U.S. patent application number 17/551296 was filed with the patent office on 2022-07-21 for prosthetic surgical sling.
The applicant listed for this patent is Beda B.G. Ruefer, Rebecca U. Ruefer. Invention is credited to Beda B.G. Ruefer, Rebecca U. Ruefer.
Application Number | 20220226091 17/551296 |
Document ID | / |
Family ID | |
Filed Date | 2022-07-21 |
United States Patent
Application |
20220226091 |
Kind Code |
A1 |
Ruefer; Beda B.G. ; et
al. |
July 21, 2022 |
PROSTHETIC SURGICAL SLING
Abstract
Disclosed is a process of making an expanded fluoropolymer,
e.g., PTFE, article is disclosed. The article is formed from a PTFE
resin, calendered, and then expanded (e.g., multiaxially) at an
elevated temperature. After cooling, the article is used to form a
surgically implanted device, e.g., a surgical prosthetic sling.
Inventors: |
Ruefer; Beda B.G.; (Bozeman,
MT) ; Ruefer; Rebecca U.; (Bozeman, MT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ruefer; Beda B.G.
Ruefer; Rebecca U. |
Bozeman
Bozeman |
MT
MT |
US
US |
|
|
Appl. No.: |
17/551296 |
Filed: |
December 15, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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63140052 |
Jan 21, 2021 |
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International
Class: |
A61F 2/00 20060101
A61F002/00; A61L 31/06 20060101 A61L031/06; A61L 31/14 20060101
A61L031/14; B29D 7/01 20060101 B29D007/01 |
Claims
1. An article usable as a supportive surgical implant, the article
comprising: an elongated body and a first end and a second end, the
elongated body formed of a biocompatible, bacteria-resistant
fluoropolymer material; the biocompatible, bacteria-resistant
fluoropolymer material being configured of a plurality of nodes and
a plurality of fibrils, the plurality of fibrils radiating from and
interconnecting the nodes multiaxially.
2. The article of claim 1 wherein the biocompatible,
bacteria-resistant fluoropolymer material comprises
Polytetrafluoroethylene (PTFE).
3. The article of claim 2 wherein the biocompatible,
bacteria-resistant fluoropolymer material comprises expanded PTFE
(ePTFE).
4. The article of claim 1 wherein the elongated body is
substantially planar.
5. The article of claim 1 wherein the article is substantially
microporous.
6. The article of claim 1 wherein the plurality of fibrils are
about 0.5-3 microns in length.
7. The article of claim 6, comprising: a plurality of pores defined
between the plurality of nodes and fibrils, the plurality of pores
having sizes less than or equal to 2 by 1 microns.
8. The article of claim 1 wherein the elongated body has a
thickness of about 0.60 mm.
9. The article of claim 1 wherein the article is configured for use
as a tissue support.
10. The article of claim 9 wherein the article is configured for
use as a pubovaginal sling.
11. The article of claim 9 wherein the first end is configured to
receive a first surgical placement aid, and the second end is
configured to receive a second surgical placement aid.
12. The article of claim 1 wherein the biocompatible,
bacteria-resistant fluoropolymer material comprises a microporous
structure which is relatively closed to ingrowth and bacterial
penetration.
13. A method for producing a supportive surgical implant device,
the method comprising: mixing a PTFE resin paste with an extrusion
aid; configuring a resin paste and the extrusion aid into a
pre-extrusion form; calendaring the pre-extrusion form to make a
PTFE article; drying the extrusion aid from the PTFE article;
reheating the PTFE article at a temperature higher than a drying
temperature used in the drying step, but lower than a melt
temperature of the PTFE article; multiaxially expanding the PTFE
article in at least two different directions to create a
node/fibril structure; restraining the PTFE article in an expanded
state and heating the PTFE article to a temperature above a thermal
transition temperature for the PTFE to lock the node/fibril
structure in place; allowing the article to cool; and configuring
the article for use as the supportive surgical implant.
