Open Journal of Urology, 2013, 3, 155-159 http://dx.doi.org/10.4236/oju.2013.33029 Published Online July 2013 (http://www.scirp.org/journal/oju) Dynamic Mechanical Properties of Tissue after Long-Term Implantation of Collagen and Polypropylene Meshes in Animal Models Michail G. Christodoulou 1 , Apostolos Papalois 2 , Dionysios Mouzakis 3 , Stefanos Zaoutsos 3 , Theodoros Kouranos 1 , Miltiadis Seferlis 1 , Charilaos Katsifotis 1 , Angelos Liapis 4 1 Department of Urology, General Hospital of Athens Polycliniki, Athens, Greece 2 Experimental Research Center ELPEN, Athens, Greece 3 Department of Mechanical Engineering, Technological Educational Institute of Larissa, Larissa, Greece 4 2nd Department of Obstetrics and Gynecology, Aretaieio Hospital, University of Athens, Athens, Greece Email: michailchristodoulou79@gmail.com, apapalois@elpen.gr, mouzakis@teilar.gr, szaoutsos@teilar.gr, koura1302@yahoo.gr, milsef@hotmail.com, ch.katsifotis@gmail.com, urodyn@aretaieio.uoa.gr Received May 20, 2013; revised June 18, 2013; accepted June 25, 2013 Copyright © 2013 Michail. G. Christodoulou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Purpose: Pelvic floor reconstructive surgery has grown significantly in recent years. A wide variety of available types of meshes exist but the safety and success has not been adequately proven. We sought to evaluate the effects on dy- namic biomechanical properties of tissue after long-term implantation of synthetic and biological grafts. Methods: A total of 96 New Zealand white female rabbits (approximately 3 kg) were used, 72 of which were surgically implanted with acellular, collagen mesh (n = 36) or nonabsorbable monofilament polypropylene mesh (n = 36). There was a no mesh-rupture of fascia group (n = 12) and a second, no-mesh, no-fascia rupture control group (n = 12). In the 59 rabbits, of 72 (13 died) tissue was harvested 3 months (n = 24), 6 months (n = 23) and 9 months (n = 12) later, while in the fas- cia rupture group, tissue was harvested 6 months later. Tissue samples (2 × 2 cm) underwent dynamic mechanical analysis (DMA) testing during which the dynamic rigidity and tissue damping capacities were measured. The statistical analysis was performed with General Linear Model with Tukeys post hoc testing (sPss v.17.0). Results: With respect to mesh type, the rabbit tissue in which polypropylene mesh was used showed the greatest dynamic rigidity. Those with biological mesh delivered the lowest rigidity results, while the two other groups had almost similar behavior. The meshes exhibited their highest relative dynamic tissue stiffening effect at 9 months. Conclusions: Biological mesh causes lower tissue rigidity, resulting in inferior mechanical response and thus seems to be inferior to polypropylene. Keywords: Biomechanical Properties; Tissue Stiffening; Collagen-Polypropylene Meshes 1. Introduction Disorders of the pelvic floor encompass a wide spectrum of interrelated clinical entities, including pelvic organ prolapse and incontinence. In addition to the physical symptoms that accompany these disorders, there is an important emotional effect, which includes social isola- tion, anxiety and depression [1]. Pelvic organ prolapse affects almost one third of premenopausal and approxi- mately one half of postmenopausal women [2,3]. Every year, approximately 135,000 women undergo surgery for urinary incontinence [4] and 225,000 for pelvic organ prolapse at a cost of greater than $1 billion per year in the United States [4,5]. Mechanical failure of the tissues in these anatomical areas is one of the causes [6] as the muscles and liga- ments of the pelvis cannot provide adequate support, for which sufficient connective tissue is paramount [7]. On the other hand, reconstructive procedures for the pelvic floor have increased exponentially in the past 20 years and the recent literature has shown increasing interest in the use of biological and synthetic mesh [8,9]. The prin- ciple behind using such grafts in reconstructive surgery is reinforcement of existing tissues with materials that are safe, biologically compatible and provide suitable ana- tomical and functional results. An ideal mesh must be inert, non-carcinogenic, resistant to tension, sterilizable, non-allergenic and non-inflammatory, unaffected by the body’s tissues and of course affordable [10]. In the effort Copyright © 2013 SciRes. OJU