Note: Descriptions are shown in the official language in which they were submitted.
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HYPOBARICALLY-CONTROLLED, DOUBLE-SOCKET
ARTIFICIAL LllVIB WITH MECHANICAL INTER1LOCK
BACKGROUND OF THE INVENTION
The present invention relates to prosthetic devices and more particularly to a
hypobarically-controlled artificial limb for amputees.
An amputee is a person who has lost part of an extremity or limb such as a leg
or
arm which commonly may be termed as a residual limb. Residual limbs come in
various
sizes and shapes with respect to the stump. That is, most new amputations are
either
slightly bulbous or cylindrical in shape while older amputations that may have
had a lot of
atrophy are generally more conical in shape. Residual limbs may further be
characterized
by their various individual problems or configurations including the volume
and shape'of a
stump and possible scar, skin graft, bony prominence, uneven limb volume,
neuroma,
pain, edema or soft tissue configurations.
Referring to FIGS. l and 2, a below the knee residual limb 10 is shown and
described as a leg 12 having been severed below the knee terminating in a
stump 14. In
this case, the residual limb 10 includes soft tissue as well as the femur 16,
knee joint 18,
and severed tibia 20 and fibula 22. Along these bone structures surrounded by
soft tissue
are nerve bundles and vascular routes which must be protected against external
pressure to
avoid neuromas, numbness and discomfort as well as other kinds of problems. A
below
the knee residual limb 10 has its stump 14 generally characterized as being a
more bony
structure while an above the knee residual limb may be characterized as
including more
soft tissue as well as the vascular routes and nerve bundles.
Referring to FIG. 2, amputees who have lost a part of their arm 26, which
terminates in a stump 28 also may be characterized as having vascular routes,
nerve
bundles as well as soft and bony tissues. The residual limb 10 includes the
humerus bone
30 which extends from below the shoulder to the elbow from which the radius 34
and ulna
36 bones may pivotally extend to the point of severance. Along the humerus
bone 30 are
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the biceps muscle 38 and the triceps muscle 40 which still yet may be
connected to the
radius 34 and the ulna 36, respectively.
In some respects, the residual limb amputee that has a severed arm 26 does not
have the pressure bearing considerations for an artificial limb but rather is
concerned with
having an artificial limb that is articulable to offer functions typical of a
full arm, such as
bending at the elbow and grasping capabilities. An individual who has a
paralyzed limb
would also have similar considerations wherein he or she would desire the
paralyzed limb
to have some degree of mobility and thus functionality.
Historically, artificial limbs typically used by a leg amputee were for the
most part
all made out of wood such as an Upland Willow. The limbs were hand carved with
sockets for receiving the stump 14 of the residual limb i0. Below the socket
would be the
shin portion with the foot below the shin. These wooden artificial limbs were
covered
with rawhide which often were painted. The sockets of most wood limbs were
hollow as
the limbs were typically supported in the artificial limb by the
circumferential tissue
adjacent the stump 14 rather than at the distal end of the stump 14.
Some artificial limbs in Europe were also made from forged pieces of metal
that
were hollow. Fiber artificial limbs were also used which were stretched around
a mold
after which they were permitted to dry and cure. Again, these artificial limbs
were
hollow and pretty much supported the residual limb about the circumferential
tissue
adjacent the stump 14.
All of these various artificial limbs have sockets to put the amputee's stump
14
thereinto. There are generally two categories of sockets. There are hard
sockets wherein
the stump goes right into the socket actually touching the socket wall without
any type of
liner or stump sock. Another category of sockets is a socket that utilizes a
liner or insert.
Both categories of sockets typically were opened ended sockets where they had
a hollow
chamber in the bottom and no portion of the socket touched the distal end of
the stump 14.
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So, the stump was supported about its circumferential sides as it fits against
the inside wall
of the sockets.
These types of sockets caused a lot of shear force on the stump 14 as well as
had
pressure or restriction problems on the nerve bundles and vascular flow of
fluid by way of
the circumferential pressure effect of the socket on the limb. This pressure
effect could
cause a swelling into the ends of the socket where an amputee may develop
severe edema
and draining nodules at the end of their stump 14.
With time, prosthetists learned that by filling in the socket's hollow chamber
and
encouraging a more total contact with the stump and the socket, the swelling
and edema
problems could be eliminated. However, the problematic tissue configurations,
such as
bony prominences, required special consideration such as the addition of soft
or pliable
materials to be put into the socket.
