U.S. patent application number 11/883211 was filed with the patent office on 2008-12-11 for prosthesis and method of manufacturing a prosthesis.
This patent application is currently assigned to SMART IMPLANT PLC. Invention is credited to Jonathan Hamilton.
Application Number | 20080306590 11/883211 |
Document ID | / |
Family ID | 36693939 |
Filed Date | 2008-12-11 |
United States Patent
Application |
20080306590 |
Kind Code |
A1 |
Hamilton; Jonathan |
December 11, 2008 |
Prosthesis and Method of Manufacturing a Prosthesis
Abstract
A prosthesis is disclosed which includes a filler material
comprising a biocompatible granular substance. The prosthesis
includes in a particular embodiment a human mammary prosthesis. The
granular substance comprises a mixture of synthetic biocompatible
cells and a lubricant. Also disclosed is an osmotic barrier which
reduces the flow of lubricant from the prosthesis and the flow of
body fluids into the prosthesis.
Inventors: |
Hamilton; Jonathan;
(Honeydew, ZA) |
Correspondence
Address: |
MARSHALL, GERSTEIN & BORUN LLP
233 S. WACKER DRIVE, SUITE 6300, SEARS TOWER
CHICAGO
IL
60606
US
|
Assignee: |
SMART IMPLANT PLC
London
GB
|
Family ID: |
36693939 |
Appl. No.: |
11/883211 |
Filed: |
January 27, 2006 |
PCT Filed: |
January 27, 2006 |
PCT NO: |
PCT/IB06/00139 |
371 Date: |
April 4, 2008 |
Current U.S.
Class: |
623/8 |
Current CPC
Class: |
A61L 27/18 20130101;
C08L 83/04 20130101; A61L 27/18 20130101; A61L 27/50 20130101; A61F
2/12 20130101 |
Class at
Publication: |
623/8 |
International
Class: |
A61F 2/12 20060101
A61F002/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 29, 2005 |
ZA |
2004/8765 |
Jan 29, 2005 |
ZA |
2004/10188 |
Apr 20, 2005 |
ZA |
2005/3184 |
May 27, 2005 |
ZA |
2005/04333 |
Aug 22, 2005 |
ZA |
2005/06704 |
Sep 14, 2005 |
ZA |
2005/07390 |
Oct 21, 2005 |
ZA |
2005/08552 |
Nov 17, 2005 |
ZA |
2005/09314 |
Claims
1. A human prosthesis comprising a resilient shell at least partly
filled with a plurality of biocompatible synthetic cells of which
each cell has a lenticular shape.
2. A prosthesis as claimed in claim 1 which comprises a human
mammary prosthesis.
3. A prosthesis as claimed in claim 1 in which the cells are
manufactured from a resilient material.
4. A prosthesis as claimed in claim 3 in which the resilient
material comprises a medical grade silicone.
5. A prosthesis as claimed in claim 1 in which a plurality of micro
glass balloons are dispersed in each cell.
6. A prosthesis as claimed in claim 5 which includes between 2% and
10% micro glass balloons by volume, preferably between 4% and 8%
micro glass balloons by volume, more preferably between 5% and 7%
micro glass balloons by volume, and most preferably about 6% micro
glass balloons by volume.
7. A prosthesis as claimed in claim 1 in which the cells have a
range of sizes.
8. A prosthesis as claimed in claim 1 in which each cell has a
circular diameter of about 6 mm and a height of about 2 mm.
9. A prosthesis as claimed in claim 1 in which each cell comprises
a hollow capsule encapsulating a fluid.
10. A prosthesis as claimed in claim 9 in which the fluid comprises
a biocompatible fluid, perferably oil.
11. A prosthesis as claimed in claim 10 in which the oil comprises
a vegetable oil, preferably soy bean oil.
12. A prothesis as claimed in claim 9 in which the fluid comprises
a gas, perferably compressed air, more preferably sterilized
air.
13. A prosthesis as claimed in claim 1 in which the cells has a
wall thickness of about 0.1 mm.
14. A prosthesis as claimed in claim 1 in which each cell includes
a tracer adapted to be detectable by means of external diagnostic
equipment.
15. A prosthesis as claimed in claim 14 in which the tracer
comprises a metal particle contained in the cell, perferably a
titanium particle.
16. A prosthesis as claimed in claim 1 in which the cells are
located within a biocompatable lubricant.
17. A prosthesis as claimed in claim 1 in which the shell includes
a filling aperture which comprises a recessed portion in the shell
within which a complimentary seal is securable to seal the bladder
by means of silicone glue, the seal comprises a membrane and a
plug, and the membrane is securable to the operative base of the
recess and the plug is securable onto the membrane in the
recess.
18. A prosthesis as claimed in claim 17 in which the membrane has a
thickness of about 0.1 mm and the plug has a thickness of about 0.9
mm.
19. A prosthesis as claimed in claim 17 in which the plug and the
membrane are manufactured from the same material as the shell,
perferably a medical grade silicone.
20. A prosthesis as claimed in claim 17 in which the shell
surrounding the recess is thickened such that the operatively inner
surface of the shell inside of the aperture is substantially
step-less.
21. A prosthesis as claimed in claim 1 in which the shell comprises
at least one resilient layer and at least one layer being
substantially non-permeable with respect to at least the filler
material of the shell.
22. A prosthesis as claimed in claim 21 in which the resilient
layer comprises a sealed operatively outer container and the
non-permeable layer comprises a sealed operatively inner
containers, the inner containers contain the filler material, and
the outer container contains the inner containers.
23. A prosthesis as claimed in claim 22 which includes a lubricant
between the inner container and outer containers.
24. A prosthesis as claimed in claim 22 in which the surface area
of the inner container is larger than the surface of the outer
container, preferably at least twice as large as the surface of the
outer container, and more preferably at least as large as the
maximum size to which the outer container may be stretched
elastically.
25. A prosthesis as claimed in claim 21 in which the non-permeable
layer comprises a composite layer which includes a nylon layer
located between a polyester and polyethylene layer.
