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BACKGROUND OF THE INVENTION
The present invention relates to implants to be situated in the vas
deferentia of adult male animals for the purpose of controlling
conception.
Implants of this type are generally know. For example, such implants are
capable of blocking the flow of fluid through a vas deferens in order to
prevent conception, and of course there are known implants which can be
placed in a position which will again permit fluid to flow through a vas
deferens to that it is possible in this way to achieve reversible
contraception, with the capability of conceiving being restored when
desired.
However, the problem with implants of the above general type is that they
operate, when preventing conception, by completely blocking the flow of
fluid through a vas deferens. Such complete blockage of the flow of fluid
is highly undesirable. Thus, the preventing of sperm flow is undesirably
accompanied by preventing of flow of the fluid which carries the sperm,
and thus beneficial effects resulting from the flow of this latter fluid
are prevented with conventional implants as referred to above. The fluid
which flows through the vas deferens serves not only to carry sperm but
also to perform other functions such as supplying certain hormones and
enzymes to the body, maintaining the lumen of the vas deferens in an open
condition enabling fluid to flow properly therethrough, and avoiding
undesirable build-up of pressure. Moreover, with complete blockage of flow
through the vas deferens there is a tendency for the latter to close upon
itself downstream of the implant, so that when flow is restored with
conventional implants there is still difficulty in achieving reliable flow
of fluid through the vas deferens, particularly if the latter has been
completely closed over a long period of time.
SUMMARY OF THE INVENTION
It is accordingly a primary object of the present invention to provide an
implant which will avoid the above drawbacks. In particular, it is an
object of the present invention to provide an implant which will permit
the fluid which carries the sperm to flow through the vas deferens while
at the same time retaining, when it is desired to prevent conception,
sperm so as to prevent them from being carried along with the fluid, with
the exent to which sperm are retained in this way being sufficiently great
to prevent conception in a highly reliable manner.
It is furthermore an object of the present invention to provide an implant
which can readily be placed in a condition where fluid with sperm therein
can flow freely through the vas deferens so that the capability of
conceiving can be restored very easily and conveniently whenever desired.
It is furthermore an object of the present invention to provide an implant
of the above general type which can be introduced into the vas deferens
without creating undesirable kinks or the like therein which might
undesirably prevent normal fluid flow through the vas deferens.
Also, it is an object of the present invention to provide an implant of the
above general type which is composed of simple rugged elements which can
be conveniently manipulated and which can be situated in the body without
creating any particular discomfort and while being fully compatible with
the body of the individual who receives the implant of the invention.
According to the invention the implant includes a pair of coaxial tubular
means which respectively have inner end regions situated adjacent but
spaced from each other along the common axis of the tubular means, while
the latter also have outer ends distant from and directed away from each
other. An intermediate housing is fluid-tightly connected with the pair of
tubular means at the inner end regions thereof so that the pair of tubular
means can communicate with each other through the space within the
intermediate housing. The intermediate housing has in its interior a
plurality of fine particles which can assume a conception-preventing
position situated in the path of fluid flow between the pair of tubular
means as well as a conception-enabling position situated beyond the path
of fluid flow between the pair of tubular means. These particles are
capable of responding to magnetic forces, and a permanent magnet surrounds
one of the tubular means at its inner end region while being situated at
the exterior of the housing for the purpose of attracting the particles to
their conception-preventing position where the particles are urged toward
each other sufficiently to form a body the density of which is great
enough to prevent sperm from flowing through this body while at the same
time the body is sufficiently porous to permit the fluid which carries the
sperm to flow through the body, so that in this way fluid which normally
carries sperm can flow through the vas deferens while sperm are retained
by the particles which are in their conception-preventing position. The
pair of tubular means respectively carry at their inner end regions a
porous means through which the particles cannot flow but through which the
fluid can flow, so that in this way the particles are retained within the
intermediate housing. When conception is desired the particles are readily
situated beyond the path of flow of fluid between the pair of tubular
means. For example if the particles are of a magnetically soft material
capable of responding to magnetic forces without becoming permanently
magnetized, then it is only necessary to situate adjacent the implant of
the invention a magnet stronger than the above permanent magnet for
attracting the particles away from their conception-preventing position to
their conception-enabling position. Such a magnet which is stronger than
the permanent magnet of the implant of the invention can readily be
situated at the exterior of the body of the individual provided with the
implant, in the region of the scrotum, for example, for the purpose of
attracting the particles to their conception-enabling position. However,
it is also possible to provide a second permanent magnet into the field of
which the particles are transferred away from their conception-preventing
location, so that when in the field of this second magnet they will be
retained thereby in their conception-enabling position. Furthermore it is
possible simply to demagnetize the magnet as well as the particles if they
retain any residual magnetism and permit the latter simply to fall by
gravity to their conception-enabling position.
