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Search Results: 1 - 10 of 1037 matches for " Franck Boutault "
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Intra-operative quantification of the surgical gesture in orbital surgery: Application to the proptosis reduction
Vincent Luboz,Pascal Swider,Dominique Ambard,Franck Boutault,Yohan Payan
Physics , 2007,
Abstract: Proptosis is characterized by a protrusion of the eyeball due to an increase of the orbital tissue volume. To recover a normal eyeball positioning, the most frequent surgical technique (BROD technique) consists in the osteotomy of orbital walls combined with a loading on the eyeball to initiate tissue decompression. This paper proposed an experimental method to quantify the intra-operative clinical gesture in proptosis reduction, and the pilot study concerned one clinical case. The eyeball's backward displacement was measured by an optical 3D localizer and the load applied by the surgeon was simultaneously measured by a custom-made force gauge. Quasi-static stiffness of the intra-orbital content was evaluated. The average values for the whole experiment was 16 N (SD: 3 N) for the force exerted by the surgeon and 9 mm (SD: 4 mm) for the eyeball backward displacement. The averaged quasi-static stiffness of the orbital content was evaluated to 2.4 N/mm (SD: 1.2) and showed a global decrease of 45% post-operatively.
Simulation of the Exophthalmia Reduction using a Finite Element Model of the Orbital Soft Tissues
Vincent Luboz,Annaig Pedrono,Franck Boutault,Pascal Swider,Yohan Payan
Physics , 2006,
Abstract: This paper proposes a computer-assisted system for the surgical treatment of exophthalmia. This treatment is classically characterized by a de-compression of the orbit, by the mean of an orbital walls osteotomy. The plan-ning of this osteotomy consists in defining the size and the location of the de-compression hole. A biomechanical model of the orbital soft tissues and its in-teractions with the walls are provided here, in order to help surgeons in the definition of the osteotomy planning. The model is defined by a generic Finite Element poro-elastic mesh of the orbit. This generic model is automatically adapted to the morphologies of four patients, extracted from TDM exams. Four different FE models are then generated and used to simulate osteotomies in the maxillary or ethmoid sinuses regions. Heterogeneous results are observed, with different backwards movements of the ocular globe according to the size and/or the location of the hole.
Comparison of linear and non-linear soft tissue models with post-operative CT scan in maxillofacial surgery
Matthieu Chabanas,Yohan Payan,Christophe Marecaux,Pascal Swider,Franck Boutault
Physics , 2006,
Abstract: A Finite Element model of the face soft tissue is proposed to simulate the morphological outcomes of maxillofacial surgery. Three modelling options are implemented: a linear elastic model with small and large deformation hypothesis, and an hyperelastic Mooney-Rivlin model. An evaluation procedure based on a qualitative and quantitative comparison of the simulations with a post-operative CT scan is detailed. It is then applied to one clinical case to evaluate the differences between the three models, and with the actual patient morphology. First results shows in particular that for a "simple" clinical procedure where stress is less than 20%, a linear model seams sufficient for a correct modelling.
Computer assisted planning and orbital surgery: patient-related prediction of osteotomy size in proptosis reduction
Vincent Luboz,Dominique Ambard,Pascal Swider,Franck Boutault,Yohan Payan
Physics , 2006,
Abstract: BACKGROUND: Proptosis is characterized by a protrusion of the eyeball due to an increase of the orbital tissue volume. To recover a normal eyeball positioning, the most frequent surgical technique consists in the osteotomy of orbital walls combined with the manual loading on the eyeball. Only a rough clinical rule is currently available for the surgeons but it is useless for this technique. The first biomechanical model dealing with proptosis reduction, validated in one patient, has been previously proposed by the authors. METHODS: This paper proposes a rule improving the pre-operative planning of the osteotomy size in proptosis reduction. Patient-related poroelastic FE models combined with sensitivity studies were used to propose two clinical rules to improve the pre-operative planning of proptosis reduction. This poroelastic model was run on 12 patients. Sensitivity studies permitted to establish relationships between the osteotoemy size, the patient-related orbital volume, the decompressed tissue volume and the eyeball backward displacement. FINDINGS: The eyeball displacement and the osteotomy size were non-linearly related: an exponential rule has been proposed. The patient-related orbital volume showed a significant influence: a bi-quadratic analytical equation liking the osteotomy size, the orbital volume and the targeted eyeball protrusion has been established. INTERPRETATION: Two process rules derived from patient-related biomechanical FE models have been proposed for the proptosis reduction planning. The implementation of the process rules into a clinical setting is easy since only a sagittal radiography is required. The osteotomy size can be monitored using optical guided instruments.