14. The method of claim 13, wherein the multiaxially expanding step
occurs in X and Y directions at about 90 degrees relative to one
another.
15. The method of claim 13, wherein the multiaxially expanding step
occurs in greater than two directions.
16. The method of claim 13, comprising: forming the PTFE article
into a sheet; and causing at least a portion of the sheet to have
an elongated body and two ends.
17. The method of claim 16, comprising: configuring the ends of the
at least a portion of the sheet to attach to surgical placement
aids.
18. The method of claim 17, comprising: surgically implanting the
at least a portion of the sheet into a human body.
19. A pubovaginal support device configured for surgical implant,
the pubovaginal support device comprising: an elongated body formed
of expanded polytetrafluoroethylene; a first end and a second end
of the body; the fluoropolymer material being configured of a
plurality of nodes and a plurality of fibrils, the plurality of
fibrils radiating from and interconnecting the nodes
multiaxially.
20. The pubovaginal support device of claim 19 wherein the
plurality of fibrils are about 0.5-3 microns in length and a
plurality of pores defined between the plurality of nodes and
fibrils, the plurality of pores have sizes less than or equal to 2
by 1 microns.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 63/140,052 filed Jan. 21, 2021, the entire contents
of which are herein incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field
[0002] The disclosed embodiments relate generally to the field of
prosthetic medical devices. More specifically, the field relates to
the development of prosthetic medical slings implemented for
supporting internal body structures.
2. Description of the Related Art
[0003] Pubovaginal sling procedures are very prevalently used to
offer support needed to stabilize a patient's urethra or bladder.
The most common device used in executing such a process is an
elongated flexible strip constructed of a nonabsorbable
polypropylene mesh material, the ends of which can be anchored
elsewhere in the patient's body, and support is offered to prevent
incontinence.
SUMMARY
[0004] This summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the detailed description. This summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used to limit the scope of the claimed
subject matter. Other aspects and advantages will be apparent from
the following detailed description of the embodiments and the
accompanying drawing figures.
[0005] In embodiments, a medical support device includes an
elongated body comprised of an expanded fluoropolymer. The device
is used to support a body component, e.g., in embodiments, can be
used as a urethral sling or for other like applications. In some
embodiments, the elongated expanded fluoropolymer is
polytetrafluoroethylene (ePTFE). The ePTFE can, in embodiments, be
formed into an elongated sheet.
[0006] In some aspects, the techniques described herein relate to
an article usable as a supportive surgical implant, the article
including: an elongated body and a first end and a second end, the
elongated body formed of a biocompatible, bacteria-resistant
fluoropolymer material; the biocompatible, bacteria-resistant
fluoropolymer material being configured of a plurality of nodes and
a plurality of fibrils, the plurality of fibrils radiating from and
interconnecting the nodes multiaxially.
[0007] In some aspects, the techniques described herein relate to a
article wherein the biocompatible, bacteria-resistant fluoropolymer
material includes Polytetrafluoroethylene (PTFE).
[0008] In some aspects, the techniques described herein relate to a
article wherein the biocompatible, bacteria-resistant fluoropolymer
material includes expanded PTFE (ePTFE).
[0009] In some aspects, the techniques described herein relate to a
article wherein the elongated body is substantially planar.
[0010] In some aspects, the techniques described herein relate to a
article wherein the article is substantially microporous.
[0011] In some aspects, the techniques described herein relate to a
article wherein the plurality of fibrils are about 0.5-3 microns in
length.
[0012] In some aspects, the techniques described herein relate to a
article, including: a plurality of pores defined between the
plurality of nodes and fibrils, the plurality of pores having sizes
less than or equal to 2 by 1 microns.
[0013] In some aspects, the techniques described herein relate to a
article wherein the elongated body has a thickness of about 0.60
mm.
