U.S. patent number 3,789,838 [Application Number 05/116,867] was granted by the patent office on 1974-02-05 for force transmitting intrauterine device.
Invention is credited to Erick-Pierre Fournier, Alberto Lomeo.
United States Patent |
3,789,838 |
Fournier , et al. |
February 5, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
FORCE TRANSMITTING INTRAUTERINE DEVICE
Abstract
An intrauterine contraceptive device having substantial surface
area for contact with the endometrium and capable of being
releasably contracted to a size and shape for ready passage into
the uterus and, when released, of expanding to conformably engage
the walls of the uterine cavity in the mid-uterine area above the
level of the internal so to resist expulsion, and thereafter of
being readily removed, together with an introducer implement for
releasably contracting the device in the proper orientation for
insertion are disclosed.
Inventors: |
Fournier; Erick-Pierre (New
York, NY), Lomeo; Alberto (New York, NY) |
Family
ID: |
22369719 |
Appl.
No.: |
05/116,867 |
Filed: |
February 19, 1971 |
Current U.S.
Class: |
128/839;
128/840 |
Current CPC
Class: |
A61F
6/142 (20130101) |
Current International
Class: |
A61F
6/00 (20060101); A61F 6/14 (20060101); A61f
005/46 () |
Field of
Search: |
;128/127-131,261,263,260
;24/81,252 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
A H. Robins Co. Advertising Booklet, "Dalkon Shield," A. H. Robins
Co., Richmond, Va., Nov. 1970..
|
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: McGowan; J. C.
Attorney, Agent or Firm: Morgan, Finnegan, Durham &
Pine
Claims
1. An intrauterine contraceptive device comprising a substantially
membranous readily deformable and inwardly contractible but
resilient planar body having an outer substantially lobate contour
including upper and lower pairs of resilient, structural uterine
wall bearing lobes laterally disposed in substantial mirror-image
relation with respect to a common symmetrical axis extending
longitudinally therebetween when in unstressed condition, said
planar body further comprising a pair of diagonally extending
crossed structural force transmitting members operatively
interconnecting in direct force transmitting relation diagonally
opposed lobes of said upper and lower lobe pairs whereby forces
exerted on said lobes by said uterine walls are contralaterally
transmitted and diffused through said body and inward compression
of a lobate region by uterine wall forces being thereon causes the
diagonally associated lobate region to exert increased outward
pressure on said
2. An intrauterine contraceptive device capable of being readily
compressed for passage into the uterine cavity and, when released,
of expanding to conformably engage the uterine walls to resist
expulsion, said device comprising a substantially planar, readily
deformable, pliable but resilient body of a resilient substantially
filamentary frame having an outer substantially lobate contour
including upper and lower pairs of resilient, structural uterine
wall bearing lobes laterally, outwardly disposed in mirror-image
relation defining a common longitudinal axis of symmetry when in
unstressed condition, said device being adapted by location within
said uterine cavity such that said axis is substantially aligned
with the cervical canal, said filamentary frame of said body also
having a pair of resilient, structural force transmitting members
diagonally extending in crossed relation across said axis
operatively interconnecting in force transmitting relation
diagonally opposed lobes of said upper and lower pairs, said force
transmitting members being independently freely rotationally and
translationally movable relative to each other, said upper and
lower structural lobes and said pair of structural force
transmitting members defining a configuration having two free ends
and being continuously traceable between said two ends, whereby
forces exerted on said lobes by said uterine walls are
contralaterally transmitted and diffused through said body and
inward compression of any one of said four lobate regions by
uterine wall forces bearing thereon causes the diagonally
associated lobate region to exert increased outward pressure on
said uterine wall, said resilient body further comprising membrane
means operatively associated with said frame providing substantial
surface area for contact with the endometrium when said device
3. A device as defined in claim 2, said membrane means forming
membranous surfaces having asperities substantially regularly
distributed thereon.
4. An interauterine contraceptive device capable of being readily
compressed for passage into the uterine cavity and, when released,
of expanding to conformably engage the uterine walls to resist
expulsion, said device comprising a substantially planar readily
deformable pliable but resilient body having an outer substantially
lobate contour including upper and lower pairs of resilient,
structural uterine wall bearing lobes laterally, outwardly disposed
in mirror-image relation defining a common longitudinal axis of
symmetry when in unstressed condition, said device being adapted
for location within said uterine cavity such that said axis is
substantially aligned with the cervical canal, said resilient body
further comprising a pair of resilient, structural force
transmitting members diagonally extending in crossed relation
across said axis operatively interconnecting in force transmitting
relation diagonally opposed lobes of said upper and lower pairs,
said force transmitting members being independently freely
rotationally and translationally movable relative to each other,
said upper and lower structural lobes and said pairs of structural
force transmitting members defining a configuration having two free
ends and being continuously traceable between said two ends,
whereby forces exerted on said lobes by said uterine walls are
contralaterally transmitted and diffused through said body and
inward compression of any one of said four lobate regions by
uterine wall forces bearing thereon causes the diagonally
associated lobate region to exert increased outward pressure on
said uterine wall, and knurl forming means disposed on the outer
wall bearing surfaces of said lobes for gripping the uterine wall
to provide stability and
5. An intrauterine contraceptive device capable of being readily
compressed for passage into the uterine cavity and, when released,
of expanding to conformably engage the uterine walls to resist
expulsion, and thereafter of being readily contracted for removal,
said device comprising two substantially similar resilient S-shaped
force transmitting members having respective upper and lower
arcuate sections, said members in unstressed conditions being
arranged in substantially planar overlapped mirror-image relation
with their said upper and lower arcuate sections outwardly disposed
with respect to a symmetrical axis extending longitudinally
therebetween, said device being adapted for location within said
uterine cavity with said axis substantially aligned with the
cervical canal and said upper and lower arcuate sections forming
lateral uterine wall bearing lobes, said device further comprising
spring-hinge means normally resiliently joining the terminal
portions of said lower arcuate sections and manually operable
withdrawal means operatively associated therewith for deactuating
the resilient forces of said hinge means to permit said force
transmitting members to be non-resiliently readily contracted
towards said longitudinal axis for removal of the device, said
upper arcuate sections of said members terminating in free ends,
and said spring-hinge means comprising a substantially filamentary
extension of said force transmitting members forming an inverted-V
expansion joint
6. A device as defined in claim 5, said withdrawal means comprising
zones of weakness formed in said force transmitting members at
their junctions with the base of said inverted-V joint and means
for inverting said joint, said means comprising filament means
connected to said apex of said joint and adapted to be readily
externally accessible for exerting a downward
7. An intrauterine contraceptive device capable of being readily
compressed for passage into the uterine cavity and, when released,
of expanding to conformably engage the uterine walls to resist
expulsion, and thereafter of being readily contracted for removal,
said device comprising two substantially similar resilient S-shaped
force transmitting members having respective upper and lower
arcuate sections, said members in unstressed condition being
arranged in substantially planar overlapped mirror-image relation
with their said upper and lower arcuate sections outwardly disposed
with respect to a symmetrical axis extending longitudinally
therebetween, said device being adapted for location within said
uterine cavity with said axis substantially aligned with the
cervical canal and said upper and lower arcuate sections forming
lateral uterine wall bearing lobes, said device further comprising
spring-hinge means normally resiliently joining the terminal
portions of said lower arcuate sections and manually operable
withdrawal means operatively associated therewith for deactuating
the resilient forces of said hinge means to permit said force
transmitting members to be non-resiliently readily contracted
towards said longitudinal axis for removal of the device, aid upper
arcuate sections of said members terminating in free ends, and
membrane means secured to said force transmitting members providing
substantial surface area for frictional contact with the
endometrium when said device
8. A device as defined in claim 7, said membrane means forming
membranous surfaces having asperities substantially regularly
distributed thereon.
