Expandable contraceptive transcervical fallopian tube occlusion devices having mechanical fallopian tube attachment and delivery system

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to contraceptives, and more particularly to intrafalopian contraceptive devices. Non-surgical methods for its operation are also described.

There is a worldwide demand for effective methods, contraceptive insurance and permanent sterilization. Although a variety of contraceptive and sterilization methods are available, all existing methods have limitations and disadvantages. Thus, the need for additional security, low cost, reliable methods of contraception and permanent sterilization, in developed and less developed countries, is widely known.

Many contraceptive methods available here require significant user participation and non-compliance by the user results in fairly high levels of failure. While the theoretical effectiveness of existing contraceptives, including barrier methods and hormonal therapies, has been well established, it has been found that it is difficult to overcome the user's failure to improve full effectiveness.

One form of contraceptive that is less susceptible to user default is the intrauterine device (IUD). IUDs have been found to have higher degrees of reliability, and are effective for a longer period of time, than most other commercially available contraceptives. Unfortunately, IUDs are also associated with serious infectious complications. For this reason, the use of IUDs within the United States has declined dramatically. Additionally, IUDs are subject to unplanned expulsion, and should be removed due to excessive pain or bleeding in a percentage of cases, further reducing IUD acceptance as a contraceptive method. Interestingly, the effectiveness of copper IUDs seems to be greater than that of non-metallic IUDs. The reason for this has not been fully explained.

Commercially available options for permanent sterilization include fallopian tube ligation and vasectomy. These methods are surgical, difficult to reverse, and are not available to many people in the world. It is commonly known that fertilization occurs in the fallopian tubes where the egg and sperm meet. The ligation of the tubes avoids this by the complete occlusion of the fallopian tubes.

Previously it has been proposed to reversibly occlude the fallopian tubes, for example, by in vitro formation of an elastomeric plug or otherwise by anchoring a device on any side of the narrowest region of the fallopian tubes, called the "isthmus." Such methods of occlusion of the fallopian tubes seem to promise; however, an unacceptably high percentage of the non-surgical devices proposed to date have been displaced during previous studies. Even when non-surgical intraphalopian devices have remained in place they have been found to be only moderately effective in preventing conception.

For these reasons, it would be desirable to provide highly effective intraphalopian devices, effective for contraception and sterilization. It would be particularly desirable to provide highly effective intrafalopian devices that do not require surgery for placement. It would be especially desirable if such devices and methods allowed for easy placement of the device, although they were less likely to be displaced than previously proposed non-surgical intraphalopian devices.

two. Description of the State of Related Art

The experimental use of a stainless steel intrafalopian device is described in Transcatheter Tubal Sterilization in Rabbits, Penny L. Ross, RT 29 "Investigative Radiology", p. 570-573 (1994). The experimental use of an electrolytically pure copper wire as a surgical contraceptive intrafalopian device has been described in · "Antifertility Effect of an Intrafallopian Tubal Koper Device",

DN Gupta, 14 Indian Journal of Experimental Biology, pags. 316-319 (May 1976).

English Patent Application Pub. No. 2,211,095 describes a uterine screw cap to block the fallopian tubes. European Patent Application Publication No. 0.010.812 describes a device for placing in oviducts that have extensions at either end to anchor the device. The same device is described in Dutch Patent No. 7,810,696.

The use of tubal occlusion devices is described in "Histeroscopic Oviduct Blocking with Formed-in-Place Silicone Rubber Plugs", Robert

A. Erb, Ph.D., et al., The Journal of Reproductive Medicine, pags. 65-68 (August 1979). An elastomeric tube occlusion device formed in situ is described in US Patent No. 3,805,767 issued to Erb. US Patent No. 5,065,751, issued to Wolf, describes a method and apparatus for reversibly occluding a biological tube. American Patent No. 4,612,924 issued to Cimber, describes an intrauterine contraceptive device that tightly closes the mouths of the fallopian tubes.

German Patent No. 28 03 685 issued to Brundin describes a device for plugging a body duct with a device that swells when it comes into contact with a body fluid.

Alternative contraceptive devices are described in WO96 / 40024.

