U.S. patent application number 10/615203 was filed with the patent office on 2004-05-20 for socket liner for artificial limb with permanent attachment to socket.
Invention is credited to Caspers, Carl A..
Application Number | 20040098136 10/615203 |
Document ID | / |
Family ID | 32303454 |
Filed Date | 2004-05-20 |
United States Patent
Application |
20040098136 |
Kind Code |
A1 |
Caspers, Carl A. |
May 20, 2004 |
Socket liner for artificial limb with permanent attachment to
socket
Abstract
A hypobarically-controlled artificial limb for amputees includes
a single socket with a volume and shape to receive a substantial
portion of the residual limb. A sealed cavity is formed between the
socket and the residual limb. The wearer may use a liner over the
residual limb for comfort. A vacuum source is connected to a vacuum
valve connected to the cavity to suspend the artificial limb from
the residual limb and to control and minimize volumetric and fluid
changes within the residual limb. A liner for a
hypobarically-controlled socket for an artificial limb, with an
adhering interface attaching the liner to the inner wall of the
socket and forming a seal between the liner and the socket. The
liner may be permanently attached to the socket.
Inventors: |
Caspers, Carl A.; (Avon,
MN) |
Correspondence
Address: |
Lynn C. Cameron
Faegre & Benson, LLP
2200 Wells Fargo Center
90 South Seventh Street
Minneapolis
MN
55401-3901
US
|
Family ID: |
32303454 |
Appl. No.: |
10/615203 |
Filed: |
July 7, 2003 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10615203 |
Jul 7, 2003 |
|
|
|
09670853 |
Sep 27, 2000 |
|
|
|
09670853 |
Sep 27, 2000 |
|
|
|
09492406 |
Jan 27, 2000 |
|
|
|
6508842 |
|
|
|
|
09492406 |
Jan 27, 2000 |
|
|
|
09325297 |
Jun 3, 1999 |
|
|
|
Current U.S.
Class: |
623/34 ;
623/36 |
Current CPC
Class: |
A61F 2002/704 20130101;
A61F 2002/5053 20130101; A61F 2/80 20130101; A61F 2002/6614
20130101; A61F 2/601 20130101; A61F 2210/0057 20130101; A61F 2/74
20210801; A61F 2002/5003 20130101; A61F 2210/009 20130101; A61F
2002/5052 20130101; A61F 2002/7655 20130101; A61F 2002/7806
20130101; A61F 2002/7881 20130101; A61F 2002/7818 20130101; A61F
2002/5015 20130101; A61F 2/7843 20130101; A61F 2/5046 20130101;
A61F 2002/802 20130101; A61F 2002/805 20130101; A61F 2/7812
20130101 |
Class at
Publication: |
623/034 ;
623/036 |
International
Class: |
A61F 002/80 |
Claims
What is claimed:
1. A liner for a hypobarically-controlled socket for an artificial
limb, the socket having a volume and shape to receive a substantial
portion of an amputee's residual limb with a cavity therebetween,
an inner wall, and a partial vacuum in the cavity tending to draw
the residual limb into firm contact with the socket, the liner
further comprising an adhering interface adapted to sealingly
engage the inner wall of the socket, thereby making a seal between
the residual limb and the socket to minimize air leakage into the
cavity, wherein the adhering interface permanently attaches the
liner to the inner wall of the socket.
2. The liner of claim 1, wherein the adhering interface comprises a
laminating adhesive.
3. The liner of claim 1, wherein the adhering interface comprises
contact cement.
4. The liner of claim 1, wherein the adhering interface comprises a
paint-on glue.
5. The liner of claim 1, further comprising non-foamed, non-porous
polyurethane.
Description
[0001] This is a divisional of U.S. patent application Ser. No.
09/670,853, filed Sep. 27, 2000, which is a continuation-in-part of
U.S. patent application Ser. No. 09/492,406, filed Jan. 27, 2000,
which is a continuation-in-part of U.S. patent application Ser. No.
09/325,297, filed Jun. 3, 1999.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to prosthetic devices and more
particularly to a hypobarically-controlled artificial limb for
amputees.
[0003] An amputee is a person who has lost part of an extremity or
limb such as a leg or arm that 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.
[0004] Referring to FIGS. I 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
that 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.
[0005] 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 that
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 the biceps muscle 38 and
the triceps muscle 40 which still yet may be connected to the
radius 34 and the ulna, 36, respectively.
[0006] 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
having some degree of mobility and thus functionality.
[0007] 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 10. 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.
[0008] 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.
