Abstract
A gastric constriction device comprises a sheet extending over part of the wall of the stomach. Five bands extend around the stomach to fix the sheet in position relative to the stomach. The lower two bands extend from the first side of the sheet around the stomach only partially towards the second side. These lower two bands are not fixed to the second side. This arrangement results in an unconstricted portion of the stomach. In this manner, the device restricts expansion of the majority of the stomach wall while facilitating expansion of this unconstricted portion. The unconstricted portion is therefore free to expand or bulge outwardly upon ingestion. This expansion may trigger the feeling of satiation due to the presence of the vagal nerves in this portion of the stomach.
Claims
1. A method of treating obesity comprising the steps of: applying a collapsing force to a stomach to at least partially collapse the stomach from a normal volume to a reduced volume to constrict the volume of the stomach; positioning a gastric constriction device relative to an external wall of the stomach; releasing the collapsing force; applying a constricting force to the stomach to constrict the volume of the stomach via the gastric constriction device; and stimulating gastric nerves.
2. The method of claim 1, wherein the gastric constriction device comprises a polymer material.
3. The method of claim 2, wherein the polymer material is a polymer sheet.
4. The method of claim 1, wherein a constricting property of the gastric constriction device varies over at least part of the gastric constriction device.
5. The method of claim 2, wherein the polymer material is configured to extend substantially circumferentially partially around the stomach.
6. The method of claim 1, wherein the gastric constriction device comprises a bio-absorbable polymer material for absorption of at least some of the material into a stomach wall over time.
7. The method of claim 6, wherein the gastric constriction device is configured for absorption of substantially all of the gastric constriction device into the stomach wall over time.
8. The method of claim 1, wherein applying a collapsing force to the stomach comprises inserting a collapsing device at least partially into an interior of the stomach to at least partially collapse the stomach from the normal volume to the reduced volume.
9. The method of claim 8, wherein the collapsing device comprises a suction device to at least partially collapse the stomach by applying suction to the interior of the stomach.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 is a perspective view of a prior art gastric banding device;
(2) FIG. 2 is a perspective view of a gastric constriction device according to the invention;
(3) FIG. 3 is a perspective view of the device of FIG. 2 extending around a stomach;
(4) FIG. 4 is a perspective view of a collapsing device according to the invention;
(5) FIG. 5 is a perspective view of an unrestricted stomach;
(6) FIGS. 6 to 8 are perspective views illustrating constricting the volume of the stomach of FIG. 5 using the gastric constriction device of FIG. 2 and the collapsing device of FIG. 4;
(7) FIG. 9 is a view along line IX-IX in FIG. 7;
(8) FIG. 10 is a perspective view of another gastric constriction device according to the invention in a strip configuration restricting the stomach;
(9) FIG. 11 is a perspective view of a further gastric constriction device according to the invention extending around a stomach;
(10) FIG. 12 is a perspective view of a loop band of the device of FIG. 11 in a release configuration;
(11) FIG. 13 is a perspective view of the loop band of FIG. 12 in a fixed configuration;
(12) FIGS. 14 and 15 are perspective views similar to FIGS. 12 and 13 of a loop band of another gastric constriction device according to the invention;
(13) FIG. 16 is a plan view of an end of the loop band of FIG. 14;
(14) FIG. 17 is a perspective view of a tool suitable for use with the loop band of FIGS. 14 to 16;
(15) FIG. 18 is a perspective view similar to FIG. 12 of a loop band of another gastric constriction device according to the invention;
(16) FIG. 19 is a plan view of an end of the loop band of FIG. 18;
(17) FIG. 20 is a perspective view of another gastric constriction device according to the invention extending over the wall of a stomach to restrict the stomach;
(18) FIG. 21 is a view along line XXI-XXI in FIG. 20;
(19) FIGS. 22 and 23 are perspective views illustrating collapsing the volume of a stomach using the gastric constriction device of FIG. 20 and another collapsing device according to the invention;
