Talk:Hearing - Outer Ear Development

2010

Ear reconstruction through tissue engineering

Adv Otorhinolaryngol. 2010;68:108-19. Epub 2010 May 3.

Haisch A.

Department of Otorhinolaryngology, Head and Neck Surgery Campus Benjamin Franklin, Charité University Medicine Berlin, Berlin, Germany. andreas.haisch@charite.de Abstract For decades, reconstructive surgery of the auricle has presented a challenge to surgeons. An immense number of publications now document the efforts to develop and improve techniques designed to provide reasonable shape and functionality. Since the early 1990s, tissue engineering has become increasingly popular in the field of reconstructive surgery. In particular, when an in-vitro-manufactured auricular-shaped cartilage implant was implanted on the back of a nude mouse, reconstructive surgeons were intrigued and patients' expectations were raised. However, almost 20 years after tissue engineering was defined by Langer and Vacanti [Science 1993;260:920-926] as: 'an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ', only single case reports have been published. These reports detail the clinical application of in-vitro-manufactured cartilage for reconstructive procedures in the head and neck. The present article describes the fundamentals and potential of tissue engineering in reconstructive surgery of the auricle, and highlights the limitations that prevent its current clinical application.

Combined reconstruction of congenital auricular atresia and severe microtia

Adv Otorhinolaryngol. 2010;68:95-107. Epub 2010 May 3.

Siegert R.

Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Prosper Hospital, Ruhr University Bochum, Recklinghausen, Germany. profsiegert@web.de Abstract OBJECTIVES: Due to their embryological development, auricular atresia and severe microtia are, in most cases, combined malformations. The aims of this study were firstly to develop a surgical technique for combined esthetic and functional reconstruction with a minimum of operations and secondly to evaluate its results.

STUDY DESIGN: Prospective clinical evaluation.

PATIENTS AND METHODS: Fifty-two patients with third-degree microtia and congenital aural atresia with a sound-conducting block of about 50 dB were treated. In the first operation, autogenous cartilage was harvested, and the auricular framework was fabricated and implanted. In addition, the tympanic membrane and the external ear canal were prefabricated, and stored in a subcutaneous pocket. In the second step, the elevation of the new framework was combined with the operation for atresia, utilizing the prefabricated tympanic membrane and external ear canal. In the third step, the cavum concha was deepened, and the external ear canal was opened and covered with a skin graft.

RESULTS: In total, 76% of the patients had a final conductive hearing loss of 30 dB or less. No restenosis of the new external ear canal was observed. The esthetic results of the constructed auricles are shown in this report.

CONCLUSION: With this combination of plastic surgery for the auricle and functional surgery for the middle ear, no additional operations are necessary and the prefabrication of the external ear canal and the tympanic membrane gives stable and reliable results. This combined technique offers the best chance of optimal esthetic and functional rehabilitation for patients with these malformations.

Morphology of the human tympanic membrane annulus

Otolaryngol Head Neck Surg. 2010 May;142(5):682-7.

Kassem F, Ophir D, Bernheim J, Berger G.

Department of Otolaryngology-Head and Neck Surgery, Meir Medical Center, Kfar Saba, Israel. firas67@hotmail.com Abstract OBJECTIVE: To study the full panoramic view with figuring of the morphology and topography of the human tympanic annulus.

STUDY DESIGN: Postmortem material analysis.

SETTING: University-affiliated hospital.

SUBJECTS AND METHODS: Twenty-three single, normal human adult tympanic membranes were completely extracted from formalin-fixed temporal bones. They were faced medially and placed at the same level of a graph paper mounted on a board. High-quality images of the tissue preparations were taken, and computer-aided measurements of the annular caliber were calculated at nine reference points. The 6 o'clock direction served as a midpoint, and another four reference points were set anteriorly and posteriorly in clockwise and counterclockwise directions.

RESULTS: The annulus has a horseshoe-like shape with a small part absent above the neck of the malleus. The maximal mean caliber at the manubrial axis (6 o'clock direction) was 748 +/- 201 mum. The annulus gradually thins out almost symmetrically anteriorly and posteriorly, until it reaches about 15 percent of the maximal caliber at its end points (152 +/- 87 and 113 +/- 42 mum, respectively). Significant differences were found between adjacent reference points on both anterior and posterior sides.

CONCLUSIONS: The annulus has a horseshoe-like shape and gradually thins out almost symmetrically, reaching anteriorly and posteriorly about 15 percent of the maximal caliber at the manubrial axis. These new data may provide guidance in transcanal middle ear exploration and suggest the possibility of varied functions attributable to the annulus regarding middle ear sound transmission and TM vibratory properties. The data may contribute to understanding the development of marginal perforations and posterior superior retraction pockets.

