US 3454004 A
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Description (OCR text may contain errors)
July 8?, 1969 LE|N|NGER ETAL 3,454,004
I INTRAUTERINE CONTRACEPTIVE DEVICE Filed Aug. 18, 1967 w m. 0 :a M m T A E W R N WN U S I A L L AL WM RJN United States Patent York Filed Aug. 18, 1967, Ser. No. 661,581 Int. Cl. A61f 5/46 US. Cl. 128-130 4 Claims ABSTRACT OF THE DISCLOSURE An intrauterine contraceptive device of integral,.
elastomeric composition constructed especially to resist accidental expulsion and minimize physiological discomfort.
This invention relates, in general, to intrauterine contIaceptive devices. It relates, more specifically, to an improved intrauterine contraceptive device of novel configuration and of advantageous construction.
Intrauterine contraceptive devices of the prior art are generally formed in one of several well known configurations and may be fabricated from either a rigid or an elastomeric material such as a metal or synthetic polymer. The most notable configurations of the devices formed in accordance with prior practice are those which are well known as the Lippes Loop, Margulies Spiral, Birnberg Bow and Grafenberg Ring. Each is formed substantially in accordance with empirical design considerations having only superficial reference to uterine cavity configuration. The generalized uterine cavity configuration approximates an open envelope of isosceles triangle shape with the internal os of the cervical canal located at the apex of the triangle. Although it is well known that the internal walls of the uterus forming the uterine cavity are not straightlined and may have varied degrees of curvature and are subject to extreme variations in dimensional characteristics, the prior art devices have been designed with primary consideration given to maximum permissible size for maximum coverage of the endometrial surface and retainability for effectiveness while retaining capability of insertion. Insertion of the devices formed from elastomeric materials may be accomplished by distortion or collapse of the device to an elongated configuration having a relatively small crosssectional area for passage through the cervix while cervical dilation is necessary for the rigid structure type devices. The empirical design considerations utilized in the formation of the prior art devices with only superficial reference to specific uterine cavity configuration has resulted in devices which, if retained in the uterine cavity, may have a relatively high rate of incidence of physiological complications, or, if the incidence of physiological complications is at a relatively low rate, may be particularly susceptible to spontaneous expulsion. Physiological complications which may result from utilization of an intrauterine contraceptive device include extreme discomfort to the user and irritation of the tissues with consequent inflammation and which may be accompanied by excessive or continuous bleeding. Occurrence of either spontaneous expulsion or physiological complications requiring voluntary removal prevents the possible useful application of an intrauterine contraceptive device and obtaining the resultant advantages.
An intrauterine contraceptive device represents a foreign object when inserted into the uterine cavity and it is normal for the uterus to react with muscular contractions in attempting expulsion ofthe device. As the devices are inserted into the uterine cavity through the ice cervical canal, these contractions will tend to displace the device outwardly through the cervical canal and may result in a spontaneous expulsion. A spontaneous expulsion of a device may occur unknowingly and the loss may not be noticed immediately. Loss of a device in this manner may result in an inadvertent pregnancy and, therefore, adversely afiect the advantageous, relatively low pregnancy rate which can be achieved through utilization of the devices. Accordingly, the prior art devices have been designed to substantially eliminate the possibility of spontaneous expulsion through the simple expedient of forming a device in a selected one of the prior art configurations and of a size which will normally prevent passage into the cervical canal through the internal os as a consequence of uterine contractions. The disadvantage of this simple design expedient is that, frequently, the devices are of such a relatively large size and are of such a configuration as to cause extreme discomfort to the user and may result in physiological complications necessitating voluntary removal of the device.
Materials utilized in the fabrication of intrauterine contraceptive devices in accordance with prior practice also have an important bearing on the incidence of physiological complications. Devices fabricated from metals such as silver, while not inherently harmful, do have a relatively high rate of complications and, therefore, are not generally utilized. Silkworm gut has also been utilized in the fabrication of rigid body type devices with substantial improvement over the metals but the rate of complications remains relatively high. More recently, materials of the synthetic polymer type, either in a structurally rigid or elastomer form, have been utilized with greater success. One such material, polyethylene, is now currently being used to a large extent. Polyethylene, while generally considered an innocuous material, has been known to induce physiological complications when utilized in intrauterine contraceptive devices and thus has not proven completely satisfactory for this purpose. In addition, polyethylene is chemically reactive to certain body fluids and may deteriorate when subjected to an environment where these fluids are present.
It is, therefore, the primary object of this invention to provide an improved intrauterine contraceptive device of novel configuration and construction which is adaptive to the uterine cavity for enhancement of contraceptive effectivity and having minimal susceptibility to spontaneous expulsion and minimal inducement of physiological complications.
It is another important object of this; invention to provide an improved intrauterine contraceptive device of novel configuration and which is formed from a silicone elastomer.
It is a further object of this invention to provide an improved intrauterine contraceptive device of novel configuration formed from an elastomeric material which may be readily collapsed or distorted to an elongated configuration having a relatively small cross sectional area for ease of insertion.
These and other objects and advantages of the present invention will be readily apparent from the following detailed description of two embodiments thereof and the accompanying drawings.
