Hernia mesh is a medical device used in the majority of hernia repair operations to reinforce the weakened tissue of the abdominal wall. Mesh provides a scaffold for the body’s natural tissue to grow into, strengthening the repair. The use of mesh has become the standard of care for most hernia procedures, including inguinal and ventral hernias, due to its effectiveness in lowering recurrence rates compared to repairs using only sutures. This prosthetic material acts as a supportive patch, allowing for a tension-free repair tailored to the specific demands of each surgical case.
Primary Material Classifications
The foundational composition of a hernia mesh determines its long-term interaction with the body. Most meshes fall into three broad categories based on their raw material. Synthetic meshes are the most common, typically made from non-absorbable polymers like polypropylene, polyester, or expanded polytetrafluoroethylene (ePTFE). Polypropylene is widely used because it promotes tissue ingrowth, securing the mesh permanently to the abdominal wall.
Composite meshes combine different materials to achieve a balance of properties. They often feature a non-absorbable layer for strength and a separate layer to minimize adhesion to internal organs. These layered meshes are commonly used when the implant must be placed in direct contact with the intestines. The anti-adhesive barrier may be made of a resorbable material that protects the organs during the initial healing phase.
Biological meshes are derived from processed animal tissue, such as porcine dermis, or human donor tissue. These materials are completely absorbed by the body over time, relying on the host’s tissue regeneration for the final repair strength. Biological meshes are highly biocompatible. They are generally reserved for contaminated or infected surgical fields where a permanent synthetic mesh would carry a high risk of infection.
Defining Mesh by Structure and Weight
The physical construction of the mesh fabric significantly influences its performance and the patient’s long-term comfort. Meshes are defined by their weight, which correlates with the density of the material used. Heavyweight meshes (over 70 g/m²) use thicker filaments and a tight weave, resulting in high tensile strength and a pronounced foreign body reaction. Lightweight meshes (typically less than 60 g/m²) feature thinner filaments and a more open structure. This reduced material mass results in greater flexibility and a lower risk of chronic pain or abdominal wall stiffness.
The pore size of the mesh is a structural factor independent of the raw material. Macro-porous meshes have pores larger than one millimeter, which facilitates the ingrowth of cells and promotes effective tissue integration. Conversely, micro-porous meshes have smaller pores. These smaller pores can lead to a more intense fibrotic reaction and the formation of a stiff scar plate that may not integrate well with the surrounding tissue.
Permanent Versus Absorbable Options
The timeline of the mesh’s function within the body separates permanent from absorbable options. Non-absorbable meshes are designed to remain in the body indefinitely, providing lifelong mechanical reinforcement to the repaired area. Materials like polypropylene or ePTFE serve as a permanent structural bridge, dramatically lowering the chance of hernia recurrence.
Absorbable meshes are temporary support structures that are broken down and resorbed by the body over a period of weeks to months. These materials, such as synthetic polymers or biological tissues, provide initial strength. They encourage the body’s native tissue to grow and form a strong, permanent scar. The final strength of the repair depends completely on the quality of the new tissue that forms in place of the dissolved mesh.
Partially absorbable meshes, also known as hybrid meshes, combine permanent and temporary filaments. The absorbable components dissolve, leaving behind a permanent, lightweight mesh structure with very large pores. This strategy aims to provide long-term reinforcement while minimizing the amount of foreign material left in the body. Minimizing foreign material can improve flexibility and reduce the risk of discomfort.
Factors Influencing Mesh Selection
A surgeon’s choice of mesh involves balancing the repair’s necessary strength with patient comfort and tissue integration. The specific type of hernia, such as inguinal, ventral, or hiatal, dictates the required material properties and placement location. For instance, a small inguinal hernia in a healthy patient may be suited for a lightweight, permanent polypropylene mesh. This ensures long-term durability with minimal foreign body sensation.
The patient’s health status, including factors like obesity, diabetes, or a history of infection, heavily influences the risk profile of the procedure. In cases involving a contaminated surgical field or a high risk of infection, a surgeon may elect to use a biological or fully absorbable mesh. This avoids complications associated with a permanent synthetic implant in that environment. The anticipated strength of the abdominal wall also plays a part in selection.
The surgical approach, whether open or minimally invasive (laparoscopic or robotic), dictates the mesh dimensions and handling characteristics. A strong, heavyweight mesh may be chosen for a large or recurrent ventral hernia to maximize reinforcement against high intra-abdominal pressure. Conversely, for repairs requiring high flexibility and a minimal foreign body response, a macroporous, lightweight, or partially absorbable option is often preferred.