[0014] In some aspects, the techniques described herein relate to a
article wherein the article is configured for use as a tissue
support.
[0015] In some aspects, the techniques described herein relate to a
article wherein the article is configured for use as a pubovaginal
sling.
[0016] In some aspects, the techniques described herein relate to a
article wherein the first end is configured to receive a first
surgical placement aid, and the second end is configured to receive
a second surgical placement aid.
[0017] In some aspects, the techniques described herein relate to a
article wherein the biocompatible, bacteria-resistant fluoropolymer
material includes a microporous structure which is relatively
closed to ingrowth and bacterial penetration.
[0018] In some aspects, the techniques described herein relate to a
method for producing a supportive surgical implant device, the
method including: mixing a PTFE resin paste with an extrusion aid;
configuring a resin paste and the extrusion aid into a
pre-extrusion form; calendaring the pre-extrusion form to make a
PTFE article; drying the extrusion aid from the PTFE article;
reheating the PTFE article at a temperature higher than a drying
temperature used in the drying step, but lower than a melt
temperature of the PTFE article; multiaxially expanding the PTFE
article in at least two different directions to create a
node/fibril structure; restraining the PTFE article in an expanded
state and heating the PTFE article to a temperature above a thermal
transition temperature for the PTFE to lock the node/fibril
structure in place; allowing the article to cool; and configuring
the article for use as the supportive surgical implant.
[0019] In some aspects, the techniques described herein relate to a
method, wherein the multiaxially expanding step occurs in X and Y
directions at about 90 degrees relative to one another.
[0020] In some aspects, the techniques described herein relate to a
method, wherein the multiaxially expanding step occurs in greater
than two directions.
[0021] In some aspects, the techniques described herein relate to a
method, including: forming the PTFE article into a sheet; and
causing at least a portion of the sheet to have an elongated body
and two ends.
[0022] In some aspects, the techniques described herein relate to a
method, including: configuring the ends of the at least a portion
of the sheet to attach to surgical placement aids.
[0023] In some aspects, the techniques described herein relate to a
method, including: surgically implanting the at least a portion of
the sheet into a human body.
[0024] In some aspects, the techniques described herein relate to a
pubovaginal support device configured for surgical implant, the
pubovaginal support device including: an elongated body formed of
expanded polytetrafluoroethylene; a first end and a second end of
the body; the fluoropolymer material being configured of a
plurality of nodes and a plurality of fibrils, the plurality of
fibrils radiating from and interconnecting the nodes
multiaxially.
[0025] In some aspects, the techniques described herein relate to a
pubovaginal support device wherein the plurality of fibrils are
about 0.5-3 microns in length and a plurality of pores defined
between the plurality of nodes and fibrils, the plurality of pores
have sizes less than or equal to 2 by 1 microns.
[0026] Regardless of the particular configuration involved, the
elongated medical support device can have first and second ends
both receivable by a placement tool designed to aid with implanting
the device into the human body in a supporting capacity regarding
an internal structure. In some embodiments the device is a
sling.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0027] Illustrative embodiments are described in detail below with
reference to the attached drawing figures, which are incorporated
by reference herein and wherein:
[0028] FIG. 1A shows an overall view for a first embodiment;
[0029] FIG. 1B shows a cross sectional view taken from line 1B-1B
in FIG. 1A;
[0030] FIG. 1C depicts the article (shown in FIGS. 1A-B) as it
might be attached to placement aids used for implant; and
[0031] FIG. 2 is a micrograph taken of the material manufactured
according to the process steps expressed herein.
[0032] The drawing figures do not limit the invention to the
specific embodiments disclosed and described herein. The drawings
are not necessarily to scale, emphasis instead being placed upon
clearly illustrating the principles of the invention.