[0009] 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. So, the stump was
supported about its circumferential sides as it fits against the
inside wall of the sockets.
[0010] 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.
[0011] 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.
[0012] 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 that also may be impregnated by the various resins.
[0013] 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 that 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 thigh. The
sleeve suspensions have been used in combination with other forms
of suspensions techniques.
[0014] 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.
[0015] 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.
[0016] 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.
[0017] 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 significance
edema that would be severe enough to cause stump breakdown and
drainage.
[0018] 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 evenly or the suspension
was distributed over the whole surface of the limb rather than just
over the open chamber portion of the socket.
[0019] 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
that 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 amputee 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.
[0020] While some of these devices addressed some of the problems
associated with prosthetics, none of the artificial limbs, liners
and socket, 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; and used negative pressure as a locking
device to hold the residual limb into the socket.
[0021] 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 socket; and to
totally adjust and adapt the internal socket environment to changes
in residual limb volume; and control stump volume changes by a
negative pressure system which is also capable of providing
positive pressure. Ideally, the vacuum system should be
automatically regulated.
[0022] 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 that 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.
[0023] 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 for 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.
[0024] This custom-building process is expensive, time-consuming,
and requires the constant attention of a skilled prosthetist.
[0025] There is a need for a generic artificial limb socket that
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.
SUMMARY OF THE INVENTION
[0026] A hypobarically-controlled artificial limb for amputees
includes a single socket with a volume and shape to receive a
substantial portion of the residual limb. A seal between the socket
and the residual limb. A sealed cavity is formed between the socket
and the residual limb. Optionally, the wearer may use a liner over
the residual limb for comfort. A vacuum source is connected to a
vacuum valve connected to the cavity to suspend the artificial limb
from the residual limb and to control and minimize volumetric and
fluid changes within the residual limb.
[0027] A liner for a hypobarically-controlled socket for an
artificial limb, the socket having a volume and shape to receive a
substantial portion of an amputee's residual limb with a cavity
therebetween and a partial vacuum in the cavity tending to draw the
residual limb into firm contact with the socket and the artificial
limb having a suspension sleeve for rolling over and covering the
socket and a portion of the residual limb, the liner
comprising:
[0028] a) an inner layer adapted to contact the residual limb;
[0029] b) an outer fabric layer engaging said inner layer; and
[0030] c) an annular seal extending outwardly from said outer
fabric layer and adapted to sealingly engage the suspension sleeve,
thereby making a seal between the residual limb and the socket to
minimize air leakage into the cavity.
[0031] 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.
[0032] Another object and advantage of the present invention is
that it uses vacuum within the artificial limb socket to assist in
socket fit and minimizes volumetric limb changes within the
socket.
[0033] 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.
[0034] 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.
[0035] Another object and advantage of the present invention is
that it uses vacuum pressure to lock the residual limb into the
socket and reduce socket volume to compensate for fluid loss in the
residual limb.
[0036] Another object and advantage of the present invention is
that both vacuum and positive pressure may be created by a
miniaturized pump with a mechanical or motor drive.
[0037] 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, when used.
[0038] Another object and advantage of the present invention is
that is includes a semicompressible molding material between the
outer socket and the inner socket which may be molded to the
contours of the artificial limb under the influence of vacuum
pressure, thereby avoiding the need for a custom-building
process.
[0039] 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 a pins or detents.
The inner socket is removable from the outer socket.
[0040] Another object and advantage of the present invention is
that 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.
[0041] Another object and advantage of the present invention is
that both the inner socket and the outer socket may 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.
[0042] Another object and advantage of the present invention is
that it includes an outer sheath between the inner socket and the
suspension sleeve, to prevent abrasion of the suspension sleeve by
the inner socket.
[0043] Another principal object and advantage of the present
invention is that it may comprise only a single socket, rather than
two sockets, simplifying construction and reducing cost and
complexity.
[0044] Another principal object and advantage of the present
invention is that it includes a large vacuum reservoir that can be
used to maintain vacuum in the cavity between the residual limb or
liner and the socket as air leaks into the cavity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] FIG. 1 is a side elevational view of the tissue and skeletal
structure of an amputee's residual limb;
[0046] 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;
[0047] 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;
[0048] FIG. 4 is a cross-section of the artificial limb in FIG. 3,
which is a first embodiment of the artificial limb;
[0049] FIG. 5 is a cross-section of the artificial limb similar to
FIG. 4, showing a second embodiment of the artificial limb;
[0050] FIG. 6 is the same as FIG. 5, but showing compression of the
inner socket under the influence of positive air pressure;
[0051] FIG. 7 is a cross-section of the artificial limb showing a
third embodiment of the artificial limb;
[0052] FIG. 8 is a cross-section of the artificial limb showing a
fourth embodiment of the artificial limb;
[0053] 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;
[0054] FIG. 10 is a cross-section of the artificial limb showing a
fifth embodiment of the artificial limb;
[0055] FIG. 11 is a cross-section of the artificial limb showing a
sixth embodiment of the artificial limb;
[0056] FIG. 12 is a detailed view of the vacuum mechanism in FIG.