BRIEF DESCRIPTION OF DRAWINGS
The invention is illustrated by way of example in the accompanying drawings
which form part of this application and in which:
FIG. 1 is a longitudinal sectional elevation of an implant of the
invention, taken in a plane containing the common axis of the pair of
tubular means thereof, with the implant being shown in FIG. 1 enlarged
many times since the distance between the outer tips of the pair of
tubular means in the actual implant is on the order of 1 inch; and
FIG. 2 is a fragmentary sectional elevation showing a central part of an
implant of a construction slightly different from that of FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to FIG. 1 of the drawings, the implant 10 which is
illustrated therein includes a pair of tubular means 12 and 14. The pair
of tubular means 12 and 14 are coaxial, with the tubular means 14 being
situated upstream of the tubular means 12 in that the fluid in the vas
deferens first enters the tubular means 14 and flows along the interior
thereof toward the tubular means 12.
The tubular means 12 has an inner tubular member 16 which carries at its
exterior a tissue-ingrowth means 18 which may be made of any filamentary
material such as gold wire which is wound around and fixed to the exterior
surface of the inner tubular member 16. The inner tubular member 16 is
flexible and extends outwardly beyond the tissue-ingrowth means 18. This
inner tubular member 16 may be made, for example, of a suitable silicone
rubber which is compatible with the body, such as a Silastic type of
material, or the inner tubular member 16 may be made of a metal such as a
suitable stainless steel wire which is coiled and which has its
convolutions engaging each other to form in this way the equivalent of a
flexible metal tube.
The tissue-ingrowth means 18 may be made of gold wire and is shown in an
idealized condition in the drawing. This tissue-ingrowth means 18 is made
of a fine gold wire which is wound in several layers around the exterior
of the tubular member 16, and it will be noted that the tissue-ingrowth
means 18 extends inwardly beyond the tubular member 16 through a
substantial distance toward the tubular means 14. At its outer end region,
beyond which the inner tubular member 16 extends, the tissue-ingrowth
means 18 fixedly carries a plurality of flexible barbs 20. There may be
three such barbs angularly spaced one from the next by 120.degree. about
the axis of the tubular member 16. These barbs project from and may be
integral with a ring 22 which is fixed to the ingrowth means 18 as by
being swaged onto the latter.
The tubular means 14 is of the same general construction as the tubular
means 12. Thus the tubular means 14 also has an inner flexible tubular
member which may be in the form of a tube consisting of coils of stainless
steel or which may be made of silicone rubber material such as a Silastic
type of material. This inner tubular member 24 fixedly carries at its
exterior the tissue ingrowth means 26 which may be identical with the
tissue ingrowth means 18 and which also extends inwardly beyond the inner
end of the tubular member 24 toward the tubular means 12. Also in the same
way as the tubular means 12 the tubular means 14 is provided with barbs 28
which are integral with and project from a ring 30 swaged onto the
tissue-ingrowth means 26 at the outer end region of the latter beyond
which the tubular member 24 extends as illustrated.
An intermediate housing means formed by a housing 32 is fluid-tightly
connected with the pair of tubular means 12 and 14 at their inner end
regions so that the tubular means 12 and 14 are capable of communicating
with each other through the space within the housing 32. The housing 32 is
made of a non-magnetic material such as a suitable plastic and it may be
transparent so that it is possible to look through the housing into the
interior thereof, although transparency of the housing 32 is not
essential. It will be noted that the intermediate portion of the housing
32 is of a substantially spherical configuration and has a diameter
substantially greater than the diameter of either one of the tubular means
12 and 14 so that the cross-sectional area of the housing 32 is
substantially greater than the cross-sectional area of each of the tubular
means 12 and 14. The housing 32 has a tubular extension 34 which receives
the tissue ingrowth means 26 and is fluid-tightly connected with the
tubular means 14 by way of a suitable adhesive 36 such as a silicone
rubber medical adhesive, a Silastic type of adhesive being suitable for
this purpose. It will be noted that the tubular member 24 extends partly
into the extension 34 while the tissue ingrowth means 26 extends beyond
the tubular member 24 through and beyond the extension 34 and through a
substantial distance into the interior of the housing 32. Thus in the
illustrated example the tissue-ingrowth means 26 extends to the region of
the center of the housing 32.
