Making Sense of Hernia Mesh

Dr. Towfigh has increasingly turned to hybrid mesh. "In my opinion, synthetic mesh seems to have evolved into a lower-quality product than it used to be," she says. "What used to be a higher-quality resin to make mesh may have been switched off to lower-quality resin, so now we're seeing much more inflammation, chronic pain and mesh reaction in patients that undergo synthetic mesh repairs than we used to."

Although rare, patients who do experience mesh reactions suffer from chronic fatigue, joint pain, swelling, hair loss, ringing of the ear, visual changes, brain fog, memory problems and rashes on different parts of their body. "I see the same thing over and over again," says Dr. Towfigh. "They get better after the mesh is removed."

The risks associated with synthetic meshes has led her to use hybrid mesh more frequently. "Hybrid meshes work really well in my practice," she says, "and I think over time you'll see more and more usage of these meshes."

• Pore size. This refers to the space between the fibers of the mesh.

"Pore size is probably the most important characteristic in my mind," says Dr. Blatnik. "A macroporous design — a pore size in the neighborhood of 2 to 3 millimeters — allows for native tissue ingrowth in between the fibers."

That helps do a couple things, he explains. It reduces the foreign body reaction to the mesh and allows for native vascular ingrowth in between the fibers that may alleviate some infection risks.

"A larger pore size allows the body to heal into the mesh faster," agrees Laura Mazer, MD, MS, an assistant professor at the University of Michigan in Ann Arbor. "It's treated less like a solid foreign body and more like a lattice work that the body scars over. The mesh gets incorporated and won't get infected or cause irritation."

• Weight (density). Measured in grams per meter squared, "Density ultimately is reliant on the size of the pore — if you have a smaller pore size, you have more fibers woven in, so you have a higher density," says Dr. Blatnik.

"In general, we tend to prefer a larger pore size, but a lower-weight mesh, which tends to have a little more compliance and be a little more comfortable for the patient," says Dr. Mazer. "It's less likely the patient will have any sensation of the mesh. That being said, there have been meshes in the past that have been too lightweight and had a tendency to tear. It's a balancing act. A material like polypropylene has the tensile strength, especially in bigger ventral hernias."

• Barriers. Different meshes have different barriers or coatings that can be made of biologic or chemical materials. The purpose of the coatings is to reduce adhesions. "The choice for barriers ultimately depends on where you put the mesh," says Dr. Blatnik. "A lot of surgeons now strive to put the mesh in between the layers of the abdominal wall, underneath near the intestine, which we call intraperitoneal style of mesh. That alleviates the need to put in a barrier-coated mesh."

Conversely, he says, barrier-coated mesh should be placed in the peritoneal cavity to repair an umbilical or ventral hernia. "Coated mesh will prevent the bowel from sticking to the mesh, and prevents adhesions or scars from forming to that side of the mesh," says Dr. Mazer.

There's no perfect mesh for every patient or for every repair. Surgeons run through a mental checklist when assessing their mesh options. What are the goals for that operation? Where's the hernia located? How big is it? Has it been repaired before? All of those characteristics ultimately play into the determination of what kind of mesh and procedure surgeons use and perform for individual patients.

"It comes down to the experience of the surgeon and their understanding of meshes to tailor what mesh they use for what patient and for what procedure," says Dr. Blatnik. "I commonly use four different styles of meshes, and subsequent sizes within those styles. I have a playbook in my mind for different patients and what meshes we're going to use for their problems, and then tailor the size to the individual patient and the issue they have."

Dr. Mazer typically uses a lightweight polypropylene mesh for most hernias unless there's a reason not to. "I use it in part because of the amount of evidence and the amount of stability it has, how long it's been around and my comfort level with it," she explains.

Patient characteristics — comorbidities, obesity, smoking, future surgical needs, plans to have children — also come into play.

"The key is evaluating each hernia and each patient individually, and hopefully having a large toolbox of repair options and mesh options so you can pick the right repair for the right patient," says Dr. Mazer.

"Most hernias are best treated with standard repairs, but not all. Especially as we start seeing the bigger hernias, hernia recurrences or patients who had reactions to mesh. Having a broader toolbox to offer those patients can be really powerful." OSM