26. A prosthesis as claimed in claim 25 in which the lubricant
within which the cells are located includes a hydrophilic
polymer.
27. A prosthesis as claimed in claim 26 in which the hydrophilic
polymer comprises a water soluble polymer or hydrogel.
28. A prosthesis as claimed in claim 27 in which the water soluble
polymer or hydrogel comprises a polyvinyl pyrrolidone (PVP).
29. A prosthesis as claimed in claim 26 in which the hydrophilic
polymer is mixed with a saline solution, and preferably comprises
about 15% hydrophilic polymer and about 85% saline.
30. A prosthesis as claimed in claim 21 in which the non-permeable
layer comprises a composite polyethylene and aluminium layer.
31. A prosthesis as claimed in claim 30 in which the aluminium
layer comprises a vapour deposited layer of aluminium on the
polyethylene layer, and the aluminium layer preferably has a
thickness in the range of about 12 micron to 18 micron.
32. A prosthesis as claimed in claim 30 in which the lubricant
includes glycerine, or a combination of water and glycerine.
33. A prosthesis as claimed in claim 21 in which the non-permeable
layer has a thickness of between about 20 micron and about 70
micron, perferably a thickness of between about 40 micron and about
55 micron, and more preferably a thickness of about 48 micron.
34. A prosthesis as claimed in claim 1 in which the biocompatible
synthetic cells which fills the shell is contained in an inner
container comprising a biocompatible resilient mesh.
35. A prosthesis as claimed in claim 1 which includes
identification means bearing data relating to at least the size of
the prosthesis by means of a unique number which is relatable to
unique data stored in a database, and for the identification means
to include a remotely activatable data transponder configured to
transmit a predetermined data carrying signal in response to remote
activation thereof means of an energy field.
36. A prosthesis as claimed in claim 1 in which the filler material
comprises between about 80% and 97.5% of the non-stretched volume
of the shell.
37. A prosthesis as claimed in claim 53 in which a prosthesis
having a volume between 200 cm.sup.3 and 450 cm.sup.3 includes the
respective weight of cells and weight of polyvinyl pyrrolidone
(PVP)/saline solution mixture in the inner container as shown in
the table: TABLE-US-00007 Prosthesis Volume (cm.sup.3) Cells (g)
PVP mixture (g) 200 82.352 82.352 225 92.646 92.646 250 102.94
102.94 275 113.234 113.234 300 123.528 123.528 325 133.822 133.822
350 144.116 144.116 375 154.41 154.41 400 164.704 164.704 425
174.998 174.998 450 185.292 185.292
38. A prosthesis as claimed in claim 29 in which a prosthesis
having a volume between 200 cm.sup.3 and 450 cm.sup.3 includes the
respective weight of cells and weight of polyvinyl pyrrolidone
(PVP)/saline solution mixture in the inner container as shown in
the table: TABLE-US-00008 Prosthesis Volume (cm.sup.3) Cells (g)
PVP mixture (g) 200 87.5 87.5 225 98.4375 98.4375 250 109.375
109.375 275 120.3125 120.3125 300 131.25 131.25 325 142.1875
142.1875 350 153.125 153.125 375 164.0625 164.0625 400 175 175 425
185.9375 185.9375 450 196.875 196.875
39. A prosthesis as claimed in claim 29 in which a prosthesis
having a volume between 200 cm.sup.3 and 450 cm.sup.3 includes the
respective weight of cells and weight of polyvinyl pyrrolidone
(PVP)/saline solution mixture in the inner container as shown in
the table: TABLE-US-00009 Prosthesis Volume (cm.sup.3) Cells (g)
PVP mixture (g) 200 95 95 225 106.875 106.875 250 118.75 118.75 275
130.625 130.625 300 142.5 142.5 325 154.375 154.375 350 166.25
166.25 375 178.125 178.125 400 190 190 425 201.875 201.875 450
213.75 213.75
40. A method of filling a shell of a human mammary prosthesis, as
claimed in claim 1, with a filler material, which includes the
steps of filling the shell with a predetermined number of
biocompatible synthetic cells, securing a complimentary shaped
membrane to an aperture in the shell, inserting a needle into the
shell through the membrane, injecting a predetermined amount of a
liquid biocompatible lubricant through the needle into the shell,
retracting the needle, and sealing the filler aperture with a
complimentary shaped seal.
41. A method as claimed in claim 40 which includes evacuating
substantially all air from the shell prior to injecting the
lubricant into the shell.
42. A method of filling a shell of a human mammary prosthesis, as
claimed in claim 1, with a filler material, which includes the
steps of filling an inner container as claimed in claim 40 with a
predetermined number of biocompatible synthetic cells and a
predetermined volume of liquid lubricant, sealing the inner
container, inserting the inner container into an outer container as
claimed in claim 22, securing a complimentary shaped membrane to an
aperture in the shell, inserting a needle into the shell through
the membrane, injecting a predetermined amount of a liquid
biocompatible lubricant through the needle into the shell,
retracting the needle, and sealing the filler aperture with a
complimentary shaped seal.
43. A method as claimed in claim 42 which includes evacuating
substantially all air from the shell prior to injecting the
lubricant into the shell.
44. A prosthesis as claimed in claim 1, in which the shell has a
predetermined shaped corresponding to that of a breast.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a prosthesis and a method of
manufacturing a prosthesis in particular but not limited to a
mammary prosthesis.
BACKGROUND TO THE INVENTION
[0002] Mammary prostheses are used to enhance the appearance of
human breasts, normally female breasts. The prostheses are used to
add volume to a breast which may be required after removal of a
tumour, or to enhance the aesthetic appeal of a breast.
[0003] A mammary prosthesis typically comprises a resilient
plastics material bladder which is filled with a liquid. The
bladder is normally manufactured from a silicone rubber filled with
a gel, typically a silicone gel.
[0004] A problem with silicone gel is rupturing of the bladder
which releases the gel in the patient's body. If a bladder ruptures
in vitro the released gel cannot be recovered, or at least not all
of it.