Today, most artificial limbs are constructed from thermoset plastics such as
polyester resins, acrylic resins, polypropylenes and polyethylenes, which are
perhaps
laminated over a nylon stockinette which also may be impregnated by the
various resins.
In the past, most artificial limbs were suspended from the amputee's body by
some
form of pulley, belt or strap suspension often used with various harnesses and
perhaps
leather lacers or lacings. Another method of suspending artificial limbs is
known as the
wedge suspension wherein an actual wedge is built into the socket which is
more closed at
its top opening. The wedge in the socket cups the medial femoral condyle or
knuckle at
the abductor tubical. Yet another form of suspension is referred to as the
shuttle system
or a mechanical hookup or linkup wherein a thin suction liner is donned over
the stump
that has a docking device on the distal end which mechanically links up with
its
cooperative part in the bottom of the socket chamber. Sleeve suspensions were
also used
wherein the amputee may use a latex rubber tube which forms into a rubber-like
sleeve
which would be rolled on over both the top of the artificial limb and onto the
amputee's
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thigh. The sleeve suspensions have been used in combination with other forms
of
suspensions techniques.
Both the use of a positive pressure system and the use of a negative pressure
system (or hypobaric closed chamber) have been utilized in the field of
prosthetics. At
one time, for pressure systems "inflatable inner tubes" were used to fit into
sockets.
Presently, there are pneumatic "bags" which are strategically placed over what
people
consider to be good weight-bearing areas to increase pressure to help
accommodate for
volume changes within the socket.
The problem with this is that it is a very specific pressure and creates
atrophy and
loss of tissue dramatically over these high pressure areas. None of these
systems employs
positive pressure distributed over the total contact area between the residual
limb and the
artificial limb socket to accommodate volume changes within the socket.
The negative pressure aspects have been utilized for a closed chamber in that
a
socket is donned by pulling in with a sock, pulling the sock out of the socket
and then
closing the opening with a valve. This creates a seal at the bottom and the
stump is held
into the socket by the hypobaric seal. However, there are no systems that
employ a
negative pressure produced by a vacuum pump to lock the residual limb to the
artificial
limb.
The older systems were initially started in Germany. They were an open-ended
socket, meaning there was an air chamber in the bottom of the socket. This did
not work
particularly well because it would cause swelling of the residual limb into
the chamber
created by the negative draw of suspending the weight of the leg and being
under a
confined area. This would lead to significant edema which would be severe
enough to
cause stump breakdown and drainage.
It was later discovered in America that total contact was essential between
the
residual limb and the socket and once you had total contact the weight was
distributed
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evenly or the suspension was distributed over the whole surface of the limb
rather than
j ust over the open chamber portion of the socket.
The human body as a whole is under approximately one atmosphere of pressure at
sea level. It keeps and maintains a normal fluid system throughout the body.
When an
amputee dons a prosthesis and begins taking the pressures of transmitting the
weight of the
body through the surface area of the residual limb to the bone, there is
increased pressure
on the residual limb equal to one atmosphere plus whatever additional
pressures are
created by weight bearing. This increased pressure causes the eventual loss of
fluids
within the residual limb to the larger portion of the body which is under less
pressure.
This loss of fluids causes the volume of the residual limb to decrease during
the day. It
varies from amputee to amputee, but it is a constant among all amputees and
the more
"fleshy" and the softer the residual limb, the more volume fluctuation there
will be. The
greater the weight and the smaller the surface area, the greater the pressures
will be and
the more "swings" there will be in fluids. In the past, the amputee had to
compensate for
this volume decrease by removing the artificial limb and donning additional
stump socks to
make up for the decreased residual limb volume.
While some of these devices addressed some of the problems associated with
prosthetics, none of the artificial limbs, liners and sockets, individually or
in combination,
offered a prosthesis that presented a total contact relationship with the
residual limb;
absorbed and dissipated shear, shock and mechanical forces transmitted to the
limb tissues
by the artificial limb; controlled residual limb volume; used negative
pressure as a locking
device to hold the residual limb into the socket; and used positive pressure
not for specific
weight bearing, but to totally adjust and adapt the internal socket
environment.