DETAILED DESCRIPTION
[0033] The following detailed description references the
accompanying drawings that illustrate specific embodiments in which
the invention can be practiced. The embodiments are intended to
describe aspects of the invention in sufficient detail to enable
those skilled in the art to practice the invention. Other
embodiments can be utilized and changes can be made without
departing from the scope of the invention. The following detailed
description is, therefore, not to be taken in a limiting sense. The
scope of the invention is defined only by the appended claims,
along with the full scope of equivalents to which such claims are
entitled.
[0034] In this description, references to "one embodiment," "an
embodiment," or "embodiments" mean that the feature or features
being referred to are included in at least one embodiment of the
technology. Separate references to "one embodiment," "an
embodiment," or "embodiments" in this description do not
necessarily refer to the same embodiment and are also not mutually
exclusive unless so stated and/or except as will be readily
apparent to those skilled in the art from the description. For
example, a feature, structure, act, etc. described in one
embodiment may also be included in other embodiments, but is not
necessarily included. Thus, the technology can include a variety of
combinations and/or integrations of the embodiments described
herein.
[0035] Synthetic slings have been available for implant procedures
for many decades. The most common form of sling is constructed of
polypropylene, which is typically comprised of woven or knit
filaments. A polypropylene sling presents open structure which
allows bacteria to penetrate. This can lead to post-operative
infection. Although these devices have been implanted in many
thousands of patients, there remain many post-implantation problems
that have yet to be resolved. Most of these problems are clinically
significant, and can end with surgical retrieval of the devices,
which can lead to internal tissue damage.
[0036] One problem with these prior art polypropylene mesh slings
is damage that can be caused upon surgical implant. Those skilled
in the art will recognize that during surgery the polypropylene
mesh sling is worked through bodily tissues, e.g., being pushed or
pulled therethrough using needles or other devices. The edges of
these prior art slings may be rough, and when passed through the
body during surgical implant can create tissue damage, e.g., scar
tissue, etc.
[0037] Any limited damage created upon implant of the polypropylene
sling is not necessarily considered a bad thing, in that the damage
causes an immediate inflammatory response, which ultimately helps
incorporate the device structurally. But this damage can compromise
tissues in undesirable ways also.
[0038] Another problem is that the polypropylene mesh degrades over
time. This degradation can result in migration of sling segments or
filaments, or even extrusion of the same. These obvious failures
create harm, and often result in the need for removal of an
already-implanted sling by a surgery far more complicated and
potentially harmful than the initial implant procedure, and can
leave behind massive scar tissue, as well as result in chronic pain
moving forward.
[0039] Another problem is that of infection. The vulnerability of
the polypropylene to infection is due in large part to the nature
of the mesh material. Following implantation of a conventional
polypropylene mesh sling, it is considered desirable that the
surrounding tissues grow into the device. This ingrowth is seen as
necessary to secure the polypropylene device in place. But this
also makes the device extremely difficult to remove surgically,
e.g., in the case of complications such as infection or structural
degradation over time. Many times, surgery to remove the sling
creates serious problems to the tissues on or around the
implant.
[0040] The invention disclosed herein is a prosthetic medical sling
made of a novel synthetic material, in embodiments, a relatively
closed expanded Polytetrafluoroethylene structure. The inventive
design of the medical device provides for a strong, supportive,
biocompatible sling that resists bacterial invasion and
disintegration.
[0041] The prosthetic sling embodiments disclosed herein overcome
the aformentioned problems significantly.
[0042] More specifically, the embodiments described herein comprise
a novel synthetic prosthetic medical sling that is biocompatible,
resists bacterial infection, exhibits significant long-term
strength to support tissues, does not promote massive scar tissue,
and will not deteriorate over time. Further, the sling embodiments
exhibit strength adequate for intended use, are supple and tissue
compliant to minimize scar tissue formation, and are durable, as
PTFE, a fluoropolymer, is known to be resistant to
biodegradation.
