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58
S. B. Orenstein
process is mostly benecial, excessive brosis can be a detriment, with resultant
encapsulation, mesh shrinkage, increased stiffness, and undesirable symptoms for
the patient [5]. Conversely, insufcient cellular ingrowth and brosis can lead to
poor mesh integration, mesh folding, central mesh failure, and ensuing hernia recurrence. This chapter will review commonly used meshes and their various characteristics, including material, density, and porosity, among other attributes that contribute
to incorporation of the mesh upon implantation.
Synthetic Mesh Characteristics (Table5.1 )
Most prosthetic materials, although chemically inert, generate an intense host
inammatory reaction upon implantation. The host response to implanted prosthetic
biomaterials follows a typical sequence of events, namely, coagulation, inammation, neovascularization, broplasia, matrix deposition, and wound contraction.
Exaggerated inammatory responses with its downstream effects can lead to signicant clinical sequelae, including excessive brosis and persistent foreign body
response. In the long term, such acquired rigidity of implanted meshes can contribute to changes in compliance of both the hernia site and the entire abdominal wall.
Clinically, this decrease in compliance can lead to a sensation of stiffness and result
in both physical discomfort and limitations in the activities of daily living for some
patients. The deleterious foreign body effects of synthetic meshes are related to the
amount of foreign body implanted. As a result, a goal of modern mesh manufacturers has been the development of prosthetic implants that are able to meet the tensile
demands of the abdominal wall while limiting the foreign body burden at the site of
the repair. As a theme of modern meshes, a reduction of the overall density/weight
of the mesh implant has been shown to be associated with an increase in biocompatibility of the prosthetic [5].
Material
Polypropylene (PP) remains the most commonly utilized polymer of hernia
meshes, and is manufactured by most companies that produce surgical meshes,
even if they manufacture other materials. It has the longest track record of any
mesh material, being used for over 60years, and has demonstrated long-term durability. Polypropylene remains popular due to its high tensile strength, durability,
pliability, and ease of use at time of repair. However, traditional (heavyweight)
polypropylene can induce a strong inammatory reaction. Excessive inammation
can lead to high levels of brosis, loss of pliability, chronic pain, as well as intolerance to infection. Modern lightweight polypropylene meshes obviate many of
these drawbacks, with reduced inammation and its sequelae (discussed below).
Also, if exposed to viscera, uncoated polypropylene can lead to signicant adhesive disease and/or stulae.
5 Permanent Prosthetics: Polypropylene, Polyester, ePTFE, andHybrid Mesh
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Table 5.1 Synthetic mesh characteristics
Material
Standard Permanent meshes
Polypropylene (PP) Surgipro™ US Surgical/
Polyester (PET) Parietex™ US Surgical/
Polytetrauoroethylene
(PTFE)
Polyvinylidene uoride
(PVDF)
Mesh product Manufacturer
Mesh characteristics
Heavyweight—110g/m
Covidien/
Microporous—0.6–0.8mm
Medtronic
Prolene™ Ethicon Heavyweight—105g/m
Microporous—0.8+ mm
Prolene Soft™ Ethicon Lightweight—45g/m
Macroporous—2.4mm
Marlex CR Bard Heavyweight—95g/m
Microporous—0.5mm
Bard Mesh™ Bard-Davol Heavyweight—95g/m
Microporous—0.46mm
Bard Soft
Mesh™
®
Trelex
Bard-Davol Lightweight—44g/m
Macroporous—2.5mm
Boston
Scientic
Heavyweight—95g/m
Microporous—0.6mm
ProLite™ Atrium Medium weight—85g/m
Microporous—0.8mm
ProLite Ultra™ Atrium Medium weight—50g/m
Microporous—0.75mm
Parietene™ Covidien/
Medtronic
Parietene™
Macroporous
DynaMesh
Covidien/
Medtronic
®
-PP
DynaMesh Medium weight—72g/m
standard
DynaMesh
®
-PP
DynaMesh Ultralightweight—36g/m
light
Medium weight—78g/m
Microporous—1.0–1.6mm
Medium weight—46g/m
Microporous—2.0–2.4mm
Macroporous—1.4–1.8mm
Macroporous—1.6–2.6mm
3-D multilament PET mesh
Covidien/
Medtronic
Medium weight—78g/m
Macroporous—1.0–1.6mm
Mersilene Ethicon 2-D multilament PET mesh
Lightweight—33–40g/m
Macroporous—1.0mm
Parietex™
Lightweight
Covidien/
Medtronic
Monolament PET mesh