9. A device as defined in claim 7, said membrane means comprising a
membranous region secured to the lower terminal portion of each of
said
10. A device as defined in claim 7, said membrane means comprising
a membranous region operatively associated with said force
transmitting
11. A device as defined in claim 7, said membrane means comprising
a membranous region secured to each of said lower arcuate sections
of said
12. An intrauterine contraceptive device capable of being readily
compressed for passage into the uterine cavity and, when released,
of expanding to conformably engage the uterine walls to resist
expulsion, and thereafter of being readily contracted for removal,
said device comprising two substantially similar resilient S-shaped
force transmitting members having respective upper and lower
arcuate sections, said members in unstressed condition being
arranged in substantially planar overlapped mirror-image relation
with their said upper and lower arcuate sections outwardly disposed
with respect to a symmetrical axis extending longitudinally
therebetween, said device being adapted for location within said
uterine cavity with said axis substantially aligned with the
cervical canal and said upper and lower arcuate sections forming
lateral uterine wall bearing lobes, said device further comprising
spring-hinge means normally resiliently joining the terminal
portions of said lower arcuate sections and manually operable
withdrawal means operatively associated therewith for deactuating
the resilient forces of said hinge means to permit said force
transmitting members to be non-resiliently readily contracted
towards said longitudinal axis for removal of the device, said
upper arcuate sections of said members terminating in free ends,
and knurl forming means disposed on the outer wall lobe bearing
surfaces of said arcuate sections of said force transmitting
members for gripping the uterine wall to provide stability and
resistance to downward displacement
13. An intrauterine contraceptive device capable of being readily
compressed for passage into the uterine cavity and, when released,
of expanding to conformably engage the uterine walls to resist
expulsion, and thereafter of being readily contracted for removal,
said device comprising two substantially similar resilient S-shaped
force transmitting members having respective upper and lower
arcuate sections, said members in unstressed condition being
arranged in substantially planar overlapped mirror-image relation
with their upper and lower arcuate sections outwardly disposed with
respect to a symmetrical axis extending longitudinally therebetween
and wherein the overall unstressed transverse extent of said device
between said pair of upper arcuate sections is substantially
greater than between said pair of lower arcuate sections, and said
force transmitting members overlap one another substantially
mid-way along said longitudinal axis and extend thereat in relation
to one another at an angle within the range of about 0.degree. to
30.degree., said device being adapted for location within said
uterine cavity with said axis substantially aligned with the
cervical canal and said upper and lower arcuate sections forming
lateral uterine wall bearing lobes, said device further comprising
spring-hinge means normally resiliently joining the terminal
portions of said lower arcuate sections and manually operable
withdrawal means operatively associated therewith for deactuating
the resilient forces of said hinge means to permit said force
transmitting members to be non-resiliently readily contracted
towards said longitudinal axis for removal of the device, said
upper arcuate sections of said members terminating in free ends,
said device having an overall dimension such that when in position
within the uterus, its lower extremity is at a level substantially
above the average level of the internal os and its lateral
extremities are substantially spaced apart from the extreme
14. In an intrauterine contraceptive device having a longitudinal
axis substantially aligned with the cervical canal when said device
is properly positioned in the uterus and having two substantially
filamentary arms normally substantially symmetrically disposed with
respect to said axis in movable spaced apart relation and extending
upwardly away from the cervical canal, spring-hinge means joining
the terminal portions of said arms nearest said cervical canal when
said device is properly positioned in the uterus resiliently
resisting inward contraction of said arms towards said axis, and
withdrawal means operatively associated with said spring-hinge
means for deactuating the resilient forces of said hinge means to
permit said arms to be non-resiliently readily inwardly contracted
towards said longitudinal axis for removal of the device, said
spring-hinge means comprising a substantially filamentary extension
of said arms forming an inverted-V expansion joint having an apex
substantially coincident with said longitudinal axis and displaced
with respect to the lowermost extremities of said arms upwardly
away from said cervical canal when said device is properly
positioned in the uterus, said withdrawal means comprising zones of
weakness formed in said arms at their junctions with the base of
said inverted-V joint and filament means affixed to said apex for
inverting said joint upon exertion of a downward force thereon,
said filament means being adapted to be readily externally
15. In a device as defined in claim 14, said inverted-V joint
having a substantially rounded contour at its apex serving as a
means for dilating
16. In an intrauterine contraceptive device having a longitudinal
axis substantially aligned with the cervical canal when said device
is properly positioned in the uterus and having two substantially
filamentary arms normally substantially symmetrically disposed with
respect to said axis in movable spaced apart relation and extending
upwardly away from the cervical canal, spring-hinge means joining
the terminal portions of said arms nearest said cervical canal when
said device is properly positioned in the uterus resiliently
resisting inward contraction of said arms towards said axis, said
spring-hinge means comprising a filamentary extension of said arms
forming a reversible inverted-V expansion joint having an apex
substantially coincident with said longitudinal axis and displaced
with respect to the lowermost extremities of said arms upwardly
away from said cervical canal when said device is properly
positioned in the uterus, means accessible externally of the uterus
for inverting said inverted-V joint so that its said apex is
substantially coincident with said longitudinal axis and displaced
with respect to the lowermost extremities of said arms downwardly
towards said cervical canal, said joint having a substantially
rounder contour at its said apex when inverted whereby said joint
serves to dilate the cervical canal during removal of said device.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
Overpopulation presents such potentially disastrous socio-economic
and ecological consequences that safe, effective, convenient and
readily accessible means of curbing the world's birth rate other
than through sterilization and abortion must be developed and
massively implemented in the not-too-distant future.
Currently available modes of contraception fall broadly into three
categories. Physical and/or chemical barriers interposed between
the sperm and the ovum such as condoms, diaphragms, spermicidal
foams, creams and jellies. Hormonal interference with ovulation
and/or implantation of the fecundated ovum which can be either of
the oral, injectable or implantable type. Intrauterine
contraceptive devices which, according to current theory, are
believed to activate and to attract the presence of phagocytic
cells through irritation of the endometrial cavity, thereby
isolating the blastocyst and preventing its implantation, although
the exact contraceptive mechanism involved has yet to be fully
understood.
All these methods have not been without varying forms and degrees
of drawbacks. Let alone the fact that low incidence of pregnancy
with condoms, diaphragms and sperm-killing chemicals is heavily
related to the skill and care of the user, they are generally
regarded as clumsy and inconvenient. Besides their relatively high
cost, they require, in order to be beneficial, a definite amount of
sophistication and sustained individual motivation which inhibit
their wide-spread usage, particularly among lower socio-economic
groups.
Although rated the most effective to date, any hormonal treatment
demands continuous periodic supervision by highly qualified medical
personnel for the assessment and evaluation of its systemic
effects, which constitutes a definite limiting factor. In addition,
they still imply on the part of the user a measurable degree of
self-discipline, particularly among highly mobile population groups
resorting to "one-a-day" oral contraceptives.
In contrast to the other modes of contraception, the intrauterine
device at least theoretically represents potentially the ideal
method of mass population control for both developed and developing
countries. This contraceptive approach is basically inexpensive and
convenient, and requires a minimum of attention and supervision all
of which militate in favor of its use-effectiveness. Furthermore,
clinical experience with such devices has indicated the potential
effectiveness and reliability of this approach to contraception
without the need to alter natural hormonal balances.
Any intrauterine contraceptive device, before it can expect to meet
with a full measure of success, should ideally satisfy the
following objectives:
The pregnancy rate should match or closely approach the low
incidence level of hormonal contraceptives.
The rate of spontaneous expulsion should be very low.
Side effects such as pain, cramps, bleeding and other discomfort
must be minimal so as to encourage the user to continue.
The design of the intrauterine device and of its introducer
implement as well as the insertion procedure, should be such that
uterine perforation is made virtually impossible during insertion
of the device.
The structural design of the device should be such as to
comfortably fit the uterine cavity of all women, especially
nulligravidas.
The introduction of the device, as well as its removal, should be
painless, easy and relatively fast to perform by either physicians
or paramedical personnel after a short period of training.
The material composition of the device must be such that it causes
no harm to the human body.
The device should be able to be mass produced at a low
manufacturing cost.
Heretofore, this mode of contraception has not attained the level
of reliability and acceptance indicated by theoretical
considerations, the available devices having been found lacking in
one or more of the foregoing areas. The principal shortcoming has
been in an inability to control the rate of spontaneous expulsion
with accompanying side effects such as pain and bleeding.
