A hernia occurs when an internal organ or tissue pushes through a weak spot in the surrounding muscle or fascia, often in the abdominal wall. Surgical repair is required to push the protruding tissue back into place and reinforce the compromised area. To strengthen this weakened tissue and reduce the chance of the hernia returning, surgeons commonly implant a device known as surgical mesh. This mesh acts as a scaffold for new tissue growth, providing a more durable repair than simply stitching the original tissue together.
The Intended Permanence of Hernia Mesh
Modern hernia mesh is designed to be a permanent structural component and does not require routine replacement. The primary goal is to provide long-term reinforcement to the abdominal wall defect. This permanence is achieved through a biological process called tissue integration, or fibrosis.
The body responds to the implanted mesh by growing scar tissue through and around its porous structure. This process securely incorporates the mesh into the surrounding tissue, making it a permanent part of the body wall. Complete integration, which provides full reinforcement, can take months up to a year, though initial setting occurs faster. A repair using permanent mesh is expected to last for many years.
Factors Leading to Mesh Removal or Revision
While mesh is designed for permanence, complications can arise that necessitate surgical intervention, such as removal, revision, or replacement. These interventions are performed only in response to a medical problem, not as standard maintenance. The most frequent reason for reoperation is the recurrence of the hernia, which can happen in approximately 16% of cases within ten years of the initial surgery.
Chronic pain is another significant factor, affecting about 10–15% of patients, defined as pain lasting longer than three months. This discomfort is often related to nerve entrapment, where the mesh or the resulting scar tissue presses on a nerve, or from inflammation and foreign body reaction. The mesh may also migrate or shrink over time, which can lead to discomfort, distortion, or the formation of a localized mass called a meshoma.
Infection represents another complication, which can be acute (occurring soon after surgery) or delayed (developing years later). Because the mesh is a foreign material, bacteria can colonize its surface, making the infection very difficult to treat with antibiotics alone. Late-onset infections have a low incidence, between 0.1% and 0.3%, but often require complete removal of the mesh to fully resolve the problem. In rare instances, the mesh can also erode into nearby organs, such as the bowel, which is a severe complication requiring immediate surgical removal and repair.
Material Differences and Long-Term Performance
The long-term performance and complication risk of a hernia repair are closely tied to the material used in the mesh. The most common type is synthetic mesh, often made from polypropylene or polyester, which is designed to be permanent. Synthetic meshes are durable and are associated with a low risk of recurrence, providing long-lasting reinforcement. However, their synthetic nature can lead to a more pronounced foreign body reaction, which may contribute to chronic pain or shrinkage.
An alternative is biologic mesh, derived from animal or human tissue and processed to be absorbed by the body over time. Biologic meshes are used in high-risk situations, such as repairs in contaminated surgical fields, because they are thought to better resist infection. However, biologic meshes do not provide permanent reinforcement and are associated with a shorter time-to-recurrence than synthetic meshes. Some newer meshes, called long-acting resorbable meshes, combine synthetic and absorbable components, offering temporary support while promoting tissue growth, and have shown promising long-term results against recurrence.
Surgical Approaches for Mesh Complications
When a complication requires surgical intervention, the approach is tailored to the specific problem.
Complete Excision
For severe complications like deep infection or bowel erosion, a complete excision (full removal of the mesh) is necessary. This procedure is complex because the mesh is integrated with the patient’s tissue, and its removal must be done carefully to avoid damaging surrounding structures.
Revision
In cases of chronic pain due to nerve entrapment or a minor recurrence, a revision may be performed. This involves adjusting the mesh, removing only a small portion, or releasing the entrapped nerve.
Replacement
If the hernia has recurred due to mesh failure or movement, a replacement procedure is common. This involves removing the old mesh and implanting a new one, often choosing a different mesh type or surgical technique to improve durability. The decision on the approach is determined by the nature of the complication and the surgeon’s assessment.