There is a need for an improved hypobarically-controlled artificial limb that
will
offer total contact relationship with the residual limb; absorb and dissipate
shock,
mechanical and shear forces typically associated with ambulation, twisting and
turning and
weight bearing with an artificial limb; control residual limb volume by way of
even weight
distribution; use negative pressure as a locking device to hold the residual
limb into the
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socket; use positive pressure to totally adjust and adapt the internal socket
environment to
changes in residual limb volume; and control stump volume changes by
cooperation
between a negative pressure system and a positive pressure system. Ideally,
the vacuum
system and positive pressure system should be automatically regulated.
There is also a need for an improved hypobarically-controlled artificial limb
with a
positive mechanical interlock between an inner socket, which receives the
residual limb,
and an outer socket which attaches to the shin and foot of the artificial
limb. Both the
inner socket and the outer socket should have a rigid lower portion for weight-
bearing and
a substantially flexible upper portion to allow movement of the residual limb.
In the past, artificial limbs had to be custom-built for the amputee. The
custom
building process generally consisted of: placing a singly ply thin cotton
casting sock over
the residual limb; making a first negative mold of the residual limb by
forming an
orthopedic plaster wrap about the residual limb and casting sock; making a
first positive
model of the residual limb by filling the negative mold with plaster; forming
a
thermoplastic foam about the positive model to create a space for a liner;
adding additional
thermoplastic foam to form a distal end cap as well as other areas which may
require
additional thicknesses due to tissue configurations; forming a second enlarged
negative
plaster mold about the foam; removing the foam; pouring a liquid and moldable
liner into
the space between the positive model and the second negative mold; allowing
the liner to
harden; removing the liner from the second negative mold; having the amputee
don the
liner over the residual limb; placing another single ply thin casting sock
over the liner;
making a third plaster wrap or negative mold of the artificial limb socket
about the
residual limb and the liner; removing the liner from the third plaster wrap;
making a
plaster cast or positive model of the socket from dental plaster; milling or
shaving the
positive model to create a reduced positive model to create weight bearing
areas and
compression of the liner against the residual limb and the socket; and making
the socket
from the reduced positive model.
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This custom-building process is expensive, time-consuming, and requires the
constant attention of a skilled prosthetist.
There is a need for a generic artificial limb socket which can be fitted to
the
contours of the residual limb without the need for a lengthy, expensive custom-
molding
process. The socket should contain a semi-compressible molding material which
can be
molded to the contours of the residual limb under vacuum and/or positive air
pressure.
SZTMMARY OF THE INVENTION
A hypobarically-controlled artificial limb for amputees includes an outer
socket, a
flexible, compressible inner socket interlockable within the outer socket with
a cavity for
receiving the residual limb, a space between the inner socket and the outer
socket, a
vacuum source connected to the cavity, a positive pressure source connected to
the space,
a regulator for controlling the vacuum source and positive pressure source,
and a seal for
making an airtight seal between the residual limb and the socket. Another
embodiment
includes a semi-compressible molding material in the space to mold to the
contours of the
residual limb under the influence of vacuum and/or positive pressure. Another
embodiment includes a positive mechanical interlock between the inner socket
and the
outer socket.
A principle object and advantage of the present invention is that it uses
vacuum
within the artificial limb socket to suspend the artificial limb from the
residual limb.
Another object and advantage of the present invention is that it uses vacuum
within
the artificial limb socket to compensate for socket fit and volumetric changes
within the
socket.
Another object and advantage of the present invention is that it uses vacuum
within
the socket to lock the residual limb into the socket while preventing negative
draw within
the socket from causing swelling of the residual limb into the socket.
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Another object and advantage of the present invention is that it uses vacuum
within
the socket to oppose the loss of fluids from the residual limb caused by
weight-bearing
pressures.
Another object and advantage of the present invention is that it uses positive
pressure within the socket to automatically reduce socket volume to compensate
for fluid
loss in the residual limb.
Another object and advantage of the present invention is that it uses both
vacuum
and positive pressure working together to lock the residual limb into the
socket and reduce
socket volume to compensate for fluid loss in the residual limb.
Another object and advantage of the present invention is that both the vacuum
and
the positive pressure may be created by a miniaturized pump with a motor
drive.
Another object and advantage of the present invention is that it includes a
digital
computer system to control the miniaturized pump to regulate both negative
pressure and
positive pressure.
Another object and advantage of the present invention is that it includes a
semi-
compressible molding material between the outer socket and the inner socket
which may
be molded to the contours of the artificial limb under the influence or vacuum
and/or
positive pressure, thereby avoiding the need for a custom-building process.