On the basis of the body of current clinical knowledge, the
relationships between some of the physical characteristics of a
device and its wanted and unwanted effects can be summarized in the
following table where a plus sign indicates an increase as a direct
function of a physical factor, a minus sign a decrease and a zero
no significant change.
Physiological Effects Physical Characteristics Pain Bleed- Expul-
Preg- ing sion nancy Resilience + + - 0 Stiffness + + - 0 Size + +
- 0 Surface Contact 0 + - - Roughness + + 0 - Irritation 0 0 0
-
As can be observed, for instance, the rate of pregnancy and
expulsion is inversely proportional to the extent of surface
contact of the device with the endometrial tissues, but with the
disadvantage of increased bleeding; whereas a high degree of
resilience and stiffness tends to lower the expulsion rate while
causing at the same time the unwanted effects of greater pain and
bleeding. Similarly, too large a size in the dimensions of a device
will lower the expulsion rate without too much effect on the
pregnancy rate while increasing bleeding and pain due to the
distention caused to the uterine cavity.
Having in mind the foregoing, the present invention has as its
general object the provision of an intrauterine contraceptive
device which eliminates the shortcomings and drawbacks of the prior
art. More particularly, the invention has as its object the
provision of a device and means for inserting same which embodies
all of the objectives set forth above, especially one which couples
low incidence of pregnancy with high resistance to spontaneous
expulsion and ease of insertion and removal.
Briefly and generally, the invention in its broad aspects comprises
a device having a substantially planar deformable but resilient
body capable of being releasably contracted for ready passage in to
the uterus and, when released, of expanding to conformably engage
the uterine walls in the mid-uterine area substantially above the
average level of the internal os to resist expulsion. In accordance
with a basic principle of the invention, the device has a
substantially lobate outer contour including upper and lower pairs
of structural uterine wall bearing lobes disposed in substantially
symmetrical relation about a longitudinal axis extending
therebetween with diagonally opposed upper and lower lobes of said
lobe pairs directly coupled in contralateral force transmitting
relation by structural force transmitting means extending in
crossed relation diagonally across said axis, the device being
adapted for proper orientation in the uterus with its longitudinal
axis substantially coaxial with the cervical canal.
In one preferred form of the invention, the device has
substantially the configuration of a figure 8, open at the top, the
operative elements including two substantially similar resilient
S-shaped force transmitting members having upper and lower arcuate
lobe forming sections and arranged in overlapped mirror-image
relation with their said arcuate sections outwardly disposed with
respect to a symmetrical axis longitudinally extending therebetween
as aforesaid. In accordance with a further principle of the
invention, the terminal portions of the lower arcuate sections
located nearest the cervical canal when the device is properly
oriented in the uterus are resiliently joined via spring-hinge
means resiliently resisting inward compression of the members
towards the longitudinal axis, and externally accessible withdrawal
means is provided for deactuating the spring-hinge means to permit
the members to be readily contracted for removal.
In a preferred embodiment, the spring-hinge means comprises a
filamentary extension of the force transmitting members having the
form of an "inverted-V" expansion joint with an apex substantially
coincident with the longitudinal axis, the withdrawal means
comprising zones of weakness formed at the junctions of the members
with the V joint and filament means affixed to the apex of the
joint and readily externally accessible whereby the manual
application of a force for removal of the device will result in the
joint being inverted and a deactuation of its spring energy
normally resisting contraction of the force transmitting members
towards the longitudinal axis.
In accordance with a further and preferred feature of the
invention, the device is formed with a series of plastic
membraneous regions which, still more preferably, incorporate
minute regularly distributed surface protuberances or asperities
giving the device substantial surface area for contact and surface
irritation of the endometrium.
In accordance with still another aspect of the invention, the
arcuate sections of the force transmitting members are provided on
their outer wall bearing lobe surfaces with knurl forming
protuberances for gripping the uterine wall to provide stability
and resistance to downward displacement of the device.
Means in accordance with the invention for introducing the
contraceptive device into the uterus comprises a shaft having
handle means formed in one end and means formed in the other end
having a bulbous searching head for releasably holding the device
in a properly oriented contracted condition, the shaft being formed
with a curvilinear profile intermediate its ends having a double
reverse curvature whereby the handle section and holding section
oppositely extend in axially offset substantially parallel
relation. This means for holding the device comprises a linear
section of the shaft defining a cavity having a back wall and
locating pin means operatively associated with the cavity for
cooperating with pin engaging means formed in the device whereby
the device is releasably retained within the cavity with its
longitudinal axis parallel to the axis of the shaft and its force
transmitting members contracted towards the longitudinal axis with
their normally free ends held in fixed spatial relation.
Preferred dimensional and geometrical parameters in accordance with
the invention are that the outer wall bearing surfaces of the upper
arcuate sections be normally spaced apart a substantially greater
distance than the corresponding surfaces of the lower arcuate
sections, that the force transmitting members cross over one
another at substantially the mid-point of the device taken along
the longitudinal axis and that they extend in relation to one
another at an angle of about 0.degree.-30.degree., and that the
lowermost extremity of the device when positioned in the uterus
lies substantially above the average level of the internal os, the
device being adapted to lie in the mid-uterine area.
Having summarized the invention, a detailed description follows
with reference for illustrative purposes to the accompanying
drawings which form part of the specification, of which:
FIG. 1 is a diagrammatical view of the uterus illustrating its
muscular structure;
FIG. 2 is a diagrammatical view illustrating the muscular dynamics
of the uterus including the two major centers of concentric
forces;
FIG. 3 is a diagrammatical view of an intrauterine contraceptive
device embodying the invention in its elemental concept
illustrating same unstressed within the uterine cavity;
FIGS. 4, 5 and 6 are diagrammatical views similar to FIG. 3
illustrating the device conforming to the physiology of the uterine
cavity under various contractive forces and the force transmitting
and diffusing mechanism of the device to prevent expulsion;
FIG. 7 is a diagrammatical view similar to FIG. 3 illustrating the
device conforming to the uterine cavity in the event that it
accidentally assumes an upside-down position;
FIG. 8 is an elevational view, partially diagrammatical, of a
preferred embodiment of the invention;
FIG. 9 is a cross-sectional view of the device of FIG. 8 taken
along line 9--9 thereof;
FIG. 10 is a cross-sectional view of the device of FIG. 8 taken
along line 10--10 thereof;
FIG. 10A is a cross-sectional view of the device illustrating an
alternate cross-sectional configuration to that of FIG. 10;
FIG. 11 is a cross-sectional view of the device of FIG. 8 taken
along line 11--11 thereof;
FIG. 12 is a cross-sectional view of the device of FIG. 8 taken
along line 12--12 thereof;
FIG. 12A is a cross-sectional view illustrating an alternate
cross-sectional configuration to that of FIG. 12;
FIG. 13 is a fragmentary cross-sectional view of the device taken
in perspective at the cross-over region of the force transmitting
members of the device;
FIG. 14 is a diagrammatical elevational view illustrating in
accordance with the invention an alternate membranous configuration
to that of FIG. 8;
FIGS. 15-18 are fragmentary diagrammatical views illustrating, in
accordance with the invention, four alternate lobate knurl
configurations for the arcuate sections of the device;
FIG. 19 is a chart illustrating various possible membrane asperity
configurations in accordance with the invention;
FIGS. 20-23 are diagrammatical elevational views illustrating a
contraceptive device in accordance with the invention being removed
from the uterine cavity;
FIG. 24 is an elevational view of an introducer implement in
accordance with the invention releasably holding a contraceptive
device similar to that of FIG. 8;
FIG. 25 is a top plan view of the introducer and device combination
of FIG. 24;
FIG. 26 is a diagrammatical elevational view illustrating the
technique for inserting a contraceptive device utilizing the
introducer implement of FIG. 24;
FIG. 27 is a sectional view taken transversely of the uterine
cavity illustrating the contraceptive device held in its contracted
state by the introducer as in FIG. 26 and further illustrating the
manner by which the device is disengaged;
FIG. 28 is a view similar to FIG. 27 illustrating the contraceptive
device fully expanded after disengagement from the introducer
conformably engaging the walls of the uterine cavity;
FIGS. 29, 30 and 31 are enlarged side and end elevational and
bottom plan views, respectively, of the contraceptive device and
introducer combination of FIG. 24;
FIGS. 32, 33 and 34 are views similar to FIGS. 29, 30 and 31,
respectively, illustrating an introducer implement of alternate
construction in accordance with the invention releasably holding a
contraceptive device similar to that of FIG. 8;
FIGS. 35-37 are diagrammatical views of three alternate introducer
locating pin configurations in accordance with the invention for
releasably engaging a contraceptive device as herein
illustrated.
