U.S. patent application number 17/014988 was filed with the patent office on 2020-12-24 for dual plane breast implant.
The applicant listed for this patent is Allergan, Inc.. Invention is credited to David J. Schuessler, Dennis E. Van Epps.
Application Number | 20200397554 17/014988 |
Document ID | / |
Family ID | 1000005077014 |
Filed Date | 2020-12-24 |
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United States Patent
Application |
20200397554 |
Kind Code |
A1 |
Van Epps; Dennis E. ; et
al. |
December 24, 2020 |
DUAL PLANE BREAST IMPLANT
Abstract
A soft breast prosthesis is provided, the prosthesis having a
surface configuration advantageous for dual plane placement of the
prosthesis in a breast.
Inventors: |
Van Epps; Dennis E.;
(Goleta, CA) ; Schuessler; David J.; (Santa Ana,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Allergan, Inc. |
Irvine |
CA |
US |
|
|
Family ID: |
1000005077014 |
Appl. No.: |
17/014988 |
Filed: |
September 8, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15819544 |
Nov 21, 2017 |
10765501 |
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17014988 |
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14728249 |
Jun 2, 2015 |
9848972 |
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15819544 |
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13908232 |
Jun 3, 2013 |
9050184 |
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14728249 |
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12540317 |
Aug 12, 2009 |
8506627 |
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13908232 |
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61655937 |
Jun 5, 2012 |
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61088418 |
Aug 13, 2008 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2250/0026 20130101;
A61F 2002/30322 20130101; A61F 2250/0051 20130101; A61F 2/12
20130101; A61F 2002/0086 20130101; A61F 2/0077 20130101; A61F
2002/0081 20130101 |
International
Class: |
A61F 2/00 20060101
A61F002/00; A61F 2/12 20060101 A61F002/12 |
Claims
1. A monolithic breast implant prosthesis comprising an implantable
member including an exterior having a posterior surface, an
anterior surface, an upper portion, and a lower portion, the
implantable member having a lower pole region with a textured outer
surface and an upper pole region with a smooth outer surface, the
lower pole region having an upper edge extending at an angle
relative to a vertical axis of the implant, the lower pole region
extending along only the lower portion of the exterior, the upper
pole region extending along the upper portion of the exterior along
at least one of the posterior surface or the anterior surface of
the exterior, the smooth outer surface having a relatively less
textured surface than the textured outer surface.
2. The prosthesis of claim 1, wherein the textured outer surface of
the lower pole region encompasses between about 20% and about 80%
of the exterior.
3. The prosthesis of claim 1, wherein the textured outer surface of
the lower pole region extends along the posterior surface.
4. The prosthesis of claim 1, wherein the textured outer surface of
the lower pole region extends along the anterior surface.
5. The prosthesis of claim 1, wherein the smooth outer surface of
the upper pole region extends along the posterior surface.
6. The prosthesis of claim 1, wherein the textured outer surface of
the lower pole region outer surface comprises a plurality of
textured bands.
7. The prosthesis of claim 1, wherein the textured outer surface of
the lower pole region outer surface comprises a plurality of
textured bands extending along an anterior.
8. A monolithic breast implant prosthesis comprising an implantable
member including an exterior having a posterior surface, an
anterior surface, an upper portion, and a lower portion, the
implantable member having a lower pole region with a textured outer
surface, an upper pole region with a smooth outer surface, and a
boundary extending between the textured outer surface and the
smooth outer surface at an angle relative to a vertical axis of the
implant, the smooth outer surface extending along the upper portion
of the exterior along at least one of the posterior surface or the
anterior surface of the exterior.
9. The prosthesis of claim 8, wherein the textured outer surface of
the lower pole region extends along the posterior surface.
10. The prosthesis of claim 8, wherein the textured outer surface
of the lower pole region extends along the anterior surface.
11. The prosthesis of claim 8, wherein the smooth outer surface of
the upper pole region extends along the posterior surface.
12. The prosthesis of claim 8, wherein the textured outer surface
of the lower pole region outer surface comprises a plurality of
textured bands.
13. A method of augmenting or reconstructing a human breast
comprising: implanting in a breast a breast implant including an
exterior having a posterior surface, an anterior surface, an upper
portion, and a lower portion, the breast implant having (i) a lower
pole region with a textured outer surface and (i) an upper pole
region with a smooth outer surface, the lower pole region having an
upper edge extending at an angle relative to a vertical axis of the
implant, the textured outer surface of the lower pole region
extending along only the lower portion of the exterior, the smooth
outer surface of the upper pole region extending along the upper
portion of the exterior along at least one of the posterior surface
or the anterior surface of the exterior, the breast implant being
positioned such that the textured outer surface of the lower pole
region is placed subglandularly and the smooth outer surface of the
upper pole region is placed submuscularly.
14. The method of claim 13, wherein the textured outer surface of
the lower pole region encompasses between about 20% and about 80%
of the exterior.
15. The method of claim 13, wherein the textured outer surface of
the lower pole region encompasses between about 30% and about 70%
of the exterior.
16. The method of claim 13, wherein the textured outer surface of
the lower pole region encompasses between about 40% and about 60%
of the exterior.
17. The method of claim 13, wherein the textured outer surface of
the lower pole region comprises a plurality of textured bands.
18. The method of claim 13, wherein the textured outer surface of
the lower pole region comprises a plurality of textured bands
encompassing between about 20% and about 80% of the exterior.
