title: [Tissue-engineered cartilage in a prefabricated microvascularized flap].
abstract: BACKGROUND
  In reconstructive surgery, the integration of tissue-engineered cartilage in a prefabricated free flap may make it possible to generate flaps combining a variety of tissue components to meet the special requirements of a particular defect. The aim of the present study was to establish the technique of prefabricating a microvascular free flap by implanting a vessel loop under a skin flap in a rabbit model. The second aim was to gather experience with prelaminating the flap with autologous tissue-engineered cartilage in terms of matrix development, inflammatory reaction and host-tissue interaction.
  
  
  METHODS
  The microvascular flap was created by implanting a vessel loop under a random pattern abdominal skin flap. The tissue-engineered cartilage constructs were made by isolating chondrocytes from auricular biopsies. Following a period of amplification, the cells were seeded onto a non-woven scaffold made of a hyaluronic acid derivative and cultivated for 2-3 weeks. One cell-biomaterial construct was placed beneath the prefabricated flap, and the others were placed subcutaneously under the abdominal skin and intermuscularly at the lower extremity. In addition, a biomaterial sample without cells was placed subcutaneously as a control. All implanted specimens were left in position for 6 or 12 weeks. After explantation, the specimens were examined by histological and immunohistological methods. The prefabricated flap was analyzed by angiography.
  
  
  RESULTS
  The prefabricated flaps showed a well-developed network of blood vessels formed by neovascularization between the implanted vessel loop and the original random-pattern blood supply. The tissue-engineered constructs remained stable in size and showed signs of tissue similar to hyaline cartilage, as evidenced by the expression of cartilage-specific collagen type II and proteoglycans. No hints of inflammatory reactions were observed.
  
  
  CONCLUSIONS
  These results show the potential of prefabricated flaps as custom-made flaps for reconstructive surgery in difficult circumstances, more or less independent of anatomical prerequisites. Cartilage tissue engineering provides a 3-dimensional structure with minimal donor-site morbidity.
authors.affiliation: Klinik und Poliklinik für Hals-Nasen-Ohren-Heilkunde der Universität Regensburg. rainer.staudenmaier@klinik.uni-regensburg.de
authors.forename: R
authors.initials: R
authors.lastname: Staudenmaier
authors.forename: N
authors.initials: N
authors.lastname: Miehle
authors.forename: N
authors.initials: N
authors.lastname: Kleinsasser
authors.forename: B
authors.initials: B
authors.lastname: Ziegelaar
authors.forename: M M
authors.initials: MM
authors.lastname: Wenzel
authors.forename: J
authors.initials: J
authors.lastname: Aigner
mesh_terms: D000818:Animals; D002356:Cartilage / Q000254:growth & development* / Q000473:pathology / Q000637:transplantation*; D018929:Cell Culture Techniques / Q000379:methods; D005549:Foreign-Body Reaction / Q000473:pathology*; D006084:Graft Rejection / Q000473:pathology; D011817:Rabbits; D019651:Plastic Surgery Procedures / Q000379:methods; D013524:Surgical Flaps / Q000009:adverse effects / Q000473:pathology*; D023822:Tissue Engineering / Q000379:methods*; D019737:Transplants / Q000009:adverse effects