[Anomalies of the first branchial cleft - a review]. / Fehlbildungen der ersten Kiemenfurche - eine Übersicht.

BACKGROUND: Fistulas, sinus or cysts which trace back to anomalies of the first branchial cleft are seldom compared to lateral neck cysts and fistulas. For their accurate diagnosis and safe treatment special embryological and anatomical knowledge is necessary. MATERIAL AND METHODS: Embryology, anatomy, diagnosis and therapy are described and explained by 2 case studies in context to the current literature. RESULTS AND CONCLUSION: Sonography and contrast-enhanced radiological methods represent the fundamental pillar of the diagnosis. Therapeutically, the complete extirpation is the first choice. Surgeries on children, patients with extended fistulas and special cases of fistula routes require particular carefulness. In certain cases with pronounced findings and low levels of symptoms a "wait-and-see" strategy can be justified. Surgically, protection of the facial nerve and prevention of recurrences are the greatest challenge.

Atresia aural congênita unilateral / Unilateral congenital aural atresia

A atresia do canal auditivo externo (ACAE) é uma disordem congênita rara. A ACAE unilateral é de 3 a 6 vezes mais comum que a atresia bilateral. Tradicionalmente, não se acreditava que a ACAE unilateral fosse limitante ao desenvolvimento da linguagem da criança. No entanto, terapias recentes para perda auditiva têm demonstrado a importância da audição bilateral para um ótimo desenvolvimento da fala e da linguagem. Além disso, a audição bilateral é importante na localização de ruídos. Por isso exige diagnóstico rápido, aconselhamento genético e avaliação precoce da audição. Deve-se aconselhar adequadamente e encaminhar essas crianças e suas famílias para que possam ser avaliadas as opções de tratamento e indicações para intervenção. Avaliação clínica, audiológica e com estudo tomográfico de alta resolução do osso temporal é essencial para obter resultados satisfatórios e prevenir complicações na seleção de candidatos adequados para a cirurgia ou para avaliação do paciente, opções de tratamento, época de tratamento cirúrgico, critérios de seleção cirúrgica, técnicas cirúrgicas, complicações, prognóstico e controvérsias atuais relacionadas à atresia aural congênita serão discutidos.

Embryology and epidemiology of microtia.

The auricle derives from six hillocks arising from the first and second branchial arches. Different hillocks give rise to different parts of the pinna. In the course of embryonic development, the auricle migrates postero-cranially as the mandible enlarges. Auricular malformations, such as microtia, are thought to be related to cell death of the first and second arch derivatives. The prevalence and characteristics of microtia vary in different populations. The prevalence ranges from 0.83 to 17.4 per 10,000. Microtia is more common in males, and right-sided dominance varies from 57 to 67%. The prevalence of aural atresia or stenosis varies from 55 to 93%. Microtia has been associated with numerous risk factors including race and gender. Genetic factors are likely to have an effect at least in some patients with microtia.

Defects of the external auditory canal: a new reconstruction technique.

This report describes the clinical and radiographic findings together with surgical management of temporomandibular joint contents herniation through the tympanic plate of the external auditory canal. Two patients are reported. A review of the literature is presented, including a brief discussion of the embryological development of the external auditory canal. Excluding infection, trauma or neoplasm, the defect in the tympanic plate of the external auditory canal represents a developmental aberration with failure of the foramen of Huschke to close during development. A pre-auricular approach with insertion and fixation of an onlay polyethylene implant to prevent prolapse of the peri-articular tissues into the ear canal is presented and described.

Periauricular cysts and sinuses.

Periauricular cysts, sinuses, and fistulas occur commonly in the pediatric population. They arise from developmental defects of the first branchial cleft and first branchial arch. In most instances the diagnosis and management of these conditions are straightforward, but exceptional presentations sometimes occur. Failure to recognize these unusual cases may result in inadequate treatment and subsequent recurrence, and even if the correct diagnosis is made, surgical management of these lesions may be complicated. A series of 15 cases of periauricular congenital lesions is reviewed, of which three cases illustrating a diagnostic or surgical challenge are presented. The embryology, presentation, and management of these anomalies are discussed. This is one of the largest series of first branchial cleft anomalies reported in the literature, and our paper uniquely discusses first branchial cleft anomalies and preauricular sinuses together, with an emphasis on the surgical management of facial nerve, external ear, and middle ear involvement.

Efectos de la gentamicina y kanamicina a dosis terapéuticas en el desarrollo del oído interno de la ratas / Gentamicin and Kanamicin effects on the development of the internal ear in rat

Los aminoglucósidos son antibióticos de acción bactericida a nivel ribosomal en la subunidad 30s, en donde se inhiben la síntesis proteica y disminuye la fidelidad de la traslación del RNAm. La ototoxicidad es el resultado de la destrucción progresiva de células sensoriales a nivel coclear y vestibular. El objetivo del estudio fue determinar los cambios histopatológicos en el desarrollo del oído interno en embriones de rata al administrarse gentamicina a dosis de 3.5 mg/Kg/día y 7 mg/Kg/día por 21 días y kanamicina a dosis de 7 mg/Kg/día y 15 mg/Kg/día por 21 días. Los productos fueron sacrificados a los 7 y 14 días de gestación e inmediatamente después de termianr el período de gestación. Se observó un detenimiento del desarrollo y crecimiento de las estructuras del oído interno. La gentamicina causó mayores daños a nivel vestibular y la kanamicina a nivel coclear. Los principales cambios cocleares encontrados fueron degeneración de las células externas e internas hacía la porción basal, así como colapso de las rampas vestibular y timpánica. Los principales cambios vestibulares fueron: falta de desarrollo de la cresta ampular, ausencia de células ciliadas e hipodesarrollo de canales semicirculares

Histological examination of the auricular cartilage and pseudocyst of the auricle.

