RECONSTRUCTIVE Anatomical and Technical Aspects of Harvesting the Auricle as a Neurovascular Facial Subunit Transplant in Humans Betul Gozel Ulusal, M.D. Background: Auricular transplants from cadaveric sources may be a viable al- Ali Engin Ulusal, M.D. ternative for difficult auricular reconstruction once immunologic problems are Jeng-Yee Lin, M.D. largely solved. The authors report on the neurovascular anatomy and technical Bien-Keem Tan, F.R.C.S.(Ed.) details of harvesting the auricle as a single facial subunit. Chin-Ho Wong, M.R.C.S.(Ed.) Methods: Nine auricles were studied in latex-injected (n ϭ 5) and fresh ca- Colin Song, F.R.C.S.(Ed.) daveric heads (n ϭ 4). In latex-injected heads, dissection in the neck and Fu-Chan Wei, M.D. auricular region and microdissection within the substance of the auricle were Taipei, Taiwan; and Singapore performed under loupe magnification. The arterial network was exposed and measurements were taken, including the size, length, and diameters of vessels. The number of branches supplying the entire auricle was noted. Methylene blue dye was injected into fresh cadaveric heads through the posterior auricular (n ϭ 2) or superficial temporal arteries (n ϭ 2) to assess the territory supplied by each arterial system. Results: Dye injected into the superficial temporal artery stained the upper two-thirds of the anterior and posterior auricular regions; all anterior cartilag- inous eminences, except the antitragus, were homogenously stained. Dye in- jected into the posterior auricular artery stained the lobule, posterior auricular skin, and the depressed anterior auricular regions, including the cavum con- chae, scapha, and triangular fossa. Neither the superficial temporal nor the posterior auricular arteries could adequately nourish the entire auricle as single pedicles. The auriculotemporal and great auricular nerves can be included in the transplant for sensation. The temporoparietal scalp can also be reliably included to meet reconstructive requirements. Conclusions: The auricle can be reliably elevated as a transplant when nour- ished by both the superficial temporal and posterior auricular arterial sys- tems. The external jugular vein and external carotid artery can therefore be used as the vascular pedicle for auricular transplantation. (Plast. Reconstr. Surg. 120: 1540, 2007.) he auricle is a specialized and complex fa- fibrocartilage, with characteristic eminences and cial subunit that is difficult to reconstruct depressions, which is lined with thin skin and Twhen severely deformed, such as by burn, connected to its surrounding parts and external trauma, or tumor ablation, or for congenital auditory meatus by ligaments, muscles, and fi- reasons. It is composed of a thin plate of yellow brous tissues. The most common current recon- structive alternative is the autogenous rib carti- From the Department of Plastic Surgery, Chang Gung Me- laginous framework.1 If the quality of skin in the morial Hospital, Chang Gung Medical College, Chang periauricular area is poor, however, or if there is Gung University, and the Department of Plastic Surgery, a shortage of autogenous cartilage because of Singapore General Hospital. previously failed operations, the reconstruction Received for publication March 27, 2006; accepted July 18, 1–3 2006. becomes even more difficult. Auricular trans- Presented at the 18th Annual Meeting of American Society plantation from cadaveric sources might be a for Reconstructive Microsurgery, January 14 through 17, valuable alternative for such patients. Recently, 2006, in Tucson, Arizona. following the first successful composite Copyright ©2007 by the American Society of Plastic Surgeons facial/scalp4 and auricle5 allotransplantations in DOI: 10.1097/01.prs.0000287992.28125.ce animal models, the first successful clinical case of 1540 www.PRSJournal.com Volume 120, Number 6 • Auricle Transplantation in Humans human auricular allotransplantation along with ously, immediately superficial to the galea. The the cephalocervical flap was reported by Jiang et parietal branch of the superficial temporal ar- al.6 Successful composite tissue allotransplanta- tery, the superficial temporal vein, and the au- tion requires competent microsurgical free tis- riculotemporal nerve were identified and in- sue transfer techniques, thorough knowledge of cluded in the transplant. These structures were the relevant anatomy, and stringent control of ligated cephalad unless a portion of scalp was immunologic allograft rejection.7–9 required. Dissection then continued anteriorly in The anatomy of the auricle as related to vari- a caudal direction; the frontal, middle temporal, ous flap elevations has been extensively zygomaticoorbital, and transverse facial branches studied.10–12 This