FIGS. 38, 39 and 40 are views similar to FIGS. 29, 30 and 31,
respectively, illustrating still another alternate introducer
construction in accordance with the invention releasably holding a
contraceptive device similar to that of FIG. 8;
FIGS. 41, 42 and 43 are views similar to FIGS. 29, 30 and 31,
respectively, illustrating in combination with a contraceptive
device as herein illustrated yet another introducer construction in
accordance with the invention;
FIG. 44 is an enlarged top plan view of the contraceptive device
and introducer combination of FIG. 41;
FIG. 45 is a fragmentary diagrammatical view of a contraceptive
device in accordance with the invention having alternate pin
engaging locations to that of FIG. 8 for use with the introducers
of FIGS. 32, 38 and 41; and
FIG. 46 is a perspective view of an intrauterine contraceptive
device and introducer combination in accordance with the invention
prepackaged for use.
Turning now to the drawings in detail wherein like reference
characters are employed to designate like parts throughout, an
intrauterine device embodying the invention in its elemental
concept is illustrated diagrammatically in FIG. 3, the device being
shown in unstressed condition within the uterine cavity.
In accordance with the invention, the device comprises a
substantially filamentary compressible resilient body having a
longitudinal axis S--S which extends substantially coaxially with
the cervical canal when the device is properly positioned within
the uterine cavity as shown in FIG. 3. The operative elements of
the illustrative embodiment include two substantially similar
S-shaped resilient force transmitting members 50 and 51 having
upper arcuate arm sections 52 and 53, respectively, and lower
arcuate arm sections 54 and 55, respectively, members 50 and 51
being disposed in overlapped mirror-image relation with respect to
the longitudinal axis S--S to form a substantially planar body. The
lower arcuate arm sections 54 and 55 at their terminal portions are
joined via spring-hinge means 57 whereas the terminal portions of
the upper arcuate arm sections 52 and 53 are normally disposed in
overhanging spaced apart movable relation, as shown. The force
transmitting members cross intermediate their upper and lower
arcuate sections at a point 56 substantially coinciding with axis
S--S.
The configuration of the device thus defined when unstressed can be
seen to markedly resemble the contour of a numeral 8, unclosed at
the top, whose overlapping members 50, 51 intersect almost
tangentially and are free to slide past one another in any
direction and to independently withstand deformations due to their
plasticity. The overhanging terminal portions of arms 50 and 51 are
normally spaced apart as shown when the device is unstressed and
curve slightly inwardly toward the open center of the upper section
of the device away from the sensitive zones of the cornua.
The outer contour of the device can be characterized as having
upper and lower pairs of wall bearing lobes formed by the arcuate
sections of the force transmitting arms 50, 51 which are laterally
disposed in symmetrical relation with respect to axis S--S to
define two transverse axes T--T and M--M. The cross-bar sections of
the arms 50, 51 serve to interconnect in force transmitting
relation diagonally opposed upper and lower lobes to provide
contralateral transmission and diffusion of the forces exerted on
the lobe regions by the uterine walls.
The spring-hinge means 57 preferably comprises a filamentary
extension of the force transmitting members 50, 51 having the form
of an inverted V expansion joint having an apex substantially
coincident with axis S--S, as illustrated. The spring-hinge joint
serves, in accordance with the invention, as the source of spring
energy to the force transmitting members 50, 51 resiliently
resisting compression of the members towards the longitudinal axis
S--S when under stress of uterine contractions. The ability of the
device to resist contraction under such conditions is an important
feature of the invention as will hereinafter more fully appear.
In accordance with a further feature of the invention, the device
is provided with withdrawal means for deactuating the spring-hinge
joint 57 to permit the device to be contracted towards its
longitudinal axis S--S in order to facilitate withdrawal. As
presently illustrated, the withdrawal means comprises zones of
weakness 58 and 59 (See FIG. 8) formed in the filamentary structure
at the junctions of the members 50 and 51 with the base of joint
57, and a monofilament 60 affixed to the apex of joint 57 by
suitable means such as by ring 61. By simply pulling with
sufficient force on filament 60, which is adapted to be externally
accessible through the cervical canal, the zones of weakness can be
sufficiently stressed, as lower arcuate lobe forming sections 54,
55 press against the uterine walls, to cause joint 57 to invert
thereby losing its spring energy and permitting the device to be
readily contracted.
Dimensions for parous cavities should preferably not exceed 25
millimeters when the device is unstressed along its longitudinal
axis S--S and 24 millimeters at its upper major transverse axis
T--T. (See FIG. 8) More preferably, the geometry of the device
should obey a number of constant ratios for optimal results. The
spacing between upper arcuate arm sections 52 and 53 should be
substantially greater and ideally on the order of 1 1/2 times
greater than the spacing between lower arcuate sections 54 and 55,
while the overlapping force transmitting arms should cross at
substantially the midpoint of the device when measured along
longitudinal axis S--S. In addition, the angle between the tangents
taken on the two intersecting arms 50 and 51 at the point of
intersection 56 denoted as angle .alpha. in FIG. 3 should
preferably not exceed 30.degree..
The importance of these dimensional parameters can best be
understood in light of the theoretical considerations underlying
the invention and the manner in which the device reacts to
intrauterine contractions to avoid spontaneous expulsion.
The muscular structure of the uterus follows the configuration of
its pear-like shape. As diagrammatically represented in FIG. 1, the
concentric pattern of cross-laid muscular fibers assumes from the
top to the mid-section of the uterus a direction generally inclined
at a 45.degree. angle. From the mid-section down to the isthmus,
the inclination of the muscular fibers becomes progressively less
angulated to a point where the muscles form horizontal rings from
the level of the isthmus down to the cervix.
Thus, the muscular dynamics of the uterus can be reduced for
practical purposes to two major centers of concentric forces as
shown in the planar representation of FIG. 2:
first, two cross-lines of forces intersecting at a 90.degree. angle
and extending from the cornua down to about the mid-portion of the
uterus, and
second, a series of minor lines of forces generated by the ring
muscles encircling the cervial canal.
However, the uterine muscular structure is so dense that it can
produce on stimulation an almost infinite variety of deformations
of the uterine cavity. Taking into consideration the classic
segments of the uterus, contractions can originate at three levels:
at the level of the fundus in one or both cornua regions, at the
mid-uterus, or at the isthmus which for practical and functional
reasons will hereinafter be referred to as the area of the internal
os.
Contractions starting in a circular fashion at the level of one of
the cornua regions will cause distortion of the cavity with a
resulting contralateral and diagonally downward displacement of any
uterine content. A bilateral or in toto fundal contraction will
produce with or without dilation of the uterine mid-portion or of
the internal os area, a remarkable reduction in size of the volume
of the uterine cavity placed just above and just below the tubal
insertion with the displacement of any uterine content almost
vertically downward. A separate, almost horizontal contraction at
the mid-portion of the uterus will tend to deform the cavity in the
shape of an hour-glass acting as an ejecting force against any
uterine content that offers resistance at that level. A contraction
at the level of the internal os and, for that matter, at the level
of the isthmus, can produce a dual effect: a restrictive distortion
of the lower part of the uterus and, possibly simultaneously, a
widening in the diameter of the internal os with a resultant
downward ejection reaction.
In any event, the essential aspect to consider is that these
various forms of contractions seem to originate chiefly at the
level of the cornua and in the particularly sensitive area of the
internal os. Considering further that the volumetric dimensions of
the uterine cavity are far from being static but vary with the
different phases of the menstrual cycle, we are led to believe that
any intrauterine device primarily designed to exert pressure on the
periphery of the uterine cavity or to resist compression from the
uterine walls in order to resist expulsion is unphysiological. In
addition, the foregoing suggests that the configuration of any such
device should be such as to avoid stimulating the sensitive
contraction triggering points of the cornua and of the internal os
by evading contact with these areas as much as can practicably be
done.