Models for Planning and Simulation in Computer Assisted Orthognatic Surgery
Matthieu Chabanas,Christophe Marecaux,Yohan Payan,Franck Boutault
Physics , 2006,
Abstract: Two aspects required to establish a planning in orthognatic surgery are addressed in this paper. First, a 3D cephalometric analysis, which is clini-cally essential for the therapeutic decision. Then, an original method to build a biomechanical model of patient face soft tissue, which provides evaluation of the aesthetic outcomes of an intervention. Both points are developed within a clinical application context for computer aided maxillofacial surgery.
Computer aided planning and navigation for orbito-zygomatic reconstruction
Christophe Marecaux,Matthieu Chabanas,Yohan Payan,Franck Boutault
Physics , 2007,
Abstract: This paper suggests a full protocol of Computer Aided Surgery as previously recommended in literature addressing the challenging task of primary or secondary reconstruction of orbito-zygomatic dislocation. First, on a specifically developed planning software, the best zygoma reduction and orbital boundaries reconstruction to achieve skeletal symmetry are determined. This treatment plan is then transferred to the 3D Navigation Systems within the operating room. After patient's anatomy registration to his preoperative CT scan data, the navigation system allows zygomatic guiding to its planned reduced location and bone orbital volume restoration control. The feasibility of this technique was checked in 3 patients with major orbito-zygomatic deformities. Preliminary clinical results are presented.
Evaluating soft tissue simulation in maxillofacial surgery using pre and post-operative CT scan
Matthieu Chabanas,Christophe Marecaux,Franz Chouly,Franck Boutault,Yohan Payan
Physics , 2006,
Abstract: One of the most important issue in soft tissue modeling is to assess the quality of the simulations. A validation protocol is presented based on two CT scans of the patient acquired before and after cranio-maxillofacial surgery. The actual bones repositioning realized during the intervention are accurately measured and reproduced. A evaluation of the soft tissue deformation is then computed using a finite element model of the face. The simulations are therefore compared, qualitatively and quantitatively, with the actual outcome of the surgery. This protocol enable to rigorously evaluate different modeling methods, and to assess the clinical relevance of soft tissue simulation in maxillofacial surgery.
A 3D Finite Element evaluation of the exophthalmia reduction
Vincent Luboz,Annaig Pedrono,Franck Boutault,Pascal Swider,Yohan Payan
Physics , 2006,
Abstract: This paper presents a first evaluation of the feasibility of Finite Element modelling of the orbital decompression, in the context of exophthalmia. First simulations are carried out with data extracted from a patient TDM exam. Results seem to qualitatively validate the feasibility of the simulations, with a Finite Element analysis that converges and provides a backward movement of the ocular globe associated with displacements of the fat tissues through the sinuses. This FE model can help a surgeon for the planning of the exophthalmia reduction, and especially for the position and the size of the decompression hole. To get an estimation of the fat tissues volume affected by the surgery, an analytical model seems to provide quicker results for an equivalent efficiency.
Computer aided planning for orthognatic surgery
Matthieu Chabanas,Christophe Marecaux,Yohan Payan,Franck Boutault
Physics , 2006,
Abstract: A computer aided maxillofacial sequence is presented, applied to orthognatic surgery. It consists of 5 main stages: data acquisition and integration, surgical planning, surgical simulation, and per operative assistance. The planning and simulation steps are then addressed in a way that is clinically relevant. First concepts toward a 3D cephalometry are presented for a morphological analysis, surgical planning, and bone and soft tissue simulation. The aesthetic surgical outcomes of bone repositioning are studied with a biomechanical Finite Element soft tissue model.
A stiffness sensor to help in the diagnosis and the surgery of orbital pathologies
Vincent Luboz,Dominique Ambard,Franck Boutault,Pascal Swider,Yohan Payan
Physics , 2006,
Abstract: Proptosis is characterized by a protrusion of the eyeball due to an increase of the orbital tissue volume. To recover a normal eyeball positioning, the most frequent surgical technique (BROD technique) consists in the osteotomy of orbital walls combined with a loading on the eyeball to initiate tissue decompression. In this paper, a stiffness sensor device is proposed to (1) provide to the surgeon pre, intra and post-operative data concerning the stiffness of the intra-orbital soft tissues, and (2) provide constitutive parameters to the Finite Element model of the intra-orbital tissues already developed by the authors and used to predict consequences orbital surgery.
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