Surgery – Female reproductory tract shields – supports – or birth...
Reexamination Certificate
1998-06-08
2004-03-16
Brown, Michael A. (Department: 3733)
Surgery
Female reproductory tract shields, supports, or birth...
C128S831000
Reexamination Certificate
active
06705323
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to contraception, and more particularly to intrafallopian contraceptive devices and nonsurgical methods for their delivery.
Worldwide demand exists for safe, effective methods of both contraception and permanent sterilization. Although a variety of contraception and sterilization methods are available, all of the existing methods have limitations and disadvantages. Thus, the need for additional safe, low cost, reliable methods of contraception and permanent sterilization, both in developed and less developed countries, is widely recognized.
Many presently available contraception methods require significant user involvement, and user non-compliance results in quite high rates of failure. While the theoretical effectiveness of existing contraceptives, including barrier methods and hormonal therapies, is well established, overcoming user noncompliance to improve overall efficacy has proven difficult.
One form of contraception which is less susceptible to user noncompliance is the intrauterine device (IUD). IUDs have been found to have higher rates 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 decreased dramatically. Additionally, IUDs are subject to unplanned expulsion, and must be removed due to excessive pain or bleeding in a percentage of cases, further reducing the acceptance of the IUD as a contraceptive method. Interestingly, the efficacy of copper IUDs appears to be higher 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, are difficult to reverse, and are not available to many people in the world. It is common knowledge that fertilization occurs in the fallopian tubes where the sperm and ovum meet. Tubal ligation avoids this by complete occlusion of the fallopian tubes.
It has previously been proposed to reversibly occlude the fallopian tubes, for example, by in vitro formation of an elastomeric plug, or otherwise anchoring a device on either side of the narrowest region of fallopian tube, called the “isthmus.” Such fallopian tube occlusion methods appear promising; however, an unacceptably high percentage of the non-surgical devices proposed to date have become dislodged during previous studies. Even where non-surgical intrafallopian devices have remained in place, they have been found to be only moderately effective at preventing conception.
For these reasons, it would be desirable to provide effective, reliable intrafallopian devices for contraception and sterilization. It would be particularly desirable to provide highly effective intrafallopian devices which did not require surgery for placement. It would be especially desirable if such devices and methods allowed easy placement of the device, but were less susceptible to being dislodged than previously proposed non-surgical intrafallopian devices.
2. Description of the Related Art
The experimental use of a stainless steel intrafallopian device is described in
Transcatheter Tubal Sterilization in Rabbits,
Penny L. Ross, RT 29 “Investigative Radiology”, pp. 570-573 (1994). The experimental use of an electrolytically pure copper wire as a surgical contraceptive intrafallopian device in rats was described in “Antifertility Effect of an Intrafallopian Tubal Copper Device”, D. N. Gupta, 14
Indian Journal of Experimental Biology,
pp. 316-319 (May 1976).
U.K. Patent Application Pub. No. 2,211,095 describes a uterine screw plug for blocking the fallopian tube. European Patent Application Pub. No. 0,010,812 describes a device for placement in the oviducts having enlargements at either end for anchoring the device. The same device appears to be described in Netherlands Patent No. 7,810,696.
The use of tubal occlusion devices is described in “Hysteroscopic Oviduct Blocking With Formed-in-Place Silicone Rubber Plugs”, Robert A. Erb, Ph.D., et al.,
The Journal of Reproductive Medicine,
pp. 65-68 (August 1979). A formed-in-place elastomeric tubal occlusion device is described in U.S. Pat. No. 3,805,767, issued to Erb. U.S. Pat. No. 5,065,751, issued to Wolf, describes a method and apparatus for reversibly occluding a biological tube. U.S. Pat. No. 4,612,924, issued to Cimber, describes an intrauterine contraceptive device which seals 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 which swells when in contact with a body fluid.
Alternative contraceptive devices are disclosed in co-pending U.S. patent application Ser. No. 08/474,779, the full disclosure of which is herein incorporated by reference.
SUMMARY OF THE INVENTION
The present invention provides intrafallopian devices and methods for their placement to prevent conception. The intrafallopian devices of the present invention are transcervically delivered and mechanically anchored within the fallopian tube to provide long term contraception, or alternatively permanent sterilization, without the need for surgical procedures or the risks of increased bleeding, pain, and infection associated with intrauterine devices (IUDs).
The intrafallopian devices of the present invention will often comprise a structure having a lumen-traversing region with a helical outer surface. The helical surface is mechanically anchored by a resilient portion of the structure which is biased to form an enlarged secondary shape, preferably forming distal and proximal anchoring loops. The anchoring loops help prevent the helical outer surface from rotating out of position, and also directly deter axial motion within the fallopian tube. In alternative embodiments, anchoring may be provided by a straight coil which is resiliently deflected by the axial curvature of the tortuous fallopian tube, and a radially expandable braid, malecott, or some other tubular structure may help affix the device within the fallopian tube.
The use of copper in the intrafallopian device of the present invention improves its efficacy as a contraceptive method. Devices formed from plastically deformable materials, however, are less readily restrained in the fallopian tube. Apparently, the large variation in the actual shape and dimensions of fallopian tubes does not provide reliable anchoring for a pre-formed deformable intrafallopian device. The intrafallopian device of the present invention therefore often comprises a resilient structure, usually a metallic coil, which includes a copper alloy or plating, ideally comprising an alloy including at least 75% copper. The coil material typically includes beryllium, zinc, stainless steel, platinum, a shape memory alloy, such as Nitinol®, or the like. Preferably, the coil is composed of an alloy of beryllium and copper.
Although the present device will generally result in occlusion, it need not completely occlude the fallopian tube to prevent the meeting of the sperm and ovum. Instead, in some embodiments, the presence of the copper on the resilient structure is sufficient to provide effective contraception. Hence, contraception can be provided by disrupting the normal architecture and/or function of the fallopian tube, despite the presence of an open lumen. This concept is referred to herein as “functional occlusion”. As used herein, a device which provides functional occlusion means that the device, when implanted in the fallopian tube, disrupts the normal architecture and/or functioning of the fallopian tube so as to inhibit fertilization and/or conception.
Conveniently, the present invention further comprises non-surgical placement of such intrafallopian devices by transcervical introduction. The resilient structure is restrainable in a straight configuration, e.g., by use of a corewire, greatly facilitating and reducing
Bacich Steven
Gurskis Donnell W.
Khera Ashish
Nikolchev Julian N.
Ton Dai T.
Barrish, Esq. Mark D.
Brown Michael A.
Conceptus, Inc.
Townsend and Townsend / and Crew LLP
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