A hernia occurs when an organ or fatty tissue pushes through a weakened area in the surrounding muscle or connective tissue, often creating a bulge. Surgical mesh is frequently employed in hernia repair procedures to reinforce these compromised tissues and to minimize the likelihood of the hernia recurring. This medical device acts as a scaffold, providing support to the weakened area while the body heals around it.
Surgical Fixation Methods
Surgeons use several immediate, mechanical techniques to secure hernia mesh during the operation.
Sutures are a common method to initially hold the mesh in place against the surrounding tissue. These sutures provide a direct attachment, ensuring the mesh remains in the desired position immediately after placement.
Another technique involves surgical tacks designed to anchor the mesh to the muscle or connective tissue. Tacks offer a quick and effective way to secure the mesh, particularly in laparoscopic procedures where space is limited. While effective for initial fixation, some studies suggest tacks can be a source of chronic pain.
Fibrin glues or sealants represent a different approach to mesh fixation, offering a less invasive alternative to sutures or tacks. These biological adhesives are applied to the mesh and surrounding tissues, creating a bond that holds the mesh in position. Fibrin glue has been shown to provide strong immediate fixation, potentially reducing postoperative pain and discomfort compared to mechanical fixation methods.
Biological Integration
Beyond the immediate surgical methods, the body initiates a natural process of biological integration, which is essential for the mesh’s long-term stability. The body responds to the implanted mesh by forming scar tissue, a process known as fibrosis, around and into the mesh structure. This scar tissue effectively “grows” into the mesh’s pores, anchoring it securely in place over time.
This integration involves a cellular response, where various cells, including macrophages and fibroblasts, migrate to the mesh site. Macrophages, a type of immune cell, play a role in the initial inflammatory response to the foreign material. Fibroblasts then contribute to the formation of new collagen fibers, which become part of the developing scar tissue, intertwining with the mesh filaments.
The formation of this fibrous capsule around the mesh permanently incorporates it into the body’s tissue. This biological ingrowth provides the long-term reinforcement and stability needed to prevent hernia recurrence. The inflammatory reaction is a necessary part of this integration process that strengthens the mesh-tissue bond.
Mesh Material and Design
The inherent properties of the mesh material and its design significantly influence how well it integrates and is held in place. Synthetic meshes, commonly made from polypropylene, polyester, or expanded polytetrafluoroethylene (ePTFE), are widely used for their strength and durability. Polypropylene mesh, for instance, is known to induce a controlled inflammatory response that promotes tissue ingrowth, forming a strong bond with the surrounding muscle.
The pore size of the mesh is a significant design factor affecting integration. Macroporous meshes, with larger pores, allow for better tissue ingrowth and vascularization compared to microporous meshes. This larger pore size can reduce the foreign body reaction and promote more favorable tissue integration.
Mesh weight also plays a role in how the mesh interacts with the body. Lightweight meshes are designed to reduce the amount of foreign material in the body, potentially leading to less foreign body sensation and improved flexibility. However, heavyweight meshes may offer greater strength for larger defects, though they can be associated with increased foreign body sensation.
Some meshes are also designed to be absorbable or partially absorbable, meaning they degrade and are absorbed by the body over time. These meshes provide temporary scaffolding, allowing the body’s own tissue to strengthen and take over the supportive role as the mesh dissolves. Biologic meshes, derived from animal or human tissue, are another type of absorbable mesh that remodel into the patient’s own tissue.