In our histological examination of 42 ears (auricles) which were taken from 18 fetus and three adults, the intracartilaginous fibrous tissue with blood vessels and lymphatics were found in 12 ears and interruption of the auricular cartilage in 22 ears. The intracartilaginous connective tissue with blood vessels and lymphatics were linked together with the connective tissue outside the auricular cartilage in other sections. These findings support the hypothesis of congenital embryonic dysplasia as the origin of the formation of pseudocyst of the auricle.

Early ossification within the human fetal otic capsule: morphological and microanalytical findings.

Besides the use of conventional techniques such as light and polarization microscopy, the present paper proposes the combined use of transmission electron microscopy, secondary and backscattered electron imaging, energy dispersive X-ray analysis and computed tomography for the diagnostic evaluation of ear pathology in the human fetus. These methods were used to revisit the primary calcification front of the fetal otic capsule between 16 and 23 weeks gestational age. Ultramicroscopic evaluation demonstrates similar fetal bone formation to that found in other bones of the human fetus. The formation of the endosteal and periosteal layers is a typical example of early intra-membranous ossification. The enchondral layer is made up of fibrillar bone, laid down around the calcified cartilage remnants. Microchemical analysis indicates a significantly higher Ca/P ratio in the endochondral layer with respect to the endosteum and periosteum. The consequences of a lower Ca/P ratio in the endosteal layer are discussed in view of calcium homeostasis and inner ear function.

Congenital cholesteatomas in children: an embryologic correlation.

The clinical findings in 37 children with congenital cholesteatoma of the middle ear, 17 of which have not been previously reported, are presented. Clinical findings and surgical observations are correlated with recent developmental studies. It is hypothesized that congenital cholesteatoma may originate from an epidermoid formation, which has been identified in the anterior superior lateral tympanic cavity adjacent to the anterior annulus during fetal development, and which normally is present early in development, involuting by 33 weeks' gestation. It is proposed that the epidermoid formation may not always involute, and could serve as an embryologic anlage of congenital cholesteatomas.

Origin of congenital cholesteatoma from a normally occurring epidermoid rest in the developing middle ear.

The sites of involvement of congenital cholesteatoma, a lesion which has recently become more frequently recognized, are reviewed from literature sources. There is a propensity for its occurrence, especially when small, in the anterior superior part of the middle ear. The same situation is the precise location of an epidermoid cell rest, the epidermoid formation (EF). This is seen in most fetal ears at the junction of the Eustachian tube with the middle ear near the anterior limb of the tympanic ring, until 33 weeks gestation, when it disappears. Its origin is traced to early fetal life from the ectoderm of the first branchial groove. In embryonic and early in fetal life it seems to act as an organizer in the development of the tympanic membrane and middle ear. It is likely that congenital cholesteatoma is derived from the EF by its continued growth instead of regression. Congenital cholesteatomas show a thinner and flatter matrix than acquired cholesteatomas, probably because the former are most frequently 'closed' and therefore subject to pressure effects from the keratin within the cyst. 'Open' forms also occur in smaller numbers. It is possible that a screening program for congenital cholesteatoma in infants might reduce the incidence of the severe, extended form of the disease.

Role of the tympanic ring in the pathogenesis of congenital cholesteatoma.

Topographic study of congenital cholesteatomas revealed that the majority of these congenital epidermal cysts occur near the tympanic isthmus of the middle ear. Since this is the junction of the first and second brachial arch, the origin of the cholesteatoma could be linked to the migration of the external canal ectoderm into the middle ear at the early stage of development. Embryologic study showed that the tympanic ring plays an important role in limiting the medial extent of the external canal to the level of the tympanic annulus. Migration of the ectodermal tissue into the middle ear beyond the annulus is likely to be caused by the failure of this inhibitory function of the tympanic ring. Microscopic sections of human fetuses were studied to determine the developmental relationships between the external canal ectoderm and the tympanic ring. A section from a 161/2-week fetus showed significant papillary ectodermal tissue projection into the mesenchyme near the tympanic isthmus, while the tympanic ring was absent in that site. Anatomical distance between the tympanic ring and the internal auditory canal is extremely short in these fetuses. This is suggestive of the source of petrous cholesteatomas from the canal ectodermal migration. These observations form the basis of the author's theory that the pathogenesis of congenital cholesteatomas is caused by migration of external canal tissue into the tympanic isthmus or into the petrous bone as a result of developmental error in which the advancing external canal ectoderm failed to receive stop signal of the tympanic ring that contains the ectoderm at the annular plane.

[The fistula of the first branchial cleft A critical presentation of its pathogenesis and its clinical and surgical problems. A description of one case combined with a fistula auris congenita (author's transl)]. / Die Ohr-Hals-Fistel Kritische Darstellung ihrer Pathogenese sowie ihrer klinischen und chirurgischen Problematik Beschreibung eines Falles mit gleichzeitiger Fistula auris congenita

A case of congenital fistula of the first branchial cleft (Ohr-Hals-Fistel) is presented. Based on the previously published cases the anatomical and clinical aspects of the disease are summed up. Pathogenesis is discussed on the underlying principles of embryological basic research, centering on Hochstetter's "Entwicklungsgeschichte der Ohrmuschel und des äusseren Gehörganges des Menschen" (1948), a publication that is hardly known. Some hypotheses on the genesis of the fistula of the first branchial cleft are criticised and a new hypothesis is developed to the effect that the fistula is caused by a disturbance in the development of the external ear channel. A few critical remarks are added concerning the discussion on the genesis of fistula auris congenita.