Another object and advantage of the present invention is that the inner socket
and
outer socket are interlockable with each other to prevent relative movement.
The
interlocking may be achieved by any of a variety of mechanisms, such as pins
or detents.
The inner socket is removable from the outer socket.
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. Another object and advantage of the present invention is that the vacuum
pump and
the vacuum regulator may be enclosed in the space between the outer socket and
the inner
. socket, thereby preventing damage to these components. The vacuum regulator
may be
controlled by an externally-accessible vacuum control.
Another object and advantage of the present invention is that both the inner
socket
and the outer socket nay be constructed of a lower, rigid portion and an upper
substantially flexible portion. The lower rigid portion provides the necessary
rigidity to
support the person's weight, while the upper flexible portion accommodates
movement of
the residual limb.
Another object and advantage of the present invention is that includes an
outer
sheath between the inner socket and the suspension sleeve, to prevent abrasion
of the
suspension sleeve by the inner socket.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the tissue and skeletal structure of an
amputee's residual limb;
FIG. 2 is a side elevational view of a residual limb in the form of an
amputated
arm showing the skeletal and muscular structure of the residual limb;
FIG. 3 is an exploded elevational view of the residual limb donning the
polyurethane sleeve, stretchable nylon sleeve, liner, nylon sheath and socket
of an
artificial limb;
FIG. 4 is a cross-section of the artificial limb in FIG. 3, which is a first
embodiment of the artificial limb.
FIG. 5 is a cross-section of the artificial limb similar to FIG. 4, showing a
second
embodiment of the artificial limb.
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FIG. 6 is the same as FIG. 5, but showing compression of the inner socket
under
the influence of positive air pressure.
FIG. 7 is a cross-section of the artificial limb showing a third embodiment of
the
artificial limb.
FIG. 8 is a cross-section of the artificial limb showing a fourth embodiment
of the
artificial limb.
FIG. 9 is an elevational view of the polyurethane sleeve and second
stretchable
nylon sleeve rolled over the socket and residual limb with clothing shown in
broken
outline.
FIG. 10 is a cross-section of the artificial limb showing a fifth embodiment
of the
artificial limb.
FIG. 11 is a cross-section of the artificial limb showing a sixth embodiment
of the
artificial limb.
FIG. 12 is a detailed view of the vacuum mechanism in FIG. 11.
FIG. 13 is a cross-section of the artificial limb showing a seventh embodiment
of
the artificial limb.
FIG. 14 is a detailed view of the vacuum mechanism and suspension sleeve of
FIG. 13.
FIG. 15 is a perspective view of the suspension sleeve of the seventh
embodiment
with detailed structure blown up.
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DESCRIPTION OF THE PREFERRED EMBODI1VIENT
FIG. 3 shows the hypobarically-controlled artificial limb 50 of the present
invention. The hypobarically-controlled artificial limb 50 includes an outer
socket 52,
shin 54, and foot 56. The outer socket 52 has a volume and shape to receive a
substantial
portion of the residual limb 14 with a space 58 therebetween.
A first embodiment of the hypobarically-controlled artificial limb 50 is shown
in
FIG. 4. The hypobarically-controlled artificial limb 50 further includes a
flexible inner
socket 60 with a cavity 62 with a volume and shape for receiving a substantial
portion of
the residual limb 14 and fitting in the space 58 between the outer socket 52
and the
residual limb 14. The inner socket 60 has an inner surface 64 opposing the
residual limb
14 and an outer surface 66 opposing the outer socket 52.
A vacuum source 70 may conveniently be attached to the shin 54. The vacuum
source 70 may preferably be a motor-driven pump 72. The vacuum source 70 is
connected to a power source 83, which may be a battery.
A vacuum valve 74 is suitably connected to the vacuum source 70. The vacuum
valve 74 may preferably be disposed on the outer socket 52. A vacuum tube 76
connects
the vacuum valve 74 to the cavity 62. It will be seen that the vacuum source
will cause
the residual limb 14 to be drawn into firm contact with the inner surface 64
of the inner
socket 60.
The hypobarically-controlled artificial limb 50 also includes a regulator
means 80
for controlling the vacuum source 70. Preferably, the regulator means 80 may
be a digital
computer 82. Alternately, the regulator means may be a vacuum regulator. The
regulator
means 80 is connected to a power source 83, which may be a battery.
