U.S. patent application number 14/730723 was filed with the patent office on 2015-12-10 for dynamic biometric mesh.
This patent application is currently assigned to VIVEX BIOMEDICAL INC.. The applicant listed for this patent is Vivex Biomedical, Inc.. Invention is credited to Timothy Ganey, P. Pravin Reddy.
Application Number | 20150351889 14/730723 |
Document ID | / |
Family ID | 54768663 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150351889 |
Kind Code |
A1 |
Reddy; P. Pravin ; et
al. |
December 10, 2015 |
Dynamic Biometric Mesh
Abstract
A dynamic biometric mesh (10) has a plurality of radial members
(30) and a plurality of catenaries (20). Each catenary (20) extends
between and is fixed to at least one pair of adjacent radial
members (30). The plurality of catenaries (20) and radial members
(30) form a low mass structural system arranged in an architecture
configured to be structurally stable in tension and pliable for
deployment and integration with biologic tissue.
Inventors: |
Reddy; P. Pravin; (Atlanta,
GA) ; Ganey; Timothy; (Tampa, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Vivex Biomedical, Inc. |
Marietta |
GA |
US |
|
|
Assignee: |
VIVEX BIOMEDICAL INC.
Marietta
GA
|
Family ID: |
54768663 |
Appl. No.: |
14/730723 |
Filed: |
June 4, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62008051 |
Jun 5, 2014 |
|
|
|
Current U.S.
Class: |
606/151 ;
623/8 |
Current CPC
Class: |
A61F 2/0063 20130101;
A61F 2/12 20130101; A61F 2002/0068 20130101 |
International
Class: |
A61F 2/00 20060101
A61F002/00; A61F 2/12 20060101 A61F002/12 |
Claims
1. A dynamic biometric mesh comprises: a plurality of radial
members; a plurality of catenaries, each catenary extending between
and fixed to at least one pair of adjacent radial members; and
wherein the plurality of catenaries and radial members form a low
mass structural system arranged in an architecture configured to be
structurally stable in tension and pliable for deployment and
integration with biologic tissue.
2. The dynamic biometric mesh of claim 1 further comprises: a
central region or opening from which the radial members extend
outwardly to ends defining an outer perimeter; and wherein the
plurality of catenaries are arranged in circumferential extending
rows spaced along lengths of the radial members.
3. The dynamic biometric mesh of claim 2 wherein adjacent
circumferential extending rows are more closely spaced near the
center region and increase in spacing towards the outer
perimeter.
4. The dynamic biometric mesh of claim 1 wherein the plurality of
catenaries are fixed to radial members and the sag or hang between
the radial members in the rage from 0, a straight line, or greater
than 0 evidencing a curved hanging path, each catenary having zero
tension in a flat plane when formed as a mesh.
5. The dynamic biometric mesh of claim 1 wherein one or more
catenaries has a positive sag or hang (a), (a) being a drop or sag
between a straight line passing through the fixed ends at the
radial member.
6. The dynamic biometric mesh of claim 1 wherein the catenaries are
elastic having a defined stretch under tension.
7. The dynamic biometric mesh of claim 6 wherein the radial members
are elastic having a defined stretch under tension.
8. The dynamic biometric mesh of claim 1 wherein the mesh is
conformable about a convex curvature.
9. The dynamic biometric mesh of claim 8 wherein the outer
perimeter has a plurality of attachment or anchoring points to
attach the mesh to tissue.
10. The dynamic biometric mesh of claim 9 wherein the mesh can be
stretched to the attachment points to pre-tension the mesh along
the attachments.
11. The dynamic biometric mesh of claim 10 wherein the
pre-tensioning of the mesh places a tension on the catenaries and
wherein the catenaries achieve a tensioned equilibrium after being
affixed.
12. The dynamic biometric mesh of claim 11 wherein the catenaries
stretch under expansion or retract under contraction in relation to
the movement of the tissue to which the mesh is affixed.
13. The dynamic biometric mesh of claim 1 wherein the mesh has an
asymmetric configuration having an upper hemisphere extending above
the central opening of increased elasticity or stretch and a lower
hemisphere having a reduced elasticity or stretch.
14. The dynamic biometric mesh of claim 13 wherein the lower
hemisphere has a plurality of struts, each strut extending
diagonally between adjacent catenaries and adjacent radial
members.
15. The dynamic biometric mesh of claim 14 wherein the struts are
attached to intersections of a respective catenary and radial
members.