Medium weight—46g/m
Macroporous—1.5mm
Versatex™ Medtronic Monolament PET mesh
Medium weight—64g/m
Macroporous—2.1–3.0mm
Innit WL Gore Medium weight—65–70g/m
Macroporous—unknown mm
DynaMesh
®
DynaMesh Density—unknown
Porosity—unknown
59
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
a
a
a
(continued)
60
Table 5.1 (continued)
S. B. Orenstein
Material
Mesh product Manufacturer
Partially resorbable composite meshes
Polypropylene with
Ultrapro™ Ethicon Ultralightweight—28g/m
poliglecaprone
Polypropylene with
Vypro II Ethicon Lightweight—35
polyglactin
Polyester with polylactic
ProGrip™ Covidien/
acid (PLA) microgrips
Polyester with polylactic
acid (PLA) microgrips
ProGrip™
Laparoscopic
Anti-adhesion and coated composite meshes
Expanded
DualMesh
®
polytetrauoroethylene
(ePTFE)
Dulex™ Bard-Davol (solid laminar sheet)
Polypropylene mesh and
Composix E/X™Bard-Davol Heavyweight, microporous
ePTFE
Composix L/P™Bard-Davol Lightweight, macroporous
Ventralex™ Bard-Davol Patch designed for smaller
Polypropylene and
Sepramesh™ Bard-Davol Medium weight
polyglycolic acid (PGA)
mesh +
carboxymethylcellulosesodium hyaluronate-
Ventralex ST™ Bard-Davol Patch designed for smaller
polyethylene glycol
(CMC-HA-PEG) coating
Ventralight
ST™
Mesh characteristics
(~40g/m
2
out of package before
poliglecaprone resorption)
Macroporous—2.0–4.0mm
Macroporous—3.4mm
Monolament polyester with
Medtronic
PLA microgrips
Medium weight—38g/m
2
(73g/m
out of package before
PLA microgrip absorption)
Macroporous—1.1–1.7mm
Covidien/
Medtronic
Monolament polyester with
PLA microgrips
Medium weight—49g/m
2
(82g/m
out of package before
PLA microgrip absorption)
Macroporous—1.8mm
WL Gore (solid laminar sheet)
2-sided: micro- and
macroporous
2-sided: micro- and
macroporous
a
a
polypropylene (abdominal wall
surface) and microporous
ePTFE (anti-adhesion)
polypropylene (abdominal wall
surface) and microporous
ePTFE (anti-adhesion)
defects (e.g., umbilical, port site
hernias)
Weight/pore size—unknown
Macroporous polypropylene
Heavyweight—102g/m
Pore size—unknown
defects (e.g., umbilical, port site
hernias)
Weight/pore size—unknown
Bard-Davol Medium weight
Macroporous polypropylene
Weight/pore size—unknown
2
2
2
a
2
a
a
a
5 Permanent Prosthetics: Polypropylene, Polyester, ePTFE, andHybrid Mesh
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61
Table 5.1
Material
Polypropylene mesh +
poliglecaprone coating
Polypropylene and
polydioxanone (PDS)
(continued)
Mesh product Manufacturer
Physiomesh™ Ethicon Light or ultralightweight—
Mesh characteristics
(estimated 28–40g/m
2)a
Macroporous—unknown mm
Proceed™ Ethicon Lightweight—45g/m
2
Macroporous—unknown mm
a
a
mesh + oxidized
regenerated cellulose
(ORC) backing
Polypropylene mesh +
omega-3 fatty acid
coating
C-Qur™ Atrium Medium weight—85g/m
Microporous—0.8mm
C-Qur Lite™ Atrium Medium weight—50g/m
2
2
Microporous—0.75+ mm
3-D Polyester +
collagen-polyethylene
Parietex™
Composite
Covidien/
Medtronic
Medium weight—78g/m
Macroporous—1.8×1.5mm
2
glycol (PEG) coating
Monolament polyester
+ collagen lm
Polyvinylidene uoride
(PVDF)+polypropylene
Symbotex™
Composite
DynaMesh
IPOM
Medtronic Medium weight—66g/m
Macroporous—2.3–3.3mm
®
DynaMesh Medium/
heavyweight—60/108g/m
2
2
(PP-60/PP+PVDF 108 for
overall effective density of both
materials)
Macroporous—>1mm
Polypropylene + titanium
(vapor deposition of
titanium)
TiMesh™
strong
PFM Medical Medium weight—65g/m
Macroporous—>1mm
TiMesh™ light PFM Medical Ultralightweight—35g/m
2
2
Macroporous—>1mm
TiMesh™
extralight
PFM Medical Ultralightweight—16g/m
Macroporous—>1mm
2
Hybrid Meshes
®
Polyester + small
intestine submucosa
(SIS)
Zenapro
Cook Braided polyester backbone
with SIS laminate
Weight/pore size—unknown
a
PTFE + PGA:TMC Synecor WL Gore Monofilament PTFE
backbone with PGA:TMC 3D
matrix and PGA:TMC
anti-adhesion film
Weight/pore size—unknown
a
This table represents a summary of commonly utilized hernia meshes. Not every mesh manufactured has been included due to lack of information available, low utilization, etc. Some meshes
have been listed for reference that are currently not in use. Information was obtained from manufacturer material as well as published literature. Please note that there are discrepancies among
various published values, and manufacturer information was used as the primary source, when
available.