A seal means 84 makes an airtight seal between the residual limb 14 and the
outer
socket 52. Preferably, the seal means 84 is a nonfoamed, nonporous
polyurethane
suspension sleeve 86 which rolls over and covers the inner socket 60 and a
portion of the
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residual limb 14. Alternatively, the seal means 84 may be any type of seal
which is
airtight.
The hypobarically-controlled artificial limb 50 may also include a thin sheath
90
between the residual limb 14 and the inner surface 64 of the inner socket 60.
As vacuum
is applied to the cavity 62, the sheath 90 will allow the vacuum to be evenly
applied
throughout the cavity 62. Without the sheath 90, the residual limb 14 might
"tack up"
against the inner surface 64 and form a seal which might prevent even
application of the
vacuum to the cavity 62. The sheath 90 may also be used to assist the amputee
into a
smooth and easy fitting into the inner socket 60. The sheath 90 is preferably
made of thin
knitted nylon.
The hypobarically-controlled artificial limb 50 may also include a nonfoamed,
nonporous polyurethane liner 92 receiving the residual limb 14 and disposed
between the
sheath 90 and the residual limb 14. The liner 92 provides a total-contact
hypobaric
suction, equal weight distribution socket liner. The liner 92 readily tacks up
to the skin of
the residual limb 14 and provides total contact with the limb 14. The liner 92
absorbs and
dissipates shock, mechanical and shear forces typically associated with
ambulation.
The hypobarically-controlled artificial limb 50 may also include a stretchable
nylon
second sleeve 94 for rolling over and covering the suspension sleeve 86 to
prevent
clothing from sticking to and catching the suspension sleeve 86.
Referring to FIG 3, the polyurethane tubular sleeve 86 may be appreciated
alone
and in combination with the urethane liner 92 together with the optional nylon
sheath 90
and second stretchable nylon sleeve 94.
More specifically, the amputee takes the stretchable nylon second sleeve 94,
suitably made of a spandex-like material and rolls it up over the stump 14 to
the upper
portions of the residual limb suitably as the thigh of a leg I2. Next, the
polyurethane
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. sleeve 86 is also rolled upwardly over the residual limb 10. Thereafter, the
liner 92 is
optionally donned.
Next, the amputee may optionally utilize the nylon sheath 90 which is suitably
of a
non-stretching, thin, friction reducing nylon. As stated, this sheath 90
optionally may be
used to assist the amputee into a smooth and easy fitting into the inner
socket 60.
Alternatively, the sheath 90 may be avoided and the liner 92 simply inserted
into the inner
socket 60 of the artificial limb 50.
Next, the amputee simply grasps the rolled over portion of the polyurethane
sleeve
86 and rolls it over a substantial portion of the outer socket 52. The sleeve
86 makes an
airtight seal between the residual limb 14 and the outer socket 52.
As can be appreciated, the polyurethane sleeve 86 is tacky. Consequently, the
stretchable nylon second sleeve 94 may be utilized and rolled over the
polyurethane sleeve
86.
The amputee then sets the regulator means 80 to cause the vacuum source 70 to
apply vacuum through the vacuum valve 74 and vacuum tube 76 to the cavity 62.
Enough
vacuum is applied to cause the residual limb (with optional coverings) to be
drawn firmly
against the inner surface 64 of the inner socket 60, which is flexible. The
vacuum source
70 may preferably maintain a vacuum in the range of 0 to 25 inches of mercury.
It will be seen that the vacuum within the inner socket 60 will cause the
hypobarically-controlled artificial limb 50 to be suspended from the residual
limb 14. The
vacuum will lock the residual limb 14 into the inner socket 60 without causing
swelling of
the residual limb into the socket, because of the total contact of the
residual limb 14 with
the inner socket 60. That is, there is no open chamber between the residual
limb 14 and
the inner socket 60 which would draw on the residual limb.
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As the volume of the residual limb 14 decreases during the day due to weight-
bearing pressures, the regulator means 70 may appropriately adjust the vacuum
source 70
to draw the residual limb 14 more firmly against the inner socket 60 and thus
compensate
for the loss of residual limb volume. The vacuum may also partially oppose the
Ioss of
fluids from the residual limb caused by weight-bearing pressures.