19. The method of claim 13, wherein the textured outer surface of
the lower pole region comprises a plurality of textured bands
encompassing between about 30% and about 70% of the exterior.
20. The method of claim 13, wherein the textured outer surface of
the lower pole region comprises a plurality of textured bands
encompassing between about 40% and about 60% of the exterior.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/819,544, filed Nov. 21, 2017, which is a
continuation of U.S. patent application Ser. No. 14/728,249 filed
on Jun. 2, 2015, now U.S. Pat. No. 9,848,972, which is a
continuation of U.S. patent application Ser. No. 13/908,232 filed
Jun. 3, 2013, now U.S. Pat. No. 9,050,184, which claims priority to
U.S. Provisional Patent Application No. 61/655,937, filed Jun. 5,
2012, and which U.S. patent application Ser. No. 13/908,232 is a
continuation-in-part of U.S. patent application Ser. No.
12/540,317, filed Aug. 12, 2009, now U.S. Pat. No. 8,506,627, which
claims priority to U.S. Provisional Patent Application No.
61/088,418, filed Aug. 13, 2008, the entire contents of each of
these documents being incorporated herein by this reference.
FIELD OF THE INVENTION
[0002] The present invention relates to soft prosthetic implants
and, more particularly, to textured exterior surfaces of such
implants, for instance, breast implants.
BACKGROUND OF THE INVENTION
[0003] Implantable prostheses are commonly used to replace or
augment body tissue. In the case of breast cancer, it is sometimes
necessary to remove some or all of the mammary gland and
surrounding tissue, which creates a void that can be filled with an
implantable prosthesis. The implant serves to support surrounding
tissue and to maintain the appearance of the body. The restoration
of the normal appearance of the body has a beneficial psychological
effect on post-operative patients, eliminating much of the shock
and depression that often follows extensive surgical procedures.
Implantable prostheses are also used more generally for restoring
the normal appearance of soft tissue in various areas of the body,
such as the buttocks, chin, calf, etc.
[0004] Soft implantable prostheses typically include a relatively
thin and flexible envelope or shell made of vulcanized (cured)
silicone elastomer. The shell is filled either with a silicone gel
or with a normal saline solution. The filling of the shell takes
place before or after the shell is inserted through an incision in
the patient.
[0005] In the United States, women can generally choose between two
different types of breast implant shell surfaces: a smooth surface
and a textured surface. The surgeon generally recommends the type
of surface based on his or her technique and the need of the
individual patient.
[0006] Breast implants may be placed in the breast in one of
several different positions, depending on desired outcome, and/or
patient and surgeon preference.
[0007] In subglandular placement, the breast implant is placed in a
surgically formed pocket directly between the glandular breast
tissue and the pectoralis major muscle. This placement most
approximates the plane of normal breast tissue. In addition, this
placement may offer shorter surgery, less pain and discomfort and
perhaps a faster recovery. On the downside, subglandular placement
may result in a more palpable implant, a higher chance of visible
rippling or folding of the implant, and higher risk of capsular
contracture.
[0008] In submuscular placement, the breast implant is placed
beneath the pectoralis major muscle. Thus, the implant is further
away from the skin surface and may be less visible or less
palpable. This placement may appear more "natural" because the
implant is further away from the skin. It may require a longer
surgery and recovery period, but is believed to results in a
reduced chance for capsular contracture. In breast reconstruction
patients where natural breast tissue may be substantially or
entirely absent, this placement approach effects maximal coverage
of the implant.
[0009] Dual plane breast implant placement is a combination
approach in which the implant is placed beneath the pectoralis
major muscle, after the surgeon releases the inferior muscular
attachments. As a result, the upper portion of the implant is
partially beneath the pectoralis major muscle, while the lower
portion of the implant is positioned in the subglandular plane.
This implantation technique may achieve improved coverage of the
upper portion of the implant and allow filling of minor laxity of
the lower breast.
[0010] Despite many advances in the development of safe and
comfortable breast prostheses, there remains room for
improvement.
SUMMARY OF THE INVENTION
[0011] The present invention provides a prosthesis suitable for
implantation in a human being, for example, a breast implant
suitable for use in reconstruction or augmentation of the human
breast. The prosthesis generally comprises an implantable member,
for example, an elastomeric shell that is filled or is fillable
with a liquid or gel. The implantable member has an exterior
surface including one or more fixation regions defined thereon and
configured, positioned or structured to provide enhanced or
controlled tissue ingrowth or adhesion.
[0012] In accordance with one aspect of the invention, the fixation
surfaces are discrete, generally elongated surface portions
extending across an anterior face or a posterior face of the
implant. These fixation surfaces, sometimes herein referred to as
"fixation regions", are generally defined by a texture, roughness
or sheen that is different from a texture, roughness or sheen of
adjacent surface portions of the implant.
[0013] In some embodiments, the fixation regions have an increased
or enhanced texture relative to the balance of the anterior face or
posterior face of the implant. In other words, the balance of the
exterior surface may be relatively less textured than the fixation
regions. In some embodiments, the fixation regions are textured and
adjacent surfaces, for example, the surface or surfaces that are
not defined by the fixation regions, are substantially less
textured, or are relatively smooth.
[0014] The prosthesis may be structured to encourage enhanced
tissue ingrowth or adhesion at the fixation regions, relative to an
otherwise identical surface without such texture, roughness or
sheen.