16. The dynamic biometric mesh of claim 12 wherein at least an
upper portion or hemisphere of the mesh can expand under tension at
least to 150% from its as formed unattached structure.
17. The dynamic biometric mesh of claim 16 wherein the radial
members and the catenaries have the same elasticity.
18. The dynamic biometric mesh of claim 14 wherein the struts,
radial members and catenaries have the same elasticity.
19. The dynamic biometric mesh of claim 14 wherein the struts of
the lower hemisphere are positioned diagonally at each intersection
and can be selectively removed by cutting one or more struts to
tune the structure of the mesh to accommodate the tissue to which
the mesh is attached.
20. The dynamic biometric mesh of claim 1 wherein one or more of
the plurality of catenaries is formed as a shelf having a width (w)
and a length (l) creating top and bottom surface areas to affix
biological materials, chemicals or pharmaceuticals to enhance
tissue integration.
21. The dynamic biometric mesh of claim 1 wherein the mesh is
formed by weaving monofilaments in a multi-ply configuration.
22. The dynamic biometric mesh of claim 21 wherein the mesh is a
three ply configuration.
23. The dynamic biometric mesh of claim 1 wherein the mesh
redirects forces from lateral tension into rostral-caudal alignment
to direct reconstitution and normalize tissue repair.
24. The dynamic biometric mesh of claim 1 wherein the mesh is a
multi-tiered structure having two or more connected layers of
mesh.
25. The dynamic biometric mesh of claim 1 wherein the mesh
distributes tension across the catenaries and radial members to
dissipate dynamic forces at the anchoring points.
26. The dynamic biometric mesh of claim 1 wherein the mesh is
configured for attachment to an abdominal wall for use in repair of
abdominal wall hernias.
27. The dynamic biometric mesh of claim 1 wherein the mesh is
configured to provide dynamic stabilization and support of breast
tissue.
28. The dynamic biometric mesh of claim 1 wherein the mesh is
degradably defined by the material composition to be selectively
absorbed or biologically integrated into the tissue to which it is
attached.
29. The dynamic biometric mesh of claim 1 wherein the mesh is
formed using one or more techniques such as cast, printed,
corrugated, embossed, extruded, die cut, welded, laser etched,
laser modified tissue mimetic biodynamic or any combination
thereof.
30. The dynamic biometric mesh of claim 29 wherein the mesh has
random or preferred surface orientation and roughness.
31. The dynamic biometric mesh of claim 1 wherein intrinsic cell
instruction properties are engineered into fibers which make up the
catenaries and radial members using laser etching, the cell
instruction properties of the mesh promotes incorporation of the
mesh into surrounding tissues by promoting tissue ingrowth.
32. The dynamic biometric mesh of claim 1 wherein metal salts are
incorporated into fiber of the catenaries and radial members to act
as competitive inhibitors to mediators of inflammatory
response.
33. The dynamic biometric mesh of claim 32 wherein these metal
salts include titanium dioxide as a competitive inhibitor of
metalloprotease mediators of the inflammatory response.
34. The dynamic biometric mesh of claim 1 wherein the mesh is
conditioned with autologous mesenchymal stem cells (MSCs) derived
from processed adipose tissue, and consistent with the stromal
vascular fraction (SVF).
35. The dynamic biometric mesh of claim 34 wherein the mesh is
conditioned with the MSCs in a bioreactor in advance of insertion
into the hernia defect.
36. The dynamic biometric mesh of claim 35 wherein the mesh has a
matrix to enhance cell attachment, stimulate differentiation and
accentuate force transduction in alignment of the cell
orientation.
37. The dynamic biometric mesh of claim 36 wherein the mesh is a
biosynthetic composite structure customized to the subject and
accelerates incorporation into adjacent tissues.
38. The dynamic biometric mesh of claim 1 wherein the mesh is
manufactured using a 3-D printing technology.
39. The dynamic biometric mesh of claim 38 wherein the mesh is made
on demand and to precisely match the hernia defect in the subject
based on non-invasive measurements including physical
examination.
40. The dynamic biometric mesh of claim 1 wherein the mesh is
formed as a broad platform of uniform isotropic distributed radial
members and catenaries or struts formed by either printed, laser
cut, die cut, embossed, sprayed on suitable differential electrodes
to align charge, or other means.
41. The dynamic biometric mesh of claim 40 wherein the catenaries,
radial members or struts are over sprayed with collagen, PGLA, PCL,
Poly-imides, or other bio-absorbable polymers.