2009

Craniofacial Microsomia Overview

Heike CL, Hing AV. In: Pagon RA, Bird TC, Dolan CR, Stephens K, editors. GeneReviews [Internet]. Seattle (WA): University of Washington, Seattle; 1993-. 2009 Mar 19.

Excerpt Disease characteristics. Craniofacial microsomia (CFM) includes a spectrum of malformations primarily involving structures derived from the first and second branchial arches. Findings include facial asymmetry resulting from maxillary and/or mandibular hypoplasia; preauricular or facial tags; ear malformations that can include microtia (hypoplasia of the external ear), anotia (absence of the external ear), or aural atresia (absence of the external ear canal); and hearing loss. Severity can range from subtle facial asymmetry with a small skin tag in front of an otherwise normal-appearing ear to bilateral involvement (typically asymmetric), microtia/anotia with atresia of the ear canals, microphthalmia, and respiratory compromise from severe mandibular hypoplasia. Other craniofacial malformations including cleft lip and/or palate can be seen. Non-craniofacial malformations, especially vertebral, cardiac, and limb, can be seen. Diagnosis/testing. The diagnosis of CFM is based on clinical findings. Genetic counseling. CFM most frequently occurs as a simplex case (i.e., occurrence in a single individual in a family) with unknown etiology; recurrence risks are empiric. If an individual with CFM is found to have an inherited or de novo chromosome abnormality, genetic counseling for that condition is indicated. Occasional autosomal dominant or autosomal recessive inheritance is observed. If a proband has CFM and no reported family history of CFM, the risk to sibs is two to three percent; this may be an underestimate because of the difficulty of obtaining an accurate family history for some of the subtle features of CFM. Management. Treatment of manifestations: For optimal outcome children with CFM require timely and coordinated assessments and interventions. Ideally, children should be managed by an experienced multidisciplinary craniofacial team. The goals of treatment for CFM are to assure adequate respiratory support and feeding in infants with severe facial malformations, maximize hearing and communication, improve facial symmetry, and optimize dental occlusion. Treatment is age-dependent, with time-sensitive interventions at appropriate stages of craniofacial growth and development. Copyright © 1993-2010, University of Washington, Seattle. All rights reserved.

PMID: 20301754 http://www.ncbi.nlm.nih.gov/pubmed/20301754

Congenital upper auricular detachment: Report of two unusual cases

Indian J Plast Surg. 2009 Jul;42(2):265-8.

Agarwal P.

Plastic Surgery Unit, Department of Surgery, Netaji Subhash Chandra Bose Government Medical College, Jabalpur-482 003, MP, India. Abstract Two unusual cases of congenital bilateral ear deformity have been presented. The deformity is characterized by upper auricular detachment on the right side with anotia on the left side in the first case and upper auricular detachment on the left side with normal ear on the right side in the second case. An attempt has been made to correlate the presented deformity with the embryological - foetal development of the auricle. Satisfactory correction can be obtained by repositioning the auricle back in to its normal position.

PMID: 20368874 http://www.ncbi.nlm.nih.gov/pubmed/20368874

http://www.ijps.org/article.asp?issn=0970-0358;year=2009;volume=42;issue=2;spage=265;epage=268;aulast=Agarwal

2008

Mutation in the human homeobox gene NKX5-3 causes an oculo-auricular syndrome

Am J Hum Genet. 2008 May;82(5):1178-84.

Schorderet DF, Nichini O, Boisset G, Polok B, Tiab L, Mayeur H, Raji B, de la Houssaye G, Abitbol MM, Munier FL.

Institut de Recherche en Ophtalmologie, 1950 Sion, Switzerland. daniel.schorderet@irovision.ch Abstract Several dysmorphic syndromes affect the development of both the eye and the ear, but only a few are restricted to the eye and the external ear. We describe a developmental defect affecting the eye and the external ear in three members of a consanguineous family. This syndrome is characterized by ophthalmic anomalies (microcornea, microphthalmia, anterior-segment dysgenesis, cataract, coloboma of various parts of the eye, abnormalities of the retinal pigment epithelium, and rod-cone dystrophy) and a particular cleft ear lobule. Linkage analysis and mutation screening revealed in the first exon of the NKX5-3 gene a homozygous 26 nucleotide deletion, generating a truncating protein that lacked the complete homeodomain. Morpholino knockdown expression of the zebrafish nkx5-3 induced microphthalmia and disorganization of the developing retina, thus confirming that this gene represents an additional member implicated in axial patterning of the retina.

PMID: 18423520

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2427260

http://www.elsevier.com/wps/find/authorsview.authors/supplementalterms1.0