Polypropylene mesh for hernia repair

Polypropylene mesh or surgical mesh is a product made of polymeric yarn, which is used for hernia repair. Polypropylene meshes are designed in different sizes; one of the most widely used sizes is 6*11 cm.

First, we will talk briefly about hernia disease, its types and causes, and then we will learn more about surgical meshes.

What is a hernia?

A hernia is a lesion in the wall of the organs that occurs when an internal organ protrudes through its muscle wall, usually in the abdomen. The weakening or tearing in these walls with age or pressure causes damage to the tissue and the hernia formation.

A hernia can be external and visible under your skin or internal and non-visible. Their sizes can vary from very small to very large. Sometimes, a hernia can be a painless protrusion, or it can be painful, especially during physical activities.

Types of hernias

The most common types of hernias are:

• Inguinal hernia occurs when fatty tissue or a part of the intestine pushes in the groin.
• Femoral hernia happens at the top of the groin from the side of the muscles to the skin’s surface. They are much less common than inguinal hernias.
• Incisional hernia occurs at the surgical incision site, mainly in the abdomen.
• Abdominal hernia occurs in the general wall of the abdomen.
• Umbilical hernia occurs around the navel and happens when fatty tissue or a section of the intestine pushes near the navel (belly button).
• Hiatal hernia occurs inside the abdomen along the upper part of the abdomen (diaphragm wall).

Inguinal hernia is the most common type of hernia. According to the size of Polypropylene mesh used in this type of hernia, which is 11*6 cm, the most widely used size of polypropylene mesh will be this size.

Also, there is a type of Polypropylene mesh (6 * 13.5 cm) with grooves in the middle that are designed for both sides of the inguinal cord and is also used for inguinal hernia. This type of polypropylene mesh is also known as Lichtenstein mesh.

Causes of hernia

If there is a weakness in the wall of an organ and pressure is applied from inside that organ to the wall, the wall will gradually open, and the viscera will be placed inside the lesion and even pass through it.

The hernia can be present from birth. However, it often occurs in old age. Studies results suggest elevated intra-abdominal pressure in patients or those with normal diaphragm tissue cause hernia.

The main causes of muscle weakness that can lead to a hernia include:

• Aging
• Pregnancy
• Lifting heavy weights
• Strenuous exercise
• Constant coughing or sneezing
• Overweight and obesity
• Poor nutrition
• Excessive pressure
• …

What is polypropylene mesh?

Polypropylene mesh is a valuable material used to repair abdominal wall defects, especially hernias. This product has a net-like texture and is made of non-absorbable biocompatible polymers, absorbable materials, or a combination of both. So surgeons, according to the location of the lesion, select the suitable model.

What materials surgical mesh made of?

In the past, the surgical mesh was produced from polyester threads and sold under Mersilene, which had high flexibility and moderate strength. Over time, monofilament yarns made from pure medical grade polypropylene called prolene mesh replaced polyester yarns (Mersilene).

Prolene mesh is more compatible with the body and shows the slightest tissue sensitivity. On the other hand, polypropylene is more chemical resistant and has more durability and strength than Mersilene against the chemical compounds of blood and secretions.

Dual meshes to reduce adhesion

In some cases, the hernia is in contact with the abdominal viscera, and there is a high possibility of adhesion between the internal organs, especially the wall, after hernia repair.

To avoid this problem, we can use dual mesh. Indeed, a layer of non-stick material (Barrier) is added to one side of the Polypropylene mesh to prevent sticking internal organs. This type of mesh is known as dual-layer surgical mesh (Dual Mesh), and the protective layer is mainly made of medical-grade silicone or PTFE (medical Teflon).

Polypropylene mesh structure

As mentioned, prolene meshes are porous woven monofilaments used for hernia repair. According to the hernia’s location, the strength and type of mesh is very important.

The surgical mesh is woven from many threads by a particular type of weaving machine so that all the threads are interwoven and create a uniform texture. This design makes it so that if there is an injury, a hole or a lesion in the tissue, it will not spread to the other parts of the tissue, and other parts will maintain their strength and shape.

On the other hand, since the prolene meshes are in contact with the connective tissue, they should be soft and flexible. Mersiliene meshes have high flexibility due to the multifilament yarn. However, the monofilament structure makes prolene meshes (polypropylene meshes) harder due.

In addition to the strength of the prolene mesh, the pore size is also important. If these pores are too small, they cause bacterial colonies and infection. Therefore, the mesh pores should be large enough to create significant flexibility and reduce the risk of infection.

Therefore, a high number of thread strands, high flexibility, less density, a smaller thread diameter, and smaller Polypropylene mesh thickness cause higher quality.

Polypropylene mesh advantages

According to those mentioned above, among the available surgical meshes, prolene meshes (polypropylene meshes) are the most commonly used. Among the advantages of prolene mesh, the following can be mentioned:

• Usable for most hernia repair surgeries
• Compatible with tissues and low infection risk
• High resistance to chemical compounds of blood and tissue secretions
• Variety of textures
• Durability
• Comfortable for patient

Different sizes of prolene meshes (polypropylene meshes)

Due to the presence of a hernia in different organs and different sizes of the hernia, prolene meshes are produced in various sizes so that each size can be used in its own case.

In general, the most sizes produced by companies are:

• 6cm * 11cm
• 7.5 cm * 15 cm
• 6cm * 13.5cm
• 10cm * 15cm
• 15cm * 15cm
• 30cm * 30cm

Different companies also produce other sizes according to the customer’s needs.

The importance of selecting the right size of polypropylene mesh

The variety sizes of prolene meshes are due to their structure. The structure of Polypropylene mesh consists of a large number of threads. Therefore, cutting mesh in the surgical environment should be avoided.

Cutting the polypropylene mesh causes many threads to be separated from the mesh texture and spread in the surgical site. The presence of a large number of threads in the surgical site may be dangerous because they act as a foreign body and cause inflammation and sensitivity in the tissues.

It is recommended to use the right sizes, and if there is a requirement to change the size and cut prolene mesh, be sure to cut it away from the surgical environment, adjust the size, and wash the mesh with a serum to remove the cut threads. Finally, bring the mesh with the adjusted size to the surgical environment.

How to use polypropylene Mesh

• First, based on the surgical site and the size of the lesion, the right size of the surgical mesh is determined by the surgeon.
• After opening the surgical site and repairing tissue, the polypropylene mesh is opened on the surgical table, and after washing with physiological serum, it is given to the surgeon.
• Then, the surgeon places the surgical mesh on the lesion, and covers the lesion entirely.
• Then, to fix the prolene mesh on the surface, a suture, which is usually a polypropylene thread, is used. Depending on the mesh’s location and the surgeon’s discretion, the suture is connected individually to the underlying tissue at different distances.
• Other sutures, such as nylon or absorbable sutures, may be used to fix Polypropylene mesh at the surgeon’s discretion.
• Also, metal sutures (staplers) called Tacker are used in laparoscopic hernia repair surgeries that are difficult to access and suture.