Weight/density units, g/m
a
Information not available at time of publication
2
. Pore size units, millimeters
62
S. B. Orenstein
Polyester (polyethylene terephthalate (PET)) is a hydrophilic polymer that, like
polypropylene, has a long track record of effectiveness for hernia repair. Traditional
polyester meshes are multilament, based on 2-dimensional (at) or 3-dimensional
constructs. Newer polyester-based meshes have switched to monolament polyester
bers with the overall goal of increasing biocompatibility. Traditional multilament
polyester meshes are noted to be highly pliable, allowing the surgeon to easily
manipulate and conform the mesh to variations of the abdominopelvic walls. Like
polypropylene, polyester can lead to signicant inammatory response with ensuing heavy brosis, visceral adhesions, and stulae.
Polytetrauoroethylene (PTFE) is a carbon- and uorine-based synthetic hydrophobic polymer. Most people associate PTFE with nonstick cookware (e.g., Teon).
PTFE has been made in two main forms for hernia repair, with most common application in a laminar sheet, or “expanded” PTFE form (ePTFE). However, knit berbased PTFE meshes have been developed as well. DualMesh (WL Gore, Newark,
DE, USA) is the most widely used solid laminar ePTFE mesh, containing a smooth
side as an anti-adhesion barrier and a corrugated side to facilitate ingrowth. ePTFE
use has diminished signicantly over the last several years, likely due to its lack of
resilience in the setting of infection as well as a signicant brotic and encapsulation response to it. A silver chlorhexidine-impregnated version has also been produced to help reduce infectability.
Polyvinylidene uoride (PVDF) is a polymer that, despite having been described
for well over a decade, [6] it’s use within the United States is very limited, with
greater utilization in Europe (DynaMesh, Aachen, Germany). One of the principal
described benets of PVDF is the ability to withstand hydrolysis and degradation
compared to other materials such as PP or PET, and additional studies have demonstrated reduced foreign body response to PVDF [6, 7].
Regarding the biologic study of mesh implants, although tissue reactions of
biomaterials vary greatly throughout the literature, experience in animal studies
demonstrates that polyester-based meshes are a signicant inducer of inammation and appear to induce a severe chronic foreign body reaction [5]. While polypropylene meshes also demonstrate signicant inammation and some degree of
foreign body response, the severity is strikingly less when compared to polyesterbased implants. Compared to the ber-based mesh constructs, integration of laminar ePTFE mesh within tissues was met more with heavy brosis and encapsulation
instead of integration. This has been seen in invivo studies and clinically with
excised samples of previously implanted ePTFE demonstrating signicant heavy
brosis. In addition, decreased ability for inter-mesh neovascularization may predispose ePTFE mesh to diminished biocompatibility. Heavy brosis and encapsulation often leads to mesh shrinkage. Overall, of the more commonly used
polymers, polypropylene exhibits the highest degree of tissue biocompatibility
followed by ePTFE and polyester. The clinical implications of these ndings are
not entirely clear, and no randomized controlled trials have evaluated these materials in a comparative fashion.
