Surgical treatment of vertigo by utriculostomy: an experimental study in sheep.

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 Meniere's disease.

Irradiacao endolinfatica. Metodo util para imunessupressao em transplante renal. / Endolymphatic irradiation. A useful method for immunosuppression in renal transplantation

Foi analisado tardiamente a evolucao clinica e o destino do enxerto renal em 24 pacientes (grupo I) que receberam injecao endolinfatica do 131I como medida imunessupressora pre-transplante. O grupo-controle (grupo II) constituiu-se de 24 pacientes nao irradiados e comparaveis ao grupo I quanto a idade, sexo, diagnostico de doenca primaria, tipo de doador e terapia imunessupressora. Diferenca significativa entre os dois grupos foi encontrada com relacao a incidencia e reversibilidade das crises de rejeicao nos primeiros 60 dias pos-transplantes; perda de rim em rejeicao e dose de manutencao de azatioprina. Os autores concluem que o metodo, alem de inocuo, tem acao imunessupressora prolongada, podendo ser indicado para receptores de rim de cadaver, sobretudo os casos que apresentam a cross-match positivo contra antigenos HLA para painel

Mudancas na composicao ionica da perilinfa e da endolinfa como consequencia de microembolias em capilares da coclea: um estudo experimental. / Changes in the ionic composition of the perilymph and endolymph due to microembolism in the cochlear capillaries: an experimental study

Suspensoes de microesferas de poliestireno, copolimero foram injetadas atraves do coracao esquerdo em chinchillas normais.Em seguida as areas capilares da coclea foram estudadas em preparacoes de superficie coradas pelo azul da Prussia e as microesferas foram demonstradas no interior de capilares pertencentes a todas as areas capilares da coclea com predominancia da estria vascularis. Em prosseguimento as concentracoes de sodio e potassio na endolinfa e perilinfa foram estudadas depois de varios intervalos de tempo a contar da injecao de microembolos. Os resultados sao apresentados e discutidos nesta comunicacao

Endolymph flow-pressure patterns in models of semicircular canals. Effects of angular accelerations in one or two spatial planes.

The effects of angular accelerations in one or two spatial planes over the pressure exerted on the cupule of the semicircular canals, was studied using hydraulic models of the canals. The models were accelerated using a torsion pendulum and the resulting flow was monitored. The relative position of the model modifies the direction and magnitude of the flow in each canal and in the equivalent of the utricle where the canals join each other. When simultaneous accelerations in two spatial planes were used, a coriolic effect was observed, which could be significant to explain some vestibular symptoms that occur under similar conditions. From the information obtained with the models, the excitation-inhibition patterns in each of the six semicircular canals can be predicted for accelerations in any given spatial plane or combination of planes.