11;
[0057] FIG. 13 is a cross-section of the artificial limb showing a
seventh embodiment of the artificial limb;
[0058] FIG. 14 is a detailed view of the vacuum mechanism and
suspension sleeve of FIG. 13;
[0059] FIG. 15 is a cross-section of the artificial limb showing an
eighth embodiment of the artificial limb;
[0060] FIG. 16 is a cross-section of the artificial limb showing a
ninth embodiment of the artificial limb;
[0061] FIG. 17 is a cross section of the artificial limb showing a
liner with an annular seal;
[0062] FIG. 18 is a cross-section of the artificial limb showing a
second embodiment of the liner of FIG. 17;
[0063] FIG. 19 is a partial cross-section of the artificial limb
showing a third embodiment of the liner of FIG. 17;
[0064] FIG. 20 is a partial cross-section of the artificial limb
showing a fourth embodiment of the liner of FIG. 17; and
[0065] FIG. 21 is a partial cross-section of the artificial limb
showing a liner with an adhering interface attaching the liner to
the inside of the socket.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0066] 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.
[0067] 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.
[0068] A vacuum source 70 may conveniently be attached to the shin
or pylon 54. The vacuum source 70 may preferably be a mechanical or
motor-driven pump 72. The vacuum source 70 is connected to a power
source 83, which may be a battery.
[0069] 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.
[0070] 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.
[0071] 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 outer socket 52 and a portion of the residual
limb 14. Alternatively, the seal means 84 maybe any type of seal
which is airtight.
[0072] 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.
[0073] 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.
[0074] 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.
[0075] 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.
[0076] 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 12. Next, the polyurethane
sleeve 86 is also rolled upwardly over the residual limb 10.
Thereafter, the liner 92 is optionally donned.
[0077] 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.
[0078] 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.
[0079] 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.
[0080] 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 (ideally fifteen to twenty
inches).
[0081] 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.
[0082] 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 loss of fluids from the residual limb caused by
weight-bearing pressures.
[0083] 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 (not shown), 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.
[0084] 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.
[0085] 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.
[0086] The mechanical 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 (not shown), which may
be a battery.
[0087] 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.
[0088] A fourth embodiment of the hypobarically-controlled
artificial limb 50 is shown in 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. Pat. No. 4,828,325, herein incorporated by
reference.
[0089] 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 603 may expand slightly under the weight of the
residual limb 14 and under the influence of vacuum.
[0090] 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 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.
[0091] 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.
[0092] 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.
[0093] The fourth embodiment may also include a thin sheath 90,
liner 92, and second sleeve 94, as previously described (see FIG.
3).
[0094] 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.
[0095] 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 71 may be a hand-operated vacuum pump 71 which may
remove air from the cavity 62 down to approximately 15-25 inches of
mercury. A suitable hand-operated vacuum pump is marketed under the
trademark MITY VAC IT.RTM. by Neward Enterprises, Inc. of
Cucamonga, Calif.
[0096] 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.
[0097] 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.
[0098] A sixth embodiment of the hypobarically-controlled
artificial limb of the present invention is shown in FIGS. 11 and
12. The sixth embodiment is like the first embodiment shown in FIG.
4, with some changes.
[0099] First, the inner socket is specifically intended to be
removably 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.
[0100] 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.
[0101] 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.
[0102] 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 the inner 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 inner
sheath 90 may also be used to assist the amputee into a smooth and
easy fitting into the inner socket 60.
[0103] 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 60 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.
[0104] 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.
[0105] 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.
[0106] In the sixth embodiment, the inner socket 60 has a rigid
lower portion 98 and a substantially flexible upper portion 96. The
rigid lower 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.
[0107] 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
{fraction (3/16)} inch below the top edge of the outer socket
52.
[0108] The sixth embodiment includes extensive modifications to the
vacuum system.
[0109] 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.
[0110] 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.
[0111] 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.
[0112] 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 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 106, providing a positive mechanical
interlock.
[0113] 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.
[0114] First, the mechanical interlock 103 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 104 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.
[0115] 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
U.S. Pat. No. 5,571,208, herein incorporated by reference.