In accordance with the invention, prevention of expulsion is
accomplished in three separate ways: minimal contact of the device
with uterine walls, compressibility of the device, and
contralateral transmission and diffusion of uterine contraction
forces.
The size of the device is not intended to cover the entire
periphery of the uterine cavity, least of it the area of the
internal os, where unwanted stimulations associated with pain and
bleeding would necessarily be generated. Rather, the device is
designed to fit in the middle section of the uterine cavity where
fecundated ova tend to implant themselves most frequently and to
stay away from the contraction triggering zones of the cornua, the
area of the internal os and the extreme lateral ends of the uterine
cavity.
To that effect, the curvature of the overhanging terminal portions
of arms 50 and 51 is smooth and oriented inward, away from both
cornua: the 24 millimeter width of the device along its major
transverse axis T--T can be comfortably accommodated by most
uterine cavities whose average width from cornu to cornu is in the
extremity of 33 millimeters while the lowermost extremtity of the
device lies at least 10 millimeters substantially above the average
level of the internal os.
In the event of minor uterine contractions, the device first acts
like a cushioning spring and absorbs the initial shock from the
uterine walls at its four lobate regions defined by the transverse
axes T--T and M--M. Contraction forces may then cause the device to
constrict and to adapt itself to the restricted dimensions of the
uterine cavity, particularly in its uppermost transverse plane
where the upper overhanging arcuate sections 52, 53 can
simultaneously fold inward toward the open center of the device and
overlap each other, depending upon the direction of the
contractions (See FIG. 4).
As a whole, the structural design of the device is such that its
original geometry can ultimately withstand a total size reduction
in the order of 40 percent and spring back to its normal shape once
uterine contractions cease. In accordance with the principles
enunciated above, this device is primarily designed not to fight
against the physiology of the uterus but to conform to it.
In case of strong contractions, as can happen during menstruation,
the device utilizing uterine muscular forces will anchor itself
against the walls of the uterine cavity in order to keep from being
expelled. The anchoring effect is achieved through the cross-bar
relationship of the force transmitting arms 50, 51 whereby the
multi-directional forces exerted by the uterine walls against one
or both sides of the device are transmitted and diffused
contralaterally to the opposite sides.
Referring to FIGS. 4-7 inclusive to illustrate, a bilateral
contraction exerted at the level of the fundus causes the upper
arcuate sections 52 and 53 to be compressed inwardly with the
forces being transmitted contralaterally to the lower diagonally
opposed arcuate sections 54 and 55 respectively, as shown in FIG.
5. As a result, the lower arcuate sections 54 and 55 bulge
outwardly resisting downward displacement toward the area of the
internal os. Should the contractions occur at the mid-section of
the uterus, the reverse occurs: sections 54 and 55 are compressed
inwardly while their corresponding diagonally opposed arcuate
sections 52 and 53 expand and anchor themselves in the upper part
of the uterine cavity. Muscular forces generated by a partial
contraction at the level of the fundus and acting unilaterally on
the upper arcuate section 52 of arm 50 (See FIG. 6) are entirely
directed toward lower arcuate section 54 of arm 50 causing the
device to deform and tilt on its longitudinal axis S--S and to
subsequently diffuse some of the forces to arm 51 whose upper
aruate section 53 tends to anchor itself up with an ascending
motion. In the remote event that the uterine contractions force the
device in an upside-down position as shown in FIG. 7, the
structural design is such that the cross-bar mechanism can still
operate effectively and prevent the device from engaging into the
area of the internal os as well as from being expelled.
In order to increase the adherence and anchoring ability of the
device against the uterine walls, minute knurl-forming
protuberances such as hereinafter described can be formed in the
outer lobate wall bearing surfaces of the four arcuate sections of
the device.
On the basis of the foregoing, the importance of the interaction
between the shape and the dimensions of the device can be
appreciated: the spring-hinge joint 57 acts as a fulcrum permitting
each force transmitting member to react independently whereby
forces are diffused to the points of least resistance through the
device. In turn, this spring-hinge mechanism constitutes an
important complement to the cross-bar mechanism of the members, the
effectiveness of which is directly related to the amount of
built-in leverage available.
In order that the force transmitting arms 50 and 51 can develop
sufficient torque to properly transmit and direct forces against
the uterine walls, the dimensional and geometric parameters
hereinabove described should be followed.
It is to be appreciated that the invention in its broad aspects is
not limited to the figure 8 configuration herein illustrated and
described, but the cross-bar mechanism and its advantages can be
achieved in accordance with the invention by any other suitable
configuration and orientation.
A preferred embodiment of the invention is illustrated in FIGS.
8-12. In the preferred form illustrated, the plastic body of the
device comprises a substantially filamentary structural frame 62
describing the basic geometrical configuration illustrated in FIG.
3 and constituting the areas of maximum cross-section of the
device, and membrane means is integrally formed with the frame to
provide substantial surface contact with the endometrium.
While the cross-section of the frame 62 varies according to the
specific functions to be performed by its various segments, in
general, the cross-section is preferably ovoid having a major axis
in the plane of the device which is greatest at the overlapping
sections of the members 50, 51.
Since the main function of the cross-bar mechanism of members 50
and 51 is to transmit contraction forces, the major cross-sectional
axis of the frame is at its greatest in this region to provide
structural strength. In order to keep the bulk of the device down
as much as possible to avoid bleeding and discomfort, the frame in
this region is also substantially flattened. (See FIGS. 9 and 13)
Moving upwardly towards the terminal portions of upper arcuate
sections 52, 53 where flexibility is required, the shape of the
frame gradually takes on a more rounded cross-section and the major
cross-sectional axis lying in the plane of the device undergoes a
progressive diminution (See FIGS. 10 and 11). Similarly, the frame
progressively regains an ovoidal section and undergoes a slight
reduction in its major axis in the lower arcuate sections 54, 55 in
a direction towards their terminal portions (See FIG. 12). At
junctions 58 and 59 at the base of spring-hinge joint 57, the frame
illustratively undergoes a major decrease in section to form zones
of weakness so that the joint can be readily inverted prior to
removal of the device as will hereinafter be described. The optimum
cross-sectional shape and dimensions of the frame can be determined
through use, as will also be the case with the geometrical
parameters of the inverted-V joint 57.
An important feature of the invention resides in the provision of
plastic inwardly deformable membranous regions which are
strategically located so as to maximize contact with the
endometrium without interfering with the dynamic mechanism and
flexural ability of the device and without creating sources of pain
and bleeding.
It has been empirically verified that the extent of surface contact
with the endometrium is directly related to low pregnancy rate. At
this state of the art, the exact contraceptive process involved is
still a matter of conjecture but, on the basis of recent
investigations, the most probable reason appears to be the
accumulation of macrophages around the surfaces of the device.
Thus, the greater the endometrial area covered, the larger the
accumulation of macrophages and the lower the probability of
conception. In order to maximize their effectiveness, this
accumulation of macrophages should preferably be made to occur at
the level of the fundus as well as in the mid-uterine area wherein
implantation takes place most frequently.
To that end, the body of the device is preferably formed as
illustrated in FIG. 8 with thin pliable plastic membrane-like
regions operatively associated with the structural frame at the
overhanging terminal portions of the upper arcuate sections 52 and
53, at their mid-sections in the region of overlap and at their
lower arcuate sections 54 and 55.
Referring specifically to FIG. 8, a pair of elliptically shaped
membranous regions 63 and 64 extend inwardly from the overhanging
terminal portions of upper arcuate sections 52 and 53 where they
are free to bend downwardly toward the open center of the device in
the event of fundal contractions. The membranous regions 63 and 64
are formed with two similarly located pin engaging openings 65 and
66 respectively which can be reinforced as shown. Openings 65 and
66 comprise the means in conjunction with ring 61 at the apex of
joint 57 by which the device is releasably secured in a contracted
state onto a suitable introducer implement for and during insertion
into the uterus, all of which is hereinafter described.
FIGS. 10 and 10A illustrate two possible cross-sectional forms that
membranous regions 63, 64 can take. In FIG. 10, the membrane
structure is substantially uniform in cross-section from a narrowed
neck 67 at its junction with frome 62 to its free edge.