42. The dynamic biometric mesh of claim 1 wherein the mesh emulates
zoomorphic design, specifically that of a spider web, and is
intended to possess an open architecture thus reducing infection
and inflammation.
43. The dynamic biometric mesh of claim 42 wherein the stress or
elongation characteristics of the mesh are suited to accommodating
the cyclical load bearing properties of the ventral abdominal wall
and the interstices of the mesh are smaller than 12 mm or less.
44. The dynamic biometric mesh of claim 1 wherein the mesh
incorporates one or more features in cross section of a woody stem,
of a plant branching interface, demonstrates regular and randomized
cells, Fibonacci and ordered arrays, varying diameters and regular,
ordered arrays of inner cells any of which imparting structural
tension to lateral distortion without imposing material
stiffness.
45. The dynamic biometric mesh of claim 1 wherein the tensile
strength of the catenaries or radial members are formed as fibers
having a tensile strength in the range of 50 to 150 N/m.
46. The dynamic biometric mesh of claim 45 wherein the tensile
strength of the catenaries or radial members are formed as fibers
having a tensile strength of 100 N/m.
47. The dynamic biometric mesh of claim 1 wherein the catenaries
and radial members have a fiber diameter of 0.2 mm or greater.
48. The dynamic biometric mesh of claim 47 wherein the catenaries
and radial members have a fiber diameter of 0.26 mm.
49. The dynamic biometric mesh of claim 45 wherein the Young's
modulus of component fibers is 34 GPa or greater.
50. The dynamic biometric mesh of claim 9 wherein the suture pull
out strength is at least 5.5 kg at the outer perimeter of the mesh.
Description
TECHNICAL FIELD
[0001] The present invention relates to meshes for supporting
tissues generally, more particularly, a mesh for hernia repair or
breast support.
BACKGROUND OF THE INVENTION
[0002] Ventral abdominal hernias are common and associated with
significant morbidity. The most common cause for ventral hernias
remains previous open abdominal surgery, although prolapse via
epigastric and lower abdominal muscle wall are common as well. Over
100,000 ventral hernia repairs are performed in the USA annually.
Untreated abdominal hernias can result in incarceration of bowel;
organ prolapse; bowel obstruction; strangulation of bowel; and even
death.
[0003] Rising obesity rates have resulted in increased recurrence
rates of ventral hernias reported as high as 11% following open
abdominal surgical procedures
[0004] Long-term prospective studies have established mesh repair
of ventral hernia as superior to primary suture repair. As noted by
Dr. S. Saureland, the incidence of recurrent herniation is 10-fold
higher with direct repair compared to a mesh prosthesis
[0005] Existing prosthetic meshes are associated with a range of
problems as well, including significant recurrent rates (10-30%);
fibrosis; chronic pain; stiffness of the abdominal wall; intestinal
fistula; infection; recurrences; anchor point failures; thromboses;
calcification; and unfavorable bowel interactions.
[0006] Existing ventral hernia mesh technologies are biased in
design as static load bearing systems, and fail to account for
tensional integrity, or tensegrity; a model more appropriate to
biologic systems. The preference for stiff and static meshes arises
from the belief that flexible meshes are prone to resulting in
abdominal bulges following herniorrhaphy; however, stiff meshes
fail to dissipate tensile forces across the abdominal wall and
instead absorb these energies which may contribute to their
ultimate failure particularly at the anchoring points. Furthermore,
many meshes are composed of non-biocompatible materials and thus
destined for encapsulation that promote chronic inflammatory
responses at the implantation site. Many current mesh designs rely
on a large mass of material resulting in thick scar formation which
in turn leads to stiffness of the abdominal wall and chronic pain.
Finally, no current mesh is manufactured to match the hernia defect
with regard to size, mechanical profile, or consider integrating
dynamic tensile property during the healing process.
[0007] The present invention disclosed herein provides a novel
ventral abdominal mesh designed to address problems associated with
ventral hernias that integrate the principles of tensegrity,
biocompatibility, and biometric customization.
SUMMARY OF THE INVENTION
[0008] A dynamic biometric mesh has a plurality of radial members
and a plurality of catenaries. Each catenary extends between and is
fixed to at least one pair of adjacent radial members. The
plurality of catenaries and radial members form a low mass
structural system arranged in an architecture configured to be
structurally stable in tension and pliable for deployment and
integration with biologic tissue.
[0009] Biometric mesh further has a central region or opening from
which the radial members extend outwardly to ends defining an outer
perimeter. The plurality of catenaries are preferably arranged in
circumferential extending rows spaced along lengths of the radial
members. Adjacent circumferential extending rows are more closely
spaced near the center region and increase in spacing towards the
outer perimeter.
