Hernia Mesh

Permanent: this type of mesh is made of a material that is not degraded. Permanent meshes in general must be removed when in contact with an infection although some lightweight large-pore meshes have been salvaged (i.e. did not have to be removed) in the setting of infected fields.

1. Polypropylene: perhaps the least disordered collagen reaction. Examples include Prolene, Marlex, Parietene, 3DMax, Ventralight, and Ventralex.

2. Polyester: this appears to have a more disordered collagen reaction. Examples include Progrip, and Symbotex.

3. PTFE: this is gortex and is often thick and has been associated with bowel erosion years later.

4. Partially absorbable: a lighter weight permanent scaffold within an absorbable (see below) mesh. Examples include Ovitex.

Absorbable: this type of mesh is resorbed over time. These meshes are sometimes utilized in infected/contaminated fields.

5. Phasix: this is resorbed over the course of 12-18 months.

6. Vicryl: this material is resorbed over the course of a few months.

7. Biologics: these meshes are made out of animal tissue / collagen and usually last for a few months.

Mesh weight density is a measure of how "heavy" or "dense" a mesh is. As would be expected, in general, a "heavier" mesh will have a higher physical strength. But remember a mesh's utility does not rest solely on its physical strength and characteristics, but also in its ability to elicit the body's immune response and serve as a scaffold for a scar plate. As mesh weight increases, this may also increase foreign body sensation. Also heavier meshes tend to contract more over time in the body. 

Larger hernias with weaker tissue may benefit from heavier meshes, whereas lower tension hernia repairs may benefit from lighter meshes.

There are a few different classifications published. We use the following schema:

• Light-weight meshes: density < 50 g/m²

• Medium-weight meshes: density 50 — 80 g/m²

• Heavy-weight meshes: density > 80 g/m²

Pore size in a mesh referes to the space between the material fibers. With larger pore size, it is easier for cells and tissue to intermingle with the mesh leading to better tissue ingrowth and mesh incorporation. Smaller pore size can lend itself to faster deposition of a scar plate.

There are different classifications proposed, we utilize the following schema:

• Microporous meshes: pore size < 100 μm (0.1 mm)

• Small pore meshes: pore size 0.1 — 1 mm

• Medium pore meshes: pore size 1 — 2 mm

• Macroporous meshes: pore size > 2 mm

When mesh is in contact with the bowel (e.g. esophagus, small intestine, etc), it is important that mesh has a barrier non-adhesive coating -- this is to prevent adhesions and decrease the risk of future fistulization (where mesh erodes into bowel). The goal is for the non-adhesive coating to last long enough for the mesh to be "peritonealized" -- that is, covered with the body's own peritoneum. Now in general, it is usually best to keep mesh out of the peritoneal cavity wherever possible by placing it preperitoneally, or in the TAR space, or even in the onlay space.

• SAGES and AHS Hernia Mesh Review and Catalog

• What are the indications for heavy vs medium vs lightweight mesh in hernia repair?

• The search for ideal hernia repair; mesh materials and types

• Definition of Mesh Weight and Pore Size in Groin Hernia Repair: A Systematic Scoping Review of Randomised Controlled Trials

• Past, Present and Future of Surgical Meshes: A Review

• Polyester vs polypropylene, do mesh materials matter? A meta-analysis and systematic review

• Mesh Weight in Reoperation for Recurrence After Laparoscopic Inguinal Hernia Repair

• Association of mesh weight with adverse outcomes: a cohort study including 123,880 inguinal hernia repairs

• Comparison of Different Weight Meshes in Ventral/Incisional Hernia Repair, the Outcomes of Systematic Review and Meta-analysis

• Lightweight versus heavyweight mesh in laparoscopic inguinal hernia repair: a meta-analysis

• Does the Weight Matter? Short-Term Outcomes of Lightweight Versus Heavyweight Three-Dimensional Anatomical Mesh in Minimally Invasive Inguinal Hernia Repair

• Is mesh pore size associated with the outcome in laparo-endoscopic inguinal hernia repair? - a registry-based multivariable analysis

• Weighing the benefits: Exploring the differential effects of light-weight and heavy-weight polypropylene meshes in inguinal hernia repair in a retrospective cohort study

• Lightweight mesh is recommended in open inguinal (Lichtenstein) hernia repair: A systematic review and meta-analysis

• Factors predicting chronic pain after open mesh based inguinal hernia repair: ​A prospective cohort study

• Meta-analysis of randomized controlled trials comparing lightweight and heavyweight mesh for Lichtenstein inguinal hernia repair

• Standard polypropylene mesh vs lightweight mesh for Lichtenstein repair of primary inguinal hernia: a randomized controlled trial

• Lightweight versus heavyweight in inguinal hernia repair: a meta-analysis

• Meta-Analysis of Randomized Controlled Trials Comparing Lightweight and Heavyweight Mesh for Laparoscopic Total Extraperitoneal Inguinal Hernia Repair

• Lightweight Versus Heavyweight Mesh in Laparoscopic Inguinal Hernia Repair: An Updated Systematic Review and Meta-Analysis of Randomized Trials

• A meta-analysis comparing lightweight meshes with heavyweight meshes in Lichtenstein inguinal hernia repair