In US 4,700,701 an apparatus for sterilization is described, comprising a cauterization device having a Peltier device inserted into a fallopian tube and thermally destroying a region of the fallopian tube. After cauterization, it is revealed that a medium that can be absorbed 26 is adjacent to the destroyed tissue. Subsequently, copper sulfate crystals cause intense inflammation and tissue healing.

EP 0105669 describes a contraceptive device comprising an insertable cap that is placed in the oviduct. When it is in position, the cap can expand so that it is in contact by closing the oviduct. The plug includes a metal that remembers the shape, which can be heated to change the shape and therefore the plug expands.

SUMMARY OF THE INVENTION The present invention provides a device for inhibiting conception, as set forth in claim 1.

The intrafalopian devices of the present invention are transcervically placed, mechanically anchored structures within the fallopian tube to provide long-term contraception or alternatively permanent sterilization, without the need for surgical procedures or the associated risks of increased bleeding, pain and infection. with intrauterine devices (IUD).

The intrafalopian devices of the present invention are generally composed of a structure that has a lumen crossing region with a helical outer surface. The helical surface is mechanically anchored by an elastic portion of the structure that is deflected to form an enlarged secondary shape, which preferably forms proximal and distal anchor loops. The anchor ties help prevent the helical outer surface from rotating out of position, and also directly impede axial movement within the fallopian tubes.

The use of copper in the intrafalopian device of the present invention improves its effectiveness as a contraceptive method. Devices formed of plastically deformable materials, however, are less easily restricted to the fallopian tubes. Apparently, the large variation in the actual shape and dimensions of the fallopian tubes does not provide a reliable anchor for a previously formed deformable intraphalopian device. The intrafalopian device of the present invention, therefore, is composed of an elastic structure, generally a metal spiral, which includes a copper alloy or metal coating, which is ideally composed of an alloy that includes at least 75% of copper. The spiral material typically includes a beryllium alloy, zinc, stainless steel, platinum, a shape memorizing alloy, such as Nitinol, or the like. Preferably, the spiral is composed of a beryllium and copper alloy. Although the present device will generally result in occlusion, it does not need to completely occlude the fallopian tubes to avoid the encounter of sperm and egg. In contrast, the presence of copper on the elastic structure is sufficient to provide effective contraception.

Conveniently, the present invention is used for the non-surgical placement of such intrafalopian devices by transcervical introduction. The elastic structure is restrictible in a straight configuration, for example, by the use of a core wire, largely facilitating and reducing the risks of introduction. In this way, the cost and dangers associated with existing surgical contraceptives and sterilization procedures are avoided.

In a first aspect, an intrafallopian contraceptive device according to the present invention comprises a proximal anchor, a distal anchor, and a lumen crossing region that extends between the anchors. The lumen crossing region has a helical outer surface and a cross section that is smaller than the cross sections of the distal and proximal anchors.

Preferably, the lumen crossing region is composed of an elastic structure, which generally has a tape wound on the outer surface to form the helical shape. The anchor is enhanced by a sharp outer edge on the tape. As described above, at least one of the proximal anchor, the distal anchor, and the lumen crossing region is preferably composed of copper. The proximal and distal anchors are generally composed of a deviated elastic structure to form an enlarged secondary shape, thereby allowing the device to be restricted to a straight configuration to facilitate transcervical introduction.

In another aspect, the contraceptive intrafalopian device according to the present invention is composed of a main spiral having a proximal loop, a distal loop, and an intermediate straight section between the loops. A helical tape is wound on at least a portion of the intermediate section, forming a helical surface to mechanically anchor the device inside the fallopian tube.

The tape of the present intrafalopian device generally protrudes sufficiently to firmly attach to the wall of the tubes. Preferably, the tape has a width in the range between 0.127 and 2.54 mm, a thickness in the range between 0.025 and 5.08 mm, and a passage in the range between 0.254 and 5.08 mm. The overall geometry of the device preferably facilitates the introduction and retention, although it is not rigid or large enough to interfere with internal tissue movements. Generally, the device has a length in the range between 1.5 cm and 7.5 cm when it is in a relaxed condition, while the distal loop and the proximal loop have external diameters of at least 3 mm. Preferably, the main spiral has an external diameter in the range between 0.2 mm and 5 mm.