In the drawings:
FIGURE 1 is a sectional elevation of a uterus taken longitudinally of the uterine cavity illustrating the application thereto of an intrauterine contraceptive device according to this invention.
FIGURE is an enlarged elevational view of the intrauterine contraceptive device shown in FIGURE 1 illustrated in its relaxed, unflexed configuration, and showing in broken lines a position of resilient flexture.
FIGURE 3 is an enlarged fragmentary sectional view taken along line 33 of FIGURE 2.
FIGURE 4 is a sectional elevational view similar to FIGURE 1, but illustrating a modified form of intrauterine contraceptive device according to this invention.
FIGURE 5 is an enlarged elevational view of the intrauterine contraceptive device shown in FIGURE 4 illustrated in its relaxed, unfiexed configuration, and showing in broken lines a position of resilient fiexture.
FIGURE 6 is a fragmentary sectional view taken along line 66 of FIGURE 5.
In accordance with this invention, the improved intrauterine contraceptive devices are designed so as to conform generally to the shape of the uterine cavity for optimum effectiveness while having a high rate of retainability with a relatively low rate of incidence of physiological complications. Two froms of devices, each embodying the invention, are illustrated and described in detail. Each of these devices is of integral, one piece construction and is preferably formed from a silicone elastomer, or other synthetic elastomeric material which is non-toxic and compatible with uterine tissues. The devices are of a configuration and construction which provides satisfactory endometrial surface coverage for contraceptive effectiveness with the novel configuration designed to utilize uterine contractions in resisting expulsion. Utilization of a silicone elastomer in their fabrication not only substantially eliminates physiological complications which may result from utilization of the devices, but provides the elastomeric characteristics essential for optimum effectiveness of the novel configuration. This material also permits the devices to be readily molded in the desired configuration. Ethylene copolymers, such as: ethylene-vinyl-acetate copolymers and ethylene-acrylate copolymers, having suitable elastomeric properties may also be usable in the fabrication of the present contraceptive devices. These copolymers advantageously avoid the induced physiological complications encountered with polyethylene.
Having reference to the drawings, FIGURES 1, 2 and 3 illustrate a first form of the improved intrauterine contraceptive devices embodying the invention. The device is shown in an unflexed configuration by full lines in FIGURE 2 with typical flexing comparatively illustrated by the broken line representation. This form of device comprises anintegral, skeletal or filamentary body having a single peripheral structural member or strand formed in a coplanar, closed loop. In general, the shape approximates a trapezoid with the two nonparallel side members or strands 10 or 11 disposed in converging re lationship. Interconnecting the side strands 10 and 11 at their converging ends is a short, proximal end member or strand 12 while a relatively longer, distal end strand 13 interconnects the side strands at their opposite or divergent ends. The side and end strands are of uniform, circular cross section, as shown in FIGURE 3, with the junctures of the several strand portions being formed with a suitable radius to avoid the presence of sharp corners or edges that could result in irritation of the uterine tissues. The lengths of each of the strands are determined by consideration of the relative dimensions of the average uterine cavity with which the device is to be utilized. In any particular instance, the lengths of the end strands 12 and 13 are slightly greater than the corresponding transfundal dimensions of the average uterine cavity. Similarly, the lengths of the side strands 10 and 11 are determined by the average axial uterine dimensions for proper relativespacing of the end strands and proper positioning relative to the uterus. Preferably, the dimensions are selected to result in positioning of the longer, distal end strand 13 immediately adjacent the fundus, if not in contact therewith.
In a cord n e wi h this inven on, both of he end strands 12 and 13 are of a curvilinear configuration with the larger end strand 13 being bowed outwardly and the proximal end strand 12 being bowed inwardly of the device. This curvilinear configuration is an important aspect of this invention permitting the device to conform generally to the configuration of the uterine cavity into which it is inserted and to be retained therein. Application of opposed, laterally directed forces to the side strands 10 and 11, or the direct application of axially directed forces to the end strands 12 and 13, will result in flexing of the end strands in the manner illustrated by broken lines in FIGURE 2. Thus, the device will be seen to be capable of readily conforming to a specific uterine cavity configuration as a result of the advantageous curvilinear configuration of the end strands and the elastomeric characteristics of the material from which it is formed. A comparatively wide variance in transfundal dimensions may be readily accommodated by a given size device while exerting only a minimal force against the uterine walls through utilization of a material having appropriate elastomeric characteristics for the dimensional characteristics of the particular device, thereby reducing the possibility of discomfort or resultant physiological complications. The end strands 12 and 13 being capable of independent flexing permits the device to take advantage of any contractive forces that may be exerted by the uterus on the device in resisting expulsion.
Further accommodation of the device to the uterine cavity is provided by the flexibility of the side strands 10 and 11. Each of the side strands may be readily flexed in conformance with the curvature of the uterine walls.