5 Permanent Prosthetics: Polypropylene, Polyester, ePTFE, andHybrid Mesh
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63
Weight/Density
Mesh density, most commonly termed “weight,” is an important determinant of
overall structural strength of the mesh. Typically measured in grams per meter
squared (g/m2), mesh weight/density is generally categorized as lightweight,
medium weight, and heavyweight, though other terms have been described (e.g.,
ultralightweight). While various density ranges have been described, commonly
published density/weight ranges include [8]:
Heavyweight—>90g/m
Medium weight—50–90g/m
Lightweight—35–50g/m
Ultralightweight—<35g/m
2
2
2
2
Studies have shown that traditional heavyweight meshes may have been overengineered, with Marlex-type meshes (heavyweight polypropylene) displaying 4–6
times the tensile and burst strength of the native abdominal wall [9]. Such heavyweight meshes induce a signicant inammatory reaction and ensure exaggerated
brotic response, leading to mesh contraction and excessive hardening of the mesh
and surrounding tissues which can lead to chronic pain symptoms [5]. This excessive
granulomatous reaction around the mesh bers led to the development of lighter, less
dense mesh, with a combination of smaller caliber bers and larger spaces (pores)
between the mesh bers (see “Porosity” section below) [9]. Such reductions in prosthetic weight result in reduced inammatory reaction, less brosis, and mesh contraction, as well as improved compliance and exibility. However, with all the fervor
of producing reduced-weight meshes, manufacturers may have swung the pendulum
too far and produced meshes too lightweight. Such lightweight meshes may result in
central mesh failure, whereby a mechanical failure develops within the mesh, resulting in fatigue fracture and subsequent hernia recurrence [10]. Therefore, caution
should be used with some lightweight meshes for ventral hernia repair, especially in
the setting of bridged repairs, and a heavier weight mesh should be considered.
The scientic and clinical evidence for the benets of mesh density is evolving.
Animal studies as well as clinical studies support the notion that limiting density/
weight results in marked reduction in foreign body response and overall biocompatibility [11]. A prospective randomized trial of inguinal hernia repair demonstrated
elevated inammatory markers and oxidative stress in the heavyweight mesh group
compared to lightweight implantations [12]. While other studies support the clinical
benets of lightweight mesh [13], a long-term study negated such ndings, with
equivalence seen at 2years post-TEP inguinal hernia repair [14]. Despite a variety
of studies, the majority of studies demonstrate that the implantation of lightweight
polypropylene mesh results in decreased chronic discomfort and reduced restriction
of physical activities while providing sufcient strength for the reinforcement of
hernia repairs.
64
S. B. Orenstein
Porosity
Along with reducing the ber thickness and density, allowing more empty space
between the mesh bers also aids in reducing the overall foreign body footprint of
the mesh. Following implantation, each mesh ber is surrounded by a granulomatous reaction, with some degree of inammation and brosis [5, 9]. Because microporous meshes typically contain thicker bers and limited interber spacing, such
heavyweight microporous meshes (e.g., Marlex) induce a signicant inammatory
and brotic response. The ensuing “bridging” brosis results in excessive scar plate
formation, mesh contraction, and loss of pliability [9]. Macroporous meshes, commonly with light or medium density, allow for reduced bridging brosis with less
mesh contraction. Also, larger pore size permits greater uid transport across the
mesh, theoretically reducing seroma formation. For perspective, heavyweight polypropylene (e.g., Marlex) is an example of a microporous mesh with a pore size of
0.6mm, compared to typical lightweight macroporous meshes commonly having
pore sizes in the 2–4mm range. Importantly, reduced weight macroporous monolament meshes demonstrate an important nding of greater tolerance in the setting
of some degree of contamination (Note: greater tolerance, not resistance, to contamination). Early data support the use of permanent lightweight macroporous
polypropylene meshes in contaminated settings, [15] though there is a lack of consensus for this among hernia surgeons.
Filament Design
Meshes are created using materials arranged in either multilament or, more commonly, monolament design. Multilament meshes, containing bundles of mesh
brils, are beneted by increased exibility at time of implantation. However, they
can induce heightened inammatory and foreign body reaction. Of more importance is the inability for multilament meshes to withstand contamination and
commonly require mesh explantation if infected [16]. This intolerance of multilament meshes to contamination is thought to be due to bacteria being trapped
between the small interstices of the mesh brils, with insufcient neovascularization and inability of immune cell access to such small spaces where the pathogens
reside [17]. Conversely, monolament meshes tend to be more stiff and rigid upon
implantation. However, they demonstrate reduced inammatory and foreign body
responses compared to their multilament counterparts, as well as having reduced
bacterial adherence [16]. And, while any mesh has the potential for infection and
need for mesh explantation, monolament (macroporous lightweight) meshes have
demonstrated greater tolerance in the setting of contamination, as discussed in the
previous section.