Alternatively, FIG. 10A shows a membrane section which gradually
diminishes in thickness. In any event, the membrane regions should
be formed so that they do not interfere with the ability of the
upper arcuate arm sections to flex downwardly under fundal
contractions.
Referring to FIG. 8 and FIG. 13, a second set of membranous areas
68 and 69 illustratively extend from the opposite sides of member
51 substantially above and below its region of overlap with the
opposite member 50. Upper membrane area 68 extends from the inner
surface of upper arcuate arm section 53 substantially at the
transverse axis T--T and gradually increases in width as it
approximates the curvature of the frame until it reaches the
overlapping cross-bar region where it is at a maximum, and then
tapers down until its point of termination on the outer surface of
lower arcuate section 55 somewhat above transverse axis M1--M.
Lower membrane area 69, which extends in the opposite direction to
membrane area 68, has a similar tapered configuration as it follows
the contour of the frame from the outer surface of upper arcuate
section 53 to traverse substantially the entire inner extent of
lower arcuate section 55 terminating close to spring-hinge joint
57.
FIGS. 9 and 13 illustrate one possible cross-sectional shape that
the membrane areas 68 and 69 can take. As in FIG. 10A, the membrane
structures are tapered from their junctions with the central frame
member 62 with which they are integrally formed.
Still referring to FIG. 8, the crescent-shaped membranous area 70
is located at the inner surface of lower arcuate section 54. The
lower terminal point of this membrane region is located similarly
to that of the opposed membrane area 69, being in a substantially
proximal relation to the spring-hinge joint 57, whereas its upper
terminal point is located just about where the membranous area 69
crosses over arm 50 below the mid-point of intersection 56.
The cross-section of the membrane area 70 can, as in the case of
membrane areas 63, 64 illustrated in FIGS. 10 and 10A, take on a
uniform thickness from a narrowed neck 71 junction with frame
member 62 as in FIG. 12, or can have a tapered configuration as in
FIG. 12A. Again, the primary consideration is that the membranous
structures are inwardly compressible upon themselves so as not to
interfere with the ability of the plastic body to flex and
conformably engage the uterine walls in response to
contractions.
An alternate embodiment having a different membranous configuration
is illustrated in FIG. 14. As shown therein, the crescent-shaped
membranous region 70 is greater in area than its counterpart in
FIG. 8, as is also true with the lower portion of membrane 69
extending from arcuate arm section 55. In addition, membrane region
70 extends upwardly substantially higher than in FIG. 8 to a point
above the mid-point of intersection 56, the purpose being to
increase the total surface area available for contact with the
endometrium.
Due to their relative thinness and their locations, the membranous
regions above described should not materially affect the
flexibility of the plastic body or the ability of the frame to
transmit contraction forces.
It should be evident that the foregoing description pertains to the
most likely configuration of membranous regions, and variations
therefrom to provide increased surface area are within the scope of
the invention so long as the flexibility and contractability of the
device are not materially affected.
In accordance with a further aspect of the invention, pluralities
of substantially regularly distributed minute surface
irregularities, or what can be called asperities 72, are preferably
formed in the membrane surfaces front and back substantially across
their entire extent. The asperities provide an extremely slight
controlled degree of irritation over the surface of the endometrium
which should result in an increased presence of phagocytic cells in
the uterine cavity and a consequent further reduction in the
incidence of pregnancy.
The key features of these asperities are twofold and equally
important. comprising other for
First, they are minute in terms of height and width as their
dimensions are not likely to exceed fractions of a millimeter
and,
Second, their profile must avoid any sharp, rough or jagged edges
which, no matter how small, could possibly cause bleeding.
As long as these two criteria are met, the shape of the asperities
can assume any number of basic designs such as circles, ridges and
grids, stars, crosses, mounds or peaks and the like, as shown in
FIG. 19.
In accordance with a further feature of the invention, the outer
lobate wall bearing surfaces of the four arcuate sections of the
force transmitting members are preferably formed at and adjacent
the transverse axes T--T and M--M with pluralities of low profile
protuberances 73 to create knurled gripping surfaces.
The knurl-forming protuberances have a dual purpose: to increase
the stability of the device and prevent its migration in the
uterine cavity and to enhance the ability of the frame to anchor
against the uterine walls in case of strong uterine contractions so
that the device can better resist being pushed down toward the area
of the internal os.
To illustrate and referring again to FIG. 5, under a bilateral
contraction at the level of the fundus, the device will transmit
forces contralaterally via its cross-bar mechanism causing the
lower arcuate sections 54, 55 to expand outwardly against the
uterine walls. Conversely, contractions at the level of the
mid-uterus will compress arcuate segments 54 and 55 which, in turn,
will cause the upper arcuate sections 52, 53 to expand outwardly
and to anchor themselves in the upper portion of the cavity. To
maximize their gripping ability, the knurl-forming protuberances
are deployed at the four lateral lobate regions where contraction
forces tend to exert most of their thrust.
The actuator contour of the protuberances 73 is not limited to any
particular shape and, as is illustrated in FIGS. 15-18, they can be
embodied in any number of suitable shapes. For example, rows of
thin pliable fins of rounded contour extending from the frame 62 a
few millimeters as shown in FIGS. 11, 12, and 12A can be employed,
as can a series of saw tooth notches or indentations in the frame
itself as in FIGS. 16 and 18. Whatever their precise shape, it is
important that the protruberances 73 define a low profile having a
substantially non-jagged edge to avoid injury without sacrificing
gripping ability.
Recent clinical investigations of the use of metallic copper as an
adjunct to intrauterine contraceptive devices have yielded
promising results, although it is too early to pass any definite
judgement on the long term effects of copper on the
endometrium.
In the event that such an adjunct is found to be desirable, a
device in accordance with the present invention would be wholly
compatible with the use of copper or any other metal, compound or
bicomponent able to duplicate the anti-fertility mechanicm of
copper which has yet to be precisely determined. Should the ionic
or electrical properties of copper be largely responsible for such
mechanism, other metals could conceivably include silver, gold or
any other metal of low electrical resistivity.
The membrane surfaces of the device would provide a convenient
carrier for the metals which, if in wire form, can readily be
stitched into the thin plastic membranes or, if in ultra-thin plate
form, can be tacked onto both surfaces of the membrane structure
and interconnected. Still, among other possibilities, the entire
device or parts thereof could be coated with a metallic film which
would not affect its flexibility.
The device can be constructed from a wide variety of synthetic
polymer resins such as polyethylene, polypropylene, nylon,
polyester or teflon among others, or any other suitable resilient
material proven to be non-allergenic and inert to human body
tissue. Preferably, the material should have good molding
properties and be suitable for injection molding. Although one
single polymeric component is seen as preferable for the device, a
bicomponent can also be used such as an inner core of polyester
coated with teflon or silicon or even an inner frame of metal such
as stainless steel or a high molecular memory alloy such as nitinol
covered with a polymer. In any event, since the position of the
device in the uterine cavity may in some cases have to be checked,
any of the well-known radiopaque substances such as a barium
sulphate can be added to the resin.
As indicated, the device can be made by molding or by any other
suitable forming process.
Referring to FIGS. 20-23, removal of the device from the uterine
cavity is easily accomplished by the physician and with a minimum
of discomfort for the user, the key procedural step consisting of
deactuating the spring-hinge joint 57. Referring specifically to
FIG. 20, the physician first pulls monofilament 60 connected to the
apex of V joint 57 which should be adapted to be easily externally
accessible through the cervical canal. With the lower arcuate
sections 54 and 55 of the force transmitting members pressing
against the walls of the uterine cavity, a sufficient downward pull
causes the lower arcuate sections to spread apart and the expansion
V joint 57 to pivot downwardly about its zones of weakness 58 and
59. As soon as the V joint is inverted, the source of spring energy
to the force transmitting members 50 and 51 is deactuated and the
force transmitting members offer a minimum resistance to further
pulling.