[0010] The dynamic biometric mesh of the invention has the
plurality of catenaries fixed to radial members and the sag or hang
between the radial members in the rage from 0, a straight line, or
greater than 0 evidencing a curved hanging path. Each catenary has
zero tension in a flat plane when formed as a mesh. The dynamic
biometric mesh of at least one embodiment has one or more
catenaries with a positive sag or hang (a), (a) being a drop or sag
between a straight line passing through the fixed ends at the
radial member. Preferably all of the catenaries are elastic having
a defined stretch under tension. Similarly it is preferred that the
radial members are elastic having a defined stretch under
tension.
[0011] Ideally, the dynamic biometric mesh is conformable about a
convex curvature. The dynamic biometric mesh has the outer
perimeter having a plurality of attachment or anchoring points to
attach the mesh to tissue. The mesh can be stretched to the
attachment points to pre-tension the mesh along the attachments.
The pre-tensioning of the mesh places a tension on the catenaries
and wherein the catenaries achieve a tensioned equilibrium after
the mesh is anchored or affixed to the tissue. The catenaries
stretch under expansion or retract under contraction in relation to
the movement of the tissue to which the mesh is affixed. In one
embodiment, the dynamic biometric mesh has an asymmetric
configuration having an upper hemisphere extending above the
central opening of increased elasticity or stretch and a lower
hemisphere having a reduced elasticity or stretch. The lower
hemisphere has a plurality of struts, each strut extending
diagonally between adjacent catenaries and adjacent radial members.
The struts are preferably attached to intersections of a respective
catenary and radial members. The struts of the lower hemisphere are
positioned diagonally at each intersection and can be selectively
removed by cutting one or more struts to tune the structure of the
mesh to accommodate the tissue to which the mesh is attached.
[0012] The dynamic biometric mesh allows for at least an upper
portion or hemisphere of the mesh to expand under tension at least
to 150% from its as formed unattached structure. The radial members
and the catenaries have the same elasticity. The struts, radial
members and catenaries may have the same elasticity.
[0013] The dynamic biometric mesh of another embodiment has one or
more of the plurality of catenaries formed as a shelf having a
width (w) and a length (1) creating top and bottom surface areas to
affix biological materials, chemicals or pharmaceuticals to enhance
tissue integration. The dynamic biometric mesh can be formed by
weaving monofilaments in a multi-ply configuration. The dynamic
biometric mesh is a three ply configuration. Preferably, the
dynamic biometric mesh can be a multi-tiered structure having two
or more connected layers of mesh.
[0014] The dynamic biometric mesh redirects forces from lateral
tension into rostral-caudal alignment to direct reconstitution and
normalize tissue repair. The dynamic biometric mesh, as designed,
distributes tension across the catenaries and radial members to
dissipate dynamic forces at the anchoring points. The dynamic
biometric mesh can be configured for attachment to an abdominal
wall for use in repair of abdominal wall hernias or to provide
dynamic stabilization and support of breast tissue. The dynamic
biometric mesh can be degradably defined by the material
composition to be selectively absorbed or biologically integrated
into the tissue to which it is attached. The dynamic biometric mesh
can be formed using one or more techniques such as cast, printed,
corrugated, embossed, extruded, die cut, welded, laser etched,
laser modified tissue mimetic biodynamic.
[0015] The dynamic biometric mesh can have random or preferred
surface orientation and roughness. The dynamic biometric mesh can
be made with intrinsic cell instruction properties engineered into
fibers which make up the catenaries and radial members using laser
etching. The cell instruction properties of the mesh promote
incorporation of the mesh into surrounding tissues by promoting
tissue ingrowth. Alternatively, or in combination with the cell
instruction, the dynamic biometric mesh may also include metal
salts which are incorporated into fiber of the catenaries and
radial members to act as competitive inhibitors to mediators of
inflammatory response. These metal salts include titanium dioxide
as a competitive inhibitor of metalloprotease mediators of the
inflammatory response. The dynamic biometric mesh can be
conditioned with autologous mesenchymal stem cells (MSCs) derived
from processed adipose tissue, and consistent with the stromal
vascular fraction (SVF). The mesh can be conditioned with the MSCs
in a bioreactor in advance of insertion into the hernia defect. The
dynamic biometric mesh can include a matrix to enhance cell
attachment, stimulate differentiation and accentuate force
transduction in alignment of the cell orientation. The dynamic
biometric mesh preferably is a biosynthetic composite structure
customized to the subject and accelerates incorporation into
adjacent tissues. The dynamic biometric mesh can be manufactured
using a 3-D printing technology, wherein the mesh is made on demand
and to precisely match the hernia defect in the subject based on
non-invasive measurements including physical examination. The
dynamic biometric mesh is formed as a broad platform of uniform
isotropic distributed radial members and catenaries or struts
formed by either printed, laser cut, die cut, embossed, sprayed on
suitable differential electrodes to align charge, or other means.
