However, to perform the later, joining, step, discussed below, the material must have one surface of the working layer 1510, say PU, exposed on each device section for the joining process to succeed. Thus, if the material comprises two backing layers 1522A, 1522B disposed on opposite surfaces of working layer 1510, one of the two backing layers, say layer 1522A, may optionally be removed from the working layer, as was illustrated in
The next step in the fabrication method is forming the film material into device sections, as illustrated in
As illustrated in cross-section in
As illustrated in
It may be noted that in other variations of the method the mold is convex. When a convex mold is employed the orientations of the co-extruded material for making the concave and convex device sections are reversed. That is, for example, a thermoformed item fabricated on a convex mold with the backing layer in direct contact with the gaseously porous block is referred to as a convex section.
In other variations of the method the mold comprises a dual mold having both a concavity 1720 and a convexity 1722 displaced a convenient working distance apart.
In another variation of the method the second backing layer 1522A is left in place during thermoforming, in which case there is only one “orientation” since both sides of working layer 1510 are covered by a backing layer 1522.
In all variations of this method the working layer is thermoformed with one or two backing layers attached. Successful thermoforming requires that the HDT properties of both the working layer and the backing layer(s) be similar so that one layer does not melt when the other layer is at the HDT.
Returning to
A device is fabricated by joining two device sections. Optionally, an access hole may be cut in at least one of the two device sections to allow the joined sections to be inverted, that is, for the joined sections to be turned inside out. In some variations of the device the access hole is generally circular with a diameter on the order of one quarter to one half the diameter of the hemi-ellipsoid. In one embodiment, the access hole is approximately 25 millimeters in diameter. In some variations of the method a die cutter is used to cut the access hole.
The cross-sectional illustration in
If thermoforming has been performed using the dual mold illustrated in
In some variations the device sections may not be rotationally symmetric or in the case of two concave sections, as was illustrated in
It will be noted that the optional access hole, not illustrated, is typically, but not necessarily, cut into a device section before nesting and joining.
After alignment, the two device sections are joined. In one variation they are joined by RF welding while in other variations they can be joined by any of the well-known means of joining two layers of polyurethane such as those techniques described in http://www.mddionline.com/article/polyurethane-thin-film-welding-medical-device-applications. RF welding is a form of dielectric heating. As such, the materials to be joined by RF welding must be poor conductors of electricity, since a good conductor would act as a short circuit, weakening the field near the conductor. The PU working layer is amenable to RF welding whereas the PE backing layer is not responsive to the process, allowing the method to keep the backing layer in place during RF welding.
The RF process generates radio-wave power, which causes molecules within the material to be agitated. As a result, heat is generated within the material, allowing adjacent plastic materials to melt and exchange molecules, thereby bonding the materials. When the power to the RF-energy generator is shut off, the melted plastic resolidifies, resulting in a uniform weld that is as strong or stronger than the materials being bonded together.
An electrode, or die, machined in the shape of the region to be joined is used to apply power to the device sections. In the present process, the region to be joined is the flange around the formed body of the device sections. As shown in
In some variations, optional device subcomponents, for example, tunnel valve 1110, are sealed into the seam 1004. In some instances, these subcomponents are disposed into an opening left in seam 1004 during the joining step and sealed therein in a secondary joining operation performed after the device has been inverted, as was described above with reference to
In other variations these optional device subcomponents may be designed to be an integral part of the device section(s), as was discussed above with reference to
When the seam 1004 is sealed with the RF welding process, these parallel valve seams are sealed as well. In other variations of the method in which RF welding is not used for joining the device sections together, equivalent modifications to the joining process can be made to incorporate the optional device subcomponents.
After the joining step is complete the device is trimmed along a trim line to remove excess material around the external seam, that is, the material outside the designed, sealed flange/seam.
Additionally, in some variations of the method, after the joining step is complete and either before or after the excess material around external seam 1004 is removed, any remaining backing layer material is removed. In variations in which the device is completed at this step the backing layer may be left in place for protective purposes until a convenient time but in no case later than deployment in a patient. In variations of the device in which an access hole 1017 has been cut in one or both device sections, the device may be inverted by turning the device inside out through access hole 1017. In this variation the backing layer must be removed before inversion. Inverting the device converts external seam 1004, which may irritate bodily organs when the temporary implant device is deployed, into an internal seam whereby the device presents a smooth exterior to the bodily tissue to which it comes in contact.
With the device inverted, a patch of material sized and shaped to seal access hole 1017 is joined to the device using RF welding, gluing or other means of joining. In all variations, appropriate shielding/isolating steps must be employed to prevent the upper and lower device sections from accidentally being joined the at the location of the access hole along with the access hole patch.
The present application is a non-provisional of U.S. Provisional application No. 62/528,942 filed Jul. 5, 2017, entitled METHOD OF FABRICATION FOR DEVICES FOR DEPLOYING AND RELEASING A TEMPORARY IMPLANT WITHIN THE BODY, and U.S. Provisional application No. 62/492,773 filed May 1, 2017, entitled METHOD OF FABRICATION FOR DEVICES FOR DEPLOYING AND RELEASING A TEMPORARY IMPLANT WITHIN THE BODY, the entirety of both of which are herein incorporated by reference. This application is also related to PCT publication WO2017136840 filed Feb. 6, 2017, the entirety of which is incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62492773 | May 2017 | US | |
| 62528942 | Jul 2017 | US |