[0015] In one aspect of the invention, the fixation regions are
positioned and/or configured such that the prosthesis, after
implantation in the body, moves more naturally with the human body,
for example, in relative unity with the muscles of the body. It is
contemplated that because the implant moves more naturally with the
human body, the implant may be less prone to wear resulting from
material stresses relative to conventional implants, for example,
implants without such fixation regions. Furthermore, it is
contemplated that the present implants will be more comfortable to
the patient in that they will move more naturally with the
body.
[0016] In a more specific aspect of the invention, the fixation
regions may be located at specific regions on an anterior face of
the shell, that is, a face of the shell which faces the front of
the human body when the implant has been appropriately implanted in
the human body. Alternatively or additionally, one or more discrete
fixation surface may be provided on a periphery of the shell (e.g.
circumferentially) and/or on the posterior face of the shell, that
is, the face of the shell that faces the back of the human body
when the implant has been implanted in the human body.
[0017] In an even more specific aspect of the invention, the
fixation regions comprise at least one elongated region located on
the anterior face of the shell. The at least one elongated region
may be, for example, a band-shaped region or alternatively, a
plurality of band shaped regions having enhanced texture, roughness
or sheen.
[0018] The elongated fixation regions may be positioned to align
with one of the pectoralis major muscle groups or pectoralis minor
muscle groups of the human body when the implant is implanted in
the body. For example, in one embodiment of the invention, the at
least one elongated region comprises a diagonally positioned band
shaped region intended to align with the pectoralis major muscle
group when the implant has been implanted in the body. In another
embodiment, the at least one fixation region comprises a plurality
of elongated regions in a radiating configuration generally copying
the positioning of the pectoralis minor muscle group wherein the
implant has been implanted in the body.
[0019] In another broad aspect of the invention, the prosthesis
comprises a breast implant having a shell including a fixation
region having a first texture and a balance of the shell surface
having a second texture that is different from the first texture.
In other words, in some embodiments of the invention, the entire,
or substantially entire, exterior of the breast implant shell is a
textured surface with specific regions thereof having a greater
degree of texturing relative to the remaining portions of the
textured surface.
[0020] It is contemplated that such different texturing will
stimulate or encourage different degrees of tissue ingrowth or
adhesion at the different fixation regions. For example, in one
embodiment, the first fixation region is located on a posterior
face of the implant and the second fixation region is located on an
anterior face of the implant. The first fixation region may be
defined by a texture that is more conducive to tissue interaction
and adhesion whereas the second fixation region may be defined by a
texture that is relatively less conducive to tissue interaction and
adhesion.
[0021] In one embodiment, a breast prosthesis is provided having a
relatively more significant texture defining the anterior surface
of the implant, and a less textured or smooth surface defining the
posterior surface of the implant.
[0022] In yet another aspect of the invention, the prosthesis
comprises a shell having an exterior structured to contact tissue,
the shell including a first fixation surface having a first open
cell structure, and a second fixation surface having a second open
cell structure different than said first open cell structure. In
addition, the first fixation surface and the second fixation
surface are positioned to encourage respectively different degrees
of tissue ingrowth or tissue adhesion by the body at a body-shell
interface.
[0023] For example, the first open cell structure comprises
relatively large open cells and the second open cell structure
comprises relatively smaller open cells. Alternatively or
additionally, the first open cell structure may comprise a first
distribution of cells and the second open cell structure comprises
a second distribution of cells wherein the first distribution of
cells is relatively more dense than the second distribution of
cells.
[0024] In yet another specific aspect of the invention, the first
open cell structure comprises relatively large rounded open cells
and the second open cell structure comprises relatively small
rounded open cells. Alternatively, the first open cell structure
comprises relatively rounded open cells and the second open cell
structure comprises relatively angular open cells.
[0025] Advantageously, in accordance with certain embodiments, the
first and second fixation surfaces are positioned and structured to
be at least somewhat effective to disrupt or disorient capsular
tissue formation about the prosthesis after the prosthesis has been
implanted in the body.
[0026] The present invention further provides a breast prosthesis
shell for implantation in a human being, the shell manufactured by
the steps of providing a shell precursor; applying a layer of
silicone elastomer to the shell precursor, applying solid particles
of a first configuration to a portion of the layer of silicone
elastomer and applying solid particles of a second configuration to
another portion of the layer of silicone elastomer before the layer
is fully cured. After the layer including the solid particles
embedded therein is cured, the solid particles are then dissolved,
for example, by means of a solvent that does not dissolve the
silicone elastomer to any appreciable extent. The resulting
elastomer shell includes a first open cell texture region formed by
said application of the solid particles of the first configuration,
and a second open cell texture region formed by said application of
the solid particles of the second configuration.
[0027] In yet another aspect of the invention, a method of
augmenting or reconstructing a breast of a human being is provided.
The method generally comprises providing an implantable member
including at least one elongated fixation region as described
elsewhere herein and implanting the implantable member into a
breast of a human being such that the fixation region generally
aligns with one of the pectoralis major muscle group and the
pectoralis minor muscle group. The method may further comprise
filling the implantable member with a liquid or gel prior to or
after the implanting step.