[0005] A serious complication of silicone gel filled bladder
prostheses is capsular contraction, which is a condition in which
tissue surrounding the prosthesis after it has been implanted into
a patient hardens. This hardening of the tissue takes place in
response to silicone gel which routinely leaks through the bladder.
The leaking is an accepted side effect of these prostheses and
capsulation is, in part, relied upon to contain silicone which
leaks from the bladder.
[0006] One likely driving force for the bleed of the filler
material, and specifically silicone gel, is Brownian motion, which
is a result of thermal molecular motion of particles in a liquid
environment. According to this phenomenon, there is random movement
of the silicone gel particles inside the shell of the prosthesis.
Since the atomic structure of solid silicone, from which the shell
of the prosthesis is manufactured, is larger than the size of
silicone gel molecules, some of the gel molecules will pass through
the shell because of the Brownian motion. In essence, the shell is
like a mesh through which the gel particles can be squeezed.
[0007] Another phenomenon which also likely acts as a driving force
is osmotic pressure. According to Merriam-Webster's Collegiate
Dictionary, osmosis is the "movement of a solvent through a
semi-permeable membrane (as of a living cell) into a solution of
higher solute concentration that tends to equalize the
concentrations of solute on the two sides of the membrane." In the
case of a silicone gel filled mammary prosthesis, there is a higher
concentration of gel inside the shell of the prosthesis than
outside the shell. Body fluid, of which there is plenty in supply,
will tend to move into the prosthesis because of osmotic pressure
in an attempt to equalize the concentrations of silicone gel on
opposite sides of the shell. This increases the fluid pressure
inside the prosthesis which contributes as a driving force to push
fluids out of the prosthesis, including silicone gel. At the same
time the silicone gel, which is at a higher concentration inside
the shell than in the human body and is at least to some degree a
solute, experiences osmotic pressure to move from a higher
concentration to a lower concentration through the shell, i.e. from
the prosthesis into the body.
[0008] There have been attempts to limit the spread of the silicone
by formulating it as a `sticky` gel. The intention with this is to
keep the silicone gel together and to ease surgical removal.
However, this does not solve the problem since the sticky gel
adheres to anything it touches including the patient's organs and
the surgeon's gloves. Removing the sticky gel is not an easy matter
and 100% removal of all leaked gel is generally not possible.
[0009] In some countries, the use of bladders filled with silicone
gel has been banned due to the health risks associated with it. To
overcome this problem prostheses have been developed which comprise
a bladder filled with liquid other than silicone gel, for example
saline solution. This solves the problem of the leaking which
causes capsular contraction. If such a prosthesis ruptures the
patient doesn't need surgery to remove the liquid, since saline is
harmless to the human body.
[0010] A problem associated with saline filled prostheses is that
these prostheses are generally inserted empty into a patient and
filled in vitro by means of a filler tube and non return valve.
These systems are often problematic and leakage of saline through
the filler tube arrangement often occurs.
[0011] Another problem with saline filled prostheses is that the
viscosity of saline is different from silicone gel, which causes
these prostheses to have an unnatural feel once implanted.
[0012] Another problem with conventional prostheses is that details
of implanted prostheses are not readily ascertainable from outside
the body. In some instances it is necessary to determine details,
such as size and type of implant or the date on which the
prostheses was implanted on short notice and preferably without
surgical procedure. Such instances may include a medical emergency
such as may arise following an accident. It may also occur during
routine procedures.
[0013] It often happens that people are unable to convey details of
a prosthesis to medical personnel which may leave the medical
personnel with no option but to determine details of the implanted
prosthesis by means of expensive scanning equipment, for example
MRI scanning, or surgery. Neither of these is desirable, the first
due to the cost involved and second due to the invasive and drastic
nature and the cost thereof.
[0014] A specific problem exists with female patients whom had
received breast augmentation surgery and experience complications.
In many instances, these patients are not able to recall the make
of prosthesis they have received and in even more cases, not the
size of prosthesis received. If an existing prosthesis needs to be
replaced the surgeon needs to have all possible sizes available
during surgery to fit the correct size prosthesis.
[0015] A further aspect of breast prostheses that is problematic
relates to the manufacturing of the prostheses. In most cases a
bladder is formed which include an opening at the operatively
posterior side of the bladder. This opening is needed in the
forming of the bladder to enable removal from the mould on which
the bladder is formed. The opening is sealed by means of a disc
which is placed inside the opening and adhered to the bladder by
means of pressure. A problem with this type of seal is that it is
not a seal that is formed by means of a bond between the two
surfaces forming part of the seal, but rather an adhesion type seal
of the disc against the bladder which, after the bladder has been
filled, relies on pressure from the gel inside the bladder to
maintain the seal. It is possible to disengage such a seal by
exerting on the disc from the outside.
[0016] The above mentioned problems have been exemplified by way of
a mammary prosthesis, but similar problems exist with other types
of prostheses. Examples of these include prostheses which are used
to enhance the appearance of buttocks, cheeks, and biceps. The
concerns about the safety of silicone gel filled prostheses are
equally applicable to these procedures, as are problems which exist
with saline filled prostheses.
OBJECT OF THE INVENTION
[0017] It is an object of the invention to provide a prosthesis
which at least partly overcomes the abovementioned problem.
SUMMARY OF THE INVENTION
[0018] In accordance with this invention there is provided a human
prosthesis comprising a resilient shell at least partly filled with
a biocompatible granular substance, and preferably for the
prosthesis to comprise a human mammary prosthesis.
[0019] There is further provided for the granular substance to
comprise a plurality of biocompatible synthetic cells, preferably
cells manufactured from a resilient material, and preferably for
the resilient material to comprise a medical grade silicone.
[0020] There is further provided for a plurality of micro glass
balloons to be dispersed in each cell, preferably between 2% and
10%, further preferably between 4% and 8%, still further preferably
between 5% and 7%, and more preferably about 6% micro glass
balloons by volume.
[0021] There is further provided for the micro-balloons to comprise
commercially available micro-balloons with a diameter of about 1
micron each.
[0022] There is also provided for each cell to have a lenticular
shape, alternatively an ovoid or a bean shape and for the shell to
be filled, at least partly, with cells having a range of sizes.
