Small Intestine Submucosa (SIS) Implants in Experimental IPOM Repair

Background Synthetic meshes can cause adverse effects (e.g., adhesions, mesh infection) in intraperitoneal onlay mesh repair (IPOM). Although data for its biocompatibility as well as degradation behavior is still scarce, small intestine submucosa (SIS) implants have been suggested as a favorable alternative for IPOM repair. The aim of the study was to assess safety and efficacy of SIS used as allo- or xenograft in an experimental model of IPOM repair, with the purpose of creating a critical awareness for specific aspects of the biomesh concept among researchers and surgeons alike. Main outcome parameters were adhesion formation, tissue integration, shrinkage, and dislocation. Materials and Methods Open IPOM repair was performed in 16 Sprague Dawley rats and two minipigs. SIS implants were 2 × 2cm in rats (one per animal) and 6 × 8cm in pigs (four per animal). All implants were fixed with six nonresorbable sutures. Observation period was 17 and 28 d ( n = 8) in rats and 28 d in pigs. Outcome parameters were assessed macroscopically, and histologic samples (H and E staining) were obtained. Results Upon autopsy, SIS appeared to be only moderately integrated. Dislocation of five SIS implants in the rats and of two SIS implants in the pigs were observed although all sutures were still in place. No seroma formation or infection was detected macroscopically, but substantial shrinkage and adhesion formation at the margins of implants and suture sites were frequently observed. Histology confirmed the macroscopic finding of limited integration and substantial shrinkage. The pathomorphology was similar in both species. Conclusions Small intestine submucosa implants are susceptible to shrinkage, dislocation, and adhesion formation in experimental IPOM repair in rats and pigs. These findings are in accordance with literature and warrant further investigations of SIS implants in hernia repair.