[0028] In another aspect of the invention, a dual plane breast
prosthesis is provided, the prosthesis comprising an implantable
member including an exterior defined by a textured lower region or
lower pole, configured for subglandular placement, and an upper
region or upper pole, that is smooth or differently textured and
which is configured for submuscular placement. For example, the
first texture and the second texture are structured such that first
texture encourages greater tissue ingrowth than the second
texture.
[0029] In this embodiment, the implant may be surgically positioned
as a dual plane breast implant, in other words, the implant may be
placed in the breast such that an upper portion of the implant is
beneath the pectoralis major muscle, while the lower portion of the
implant is in the subglandular plane.
[0030] For example, the textured lower region may be a relatively
more aggressive textured surface that encourages adhesion and
tissue ingrowth, for example, to glandular and fatty tissue, while
the upper region may be a less aggressive textured surface, or even
a smooth, untextured surface, to allow for more free muscle
movement and reduced tissue adhesion.
[0031] The textured lower region may encompass between about 20%
and about 80% of the surface area of the exterior of the
implantable member, or between about 30% and about 70% of the
surface area of the exterior of the implantable member, or between
about 40% and about 60% of the surface area of the exterior of the
implantable member, or about 50% of the surface area of the
exterior of the implantable member.
[0032] For example, the first texture may comprise an open cell
textured surface and the second texture may be a closed cell
textured surface. Alternatively, the first texture may comprise a
closed cell textured surface and the second texture may be a
relatively smooth, untextured surface. Other variations are
contemplated.
[0033] The present invention further provides methods of augmenting
or reconstructing a human breast using a dual plane approach
wherein the method comprises implanting in a breast, an implantable
member including an exterior defined by a lower surface region
encompassing a lower portion of the implantable member and an upper
surface region encompassing an upper portion of the implantable
member, and wherein the lower surface region is defined by a first
textured surface and the upper surface region is defined by one of
a smooth surface or a second textured surface different from the
first textured surface, and further the implant being placed in the
breast such that the upper surface region is positioned between
beneath the pectoralis major muscle and the lower region is
positioned anteriorly of the pectoralis major muscle.
[0034] A further understanding of the nature and advantages of the
present invention are set forth in the following description and
claims, particularly when considered in conjunction with the
accompanying drawings in which like parts bear like reference
numerals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Features and advantages of the present invention will become
appreciated as the same become better understood with reference to
the specification, claims, and appended drawings wherein:
[0036] FIGS. 1A-1B are a front view and a side elevational view,
respectively, of an exemplary round breast implant of the present
invention;
[0037] FIGS. 2A-2B are a front view and side elevational view,
respectively, of an exemplary shaped breast implant of the present
invention;
[0038] FIGS. 3A and 3B are schematic views of a woman's upper torso
showing, alignment of the pectoralis major muscle group and the
pectoralis minor muscle group, respectively;
[0039] FIGS. 4A, 4B and 4C are vertical sectional views through a
woman's breast and adjacent chest anatomy showing, respectively:
subglandular, submuscular and dual plane placement of a breast
implant of the present invention;
[0040] FIGS. 5A-5B are front and side elevational views of an
exemplary round breast implant of the present invention having a
generally elongated or band-shaped fixation surface;
[0041] FIGS. 6A-6B are front and side elevational views of an
exemplary shaped breast implant of the present invention having a
generally elongated or band-shaped fixation surface;
[0042] FIG. 7 is a front elevational view of another breast implant
in accordance with the invention including a first fixation region
having a first texture and a second fixation region having a second
texture different from the first texture.
[0043] FIGS. 8A and 8B are front and rear elevational views of an
exemplary round breast implant of the present invention having a
front texture and a rear texture that are different from one
another.
[0044] FIG. 9A shows a simplified representation of a dual plane
breast implant in accordance with one embodiment of the invention,
the implant being shown with an upper region located partially
under the pectoralis major muscle and a lower region located in the
subglandular plane.
[0045] FIGS. 9B and 9C show a front view and side view,
respectively, of a dual plane breast implant in accordance with an
embodiment of the invention.
[0046] FIGS. 10A and 10B show another embodiment of the invention
wherein the implant includes a more textured anterior surface and a
less textured or smooth posterior surface.
DETAILED DESCRIPTION
[0047] The present invention provides a saline- or gel-filled soft
implant shell, preferably a silicone elastomer shell, with a
fixation surface over an exterior portion. The primary application
for such soft implants is to reconstruct or augment the female
breast. Other potential applications are implants for the buttocks,
testes, or calf, among other areas.
[0048] The terms "fixation surface" or "fixation region", as used
herein, generally refer to a region or portion of an exterior
surface of an implant which is positioned, structured or adapted to
encourage tissue ingrowth or adhesion at a body/implant interface.
For example, a fixation region may be a texture, roughness or sheen
that is distinct from, for example, more pronounced than, adjacent
surfaces of the implant which do not encourage tissue ingrowth of
adhesion to the same degree as the fixation region. For example,
other regions or surfaces of the implant exterior may be relatively
smooth or less textured relative to the fixation regions.
[0049] Such a fixation region may be formed by any suitable means,
for example, but not limited to, a salt removal process such as
described in U.S. Pat. No. 5,007,929, with appropriate changes
being made. Alternatively, the fixation surfaces may be formed by
separate textured elements such as textured patches or films
adhered to the outside of an otherwise "smooth" or less textured
implant. Still, another method for forming the discrete fixation
regions may be by using a relatively roughened surface portion of a
mold used to form the implant. Another method for forming the
present fixation regions includes texturing the exterior of the
implant after formation. The present invention should not be
considered limited to any particular type of texturing or fixation
surface, though there might be certain advantages with one or more
of these techniques.
