Histopathological and audiological effects of mechanical trauma associated with the placement of an intracochlear electrode, and the benefit of corticosteroid infusion: prospective animal study.

OBJECTIVE: This study aimed to present the histopathological and audiological effects of mechanical trauma associated with the placement of a model electrode in the scala tympani in rats, and the effects of continuous topical corticosteroid application. METHOD: The study comprised three groups of rats. The round window membrane was perforated in all three groups and a model electrode was inserted in the round window. Group one received no further treatments. Groups two and three also had an intrathecal microcatheter compatible with a mini-osmotic pump inserted; in group two this was used to release normal saline and in group three the pump released 400 µg/ml dexamethasone. RESULTS: Dexamethasone infusion given after implantation of the intracochlear model electrode was more effective for preventing hearing loss than the administration of just one dose of dexamethasone. CONCLUSION: The findings suggest that continuous dexamethasone infusion is beneficial for preventing the loss of hair cells and neurons associated with early and late periods of intracochlear electrode trauma.

Short-term laryngeal electromyography and histopathological findings after primary reconstruction of the inferior laryngeal nerve in rabbits: prospective study.

INTRODUCTION: The recurrent laryngeal nerve can be injured during surgery. This study investigated recurrent laryngeal nerve reinnervation. OBJECTIVE: To study the short-term effects of primary anastomosis of the recurrent laryngeal nerve, by laryngeal electromyography and histopathological analysis, in a rabbit model. METHOD: Twenty Zealand rabbits underwent either right recurrent laryngeal nerve (1) transection with excision of 1 cm or (2) transection and end-to-end primary anastomosis. Vocal fold movements, laryngeal electromyography results and histological changes were recorded. RESULTS: Vocal fold analysis showed a paramedian vocal fold in both groups, with perceptible vibratory movements in group two. Electromyography revealed total denervation potentials in group one, but denervation and regeneration signs in group two. Histopathologically, hyperkeratosis and parakeratosis of the vocal fold mucosa were seen in group one, and signs of parakeratosis and hyperplasia in group two. CONCLUSION: Even under ideal conditions for primary recurrent laryngeal nerve anastomosis, a return to normal muscle function is unlikely. However, such anastomosis prevents muscle atrophy, and should be performed as soon as possible. The degree of nerve recovery is associated with the number, amplitude and myelination level of fibrils returning to the original motor end-plaque.

Pharyngeal foreign body in a child persisting for three years.

Foreign body ingestions are common in children. They can pose a diagnostic problem if the foreign body is embedded in the soft tissues of pharynx. A 4 year old girl presented with halitosis for two years. A pharyngeal foreign body, a metallic ring, was seen on lateral radiographs of the neck. The foreign body was removed under general anaesthesia. A completely embedded pharyngeal foreign body should be considered in cases presenting with halitosis.

[Hereditary deafness in Turkey. Initial results]. / Hereditäre Schwerhörigkeit in der Türkei. Erste Ergebnisse.

The authors describe a study in progress to identify Turkish families with hereditary hearing loss and isolate possible responsible disease genes. Due to extreme genetic heterogeneity and limited audiological differentiation of hereditary hearing loss, it is necessary to identify large or small families from genetic isolates to locate loci responsible for hearing loss on a chromosome. To accomplish this goal, the medical records of 3800 children were examined at the ENT Clinic of Ege University between 1975 and 1994. All were suspected of having various hearing impairments. Additionally, students from two schools for the hearing impaired in Izmir and Eskisehir, Turkey were examined. To date, 16 families with syndromal deafness and 55 families with non-syndromal hereditary hearing loss involving two or more affected individuals have been identified and categorized according to the mode of inheritance. The majority (66%) of the non-syndromal families showed an autosomal recessive pattern, 29% an autosomal dominant inheritance and 5% an X-linked mode of inheritance. In the study presented there has been a predominance of affected males versus females and the consanguinity rate was 22%.

A second middle eastern kindred with autosomal recessive non-syndromic hearing loss segregates DFNB9.

A second kindred has been identified which supports the previously reported location of DFNB9. Linkage has been established to markers closely linked to DFNB9 which is located on 2p22-p23. The hearing impaired individuals in this highly consanguineous kindred from Eastern Turkey have prelingual profound hearing loss which affects all frequencies. A genetic map of the 2p22-p23 region where DFNB9 resides was generated using marker genotypes available from the CEPH database. All markers were placed on this genetic map using a likelihood ratio criterion of 1000:1. This map suggests that the region for DFNB9 is less than 1.08 cM, 95% confidence interval (0-2.59 cM).