The catenaries, radial members or struts can be over sprayed with
collagen, PGLA, PCL, Poly-imides, or other bio-absorbable polymers.
The dynamic biometric mesh, in one or more embodiments, emulates
zoomorphic design, specifically that of a spider web, and is
intended to possess an open architecture thus reducing infection
and inflammation. The dynamic biometric mesh has the stress or
elongation characteristics of the mesh to be suited to
accommodating the cyclical load bearing properties of the ventral
abdominal wall and the interstices of the mesh are smaller than 12
mm or less. The dynamic biometric mesh may incorporate one or more
features in cross section of a woody stem, of a plant branching
interface, demonstrates regular and randomized cells, Fibonacci and
ordered arrays, varying diameters and regular, ordered arrays of
inner cells any of which imparting structural tension to lateral
distortion without imposing material stiffness. The catenaries and
radial members are preferably formed as fibers having a tensile
strength in the range of 50 to 150 N/m, preferably about 100 N/m.
The catenaries and radial members may have a fiber diameter of 0.2
mm or greater, preferably a fiber diameter of 0.26 mm. The dynamic
biometric mesh preferably has the Young's modulus of component
fibers being 34 GPa or greater. The suture pull out strength is at
least 5.5 kg at the outer perimeter of the mesh.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The invention will be described by way of example and with
reference to the accompanying drawings in which:
[0017] FIG. 1A is a reduced mass mesh made in accordance with a
first embodiment of the invention.
[0018] FIG. 1B is the same mesh as FIG. 1A wherein the catenaries
are curved, each being suspended between two points on pairs of
radial members.
[0019] FIG. 2 is a second embodiment mesh with stiffening
struts.
[0020] FIG. 3 is a third embodiment with an alternative mesh
design.
[0021] FIG. 4 is a fourth embodiment alternative mesh design.
[0022] FIG. 5 is a multi-layered mesh.
[0023] FIG. 6 is a depiction of the mesh on a convex surface.
[0024] FIGS. 7A and 7B are a fifth embodiment mesh for use in
breast surgery as a breast support structure.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The present invention employs a plurality of catenary
members or fibers hereinafter called catenaries.
[0026] In physics and geometry, a catenary is the curve that an
idealized hanging chain or cable assumes under its own weight when
supported only at its ends. The curve has a U-like shape,
superficially similar in appearance to a parabola, but it is not a
parabola: it is a (scaled, rotated) graph of the hyperbolic cosine.
The curve appears in the design of certain types of arches and as a
cross section of the catenoid--the shape assumed by a soap film
bounded by two parallel circular rings.
[0027] The catenary is also called the "alysoid", "chainette", or,
particularly in the material sciences, "funicular".
[0028] Mathematically, the catenary curve is the graph of the
hyperbolic cosine function. The surface of revolution of the
catenary curve, the catenoid, is a minimal surface, specifically a
minimal surface of revolution. The mathematical properties of the
catenary curve were first studied by Robert Hooke in the 1670's,
and its equation was derived by Leibniz, Huygens and Johann
Bernoulli in 1691.
[0029] Catenaries and related curves are used in architecture and
engineering, in the design of bridges and arches, so that forces do
not result in bending moments.
[0030] Over any horizontal interval, the ratio of the area under
the catenary to its length equals a, independent of the interval
selected. The catenary is the only plane curve other than a
horizontal line with this property. Also, the geometric centroid of
the area under a stretch of catenary is the midpoint of the
perpendicular segment connecting the centroid of the curve itself
and the x-axis.
[0031] In an elastic catenary, the chain is replaced by a spring
which can stretch in response to tension. The spring is assumed to
stretch in accordance with Hooke's Law. Specifically, if p is the
natural length of a section of spring, then the length of the
spring with tension T applied has length
s = ( 1 + T E ) p , ##EQU00001##
where E is a constant. In the catenary the value of T is variable,
but ratio remains valid at a local level, so
s p = 1 + T E . ##EQU00002##
[0032] The curve followed by an elastic spring can now be derived
following a similar method as for the inelastic spring.
