The transverse myocutaneous gracilis flap is a safe, fast flap for reconstruction after benign and malignant breast disease. It combines a constant vascular pedicle with soft subcutaneous tissue that has breast-like characteristics.

Biomechanical properties of healing ruptures in the Achilles tendon of rabbits were examined after two, four, eight and 12 weeks. Treatment modalities were (n7): a) suture, b) fibrin-glue, c) non-surgical treatment. All animals received a functional aftertreatment consisting of a special orthotic support and free ambulation. For biomechanical testing a fixation-technique was applied that guaranteed intratendinous rupture. After two weeks, the tendons treated with fibrin glue showed better results (stiffness, maximum force to rupture, tensile stress to rupture) compared with the non-surgically treated group. The results for sutured tendons were in between those for the other groups. After four weeks, the results for sutured and for glued tendons were nearly equal and slightly better than the tendons in the non-surgical group. Late results revealed comparable biomechanical properties among all treatment groups and control tendons, suggesting our conclusion that non-surgical treatment is equal to repair using sutures or using fibrin glue as measured by stiffness and tensile stress.

The bridging of nerve gaps is still one of the major problems in peripheral nerve surgery. The present experiment describes our attempt to engineer different biologic nerve grafts in a rat sciatic nerve model: cultured isogenic Schwann cells were implanted into 2-cm autologous acellular nerve grafts or autologous predegenerated nerve grafts. Autologous nerve grafts and predegenerated or acellular nerve grafts without implanted Schwann cells served as controls. The regenerated nerves were assessed histologically and morphometrically after 6 weeks. Predegenerated grafts showed results superior in regard to axon count and histologic appearance in comparison to standard grafts and acellular grafts. The acellular nerve grafts showed the worst histologic picture, but axon counts were in the range of standard grafts. The implantation of Schwann cells did not yield significant improvements in any group. In conclusion, the status of activation of Schwann cells and the stadium of Wallerian degeneration in a nerve graft might be key factors for regeneration, rather than total number of Schwann cells. Predegenerated nerve grafts are therefore superior to standard grafts in the rat model. Acellular grafts are able to bridge nerve gaps of up to 2 cm in the rat model, but even the addition of cultivated Schwann cells did not lead to results as good as in the group with autologous nerve grafts.

Acellular muscle grafts can support axonal regeneration over short gaps. Due to the lack of viable Schwann cells in the grafts, failure of regeneration is evident with increasing gap lengths. To create a biological nerve conduit, Schwann cells were implanted into acellular muscle. The grafts were then incubated in vitro and assessed histologically and morphometrically. For cultivation of the Schwann cells, rat sciatic nerves were allowed to predegenerate to obtain a high cell yield. Rat gracilis muscles were harvested and made acellular by a liquid nitrogen treatment. After Schwann cell implantation, the muscles were incubated in vitro for 2, 5, and 7 days. S100-immunostaining, NGF, and N-cadherin, characterized the Schwann cells within the muscle. Viability was assessed by fluoresceine-fluorescence staining. Proliferation was determined by BrdU-DNA incorporation. Cell implantation did not to affect Schwann cell viability. Cells were seen throughout the entire length of the muscle basal lamina. They aligned and formed a cell column. Immunostained for S-100, implanted cells showed 100 percent staining. N-cadherin and NGF were expressed by all of the S-100 positive cells. Predegeneration is considered to be a highly efficacious method, if a high yield of activated Schwann cells is required. The successful implantation of the cells into an acellular muscle provides the possibility of a biologic conduit, offering the advantage of large basal lamina tubes serving as a pathway for regenerating axons. It also provides the beneficial effects of viable Schwann cells that produce neurotrophic and neurotropic factors to support axonal regeneration. Functional outcomes require evaluation in further in vivo studies.

In 105 rabbits the course of healing was examined at one, two, four, eight and 12 weeks (21 rabbits per group) after an experimental Achilles tendon rupture. The following treatment modalities were compared: A) primary functional treatment; B) operative functional treatment (resorbable suture); and C) operative functional treatment with fibrin glue. For the functional (after)-treatment a special orthosis was applied. A 7.5 MHz Ultrasound probe was used for ultrasonographic evaluation. The histological specimens were stained in Masson-Goldner and Azan technique. Collagen Type III was depicted immunhistologically. A semiquantitative fibrocyte count was performed. The histological results showed a smooth healing in the primary functional treatment group (A), reaching parallel orientation of collagen fibers at 12 weeks. In the suture group (B), a secondary gapping of the tendon stumps was detectable after one week as in all other groups. In the fibrin group (C), the fibrin was resorbed after four weeks without essential influence to the course of healing. At 12 weeks the histological evaluation in all groups showed approximately normal tendon pattern. Immunohistochemically, all groups showed cell-associated positive reactions for type-III collagen after one week with a maximum after two weeks. The semiquantitative fibrocyte count in the primary functional group showed a maximal number after one week. In the fibrin glue and suture groups the maximal number could be found after two weeks. Sonographically an increase in tendon thickness was detectable up to the fourth week in all groups. The secondary gapping of the tendon stumps in the suture group could also be detected sonographically. The echogenicity of the tendon during the course of healing showed increasing homogeneity and parallelism in all groups. At 12 weeks the echogenicity was comparable in all groups. The experiment suggests the equivalence of primary functional treatment to a combination of operative and functional therapy in Achilles tendon rupture.