[0043] Embodiments are comprised of a processed fluoropolymer, such
as Polytetrafluoroethylene (PTFE). Embodiments disclosed in the
figures herein incorporate expanded PTFE, or "ePTFE" which is
formed by expansion under heat. An ePTFE article can be
manufactured to have fibril lengths such that the article is
relatively closed structured to prevent the infiltration of
bacteria, yet supple for tissue compliance, and adequately strong
for its intended use as a tissue support device. And of course, as
ePTFE, it is fully biocompatible and will not degrade.
[0044] The micro porous structure of known ePTFE articles is
characterized by a plurality of nodes that are connected together
by a plurality of fibrils. The nodes are essentially solid PTFE,
having a density of about 2.0-2.2 grams per cubic centimeter,
whereas the density of the expanded material is less than about 2.0
grams per cubic centimeter. The shape, size and orientation of the
nodes and fibrils within the structure can be controlled by varying
the expansion rate, expansion ratio, number of expansion axes and
other processing parameters to yield many different structures. It
is also known that properties such as the expandability and
microstructure of the expanded article vary with the molecular
weight, particle size and other physical characteristics of the
PTFE resin.
[0045] An embodiment of the ePTFE article useable as an implant
device (e.g., sling) is configured as a flat (roughly/substantially
planar) elongated sheet embodiment as seen in FIGS. 1A and 1B. The
body is made of a relatively closed structure, high strength,
expanded fluoropolymer.
[0046] The embodiments above have shown no ingrowth as well as no
bacterial penetration. Thus, they avoid the well-known infection
problems existing in the polypropylene prior art devices.
Additionally, because ingrowth is avoided, surgical removal is
relatively easy to accomplish, if necessary, and leaves little, if
any, scar tissue or other damage.
[0047] An embodiment 100 is shown in perspective in FIG. 1A. FIG.
1B shows a cross section taken at 1B-1B in FIG. 1A. The article 100
usable as a surgical supporting device includes a first end 102, a
second end 104, and a substantially flat elongated body 106
(configured of a fluoropolymer in embodiments). The elongated
substantially flat body 106 of the first version 100 is, in
embodiments, comprised of multiaxially expanded PTFE that will
ultimately reflect a node/fibril structure that can be made
according to the practices discussed hereinafter.
[0048] The article is made, in embodiments, according to a process.
More specifically, the article is produced by expanding PTFE in
multiple dimensions. This can be accomplished by mixing a resin
paste with an extrusion-aid such as mineral spirits, and then
compressing the paste at relatively low pressures into a
pre-extrusion form, e.g., as a pellet.
[0049] In embodiments, the material is extruded as a substantially
flat article.
[0050] The PTFE article is then calendered while wet to a desired
thickness. Because the article will be partially wet with mineral
spirits, the process then moves on to a drying step where the
lubricant is removed by subjecting it to temperature slightly above
the boiling point of the lubricant (e.g., about 150.degree. C.),
and far below the sintering or coalescing temperature of the
polymer, generally at about 327.degree. C. in embodiments.
[0051] Next, the article, in embodiments, is reheated at a
temperature higher than the drying temperature, but below the melt
temperature, e.g., above 240.degree. C., in embodiments, or about
250.degree. C. in more specific embodiments.
[0052] Next, the article is multiaxially expanded. This expansion
could occur both longitudinally and laterally (in directions at 90
degrees to each other). Alternatively, those skilled in the art
will recognize that the expansion could be accomplished by machines
capable of expanding additional directions (e.g., 8 axis, 16 axis,
or other systems could be used). The process, ideally, will result
in fibril lengths of about 0.5-3 microns. In embodiments, the
resulting pore size is about less than or equal to 2 by 1 microns.
This will not allow for ingrowth, and the multi axial expansion
gives great strength. The extent of expansion of the PTFE makes the
material softer, and here, that softness makes the ultimate device
perform well.
[0053] Next, in a final heat-treating step, the material is
restrained in its expanded state and heated above the thermal
transition temperature at about 350.degree. C. to lock the
structure in place.
