2. DEFINITION…
Surgical mesh is a sterile woven piece of netting that is used in surgical
procedures to help repair sites of surgical incision, tissue herniation, or to
provide support to internal parts of the body.
Surgical mesh is used in many different types of surgical procedures. Hernia
repair is one of the most frequently performed general surgeries world wide,
and usually involves the use of surgical mesh. Mesh is also used to assist in
surgical correction of urinary incontinence, uterine suspension, vertebral
reconstruction, tissue reconstruction, vaginal prolapse, etc.
In tissue repair application, the mesh serves to mechanically strengthen the
weakened area while simultaneously promoting long term stability by acting as
a scaffold for new tissue growth.
3. Indication…
Surgical mesh can be permanently implanted to reinforce the
vaginal wall for POP repair, or support the urethra or bladder
neck for the repair of SUI.
In pelvic organ prolapse , the pelvic organ may shift downwards
and bulge out of the vagina. This occurs in women whose pelvic
floor muscles and tissue are too weak to hold the organs in
place.
Stress urinary incontinence (SUI) is a leakage of urine during
moments of physical activity that increases abdominal pressure,
such as coughing, sneezing, laughing, or exercise. SUI is the
most common type of urinary incontinence in women.
Biodegradable surgical mesh are used in the treatment of
hernias where the connective tissue has ruptured or
4. The use of surgical mesh slings to treat SUI provides a less
invasive approach than non-mesh repairs, which require a larger
incision in the abdominal wall. The multi-incision sling
procedure can be performed using three incisions, in two ways:
with one vaginal incision and two lower abdominal incisions,
called retropubic; or with one vaginal incision and two
groin/thigh incisions, called transobturator . There is also a
"mini-sling" procedure that utilizes a shorter piece of surgical
mesh, which may be done with only one incision.
5. Materials used for surgical mesh include:
Non-absorbable synthetic polymers :
1. Polyprophylene(Prolene).
• The mesh is pliable but at the same time sufficiently mechanically resistant.
• Fully transparent to allow secure fixation.
• Monofilament.
• Can be used in presence of infection.
• Good elasticity and high tensile strength.
• Non absorbable.
• Used for hernia repair and abdominal wall construction.
• Sterilized by gamma radiation.
• Fixed with prolene sutures.
.
6. 3. PTFE (Teflon/Gordex)
• Soft, flexible non absorbable.
• Impervious to fluids.
• Should not be used in presence of infection.
4.Stainless steel mesh
• Rigid and difficult to work with it.
• Causes discomfort to patient
Absorbable synthetic polymers:
-Polyglycolic acid; used for wound closure and organ support.
Biological Mesh:
- Surgisis ( Porcine submucosa)
-Alloderm (Cadaveric human dermis)
Composite mesh:
-A combination of any of 3 previous materials.
Biological
Mesh
7.
8. Physical or mechanical properties of mesh materials…
Weight- Measurement of the “heaviness” or “heft” of the material,
weight /unit area.
Shrinkage-Dimensional decrease in length or width of a material.
Strain- Deformation of a material in response to an applied force,
force/unit area.
Tensile strength-Maximum stress that a material subject to a
stretching load can withstand without tearing or breaking.
Burst strength-The maximum uniformly distributed pressure applied
at right angle to its surface that a material will withstand under
standardized conditions pressure/unit area
Elasticity - Property of a material whereby it changes its shape and
size under the action of opposing forces, but recovers its original
configuration when the forces are removed.
9. Stiffness-Ratio of steadily increasing or decreasing force acting
on a deformable elastic material to the resulting displacement
or deformation.
Isotropy-When a material do not exhibit differences in
properties based on the direction of the applied load, the
material is said to be isotropic.
MonofilamentTypes of
mesh
10. Ideal properties of surgical mesh…
Ideal properties of synthetic biomaterials have been
established in the 50´s of the last century, the material
should ideally be:
- Physically stable after implantation
- Chemically inert
- Non allergic
- Non carcinogenic
- Mechanically resistant
- Sterilizable
- Cheap
11. Properties of the surgical meshes
Relative Weight of Meshes
Shrinkage
Porosity, Bridging
Elasticity of Abdominal Wall and Mesh
Elasticity
Stability of Mesh.
12. Complications of meshes …
Chronic pain.
Tissue or mesh erosion into organs.
Most complications are merely a reflection of the properties already
described.
Thus, when choosing a mesh, the surgeon must decide which properties
are the most important for the specific situation.
For example, materials such as ePTFE have a good profile for adhesion risk
but a high risk of infection.
Incontrast, Polypropylene meshes are durable and have a low infection
risk but they have little flexibility and a high adhesion risk.
Bowel obstruction.
Mesh degradation.
13. INFECTION RISK
The risk of infection is mainly determined by the type of
filament used and pore size.
Microporous meshes (for example, ePTFE) are at higher
risk of infection because macrophages and neutrophils
are unable to enter small pores (< 10 μm). This allows
bacteria (< 1 μm) to survive unchallenged within the
pores. A similar problem applies to multifilament
meshes.
The meshes at lowest risk of infection are, therefore,
those made with monofilament and containing pores
greater than 75 μm. Eradication of infection in such
meshes can be achieved without their removal.