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The two biopolymers Ethisorb and its modification Ethisorb Rapid were implanted in 80 defects of the anterior wall of frontal sinus in 20 Goettingen minipigs to analyze density of trabecula (Mann-Whtiney-Rank-Sum-Test), degradation of biopolymers and histomorphology. To optimate bone regeneration, particular resorbable membranes and autogenic spongiosa chips were used. The animals were killed after six, 12, 26 and 52 weeks and then postoperative undecalcified bone cuts were obtained. All in all, with Ethisorb contrary to Ethisorb Rapid a faster biopolymer resorption in the 12th and 26th week with a statistically significant greater density of trabecula could be observed. The use of resorbable membranes and autogenic spongiosa chips led, in comparison to simple implantation of biopolymers, to significantly greater densities of trabecula. The use of Ethisorb contrary to Ethisorb Rapid with membranes led to a Guided Bone Regeneration (GBR) with persistence of membrane particles to week 12 and 26. By mixing biopolymers with autogenic spongiosa chips a multiloculated bone regeneration could be generated. For Ethisorb with resorbable membranes and autogenic spongiosa chips the best bone regeneration with highest densities of trabecula could be recognized.

The goal of this animal study in Goettingen minipigs was to compare Ethisorb with its modification Ethisorb Rapid where the hydrolytic degradation process has started, with respect to degradation and bony substitution qualitites. For comparison, both biopolymers were implanted with and without addition of autogenic spongiosa chips in comparison with blank defects in metaphysis of the tibia. The animals were killed after six, 12, 26 and 52 weeks. Undecalcified bone cuts were obtained and subjected to a histomorphometric and histomorphological analysis. All in all, with increasing time after implantation a continuous decrease of the density of trabecula could be observed. In comparison to Ethisorb Rapid and blank defects, the implantation of the slowly degrading but quickly resorbing Ethisorb led to statistically significantly higher densities of trabecula (Tuckey Test, por = 0.05) and to best bone regeneration. In contrast to this, Ethisorb Rapid could be degraded more quickly but resorbed more slowly. In the polarizing microscope, Ethisorb could still be detected after 12 weeks of implantation. Ethisorb Rapid could still be detected after 26 weeks of implantation. To conclude, Ethisorb proved to be a suitable scaffold for autogenic spongiosa-chips in critical-size defects of the tibia so that a multiloculated bone regeneration could be obtained.