https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 15 Jun 2026 14:10:14 GMT 2026-06-15T14:10:14Z http://hdl.handle.net/10985/19921 A Cellular Potts energy-based approach to analyse the influence of the surface topography on single cell motility THENARD, Thomas; CATAPANO, Anita; MESNARD, Michel; ALLENA, Rachele cellular scale level, the cell behaviour, especially its migration, is affected by the specificities of the surface of the substrate, such as the stiffness of the surface and its roughness topography. The latter has been shown to have a great impact on various cell mechanisms, such as the cell adhesion, migration, or proliferation. In fact, the mere presence of micro roughness leads to an improvement of those mechanisms, with a better integration of the implants. However, the phenomena behind those improvements are still not clear. In this paper, we propose a three-dimensional (3D) model of a single cell migration using a Cellular Potts (CP) model to study the influence of the surface topography on cell motility. To do so, various configurations were tested, such as: (i) a substrate with a random roughness, (ii) a substrate with a rectangular groove pattern (parallel and perpendicular to the direction of motion), (ii) a substrate with a sinusoidal groove pattern. To evaluate the influence of the surface topography on cell motility, for each configuration, the cell speed and shape as well as the contact surface between the cell and the substrate have been quantified. Our numerical results demonstrate that, in agreement with the experimental observations of the literature, the substrate topography has an influence on the cell efficiency (i.e. cell speed), orientation and shape. Besides, we also show that the increase of the contact surface alone in presence of roughness is not enough to explain the improvement of cell migration on the various rough surfaces. Finally, we highlight the importance of the roughness dimension on cell motility. This could be a critical aspect to consider for further analyses and applications, such as surface treatments for medical applications. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/19921 2021-01-01T00:00:00Z THENARD, Thomas CATAPANO, Anita MESNARD, Michel ALLENA, Rachele cellular scale level, the cell behaviour, especially its migration, is affected by the specificities of the surface of the substrate, such as the stiffness of the surface and its roughness topography. The latter has been shown to have a great impact on various cell mechanisms, such as the cell adhesion, migration, or proliferation. In fact, the mere presence of micro roughness leads to an improvement of those mechanisms, with a better integration of the implants. However, the phenomena behind those improvements are still not clear. In this paper, we propose a three-dimensional (3D) model of a single cell migration using a Cellular Potts (CP) model to study the influence of the surface topography on cell motility. To do so, various configurations were tested, such as: (i) a substrate with a random roughness, (ii) a substrate with a rectangular groove pattern (parallel and perpendicular to the direction of motion), (ii) a substrate with a sinusoidal groove pattern. To evaluate the influence of the surface topography on cell motility, for each configuration, the cell speed and shape as well as the contact surface between the cell and the substrate have been quantified. Our numerical results demonstrate that, in agreement with the experimental observations of the literature, the substrate topography has an influence on the cell efficiency (i.e. cell speed), orientation and shape. Besides, we also show that the increase of the contact surface alone in presence of roughness is not enough to explain the improvement of cell migration on the various rough surfaces. Finally, we highlight the importance of the roughness dimension on cell motility. This could be a critical aspect to consider for further analyses and applications, such as surface treatments for medical applications. http://hdl.handle.net/10985/19920 Topography and wettability characterization of surfaces manufactured by SLM and treated by chemical etching THENARD, Thomas; ALLENA, Rachele; MESNARD, Michel; MOHAMED, El May; SAINTIER, Nicolas; CATAPANO, Anita Selective Laser Melting process represents an interesting opportunity in the biomedical field to fabricate customized implants. However, the surface roughness of components obtained through additive manufacturing is a major limitation and affects the surface wettability. In the present work, chemical etching is adopted to deal with such an issue. To do so, the effects of chemical etching parameters (such as immersion time and composition of the solution) on the surface roughness, weight loss and wettability is analyzed. Different samples (obtained through different printing orientations) are considered. The tests show that the roughness and the wetting of the surfaces are improved thanks to chemical etching. As a major result, the most influencing parameters on surface wetting are two: the roughness and the material properties (which vary with samples depth). Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/19920 2020-01-01T00:00:00Z THENARD, Thomas ALLENA, Rachele MESNARD, Michel MOHAMED, El May SAINTIER, Nicolas CATAPANO, Anita Selective Laser Melting process represents an interesting opportunity in the biomedical field to fabricate customized implants. However, the surface roughness of components obtained through additive manufacturing is a major limitation and affects the surface wettability. In the present work, chemical etching is adopted to deal with such an issue. To do so, the effects of chemical etching parameters (such as immersion time and composition of the solution) on the surface roughness, weight loss and wettability is analyzed. Different samples (obtained through different printing orientations) are considered. The tests show that the roughness and the wetting of the surfaces are improved thanks to chemical etching. As a major result, the most influencing parameters on surface wetting are two: the roughness and the material properties (which vary with samples depth). http://hdl.handle.net/10985/12115 Optimization of a dynamic intervertebral lumbar implant LEDOUX, Yann; MESNARD, Michel; PEÑALOZA SANDOVAL, Jorge Andrés; PERRY, Nicolas For the surgical treatment of lumbar pathologies, there are essentially two medical devices that are implanted. Spinal fusion by means of a screwed plate generates a loss of intervertebral mobility, whereas a spinal dynamic implant (SPD) allows relative displacements and thus preserves the adjacent segments and discs. The main goal of this study is to structure the design and to optimize such SPDs. An analytic model based on geometrical and mechanical relations is set up. The characteristics derive from data taken from bibliographical studies. Optimization of the implant characteristics is carried out (materials used, component stiffness, orientation associated with bone tissue degeneration, etc.). To do this, the optimization problem is structured to combine design variables, the mechanical behavior of the medical device (MD) and functional requirements into a single design model allowing the optimization of the MD behavior through a global index. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/12115 2016-01-01T00:00:00Z LEDOUX, Yann MESNARD, Michel PEÑALOZA SANDOVAL, Jorge Andrés PERRY, Nicolas For the surgical treatment of lumbar pathologies, there are essentially two medical devices that are implanted. Spinal fusion by means of a screwed plate generates a loss of intervertebral mobility, whereas a spinal dynamic implant (SPD) allows relative displacements and thus preserves the adjacent segments and discs. The main goal of this study is to structure the design and to optimize such SPDs. An analytic model based on geometrical and mechanical relations is set up. The characteristics derive from data taken from bibliographical studies. Optimization of the implant characteristics is carried out (materials used, component stiffness, orientation associated with bone tissue degeneration, etc.). To do this, the optimization problem is structured to combine design variables, the mechanical behavior of the medical device (MD) and functional requirements into a single design model allowing the optimization of the MD behavior through a global index. http://hdl.handle.net/10985/8508 Managing the variability of biomechanical characteristics before the preliminary design stage of a medical device MESNARD, Michel; RAMOS, Antonio; PERRY, Nicolas The very high level of requirements for certification procedures often limit research and development departments to innovate using increments and iterations during the design process for medical devices (MD). Instead of this semi-empirical approach, a structured procedure, a breakthrough innovation should be used when designing an articular MD (prosthesis, implant). The search for concepts can be based on functional analysis and producing behavioural models of the joint in its natural state and/or equipped with the prosthesis. This paper shows how anatomical variables can be managed and integrated using a modular design approach. