Luiz Lavinsky

Prevalência de perda auditiva em recém-nascidos de muito baixo peso

Objectives: to evaluate the prevalence of hearing alterations in very low birth weight patients in the Neonatal Intensive Care Unit of the Hospital de Clinicas de Porto Alegre and to study the variables that can be related to alterations of the hearing acuity.

Otitis media in children: seasonal changes and socioeconomic level.

OBJECTIVE Our objective was to determine the frequency of otitis media (OM) in relation to socioeconomic and seasonal factors in a city in southern Brazil. METHODS A prospective, longitudinal study was carried out with a 3-4-year-old cohort of children randomly selected in schools serving populations of higher socioeconomic status (AB; monthly family income >10 minimum wages, US

CT-Scan sheep and human inner ear morphometric comparison.

1000) or lower socioeconomic status (CD; monthly family income < or = 3 minimum wages, US

Surgical Treatment of Vertigo by Utriculostomy: an Experimental Study in Sheep

300). The children were assessed in the fall, winter, and spring of 1997 using otoscopy and tympanometry. RESULTS Among 156 children who finished the study, 53.8% belonged to socioeconomic group CD. Otoscopy suggested chronic suppurative otitis media (OM) (tympanic membrane perforation or otorrhea) in <6% of children in the CD group, with no seasonal variation. Alterations suggesting secretory otitis media (SOM) were significantly more frequent in the CD group (P< or = 0.001), with a peak in the winter. The prevalence of SOM on otoscopy was: fall (20.9% AB; 38.1% CD); winter (28.6% AB; 81% CD), and spring (23% AB; 49.3% CD). The incidence of SOM in the winter according to tympanometry was 18.4% (group AB) and 72.9% (group CD). Among children with a normal tympanogram in the fall, 44.7% presented a type B tympanogram (presence of middle ear effusion) in the winter. Only 17.6% still presented a type B tympanogram in the spring. From the ears with type B tympanogram in the fall, 80% had the same result in the winter, and 60.9%, in the spring. A sharp seasonal SOM peak was observed in the CD group in the winter. CONCLUSION Children in the lower socioeconomic group have a peak incidence of serous otitis media (OM) in the winter. Presence of type B tympanogram in the fall and belonging to socioeconomic group CD are indicators of poor prognosis in terms of the spontaneous resolution of SOM.

Comparação morfométrica da orelha interna entre ovinos e humanos através da tomografia computadorizada

INTRODUCTION Studies about the use of sheep in surgical training and experimental otologic surgery are rare. This study intends to contribute to the knowledge on this field. AIM To study sheep inner ear structures using computerized tomography and serial cross-sections to collect more accurate morphometric data to compare sheep and human ears. MATERIAL AND METHODS This descriptive study compared the inner structures of sheep and human ears. Measurements were made using computerized tomography, and they were stored in a DICOM compact disc for later analysis and manipulation, with a program used for medical image analysis (Osíris 4.16). RESULTS Mean measures for sheep and human ears were found to be similar in this morphological study. Most structures (10 out of 15) maintained the 2/3 ratio of sheep to human ear. CONCLUSION The results of this morphometric study of sheep ear are an important contribution to the development of an animal model to be used for surgical training and experimental otologic surgeries.

Transcanal Cochleostomy in Cochlear Implantation: Experience with 50 Cases

The objective of this study was to develop and test an endolabyrinthic microsurgical procedure for treatment of vertigo, the utriculostomy. This involves the application of local heat for obtaining a fistula in the membranous labyrinth, so as to establish communication between the endolymphatic and perilymphatic spaces at the utricle level. Before the procedure, an experimental model using quail eggs was built for pre-evaluation, and macroscopic and histological studies were performed in the temporal bones of three healthy sheep. Following this, the utriculostomy was performed through the oval window in 12 sheep. A microthermocautery was conceived by the first author and developed at Hospital de Clinicas de Porto Alegre. This equipment allows for control of temperature and duration of exposure to heat. Three months after the surgery, the animals were killed. A histological study of the temporal bones was performed to assess whether communication had been created between the endolymphatic and perilymphatic spaces, or whether a neomembrane had developed in the cauterized region. Histological sections of the vestibule of eight animals (three normal, five surgical) were analysed. All non-surgical cases presented a normal utricle wall. Three surgical cases (60%) presented a neomembrane. The absence of identifiable perforations in the utricle wall and the presence of neomembrane areas in 60% of the operated bones suggest that utriculostomy is a promising procedure for the treatment of Menieres disease.

Prevalence of the 35delG mutation in deaf South Brazilian infants submitted to cochlear implantation.