A second embodiment of the hypobarically-controlled artificial limb 50 is
shown in
FIGS. 5 and 6. The second embodiment of the hypobarically-controlled
artificial limb 50
is as described above, with the exception that the inner socket 60A is
compressible as well
as being flexible. Instead of a vacuum source, the second embodiment has a
positive air
pressure source 100, which may preferably be a motor-driven pump 102. The
regulator
means 80, which may be a digital computer 82, controls the positive air
pressure source
100. The regulator means and positive air pressure source 100 are connected to
a power
source 83, which may be a battery. A positive pressure valve 104 connects the
space 58
to the positive air pressure source 100, for compressing the inner socket 60A
as the
volume of the residual limb decreases.
It will be seen that as the volume of the residual limb 14 decreases during
the day
due to weight-bearing pressures, the regulator means 80 may control the
positive air
pressure source 100 to cause air pressure to compress the inner socket 60A to
compensate
for the decreased volume of the residual limb, as shown in FIG. 6.
A third embodiment of the hypobarically-controlled artificial limb 50 is shown
in
FIG. 7. The third embodiment is a combination of the first and second
embodiments
described above.
The motor-driven pump 72 may act as both the vacuum source 70 and the positive
air pressure source 100. The regulator means 80, vacuum source 70 and positive
air
pressure source 100 are connected to a power source 83, which may be a
battery.
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The vacuum source 70, under control of the regulator means 80, will compensate
for reduced residual limb volume up to a certain point. From that point on,
the regulator
means 80 will cause the positive air pressure source 100 to further compensate
for reduced
residual limb volume as described above. The third embodiment thus uses both
vacuum
and positive air pressure working together to lock the residual limb 14 into
the inner
socket 60 and reduce socket volume to compensate for fluid loss in the
residual limb 14.
The exact point at which the changeover is made between vacuum compensation
and
positive air pressure compensation is controlled by the regulator means 80,
which as
described may be a digital computer appropriately programmed for the socket
environment.
A fourth embodiment of the hypobarically-controlled artificial limb 50 is
shown .fin
FIG. 8. The fourth embodiment is like the first embodiment, but includes two
vacuum
valves: a first vacuum valve 106 and a second vacuum valve 110, both connected
to the
vacuum source 70. The first vacuum valve 106 connects the vacuum source 70 to
the
space 58. The space 58 contains a semi-compressible material 108, such as
polystyrene
beads, as disclosed in U.S. Patent No. 4,828,325.
To don the artificial limb 50, the amputee proceeds as described above. After
inserting the residual limb 14 (with optional coverings) into the inner socket
60B, which is
both compressible and expandable, and rolling the suspension sleeve 86 over
the outer
socket 52, the amputee activates the regulator means 80, causing the vacuum
source 70 to
apply a vacuum to the space 58. This causes the material 108 to lock
mechanically
together into a rigid mass, conforming to the shape of the residual limb 14.
The inner
socket 60B may expand slightly under the weight of the residual limb 14 and
under the
influence of vacuum.
It will be seen that the semi-compressible molding material 108 can be molded
to
the contours of the residual limb 14 without using a custom-building process
to produce a
custom socket. The outer socket 52 may appropriately occur in standard sizes,
such as
small, medium, and large. The inner socket 60B may also occur in standard
sizes such as
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small, medium, and large. Adaptation of the inner socket 60B to the contours
of the
residual limb 14 occurs through solidifying the material 108 under the
influence of
vacuum.
The second vacuum valve 110 connects the vacuum source 70 to the cavity 62 as
previously described, for locking the residual limb 14 into the inner socket
60B.
The fourth embodiment may also include a positive air pressure source 100 as
previously described, to adjust the size of the inner socket 60B to compensate
for
decreased residual limb volume.
1fie fourth embodiment may also include a thin sheath 90, liner 92, and second
sleeve 94, as previously described.
The positive air pressure source 100 may also be used for shock absorption and
a
dynamic response in the ankle and foot sections of the artificial limb 50, by
means of a
connection 120.
A fifth embodiment of the hypobarically controlled artificial limb 50 is shown
in
FIG. 10. This embodiment is the same as the first embodiment shown in FIG. 4,
with
some changes. First, vacuum source ?1 may be a hand-operated vacuum pump 71
which
may remove air from the cavity 62 down to 25 inches of mercury but more
commonly
down by three to six inches of mercury. A suitable hand-operated vacuum pump
is
marketed under the trademark MITY VAC II~ by Neward Enterprises, Inc. of
Cucamonga, California.