The tubular means 12 is received at its inner end region within a tubular
extension 38 of the housing 32, this extension 38 being longer than the
extension 34, as illustrated. Also in this case the tubular means 12 is
fluid-tightly connected with the housing 32 by way of a suitable adhesive
40 which may be the same as the adhesive 36. In this case the tissue
ingrowth means 18 extends inwardly beyond the inner end of the tubular
member 16 but only up to the region where the extension 38 projects from
the spherical part of the housing 32.
Within the housing 32 is situated a particulate means made up of a
plurality of particles 42. For a purpose referred to below the particles
42 are made of a material which will respond to magnetism. In order to
retain the extremely fine particles 42, which appear to the naked eye as a
powder, reliably within the interior of the housing 32, each tubular means
carries at its inner end region a porous means through which fluid can
flow but having interior spaces which are too small to receive the
particles 42. Thus it will be seen that the tissue ingrowth means 18 is
wound around a cylindrical block 44 which forms the porous means carried
by the tubular means 12, while the tissue-ingrowth means 26 is wound
around a similar block 46 which forms the porous means carried by the
tubular means 14. Each of the blocks 44 and 46 is preferably made of fine
gold filament which is gathered together and compressed so as to be given
the illustrated configuration with the compression used in deforming and
gathering together the filamentary gold wire being sufficiently great to
define between the filamentary material small interstices which provide
for each of the means 44 and 46 the degree of porosity according to which
fluid can flow through each of the means 44 and 46 while the particles 42
cannot be carried through the means 44 and 46. Thus, it will be seen from
the drawing that the tissue ingrowth means 18 and 26 serve to connect the
porous means 44 and 46, respectively, to the tubular means 12 and 14 by
being wound tightly around the porous means 44 and 46. Moreover the inner
end regions of the tissue ingrowth means 18 and 26 are swaged so as to be
pressed inwardly against the blocks 44 and 46 in order to fix the latter
in the positions indicated in the drawing where it will be noted that the
blocks 44 and 46 are spaced slightly beyond the inner ends of the tubular
members 16 and 24. Furthermore it will be noted that the porous means 44
and 46 respectively extend through a slight distance inwardly beyond the
inner ends of the tissue ingrowth means 18 and 26. Thus the pair of tissue
ingrowth means 18 and 26 serve not only the purpose of promoting ingrowth
of tissue into intimate contact with the exterior tubular means 12 and 14
beyond the extensions 34 and 38 of the housing 32, but in addition the
pair of tissue ingrowth means 18 and 26 serve to connect the pair of
porous means 44 and 46 to the pair of tubular means 12 and 14,
respectively.
The above-described means formed by a permanent magnet implant of the
invention is completed by a permanent magnet 48 which surrounds the inner
end region of the tubular means 12. In the illustrated construction the
permanent magnet 48 is fixed directly to the exterior surface of the
housing 32 by a suitable adhesive which may also be a silicone rubber
medical adhesive. It will be noted that the permanent magnet 48 is formed
with an axial bore which receives the tubular extension 38 while this bore
is enlarged at one end so as to conform to the configuration of the
exterior surface of the housing 32 as illustrated.
It is to be noted that the structure of the invention is of a circular
configuration in any plane perpendicular to the common axis of the pair of
tubular means 12 and 14. Moreover, the dimensions of the spherical housing
32 are such that not only is the interior of the housing of a greater
cross sectional area than the interior of either of the tubular means 12
and 14 but in addition the housing extends radially outwardly beyond the
permanent magnet 48.
The permanent magnet 48 may be made of an alloy of platinum and cobalt so
that it forms a strong permanent magnet which at the same time is
compatible with the body of the individual receiving the implant. The fine
particles 42 are preferably made of a magnetically soft material such as
soft-iron of the type used in solenoids or nickel. In either case, which
is to say either when the particles are made of nickel or when they are
made of a soft iron they are gold-plated so as to be compatible with the
body. Such particles are capable of responding to magnetic forces without
being capable of themselves becoming permanent magnets. However, it is
also possible to use for the structure of the invention particles made of
a material which is capable of becoming a permanent magnet such as Alnico,
an alloy of aluminum, nickel, and cobalt, which is known to have strong
magnetic properties.
With the construction described above and shown in the drawing, the
permanent magnet 48 will attract the particles 42 into the
conception-preventing position indicated in the drawing. The quantity of
particles 42 is sufficiently great to enable them to form, under the
influence of the magnet 48, a body of sufficient density to retain sperm
which thus cannot flow through the body formed by the particles 42 into
the downstream tubular means 12. However, the fluid which normally carries
the sperm can flow through the body formed by the magnetically-attracted
particles 42 and through the porous means 44 into the tubular member 16.