(20) FIG. 24 is a view along line XXIV-XXIV in FIG. 23;
(21) FIGS. 25(a) and 25(b) are perspective views of a further gastric constriction device according to the invention;
(22) FIG. 26 is a perspective view of the device of FIG. 25 extending over the wall of a stomach;
(23) FIG. 27 is a plan view of another gastric constriction device according to the invention;
(24) FIG. 28 is a perspective view of the device of FIG. 27 extending over the wall of a stomach;
(25) FIG. 29 is a perspective view of another gastric constriction device according to the invention;
(26) FIGS. 30 and 31 are perspective views illustrating constricting the volume of a stomach using a loop band according to the invention and the device of FIG. 29;
(27) FIG. 32 is a view along line XXXII-XXXII in FIG. 31;
(28) FIGS. 33 and 34 are perspective views of the gastric harness implant of FIG. 29 used with a gastric banding device;
(29) FIG. 35 is a view along line XXXV-XXXV in FIG. 34;
(30) FIG. 36 is a plan view of another gastric constriction device according to the invention in a strip configuration with attachment points;
(31) FIG. 37 is a perspective view of the device of FIG. 36;
(32) FIG. 38 is a perspective view of a further gastric constriction device according to the invention extending around a stomach;
(33) FIG. 39 is a perspective view of a material that can be machined to produce a gastric constriction device according to the invention;
(34) FIG. 40 is a perspective view of a laminated film structure showing layers of biocompatible films bonded together;
(35) FIGS. 41 and 42 relate to an implant designated Mesh2E, where FIG. 41 is a diagram of an exemplary pore, and FIG. 42 is a display of various measured parameters within Mesh2E and the equations used to calculate the surface area;
(36) FIG. 43 is a diagram of an exemplary pore structure for Mesh2E;
(37) FIG. 44 is a micrograph of Mesh2E;
(38) FIG. 45 is a side view of a material of another gastric constriction device according to the invention;
(39) FIG. 46 is a side view of a first layer of the material of FIG. 45;
(40) FIG. 47 is a plan view of the first layer of FIG. 46;
(41) FIG. 48 is an enlarged, plan view of a part of the first layer of FIG. 47;
(42) FIGS. 49 to 51 are views similar to FIGS. 46 to 48 of a second layer of the material of FIG. 45;
(43) FIGS. 52 and 53 are plan views of materials of further gastric constriction devices according to the invention; and
(44) FIG. 54 is a flow chart illustrating some of the steps in a method of producing a gastric constriction device according to the invention.
SELECTED REFERENCE NUMERALS IN DRAWINGS
(45) 10 gastric banding device 12 biocompatible film 14 laminated film structure 16 cell pattern 18 radius 20 cell pattern structure 22 machined film 24 unrestricted stomach 26 gastric harness implant 28 attachment points 32 strip configuration 34 gastric band 36 gastric pouch
DETAILED DESCRIPTION
(46) FIG. 1 illustrates a prior art gastric banding device 10 that can be used to perform gastric banding procedures.
(47) Referring to FIG. 2 there is illustrated a gastric constriction device 100 according to the invention. The device 100 comprises a substantially elongate spiral band 101 which may be extended around a stomach 24 in a spiral to constrict the volume of the stomach 24, as illustrated in FIG. 3.
(48) A fixation arrangement is provided at each end of the band 101. In this case, each fixation arrangement is provided in the form of an arrow-head shaped member 103 at the end of the band 101, which may be received in one of a plurality of corresponding slots 104 in the band 101. As illustrated in FIG. 2, the slots 104 are located spaced a distance from the end of the band 101. The plurality of slots 104 enable a degree of adjustment of the constriction force to be achieved.
(49) It has been found that the spiral wrap of the band 101 may be positioned around the blood vessels of the stomach wall in such an arrangement such as to preserve blood flow.
(50) FIG. 2 illustrates the gastric harness strip 101 in spiral wrap form. The strip material can be preformed with three-dimensional properties and may be made from a shape memory material. The strip 101 can also form bands at the top and bottom for securement near the oesophagus and pylorus. Slits 104 in the strip 101 can be used to create bands. The circular bands prevent slippage and provide a smooth interface with the stomach 24 to minimise the risk of erosion. The central portion is wrapped around the stomach 24 in circular fashion and is spaced such that the stomach 24 will not distend through the spacings when food is ingested.
