Ear Transplantation

, Bahar Bassiri Gharb¹ and Selman H. Altuntas²

(1)

Department of Plastic Surgery, Cleveland Clinic, Cleveland, OH, USA

(2)

Department of Plastic Reconstructive and Aesthetic Surgery, Suleyman Demirel University Medical Faculty, Isparta, Turkey

Abstract

In this chapter we describe the technical aspects of orthotopic composite external ear allotransplantation under low dose immunosuppressive monotherapy in a rat model. We demonstrate that it is feasible to elevate and transplant this composite allograft in rats as a flap based on the common carotid artery. A tapered dose of cyclosporine A from 16 to 2 mg/kg allows indefinite maintenance of the allograft and survival across a fully mismatched major histocompatibility complex barrier. This model is reliable and reproducible and has the potential to be used for future immunologic studies to investigate strategies in preventing rejection or to induce transplantation tolerance. One disadvantage of this model is the small dimension of the allograft which makes the clinical monitoring difficult and does not provide sufficient tissue for multiple sequential biopsies.

Keywords

Vascularized composite allotransplantationEar transplantationFace transplantationExperimental modelsRat

Introduction

Severe deformities of the ear could be caused by burns, trauma, cancer or alternatively are due to congenital reasons. The external ear has a pliable three-dimensional structure, with a complex morphology; therefore, it cannot be easily duplicated. Alternatives for auricular reconstruction include autologous rib cartilage graft, prosthetic implants, or alloplastic frameworks. In autologous reconstructions the outcome is greatly influenced by the condition and availability of the local tissues, and a perfect result is difficult to achieve. The implantable frameworks are associated with high complication and extrusion rates. Because of advances in transplantation immunology, we have witnessed new clinical applications for vascularized composite allografts. The research of effective strategies to induce tolerance demands the availability of a variety of models which could reproduce the different composite allografts. With this in mind, we explored the feasibility and technical aspects of harvesting and transplanting the external ear under low dose immunosuppressive monotherapy.

Surgical Technique

Inbred ACI (RT1^a) and Lewis (RT1¹), male rats weighing 250–300 g and 12–16 weeks old were used as donors and recipients, respectively. Anesthesia was induced and maintained with 0.15 ml/100 g ketamine cocktail (30 mg/kg Ketamine +6 mg/kg Xylazine +1 mg/kg Acepromazine) injected in the subcutaneous tissue of the posterior neck. The hair on the preauricular and neck region was shaved and the skin was cleansed with povidone-iodine solution.

Preparation of the Donor

The outline of the flap was designed marking the cranial midline and the cervical midline. Two lines perpendicular to the previous were drawn 0.8 cm buccal and caudal to the ear.

The cervical incision was performed according to the marking through the skin, subcutaneous tissue and platysma muscle. The subplatysmal dissection started from the cervical midline and proceeded laterally. The sublingual and submandibular glands were encountered and excised after cauterization of their vascular pedicle arising from the facial artery and vein (Fig. 46.1a

Only gold members can continue reading. Log In or Register to continue