Today reliable closure of complex wounds with exposed structures like bone, nerves, dura or larger vessels is achievable by means free microsurgical tissue transfer. The use of free flaps is associated with a donor site morbidity that can include functional muscle loss, nerve injury and scare formation. It is further limitated due to the reduced availability. Aim of the current study is the creation of an intrinsically vascularized fibrotic tissue flap on basis of an arteriovenous (AV) loop. Briefly, a vein is interposed between local artery and vein of the hind leg in rat and placed into a subcutaneous isolation chamber filled with an acellular matrix. Resulting from hemodynamic changes in the AV loop a three-dimensional vascular network is generated in the isolation chamber. Further fibrotic cells migrate into periphery of the chamber and a fibrotic tissue flap forms. This newly developed flap is nourished and transplantable as a free flap by the AV loop, resulting with only a minimal donor side morbidity.
At first, mechanisms of shear stress related angiogenesis, which are causal for the AV loop related development of a three-dimensional vascular network. In subproject 1 an allogenic vein graft, in which all cells express alkaline phosphatase (AP), is interposed between local vessels of an AP negative rat. Through this technique origin of the newly formed vessels can be identified. In subproject 2 the role of Connexin43 (Cx43) is evaluated. Recent studies point out the importance of Cx43 in shear stress related angiogenesis. A Cx43 inhibiting protein is added into the chamber and changes of the newly formed vessels are measured. Subproject 3 is designed to determine ideal matrix and accurate withdrawal time point to generate the most extensive and stable fibrotic tissue flap. Finally in subproject 4 the generated and intrinsically vascularized fibrotic tissue flap is transferred to a critical defect, in which scapular bone is exposed. Anastomosis are performed to the major cervical vessels.
-cross sectoral-Type of hazard:
rehabilitationDescription, key words:
microsurgical defect coverage, hemodynamic, vascularization, soft tissue flap