(51) Multiple slits 104 in the strip 101 can be provided to adjust the diameter of the band. This permits a fit that prevents slippage while minimising the risk of erosion if the band is placed too tightly around the stomach 24. A tapered point 103 on the strip 101 facilitates placement through the slit 104. Holes 300 in the tapered point 103 permit the use of instruments to facilitate grasping. The holes 300 also permit securement if a suture or a staple is used. The width of the tapered securement point 103 is wider than the slit 104 to create a mechanical lock.
(52) FIG. 4 illustrates a suction device 105 according to the invention suitable for use with the gastric constriction device 100 to constrict the volume of the stomach 24. Together the suction device 105 and the gastric constriction device 100 provide a gastric constriction apparatus.
(53) The suction device 105 includes a plurality of openings 106 along the length of the suction device 105 for applying suction to the interior of the stomach 24.
(54) With reference to FIGS. 5 to 9, in use the suction device 105 is inserted through the oesophagus 107, into the interior of the unrestricted stomach 24, until the distal tip 108 of the suction device 105 reaches the pylorus 109 (FIG. 6). The suction device 105 engages the tissue wall at the oesophagus 107 and at the pylorus 109 to effect a seal.
(55) Suction is then applied to the interior of the stomach 24 using the suction device 105. This suction exerts a collapsing force on the stomach 24, and causes the stomach 24 to partially collapse from the normal volume (FIGS. 5 and 6) to a reduced volume (FIGS. 7 and 8). A typical normal volume for the stomach is 750 cc, and a typical reduced volume is 100 cc.
(56) The spiral band 101 is positioned relative to the partially collapsed stomach 24 extending around the stomach 24 in a spiral, and the spiral band 101 is fixed in position by inserting each arrow-head shaped member 103 into a corresponding slot 104 (FIG. 7).
(57) The suction may then be released to release the collapsing force exerted on the stomach 24, and the suction device 105 is removed from the stomach 24 and oesophagus 107. The gastric constriction device 100 remains fixed in position around the stomach 24 constricting the volume of the stomach 24 (FIG. 8).
(58) FIGS. 6 to 8 illustrate the gastric harness with calibrated vacuum assisted deployment. A fixed volume/diameter gastric tube 105 is placed inside the stomach 24 with or without perforations (illustrated with perforations). A means for applying a vacuum is also present. Perforations 106 are positioned inside the stomach 24 and a seal is created at the oesophagus 107 and pylorus 109. The gastric tube 105 may have fixed compliance and volume to replicate the pressure and volume relationship experienced when food is ingested. The gastric harness implant 100 is placed around the stomach 24 with the gastric tube 105 in position. Folds in the stomach wall are created as the surface area in the outer wall is reduced. The gastric harness implant 100 remains in position and the gastric tube 105 is removed (FIG. 8).
(59) In FIG. 10 there is illustrated another gastric constriction device 110 according to the invention, which is similar to the device 100 of FIG. 2, and similar elements in FIG. 10 are assigned the same reference numerals.
(60) In this case the spiral band 101 extends around the stomach 24 in a spiral with each turn of the spiral partially overlapping an adjacent spiral turn.
(61) FIG. 10 is a perspective view of a gastric harness implant 110 in a strip configuration 101 which in this case is wrapped around the stomach 24. The implant 110 may extend from the oesophagus 107 beyond the pylorus 109 to the small intestine. The strip configuration 101 may be passed around the stomach 24 and secured at the edges along attachment points 28 with sutures or staples.
(62) FIGS. 11 to 13 illustrate another gastric constriction device 120 according to the invention, which is similar to the device 100 of FIG. 2, and similar elements in FIGS. 11 to 13 are assigned the same reference numerals.
(63) In this case the device 120 comprises a plurality of loop bands 121. Each band 121 is suitable for being extended around the stomach 24 in a loop. By extending the plurality of loop bands 121 around the stomach 24 at a plurality of regions spaced along the stomach 24, the device 120 constricts the volume of the stomach 24, as illustrated in FIG. 11.
(64) FIGS. 11 to 13 illustrate the gastric harness implant formed from individual bands. The gastric harness 120 can be formed from individual bands 121 or strips of material. Each individual band 121 has an attachment point for variable adjustment. The strips 121 can be placed from the oesophagus 107 to the pylorus 109. The gastric bands 121 provide a smooth interface with the stomach 24. The bands 121 are spaced such that the stomach 24 will not distend through the openings when food is ingested. The individual gastric bands 121 have preformed curves and variable adjustment means with spaced slits 104 to accommodate the taper point 103 (FIGS. 12 and 13).