The fifth embodiment also includes the seal means 84 which preferably consists
of
a non-foamed, nonporous polyurethane suspension sleeve 86 for rolling over and
covering
a portion of the residual limb 14. A portion of the seal means 86 is adapted
to be
disposed between the outer socket 52 and the inner socket 60. The sleeve may
be made of
any of a variety of air-impervious elastomers.
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The fifth embodiment, shown in FIG. 10, also includes a mechanical interlock
67,
59 for interlocking the inner socket 62 with the outer socket 52. Preferably,
the
mechanical interlock consists of a first detent 67 in the inner socket 62 and
a second detent
59 in the outer socket 52. The first detent 67 engages the second detent 59 to
lock the
inner socket 60 into the outer socket 52.
A sixth embodiment of the hypobarically-controlled artificial limb of the
present
invention is shown in FIGS. 1 i and i2. The sixth embodiment is like the first
embodiment shown in FIG. 4, with some changes.
First, the inner socket is specifically intended to be removable from the
outer
socket. To provide a positive mechanical connection between the inner socket
and outer
socket and yet allow the inner socket to be easily removed, the sixth
embodiment includes
a mechanical interlock 103 engaging the inner socket 60 and the outer socket
52.
Preferably, the mechanical interlock may be an extension 104 which is attached
to the
inner socket 60 and a docking device 106 attached to the outer socket 52 and
receiving the
extension 104, and a locking mechanism 105 engaging the extension 104 and the
docking
device 106.
The extension may be any sort of protrusion from the inner socket, such as a
bulge
or tab. Preferably, the extension 104 comprises a shuttle pin 108.
The locking mechanism may be any sort of member which engages both the
extension 104 and the docking device 106, such as a screw, wire, or pin.
Preferably, the
locking mechanism 105 comprises a second pin 110 which extends outside the
outer socket
52 as to be accessible.
Second, the sixth embodiment includes two thin sheaths, rather than one. A
first
inner sheath 90 may preferably be disposed between the residual limb 14 and
the inner
surface 64 of the inner socket 60. As vacuum is applied to the cavity 62, the
inner
sheath 90 will allow the vacuum to be evenly applied throughout the cavity 62.
Without
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the inner sheath 90, the residual Iimb 14 might "tack up" against the inner
surface 64 and
form a seal which might prevent even application of the vacuum to the cavity
62. The
inner sheath 90 may also be used to assist the amputee into a smooth and easy
fitting into
the inner socket 60.
An outer sheath 93 is preferably disposed between the suspension sleeve 86 and
the
inner socket 60, thereby preventing the suspension sleeve from tacking to the
inner socket
60. Such tacking would cause friction between the inner socket b0 and the
sleeve 86
which would cause the sleeve to wear out. Such tacking might also cause
restrictions in
the movement of the residual limb. The outer sheath 93 also protects the
suspension
sleeve 86 from being damaged by friction with the inner socket 60.
The sixth embodiment also preferably includes an adhesive pressure tape 95
adapted to cover the outer sheath 93, suspension sleeve 86, and the second
sleeve 94 and
sealing the outer sheath 93, suspension sleeve 86, and the second sleeve 94 to
the inner
socket 60. The tape 95 locks all of these layers to the inner socket so that
they do not
come loose during movement.
In the sixth embodiment, the suspension sleeve 86 goes between the inner
socket
60 and the outer socket 52, so that the sleeve 86 is protected from damage.
In the sixth embodiment, the inner socket 60 has a rigid lower portion 98 and
a
substantially flexible upper portion 96. The rigid Iower portion assists in
weight-bearing
while the substantially flexible upper portion allows for movement of the
residual limb 14.
As the knee is bent from fully straight to fully flexed, the width of the knee
changes rather
significantly and in a hard, non-flexible socket brim, there can be excessive
pressure on
the residual limb 14. The substantially flexible upper portion 96 makes the
artificial limb
50 more comfortable and more adaptive to these changes. For the same reason,
the outer
socket 52 has a rigid lower portion 102 and a substantially flexible upper
portion 100.
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Preferably, the top edge of the inner socket 60 is below the top edge of the
outer
socket 52 so that the sleeve 86 is protected from impact. Preferably, the top
edge of the
inner socket 60 may be 3/16 inch below the top edge of the outer socket 52.
The sixth embodiment includes extensive modifications to the vacuum system.