[0033] The equations for tension of the spring are T cos
.phi.=T.sub.0, and T sin .phi.=.lamda..sub.0gp, from which
y x = tan .PHI. = .lamda. 0 p T 0 , T = T 0 2 + .lamda. 0 2 2 p 2 ,
##EQU00003##
where p is the natural length of the segment from c to r and
.lamda..sub.0 is the mass per unit length of the spring with no
tension and g is the acceleration of gravity. Write
a = T 0 .lamda. 0 so y x = tan .PHI. = p a , T = T 0 a a 2 + p 2 .
##EQU00004##
Then
[0034] x s = cos .PHI. = T 0 T and y s = sin .PHI. = .lamda. 0 p T
, ##EQU00005##
from which
x p = T 0 T s p = T 0 ( 1 T + 1 E ) = a a 2 + p 2 + T 0 E and
##EQU00006## y p = .lamda. 0 p T s p = T 0 p a ( 1 T + 1 E ) = p a
2 + p 2 + T 0 p Ea . ##EQU00006.2##
Integrating gives the parametric equations
x = a arcsinh ( p / a ) + T 0 E p + .alpha. , y = a 2 + p 2 + T 0 2
Ea p 2 + .beta. . ##EQU00007##
[0035] Again, the x and y-axes can be shifted so .alpha. and .beta.
can be taken to be 0. So
x = a arcsinh ( p / a ) + T 0 E p , y = a 2 + p 2 + T 0 2 Ea p 2
##EQU00008##
are parametric equations for the curve.
[0036] Chain under a general force: With no assumptions have been
made regarding the force G acting on the chain, the following
analysis can be made.
[0037] First, let T=T(s) be the force of tension as a function of
s. The chain is flexible so it can only exert a force parallel to
itself. Since tension is defined as the force that the chain exerts
on itself, T must be parallel to the chain. In other words, T=Tu,
where T is the magnitude of T and u is the unit tangent vector.
[0038] Second, let G=G(s) be the external force per unit length
acting on a small segment of a chain as a function of s. The forces
acting on the segment of the chain between s and s+.DELTA.s are the
force of tension T(s+.DELTA.s) at one end of the segment, the
nearly opposite force -T(s) at the other end, and the external
force acting on the segment which is approximately G.DELTA.s. These
forces must balance so T(s+.DELTA.s)-T(s)+G.DELTA.s.apprxeq.0.
Divide by .DELTA.s and take the limit as .DELTA.s.fwdarw.0 to
obtain
T s + G = 0. ##EQU00009##
These equations can be used as the starting point in the analysis
of a flexible chain acting under any external force. In the case of
the standard catenary, G=(0, -.lamda.g) where the chain has mass
.lamda. per unit length and g is the acceleration of gravity.
[0039] In the present invention, each catenary can have or exhibit
a linear path connected at two fixed points on the pair of radially
adjacent members. In this case, the catenary is not curved, but its
elasticity transmits the tension forces along the stretched path
parallel to the catenary. Exactly as found mathematically above.
Interestingly, the elastic or curved catenary system is an ideal
structure for affixing to a three dimensional surface like a sphere
or any convex shape as it conforms elegantly about the curvature.
Ideally, the curved catenaries have a smaller hang at the origin
and increase in hang at the radial extremes. This allows for the
increased expansion outward of the convexity prior to tensioning
the mesh system. When affixed or anchored to the tissue, the radial
members and catenaries can be tensioned and the tension will be
parallel to the member's path and redirected along attached
catenaries.
[0040] Biologic systems have a component of load bearing and
tensional integrity or tensegrity. Many static structures designed
to repair or replace biologic structures are purely load bearing in
nature and therefore destined to fail as they cannot replicate the
varying tensions the abdominal wall cycles through thousands of
time daily. For example, the Law of Laplace predicts abdominal wall
tension is a dependent variable of abdominal wall radius. The
radius of the abdomen varies many times daily with breathing,
coughing, and locomotion resulting in varying abdominal wall
tensions. In fact, it has been reported that the ventral abdominal
fascia elongates up to 150% of resting length during exercise. As
such, the ventral abdominal wall cannot therefore be treated as a
static structure in which a defect can be repaired with a static
mesh.