The above-described implant can be introduced into a vas deferens according
to known surgical procedures. Thus, surgical access is provided in a known
way to a vas deferens part of which may be excised so that the resulting
tubular free ends of the vas deferens can receive the tubular means 12 and
14 with the vas deferens being drawn at its free ends resulting from the
above excision all the way up to the extremities of the extensions 34 and
38 of the housing 32. The barbs 20 and 28 will dig into the tissue which
defines the lumen of the vas deferens so as to prevent withdrawal thereof
from the implant while maintaining the vas deferens immobilized between
the barbs and the extremities of the housing 32. Thus the parts of the vas
deferens which engage the tissue ingrowth means where the latter projects
beyond the housing 32 will rapidly grow into the tissue ingrowth means
into intimate contact with the exterior of the tubular members 16 and 24
providing an exceedingly secure connection in an extremely effective
manner and in a minimum time. The flexibility of the tubular members 16
and 24 where they project beyond the tissue ingrowth means prevents
kinking of the vas deferens so that a smooth flow through the latter is
assured.
As was pointed out above, the total length of the implant of the invention
from the outer end of the tubular member 16 to the outer end of the
tubular member 24 is on the order of 1 inch. The spherical housing 32 can
have an inside diameter on the order of 0.165 inch while the thickness of
the wall of the housing 32 is on the order of 0.005 inch. As was pointed
out above the housing 32 is made of a non-magnetic material such as a
suitable plastic which may be, for example, polyethylene. In addition, the
housing 32 may be made of gold, or it may be made of a suitable
non-magnetic metal such as, for example, stainless steel. The barbs 20 and
28 may be made of stainless steel. The tubular member 24 may extend
outwardly beyond the tissue ingrowth means 26 through a distance of, for
example, 0.190 inch, while the tissue ingrowth means 26 may extend
outwardly beyond the extension 34 through a distance of, for example,
0.130 inch. The extension 34 itself may have a length on the order of
0.060 inch, and the extension 38 may project through the same distance
outwardly beyond the permanent magnet 48 which may have an outside
diameter on the order of 0.156 inch, and an inside diameter on the order
of 0.050 inch, and a length on the order of 0.125 inch. Thus, the distance
from the outer end of tissue ingrowth means 18 to the outer end of tissue
ingrowth means 26 may be on the order of 0.620 inch, while the distance
between the outer extremities of the extensions 34 and 38 may be on the
order of 0.360 inch and the distance from the inner end of porous barrier
46 to the outer end of tissue ingrowth means 26 may be on the order of
0.282 inch. Each barrier 44 and 46 can project inwardly beyond the tissue
ingrowth means surrounding the same through a distance on the order of
0.010 inch. Each of the porous means 44 and 46 may have an outside
diameter on the order of 0.025 inch and may have a length on the order of
0.135 inch.
Thus, with an implant as described above situated in a vas deferens, the
fluid which carries the sperm can flow into the tubular means 14 and
through the porous barrier 46 into the interior of the housing 32. From
the latter the fluid can flow through the body formed by the magnetically
attracted particles 42 while the sperm will be retained by the latter, and
then the fluid without sperm therein in sufficient numbers to provide
conception can continue to flow through the porous means 44 and the
tubular means 16.
When it is desired to provide for the particles 42 a conception-enabling
position, it is only necessary to situate next to the skin of the
individual who has implants of the above type introduced into his vas
deferentia a suitable permanent magnet, situated in the region of the
scrotum, for example, this latter exterior permanent magnet being stronger
than the permanent magnet 48 to an extent sufficient to attact the
particles 42 away from their conception-preventing position shown in the
drawing to a conception-enabling position where the particles 42 are
situated to one side of the common axis of the tubular means 12 and 14
beyond the path of flow of fluid between the pair of tubular means 12 and
14. Of course the porosity of the barriers 44 and 46 is sufficiently great
to permit sperm to freely flow therethrough, this porosity only being
small enough to prevent the particles 42 from flowing through the barriers
44 and 46. Thus sperm will now be able to flow through the implant of the
invention so that the conception-preventing implant of the invention is
easily and conviently placed in a condition where the capability of
conceiving is again established. A stronger permanent magnet which is
stronger than the magnet 48 can be held by a suitable strap, for example,
at a suitable location for attracting the particles 42 into their
conception-enabling position, in the case where the particles are made of
a material such as soft iron which responds to magnetic forces but which
cannot become permanently magnetized.
