Related Experiment Video
Updated: May 28, 2026
Use of a Rat Model to Study Ventral Abdominal Hernia Repair
Published on: October 2, 2017
Intraperitoneal Polypropylene Mesh in Clean, Potentially Septic, and Controlled Contamination Fields: An Experimental
Apostolos Makrantonakis1, Ioannis Mantzoros1, Orestis Ioannidis1
14th Surgical Clinic, School of Medicine, Faculty of Health Science, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece.
Abstract:
Background and Objectives: Intraperitoneal onlay mesh (IPOM) reduces ventral/incisional hernia recurrence but raises concern for adhesions and infection, particularly when the operative field is not strictly clean. We aimed to determine how contamination severity modulates the peritoneal response to intraperitoneal polypropylene mesh. Materials and Methods: In a prospective, randomized, blinded rat study, 60 male Wistar rats were allocated to three groups (n = 20/group) and evaluated at postoperative day (POD) 4 and POD 8 (n = 10/timepoint): A, clean mesh placement; B, small-bowel resection with end-to-end anastomosis without spillage ("potentially septic"); and C, mesh placement followed by intraperitoneal inoculation with Escherichia coli and Staphylococcus aureus ("controlled contamination"). The primary outcome was adhesion severity (Van der Ham scale, 0-3). Secondary outcomes included semi-quantitative histological scores (0-4) for neutrophil infiltration, fibroblast proliferation, neoangiogenesis, and collagen deposition. Prespecified non-parametric analyses were applied. Results: All animals completed follow-up; no pre-sacrifice deaths occurred. Adhesion severity showed no statistically significant differences between Groups A and B at either timepoint (mean POD4: 0.3 vs. 0.6; POD8: 0.4 vs. 0.8; p > 0.05). In contrast, Group C demonstrated markedly higher adhesion scores (mean POD4: 2.3; POD8: 2.4; both p < 0.001 vs. Groups A and B), with a substantially greater proportion of grade 2-3 adhesions. Histological parameters paralleled these findings: at both POD4 and POD8, Group C showed significantly higher neutrophil, fibroblast, neoangiogenesis, and collagen scores compared with Groups A and B (all p < 0.001). No statistically significant within-group temporal differences were observed between POD4 and POD8. Conclusions: In this experimental model, intraperitoneal polypropylene mesh demonstrated similar early biological response patterns in clean and controlled contamination settings, whereas established intra-abdominal sepsis was associated with a marked escalation of inflammation, fibroproliferation, and adhesion formation. These findings suggest that selective use of synthetic intraperitoneal mesh may be considered when contamination is controlled, while caution is warranted in frankly septic environments.
Insights
Intraperitoneal onlay mesh (IPOM) showed similar responses in clean and potentially septic environments. However, controlled contamination with bacteria significantly increased adhesion formation and inflammation, indicating caution in septic surgical fields.
Area of Science:
- Surgical innovation
- Biomaterials science
- Inflammatory response
Background:
- Intraperitoneal onlay mesh (IPOM) is effective for ventral/incisional hernia repair but poses risks of adhesions and infection.
- The impact of contamination severity on the peritoneal response to IPOM requires further investigation.
- Understanding mesh behavior in contaminated environments is crucial for surgical safety.
Purpose of the Study:
- To evaluate how varying degrees of contamination affect the peritoneal tissue's response to intraperitoneal polypropylene mesh.
- To compare adhesion formation and histological changes in response to mesh placement under clean, potentially septic, and controlled contamination conditions.
- To provide evidence-based guidance on the selective use of IPOM in contaminated surgical fields.
Main Methods:
- Prospective, randomized, blinded rat study involving 60 Wistar rats.
- Three groups: clean mesh placement, mesh with potential contamination from bowel resection, and mesh with controlled bacterial inoculation (E. coli, S. aureus).
- Assessment at postoperative days 4 and 8, evaluating adhesion severity and histological parameters (neutrophil infiltration, fibroblast proliferation, neoangiogenesis, collagen deposition).
Main Results:
- No significant difference in adhesion severity between clean and potentially septic (bowel resection) groups.
- Controlled contamination group exhibited significantly higher adhesion scores (grades 2-3) compared to clean and potentially septic groups (p < 0.001).
- Histological analysis revealed significantly increased neutrophil infiltration, fibroblast proliferation, neoangiogenesis, and collagen deposition in the controlled contamination group (p < 0.001).
Conclusions:
- Intraperitoneal polypropylene mesh elicits comparable early biological responses in clean and potentially septic conditions.
- Established intra-abdominal sepsis significantly escalates inflammation, fibroproliferation, and adhesion formation around the mesh.
- Selective use of synthetic intraperitoneal mesh may be feasible in controlled contamination scenarios, but caution is advised in frankly septic environments.