INTRODUCAO: trabalhos sobre o uso de ovelhas em cirurgias experimentais e treinamento em cirurgia otologica sao raros. Este estudo pretende contribuir para ampliar o conhecimento nessa area. OBJETIVO: Estudar a orelha interna da ovelha por meio de tomografia computadorizada e cortes sucessivos com o intuito de apresentar dados morfometricos mais precisos relacionados a comparacao entre a orelha de ovelhas e a de humanos. MATERIAL E METODO: Foi realizado um estudo descritivo sem seguimento no qual foram comparadas as estruturas da orelha interna da ovelha com as dos humanos. As medidas foram obtidas atraves de tomografias computadorizadas e avaliadas por meio de um programa de analise de imagens medicas (Osiris 4.16). RESULTADOS: O estudo morfologico da orelha da ovelha, em media, e da orelha humana, em media, revelaram grande similaridade de anatomia. A maior parte das estruturas (10 de 15) preservou a relacao proposta de 2/3 da dimensao humana em relacao a dimensao ovina. CONCLUSAO: Os achados contribuem para uso da orelha da ovelha como modelo em cirurgia experimental e treinamento em cirurgia otologica.

Distortion product otoacoustic emissions in sheep before and after hyperinsulinemia induction

Abstract The traditional access route for cochlear implantation was initially proposed by William House in 1961. Alternatives to this surgical approach have been suggested by many authors. The combined approach technique (CAT) is a variation of the traditional mastoidectomy-posterior tympanotomy method, which uses a transcanal approach to cochleostomy combined with a small mastoidectomy and an equally small posterior tympanotomy for the insertion of electrodes. This paper presents a detailed description of this alternative procedure, reporting our experience with 50 cases, and adds our contribution regarding possible advantages and implications of using a transcanal cochleostomy. The subjects had profound and severe bilateral hearing loss and had not benefited from external hearing aids. They underwent cochlear implantation at Hospital de Clinicas de Porto Alegre from May 2003. The median follow-up was 29 months. All cases were successfully implanted using CAT. No major complications, such as facial paralysis or paresis, meningitis, cholesteatoma, or cerebrospinal fluid leaks, were observed in any patient. The CAT is a safe and efficient variation of cochlear implantation surgery, which is especially appropriate if cochlear calcification or malformations are present, or whenever cochleostomy has to be performed anteriorly, and when the position of the facial nerve prevents an adequate posterior tympanotomy.

Cocleostomia transcanal: resultados em longo prazo de um estudo de coorte

OBJECTIVE Determine the prevalence of 35delG mutation in GJB2 gene in patients with prelingual deafness of no defined etiology whose underwent cochlear implant in the Otolaryngology Department at the Hospital de Clínicas de Porto Alegre and compare the speech recognition index using an open-set of sentences according to the presence or absence of the 35delG mutation. METHODS Cross-sectional study nested in a cohort. Were analyzed 37 patients with indeterminate etiology for deafness that underwent to cochlear implant. DNA was extracted and the mutations were studied using Polymerase Chain Reaction followed by gene sequencing. RESULTS The prevalence of 35delG mutation was 11%. The speech recognition index was 72% in the group with 35delG mutation, and 30% in the group without this mutation (p>0.05). CONCLUSIONS Prevalence of 35delG mutation in this study confirmed findings in the Brazilian literature. There was a clinically significant difference in hearing performance in patients with 35delG. Absence of statistical significance in this result might be attributed to the small number of patients with 35delG in our sample.

Histology of sheep temporal bone

UNLABELLED Transient evoked otoacoustic emissions and distortion product otoacoustic emissions have gained significant importance in the identification of cochlear alterations. AIM To record distortion product thresholds through the monitoring of otoacoustic emissions in normal conditions and in the presence of electrophysiologic changes in cochlear outer hair cells in sheep after hyperinsulinemia induction. MATERIAL AND METHODS Experimental study, with seven sheep in the control group and seven in the study group. Insulin and glucose concentrations were measured simultaneously for the recording of distortion product otoacoustic emission every 10 minutes, all the way to 90 minutes. The control group received saline solution, and the study group received a bolus injection of 0.1 U/kg of regular human insulin. RESULTS There was a significant reduction in distortion product thresholds in the study group when compared to the control group at frequencies greater than 1,500 Hz and after 60 minutes (P < 0.001). CONCLUSION This study established distortion product otoacoustic emission thresholds in sheep with constant reproducibility, demonstrating that the method is adequate for use in audiology and otology investigations. Results also fully confirm that acute hyperinsulinemia may cause important changes in these thresholds.