Choosing the Mesh Placement Plane
The plane in which the mesh is placed weighs on the outcome as much as the material: onlay above the fascia, sublay in the retromuscular space, preperitoneal or intraperitoneal. The choice depends on the site and width of the defect, field contamination, patient condition and surgical approach.
The page on meshes and placement planes describes materials and sites in plain terms. Here the point is decision-making: given a defect and a patient, in which plane should the mesh be placed, and why.
The four sites
| Plane | Mesh position | Technical note |
|---|---|---|
| Onlay | Above the closed fascia, in the subcutaneous space | Simple, but more exposed to infection and seromas; requires wide skin flaps |
| Inlay (bridging) | Interposed in the defect | To be avoided as definitive repair: association with the highest recurrence rates |
| Sublay | Retromuscular (Rives-Stoppa) | Reference plane: protected, vascularised, favoured by abdominal pressure |
| Intraperitoneal (IPOM) | In contact with the viscera | Requires anti-adhesive composite meshes; issues with adhesions and fixation |
Why sublay is the reference
Case series and guidelines agree: when the retromuscular plane can be reached, it offers the lowest rates of recurrence and infectious complications. The reasons are mechanical — intra-abdominal pressure presses the mesh against the wall instead of detaching it — and biological: the mesh integrates between two vascularised layers, away from the skin and the viscera. Modern minimally invasive accesses (eTEP, robotics) were developed precisely to bring the mesh into this plane without an extended laparotomy.
The selection criteria
- Defect width (W classes of the EHS classification): small defects can tolerate simpler planes; wide ones require sublay, often with component separation
- Site: the midline offers the retromuscular space; lateral defects require preperitoneal planes or wide overlaps
- Field contamination: in clean-contaminated or contaminated fields the choice of material (large-pore synthetic, absorbable biosynthetic) matters as much as the plane
- Patient factors: obesity, diabetes, immunosuppressive therapies and previous radiotherapy push towards protected planes and pre-operative optimisation
- Available approach: open, laparoscopic or robotic, in relation to the team's experience
Contaminated fields and special cases
In emergencies or contaminated fields definitive reconstruction can be deferred: contamination is controlled first (including with negative pressure therapy, see the page on surgical complications and VAC therapy), then the wall is reconstructed at a second stage. In these scenarios the choice between immediate and deferred repair weighs more than the choice of any single plane.