[0054] Now expanded and locked, the PTFE article is allowed to cool
over a period of time at a lower temperature, e.g., at ambient.
[0055] Once the article has been processed as discussed above, the
article can be presented for use along with existing implant
systems and/or methods. The article can also be configured for use
as a surgical implant.
[0056] The article can also be cut into desired sections or
otherwise configured in ways making each section able to function
as an individual sling.
[0057] As an optional additional step, an antimicrobial coating can
be added to applied to the PTFE strip.
[0058] The ends of the cut strips (e.g., ends 102 and 104) can be
configured for attachment to placement aids (e.g., needles) at each
end of the article 100. FIG. 1C shows the PTFE article 100 attached
to each of the placement aids 126 and 128.
[0059] The first and second ends 102 and 104 in FIG. 2 are shown
being at connection locations 130 and 132. Those skilled in the art
will recognize that numerous different sorts of ways that the
connection aids 126 and 128 are connected to ends 102 and 104 exist
in the art, e.g., the ends can be: (i) secured into clamps existing
on each placement aids 126 and 128 (ii) ends 102 and 104 can be
apertured for receipt of snaps on each placement aid (126 and 128);
(iii) the ends of the sling 100 can be knotted and then secured
into a V-shaped grooves formed into each aid (126 and 128); (iv)
the ends can be attached using sutures; (v) attached using trocars;
or (vi) other methods.
Example 1
[0060] In an embodiment, a resin paste was formed by blending 100%
PTFE fine powder with an extrusion-aid (e.g., mineral spirits). The
resulting resin paste was then formed into an extrusion pellet.
[0061] The PTFE article was extruded as a rectangular cross
section, and calendered to a thinner cross section while wet. The
ultimate thickness was about 0.60 mm after calendering.
[0062] After calendering, the lubricant was removed by subjecting
the article to heat at a temperature of about 150.degree. C. in
order to dry the article (remove the mineral spirits).
[0063] The article was then reheated at about 250.degree. C. but
below the melt temperature and multiaxially expanded in two
dimensions longitudinally and laterally (in directions offset by 90
degrees).
[0064] Next, the material was restrained in its expanded state, and
heated above the thermal transition temperature at about
350.degree. C. to lock the structure in place.
[0065] Now expanded, the PTFE article was allowed to cool over a
period of time at a lower temperature, e.g., at ambient.
[0066] The extent of expansion of the PTFE was shown to give the
material softness and other desired parameters discussed above
making it ideal for use as a surgical sling. FIG. 2 is a micrograph
taken of the material manufactured according to the processes
discussed above. Referring to the figure, it can be seen that the
article has a fibril length which is essentially less than 2
micron. This size inhibits cells or bacteria from penetrating the
material. Another noteworthy property is that the fibrils occupy
limited space in the article, whereas the node sizes are relatively
much larger. As can be seen from the FIG. 2 micrograph, more than
about 80% of the area is comprised of solid nodes.
[0067] Although the descriptions above relate to the use of ePTFE
strips as prosthetic slings to stabilize a patient's urethra or
bladder as described above, they could also be useful in providing
support for other pelvic organs. Additionally, multiple strips
could be used together for certain applications. Further, the
articles could be used for the support of rectal muscles in other
applications.
[0068] Many different arrangements of the various components
depicted, as well as components not shown, are possible without
departing from the spirit and scope of what is claimed herein.
Embodiments have been described with the intent to be illustrative
rather than restrictive. Alternative embodiments will become
apparent to those skilled in the art that do not depart from what
is disclosed. A skilled artisan may develop alternative means of
implementing the aforementioned improvements without departing from
what is claimed.
[0069] It will be understood that certain features and
subcombinations are of utility and may be employed without
reference to other features and subcombinations and are
contemplated within the scope of the claims. Not all steps listed
in the various figures need be carried out in the specific order
described.
* * * * *