In another aspect, a system for the operation of intrafalopian contraceptive devices is composed of a main spiral having a proximal loop, a distal loop and an intermediate straight section between the loops. Additionally, a lumen extends from a proximal end of the proximal loop to near a distal end of the distal loop. A helical tape is wound on at least a portion of the intermediate section, forming a helical surface to mechanically anchor the device inside the fallopian tube. A core wire is detachably disposed within the lumen of the main spiral. The core wire restricts the main spiral in a straight configuration, facilitating transcervical introduction. Optionally, the core wire is received threaded by the main spiral. Alternatively, a release catheter is slidably disposed on the core wire in the proximal direction of the main spiral to restrict the main spiral while the core wire is removed proximally from the fallopian tubes.

The helical tape is anchored in the fallopian tubes by the proximal and distal loops. The tape is placed on the tube wall while restricting the device in a straight configuration on the core wire to apply the twisting moment on the core wire. By removing the inner rod then the anchors are released. The distal anchor is generally inserted into the blister, distal to the isthmus, while the proximal anchor is located in the ostium. These anchors prevent the device from rotating, and also help prevent axial movement.

In yet another aspect, an intraphalopian contraceptive method comprises restricting an elastic contraceptive structure in a straight configuration over a core wire, in which the elastic structure includes a lumen crossing region that has a helical outer surface. The elastic structure is introduced transcervically into a target region of a fallopian tube, typically in the ostium region, and the inner rod is removed from the elastic structure. The elastic structure is mechanically anchored within the fallopian tubes, a portion of the elastic structure adopting an elongated secondary shape that is larger in the cross section than in the fallopian tube. Optionally, an electric current is applied through the elastic structure to the fallopian tubes, thereby performing permanent sterilization.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates a first embodiment of an intraphalopian contraceptive device according to the present invention. Fig. 2 illustrates a main spiral used in the contraceptive intrafallopian device of fig. 1. Fig. 3 illustrates a secondary spiral that has been etched onto a main spiral as used in the contraceptive intrafallopian device of fig. 1. Fig. 4 illustrates a core wire for use with the contraceptive intrafalopian device of fig. 1. Fig. 5 is a cross-sectional view of a contraceptive operating system having the contraceptive intrafalopian device of fig. 1. Fig. 6 illustrates an alternative embodiment of the present contraceptive intrafalopian device. Fig. 7 illustrates a main spiral used in the contraceptive intrafalopian device of fig. 6. Fig. 8 schematically illustrates a contraceptive operation system that includes the intraphalopian contraceptive device of fig. 6.

Figs. 9 and 10 illustrate a method of delivery of a contraceptive intrafalopian device according to the present invention. DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT

The present invention comprises an intrafallopian contraceptive device that can alternatively be used as a reversible and permanent means of contraception. Current contraceptive methods and devices minimize the danger of non-use that has restricted the effectiveness of prior art contraceptive techniques. In addition, the location of current devices within the fallopian tubes provides a reduced risk of infectious complications, increased bleeding, and pelvic pain associated with intrauterine devices (IUDs). The location and new shape of the current intrafalopian device provides important advantages over IUDs, which have been found to be susceptible to unplanned expulsion and withdrawal due to excessive pain and bleeding. The present invention takes advantage of the increased efficiency associated with copper IUDs, providing an elastic structure that includes copper that can be transcervically positioned without the need for surgery.

Although the current contraceptive method is included within a group of contraceptive techniques generally referred to as fallopian tube occlusion methods, the present invention does not necessarily have to only block the fallopian tubes to prevent fertilization. In contrast, contraception apparently provided by the disruption of ovum transport, the fertilization process, and / or ovum division. While the effect that copper has on these procedures is not fully understood, it seems that copper intraphalopian devices potentially offer significant increases in efficacy on the devices within the fallopian tubes formed of other materials. Optionally, the present invention further involves devices that promote the development of tissue within the tubes to induce occlusion of the tubes, further inhibiting conception.

Conveniently, the current elastic structures are adapted to be elastically fixed on a core wire, a core wire restricting the elastic structure in a straight configuration. Since the elastic structure has an external diameter when it is in the straight configuration that is smaller than the internal diameter of the fallopian tubes, the catheter containing the present intrafalopian device is easily inserted transcervically.

