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Hernia Types and Mesh Selection
A hernia is the protrusion of tissue through a defect in the wall that should contain it. The type names where that defect is — but it is the repair approach, and above all the anatomical plane the mesh will occupy, that determine which mesh properties actually matter.
Why it matters
Naming a hernia tells you where it is, not what to repair it with. The property that changes the mesh requirement most sharply is not the name of the hernia at all: it is whether the mesh will end up in contact with viscera. That single question separates the constructions more decisively than any other.
What a hernia is
A hernia has three parts worth naming: the defect, which is the opening in the wall; the sac, which is the lining pushed ahead of the protruding tissue; and the contents, which is whatever has come through. Repair addresses the defect. The sac and contents are dealt with along the way.
Hernias are conventionally named for the anatomical site of the defect, which is why the vocabulary looks like a tour of the abdominal wall.
The common types
Inguinal hernias occur in the groin, through the inguinal canal, and are by a wide margin the most common. Femoral hernias appear just below the inguinal ligament through the femoral canal, and are less common but anatomically distinct.
Umbilical hernias occur at or immediately around the navel, where the abdominal wall has a natural weak point. Epigastric hernias occur in the midline above it.
Incisional hernias, a subset of ventral hernias, occur through the site of a previous surgical incision — the wall has been cut and repaired, and the repair has given way. They can be large and irregular, which is exactly why they are the group where mesh selection is discussed most.
Hiatal hernias are a different problem: the defect is in the diaphragm at the oesophageal hiatus, and both the repair and the question of whether to use mesh at all are considered separately from abdominal wall hernias.
The plane matters more than the name
Where the mesh sits in the abdominal wall is the decision that drives everything else. In an onlay the mesh lies on top of the fascia; in a sublay — retromuscular or preperitoneal — it sits behind the muscle but still outside the peritoneum; in an intraperitoneal placement it lies inside the abdominal cavity.
Only the last of those puts the mesh in contact with bowel, and that is the case a composite or barrier construction exists to address: one face intended for tissue ingrowth, the other a smooth barrier facing the viscera. A plain polypropylene mesh is not designed for that position. Mesh construction covers how those laminates are built.
Open versus laparoscopic changes what the mesh has to do
In an open repair the mesh can be placed flat by hand, trimmed, and fixed from either side. In a laparoscopic repair the same mesh has to be rolled, passed through a port, unrolled in the cavity, positioned without being able to grasp both faces, and fixed from one side only.
That makes handling properties — how the mesh unrolls, whether it holds a memory of the fold, how it drapes — into functional requirements rather than conveniences, and it makes compatibility with a particular fixation method part of the choice. Mesh fixation covers tackers, sutures and adhesives.
Where pore size and weight come in
Pore size and areal density are the properties most often quoted and most often oversimplified. Lighter is not automatically better: reducing material reduces stiffness and can reduce strength, and the pore geometry that follows from the knit affects how tissue integrates with the mesh.
They are trade-offs to be matched to the repair, not a ranking. Mesh pore size and weight sets out what the two properties actually describe.
Overlap and size
A mesh must extend well beyond the margins of the defect rather than merely covering it, so that the forces across the repair are carried by the surrounding wall and not concentrated at the edge of the hole. How much overlap a given technique calls for is a surgical decision governed by the technique and the device’s instructions for use.
Not every hernia is repaired with mesh
Small defects are sometimes closed with sutures alone, and there are circumstances — a contaminated or infected field being the clearest — in which the calculus around implanting a permanent synthetic changes entirely. Whether to use mesh, which mesh, and where to put it are clinical decisions for the operating surgeon.
Key terminology
- Defect
- The opening in the abdominal wall through which tissue protrudes. What a repair is addressing.
- Sac
- The layer of lining pushed ahead of the protruding contents.
- Ventral hernia
- A hernia of the anterior abdominal wall. Incisional hernias are the subset occurring through a previous incision.