[0050] Turning now to the Figures, FIGS. 1A and 1B are front and
side elevational views of an exemplary round breast implant 20 of
the present invention. Generally, the implant 20 comprises an
exterior surface defined by a relatively smooth anterior face 21, a
textured posterior face 22 and a textured peripheral region 24
located between the anterior face 21 and the posterior face 22. The
relatively smooth anterior face may be a relatively less textured
surface (relative to texture of posterior face 22), such as, for
example, a fine textured surface or even a matte finish. In some
embodiments, the implant 20 has a relatively smooth posterior face,
a textured anterior face and a textured or smooth peripheral
region. The fixation surfaces 22, 24 themselves may have differing
degrees of texturing. The diameter D and front-to-back thickness T
of the implant are shown and vary depending on the patient's chest
size and aesthetic considerations.
[0051] In the shown embodiment, the rear fixation surface 22
extends to the apex 26 or generatrix of the convex outer periphery
of the implant 20. The peripheral fixation surface 24 continues
forward a short distance S onto the anterior or front surface 21.
In some embodiments, the distance S is between about 10% and about
30% of the thickness T. In some embodiments, the peripheral
fixation surface 24 extends substantially entirely around the
periphery of the implant 20, such that the implant 20 is
axi-symmetric. In other embodiments, the peripheral fixation
surface 24 may be abbreviated so as to extend around only a portion
of the periphery of the implant, such as the inferior or superior
half, or the peripheral fixation surface may be broken up into
spaced apart segments. In some embodiments, the peripheral fixation
surface 24 comprises substantially evenly spaced segments resulting
in alternating smooth and textured areas.
[0052] FIGS. 2A-2B illustrate an exemplary shaped breast implant 30
of the present invention having an inferior frontal lobe 32
simulating a natural breast. Like implant 20, implant 30 includes a
rear fixation surface 34 and a peripheral fixation surface 36. The
width W, height H, and front-to-back thickness T of the implant are
shown. If the front projection is round, then W=H, otherwise W may
be greater than or less than H. When provided with a natural shape,
the implant 30 has a proper orientation, namely with the inferior
lobe 32 at the lower center. Accordingly, the peripheral fixation
surface 36 may extend completely around the periphery of the
implant, or may be formed in discrete areas and be oriented
relative to the natural shape of the implant. For example, the
peripheral fixation surface 36 may be formed only around the
inferior or lower half of the implant, or may be formed only on the
sides.
[0053] FIG. 3A illustrates a woman's upper torso schematically
showing on one side placement and alignment of the pectoralis major
muscle group, while FIG. 3B illustrates the placement and alignment
of the pectoralis minor muscle group. These two muscle groups
overlap one another and extend generally from the shoulder or
collarbone region to the rib cage underneath the breast. One aspect
of the present invention is to provide an implant including
fixation surfaces such as described elsewhere herein, which are
substantially aligned with these muscle groups when the implant is
placed in the body.
[0054] While not wishing to be bound by any specific theory of
operation, the regions or lines of contact of the implant with the
primary chest muscles experience greater movement than other areas
of the implant not interfacing the muscles. It is believed by the
present inventors that by providing a fixation region of the
implant that is substantially coincident with or in substantial
alignment with one or more of these muscle groups is more likely to
remain secured and move with the muscle. In addition, it is
contemplated that such discrete fixation regions may provide the
benefit of disrupting capsule formation and/or reducing the
potential for capsular contraction.
[0055] FIG. 4A is a vertical sectional view through a woman's
breast and adjacent chest anatomy showing a subglandular placement
of a breast implant 40. The implant 40 is positioned over the top
of the pectoralis major muscle group 42, which in turn overlays the
pectoralis minor muscle group 44. The chest wall 48 showing a
plurality of ribs 50 is also indicated underneath the pectoralis
minor muscle 44.
[0056] FIG. 4B shows a complete submuscular placement of an
implant. In this case, the upper pole, for example, about 2/3 of
the upper surface of the breast implant is covered by the
pectoralis muscle, and the lower pole, for example, about 1/3 of
the lower portion of the breast implant, is covered by the muscle
fascia.
[0057] FIG. 4C shows a dual plane placement of the implant 40. With
a dual plane placement, an upper pole of the implant is partially
beneath the pectoralis major muscle, while a lower pole of the
implant is located in the subglandular plane. This may be
accomplished by creating a pocket beneath the pectoralis major
muscle with release of the inferior muscular attachments, with or
without partial dissection of the subglandular plane.
[0058] Each of these implant placements are utilized primarily
depending on the surgeon's clinical determination, sometimes
influenced by a dialogue between patient and the surgeon and
desired outcome. Depending on the implant placements, the implant
40 may be in contact with one or both muscle groups. In some
embodiments of the invention, the implant includes substantially
elongated fixation regions as described and shown herein, and said
fixation regions being in substantial alignment with the
appropriate muscle group which interface the implant when the
implant is placed in the body.