[0023] According to an preferred embodiment of the invention each
cell having a lenticular shape has a circular diameter of about 6
mm and a height of about 2 mm.
[0024] According to a further feature of the invention there is
provided for each cell to comprise a hollow capsule encapsulating a
fluid, preferably a biocompatible fluid, further preferably oil,
still further preferably a vegetable oil, and yet further
preferably soy bean oil; alternatively a biocompatible gas, further
preferably air, still further preferably sterilized air.
[0025] There is still further provided for each hollow cell to have
a wall thickness of about 0.1 mm.
[0026] A further feature of the invention provides for each cell to
include at least one tracer adapted to be detectable by means of
external diagnostic equipment.
[0027] There is further provided for the cells to be located within
a lubricant, preferably a biocompatible lubricant.
[0028] According to a still further feature there is provided for
the shell of the prosthesis to include a filling aperture, for the
aperture to comprise a recessed portion in the shell, preferably a
circular recess, and for a complimentary circular seal to be
securable in the recess to seal the shell.
[0029] There is still further provided for the circular seal to be
securable to the shell by means of glue, preferably silicone
glue.
[0030] There is still further provided for the recess to include a
right circular cylindrical outer wall and for the seal to include a
complimentary right circular cylindrical circumference.
[0031] There is still further provided for the seal to comprise a
membrane and a plug.
[0032] There is further provided for the membrane to be securable
to the operative base of the recess and for the plug to be
securable onto the membrane in the recess.
[0033] There is still further provided for the membrane to have a
thickness of about 0.1 mm and for the plug to have a thickness of
about 0.9 mm.
[0034] There is also provided for the plug and the membrane to be
manufactured from the same material as the shell, preferably a
medical grade silicone material.
[0035] There is also provided for the shell surrounding the recess
to be thickened such that the operatively inner surface of the
shell inside of the aperture is substantially step-less.
[0036] The invention also provides for the mammary prosthesis to
comprise a shell which contains a filler material, for the shell to
comprise at least one resilient layer and at least one layer being
substantially non-permeable with respect to at least the filler
material of the shell; and for the filler material to comprise,
preferably a biocompatible granular substance, alternatively a
fluid filler material, in particular a silicone gel or a saline
based fluid.
[0037] There is further provided for the resilient layer to
comprise a sealed operatively outer container, for the
non-permeable layer to comprise a sealed operatively inner
container which contains the filler material and for the inner
container to be contained by the outer container, and preferably
for the prosthesis to include a lubricant between the inner
container and outer container.
[0038] There is still further provided for the non-permeable layer
to be non-permeable also with respect to body fluids.
[0039] There is still further provided for the surface area of the
inner container to be greater than the surface area of the outer
container, and preferably at least twice as large, alternatively
for the surface area of the inner container to be at least as great
as the maximum surface area to which the outer container may be
stretched elastically.
[0040] According to a further feature of the invention there is
provided for the non-permeable layer to comprise a composite layer,
and for the composite layer to comprise a nylon layer located
between a polyester and polyethylene layer.
[0041] There is still further provided for the lubricant within
which the cells are located to include a hydrophilic polymer,
preferably a water soluble polymer or hydrogel, and further
preferably polyvinyl pyrrolidone (PVP), and for the non-permeable
layer to include at least a polyethylene layer.
[0042] There is further provided for the hydrophilic polymer to be
mixed with a saline solution, and preferably for the lubricant to
comprise about 15% hydrophilic polymer and about 85% saline
solution.
[0043] There is still further provided for the prosthesis in one
embodiment to have a volume between 200 cm.sup.3 and 450 cm.sup.3
and to include the respective weight of cells and weight of
polyvinyl pyrrolidone (PVP)/saline solution mixture in the inner
container as shown in the table:
TABLE-US-00001 Prosthesis PVP mixture volume (cm.sup.3) Cells (g)
(g) 200 82.352 82.352 225 92.646 92.646 250 102.94 102.94 275
113.234 113.234 300 123.528 123.528 325 133.822 133.822 350 144.116
144.116 375 154.41 154.41 400 164.704 164.704 425 174.998 174.998
450 185.292 185.292
[0044] There is also provided for the prosthesis in a further
embodiment to have a volume between 200 cm.sup.3 and 450 cm.sup.3
and to include the respective weight of cells and weight of
polyvinyl pyrrolidone (PVP)/saline solution mixture in the inner
container as shown in the table:
TABLE-US-00002 Prosthesis PVP mixture volume (cm.sup.3) Cells (g)
(g) 200 87.5 87.5 225 98.4375 98.4375 250 109.375 109.375 275
120.3125 120.3125 300 131.25 131.25 325 142.1875 142.1875 350
153.125 153.125 375 164.0625 164.0625 400 175 175 425 185.9375
185.9375 450 196.875 196.875
[0045] There is also provided for the prosthesis in a yet further
embodiment to have a volume between 200 cm.sup.3 and 450 cm.sup.3
and to include the respective weight of cells and weight of
polyvinyl pyrrolidone (PVP)/saline solution mixture in the inner
container as shown in the table:
TABLE-US-00003 Prosthesis PVP mixture volume (cm.sup.3) Cells (g)
(g) 200 95 95 225 106.875 106.875 250 118.75 118.75 275 130.625
130.625 300 142.5 142.5 325 154.375 154.375 350 166.25 166.25 375
178.125 178.125 400 190 190 425 201.875 201.875 450 213.75
213.75
[0046] According to further feature of the invention there is
provided for the non-permeable layer to comprise a composite layer
which comprises at least a composite polyethylene and aluminium
layer, for the lubricant to include glycerine, and preferably for
the lubricant to comprise a combination of water and glycerine.
[0047] There is still further provided for the for the aluminium
layer to be a vapour deposited layer on the polyethylene layer and
for the vapour deposited aluminium layer to have a thickness in the
range of about 12 micron to 18 micron.
[0048] There is also provided for the non-permeable layer to have a
thickness of between about 20 micron and about 70 micron,
preferably between about 40 micron and 55 micron, more preferably
to have a thickness of about 48 micron.