[0116] The sleeve 86 preferably contains fabric threads which may
be oriented circumferentially around the sleeve. The threads
preferably are comprised of double-knit polyurethane. The threads
may also include nylon. The threads 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 may be slipped over
the inner socket 52. The threads are preferably connected together
with cross-links, which also may be preferably comprised of
polyurethane. The cross-links and threads form a matrix 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.
[0117] 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.
[0118] An eighth embodiment of the hypobarically-controlled
artificial limb of the present invention is shown in FIG. 15.
[0119] Unlike earlier embodiments, the artificial limb 50 of the
eighth embodiment has only a single socket 60 rather than inner and
outer sockets and is thus considerably simpler.
[0120] The socket 60 has a volume and shape to receive a
substantial portion of the residual limb 14 with a cavity 62
therebetween.
[0121] A nonfoamed, nonporous polyurethane liner 92 is preferably
adapted to receive the residual limb 14 and to be disposed between
the residual limb 14 and the socket 60.
[0122] A vacuum source 70 is connected to the cavity 62 by a vacuum
valve 78, thereby drawing the residual limb 14 into firm contact
with the socket 60.
[0123] A seal means 84 makes a seal between the residual limb 14
and the socket 60 to minimize air leakage into the cavity 62. It
has been found that it is impossible to make a perfect seal, with
the result that air leakage can occur at rates up to 30 cc per
minute. As air leaks into the cavity 62, it is necessary to
activate the vacuum source 70 to restore vacuum in the cavity.
Furthermore, it has been found that when the vacuum in the cavity
is about 5 inches of mercury, the residual limb may lose up to 6 to
15% of its volume during the day, whereas if the vacuum in the
cavity is 15-25 inches of mercury, the residual limb loses only
about 1% of its volume during the day.
[0124] To minimize the time that the vacuum source, such as a
vacuum pump 72, needs to run to maintain vacuum in the cavity, a
ninth embodiment of the artificial limb 50 is shown in FIG. 16. The
ninth embodiment is the same as the eighth embodiment, but a vacuum
reservoir 110 is added between the vacuum source 70 and the vacuum
valve 78. The vacuum reservoir 110 has a volume substantially
larger than the cavity 62. Suitably, the vacuum reservoir may have
a volume of 2 gallons or 9000 cc while the volume of the cavity 62
may be only about 100 cc or even less.
[0125] It will be seen that as air leaks into the cavity 62, the
air will be pulled into the vacuum reservoir 110, thereby
maintaining the vacuum in the cavity 62.
[0126] When the vacuum in the reservoir 110 reaches a certain
minimum threshold, the vacuum source 70 may be activated to restore
vacuum to the vacuum reservoir 110. The vacuum source 70 may be
activated either manually or by a regulator means (not shown).
[0127] The artificial limb 50 typically includes a shin or pylon 54
and a foot 56, as shown in FIG. 3. Preferably, the vacuum reservoir
110 is attached to the shin 54 between the socket 60 and the foot
56. However, the vacuum reservoir may also be carried separately,
as for example in a backpack. Depending on the placement of the
vacuum reservoir 110, a vacuum tube 76 may be necessary to connect
the vacuum reservoir 110 to the vacuum valve 78.
[0128] If the volume of the vacuum reservoir 110 is about 9000 cc
and air leaks into the cavity 62 at about 75 cc per minute, it will
be seen that the intervals between activation of the vacuum source
70 can be up to about 120 minutes.
[0129] The artificial limb 50 of the eighth and ninth embodiments
may preferably further comprise the following.
[0130] An inner sheath 90 may be adapted to be disposed between the
liner 92 and the socket, to ensure even distribution of vacuum in
the cavity 62, as earlier described. Preferably, the inner sheath
90 may be thin knitted nylon. The sheath 90 may also be affixed to
the outside of the liner 92.
[0131] The seal means 84 is preferably a nonfoamed, nonporous
polyurethane suspension sleeve 86 for rolling over and covering the
socket 60 and a portion of the artificial limb 14, as earlier
described. Seal means may also be an external annular abutting
flange or ring 140 shown in FIG. 17. Again, seal means may also be
an internal annular abutting flange or ring 140 shown in FIG.
18.
[0132] A stretchable nylon second sleeve 94 (see FIG. 3) for
rolling over and covering the suspension sleeve 86 may be added to
prevent clothing from sticking to and catching on the suspension
sleeve 86, as earlier described.
