Remodeling characteristics and collagen distribution in synthetic mesh materials explanted from human subjects after abdominal wall reconstruction: an analysis of remodeling characteristics by patient risk factors and surgical site classifications.
BACKGROUND
The purpose of this study was to evaluate the associations between patient characteristics or surgical site classifications and the histologic remodeling scores of synthetic meshes biopsied from their abdominal wall repair sites in the first attempt to generate a multivariable risk prediction model of non-constructive remodeling.


METHODS
Biopsies of the synthetic meshes were obtained from the abdominal wall repair sites of 51 patients during a subsequent abdominal re-exploration. Biopsies were stained with hematoxylin and eosin, and evaluated according to a semi-quantitative scoring system for remodeling characteristics (cell infiltration, cell types, extracellular matrix deposition, inflammation, fibrous encapsulation, and neovascularization) and a mean composite score (CR). Biopsies were also stained with Sirius Red and Fast Green, and analyzed to determine the collagen I:III ratio. Based on univariate analyses between subject clinical characteristics or surgical site classification and the histologic remodeling scores, cohort variables were selected for multivariable regression models using a threshold p value of ≤0.200.


RESULTS
The model selection process for the extracellular matrix score yielded two variables: subject age at time of mesh implantation, and mesh classification (c-statistic = 0.842). For CR score, the model selection process yielded two variables: subject age at time of mesh implantation and mesh classification (r (2) = 0.464). The model selection process for the collagen III area yielded a model with two variables: subject body mass index at time of mesh explantation and pack-year history (r (2) = 0.244).


CONCLUSIONS
Host characteristics and surgical site assessments may predict degree of remodeling for synthetic meshes used to reinforce abdominal wall repair sites. These preliminary results constitute the first steps in generating a risk prediction model that predicts the patients and clinical circumstances for which non-constructive remodeling of an abdominal wall repair site with synthetic mesh reinforcement is most likely to occur.
Section of Minimally Invasive Surgery, Department of Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO, 63110, USA.
Jaime A
JA
Cavallo
Andres A
AA
Roma
Mateusz S
MS
Jasielec
Jenny
J
Ousley
Jennifer
J
Creamer
Matthew D
MD
Pichert
Sara
S
Baalman
Margaret M
MM
Frisella
Brent D
BD
Matthews
Corey R
CR
Deeken
D034861:Abdominal Wall / Q000473:pathology* / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003094:Collagen / Q000032:analysis*; D005109:Extracellular Matrix / Q000737:chemistry / Q000473:pathology*; D005260:Female; D005355:Fibrosis / Q000209:etiology / Q000473:pathology; D006801:Humans; D007249:Inflammation / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009389:Neovascularization, Pathologic / Q000209:etiology / Q000473:pathology; D019736:Prostheses and Implants / Q000009:adverse effects*; D019651:Plastic Surgery Procedures / Q000009:adverse effects; D012307:Risk Factors; D013526:Surgical Mesh / Q000009:adverse effects*; D014018:Tissue Distribution
D003094:Collagen