As previously indicated, the material desirably utilized for formation of the intrauterine contraceptive devices of this invention is a synthetic polymer. Specifically, a silicone polymer (organopolysiloxane) has been found particularly suitable for this application. An important reason for the selection of this specific material is the lack of foreign body reaction which has been experienced with the materials utilized in accordance with prior practice. This factor substantially reduces the possibility of physiological complications which may necessitate voluntary removal or may result in spontaneous expulsion. To achieve this objective, it is essential that only a medical grade of the polymer be utilized as industrial grades may cause undesirable side effects. The silicone polymers may also be manufactured having the desired elastomeric characteristics for this application. It is necessary that the devices have adequate structural rigidity to assure retention within the uterine cavity and to also have elastomeric characteristics which will permit the advantageous flexing of the several strand portions. In the present embodiments, the strands are formed with a uniform crosssectional diameter of approximately two millimeters and the silicone polymer preferably has an elastomeric characteristic, as determined by durometer, from about Shore A60 and to about Shore D45. A material of suitable elastomeric characteristics may have a durometer within a range of about Shore A50 to about Shore D45, the exact useful range for any particular material depending on the chemical nature of the particular material and its particular physical properties, in order to provide devices of the useful material retaining the desired characteristics of this invention.
The second embodiment of the invention, see FIGURES 4, 5 and 6, is of specifically different configuration, but possesses certain structural elements in common with the first embodiment and provides the same advantages. This modified form of the intrauterine contraceptive device is shown in an unflexed configuration by full lines in FIGURE 5 with typical flexing comparatively illustrated by the broken line representation. The device also comprises an integral, skeletal or filamentary body which is formed to include a pair of spaced-apart end strands 14 and 15 connected by a single, elongated, axial strand 16. The proximal and distal end strands 14 and 15 have the same general curvilinear configuration as the corresponding end strands of the device shown in FIGURE 2, but terminate in rounded marginal end portions. The strand 1-6 performs substantially the same function as the side strands and 11 of the first embodiment in maintaining the desired spaced relationship of the end strands 14 and 15. Preferably, the interconnecting strand 16 connects with each of the end strands 14 and at substantially their mid-points. Each of the strands is also formed with a circular cross section (see FIGURE 6). When inserted in a uterine cavity, the pressure of the uterine walls bearing against the terminal ends of the end strands 14 and 15 will result in an increase in their curvature substantially as indicated by broken lines in FIGURE 5.
Each embodiment of the devices is capable of resilient collapse or distortion to an elongtaed configuration having a relatively small cross-sectional area to facilitate insertion into the uterus through the cervix without necessitating dilatation of the cervix. Insertion may be accomplished with the aid of appropriately designed instruments which are capable of retaining a device in the collapsed configuration.
After insertion in the uterine cavity, each of the devices will attempt to assume its normal unflexed configuration. However, their inserted configuration will approximate the respective configurations illustrated in FIGURES 1 and 4. Each form of the device will readily adapt to the configuration of the uterine cavity substantially as indicated by the diagrammatic illustrations. The short, proximal end strands, 12 and 14, of the respective devices are disposed adjacent the internal os 20 of the cervical canal 21 with the terminal end portions of each strand in contacting engagement with the uterine side walls and with the end strands slightly flexed thereby exerting a slight pressure on the uterus. The longer, distal end strands 13 and 15, of the respective devices are disposed adjacent the fundus 22 with the marginal end portions terminating in the cornual regions 23. Each side strand, 10 and 11, of the first embodiment is in contacting engagement with the respective side wall of the uterine cavity and conforms to the surface thereof while maintaining the spaced relationship of the end strands. The intermediate strand 16 of the second embodiment also maintains the spaced relationship of the end strands.
It is readily apparent that the improved intrauterine contraceptive devices of this invention provide the necessary endometrial surface coverage for contraceptive effectiveness for satisfactory utilization. The novel configuration and construction is adaptive to the configuration of the uterine cavity and substantially eliminates the possibility of discomfort and physiological complications. Utilization of a silicone polymer elastomer in the formation of the device in accordance with this invention further enhances the low rate of physiological complications obtainable with the devices.
According to the provisions of the patent statutes, the principles of this invention have been explained and have been illustrated and described in what is now considered to represent the best embodiment. However, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.
Having thus described this invention, what is claimed is:
1. An intrauterine contraceptive device comprising an integral, resiliently flexible, filamentary body formed from a non-irritating, synthetic elastomer and including, in its unflexed configuration, an elongated distal end strand having an outwardly bowed curvature, a proximal end strand disposed in spaced, coplanar relationship to said distal end strand, said proximal end strand having an inwardly bowed curvature and being of shorter length than said distal end strand, and at least one elongated strand between and interconnecting said distal and proximal end strands.
2. An intrauterine contraceptive device according to claim 1, wherein said elastomer consists of an organopolysiloxane having a durometer range of about Shore A to about Shore D45.
3. An intrauterine contraceptive device according to claim 1, wherein the strands of said body define a closed loop of generally trapezoidal configuration.
4. An intrauterine contraceptive device according to claim 1, wherein said distal and proximal end strands are connected substantially at their midpoints by a single elongated axial strand.
References Cited UNITED STATES PATENTS 3,253,590 5/1966 Birnberg et al 128130 3,319,625 5/1967 Appelby 128-130 3,407,806 10/1968 Hulka et al. 128-130 ADELE M. EAGER, Primary Examiner.