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Title: A safe landmark for labyrinthine preservation in acoustic neurinoma surgery
Authors: Silveira, Roberto Leal da [UNIFESP]
Ferraz, Fernando Antonio Patriani [UNIFESP]
Gusmao, Sebastiao Nataniel Silva [UNIFESP]
Cabral, G.
Sterkers, J. M.
Charachon, R.
Sterkers, O.
ODonoghue, G.
Fenton, J.
Universidade Federal de São Paulo (UNIFESP)
Issue Date: 1-Jan-1996
Publisher: Kugler Publications Bv
Citation: Acoustic Neuroma And Skull Base Surgery. Amstelveen: Kugler Publications Bv, p. 277-287, 1996.
Abstract: Considering the importance of keeping the labyrinth intact during the opening of the posterior meatal wall in acoustic neurinoma surgery, in an attempt to preserve the remaining hearing in certain cases, the external aperture of the vestibular aqueduct (EAVA) was evaluated as a landmark to help in the preservation of the labyrinth by the suboccipital retrosigmoid transmeatal approach. Dry and wet temporal bones, patients harboring acoustic neurinomas and high-resolution computerized tomography scans were evaluated. The correlations between the EAVA, porus and transverse crest were observed before and after opening the posterior meatal wall. Measurements were taken between these structures. Cadaveric head dissections were carried out to expose the EAVA together with the exit of the endolymphatic sac. The posterior meatal wall was drilled away, but not up to the EAVA. Finally, the vestibular aqueduct, common crus and posterior semicircular canal were opened to ensure that they had not been injured previously, and to make sure that there was still bone between the lateral meatal end and the labyrinth. The same landmark has been used in the last surgical cases in an attempt to preserve the bone labyrinth. There was consistent correlation between the lateral meatal end, EAVA and labyrinth. The distance from the porus to the EAVA was never shorter than the distance from the porus to the transverse crest. The EAVA was usually located laterally to the perpendicular projection of the meatus fundus in the posterior surface of the petrous bone, and when this landmark was in direct line of sight, it offered an appropriate angle for avoiding the postero-medial part of the labyrinth. If the posterior meatal wall was not opened up to the EAVA, the labyrinth could be preserved. The results of the surgical cases have shown that, in all patients, the labyrinth was preserved, and the tumors completely removed. The present study suggests that the EAVA can be used as a safe landmark to help in labyrinthine preservation, while drilling the posterior meatal wall by the suboccipital retrosigmoid approach.
Other Identifiers: (Livro) Não encontrado
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