Background:Pilonidal disease is a common inflammatory condition mostly affecting young males. Malignant degeneration of a pilonidal cyst is rare, with incidence estimated at 0.1%. The most common type is squamous cell carcinoma and the treatment of c...

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.

Background/Objectives: The safety of intraperitoneal mesh placement in contaminated fields remains controversial because of the increased risk of inflammation and adhesion formation. N-acetyl-L-cysteine (NAC) has antioxidant, pro-fibrinolytic and antibiofilm actions that could attenuate this response. The aim of this study is to determine whether NAC reduces mesh-related inflammation in a septic model created by intraperitoneal Escherichia coli (E.coli) inoculation. The primary comparison was prospectively defined between E. coli–inoculated animals treated with NAC (D) and those without NAC (B). Groups without E. coli (A,C,E) are presented for context and were compared previously. Methods: In this randomized, double-blind experimental model (five groups, n = 20 per group), all rats underwent midline laparotomy with intraperitoneal placement of a composite mesh, followed by standardized ciprofloxacin administration. The septic groups received intraperitoneal E. coli, while the NAC-treated groups additionally received intraperitoneal NAC (150 mg/kg). Serum levels of IL-1α, IL-6, and TNF-α were measured on postoperative days 7, 14, and 21. On day 21, adhesions were graded using the Modified Diamond system, histology (inflammatory infiltration, fibrosis, neovascularization) was scored, and mesh cultures were obtained. Cytokine data were analyzed with repeated-measures ANOVA, while categorical or ordinal outcomes were assessed using χ² or Fisher’s exact tests with Bonferroni-adjusted pairwise comparisons. Results: E. coli inoculation significantly increased adhesion burden and worsened histologic scores compared with controls (both p < 0.001). NAC administration in the septic model significantly reduced adhesions and improved all histologic domains relative to E. coli alone (all p ≤ 0.003), with values comparable to controls (non-significant across domains). For cytokines, there was a significant overall group effect for IL-1α, IL-6, and TNF-α (all p < 0.001), without a main effect of time or time × group interaction. Pairwise contrasts showed lower IL-1α (p = 0.024), IL-6 (p < 0.001), and TNF-α (p < 0.001) levels in group D versus B, and lower IL-6 and TNF-α in group D versus A (both p < 0.001). Mesh culture positivity rate was higher in group B than A (p < 0.001) and showed a non-significant reduction in group D versus B (p = 0.10). No perioperative deaths occurred. Conclusions: NAC attenuated septic, mesh-associated inflammation—normalizing adhesions and histology and reducing IL-6 and TNF-α— supporting its role as a host-directed adjunct alongside antibiotics. Further translational studies are warranted to define the optimal dose, timing, and clinical indications.