(65) Alternative fixing arrangements for fixing the loop bands 121 in position extending around the stomach 24 are illustrated in FIGS. 14 to 19.
(66) The preformed individual bands 121 have two different attachment means. Each has a hole 300 for securement with a suture, staple, or other attachment means. A tool 122 is illustrated for moving the tapered point 103 through the slit 104 (FIGS. 14 to 16), and for moving the ratchet headpiece 123 through the corresponding slot 104.
(67) Referring to FIGS. 20 and 21 there is illustrated another gastric constriction device 130 according to the invention, which is similar to the device 100 of FIG. 2, and similar elements in FIGS. 20 and 21 are assigned the same reference numerals.
(68) In this case the device 130 comprises a continuous sheet 131 for extending over the entire wall of the stomach 24. In this manner, the sheet 131 may enclose the stomach 24 and thereby constrict the volume of the stomach 24.
(69) FIG. 20 is a perspective view of a gastric harness implant 26 restricting the volume of the stomach 24. In another case the gastric harness implant 26 may extend from the oesophagus 107 beyond the pylorus 109 to the small intestine. The implant 26 may be of a film material such as those described below, for example the mesh 2E material.
(70) In FIGS. 22 and 23, there is illustrated another suction device 140 according to the invention, which is similar to the suction device 105 of FIG. 4, and similar elements in FIGS. 22 and 23 are assigned the same reference numerals.
(71) In this case the suction device 105 comprises a distal balloon member 142 and a proximal balloon member 141. In use, the balloon members 141, 142 are inflatable to engage the tissue wall to effect a seal prior to suction being applied.
(72) FIGS. 25 and 26 illustrate a further gastric constriction device 150 according to the invention, which is similar to the device 130 of FIGS. 20 and 21, and similar elements in FIGS. 25 and 26 are assigned the same reference numerals.
(73) In this case, the sheet 131 is substantially shell-shaped, and extends over only part of the wall of the stomach 24. Five bands 151 extend from a first side 152 of the sheet 131 partially around the stomach 24 to a second side 153 of the sheet 131. In this manner, the bands 151 fix the sheet 131 in position extending over part of the wall of the stomach 24.
(74) The bands 151 are releasably fixed to the second side 153 of the sheet 131 by means of the arrow-head member 103 and corresponding slots 104 arrangement.
(75) FIGS. 25 and 26 illustrate the preformed gastric harness. The preformed gastric harness implant 150 is designed to engage the outer surface of the stomach 24 to reduce tension when food is ingested. The shape of the implant 150 can be adjusted such that the lesser and lower curvatures of the stomach 24 can be preferentially reduced to accommodate less volume when food is ingested. The three dimensional properties can facilitate sizing and placement. The implant 150 is curved to adjust to the shape of the stomach 24. Bands 151 are incorporated to wrap around the outer surface of the stomach 24. The spacing between bands 151 prevents stomach expansion when food is ingested. Slits 104 are placed in the implant 150 to accept the bands 151 with a tapered point 103, which permits instrument manipulation and placement. The tapered point 103 also has a hole 300 for accepting a suture, or staple for securing the implant 150. The implant 150 is positioned and the bands 151 are adjusted using the slits 104 in the implant 150 to adjust the tension.
(76) In FIGS. 27 and 28, there is illustrated another gastric constriction device 160 according to the invention, which is similar to the device 150 of FIGS. 25 and 26, and similar elements in FIGS. 27 and 28 are assigned the same reference numerals.
(77) In this case the lower two bands 151 extend from the first side 152 of the sheet 131 around the stomach 24 only partially towards the second side 153. These lower two bands 151 are not fixed to the second side 153. This arrangement results in an unconstricted portion of the stomach 161. In this manner, the device 160 restricts expansion of the majority of the stomach wall while facilitating expansion of this unconstricted portion 161.
