Hernia Sac Flap Coverage of Mesh in Bony-Edged Ventral Hernia Repair

This trial asks whether covering the inner, bowel-facing surface of a hernia mesh with a flap of the patient's own hernia sac improves healing after repair of a complex ventral (abdominal wall) hernia in which one edge of the defect is bone - for example hernias next to the breastbone and ribs, above the pubic bone, or at the iliac crest. In these "bony-edged" hernias the mesh is both hardest to fix and hardest to cover. There is no fascia on the bony side for the surgeon to stitch the mesh to, and the lining layer of the abdomen cannot be closed underneath the mesh because the plane that carries it stops at the bone. The mesh may therefore be left in contact with the bowel, which can lead to dense adhesions, mesh erosion, chronic pain and, rarely, a fistula. Normally the hernia sac - the thin membrane that lines the hernia - is cut away and discarded. In this trial the surgeon instead preserves it as a living, blood-supplied flap, rotates it underneath the mesh, and stitches it in place as a new lining layer that separates the mesh from the bowel and covers the bony edge. The technique uses only the patient's own tissue: no extra mesh, no donor site and no added cost. One hundred and eighty adults undergoing planned (non-emergency) open repair of a bony-edged complex ventral hernia will be randomly assigned in equal numbers to one of two groups: standard retromuscular (sublay) mesh repair with the added sac flap (90 participants), or standard retromuscular mesh repair alone, with the sac handled in the conventional way (90 participants). Every other step of the operation is the same in both groups. The main question is whether the sac flap reduces the number of participants who develop any wound or mesh problem in the first 30 days after surgery. This is measured as a composite called a surgical site occurrence, which includes wound infection, seroma, haematoma, skin or soft-tissue death, wound breakdown, mesh exposure and fistula. The trial also compares complications needing a drainage or operative procedure, hernia recurrence at 12 months, overall complication severity, operating time, blood loss, hospital stay, readmission, reoperation, pain, quality of life and death. Participants, ward and clinic staff, the doctors who assess the wounds, the radiologist who reads the follow-up scans and the trial statistician will not know which operation was performed; only the operating surgeon will. The group assignment is revealed only during the operation, after the surgeon has confirmed that the defect truly has a bony edge and that the sac is suitable for a flap. Participants are followed for 12 months.

Inclusion Criteria: * Age 18 years or older. * Elective open repair planned for a complex ventral hernia (primary or incisional) in which at least one margin of the fascial defect is formed by bone - that is, a subxiphoid or costal-margin, suprapubic, or iliac or lumbar location - confirmed on cross-sectional imaging (CT or MRI) and at operation. * A hernial sac of sufficient quality and surface area to raise a pedicled flap adequate to cover the planned mesh, as judged at operation. * Planned retromuscular (sublay) synthetic mesh repair, with or without posterior component separation (transversus abdominis release). * Able to give written informed consent and to attend scheduled follow-up for 12 months. Exclusion Criteria: * Emergency or urgent operation (incarceration with strangulation, obstruction, or perforation). * Active intra-abdominal infection, or a contaminated or dirty operative field (CDC wound class III-IV) at the time of randomization. * Planned use of biologic or composite intraperitoneal mesh, or a bridged (non-fascial-closure) repair as the primary plan. * Hernial sac absent, destroyed, densely scarred, or too small to raise a viable covering flap. * Concurrent bowel resection or stoma creation expected to alter the wound-contamination class. * ASA physical status V. * Life expectancy less than 12 months, or active malignancy under treatment with anticipated short survival. * Pregnancy. * Inability or unwillingness to provide informed consent or to comply with follow-up