- Onlay
- Mesh placed on top of the fascia, superficial to the muscle layer.
- Sublay
- Mesh placed behind the muscle — retromuscular or preperitoneal — but outside the peritoneum.
- Intraperitoneal (IPOM)
- Mesh placed inside the peritoneal cavity, where it can contact viscera. The placement that calls for a barrier construction.
- Overlap
- The margin by which the mesh extends beyond the edges of the defect.
- Recurrence
- A hernia returning at the same site after repair.
Technical characteristics
- Inguinal
- Groin, through the inguinal canal — the most common type
- Femoral
- Below the inguinal ligament, through the femoral canal
- Umbilical
- At or immediately around the navel
- Epigastric
- Midline of the abdominal wall above the navel
- Incisional / ventral
- Through the site of a previous surgical incision
- Hiatal
- Oesophageal hiatus of the diaphragm; considered separately
- Decisive variable for mesh choice
- The anatomical plane the mesh will occupy
- Decisive question
- Will the mesh be in contact with viscera?
How it compares
| Placement | In contact with viscera? | What becomes decisive |
|---|---|---|
| Onlay — on the fascia | No | Fixation and handling |
| Sublay — retromuscular or preperitoneal | No | Conformability, pore size and weight |
| Intraperitoneal (IPOM) | Yes | A composite or barrier construction, with a visceral-facing surface |
What clinicians weigh when selecting
The plane
Whether the mesh will touch bowel is the question that separates plain from composite construction. It outranks the name of the hernia.
The approach
A laparoscopic repair turns handling and unrolling behaviour into functional requirements, and constrains which fixation methods are usable.
The field
Contamination changes the calculus around implanting a permanent synthetic material entirely.
Fixation
The mesh and the way it will be held are chosen together; not every fixation method suits every construction or position.
The instructions for use govern
Indications, placement, contraindications and any restriction on position are stated in each device’s instructions for use, which is the controlled document.
Frequently asked questions
What is the most common type of hernia?
Inguinal hernias, which occur in the groin through the inguinal canal, are by a wide margin the most common type.
Does every hernia need mesh?
No. Small defects are sometimes closed with sutures alone, and there are situations — a contaminated field, for instance — where implanting a permanent synthetic mesh is weighed very differently. Whether to use mesh is a clinical decision for the operating surgeon.
Which mesh is used for laparoscopic hernia repair?
It depends on the plane the mesh will occupy rather than on the approach itself. If the mesh will lie inside the peritoneal cavity in contact with viscera, a composite or barrier construction is what that position calls for. Laparoscopy also puts a premium on how the mesh unrolls and lies flat.
Why is a composite mesh used when the mesh will touch bowel?
Because the two faces have different jobs. One side is intended to integrate with the abdominal wall, while the visceral side is a smooth barrier layer. A plain polypropylene mesh is not constructed for that position.
Does mesh weight matter?
It is a trade-off rather than a ranking. Reducing material reduces stiffness and can reduce strength, and the pore geometry that comes with the knit affects tissue integration. Lighter is not automatically better; it is matched to the repair.
Can a hernia come back after a mesh repair?
Recurrence is possible after any hernia repair. It is multifactorial — the size and site of the defect, the technique, the placement and fixation of the mesh, and patient factors all contribute — which is why the surgical decisions around placement and overlap receive the attention they do.
Instructions for use
This article describes hernia types and the reasoning by which mesh properties are matched to a repair. It does not state indications, contraindications, placement restrictions or technique for any individual device. Those are given in the instructions for use supplied with the product, which is the controlled document and the only correct source for them.
Medical & regulatory notice
This article is general reference information for healthcare professionals about how a class of device works. It is not a substitute for the instructions for use supplied with any product, it is not clinical guidance, and it does not describe the regulatory status of any particular device in any particular market. Product availability, indications and classification differ between jurisdictions. Clinical decisions about a patient are for the treating clinician.