Biocompatibility Testing of New Polymers in a Moving Implant Bed

Abstract

Total reconstruction of the auricle requires a skilful surgical technique and an appropriate material for the shape-supporting frame. Up to now, there is no such material apart from autologous rib cartilage. The combination of chronic microtraumatisation of adjacent tissue caused by the mobility of an implant bed such as the auricle and the foreign-body reaction to currently available artificial polymers frequently results in extrusion. In our animal model (rats), polymers of different elasticity were implanted in a moving implant bed to analyse differences in foreign-body reaction related to implant elasticity. The results were significantly better for a rather stiff control material (porous polyethylene). A contributing factor may be better fixation of the implant material by tissue ingrowth into its micropores.

An animal model in sheep for biocompatibility testing of biomaterials in cancellous bones

“…Biocompatibility of novel materials is often tested in less demanding animal models in the literature. Biological materials implanted into soft tissue, for example intramuscularly [ 9 , 16 , 29 ] or subcutaneously [ 12 , 14 , 17 , 33 ]), may answer questions pertaining to the local cellular and humoral reaction, but not to the degree of new bone formation, osteoinduction and -conduction. Even the local cellular degradation mechanisms may be different in soft and osseous tissue, since osteoclasts often involved in synthetic hydroxyapatite-based bone materials, are only present in bone but not subcutaneous or muscular tissues.…”

“…Furthermore, different implantation sites and methods have been used to examine biocompatibility issues. Among them are intra-peritoneal [ 13 ], subcutaneous [ 12 , 14 , 17 , 33 ], intraosseous such as in the mandible [ 19 , 27 ], femur [ 11 , 15 , 24 , 25 ]), tibia [ 18 , 20 , 21 , 23 , 26 , 30 ], cranial bone [ 28 , 31 ] and intramuscular [ 9 , 16 , 29 ] applications.…”