[0041] Tissue incompatibility results from the lack of
incorporation into adjacent tissues of current prostheses. Since
the prosthesis cannot be incorporated, a foreign body reaction
results and leads to encapsulation by fibrous tissue as the body
attempts to sequester the foreign material. While fibrous tissue
effectively separates and hides the tissue, the inter-fragmentary
strain of dissimilar tissues results in chronic irritation, fibrous
proliferation and sustained inflammation. Under this biologic
strain, the capsule in turn can harbor bacteria resulting in
chronic infections and inflammatory response.
[0042] Biometric analysis of abdominal wall defects currently
documents the defect in 2-dimensions, chiefly with imaging and
physical exam. The shortcoming does not take into account
differential abdominal wall tensions that vary between the separate
anatomic zones of the abdominal wall. For instance, none of the
current models recognize that the lower abdomen generates greater
tension in comparison with the upper abdomen. Taking into
consideration differential abdominal wall tensions, extant
technologies can potentially integrate anatomic distinctions of
individual patients and offer insight into biomechanics thus
permitting the design of customized meshes from basic stock
designs.
[0043] Current hernia meshes are non-customized prosthetic devices.
The present invention allows a customized prosthesis to be
fabricated based on biometric analysis of the subject.
[0044] Anchor point failures are a common cause for hernia
failures. Most anchoring techniques in open hernia failure rely on
horizontally applied sutures which necessarily cause tissue
strangulation and ischemia. The ischemic tissue results in
loosening of the anchoring sutures and failure of the fixation
point. The current mesh design may be anchored using traditional
suture techniques or even more advanced fixation techniques.
[0045] Meshes composed of acellular dermal matrix (ADM) are
purported to result in tissue regeneration but suffer rapid decline
of tensile strength which fails to account for efficacy in
herniorrhaphy. Furthermore, ADMs probably do not undergo the degree
of tissue incorporation and neo-vascularization envisioned by
manufacturers/vendors.
[0046] As shown in FIGS. 1-7, the proposed mesh 10 is engineered
with intrinsic elastomeric properties and comprised of a system of
catenaries 20 and trusses or radial members 30, that might be
additive, channeled, cast, printed, corrugated, embossed, extruded,
die cut, welded, laser etched, laser modified, mimetic in origin,
biodynamic, and incorporate random and preferred surface
orientation and roughness intended to actuate and amplify defined
stresses within a range of tensile and compressive forces that are
known to be structurally stable in tension and yet sufficiently
pliable for deployment and integration of biologic tissues;
particularly those of the abdominal wall. Biometric mesh 10 further
has a central region or opening 12 from which the radial members 30
extend outwardly to ends defining an outer perimeter 14. The
arrangement of components serves to distribute tension across the
hernia defect as well as to dissipate dynamic forces to the
anchoring points 40. The addition of struts 50, shown in FIGS. 2-4,
to select areas of the mesh 10 can adjust the tensile properties of
the prostheses to better accommodate the native tensile properties
of the implant site. The mesh 10 can be composed of separate and
numerous layers that are connected and juxtaposed to inhibit strain
and protect the structural integrity, as shown in FIG. 5. In
preferred embodiment, forces will be redirected from lateral
tension into rostral-caudal alignment to direct reconstitution and
normalize anatomical repair of the linea alba,
[0047] Elastomeric properties of the mesh 10 can be engineered into
the mesh 10 as result of weaving static monofilament materials in a
three-ply configuration. Use of monofilament materials reduce the
interstices available for seeding with bacterial contaminants.
[0048] Intrinsic cell instruction properties can be engineered into
the mesh fibers using laser etching. The cell instruction
properties of the mesh promotes incorporation of the prostheses
into surrounding tissues by promoting tissue ingrowth.
[0049] Metal salts incorporated into the mesh fiber act as
competitive inhibitors to mediators of inflammatory response. These
could include titanium dioxide as a competitive inhibitor of
metalloprotease mediators of the inflammatory response (Spyros AS,
2013).
[0050] In one instance, the proposed mesh 10 is conditioned with
autologous mesenchymal stem cells (MSCs) derived from processed
adipose tissue, and consistent with the stromal vascular fraction
(SVF).
[0051] The mesh 10 is preferably conditioned with the MSCs in a
bioreactor in advance of insertion into the hernia defect. It is
well known in the art that matrix coating enhances cell attachment,
stimulates differentiate, and accentuates force transduction in
alignment of the cell orientation. The biosynthetic composite
structure can be customized to the subject and accelerates
incorporation into adjacent tissues. It is envisioned that the mesh
10 will ultimately be incorporated by organized tissue aligned and
modeled with the tensile forces that the mesh is continually
subject to. Conditioning of the mesh 10 with MSC will reduce
fibrosis and potentially decrease bowel interactions such as
adhesions.
