Polypropylene in the intra-abdominal position: influence of pore size and surface area.
BACKGROUND
Polypropylene is a material widely used in surgery. Because of its association with formation of enterocutaneous fistulae and adhesions, direct contact between mesh and intestine is avoided. The following study was designed to investigate the adhesive potential of different polypropylene meshes when placed in direct contact with intestine.


METHODS
In an established experimental model, a total of 45 chinchilla rabbits underwent laparoscopic placement of meshes with different pore size (Group I: monofilament PP 0.6 mm, Group II: monofilament PP 2.5 mm, Group III: multifilament PP 4.0 mm) with the Intra-Peritoneal-Onlay-Mesh Technique (IPOM). The degree of adhesion formation was measured after 7, 21, and 90 days, evaluated by an adhesion score, quantified by computer-assisted planimetry, followed by histological and morphometric investigation of the perifilamental granuloma formation.


RESULTS
The heavyweight, small porous polypropylene meshes (PP 0.6) showed significantly stronger adhesion formation at all intervals of investigation compared with the lightweight meshes with a pore size >2.5 mm. Between the two different lightweight mesh variations, there was no significant difference. Granuloma formation was lowest in large-pore-size monofilament meshes (PP 2.5).


CONCLUSIONS
The IPOM rabbit model is suitable for investigation of biomaterials in the intra-abdominal position. Our results show that the adhesive potential is significantly influenced by the pore size. However, the extent of the foreign-body reaction seems also to be influenced by the filament structure, respectively, the surface area, favoring monofilament material.
Department of Surgery, Rhenish-Westphalian Technical University, Pauwelsstrasse 30, 52074 Aachen, Germany. jconze@ukaachen.de
J
J
Conze
R
R
Rosch
U
U
Klinge
C
C
Weiss
M
M
Anurov
S
S
Titkowa
A
A
Oettinger
V
V
Schumpelick
D034841:Abdominal Cavity; D000818:Animals; D001672:Biocompatible Materials / Q000009:adverse effects*; D005260:Female; D005549:Foreign-Body Reaction / Q000209:etiology; D020007:Implants, Experimental; D007422:Intestines; D008422:Materials Testing; D023421:Models, Animal; D010316:Particle Size; D011126:Polypropylenes / Q000009:adverse effects*; D011817:Rabbits; D013499:Surface Properties; D013526:Surgical Mesh / Q000009:adverse effects; D000267:Tissue Adhesions / Q000209:etiology*
D001672:Biocompatible Materials; D011126:Polypropylenes