(78) The unconstricted portion 161 is therefore free to expand or bulge outwardly upon ingestion. This expansion may trigger the feeling of satiation due to the presence of the vagal nerves in this portion 161 of the stomach 24.
(79) FIGS. 27 and 28 illustrate the gastric harness implant to modulate stomach expansion. A preformed implant 160 is designed such that areas of the stomach 24 can preferentially expand more under pressure when food is ingested. Placing the more elastic zones adjacent to the nerves that are responsible for signalling when stretch/tension receptors are activated may create the feeling of satiety. Preferential expansion is created in the area where more elastic zones are present or where the implant material is not present to constrain the stomach 24. Vagal nerves are more readily activated. An area for accepting a gastric pacing device may also be present. This may improve the efficacy of the concept.
(80) Referring to FIG. 29 there is illustrated another gastric constriction device 170 according to the invention, which is similar to the device 130 of FIGS. 20 and 21, and similar elements in FIG. 29 are assigned the same reference numerals.
(81) In this case, the sheet 131 extends around the full circumference of the stomach 24, but extends distally over only part of the wall of the stomach 24 from the oesophagus 107 approximately to of the distance towards the pylorus 109.
(82) In use, a laparoscopic band 171 is extended around the stomach 24 (FIG. 30), and the device 170 is then extended around and along the stomach 24 with the band 171 located between the sheet 131 and the stomach wall (FIGS. 31 and 32).
(83) To fix the sheet 131 in position extending over the wall of the stomach 24, a first region 172 of the sheet 131 is fixed directly to a second region 173 of the sheet 131.
(84) FIGS. 29 to 32 illustrate the gastric harness implant used in conjunction with laparoscopic banding. The gastric harness 170 is used to prevent expansion of the fixed volume pouch created during laparoscopic banding. The gastric harness 170 conforms generally to the outside surface of the stomach 24 when the pouch is created. Holes 175 are present for accepting sutures and/or staples. The gastric harness 170 can be flared to minimise the risk of erosion and irritation. The cross section (FIG. 32) demonstrates the interface between the stomach pouch and gastric harness 170.
(85) As illustrated in FIGS. 33 to 35, the laparoscopic band 171 may alternatively be extended around the sheet 131, after the sheet 131 has been extended around and along the stomach 24. In this case, the sheet 131 is located between the band 171 and the stomach wall.
(86) The arrangement of FIGS. 29 to 32 is particularly advantageous. The technique used to insert the band 171 in FIGS. 29 to 32 is a simple, easy to practise technique. In particular, this technique would be compatible with many alternative banding devices.
(87) FIGS. 33 and 34 are perspective views of a gastric harness implant 170 forming a gastric pouch 36. A gastric band 34 is provided. The band 34 may be a part of the implant 170 or separate from it. The gastric harness implant 170 in this configuration prevents the gastric pouch 36 from dilatation.
(88) In FIGS. 36 and 37 there is illustrated another gastric constriction device 180 according to the invention, which is similar to the device 120 of FIG. 11, and similar elements in FIGS. 36 and 37 are assigned the same reference numerals.
(89) FIGS. 36 and 37 are perspective views of an implant material in a strip configuration 32 with attachment points 28.
(90) FIGS. 36 and 37 illustrate the gastric harness strip with attachments. A strip 121 is disclosed for winding around the stomach 24. The strip 121 is intended to be placed laparoscopically using minimally invasive techniques and instrumentation. The strip 121 has attachment points 28 for accepting sutures, staples, or other securement means. The attachment points 28 are rounded and are in the form of eyelets to minimise the risk of tissue reaction and erosion. Cell openings are present for tissue in-growth and fixation to the stomach wall.
(91) In the embodiment of FIG. 38, a plurality of bands 190 are provided extending around the stomach 24 circumferentially and longitudinally along the stomach 24 for constricting the volume of the stomach 24.
(92) FIG. 39 is a perspective view of a material that can be used to produce a gastric constriction device of the present invention. The material may be machined to produce a nonwoven gastric harness implant. The material illustrated in FIG. 39 is a perspective view of a nonwoven biocompatible film 12. The film 12 has known or discernible dimensions (width, length, and thickness), which can be modified or left intact in the manufacture of a gastric harness implant. In this case the film 12 is a single-layer, smooth-edged film.
