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The behavior of different types of polytetrafluoroethylene (PTFE) prostheses in the reparative scarring process of abdominal wall defects
J. Buján, L.A. Contreras, A. Carrera-San Martín and J.M. Bellón
Department of Morphological Sciences and Surgery, Faculty of Medicine, University of Alcala de Henares, Madrid, Spain
Offprint requests to: Prof. J . Bujan, Department of Morphological
Sciences and Surgery, Faculty of Medicine, University of Alcala de
Henares, Crta. Madrid·Barcelona, km 33.600, 28871-Alcala de Henares,
Madrid, Spain
Summary. Currently one of the most widely used
prosthetic materials in the repair of abdominal wall
defects, is expanded polytetrafluoroethylene (ePTFE). It
has been suggested that its behavior with respect to the
reparative process may depend on its structure. The aim
of the present study was to evaluate the effect of the
structure of 3 ePTFE prostheses on the scarring process
in an abdominal-wall-defect experimental model. The
prostheses employed were the Soft Tissue Patch (STP)
which is laminar in structure, Mycro Mesh (MM) which
is multilaminar with perforations, and the Dual Mesh
(OM) prosthesis which has one non-porous surface.
Abdominal wall defects (7x5cm) were created in 36
New Zealand rabbits and repaired using fragments of
STP, MM and OM. Follow-up periods were 14, 30, 60
and 90 days post-implant. At these times prostheses
were macroscopically examined for the presence of
infection and/or rejection and the formation of adhesions
to abdominal viscera. Specimens were also taken for
microscopic analysis (optical and scanning electron) and
for immunohistochemical analysis using the rabbit
macrophage-specific monoclonal antibody RAM-l1.
Labelled macrophage counts were performed at each
follow-up session. No cases of infection or rejection
were found. Loose adhesions between prosthesis and
underlying viscera were observed in 2 of the STP, 4 of
the MM and 2 of the OM implants. STP and OM
implants were progressively encapsulated by organized
connective tissue on both peritoneal and subcutaneous
surfaces. Cellular colonization was observed on both
STP surfaces and on the porous surface of the OM
although no more than a third of the biomaterial was
penetrated by cells in either case. Colonization was very
slight at prosthesis anchorage points. MM implants
differed only in the formation of connective tissue
bridges in perforated areas, and cellular infiltration in
interlaminar spaces. Macrophage response was similar in
the 3 prostheses with a reduction in RAM-l1 labelled
cells (p<0.05) between 14 and 90 days post-implant. We
conclude: a) the 3 types of PTFE prosthesis induced low
incidence of adhesion formation between biomaterial
and viscera; b) integration mechanisms of the 3
prostheses were similar and culminated with the
encapsulation of the PTFE by the neoformed tissue; c)
the macrophage response induced by the 3 prostheses
was similar to that of any reparative process in the
absence of biomaterial. Histol Histopathol 12, 683-690 (1997)
Key words: Polytetrafluoroethylene, PTFE prostheses,
Abdominal wall, Macrophages, Rabbits
DOI: 10.14670/HH-12.683
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