Full-thickness skin grafts to reinforce the abdominal wall: a cross-sectional histological study comparing intra- and extraperitoneal onlay positions in mice

Introduction: In the repair of complex abdominal wall hernia, there can be a strong preference to avoid synthetic or biological implants as reinforcement material. Autologous full-thickness skin grafts (FTSG) have shown promising results. However, there are few clinical data on the use of FTSG in an intraperitoneal position and rudimentary knowledge about postoperative histological appearance of tissue remodelling and repair. Objective: To investigate the histological appearance of FTSG in the intraperitoneal onlay mesh (IPOM) position. Methods: Isogeneic FTSG was positioned in the IPOM (10 mice) and the onlay position (10 mice). After eight weeks, tissues were harvested for histological analysis. Tissue structure, inflammation and cell survival were investigated with histological and immunohistochemical staining. Results: Morphology was similar in both positions. Luciferase staining indicated both onlay and IPOM graft cell survival, with microvascular networks present. In both positions, FTSG showed ongoing tissue remodelling processes and cystic formations containing hair and epidermis. Low-grade acute phase and chronic inflammation were present. Integration was observed in 50% of the mice with similar appearances in IPOM and onlay grafts. Conclusion: FTSG is tolerated, with comparable results either inside or outside the abdominal cavity, and in line with historic histological evaluations. The results suggest further research on FTSG as a potential future reinforcement material in selected cases of complex abdominal wall hernia repair.