[0049] According to a yet further feature of the invention there is
provided for the granular substance which fills the prosthesis to
be contained in an inner container, preferably manufactured from a
biocompatible resilient mesh.
[0050] According to a still further feature of the invention there
is provided for the outer container to contain a plurality of inner
containers, for each of the plurality of inner containers to
contain a plurality of cells, and for each inner container to
comprise a non-permeable layer including a nylon layer located
between a polyester and polyethylene layer and within which the
plurality of cells are located in a hydrophilic polymer lubricant;
alternatively for each inner container to comprise a non-permeable
layer including at least a composite polyethylene and aluminium
layer within the plurality of cells are located in a lubricant
which includes glycerine, preferably a lubricant which comprises a
combination of water and glycerine.
[0051] According to a yet further feature of the invention the
shell has a predetermined shaped corresponding to that of a
breast.
[0052] According to an alternative feature of the invention there
is provided for the tracer to comprise a metal particle, preferably
a titanium particle, contained in the cell.
[0053] There is also provided for the prosthesis to include
identification means bearing data relating to at least the size of
the prosthesis, preferably the number of cells contained within the
prosthesis, and further preferably for the identification means to
comprise an identification tab on which the data is printed.
[0054] According to a further feature of the invention, there
provided for the prosthesis to include a remotely activatable data
transmission device configured to transmit a predetermined data
carrying signal in response to remote activation thereof.
[0055] There is further provided for the transmission device to
comprise a data transponder, preferably in the form of a Radio
Frequency Identification (RFID) tag, and for the RFID to be
remotely activatable by means of an energy field, preferably a
magnetic field.
[0056] There is still further provided for the prosthesis to
comprise a human mammary prosthesis, for the prosthesis to comprise
a biocompatible resilient container filled with a biocompatible
granular substance and at least one data transmission device,
preferably an RFID tag.
[0057] There is still further provided for the RFID tag to be
incorporated into a cell of the granular substance, alternatively
for the RFID tag to be incorporated into the shell, further
alternatively to be incorporated into the filler opening seal of
the shell.
[0058] There is also provided for the prosthesis to be manufactured
in a range of sizes and for each size to include a predetermined
number of cells.
[0059] In accordance with a further feature of the invention there
is provide a method of manufacturing cells for use in a human
mammary prosthesis as defined above, the method comprising coating
two plates, which each has a plurality of cavities therein and in
which each cavity corresponds to a semi-portion of a cell, with a
liquid resilient material, arranging the two plates to align each
individual cavity of one plate with another individual cavity of
the other plate, allowing the resilient material to set, removing
the plates from each other, and removing cells formed between the
formations from the plates.
[0060] There is also provided for the method to include placing a
tracer in one semi-portion of each cell prior to arranging the
plates together.
[0061] There is still further provided for the method to include
trimming excess resilient material located around the circumference
of each cell, and preferably for the excess material to be trimmed
by integral trimming formations in at least one of the plates, each
trimming formation surrounding a half-portion cavity and being
shaped and configured to press against the surface of the opposing
plate upon aligning of the plates to trim excess resilient material
from the formed cell.
[0062] According to a further feature of the invention there is
provided a method of filling a shell for a human mammary prosthesis
with a filler material, comprising the steps of securing a
complimentary shaped membrane to an aperture in the shell,
inserting a needle into the shell through the membrane, injecting a
predetermined amount of a liquid biocompatible lubricant through
the needle into the shell, retracting the needle, and sealing the
filler aperture with a complimentary shaped seal.
[0063] There is also provided for the method to include the step of
filling the shell with a plurality of biocompatible resilient
cells, prior to securing the membrane to the filler aperture, and
thereafter injecting a predetermined amount of the liquid lubricant
through the needle, preferably a glycerine and water mixture.
[0064] There is further provided for a method of filling a shell of
a human mammary prosthesis which includes the steps of filling an
inner container, as defined above, with a predetermined number of
biocompatible synthetic cells and a predetermined volume of liquid
lubricant, sealing the inner container, inserting the inner
container into an outer container, as defined above, securing a
complimentary shaped membrane to an aperture in the shell,
inserting a needle into the shell through the membrane, injecting a
predetermined amount of a liquid biocompatible lubricant through
the needle into the shell, retracting the needle, and sealing the
filler aperture with a complimentary shaped seal.
[0065] There is also provided for the method to include evacuating
substantially all air from the shell prior to injecting the
lubricant into the shell.
BRIEF DESCRIPTION OF THE DRAWINGS
[0066] Embodiments of the invention are described by way of example
only and with reference to the accompanying drawings in which:
[0067] FIG. 1 is a sectional view of a first embodiment of a human
mammary prosthesis according to the invention;
[0068] FIG. 2 is a sectional view of a biocompatible synthetic cell
of the prosthesis of FIG. 1;
[0069] FIG. 3 is a sectional view of the prosthesis of FIG. 1
implanted into a female breast;
[0070] FIG. 4 is shows a sectional view of a second embodiment of a
human mammary prosthesis according to the invention which includes
an inner container;
[0071] FIG. 5 is a sectional view of a first embodiment of a
laminate used for the inner container of the prosthesis of FIG.
4;
[0072] FIG. 6 is a sectional view of a second embodiment of layers
used for the inner and outer containers of a human mammary
prosthesis according to the invention;
[0073] FIG. 7 is a sectional view of a second embodiment of layers
used for the inner and outer containers of a human mammary
prosthesis according to the invention;
[0074] FIG. 8 is a sectional view of a third embodiment of a human
mammary prosthesis according to the invention;
[0075] FIG. 9 is a sectional view of a fourth embodiment of a human
mammary prosthesis according to the invention;
[0076] FIGS. 10 to 14 are sectional views showing one embodiment of
a method of filling a human mammary prosthesis according to the
invention;
[0077] FIG. 15 is a sectional view of a mould used to manufacture
biocompatible synthetic cell according to the invention; and
[0078] FIG. 16 shows detail of a part of the mould of FIG. 15.
