In vivo perfusion analysis of normal and dysplastic ears and its implication on total auricular reconstruction

Abstract

During the first stage of total auricular reconstruction with autologous rib cartilage, according to Nagata, the cartilage framework is placed in a subcutaneous pocket. Its posterior skin flap is relatively large and can be prepared with or without a subcutaneous pedicle. This represents the crucial part of the procedure, as impaired healing and infection can occur due to low perfusion. Nothing was known about the blood supply of ear remnants or flap perfusion during reconstruction. It was not clear whether the preservation of the additional subcutaneous pedicle secures high blood supply. We used laser fluorescence angiography with indocyanine green dye for anatomical and functional perfusion studies in eight normal ears. Subsequently the anatomical and functional vessel architecture of 18 dysplastic ears was investigated. Finally, five patients each were operated on with or without subcutaneous pedicle during auricular reconstruction and intraoperatively monitored with laser fluorescence angiography. We showed that the vessel structure of normal ears detected by fluorescence angiography is equivalent to anatomical preparations. The surrounding skin in high grade microtia remnants is biphasically perfused by deep perforators and by the cutaneous vessel network. The preservation of the subcutaneous pedicle during auricular reconstruction leads to significantly better perfusion of the posterior skin flap. No signs of critical perfusion or complications were observed in these patients. We present the feasibility of laser fluorescence angiography to simultaneously gain anatomical and functional data about skin blood supply. The first anatomical and functional description of blood supply of ear remnants in third grade microtia is given. Functional data of skin flap perfusion during and after complete ear reconstruction were evaluated. The present study shows that the subcutaneous pedicle of Nagata's procedure is of great importance for success of the first stage operation as it prevents impaired wound healing. In contrast, patients without a subcutaneous pedicle had a broad spectrum of reduced perfusion and therefore some had complications.