The present invention is anchored within the isthmus of the fallopian tubes, overcoming the unintended expulsion of the device and resulting in the failure of the contraceptive method. Such expulsion from the intrafalopian device has been the only most important factor that limits the effectiveness of contraceptive techniques within the easily positioned fallopian tubes. Current intrafalopian devices are generally elongated elastic structures preformed in the secondary forms. These secondary forms preferably form anchors in the proximal and distal direction of the narrowest portion of the fallopian tubes, called the isthmus. The secondary form must have an external diameter larger than the internal diameter of the isthmus.

The present device is usually easily removed by trapping the elastic structure near the proximal end and pulling in the proximal direction of the elastic structure, thereby straightening the elastic structure and allowing it to be removed without injuring the fallopian tubes. Alternatively, an electric current is applied to the device after it has been positioned within the fallopian tubes, providing permanent sterilization.

Referring now to fig. 1, a first embodiment of the present contraceptive intrafallopian device 10 is formed of an elastic main spiral 12. The main spiral 12 has a proximal end 14 and a distal end 16, the latter having an atraumatic cap 18. The main spiral 12 further includes three portions: a proximal anchor portion 20, a distal anchor portion 22, and a lumen crossing region 24. The proximal and distal anchors 20, 22 are deflected to form the anchor loops 26, as described below.

The lumen crossing region 24 comprises a substantially straight portion of the main spiral 12. A tape 28 is wound on the outer surface of the main spiral 12 to provide a helical shape. The tape 28 includes sharp outer edges 29, which firmly anchor the lumen crossing region 24 into the wall of the fallopian tubes when the torque is applied to the intrafalopian device 10. The tape is preferably formed of a very resistant biocompatible metal, ideally made of stainless steel. The tape is attached to the main spiral 12 in a proximal joint 30 and in a distal joint 32, which may be formed of solder, heat shrinkable conduit or the like.

Referring now to fig. 2, the main spiral 12 is much more easily formed in a straight configuration such as a cylindrical spiral or spring, preferably having an external diameter in the range of 0.127 to 1.27 mm, and having a length in the range of 20 mm to 150 mm Ideally, the main spiral 12 has an external diameter in the range of 0.254 to 1.27 mm and a length in the range of 30 mm to 125 mm.

Preferably, the main spiral 12 is formed of a beryllium copper alloy wire. Beryllium copper provides the necessary resistance to prevent expulsion of the device, and also provides the increased efficacy of a copper contraceptive intraphalopian device. Such beryllium copper wire will typically have a diameter of 0.0508 mm to 0.254 mm. To provide the increased efficiency of an intrafallopian copper device, the main spiral 12 preferably comprises an alloy that includes 75% copper. Alternatively, the main spiral 12 is formed of an elastic metal, such as a stainless steel, platinum, shape memorizing alloy or the like. If such materials are used, the main spiral 12 is preferably coated with copper or a copper alloy or otherwise has copper bonded thereto.

The main spiral 12 includes a transverse plane spiral 42 and a spiral thread 44. The transverse plane spiral 42 is formed with the minimum possible pitch to increase the stiffness of the main spiral 12. The spiral thread 44 typically comprises from 0.1 cm to 2 cm adjacent to the proximal end 14, and will have a pitch approximately twice the spiral in transverse plane 42.

Referring now to fig. 3, the proximal and distal anchors are formed by engraving a secondary form of flexion on the selected portions of the main spiral 12. The secondary form preferably comprises the loops 26 formed by flexing the main spiral 12, and heat treating the main spiral while flexing. A wide variety of secondary shapes can be used, including sinusoidal curves, alternating loops or loops separated by straight sections in order to form a "floron spiral", as more fully described in WO 96/40023. In all cases, the flexed secondary form should have an external cross-section 46 that is larger than the fallopian tubes to provide effective anchorage.

Referring now to fig. 4, a core wire 50 for use with the intrafalopian device 10 (Fig. 1) which comprises an elastic wire 52 bevels toward a distal end 54. The wire 52 is rigid enough to restrict the intrafalopian device 10 in a straight configuration, typically comprising stainless steel, platinum or the like. A short section of the spiral forms the threads 56 of the core wire attached to a thread joint 58. The threads 56 match the spiral and pitch of the spiral threads 44 of the main spiral 12.

