Most commonly, omentum is contained within the sac, but small and large bowel may also be present. Frequently the omentum will have formed adhesions to various areas of the sac, thus preventing reduction of the hernia. Sharp dissection is required to detach hernial contents from the sac as well as from the peritoneum around the neck of the sac as it joins the peritoneum. When there is a strong suspicion of gangrenous intestine within the sac, the abdominal cavity should be entered through an extended midline incision that enters either above or below the umbilicus. This incision is extended to the fascial defect and up the side of the sac so as to allow complete mobilization of the incarcerated bowel. The intestine is either reduced or resected as indicated. In the majority of cases, omentum is incarcerated within the sac.
In these patients, the sac may be opened (Figure 2). If the omentum cannot easily be freed and/or reduced, it is wise to resect it with sequential clamping and suture ligature placement. When the contents of the sac have been reduced and its neck has been well defined, a decision is made as to how to repair the fascial defect.
In general, when the defect is less than 2 cm in diameter, the peritoneum is closed and the excess sac excised. The perimeter of the fascial defect is cleaned of fat both anteriorly and posteriorly, and a primary repair is performed using interrupted 00 sutures that may be of a delayed absorbable or nonabsorbable nature (Figure 3). This primary repair is performed only for small defects of 2.5 cm or less.
If an intermediate-sized defect in the range of 2 to 4 cm is found, many surgeons prefer to repair it with the two layer “vest-over-trousers” (Mayo) technique (Figures 4, 5, and 6). The upper fascia is imbricated over the lower fascia with a row of interrupted 00 sutures. These begin and end high on the vest, while the trousers are secured in a horizontal manner at the belt line (Figure 4). When these sutures are secured, the free superior edge (vest) overhangs the inferior fascia (trousers) and a second layer of interrupted 00 sutures is used to secure the free edge (Figure 5A). The technique is illustrated schematically in the cross-sectional view illustrated in Figure 6.
Many surgeons believe that a medium to large defect should be repaired with mesh, as primary tissue repairs in large hernias have a significant recurrence rate. The preferred site for placement of the mesh is posterior to the defect and posterior rectus sheath. If the zone between the peritoneum and posterior rectus sheath can be freely dissected, some surgeons use a polypropylene mesh after first being certain that the omentum is directly behind this region when the umbilical hernia sac is closed. Alternatively, if this plane cannot be developed and the mesh must be placed in an intraperitoneal position, a dual-sided mesh is used wherein the smooth, nonadherent expanded polytetrafluoroethylene (PTFE) surface is posterior toward the omentum and bowel, while the polypropylene screen-like mesh is anterior against the peritoneum and posterior fascia (Figure 6A). The mesh should be sized to extend 3 to 5 cm beyond the anticipated edges of the closed defect. This mesh is secured with nonabsorbable 00 mattress sutures that are placed full-thickness through the linea alba at the 12 and 6 o'clock positions and through the rectus sheaths and muscle at the 3 and 9 o'clock positions. These sutures should secure only the polypropylene mesh and should not go full-thickness through the PTFE, as this may present a free intra-abdominal loop that may catch a loop of bowel. The anchoring sutures are tied and the defect is closed either vertically or transversely using interrupted 00 sutures.
After careful hemostasis is obtained, the apex of the subcutaneous tissue beneath the umbilicus is sutured down to the linea alba with 00 absorbable sutures. This produces the desirable ingoing bellybutton. Further absorbable sutures are used to obliterate the subcutaneous dead space. A triple-bite suture that secures Scarpa's fascia to the deep fascia and then the Scarpa's fascia on the other side of the incision minimizes the space for a potential accumulation of serum or a hematoma. When the hernia is quite large, a closed-system Silastic suction catheter may be placed through an adjacent stab wound.
Special attention is given to the avoidance of abdominal distention. An adhesive tape strip 3 in. wide is liberally applied across the abdomen, and the patient may use an abdominal binder for approximately 1 month. The patient is warned to avoid overly heavy lifting and straining.