title: Immediate postoperative changes in synthetic meshes - In vivo measurements.
abstract: OBJECTIVE
  Immediate post-operative structural changes in implanted synthetic meshes are believed to contribute to graft related complications. Our aim was to observe in vivo dimensional changes at the pore level.
  
  
  METHODS
  Two different polyvinylidine fluoride (PVDF) meshes, CICAT and ENDOLAP (Dynamesh, FEG Textiltechnik) were implanted in 18 female Sprague Dawley (n=9/group). The meshes (30×25mm(2)) were overlaid on a full thickness incision (2×1cm(2)) and sutured on the abdominal wall. All animals underwent microCT imaging (res. 35µm/px) at day 1 and 15 postsurgery. A customized procedure was developed to semi-automatically detect the pore centers from the microCT dataset. Horizontal (transverse) and vertical (cranio-caudal) inter-pore distances were then recorded. The overall mesh dimensions were also noted from 3D models generated from in vivo microCT datasets. Inter-pore distances and the overall dimensions from microCT images of the meshes set in agarose gel phantom were used as controls. Mann-Whitney U test was done to check for significant differences.
  
  
  RESULTS
  Number of measurable vertical and horizontal inter-pore distances was 56.5(10.5) and 54.5(14.5) [median (IQR)] per animal. At day 1, we observed a 4.3% (CICAT) and 4.6% (ENDOLAP) increase in vertical inter-pore distance when compared to controls (p<0.001, p=0.003, respectively). Measurements fell back to phantom values by day 15 (3.7% and 4.9% decrease compared to day 1, p<0.001 for both). The horizontal inter-pore distances for ENDOLAP increased by 1.4% (p=0.003) during the two weeks period. The overall mesh dimensions did not change significantly day 1 and day 15. The in vivo measurement of the overall mesh dimensions demonstrated a 15.9% reduction in mesh area as compared to that in phantom controls.
  
  
  CONCLUSIONS
  We report for the first time, in vivo changes in pore dimensions of a textile implant. This study clearly demonstrates the dynamic nature of a textile implant during the tissue integration process. For studied PVDF meshes, the process of tissue integration leads to limited but significant reduction over time as observed at the pore level. Remarkably the extent of this reduction does not account for the change in overall mesh dimensions.
authors.affiliation: Department of Development and Regeneration, Cluster Organ Systems, Biomedical Sciences, KU Leuven, and Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium; Interdepartmental Center for Surgical Technologies, Faculty of Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Sindhwani
authors.affiliation: Department of Development and Regeneration, Cluster Organ Systems, Biomedical Sciences, KU Leuven, and Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium; Interdepartmental Center for Surgical Technologies, Faculty of Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Liaquat
authors.affiliation: Department of Development and Regeneration, Cluster Organ Systems, Biomedical Sciences, KU Leuven, and Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium; Interdepartmental Center for Surgical Technologies, Faculty of Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Iva
authors.initials: I
authors.lastname: Urbankova
authors.affiliation: Department of Development and Regeneration, Cluster Organ Systems, Biomedical Sciences, KU Leuven, and Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium; Interdepartmental Center for Surgical Technologies, Faculty of Medicine, KU Leuven, Leuven, Belgium; Biomedical MRI unit/ Molecular Small Animal Imaging Center (MoSAIC), Department of Imaging and Pathology, Faculty of Medicine, KU Leuven, Belgium.
authors.forename: Greetje
authors.initials: G
authors.lastname: Vande Velde
authors.affiliation: Department of Development and Regeneration, Cluster Organ Systems, Biomedical Sciences, KU Leuven, and Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium; Interdepartmental Center for Surgical Technologies, Faculty of Medicine, KU Leuven, Leuven, Belgium; Biomedical MRI unit/ Molecular Small Animal Imaging Center (MoSAIC), Department of Imaging and Pathology, Faculty of Medicine, KU Leuven, Belgium.
authors.forename: Andrew
authors.initials: A
authors.lastname: Feola
authors.affiliation: Department of Development and Regeneration, Cluster Organ Systems, Biomedical Sciences, KU Leuven, and Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium; Interdepartmental Center for Surgical Technologies, Faculty of Medicine, KU Leuven, Leuven, Belgium. Electronic address: Jan.Deprest@uzleuven.be.
authors.forename: Jan
authors.initials: J
authors.lastname: Deprest
mesh_terms: D000818:Animals; D005260:Female; D008422:Materials Testing; D011145:Polyvinyls; D016062:Porosity; D011184:Postoperative Period; D051381:Rats; D017207:Rats, Sprague-Dawley; D013526:Surgical Mesh; D055114:X-Ray Microtomography; D005465:Fluorocarbon Polymers
chemical_list: D011145:Polyvinyls; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers
keywords: Graft related complications; Hernia; Image analysis; Micro-CT; Prolapse