First, a vacuum fitting 78 has been added to the inner socket 60 to attach the
vacuum tube 76. The vacuum fitting 78 allows the attachment of a vacuum sensor
79
adapted to sense the amount of vacuum in the cavity 62 and a sensor lead 81 is
attached to
the sensor 79 connecting the sensor 79 to the regulator means 80, thus
conveying the
sensed vacuum to the regulator means 80.
A vacuum valve 74 is placed between the cavity 62 and the vacuum source 70 to
maintain vacuum in the cavity 62. Typically, the vacuum valve 74 is a one-way
valve or
non-return valve.
In the sixth embodiment, the vacuum source 70, vacuum tube 76, vacuum valve
74, regulator means 80, and power source 83 are all attached to the outer
socket 52 in the
space 58 between the outer socket 52 and inner socket 60. In this way, these
delicate
components are protected against being damaged by impact. Because of the
placement of
the regulator means 80 within the outer socket 52, a vacuum control 77 is
provided
extending outside the outer socket 52 to allow manual control of the regulator
means 80.
The amputee dons the sixth embodiment in a manner similar to that earlier
described, with some modifications. First, the outer sheath 93 is put on the
residual limb
14 after rolling the suspension sleeve 86 upward over the residual limb and
before donning
the liner 92. After donning the inner sheath 90 over the liner 92, the amputee
inserts the
residual limb 14 into the inner socket 60. Next, the outer sheath 93,
suspension sleeve
86, and second sleeve 94 are rolled down over the inner socket 60, and the
adhesive
pressure tape 95 is applied. Next, the wearer sets the regulator means 80 to
an
appropriate vacuum level by means of the vacuum control 77, and connects the
vacuum
CA 02290414 2003-O1-30
_'7()_
tube 76 to the vacuum fitting 78. The inner socket 60 is then placed within
the
outer socket 52 so that the shuttle pin 108 engages the docking device 106 and
the locking pin 110 is set to engage the shuttle pin 108 and the docking
device
L06, providing a positive mechanical interlock.
A seventh embodiment of the hypobarically-controlled artificial limb of
the present invention is shown in FIG. 13. The seventh embodiment is similar
to
the sixth embodiment, with some changes.
First, the mechanical interlock l03 does not engage the inner socket 60.
Instead, the mechanical interlock engages the outer socket 52 and the
suspension
sleeve 86. To accomplish this, the suspension sleeve 86 covers the entire
inner
socket 60, and the suspension sleeve 86 has the extension lt)4 or shuttle pin
108
embedded in the suspension sleeve at the distal end of the suspension sleeve,
as
shown in FIG. 14. Preferably, the extension 104 has a portion 104A embedded in
the suspension sleeve. This portion 104A may be a disk or umbrella 104A. The
extension 104 then engages the docking device 106 as previously described.
Second, the suspension sleeve 86 is modified to support the additional
weight imposed on the suspension sleeve 86 due to the outer socket 52 and
artificial limb. In particular, the suspension sleeve 86 is fabricated from a
material which allows circumferential expansion but resists longitudinal
stretching under the weight of the artificial limb. Such a material is
described in
United States Patent No. 5,571,208. FIG. 15 is a modified drawing from the
5,_571,208 patent showing details of construction of the suspension sleeve.
The
sleeve 86 preferably contains fabric threads 250 which may be oriented
circumferentially around the sleeve. The threads 250 preferably are comprised
of
double-knit polyurethane. The threads may also include nylon. The threads 250
permit the sleeve 86 to expand circumferentially so that the sleeve may be
slipped onto the residual limb 14 and so that the lower portion 240 may be
slipped over the inner socket 52.
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The threads 250 are preferably connected together with cross-links 252, which
also
may be preferably comprised of polyurethane. The cross-links 252 and threads
250 form
a matrix 254 which allows circumferential expansion but resists longitudinal
stretching
under the weight of the artificial limb. By example, the sleeve 86 may have a
4-to-1 ratio
of circumferential stretch relative to longitudinal stretch.
The sleeve 86 may have a portion above the inner socket 52 which is
manufactured
of material which allows both vertical and horizontal stretching, to increase
flexibility.
The present invention may be embodied in other specific forms without
departing
from the spirit or essential attributes thereof, and it is therefore desired
that the present
embodiment be considered in all respects as illustrative and not restrictive,
reference being
made to the appended claims rather than to the foregoing description to
indicate the scope
of the invention.