[0052] The mesh 10 can be manufactured using a 3-D printing
technology and can therefore be made on demand and to precisely
match the hernia defect in the subject based on non-invasive
measurements including physical exam.
[0053] In addition to a process of additive fabrication
(3D-Printing), it is also conceivable that a broad platform of
uniform isotropic distributed struts and trusses would be printed,
laser cut, die cut, embossed, sprayed on suitable differential
electrodes to align charge, or other means with these as
example.
[0054] The struts 50 might also be over sprayed with collagen,
PGLA, PCL, Poly-imides, or other bio-absorbable polymers known in
the art.
[0055] Among other defined structures, the mesh 10 emulates
zoomorphic design, specifically that of a spider web, and is
intended to possess an open architecture thus reducing infection
and inflammation. In this manner a reduced-mass mesh 10 results.
The stress/elongation characteristics of woven spider silk are
particularly well suited to accommodating the cyclical load bearing
properties of the ventral abdominal wall. Small pore size is
associated with increased rates of infection. The interstices of
the proposed mesh are smaller than 12 mm or less than the minimal
reported size for a Richter's hernia.
[0056] Still other biomimetic designs would include those
elaborated in cross section of woody stems, of plant branching
interfaces, demonstrating regular and randominzed cells, fibonacci
and ordered arrays, varying diameters and regular, ordered arrays
of inner cells that impart structural tension to lateral distortion
without imposing material stiffness.
[0057] Other potential elaborations of the design might be defined
as mathematical roulette curves of the variety technically known as
hypotrochoids and epitrochoids (similar to spirograph;
images/figures at the end. Example of such alternative designs are
found in FIGS. 2-4.
[0058] As shown in FIG. 1, some of the catenaries 20 may be formed
as shelves 20S or trays 20 with surface undulations, mimetic
grooves, instructive and resonant surface effects can be
incorporated into the mesh 10 at regular intervals in order to
provide a purchase for MSCs and to serve as an initial nidus from
where proliferation can occur to seed the entirety of the mesh 10.
It is not believed that a confluence of cell matrix is necessary
prior to implantation, and disclose that the wound milieu,
including growth factors, stem cells, cytokines, and inflammatory
priming are all possible events. Accentuating the potential to
define matrix deposition as an adjunct resonating dynamic
integration of loading bears the dividend of design.
[0059] The tensile strength of the mesh fibers is preferably
between 50 and 150 N/m, preferably about 100 N/m. The maximum
tension generated across the abdominal wall is reported to be 32
N/m
[0060] Fiber diameter is 0.2 mm or greater, typically about 0.26
mm.
[0061] Young's modulus of component fibers is anticipated to be 34
GPa.
[0062] Suture pull out strength is at least 5.5 kg at the periphery
or perimeter 14 of the mesh 10 at the anchor points 40.
[0063] As shown in FIG. 6, the dynamic mesh 10 is shown overlying a
convex surface 3 replicating an abdomen having a typical rounded or
domed curvature. As shown, the mesh 10 will conform easily to this
surface, and does so with little or no effort due to its compliant
nature. This is not possible with woven screen like mesh.
[0064] In FIGS. 7A and 7B, an alternative mesh 10 is shown. The
mesh 10 is ideally suited to support a patient's 2 breast 4 by
being affixed to the lower portion of the tissue. As shown, the
mesh 10 is made having half the structure of a hernia mesh 10,
preferably the lower portion or lower hemisphere. Alternatively,
this construct can be achieved by folding the mesh 10 of any of the
previous figures to create a double layer of mesh.
[0065] The mesh 10 is best applied to reconstruct the inferior, or
lower, pole of the breast 4. In this position, it can support an
implant or native breast tissue thus opposing gravitational descent
of an implant or breast tissue. When the implant 10 is placed in
the sub-pectoral plane, as is popular in breast reconstruction or
augmentation, the tensegrity structure allows the implant 10 to
migrate with activation of the pectoralis muscle 8 but the implant
10 would "spring" back when the pectoralis 8 is relaxed.
[0066] Variations in the present invention are possible in light of
the description of it provided herein. While certain representative
embodiments and details have been shown for the purpose of
illustrating the subject invention, it will be apparent to those
skilled in this art that various changes and modifications can be
made therein without departing from the scope of the subject
invention. It is, therefore, to be understood that changes can be
made in the particular embodiments described, which will be within
the full intended scope of the invention as defined by the
following appended claims.
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