[0059] For example, FIGS. 5A-5B are front and side elevational
views of an exemplary round breast implant 60 of the present
invention having a posterior face 62, a peripheral region 64, and
an anterior face including an elongated or band-shaped fixation
region 66. The band-shaped fixation region 66 extends generally
along a diagonal angle and commences at the front border of the
peripheral fixation surface 64. The illustrated embodiment, the
fixation region 66 has a substantially constant width W as seen
from the front in FIG. 5A. In one embodiment, the width W is
between about 1 mm to about 20 mm, for example, between about 2 mm
to about 15 mm. Alternatively, although not shown, the fixation
region 66 may have a configuration that is other than a constant
width.
[0060] In one embodiment, the band-shaped fixation surface 66 is
generally oriented or aligned with either the pectoralis major
muscle group or pectoralis minor muscle group when the implant is
implanted in the breast. For instance, if the implant 60 is
destined for a submuscular placement such as in FIG. 4B, the
fixation surface 66 may be oriented to be generally aligned with
the pectoralis major muscle group, as seen in FIG. 3A.
Alternatively, the angle at which the insertion surface 66 is
oriented may be an approximation of the average angle of the
pectoralis major and pectoralis minor muscle groups. In this way,
the implant 60 has a fixation surface 66 to encourage tissue
ingrowth or adhesion along the major stress lines of the implant.
Preferably, the fixation surface 66 is angled between about
30-60.degree. with respect to a vertical plane through the implant
60. Of course, if the implant 60 is round as shown, the fixation
surface 66 itself defines the orientation thereof. In one
embodiment, the band-shaped fixation surface 66 is centered about
the center of the implant 60, therefore creating two symmetric
orientations about 180.degree. apart. This arrangement facilitates
implant by providing two possible orientations for the surgeon.
[0061] The band-shaped fixation region 66 may extend substantially
across the anterior face of the implant and may be defined by a
texture that is different from a balance of the anterior face. The
fixation region 66 may also have a different texture, for example,
a more pronounced or more aggressive texture, than the rear
fixation surface 62 or peripheral surface 64.
[0062] FIGS. 6A-6B illustrate another exemplary shaped breast
implant 70 of the present invention. The implant 70 again features
a rear fixation surface 72, a peripheral fixation surface 74, and a
plurality of separate band-shaped fixation surfaces 76a, 76b, and
76c. These discrete fixation surfaces 76a, 76b, 76c are positioned
or configured to align with one or more of the muscle groups
described above. For example, the three fixation surfaces 76a, 76b,
76c may be generally oriented relative to the fan-shaped pectoralis
minor muscle group. Because the shaped implant 70 is
orientation-specific, proper placement of the implant orients the
fixation surfaces 76a, 76b, and 76c with the particular muscle
group. As mentioned above, the various fixation surfaces 72, 74,
76a, 76b, and 76c may be formed with a similar level of roughness,
or some may be less textured, such as with a matte finish. For
instance, the rear and peripheral fixation surfaces 72, 74 may have
a fine, matte finish, while the frontal fixation surfaces 76a, 76b,
76c are more densely textured. The present invention contemplates
all permutations of texturing choices.
[0063] In cross-section, the textured implant shells of the present
invention may be single- or multi-layered. The overall thickness of
the textured implant shell wall may be somewhat greater than a
similar smooth-walled shell because of the extra layers of
texture.
[0064] Turning now to FIG. 7, an anterior (front) view of another
breast implant of the present invention is shown generally at 110.
The implant 110 includes a shell 112 having an exterior surface
including a first fixation region 114 having a first texture 116
and a second fixation region 118 having a second texture 122 that
is different from the first texture 116. In the shown embodiment,
the first texture 116 is a more "aggressive" texture than the
second texture 122. The first texture 116 is structured to
encourage a greater degree of tissue interaction than the second
texture 122.
[0065] In lieu of the second texture 122, it is contemplated that
the second fixation region 118, and perhaps the entire balance of
the exterior of the shell 112, may be a low sheen surface, for
example, a matte finish.
[0066] Turning now to FIGS. 8A and 8B, anterior (front) and
posterior (rear) views, respectively, of another breast implant in
accordance with the invention are shown generally at 210. The
implant 210 includes a shell 212 having an anterior face 212a and a
posterior face 212b, and including a first fixation region 214
having a first texture 216 and a second fixation region 218 having
a second texture 222 that is different from the first texture 216.
In the shown embodiment, the first texture 216 may encompass the
entire, or substantially entire, anterior face 212a of the implant
210. The first texture 216 is defined by a first distribution of
pores, crevices or caverns that is relatively less dense than that
of the second texture 222. The second texture 222, which may
encompass the entire, or substantially entire, posterior face 221b
of the implant 210, may be structured to encourage a greater degree
of tissue interaction and adhesion than that of the first texture
216.
[0067] The shells 112 and 212 may be manufactured by a method of
the invention comprising the steps of providing a shell precursor;
applying a layer of silicone elastomer to the shell precursor,
applying solid particles of a first configuration to a portion of
the layer of silicone elastomer and applying solid particles of a
second configuration to another portion of the layer of silicone
elastomer before the layer is fully cured. After the layer
including the solid particles embedded therein is cured, the solid
particles are then dissolved, for example, by means of a solvent
that does not dissolve the silicone elastomer to any appreciable
extent. The resulting elastomer shell includes a first open cell
texture region formed by said application of the solid particles of
the first configuration, and a second open cell texture region
formed by said application of the solid particles of the second
configuration.