DETAILED DESCRIPTION OF THE INVENTION
[0079] A first embodiment of a human mammary prosthesis (1)
according to the invention is shown in the drawings. The prosthesis
(1) shown in FIG. 1 comprises a resilient shell (2) filled with a
granular substance which in this embodiment is a plurality of cells
(3). The shell (2) also includes a lubricant (4) amongst the cells
(3).
[0080] The cells (3) are manufactured from a biocompatible
synthetic and resilient material, namely a silicone rubber. As
shown in FIG. 2 each cell (3) has a lenticular shape having a
circular diameter of about 6 mm and a height of about 2 mm.
[0081] Each cell (3) includes a plurality of micro glass balloons
(not shown) dispersed throughout it. These hollow micro glass
balloons are minute in size, each measuring only about one micron
in diameter. The micro balloons are mixed into the silicone rubber
from which the cells (3) are manufactured and remains dispersed
therein. This means the micro glass balloons cannot migrate from
the cells (3).
[0082] The micro glass balloons are included at about 6% by volume,
although it has been established that inclusion of micro balloons
in the range of between 2% and 10%, between 4% and 8%, and between
5% and 7% also yields acceptable results.
[0083] The micro balloons are included in the cells (3) to render
the cells (3) visible during medical examination. The medical grade
silicone rubber, from which the cells (3) are manufactured, are
normally relatively transparent, not only to the human eye but also
to X-rays. The inclusion of the micro glass balloons renders the
cells (3) opaque and visible during a breast examination. This is
important since an examining physician may want to be certain that
he does not confuse the cells (3) of the prosthesis (1) with a lump
in the breast. By making the cells (3) visible under an X-ray the
physician can clearly identify the cells (3).
[0084] The inclusion of the micro glass balloons also serves
another purpose. In the event of the prosthesis (1) rupturing and
some of the cells (3) escaping from the shell (2), the cells (3)
may be located easily by making use of an X-ray or MRI scanner.
[0085] The prosthesis (1) includes a filling aperture (5) which is
closed with a circular seal (6). The filling aperture (5) comprises
a circular recessed portion (7) in the shell (2). The seal (6) is
circular and is securable in the recess (7) to seal the shell (2).
The seal (6) is secured to the shell (2) by means of a silicone
glue.
[0086] The seal (6) includes two layers, which includes a membrane
(8) and a plug (9). The membrane (8) is first secured the shell (2)
at the base of the recess (7), after which the plug (9) is secured
onto the membrane (8). The membrane (8) and plug (9) are
manufactured from the same medical grade silicone rubber as the
shell (2) and the cells (3).
[0087] As can be seen in FIG. 1 the shell (2) is thickened (10) in
the area surrounding the recess (7) such that the operatively inner
surface (11) of the shell (2) around the aperture (5) is
substantially step-less. This is to keep the inner surface (11) of
the shell (2) smooth to ensure unimpeded movement of the cells (3)
inside the shell (2).
[0088] In use the prosthesis (1) is implanted in the normal manner
into a female patient's breast (12), as shown in FIG. 3. The
prosthesis (1) is surgically implanted using normal surgical
techniques. In this embodiment, the prosthesis (1) is implanted
underneath the breast tissue (13) in the pectoral muscle (14), but
it may also be implanted above the pectoral muscle (14) as is
commonly done in human mammary prosthesis procedures.
[0089] The prosthesis (1) is implanted with the filling aperture
(5) and seal (6) at the operatively back of the prosthesis (1), to
eliminate the chance of this thicker portion of the prosthesis (1)
being felt through the breast tissue (13) of the patient.
[0090] The prosthesis (1) provides more of a natural feel to the
breast (12) than conventional saline or gel filled prostheses do.
This is due to the lubricated silicone cells (3) which are free to
move around inside the shell (2) and which mimics natural breast
tissue.
[0091] The prosthesis (1) is manufactured to a specific
predetermined size, and includes a known predetermined number of
cells (3).
[0092] A second embodiment of a human mammary prosthesis (20)
according to the invention is shown in FIG. 4. This prosthesis (20)
includes a resilient shell (21), which forms an outer container,
and within which an inner container (22) is located. The inner
container (22) contains a plurality of the biocompatible synthetic
cells (23), as shown in FIG. 2, and a lubricant (24).
[0093] The inner container (22) of the prosthesis of FIG. 4
comprises a laminate, as shown in FIG. 5, of a nylon layer (25)
which is sandwiched between polyester layer (26) and a polyethylene
layer (27). This composite inner layer (28) which forms the inner
container (22) is non-permeable to at least the filler material
(29) of the prosthesis (20) and body fluids of the recipient of the
prosthesis (20).
[0094] The prosthesis of FIG. 4 includes a lubricant in the form of
a glycerine based lubricant (24), which lubricates the cells (23)
within the inner container (22). The inner layer (28) is effective
in limiting the passage of the lubricant (24) from the prosthesis
(20) to the body of a recipient thereof. It also limits the ingress
of body fluids from the recipient into the prosthesis (20). The
inner layer (28) therefore acts as an osmotic barrier which reduces
the osmotic driving force which seeks to balance the concentrations
of solutes on opposite sides of the barrier, in this case the shell
(21), of the prosthesis (20).
[0095] A second embodiment of a construction of inner and outer
containers for a prosthesis according to the invention is shown in
FIG. 6. In this embodiment the prosthesis (not shown) includes a
filler material in the form of a plurality of cells (30) in a
polyvinyl pyrrolidone (PVP) based lubricant (31). The latter (31)
acts as a lubricant for the cells (30) within the inner container
(32). The PVP is a water soluble polymer and is hydrophilic, which
means that it easily bonds with water by means of a hydrogen bond.
In this way, the PVP is easily dissolved in water to form the
lubricant (31) in the present instance.
[0096] The inner container (32) is formed by the inner layer (33),
which comprises polyethylene. The PVP based lubricant (31) does not
move through the polyethylene inner layer (33) under force of
osmosis and the inner container (32) therefore provides an
effective barrier to prevent loss of the lubricant (31) from the
prosthesis.