As already mentioned traditional polyester-based meshes such as Parietex
(Medtronic, Minneapolis, MN, USA) are composed of multilament bers.
However, newer polyester meshes have been designed with monolament bers,
including Versatex, Symbotex, and ProGrip (Medtronic), which are manufactured
5 Permanent Prosthetics: Polypropylene, Polyester, ePTFE, andHybrid Mesh
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65
with similar monolament polyester bers. The overall goal of monolament forms
is to increase biocompatibility upon implantation and perhaps increase tolerance to
contamination/infection and allow greater vascularity between mesh bers.
However, as Petro etal. point out, the use of monolament polyester meshes requires
some degree of caution, as central mesh failures and subsequent hernia recurrence
were seen with an unusually high rate with the use of a monolament polyesterbased mesh [10].
Anti-adhesion Barriers
Because of the inammatory response to foreign materials, the abdominal cavity
creates varying degrees of adhesions to implanted prosthetics. In an effort to reduce
adhesion formation, mesh manufacturers have developed composite meshes that
greatly reduce adhesions and allow intra-abdominal placement of meshes. Common
design strategies for intra-abdominal meshes include one side containing some form
of tissue-separating barrier designed to impede ingrowth of viscera and adhesions,
while the opposite side contains a porous, or a rougher, surface to facilitate ingrowth
from the peritoneum.
Various anti-adhesive polymers have been developed including hyaluronic
acid (Ventralight ST; Sepramesh, Bard-Davol), polyethylene glycol (Parietex,
Medtronic), collagen lm (Symbotex, Medtronic), oxidized regenerated cellulose (Proceed), omega-3 fatty acids (C-Qur, Atrium), and poliglecaprone
(Physiomesh, Ethicon), among others. These mesh coatings are intended to persist until the abdomen has created a neoperitoneum over the visceral side of the
mesh, typically within 10–14days after mesh implantation. Of note, the design
of Physiomesh (Ethicon, Somerville, NJ, USA) differed greatly from other
meshes for use within the abdominal cavity. Instead of only a single-sided coating of poliglecaprone (i.e., Monocryl), both sides contained the poliglecaprone
anti-adhesion barrier. This design aw impeded adequate ingrowth from the peritoneal side and was likely a contributing factor in reported failures and its eventual removal from the market.
ePTFE is very effective as an anti-adhesion barrier. A common use of ePTFE
(e.g., DualMesh, WL Gore, Flagstaff, AZ, USA) is as a bilaminar mesh, with fusion
of a “macroporous” rough/corrugated layer to promote tissue ingrowth from the
peritoneum, and a smooth “microporous” layer, which impedes adhesions on the
visceral surface. Similarly, other meshes have utilized ePTFE as an anti-adhesion
barrier, with bare polypropylene serving as the peritoneal, ingrowth side, while the
ePTFE impedes adhesions on the visceral size (e.g., Composix, Davol, Warwick,
RI, USA). One potential issue with such composite meshes is the differing rates of
brosis and contraction of the two completely different materials. ePTFE tends to
induce signicant brous encapsulation leading to greater shrinkage of this layer
compared to the polypropylene side. This may result in mesh curling and possible
exposure of polypropylene bers, leading to worse adhesions, or perhaps hernia
recurrence, and may require mesh explantation.
66
S. B. Orenstein
Composite andHybrid Meshes
Many of the meshes described above are composed entirely of permanent polymer
bers. However, there are varieties of permanent meshes that also contain resorbable or other materials. The addition of temporary bers adds initial structural integrity at time of implantation and then resorbs as tissue inltrates the mesh. One
commonly used example is Ultrapro (Ethicon, Somerville, NJ, USA), which is an
ultralightweight polypropylene mesh containing interwoven bers of poliglecaprone (i.e., Monocryl, Ethicon) that add initial stiffness to the mesh. Ultrapro starts
out at ~40g/m
tion of the poliglecaprone bers, hence the ultralightweight designation. Similarly,
Vypro (Ethicon, Somerville, NJ, USA) consists of both polypropylene bers and
polyglactin (i.e., Vicryl) to add initial strength which resorbs (~2–3months) following implantation. An example of a hybrid/composite mesh for intra-abdominal use
is Ventralight ST (Bard-Davol, Warwick, RI, USA), which is a barrier-coated
medium weight polypropylene mesh that also contains interwoven polyglycolic
acid (PGA) bers. The use of PGA bers allows temporary “thickness” of the mesh,
which facilitates adherence of the anti-adhesion hydrogel to the mesh bers. TiMesh
(PFM Medical, Nuremberg, Germany) is an interesting polypropylene-based mesh
with covalently bound titanium atoms around each mesh ber. The stated benets of
the titanium coating include a reduction in inammation and foreign body response,
thus improving biocompatibility as well as allowing for intra-abdominal use.