[0133] The vacuum source 70 is preferably a motor or mechanical
driven vacuum pump 72, as earlier described. A vacuum tube 76 may
be necessary to connect the vacuum pump 72 to the vacuum valve 78,
depending on the placement of the vacuum pump 72.
[0134] Applicant has found that many of the embodiments discussed
earlier share a common problem. The vacuum which holds the residual
limb (and liner) in firm contact with the socket tends to cause
edema and blistering at the point on the residual limb where the
suspension sleeve contacts the residual limb. This problem occurs
because the vacuum (perhaps 71/2 pounds of negative pressure) in
cavity 62 draws against the suspension sleeve 86 at the point where
the suspension sleeve 86 contacts the skin of the residual limb.
However, because the liner 92 often has an outer fabric cover 130
to prevent the liner from adhering to the socket 60 or clothing,
the suspension sleeve cannot make a good seal at the point where it
contacts the outer fabric cover 120. This has left the residual
limb as the only point at which to make the seal.
[0135] FIG. 17 shows one solution to this problem. The liner 92 is
improved by adding an annular seal 140 extending outwardly from the
fabric cover 130. The annular seal, which may be made from the same
material as the inner layer 92 of the liner, is adapted to
sealingly engage the suspension sleeve 86, producing a seal against
the vacuum in cavity 62 at the point of contact with the suspension
sleeve 86. Therefore, the vacuum in cavity 62 now draws against the
annular seal 130 rather than against the skin of the residual limb
14.
[0136] An alternative solution to the above problem is shown in
FIG. 18. Here, the annular seal 140 does not make contact with the
suspension sleeve 86, but rather makes contact with the inner wall
63 of the socket 60, and makes a seal at that point. No suspension
sleeve is used in this variation, it being found that sufficient
holding force is provided by the vacuum in cavity 62. FIG. 18 also
shows that the annular seal 140 may simply be an extension of the
liner 92, passing through the fabric cover 130.
[0137] A second alternative is shown in FIG. 19. This alternative
is like that of FIG. 18, with the exception that a mechanical
interlock 103 is provided which is adapted to interlock with the
socket 60. Preferably, as shown, the mechanical interlock 103
comprises a shuttle pin 108 adapted to connect the liner 92 with
the socket 60, and a locking mechanism 105 such as a second pin 110
extending through the socket 60 to the exterior of the socket 60
for access by the amputee as earlier described. More particularly,
the liner 92 may have an extension 104 or shuttle pin 108 embedded
in the liner at the distal end of the liner. Preferably, the
extension 104 has a portion 104A which may be a disk or umbrella
which engages a docking device 106 as earlier described.
[0138] To keep air from entering the cavity 62, the invention of
FIG. 19 also preferably includes a locking mechanism seal 150
adapted to engage the inner wall 63 of the socket 60 about the
locking mechanism 105. The seal 150 could alternatively be on the
outer surface of the socket 60.
[0139] Another alternative is shown in FIG. 20. Here, the fabric
cover 130 stops below the annular seal 140. The annular seal 140
may also be made of the same material as the liner 92.
[0140] Applicant has found that, by bonding the liner 92 directly
to the inside surface 63 of the socket 60, a seal may be produced
that maintains the vacuum in the cavity 62 without the need for a
separate annular seal or vacuum seal. FIG. 21 shows this
embodiment.
[0141] In FIG. 21, the liner 92 is bonded directly to the inside
surface 63 of the socket 60 by an adhering interface 64.
[0142] The adhering interface 64 may be such as to provide a
permanent attachment of the liner 92 to the socket 60, or a
semi-permanent attachment that allows the liner 92 to be removed
and replaced.
[0143] The adhering interface 64 may be any interface that has two
adhering surfaces. One adhering surface 64a preferably adheres to
the liner 92 while the other adhering surface 64b preferably
adheres to the inside surface 63 of the socket 60.
[0144] Possible embodiments of a permanent attachment for the
adhering interface 64 are: a laminating adhesive, i.e., a thin film
placed on the surface of the liner and the liner 92 then being
inserted into the socket 60; contact cement; or any type of
paint-on glue.
[0145] Possible embodiments of a semi-permanent attachment for the
adhering interface 64 are: a hook and loop fastener fabric such as
Velcro.RTM.; or cooperating magnets in both the liner 92 and the
socket 60.
[0146] To don the artificial limb, the wearer inserts the residual
limb into the liner, which is already attached to the socket by the
adhering interface.
[0147] Additional connections may be employed between the residual
limb and the socket, such as the nonfoamed, nonporous polyurethane
suspension sleeve earlier described and the mechanical interlock
also previously described.
[0148] 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.
* * * * *