Mesh contraction: in vivo documentation of changes in apparent surface area utilizing meshes visible on magnetic resonance imaging in the rabbit abdominal wall model.
OBJECTIVE
Our aim was to analyze the apparent contraction of meshes in vivo after abdominal wall reconstruction and evaluate histological and biomechanical properties after explantation.


METHODS
Nine New Zealand female rabbits underwent repair of two full-thickness 25 × 30-mm midline defects in the upper and lower parts of the abdomen. These were primarily overlaid by 35 × 40-mm implants of a polyvinylidene fluoride (PVDF) DynaMesh (n = 6) or polypropylene meshes Ultrapro (n = 6) and Marlex (n = 6). Edges of the meshes were secured with iron(II,III) oxide (Fe(3)O(4))-loaded PVDF sutures. Magnetic resonance images (MRIs) were taken at days 2, 30 and 90 after implantation. The perimeter of the mesh was traced using a 3D spline curve. The apparent surface area or the area within the PVDF sutures was compared with the initial size using the one-sample t test. A two-way repeat analysis of variance (ANOVA) was used to compare the apparent surface area over time and between groups.


RESULTS
PVDF meshes and sutures with Fe(3)O(4) could be well visualized on MRI. DynaMesh and Marlex each had a 17 % decrease in apparent surface area by day 2 (p < 0.001 and p = 0.001), respectively, which persisted after day 90. Whereas there was a decrease in apparent surface area in Ultrapro, it did not reach significance until day 90 (p = 0.01). Overall, the apparent surface area decreased 21 % in all meshes by day 90. No differences in histological or biomechanical properties were observed at day 90.


CONCLUSIONS
There was a reduction in the apparent surface area between implantation and day 2, indicating that most mesh deformation occurs prior to tissue in-growth.
Pelvic Floor Unit, A Programme of Gynaecology, Urology and Gastro-Enterology, University Hospitals Leuven, 3000, Leuven, Belgium.
Masayuki
M
Endo
Andrew
A
Feola
Nikhil
N
Sindhwani
Stefano
S
Manodoro
Jarek
J
Vlacil
Alexander Carl
AC
Engels
Filip
F
Claus
Jan A
JA
Deprest
D034861:Abdominal Wall / Q000601:surgery*; D000818:Animals; D004868:Equipment Failure; D005260:Female; D008279:Magnetic Resonance Imaging; D008422:Materials Testing; D011126:Polypropylenes; D011145:Polyvinyls; D011817:Rabbits; D013526:Surgical Mesh; D013537:Sutures; D005465:Fluorocarbon Polymers
D011126:Polypropylenes; D011145:Polyvinyls; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers