Preperitoneal and Intramuscular

The combination of preperitoneal and intramuscular repairs is utilized most commonly with flank and lateral ventral hernias. The defect is usually irregular in shape, surrounded by extremely weak muscle and thin fascia, and frequently has close proximity to bone. The result is that simple direct suture repairs will not hold. By adding two layers of mesh, preferably polypropylene that incorporates into the fascia with collagen deposition, a remarkably strong repair is achieved. The hernia sack is dissected free of the surrounding tissues, with great care taken to avoid injury to the sack or it's contents. The peritoneum is then carefully dissected free from the underside of the deep fascia for a distance of at least the size of the defect from every edge. This is rarely achieved in all directions but is commonly exceeded in at least one direction. It is important to overlap any bony margin as far as possible in this layer; sutures are not used into periostium since they are very painful and will not support a repair. However, if the mesh overlaps the bone two-three times the size of the defect, the mesh will be incorporated into the fascia at that level adding tremendous strength. The majority of the time taken for this repair is used in these two steps of freeing the hernia sack and developing wide tissue planes in the preperitonium.

Once the preperitoneal space is widely dissected, then a piece of polypropylene mesh is placed behind the deep fascia. Care is taken to smooth out the mesh under the fascia with maximal overlap from the defect edge in all directions. The fascial defect edge is then sutured down to the mesh with running monofilament suture. Occasionally the mesh can be entirely covered with the first layer of fascia and muscle, however most of the time the proper tension on this fascia layer requires that a small ellipse of mesh remains exposed. It is important not to use tacking sutures to hold the mesh stretched out under the fascia; those sutures will create an ischemic weak spot at the unprotected edge of the mesh inviting herniation around an otherwise strong repair.

The next layer is variable depending upon the tissue available. Great care should be taken during the dissection to identify the different muscle and fascia layers so that at least two tissue planes can be re-created for mesh reinforcement. This second layer is frequently beneath the external or internal oblique muscles, and a wide tissue plane is common. The bony edges are limitations, but other directions are easily developed. Another piece of polypropylene mesh is cut to shape, and placed into this wide intramuscular layer. Again the mesh is sutured to the edge of the fascia defect, avoiding placing any sutures through fascia that is not protected by several centimeters of surrounding mesh reinforcement. The adipose and skin are close in the routine fashion, trimming redundant or non-viable skin. A closed suction drain is recommended.

1. Not previously in the literature; personal experience by HerniaRegistry.com editor; Bill Welch MD, 2001