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8508 2014-01-01T00:00:00Z MESNARD, Michel RAMOS, Antonio PERRY, Nicolas The very high level of requirements for certification procedures often limit research and development departments to innovate using increments and iterations during the design process for medical devices (MD). Instead of this semi-empirical approach, a structured procedure, a breakthrough innovation should be used when designing an articular MD (prosthesis, implant). The search for concepts can be based on functional analysis and producing behavioural models of the joint in its natural state and/or equipped with the prosthesis. This paper shows how anatomical variables can be managed and integrated using a modular design approach. http://hdl.handle.net/10985/25062 Study of mechanical effects of lumbar disc arthroplasty on facet joints at the index level/adjacent levels by using a validated finite element analysis ZOT, François; BEN-BRAHIM, Estelle; SEVERYNS, Mathieu; LEDOUX, Yann; MESNARD, Michel; CAILLÉ, Laëtitia; SWENNEN, Cécile; TEYSSÉDOU, Simon; MOUFID, Abdollah-Yassine; GERMANEAU, Arnaud; VENDEUVRE, Tanguy Introduction: Lumbar disc arthroplasty is a surgical procedure designed to treat degenerative disc disease by replacing the affected disc with a mobile prosthesis. Several types of implants fall under the term total disc replacement, such as ball-and-socket, mobile core or elastic prostheses. Some studies have shown that facet arthritis can develop after arthroplasty, without much precision on the mechanical impact of the different implant technologies on the facet joints. This study aims to create validated patient-specific finite element models of the intact and post-arthroplasty lumbar spine in order to compare the mechanical response of ball-and-socket and elastic prostheses.Methods: Intact models were developed from CT-scans of human lumbar spine specimens (L4-S1), and arthroplasty models were obtained by replacing the L4-L5 disc with total disc replacement implants. Pure moments were applied to reproduce physiological loadings of flexion/extension, lateral bending and axial rotation.Results: Models with ball-and-socket prosthesis showed increased values in both range of motion and pressure at the index level and lower values at the adjacent level. The mechanical behaviour of the elastic prosthesis and intact models were comparable. The dissipated friction energy in the facet joints followed a similar trend.Conclusion: Although both implants responded to the total disc replacement designation, the mechanical effects in terms of range of motion and facet joint loads varied significantly not only between prostheses but also between specimens. This confirms the interest that patient-specific surgical planning using finite element analysis could have in helping surgeons to choose the appropriate implant for each patient. Tue, 21 Nov 2023 00:00:00 GMT http://hdl.handle.net/10985/25062 2023-11-21T00:00:00Z ZOT, François BEN-BRAHIM, Estelle SEVERYNS, Mathieu LEDOUX, Yann MESNARD, Michel CAILLÉ, Laëtitia SWENNEN, Cécile TEYSSÉDOU, Simon MOUFID, Abdollah-Yassine GERMANEAU, Arnaud VENDEUVRE, Tanguy Introduction: Lumbar disc arthroplasty is a surgical procedure designed to treat degenerative disc disease by replacing the affected disc with a mobile prosthesis. Several types of implants fall under the term total disc replacement, such as ball-and-socket, mobile core or elastic prostheses. Some studies have shown that facet arthritis can develop after arthroplasty, without much precision on the mechanical impact of the different implant technologies on the facet joints. This study aims to create validated patient-specific finite element models of the intact and post-arthroplasty lumbar spine in order to compare the mechanical response of ball-and-socket and elastic prostheses.Methods: Intact models were developed from CT-scans of human lumbar spine specimens (L4-S1), and arthroplasty models were obtained by replacing the L4-L5 disc with total disc replacement implants. Pure moments were applied to reproduce physiological loadings of flexion/extension, lateral bending and axial rotation.Results: Models with ball-and-socket prosthesis showed increased values in both range of motion and pressure at the index level and lower values at the adjacent level. The mechanical behaviour of the elastic prosthesis and intact models were comparable. The dissipated friction energy in the facet joints followed a similar trend.Conclusion: Although both implants responded to the total disc replacement designation, the mechanical effects in terms of range of motion and facet joint loads varied significantly not only between prostheses but also between specimens. This confirms the interest that patient-specific surgical planning using finite element analysis could have in helping surgeons to choose the appropriate implant for each patient.