[0097] FIG. 6 shows the general construction of the layers of the
prosthesis, namely the outer layer (34) which forms the shell (35)
which contains the entire contents of the prosthesis. Below the
outer layer (34) is the inner layer (33) which is separated from
the outer layer (34) by a layer of lubricant (36), which is the
same as the lubricant (31) used between the cells (30). The cells
(30) within the PVP based lubricant (31) are located underneath the
inner layer (33).
[0098] FIG. 7 shows a third embodiment of a construction of inner
and outer containers for a prosthesis according to the invention,
which comprises an outer layer (37) similar to the outer layer (34)
of FIG. 6. Below this outer layer (37) there is an inner layer (38)
comprised of polyethylene which carries a layer of aluminium (39).
The aluminium layer (39) is adhered to the polyethylene inner layer
(38) by means of a vapour deposition process. Between the inner
layer 380 and the outer layer (37) there is a layer of lubricant
(40) which is comprised of a mixture of glycerine and water. Below
the inner layer (38) is shown the cells (41) within a lubricant
(42), which is also comprised of a mixture of water and
glycerine.
[0099] The laminate (43) shown in FIG. 7 has a total thickness of
about 48 micron, with the vapour deposited aluminium layer having a
thickness in the range of about 12 micron to 18 micron. The total
thickness of the laminate (43) may vary between about 20 micron and
about 70 micron.
[0100] The embodiments of the laminates in combination with the
respective lubricants shown in FIGS. 5 to 7 are effective in
enclosing the cells and lubricant. The laminates and lubricants may
be used in prostheses such as shown in FIG. 4, i.e. a single outer
container in the form of the silicone shell (21) and a single inner
container (22).
[0101] A third embodiment of a prosthesis (50) according to the
invention in shown in FIG. 8. In this embodiment the prosthesis
(50) includes an outer container in the form of a silicone shell
(51), an inner container (52) within which a plurality of small
sachets (53) are contained. The inner container (52) and sachets
(53) are manufactured from the laminates shown in any of FIGS. 5 to
7. Each of the sachets (53) contains a plurality of the
biocompatible synthetic cells (54). Each sachet (53) includes
lubricant (55) between the cells (54) and the inner container (52)
includes lubricant (56) within which the sachets (53) are located.
There is also lubricant (57) between the shell (51) and inner
container (52).
[0102] The inner containers (22, 52) show in FIGS. 4 and 8 have
surface areas which are greater than the surface area of their
respective outer containers or shells (2, 51). In the embodiments
shown in FIGS. 4 and 8 the respective surface areas of the inner
containers (22, 52) are greater than the respective maximum surface
area to which the respective outer containers or shells (2, 51) may
be stretched elastically. This means, that the inner containers
(22, 52) are large enough that any practical amount of elastic
deformation which the shells (2, 51) of the prostheses may
experience will not be so much that it will tear the inner
containers (22, 52). In other preferred embodiments, the surface of
the inner container should be at least twice as large as the
maximum surface area to which the outer container may be stretched
elastically.
[0103] A fourth embodiment of a prosthesis (60) according to the
invention is shown in FIG. 9. In this embodiment the prosthesis
(60) includes an outer container in the form of a silicone shell
(61), within which a plurality of small sachets (62) are contained.
This embodiment does not include a single large inner container,
but only a plurality of small sachets (62) within each of which
there are a plurality of biocompatible synthetic cells (63). There
is lubricant (64) within the shell (61) wherein the sachets (62)
are located and each sachet (62) includes lubricant (65) between
the cells (63).
[0104] The prosthesis shown in FIG. 4 may be manufactured with an
inner container from the laminate shown in FIG. 6, which is a
preferred embodiment of the invention. This embodiment includes an
inner container which comprises a polyvinyl pyrrolidone (PVP) based
lubricant and a plurality of the silicone cells, and having a
polyvinyl pyrrolidone (PVP) based lubricant between the inner and
outer containers.
[0105] In this embodiment the PVP based lubricant is mixed to
comprise about 15% PVP in a saline solution. The prosthesis is
manufactured in various sizes in three configurations, namely under
filled, regularly filled, and over filled.
[0106] In the under filled configuration the prosthesis is filled
to have a volume between 200 cm.sup.3 and 450 cm.sup.3 and to
include the respective weight of cells and weight of polyvinyl
pyrrolidone (PVP)/saline solution mixture in the inner container as
shown in the table:
TABLE-US-00004 Prosthesis PVP mixture volume (cm.sup.3) Cells (g)
(g) 200 82.352 82.352 225 92.646 92.646 250 102.94 102.94 275
113.234 113.234 300 123.528 123.528 325 133.822 133.822 350 144.116
144.116 375 154.41 154.41 400 164.704 164.704 425 174.998 174.998
450 185.292 185.292
[0107] In the regularly filled configuration, the prosthesis is
filled to have a volume between 200 cm.sup.3 and 450 cm.sup.3 and
to include the respective weight of cells and weight of polyvinyl
pyrrolidone (PVP)/saline solution mixture in the inner container as
shown in the table:
TABLE-US-00005 Prosthesis PVP mixture volume (cm.sup.3) Cells (g)
(g) 200 87.5 87.5 225 98.4375 98.4375 250 109.375 109.375 275
120.3125 120.3125 300 131.25 131.25 325 142.1875 142.1875 350
153.125 153.125 375 164.0625 164.0625 400 175 175 425 185.9375
185.9375 450 196.875 196.875
[0108] In the over filled configuration, the prosthesis is filled
to have a volume between 200 cm.sup.3 and 450 cm.sup.3 and to
include the respective weight of cells and weight of polyvinyl
pyrrolidone (PVP)/saline solution mixture in the inner container as
shown in the table:
TABLE-US-00006 Prosthesis PVP mixture volume (cm.sup.3) Cells (g)
(g) 200 95 95 225 106.875 106.875 250 118.75 118.75 275 130.625
130.625 300 142.5 142.5 325 154.375 154.375 350 166.25 166.25 375
178.125 178.125 400 190 190 425 201.875 201.875 450 213.75
213.75
[0109] Trials indicate that prostheses which are under filled
present with the best results, since it is almost impossible to
discern the prosthesis from natural breast tissue in such a
case.