[0068] One process for forming flexible implant shells for
implantable prostheses involves dipping a suitably shaped mandrel
into a silicone elastomer dispersion. Many such dispersions are
used in the field. Basically they contain a silicone elastomer and
a solvent. The silicone elastomer is typically
polydimethylsiloxane, polydiphenyl-siloxane or some combination of
these two. Typical solvents include xylene or
1,1,1-trichloroethane. Different manufacturers vary the type and
amount of the ingredients in the dispersion, the viscosity of the
dispersion and the solid content of the dispersion. Nonetheless,
the present invention is expected to be adaptable to have utility
with a wide variety of silicone rubber dispersions.
[0069] The mandrel is withdrawn from the dispersion and the excess
silicone elastomer dispersion is allowed to drain from the mandrel.
After the excess dispersion has drained from the mandrel at least a
portion of the solvent is allowed to volatilize or evaporate.
Normally this is accomplished by flowing air over the coated
mandrel at a controlled temperature and humidity. Different
manufacturers use various quantities, velocities or directions of
air flow and set the temperature and humidity of the air at
different values. However, the desired result, driving off the
solvent, remains the same.
[0070] It is also common for prostheses manufacturers to repeat
this dip and volatilize procedure a number of times so that a
number of layers are built up on the mandrel to reach a desired
shell thickness. A layered structure like most current silicone
elastomer shells can be made by sequentially dipping the mandrel in
different dispersions. Alternatively, the steps may be repeated in
a single dispersion so that the finished product is a single
homogenous material or layer. That is, the dipping process may be
done in multiple stages or steps, each step adding more material,
yet the finished product exhibits no distinct layers and the entire
shell wall is homogenous or uniform in composition.
[0071] An exemplary process for forming the fixation surfaces on
either a multi-layered shell or a single-layered shell will now be
described. After the mandrel is raised out of the dispersion with
what is to be the final layer adhering thereto, this layer is
allowed to stabilize. That is, it is held until the final coating
no longer flows freely. This occurs as some of the solvent
evaporates from the final coating, raising its viscosity.
[0072] Again, it should be understood that alternative methods are
contemplated for forming the flexible shell prior to the texturing
process. The dip molding process advantageously results in the
flexible shell pre-mounted on a dipping mandrel, which can then be
used for the texturing process. However, if the flexible shell is
made by another technique, such as by rotational molding, it can
subsequently be mounted on a dipping mandrel and the process
continued in the same manner.
[0073] Once the flexible shell has been stabilized and mounted on
the mandrel, any loose fibers or particles are removed from the
exterior of the shell, for example, with an anti-static air gun. A
tack coat layer is then applied. The tack coat layer may be sprayed
on, but is desirably applied by dipping the flexible shell on the
mandrel into a tack coat dispersion. The operator immerses the
flexible shell into the dispersion and returns the mandrel to a
rack for stabilization. The time required for stabilization
typically varies between 5-20 minutes. A suitable tack coat layer
is desirably made using the same material employed in the base
layers.
[0074] At this point, granulated solid particles, for example,
dissolvable or leachable particles, are applied over that portion
of the exterior surface that will end up as the fixation surface.
The solid particles may be applied manually by sprinkling them over
the surface while the mandrel is manipulated, or a machine
operating like a bead blaster or sand blaster could be used to
deliver a steady stream of solid particles at an adequate velocity
to the coating on the mandrel. However, a preferred method of solid
particle application is to dip the mandrel/shell into a body of the
solid particles or expose it to a suspension of the solid
particles. It should be understood that the present invention is
not intended to be restricted to any one particular method of
applying particles. One possible method to apply solid particles to
some but not all of the shell is to mask off areas of the shell for
which particles are not to be applied and then apply the particles
to the non-masked areas.
[0075] The tacky flexible shell may then be immersed in a fluidized
(air-mixing) aqueous salt bath having regular cubic salt crystals
between about 10 to about 600 microns, or round crystals between
about 50-2000 microns or a combination thereof. Varying degrees of
texturing may be formed with the salt removal process by using
differently sized or shaped salt granules (for example, round salt
crystals versus angular salt crystals, large salt crystals versus
relatively small salt crystals, high density distribution of salt
crystals versus relatively low density distribution of salt
crystals), on different areas of the shell. The shell is rotated
for even coverage, removed, and then allowed to stabilize. After a
suitable period of stabilization, such as between about 5-20
minutes, the flexible shells may be dipped into an overcoat
dispersion. A suitable overcoat dispersion may be made using the
same material employed in the base layers. The flexible shells on
the mandrels are then mounted on a rack and allowed to volatilize,
such as, for example, about 15 minutes.
[0076] The entire silicone elastomer shell structure is vulcanized
or cured in an oven at elevated temperatures. The temperature of
the oven is preferably kept between about 200.degree. F. and about
350.degree. F. for a curing time preferably between about 20
minutes and about 1 hour, 40 minutes. Upon removal from the oven,
the mandrel/shell assembly is placed in a solvent for the solid
particles, and the solid particles allowed to dissolve. The solvent
does not affect the structure or integrity of the silicone
elastomer. When the solid particles have dissolved, the assembly is
removed from the solvent and the solvent evaporated. The shell can
then be stripped from the mandrel. At this point, it is preferable
to place the shell in a solvent for the solid particles and gently
agitate it to ensure complete dissolution of all the solid
particles. When the shell is removed from the solvent, the solvent
is evaporated.
