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Chirurgie de l'exophtalmie dysthyroïdienne : planning et assistance au geste

Vincent Luboz 1
1 TIMC-GMCAO - Gestes Medico-chirurgicaux Assistés par Ordinateur
TIMC - Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525
Abstract : This thesis proposes a study of the intra-orbital soft tissue behaviour in the framework of the exophthalmia treatment, characterised by a protrusion of the ocular globe. The surgical part of this treatment consists in an orbital decompression via an osteotomy of the bone structures to reduce the globe protrusion. This study aims to predict relationships between the decompressed tissue volume, the osteotomy area and the resulting ocular backward displacement in order to help during the surgical planning phase. Two models have been developed. The first one is a simple analytical model of the orbit, assuming that the bony walls and the eye ball are a cone and a sphere. It allows to give a satisfying estimation of the decompressed tissue volume in function of the given backward displacement. The second one is a biomechanical model of the intra-orbital soft tissues and of their interactions with the bony walls and the eye ball. It is a Finite Element mesh using a poroelastic material and taking into account the patient orbit morphology, the mechanical properties of the soft tissues. It allows to quantify the ocular backward displacement and the decompressed tissue volume in function of the load (or the displacement) imposed by the surgeon and the osteotomy (surface and location). Its results are relatively interesting and give an evaluation of the behaviour of the intra-orbital soft tissues. The automatic method to generate Finite Element meshes, developed in this thesis, has permit to do various osteotomy simulations and to conclude that the patient orbit morphology has an impact on the backward displacement and on the decompressed volume and that the influence of the osteotomy surface is moderated. A rheologic analysis of the orbital soft tissues has been performed. These in vitro tests have allowed to set the bases for future measurements. In vivo tests, done with an ad hoc sensor, have determined the stiffness of the soft tissues. Though the models presented here are not yet usable in a surgical planning framework, they give satisfying results and a good estimation of the phenomenon observed during an orbital decompression.
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https://tel.archives-ouvertes.fr/tel-00005178
Contributor : Vincent Luboz <>
Submitted on : Monday, March 1, 2004 - 11:07:35 PM
Last modification on : Tuesday, November 24, 2020 - 4:18:04 PM

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Vincent Luboz. Chirurgie de l'exophtalmie dysthyroïdienne : planning et assistance au geste. Sciences du Vivant [q-bio]. Institut National Polytechnique de Grenoble - INPG, 2003. Français. ⟨tel-00005178⟩

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