Channelled by the narrowing walls of the uterine cavity, further
downward force exerted on the filament causes the joint 57 to
elongate (FIG. 21) and, in turn, forces the collapse of the entire
bottom section of the device whereby the lower arcuate arm sections
54, 55 are forced to assume a parallel arrangement with respect to
longitudinal axis S--S. The elongated shape and rounded contour
taken by the V joint is quite important in that it progressively
opens the cervical canal and dilates it to facilitate the outward
passage of the device.
In the following FIGS. 22 and 23, the force transmitting members
50, 51 along their entire extent are shown reduced to a fully
parallel arrangement, thus presenting a minimum of surface
resistance to their introduction in and passage through the
cervical canal.
As has already been stated above, the procedure and means for
inserting the contraceptive device into the uterus must insure
against perforation of the uterine wall. In addition, the
introduction of the device should be a painless procedure and one
which is easy and relatively fast to accomplish even by paramedical
personnel after only a brief period of orientation and training. In
accordance with a further aspect of the invention, an introducer
implement is provided which meets these requirements and which
constitutes a major departure from the prevalently used cannulae or
tubes, although the latter can be used if so desired.
Referring to FIGS. 24 and 25, the introducer comprises a
cylindrical shaft 74 of bilogically inert and relatively stiff
material having a curvilinear profile with a handle 75 formed in
one end and means comprisin a rectilinear shaft section 76 formed
in the othe end of releasably holding a contraceptive device 77 of
the type herein illustrated and described in proper orientation and
contracted condition for passage into the uterine cavity.
The handle illustratively comprises a flattened section of the
shaft at the end preferably having a knurled surface 78 to
facilitate gripping. As illustrated in FIG. 26, the handle is
designed to be held by the user between thumb and index finger and
can be suitably contoured with a widened area at its junction with
the bowed portion of the shaft, as shown, to maximize surface
contact with the thumb to facilitate control and manipulation of
the implement during insertion.
An important feature of the introducer resides in its curvilinear
profile illustrated in FIGS. 24 and 26. As shown, the shaft 74
describes a curve which angles downwardly from its end having the
handle 75 to an intermediate point on the shaft where it reverses
its direction of curvature. The effect created by this double
reverse curvature of the shaft is that the rectilinear section of
the shaft 76 holding the contraceptive device extends in axially
offset substantially parallel relation with the handle 75 of the
implement.
As can best be seen in FIG. 26, the curvature of the shaft in the
region of the device holding section 76 conforms to the general
angulation of the longitudinal section of the uterine cavity when
the patient is properly positioned on the examining table, while
the reverse curvature at the opposite end near the handle 75 should
be such as to prevent the fingers from interfering with the
physician's line of vision and also to permit the forward end of
the introducer to be lowered in a way that the obstacle of the
perineum is overcome.
Referring again to FIG. 24, the angle .beta. formed between the
axis of the rectilinear section 76 of the shaft and the tangent to
the shaft drawn from the handle extremity at the opposite end
should be substantially similar to the angle .theta. formed between
the horizontal and the tangent to the shaft drawn from the forward
extremity of the shaft. Both angles should preferably range between
about 15.degree. and 25.degree., primarily to conform to the
angulation of the uterine cavity.
Both angles being equal or substantially equal permits the forward
forces exerted on the shaft at the handle end by the user to be
transmitted on a parallel plane to the forward end of the shaft
holding the device with little or no loss of force. This provides
greater sensitivity to the hand and better judgement as to the
amount of force to be applied, which is particularly important in
cases of unrecognized retroflexed uteri assuring greater safety
against perforation.
Another important feature of the invention assuring against
perforation of the fundus are the groups of thin annular bands 79,
80 and 81 formed on the shaft which provide a means fo gauging the
depth reached by the forward end of the introducer in the uterus.
The three reference levels can for illustration be spaced one
centimeter apart representing the 5, 6 and 7 centimeter marks
measured from the tip of the forward end 76.
As can be seen, the first or 5 centimeter reference leve 79 is
represented by a single band, the second or 6 centimeter level 80
by two spaced apart bands and the third or 7 centimeter level 81 by
an arrangement of three bands. These illustrative dimensions have
been empirically determined and should cover the full range of
uterine depths from the external cervical os to the fundus. The
sequential groups of bands where each succeeding group has an
additional band is judged preferable over numbers imprinted on the
introducer which are sometimes used but difficult to decipher
during insertion of the device.
Preferably, the bands are in a color providing a sharp contrast
with the color of the shaft and readily distinguishable from the
color environment of the vaginal walls. By way of example, bright
green colored bands on a white introducer shaft should provide the
contrast desired.
A final safeguard against perforation of the fundus are the flanges
82 preferably formed on the shaft 8 centimeters from the tip of the
forward end 76. Flanges 82 prevent the introducer from being pushed
into the uterus any deeper, although a uterine cavity of such depth
is rather rare.
The introducer shaft 74 is preferably circular in cross-section
intermediate its ends and is formed with segments 83 and 84 of
different diameter for reasons of structural strength. Segment 83
which extends from the rectilinear section of the shaft 76 to the
flanges 82 can illustratively have a diameter in the order of 4
millimeters. Segment 84, which illustratively can be 5 millimeters
in diameter, extends from flanges 82 to the junction with handle
75. This stepped increase in diameter is intended to provide
sufficient strength in the major portion of the shaft to withstand
the force necessary for the introduction of the device and at the
same time to provide a certain degree of desired flexibility in the
similar portion of th shaft in the region to be inserted.
Illustrative of suitable overall shaft dimensions are the
following:
x .apprxeq. 1.7 cm.
y .apprxeq. 7.5 cm.
z .apprxeq. 26 cm.
In accordance with the invention, reference being had to FIGS.
29-31 in particular, the means for releasably holding the
contraceptive device 77 comprises a cavity formed in the
rectilinear shaft section 76 having a substantially flat back
support wall 85, and two end walls 86 and 87, the cavity being open
on the sides. As can readily be seen, the length and profile of the
cavity are contoured to conform to the shape of the device 77 when
held in contracted condition for insertion, the back wall having a
recessed area 88 substantially midway between end walls 86, 87 to
accommodate the double thickness of the overlapped force
transmitting arms 50, 51 to avoid any potentially harmful
protrusion.
In accordance with the invention, locating pin means operatively
associated with the cavity is provided for cooperating with the pin
engaging openings formed in the device 77 to releasably position
the device for insertion. In the illustrative embodiment of FIGS.
29-31, two locating pins 89 and 90 depend substantially
perpendicularly from back wall 85 into the cavity. Pins 89 and 90
are situated on the axis of the shaft and are spaced apart, as
shown, to cooperate with the pin engaging openings 65 and 66 of the
upper arms of the device 77 and with the pin engaging opening in
ring 61 at the apex of joint 57 in the lower portion of the
device.
As is clearly shown in FIG. 31, the devic 77 is releasably mounted
on the introducer in a contracted condition with its normally
movable force transmitting members 59 and 51 held in fixed relation
and its longitudinal axis S--S parallel to the axis of the shaft
74. The rear locating pin 89 is disposed within and extends through
the ring 61 thereby releasably engaging the lower end of the
device. The upper end of the device is similarly releasably engaged
by forward locating pin 90 which is disposed within and extends
through the openings formed in the upper membrane regions 63 and
64, the upper arcuate sections of arms 50 and 51 being contracted
so that the membrane regions 63 and 64 are overlapped with their
pin engaging openings superimposed.
Preferably, the locating pins 89 and 90 are axially spaced apart so
that the device when thus engaged is also compressed along its
longitudinal axis S--S, the overall length of the compressed device
being reduced by a few millimeters from its unstressed dimension.
As will hereinafter become apparent, this constitutes an important
safety factor against fundal perforation.
In the embodiment of FIGS. 29-31, the locating pins 89 and 90 are
designed to have a force fit engagement with their cooperating pin
engaging openings in the device 77. As can be seen, each pin is
shaped with a rounded enlarged terminus and a tapered stem.
An additional feature of the introducer is the bulbous searching
head 91 formed in the forward or leading end of the shaft.