anatomical study is the first to of the superficial temporal vessels were divided. explore the feasibility of harvesting the auricle Care was taken to include the neurovascular pedi- alone as a single neurovascular facial subunit cle and small anterior auricular branches along flap. the anterior portion of the auricle emanating from the superficial temporal artery and superfi- MATERIALS AND METHODS cial temporal vein. Immediately behind the neck A total of nine auricles, five latex-injected and of the mandible, at the level of the tragus, the four fresh cadaveric, were studied. For the latex superficial temporal artery and superficial tempo- injection study, the internal carotid artery was in- ral vein penetrated deep into the substance of the jected with 10% buffered formalin (to induce la- parotid gland. Because the inclusion of the pa- tex coagulation), followed by pigmented latex. rotid gland may not be desirable in auricular trans- The heads were then kept at 4°C in refrigerators plantation, the branches of the superficial tempo- for at least 24 hours. In latex-injected heads, dis- ral artery and superficial temporal vein to the section in the neck and auricular region and mi- parotid gland and masseter muscle were divided crodissection within the substance of the auricle and the gland was dissected away. Individual dis- were performed under loupe magnification. The sections of the superficial temporal artery and su- arterial network supplying the entire auricle was perficial temporal vein continued in different tis- exposed. Measurements were taken, including the sue planes. The superficial temporal vein united size, length, and diameters of vessels (with a Ver- with the internal maxillary vein to drain into the nier caliper). The number of vascular branches posterior facial vein within the parotid gland. The was also recorded. Injection studies with methyl- posterior facial vein ran inferiorly and divided into ene blue were performed in fresh cadaveric heads its anterior and posterior branches between the using either the posterior auricular artery (n ϭ 2) ramus of the mandible and the sternocleidomas- or the superficial temporal artery (n ϭ 2) to assess toid muscle. The anterior branch was ligated and the vascular territory supplied by each arterial sys- the posterior branch preserved as it was joined by tem in isolation. the posterior auricular vein to become the exter- nal jugular vein. The external jugular vein was Relevant Anatomy therefore the principal draining vessel of the au- ricular transplant. The posterior auricular vein The main arteries supplying the auricle are the was dissected toward the auricle. The posterior superficial temporal artery and the posterior au- auricular branch of the great auricular nerve was ricular artery, which arise from the external ca- found accompanying the posterior auricular vein rotid artery. Another branch from the occipital immediately beneath the auricular lobule. This artery provides a minor contribution to the auric- 10–13 nerve was divided and included in the transplant. ular circulation. Draining veins accompany For the arterial pedicle, the superficial tem- the corresponding arteries. Sensory innervation is poral artery was dissected toward the auricle. The provided by the great auricular and lesser occipital internal maxillary artery, a terminal branch of the nerves from the cervical plexus, the auriculotem- external carotid artery, was identified and divided poral branch of the mandibular nerve, and the 13 at the level of the mandibular neck. The posterior auricular branch of the vagus nerve. auricular artery was identified, beneath the digas- tric and stylohyoid muscles and opposite the apex Technique of Harvesting an Auricular of the styloid process, originating from the exter- Transplant nal carotid artery and dividing into auricular and A circular incision was placed to include a occipital branches between the auricular cartilage 1-cm skin island surrounding the auricle. Antero- and the mastoid process. The occipital branch was superiorly, the dissection continued subcutane- ligated and the auricular branch included in the 1541 Plastic and Reconstructive Surgery • November 2007 Fig. 1. The superficial temporal artery and its auricular branches Fig. 2. The vascular pedicle of the auricular flap formed from the (arrowheads). The largest branch, which crosses the helix, is uni- superficial temporal artery and the posterior auricular artery. a to formly located superior to the tragus (upper arrowhead). Note b, Posterior auricular artery length; c to d, superficial temporal that the superficial temporal artery does not give direct artery length, from the exit of the internal maxillary artery to the branches to the lobule. a, Facial region; b, temporal region;