[Reconstruction of the anterior wall of frontal sinus with biopolymers]. / Rekonstruktion der Stirnhöhlenvorderwand mit Biopolymeren.

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.

[Histological comparison of different biopolymers in osseous defects]. / Histologischer Vergleich unterschiedlicher Biopolymere im enossalen Defekt.

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, p < or = 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.

Contouring of cranial vault irregularities with hydroxyapatite cement: a clinical and experimental investigation.

The biocompatible hydroxyapatite cement (HAC) is a welcome alternative to the traditional use of autogenous bone for postoperative corrections of cranial vault irregularities. The authors performed experimental studies to show the safety and osseointegration capacity of HAC on animal models and confirm the osseous replacement without toxic reactions. The purpose of the current study was to analyze the clinical outcome after correction of secondary cranial vault irregularities with HAC. Twenty-one patients were treated for residual cranial frontal bone defects after craniotomy with HAC (Bone Source, Stryker Leibinger GmbH, D-79111 Freiburg, Germany). The average age was 38.5 years (range, 23-57 years). All of the patients were male. The average volume per patient was 53.83 g. The volume implanted ranged from 25 to 125 g; in all cases the dura was covered with bone. Irregularities resulted from sunken bone. The authors' clinical series demonstrates that a satisfactory and aesthetically pleasing result can be achieved in one surgical intervention in patients for surgical correction of postoperative cranial vault irregularities using HAC. It permits osseointegration, which makes it relatively resistant to infection. HAC is easy to apply and shape to suit individual needs. HAC is a welcome alternative to the traditional use of autogenous bone for postoperative corrections of cranial vault irregularities.

Cellular, histomorphologic, and clinical characteristics of a new octyl-2-cyanoacrylate skin adhesive.

Short-chained cyanoacrylates have been used for many years for topical skin closure. Toxic effects in cell culture of a new long-chained octyl-2-cyanoacrylate tissue adhesive are compared with those of short-chained ethyl-2- and butyl-2-cyanoacrylates. Two cellular tests were used: the agar overlay test and the MTT test. An in vitro test using copper plates coated with the three types of cyanoacrylates serves for evaluating the stability of polymerized skin adhesives. Bilateral neck skin incisions in Goettingen miniature pigs were glued on one side with Dermabond. On the other side, conventional sutures were applied. After the pigs were killed, the resulting skin samples were tested for the tensile strength of their wound stability. Samples of pig dermis were exemplarily and histomorphologically characterized. A clinical examination after submandibular lymph node dissection should examine the application in humans. Cell culture tests were used to show the toxic effects of the three cyanoacrylates. In a copper test, octyl-2-cyanoacrylate was more stabile than ethyl- and butyl-cyanoacrylates. Breaking strength was 30% lower 28 days after operation with the new product than with sutures. In electron microscopy, octyl-2-cyanoacrylate showed no disadvantages with regard to tissue regeneration and no histotoxicity. For plastic surgery, this new topical skin adhesive is a real alternative with attractive results, as compared with conventional suture.