Extending out front of the leading edges of the device 77 by a few
millimeters, it performs during insertion the triple function of
dilating the narrow lumen of the cervical canal, of deflecting some
of the stress exerted onto the leading edges of the device and,
most importantly, of serving as a guide to the physician in the
initial portion of the cervical canal which is lined with the
glandular cavities of the arbor vitae (See FIG. 26). If the forward
tip of the introducer were too sharp, one of these cavities could
be mistaken for the cervical canal leading to possible uterine
perforation.
Illustrated in FIGS. 32-34 is an introducer having an alternate
configuration in accordance with the invention, FIG. 45
illustrating alternate membrane opening locations suitable for use
therewith. As shown, the introducer of FIG. 32 differs from that of
FIG. 29 in two respects.
In order to minimize the length of the implement, the searching
head 92 while retaining a bulbous configuration is modified so that
the forward end of the contracted contraceptive device 77 is
exposed, the cavity formed in the shaft 74 having only a rear end
wall 87 and no front end wall. To compensate for the increased
stress exerted on the leading edges of the arcuate arms of the
device, the pin engaging openings 65 and 66 in the membrane regions
63 and 64 are located at the junctions of the membranes with the
frame 62 as shown in FIG. 45. Engagement with the locating pin 93,
illustratively having a modified shape from the corresponding pin
90 of FIG. 29, thus occurs at the very edge of the structural frame
62 imparting greater strength and resistance to distortion than
would be the case if the opening locations were as shown in FIG.
31.
It should, of course, be understood that the locating pins can have
a variety of force fit shapes such as shown in FIGS. 35 and 36, and
can have a hook or clamp configuration such as shown in FIG. 37 and
embodied in the introducer of FIGS. 38-40. The introducer shown in
FIGS. 38-40, adapted for use with a membrane opening configuration
such as in FIG. 45, constitutes still another possible variation to
that of FIGS. 29-31 within the scope of the invention.
As best illustrated in FIG. 38, there is provided a bulbous
searching head 94 having a forward contour substantially similar to
that of head 91 of FIG. 29. As contradistinguished from the
embodiment of FIG. 32, the cavity formed in the linear section 76
of the shaft of FIG. 38 has both a rear end wall 87 and a forward
end wall 95 formed by the searching head 94. The locating pin means
for releasably engaging the contraceptive device comprises a pair
of mirror-image hook shaped rear locating pins 96 and 97
cooperating to form a spring-like two prong clamp, and a forward
hook shaped locating pin 98 similarly cooperating with the
searching head 94 which can be seen to have a hooklike
configuration as well.
Yet another introducer embodying the principles of the invention is
illustrated in FIGS. 41-44. This type of introducer differs
markedly from the other three embodiments herein disclosed. As
illustrated, the linear section 76 is formed with a pair of
cavities on opposite sides of the shaft. The lower cavity having a
substantially flat rear support wall 99 and two end walls 100 and
101 differs from the similarly located cavities of the other
illustrative embodiments in that it is shallower and does not have
a recessed area designated 88 in FIGS. 29, 32 and 38. The upper
cavity, which is substantially of the same depth but substantially
shorter in length than the lower cavity, has a flat rear wall 102
and two end walls 103 and 104.
The lower cavity has locating pin means 105 and 106 depending from
rear wall 99, pin means 106 comprising three locating pins in the
nature of a triple prong clamp, as shown. The upper cavity has a
single locating pin 107 substantially coaxially aligned with pin
105 of the lower cavity. As can be seen, the searching head 108 has
a bulbous contour similar to the contour of head 91 of the
embodiment of FIG. 29.
The contraceptive device 77 is affixed to the introducer in a
manner different from that previously described. The device is
mounted with its force transmitting members 50 and 51 disposed in
different planes, member 50 being disposed in the lower cavity and
engaged by locating pin 105 and member 51 being bent around the
shaft and disposed in the upper cavity engaging locating pin 107.
The ring 61 located at the lower axial end of the device is
disposed in the lower cavity in the same plane as member 50 and is
held by pin means 106.
It is preferred that the device and introducer be sold fully
assembled and prepackaged in a sterilized condition. Referring to
FIG. 46, the package can comprise a transparent heat-sealable
plastic casing 109 of rectangular configuration and having a
removable cardboard base 110. Illustratively, the base is provided
with two rows of perforations running along its entire length. One
end of the base can be made to extend beyond the edge of the
enclosure to provide a pull tab. With such a construction, the base
can be readily removed providing access to the contents.
Although the foregoing implies that the device is mounted in its
contracted condition on the introducer ready for insertion,
alternatively the device may come attached only via its lower ring
61 with the upper arcuate arms in their relaxed extended position.
This may be desirable in the event that a synthetic resin of low
resilience and weak molecular memory is used to injection-mold the
device. In such case, the physician need only bend the upper
arcuate arm sections of the device so that their membrane openings
superimpose and then snap them onto the forward locating pin of the
introducer. Of course, sterile gloves will be used during
assembly.
Insertion of the device is relatively simple. Referring back to
FIG. 26, the bulbous forward end of the introducer shaft is gently
inserted into the cerival os with the device disposed downwardly
and is slowly advanced through the cervical canal until a definite
snap is felt through the introducer shaft. This snap occurs shortly
after the device, constricted during passage through the narrow
cervical canal, has passed through the constrictive ring formed by
the internal os where it expands back to its normal contracted
condition as mounted on the introducer. At this point, the device
is ready to be released.
It should be apparent that by virtue of its pliability the device
upon entering the narrow cervical canal can be simultaneously
squeezed inwardly and elongated reducing its resistance and
permitting easy insertion. In the event that any partially inserted
device has to be withdrawn, the locating pins are such that the
device will remain attached to the introducer and, therefore,
safely retrievable even though resistance is met by the lower edges
of the device.
The release technique can best be understood by reference to FIGS.
27 and 28. In its normal state, the uterine cavity has the form of
a flat, collapsed envelope. When an object is introduced therein,
the muscular layers will "give" but will nevertheless stay in close
contact with the object due to their tight elasticity. Thus, the
uterine walls exert a certain amount of pressure onto the surface
of the device shown ready for release in FIG. 27 preventing it from
being rotated about its longitudinal axis which extends
perpendicularly to the plane of FIG. 27.
To release the device, the introducer is rotated until the force
exerted by the uterine walls on the device causes the locating pins
to disengage their cooperating pin engaging openings. Thus
disengaged, the spring-hinge joint 57 causes the force transmitting
members of the device to spring back to their normal extended
configuration represented in FIG. 28. As shown in FIG. 28, the
device is held in close contact by the surfaces of the endometrium
112 without contacting the extreme lateral ends of the cavity.
The relative position of the searching head 91 with respect to the
fundus at the point of release is illustrated in FIG. 26. Since the
overall length of the device is 25 millimeters for parous (20
millimeters for nulli-parous), the total extent of the introducer
engaged in the uterus will very rarely exceed 60 millimeters in
parous and 55 millimeters in nulli-parous women. These depth levels
are at least 10 millimeters below the normal level of the fundus so
that there is no fundal contact during insertion. This represents a
major safety factor assuring in conjunction with the bulbous
searching head and depth control bands on the shaft that fundal
perforation will not occur.
The relationships between the various physical features of the
device embodying the present invention and the four major uterine
physiological effects mentioned earlier can be summarized in
tabular form where a plus sign indicates an increase as a function
of a physical factor, a minus sign a decrease and a zero, no
significant change.
Physiological Effects Physical Features Pain Bleed- Expul- Preg-
ing sion nancy Size - - - - Shape - - - 0 Membranes 0 0 0 -
Asperities 0 0 0 - Contralateral - - - 0 Force Distrib. (Cross-bar
Mechanism) Knurled Lobate 0 0 - - Surfaces
Thus, based on theoretical considerations, reduction in pregnancy
rate in the present device is seen to be primarily due to the
irritation generated by the membrane surfaces and their minute
asperities while the size of the device and the knurled lobate
regions can be regarded as ancillary factors since both features
essentially contribute to keeping the device in the strategic
implantation ground of the middle portion of the uterine cavity.
And whereas the size, shape, cross-bar mechanism and lobate regions
of the device should result in a measurably lower expulsion rate
than has previously been attainable, these physical elements are
also seen for the most part to reduce pain and bleeding, or at
worst to cause no significant change, since they are designed to
conform to the uterine physiology.
* * * * *