[0110] FIGS. 10 to 14 show the steps of one method of filling a
prosthesis according to the invention.
[0111] As a first step, shown in FIG. 10, a inner container (70) is
formed from a laminate such as those shown in FIGS. 5 to 7. The
inner container (70) includes a filling aperture (71) through which
the correct weight of cells (72) and lubricant (73) is inserted.
For a specific size prosthesis, these weights will correspond with
the values given in the tables above, depending on whether the
prosthesis is to be under filled, regularly filled or over
filled.
[0112] Prior to inserting the filler material (74), i.e. the cells
(72) and lubricant (73), into the inner container (70), the air
inside the container (70) is evacuated using a vacuum pump. The
filler material (74) is then inserted into the inner container (72)
and it is sealed with a complimentary seal (81). The inner
container (70) is then inserted into a pre-manufactured silicone
shell (75). The filling aperture (76) of the shell (75) is closed
with a membrane (77), which is a silicone disc which has a
thickness typically of about 0.1 mm. Lubricant (78) is then
injected through the membrane (77) by means of a needle (not
shown), and the needle retracted. The membrane (77) is self
sealing. The filling aperture (75) is then closed with a plug (79),
which is a silicone disc with a thickness of about 0.9 mm. The plug
(79) and membrane (77) create a seal of about 1 mm in the filling
aperture. Both the membrane (77) and the plug (79) are secured to
the shell (76) by means of silicone glue.
[0113] In this way the prosthesis (80) is filled with the required
weight of cells (72) and lubricant (73, 78) and by using the vacuum
process no excess air is left inside the prosthesis (80).
[0114] Once the prosthesis (80) has been filled it is sealed into a
double layer package and the entire package is then subjected to
radiation for a predetermined time, typically about 8 hours, to
sterilize it. The package is only opened during the procedure to
implant the prosthesis, which ensures that the prosthesis (80)
remains sterile, at least until it is opened in the operating
theatre.
[0115] FIGS. 15 and 16 show a mould (82) used to manufacture the
biocompatible synthetic cells used in the prostheses. The mould
(82) comprises a set of two plates (83, 84) each of which includes
a plurality of cavities (85, 86) of which each corresponds to a
half-portion of a cell (87) formed therein. The plates (83, 84) may
be aligned and closed to form the complete cell negative cavities
(88) between them.
[0116] The process includes spraying the cavities (85, 86) on the
plates (83, 84) with sterilized liquid silicone to a overfill the
cavities (85, 86), aligning and closing the plates (83, 84). This
forces the liquid silicone in the half-portion cavities (85, 86) to
join to form a lenticular shaped silicone cell (87) between them.
To aid the joining process heat may also be applied to the plates
(83, 84) to the circular areas surrounding the cavities (85,
86).
[0117] After a predetermined time the liquid silicone sets and the
plates (83, 84) are removed from each other to reveal the cells
(87) formed between them.
[0118] FIG. 16 shows a closer view of one of the cavities (85, 86)
used to form the cells (87). The one plate cavity (85) includes an
annular trimming formation (88) around the periphery of the cavity
(85). When the plates (83, 84) are pressed close the trimming
formation (88) bears against the flat surface (89) surrounding the
opposing cavity (86) of the other plate (84) and trims the edge of
the cell (87) where its two halves are joined.
[0119] It will be appreciated that the embodiments described above
are not exhaustive of the invention and it is possible to alter
some aspects of the prostheses without departing from the scope of
the invention.
[0120] It is possible to use different sized or shaped
biocompatible cells, for example ovoid or bean shaped cells.
[0121] It is also possible to use weights of cells and lubricant
within the ranges of values shown in the tables.
[0122] It is further possible to include a tracer in the form of a
particle in each cell to enhance the traceability of the cells.
Titanium may for example be used to manufacture the particles. The
particles will be inserted into the cells before forming them and
will therefore form an inseparable part of each cell. In case of
rupture of the shell and escape of some of the cells, a surgeon may
use external diagnostic equipment or techniques including MRI,
X-ray, or ultrasound to locate the exact position of each cell.
[0123] It is also possible to include a data transmission device,
typically in the form of a transponder or Radio Frequency
Identification tag, in the prosthesis. This RFID will be loaded
with information relating to the prosthesis, including the size of
the prosthesis, date of manufacture, and date of implanting into
the patient. It may also be used to store the name of the patient,
medical fund details of the patient, and emergency contact details
relating to the patient. It is envisaged that this will allow a
surgeon to establish the exact nature of the prosthesis without any
invasive techniques. In the event of failure of the prosthesis,
such as in a motor vehicle accident, where the patient may not be
in position to convey critical information about the prosthesis an
RFID scanner may be used to obtain information form the patient and
perform any necessary procedure. This will also be helpful where a
patient wishes to have a set of prostheses changed, for example for
a larger set. In most instances, patients do not remember the
details such as type, manufacturer and size of prosthesis. A
surgeon then needs to have a range of prostheses on hand during the
procedure to replace the prosthesis. If the surgeon knew the type
of the original set of prostheses and their sizes, it becomes much
easier and quicker to replace them. It is envisaged that the RFID
tag will secured into one of the cells, or inside the shell. The
surgeon will use a commercially available RFID scanner to energize
the RFID tag, which triggers it to transmit the data stored on it.
This data carrying signal is then received by the scanner and
interpreted by custom software operated on the scanner. The
information contained in the RFID tag is then displayed on a
display screen of the scanner, or printed out.
[0124] In the same manner it will be possible to write information
to the RFID tag. In this way the data stored on it may be updated,
for example with the name of the patient, the date on which the
prosthesis was implanted, the medical fund details of the patient
and so forth.
[0125] It is also possible that the RFID tag may simply transmit a
unique identification number and that the relevant details of the
patient may be obtained from a secure computer server available on
a network, typically the Internet. A physician will then log onto
the secure server, enter the unique identification number obtained
with the scanner and obtain information about the patient and the
prosthesis from the server.
* * * * *