[0077] Dissolving the solid particles leaves behind open,
interconnected, cavities in the surface of the shell where the salt
had been.
[0078] After finishing the shell according to the steps described
above, the steps required to make a finished breast implant
prosthesis may be similar to those known in the art. For example,
an opening left by the dip molding process is patched with uncured
sheeting, usually made of silicone rubber. Then, if the prosthesis
is to be filled with silicone gel, this gel is added and cured, the
filled prosthesis packaged, and the packaged prosthesis sterilized.
If the prosthesis is to be inflated with a saline solution, a
one-way valve is assembled and installed, the prosthesis is post
cured if required, and the prosthesis is then cleaned, packaged and
sterilized. A combination breast implant prosthesis can also be
made wherein a gel-filled sac is positioned inside the shell to be
surrounded by saline solution.
[0079] In addition to the aforementioned dipping process, the
flexible shell for the prosthetic implant may be formed using a
molding process. For example, a rotational molding process such as
described in Schuessler, U.S. Pat. No. 6,602,452 the entire
disclosure of which is incorporated herein, may be used. The
process for forming texturing on the exterior surface may be done
using a dipping technique after the shell is molded, but another
method is to roughen the inside of the mold. For example, a mold
having a generally smooth interior surface except for rough areas
as described above will produce an implant shell having discrete
fixation surfaces. The rotational molding process is advantageous
because the entire implant shell may be formed in relatively few
manufacturing steps.
[0080] Turning now to FIGS. 9A-9C, another embodiment of the
present invention is illustrated, hereinafter sometimes referred to
as a "dual plane breast implant." FIG. 9A shows a simplified
representation of anatomical placement of such a breast implant
300, and FIGS. 9B and 9C show a front view and side view,
respectively, of such an implant 300 in accordance with this
embodiment of the invention.
[0081] This implant 300 is particularly useful for dual plane
breast implant positioning, such as shown in FIG. 4C. In the dual
plane placement of breast implants, the upper portion of the
implant is covered by muscle while the lower portion of the implant
is not. For example, the implant is positioned such that the upper
region of the implant is located partially under and interfacing
the pectoralis major muscle 400 (see FIG. 9A) and a lower region is
located in the subglandular plane and not interfacing muscle
tissue.
[0082] In one embodiment, the implant 300 generally comprises a
relatively textured lower portion 310, e.g. lower pole, and a
relatively smooth or less textured upper portion 314, e.g. upper
pole. For example, when placed in a "dual plane" position in the
breast, the implant 300 of this embodiment invention may have a
stronger binding texture 320 on surfaces of the implant 300 that
are in contact with glandular tissue (where muscle does not
cover/contact the implant 300), and have a less binding surface 324
on surfaces of the implant 300 in contact with muscle tissue.
Although an anatomical, or "teardrop" shaped implant is shown in
FIGS. 9A and 9B, it should be appreciated that this dual plane
embodiment may comprises other shapes, for example, a "round"
shaped implant, such as shown in FIGS. 1A and 1B.
[0083] The lower portion 310 of the exterior surface of the implant
300 may have an open-cell textured surface which is designed or
structured to provide enhanced tissue ingrowth and adhesion. The
upper portion 312 of the exterior surface of the implant may have a
smooth surface, a closed cell textured surface, or another surface
configuration that is relatively less aggressive/less conducive to
tissue adhesion and ingrowth than the texture on the lower portion
310. Many varieties and permutations are contemplated and are
considered to fall within the scope of the invention.
[0084] One advantage of this embodiment 300 is that strong tissue
adherence would not be directly associated with attachment to
muscle tissue which may be more difficult to separate from a strong
binding texture. In addition, a weak or non-binding surface under
the muscle may allow the muscle to slide on the surface of the
implant and reduce the tension on the implant or the movement of
the implant with each flexing of the muscle. This embodiment may be
particularly advantageous in athletic woman because it may enhance
comfort and the ability to move the muscles of the chest wall while
enabling the implant to remain fixed and anchored in the glandular
tissue.
[0085] In another embodiment of the invention shown in FIGS. 10A
and 10B, an implant 400 is provided having a more aggressive
texture 412 for strong tissue binding or integration on the
anterior surface of the implant 400, and therefore fixation of the
implant on the anterior portion of the implant, and a smooth
surface or less textured surface 414 resulting in reduced fixation
on the posterior portion of the implant 400. One advantage of this
approach is that should the implant 400 need to be removed, the
portion of the implant 400 facing the rib cage can be more easily
released from the tissue and reduce the potential risks of surgical
separation of the implant from the tissue in proximity to the ribs
and plural cavity. Another advantage is that the smooth or less
textured posterior side of the implant would allow for some
movement or sliding of the implant 400, thereby reducing strain on
the implant itself when the implant is placed submuscularly or in a
dual plane position where constant flexing of the muscle would
potentially continually exert pressure on the implant. This
approach would be applicable to both smooth and shaped implants and
would reduce the potential for rotation. It would also have the
added benefit of potentially reducing contracture since the texture
would still provide a disruption of the alignment of the collagen
fibers in any developing capsule.
[0086] Although the invention has been described and illustrated
with a certain degree of particularity, it is understood that the
present disclosure has been made only by way of example, and that
numerous changes in the combination and arrangement of parts can be
resorted to by those skilled in the art without departing from the
scope of the invention, as hereinafter claimed.
* * * * *