(93) As shown in FIG. 40, the film 12 can be laminated to produce a film 14, which can also be used, with or without further modification, to manufacture the implants of the present invention. Multiple layers of biocompatible film 12 can be added together to improve the mechanical properties (e.g., tear resistance and burst strength) of the implant. For example, a first film 12 can be bonded to a second film 12. The bonding may be a thermal bond using hydraulic presses such as those manufactured by OEM Press Systems (Orange, Calif., USA).
(94) Biocompatible materials useful in film 12 or film 14 can include non-absorbable polymers such as polypropylene, polyethylene, polyethylene terephthalate, polytetrafluoroethylene, polyaryletherketone, nylon, fluorinated ethylene propylene, polybutester, and silicone, or copolymers thereof (e.g., a copolymer of polypropylene and polyethylene); absorbable polymers such as polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone, and polyhydroxyalkanoate, or copolymers thereof (e.g., a copolymer of PGA and PLA); or tissue based materials (e.g., collagen or other biological material or tissue obtained from the patient who is to receive the implant or obtained from another person.) The polymers can be of the D-isoform, the L-isoform, or a mixture of both. An example of a biocompatible film 12 suitable for producing the laminated film structure 14 is expanded polytetrafluoroethylene.
(95) In the case of a laminate 14, the various layers may be of the same or different materials. For example, in the case of an absorbable material, the material of the layers may be selected to have varying rates of absorption.
(96) FIGS. 41 and 42 relate to an implant designated Mesh2E. Referring to FIG. 41, a sinusoidal cell pattern 16 has been designed with radius 18. The properties of the cell pattern 16 are described in detail in FIG. 42.
(97) FIG. 43 relates to a cell pattern structure 20 for cell pattern 16. The cell pattern structure 20 has been constructed using computer-aided design.
(98) FIG. 44 is a micrograph of a machined film 22. The machined film 22 is in this case constructed using a die-punching tool machined to cell pattern structure 20. The machined film 22 has porosity, which can impart and support tissue ingrowth on high strength thin film substrates. A radius 18 may be applied to each cell pattern 16 corner to improve tear strength. Manufacturing methods to impart cell pattern 16 include, but are not limited to, laser machining, die punching, water jet cutting, and chemical etching. The lasers preferred for creating smooth edges on plastic films include, but are not limited to, CO.sub.2, diode ultraviolet, or excimer lasers. An implant having cell pattern 16 is expected to confer benefit to a patient in which it is implanted because of the substantially smooth edges of cell pattern 16. Openings between 10 and 10,000 microns can be created in the film 22 with the geometry cell pattern 16. An opening of about 2000 microns creates an implant with adequate porosity for tissue ingrowth and good mechanical properties.
(99) In FIGS. 45 to 51 there is illustrated a bio-absorbable material 200 suitable for use in forming the gastric constriction device of the invention. The bio-absorbable nature of the material 200 facilitates absorption of the device into the stomach wall over time.
(100) As illustrated in FIG. 45, the material 200 has a laminate construction. Both the first layer 201 and the second layer 202 of the material 200 are porous to promote tissue in-growth. The first layer 201 has a higher pore density and smaller pore size than the second layer 202 (FIGS. 48 and 51). In this manner, the first layer 201 has a higher absorption rate and permits faster tissue remodelling than the second layer 202.
(101) In use, the second layer 202 is located closer to the wall of the stomach 24 than the first layer 201.
(102) FIGS. 45 to 51 illustrate the three-dimensional gastric harness scaffold. A scaffold 200 comprising layers 201, 202 of porous material is assembled. One layer 202 may have larger cells/pores with wider and/or thicker struts with longer degradation times. One layer may be composed of a material with a longer degradation time. The pores may be formed before the layers 201, 202 are attached to one another. The pores may have different dimensions and compositions, which vary the healing and degradation characteristics. Tissue will grow from the outside in and remodel at a controlled rate, which may permanently alter the volume potential of the stomach 24 due to the mechanical properties of the gastric wall after tissue has been deposited.
(103) Referring to FIG. 52 there is illustrated another bio-absorbable material 210 suitable for use in forming the gastric constriction device of the invention.
(104) In this case the material 210 comprises an anti-adhesion coating along at least part of the surface of the material 210.