Referring now to fig. 5, an intrafalopian contraceptive system 60 comprises core wire 50 inserted into a lumen 62 through the intrafalopian device 10. The intrafalopian device 10 is detachably connected by coupling the spiral threads 44 with the threads 56. In this way, the intrafalopian device 10 is decoupled by applying the twisting moment to a proximal end of core wire 50 once the device 10 is in position.

Referring now to fig. 6, an alternative embodiment of the present intrafalopian device is again formed from an elastic main spiral 112 having a proximal end 114 and a distal end 116. The first includes a friction adjustment element 115. The main spiral 112 again includes three portions: a proximal anchor portion 120, a distal anchor portion 122, and a lumen crossing region 124. The proximal and distal anchors 120, 122 are deflected here to form opposite anchor loops 26, thereby increasing the complete relaxed cross-section of the proximal and distal anchors. A tape 128 is wound on the outer surface of the main spiral 112 to provide a helical shape, as described above.

Referring now to fig. 7, the main spiral 112 comprises a spiral in uniform transverse plane 142. The secondary shape is imposed on the straight cylindrical spiral according to opposite loops 126 or alternatively according to the multiple loops of a floron spiral.

Referring now to fig. 8, an intrafalopian contraceptive system using the alternative intrafalopian device 100 includes a core wire 152 which slopes toward a distal end 154. The friction adjustment element 115 tightly engages core wire 152, which restricts the main spiral 112 in a straight configuration. A release catheter 164 is slidably disposed on the core wire 152 proximally of the alternative intrafalopian device 100, allowing the device to be released by removing the core wire 152 relative to the release catheter.

The use of the present contraceptive intrafallopian device will be described with reference to figs. 9 and 10. A cannula 70 of the uterine introducer is inserted transcervically through a uterus 72 to the region of an ostium 74. Alternatively, a hysteroscope can be used instead of cannula 70.

The intraphalopian contraceptive system 60 is advanced distally from the introducing cannula 70 and maneuvered through the fallopian tubes, preferably until the intraphalopian device 10 extends distally to the isthmus. Optionally, the intraphalopian contraceptive system 60 is autonomously guided, with the core wire 52 flexed near the distal end 54 to aid maneuvering within the lumen. Alternatively, a guide wire and catheter are first advanced into the fallopian tubes, and the guide wire is replaced with the intraphalopian contraceptive system 60. In any case, the intrafalopian device is axially positioned with the lumen crossing region 24 within a target region 84 contiguous to the isthmus 80. Preferably, at least one loop of the distal anchor 22 is distal of the target region 84, and at least one loop of the proximal anchor 20 is proximal of the target region 84 to form distal and proximal curvatures of the anchor.

Once the intrafallopian device 10 is properly positioned, the twisting moment is applied to the core wire 50 to fix the tape 28 on the wall of the tubes. The core wire can then be unscrewed from the intrafalopian device 10 by rotating the core wire in the opposite direction, decoupling the threads 56 of the spiral threads 44. The core wire is then free to slide proximally, releasing the main spiral. As the distal end of the main spiral is released, a curvature 90 of the distal anchor is formed. Also, a proximal loop forms a curvature 92 of proximal anchor. The anchorage curvatures help to axially restrict the device within the fallopian tubes and also prevent rotation around the helical shape of the lumen crossing region 24. As seen in fig. 10, ties do not need to assume their relaxed form to provide effective proximal or distal anchors.

Permanent sterilization is possible by passing a current through the core wire to the intrafalopian device before removing the core wire. The tissue of the fallopian tubes that is in contact with the intrafalopian device is removed, and thus attached to the present intrafalopian device. This action also causes permanent damage to the tube, leading to the formation of the scar tissue that encapsulates the intrafalopian device and causes permanent occlusion of the lumen of the tubes. Clearly, the core core / spiral wire interface must be conductive to allow the present non-surgical method of permanent sterilization.

In conclusion, the present invention provides an intraphalopian contraceptive device that can be positioned without surgery. Although the foregoing is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents can be used. For example, it

5 You can record a wide variety of secondary shapes, including open loops, continuous curvatures, sinusoidal curves or the like, over the main spiral. Therefore, the above description should not be considered as limiting the scope of the invention, which instead is defined only by the appended claims.

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