However, as was pointed out above, these particles 42 may be made of a
material which can become permanently magnetized. In this case, by
situating a suitable alternating field at the exterior of the individual
provided with the implants of the invention adjacent to these implants, it
is possible to demagnetize the permanent magnet 48 as well as the
particles 42 so that they will simply fall into the interior of the
housing 32 into the space surrounding the tissue-ingrowth means 26 where
it extends into the interior of the housing 32, and the thus-demagnetized
particles will simply remain in this space out of the path of flow between
the pair of tubular means 12 and 14 so that the capability of again
conceiving is readily reestablished with such a construction also.
A further possibility in this latter connection is illustrated in FIG. 2.
Thus it will be seen that in addition to the magnet 48 at one side of the
housing, the housing carries a second magnet 50 at the opposite side
thereof, this magnet 50 being similar to the magnet 48 but being
oppositely oriented as illustrated. Thus, with this construction it is
also possible simply by applying at the exterior of the body of the
individual provided with the implant a magnet stronger than the magnet 48
to attract the particles 42 away from the magnet 48 and into the field of
the magnet 50 which will under these circumstances attract all of the
particles 48 into the space within the housing which surrounds the inner
end region of the tubular means 14. It will be seen that the particles are
shown in this latter position in FIG. 2. Thus with this construction when
it is desired to provide the conception-enabling condition, it is only
necessary with an exterior magnet to displace the particles from the field
of the magnet 48 into the field of the magnet 50 to be retained by the
latter in a position where the particles will not block the flow of sperm.
Thus with this construction it is not necessary to retain at the exterior
of the body an additional magnet stronger than the magnet 48. However, it
is also possible to demagnetize the magnet 48 so that the particles will
then become attracted to the second magnet 50, so that through this
procedure it is not necessary to utilize an exterior magnet. Then when the
particles are to be returned to their conception-preventing condition, the
magnet 50 can be demagnetized and the magnet 48 can again be magnetized so
that it will attract the particles to the conception-preventing location.
Of course, when it is desired to restore the implant to the condition shown
in FIG. 1 where conception will be prevented, then this same magnet
stronger than the magnet 48 or the magnet 50 is again moved in such a way
as to attract the particles 42 away from the magnet 50 and into the field
of the magnet 48 which now holds the particles again in the position shown
in FIG. 1, so that the conception-preventing condition is again restored.
It is thus apparent that with the implant of the invention it is indeed
possible to prevent sperm from being expelled with the ejaculate in
numbers sufficient for providing conception while at the same time there
is no interruption in the flow of the fluid which normally carries the
sperm so that pressures resulting from blockage of this fluid are reliably
avoided and at the same time hormones and enzymes carried by the fluid
continue to be delivered to the body of the individual even though
conception is reliably avoided.
Instead of utilizing a pair of barrier means 44 and 46 as described above,
it is also possible to use labyrinth types of barrier means. For example a
series of coaxial tubes may be arranged one within the other supported in
any suitable way as by radially extending pins positioned between and
connected with the tubes, and the inner end of the outer tube may have the
construction of a channel of U-shaped cross section defining a circular
groove which receives in its interior the inner end of the next tube, the
outer end of which is closed so that the fluid must flow between the pair
of outer tubes and have its direction reversed at the circular channel at
the inner end of the outer tube, the third tube being spaced from and
surrounded by the second tube and extending from this channel at the inner
end of the first tube so that in this way it is possible to provide a
zig-zag path for the fluid. Of course the third tube from the outside
would be received in a circular groove formed by a flange of U-shaped
cross section at the front end of the next inner tube, so that the fluid
can be returned to the desired direction of flow toward the outlet. With
such a labyrinth type of construction it is also possible to retain the
particles while permitting the fluid which normally carries the sperm to
flow through the device. For safety purposes small magnets can be
positioned at the outer ends of the tubular members 16 and 24 so that if
one or more particles should happen to be carried along with the fluid
through the labyrinth passage such particles will be retained by such
small magnets at the ends of the tubular members and thus prevent it from
flowing beyond the device.
In connection with the above description and the claims which follow,
reference has been made to the particles 42. While the term "particles" is
of course intended to cover extremely small grains of solid material which
may have the consistency of a powder, for example, it is also intended for
the term particles to cover extremely small members in the form of fine
hairs or filaments which will also function in the desired manner as the
particles which can be magnetically attracted to form a body in the
density of which will reliably retain sperm while permitting the fluid
which carries the sperm to continue to flow without the sperm being
carried thereby.
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