(105) In FIG. 53 there is illustrated a further bio-absorbable material 220 suitable for use in forming the gastric constriction device of the invention.
(106) In this case the material 220 comprises an anti-adhesion filler 221 filling at least some of the pores.
(107) FIGS. 52 and 53 illustrate the gastric harness with adhesion prevention material. The adhesion prevention material fills the cells and/or coats the porous material used to construct the gastric harness implant. The adhesion prevention material is absorbed at a controlled rate or stays on the material permanently to prevent unwanted adhesions between the gastric harness and internal organs.
(108) FIG. 54 is a flow chart illustrating some of the steps in a method of producing a gastric harness implant of the invention.
(109) In an alternative method, the steps of laminating the films together may be repeated after the step of machining the film.
(110) The implant can have enhanced physical properties along its peripheral edges to improve suture or staple retention strength. The strength of material along the peripheral edges may be higher to improve the physical properties in this region so that sutures do not pull out and cause failure. The material content in these regions can be increased to improve the physical properties. In addition, attachment points can be created along the edge for receiving sutures, staples, or adhesives. The attachment points can be used to attach separate panels to one another to create the gastric implant.
(111) Polytetrafluoroethylene (PTFE) polymer has useful properties as an implant material. PTFE can be processed into a microporous form using an expansion procedure. Bard Vascular Systems (Tempe, Ariz., USA) manufactures ePTFE. Expanded PTFE offers a combination of strength and flexibility together with extensive biocompatibility.
(112) Medical implant applications for the soft tissue implant technology described above may include but are not limited to gastric banding and stomach restriction procedures. The soft tissue implant may be produced in a variety of shapes and sizes for the particular indication. One may select a non-absorbable gastric implant for morbidly obese patients that require permanent treatment and long-term durability and strength. Alternatively, one may select an absorbable soft tissue implant for patients that require temporary treatment of obesity when one wants to avoid the potential complications associated with a permanent implant.
(113) In addition, the soft tissue implant product design may be produced in three-dimensional forms to facilitate sizing. An example is an implant with a curvature to construct a substantially cylindrical shape. A three dimensional structure could be machined using a system incorporating a third axis for micromachining. Alternatively, a substantially two-dimensional soft tissue implant could be thermoformed into a three-dimensional shape after machining.
EXAMPLES
Example 1
(114) A nonwoven soft tissue implant was constructed using a biaxially oriented polymer film. Expanded PTFE film measuring 0.024 inches in thickness was obtained from Bard Vascular Systems (Tempe, Ariz., USA). Expanded PTFE was machined into the design Mesh2E cell patterns using a die punch produced by Elite Tool & Die (Smithstown, Ireland).
Example 2
(115) A nonwoven soft tissue implant was constructed using biaxially oriented polymer films. Expanded PTFE film, part number 1TM22250, was obtained from BHA Technologies (Slater, Mo., USA). Twelve sheets of the film were placed between two sheets of DuPont Kapton 200HN film (Circleville, Ohio, USA). The sheet assembly was brought to 350 C. at 400 PSI of constant pressure for 15 minutes under vacuum. The laminated assembly was machined into the design Mesh2E cell patterns using a die punch produced by Elite Tool & Die (Smithstown, Ireland).
Example 3
(116) A nonabsorbable gastric wrap was created using silicone tubing. A 100 cm length of tubing was perforated in 1 cm increments with a 2 mm punching tool. The gastric wrap was implanted into a canine at Charles River Laboratories (Ballina, Co. Mayo, Ireland). The assembly was used to wrap the stomach of a 22.8 kg canine. Interrupted Mersilk 1 sutures (Ethicon, Somerville, N.J., USA) were used to secure the gastric wrap in position against the stomach. In addition, a Maxon 1 monofilament absorbable suture (United States Surgical, Norwalk, Conn., USA) was used to support the wrap by running the suture through the wrap perforations along the longitudinal axis of the stomach. The canine was fed an unrestricted high calorie diet and sacrificed at 30 days. The weight of the animal at sacrifice was 21.6 kg. The gastric wrap had incorporated into the stomach wall with a moderate degree of adhesion formation and inflammation present.
(117) A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention.