Newer laminate hybrid meshes have been developed that incorporate both a permanent mesh ber backbone combined with biologic or synthetic-based resorbable
components. While the literature is very limited for such products, early data demonstrate safety and efcacy [18]. Zenapro (Cook Medical, Bloomington, IN, USA) is a
laminate synthetic-biologic hybrid consisting of a lightweight macroporous polypropylene mesh with layered small intestine submucosa (SIS). The biologic SIS acts to
“shield” the polypropylene bers upon implantation, allowing for intra-abdominal
placement as well as limiting potential contamination of the permanent mesh bers.
Synecor (WL Gore) is another hybrid mesh that consists of three different materials:
a macroporous monolament PTFE mesh ber backbone surrounded by Gore’s
Bio-A resorbable synthetic polyglycolic acid and trimethylene carbonate (PGA/
TMA) matrix, with a PGA/TMA lm on one side to reduce visceral adhesions. The
Bio-A matrix facilitates ingrowth, lasting approximately 3–6months. At time of publication, there are no studies evaluating the use of Synecor.
2
out of the package but ends up ~28g/m2 following complete resorp-
Additional Mesh Considerations
Self-Fixating Mesh
One of the challenges of mesh placement during hernia repair is mesh xation.
There are multiple methods and devices utilized to xate the mesh area of concern,
with sutures and tacks being the most prevalent xation sources. Such xation
5 Permanent Prosthetics: Polypropylene, Polyester, ePTFE, andHybrid Mesh
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67
methods have the potential drawbacks of increased pain, bleeding, as well as chronic
foreign body and granulomatous reactions. In an effort to reduce xation-related
complications, manufacturers have developed meshes that utilize a built-in form of
xation. The most widely used self-xating mesh, ProGrip (Medtronic, Minneapolis,
MN, USA), utilizes monolament polyester-based mesh that is covered with numerous absorbable polylactic acid (PLA) micro-hooks, akin to a burr found in nature.
The microscopic hooks promote adherence to the surrounding tissue upon implantation and then absorb over ~18months as the mesh allows ingrowth for long-term
xation. Much literature on ProGrip has been published, with over 40 studies over
the last 8years, mostly involving inguinal hernia repair. While several case series
are supportive of the efcacy of ProGrip with potential for reduced pain, several
randomized studies and a recent meta-analysis are not as supportive [19–21]. The
higher-level data point to the principal advantage of self-xating mesh as reduced
operative time and found equivalence of pain with traditional inguinal hernia repair
methods. One randomized controlled trial (RCT) found a signicantly higher recurrence rate with the use of ProGrip for open inguinal hernia repair [20]. Very little
data exist for self-xating mesh and ventral hernia repair, and no RCTs have been
published. Other self-gripping and self-adhering meshes are actively being
researched and have been developed with early use in various parts of the world.
Though, there is limited access to other self-adhering meshes in the Unites States at
this time.
Anisotropy
Various material properties of meshes contribute to the overall mechanical behavior of
the repair of hernias. While the differing elasticity of meshes when pulled in different
directions (i.e., anisotropy) has not been well dened to date, studies have shown that
many commonly used meshes have up to 20-fold differences in their “stretchability”
when pulled in perpendicular directions [22]. This may factor into the success of
abdominal wall repairs, as the native abdominal wall is roughly twice as elastic in the
vertical (craniocaudal) axis versus the transverse/horizontal axis. As a result, mesh
implantation may need to be strategic in order to address the differences in both the
textile properties of the prosthetic and the physiologic properties of the abdominal
wall [22, 23]. Interestingly, mesh labeling or descriptions of anisotropic behavior
from manufacturers are lacking for nearly all products on the market today.
Conclusion
Surgical meshes have demonstrated their usefulness for hernia repair over many
decades, with signicant reductions in hernia recurrence upon implantation. A
variety of permanent synthetic surgical mesh prosthetics have been developed,
which offer immediate structural support as well as provide a scaffold for
ingrowth, thus facilitating long-term integration with the body at the site of her-
nia repair. Many mesh products have been produced over the years, with poly-
propylene, polyester, and ePTFE being the most common materials utilized for
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