Shrinkage and biomechanical evaluation of lightweight synthetics in a rabbit model for primary fascial repair

Abstract

Introduction and hypothesis: The experiment evaluated different lightweights (<32 g/m(2)) in terms of shrinkage and biomechanics.

Methods: PP-8 (polypropylene of 7.6 g/m(2)), PP-s (PP-8 with absorbable sheets), PP-32 (PP with absorbable fibers; 32.0 g/m(2)) and polyvinylidinefluoride (PVDF; 24.9 g/m(2)) augmented primary sutured repairs of the anterior abdominal wall in a total of 40 rabbits. Rabbits were implanted by only one type of mesh at four abdominal sites. After 7, 14, 30, 60 and 120 days, 2 rabbits were sacrificed per group. Three additional unoperated rabbits were used as controls. Shrinkage and uni-axial tensiometry were evaluated.

Results: PP-s implants wrinkled in 70%. PP-32 did not shrink whereas PP-8 and PVDF shrank by 20%. Explants were as strong as the controls; however, they differed in compliance. At lower stress, the tested materials were equally stiff.

Conclusions: The biomechanical behaviour of the tested lightweights does not mimic that of native controls. Weight reduction does not prevent shrinkage.