Christophe Degueurce - Academia.edu (original) (raw)

Papers by Christophe Degueurce

General description of “El Naceri” (1333 AD) translated by the author into French from the Arabic... more General description of “El Naceri” (1333 AD) translated by the author into French from the Arabic text of Abou Bakr. Quotes of the most significant parts of the ten chapters of the book, highlighting their scientific and poetic value.

MAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

HAL (Le Centre pour la Communication Scientifique Directe), 2007

HAL (Le Centre pour la Communication Scientifique Directe), 2004

American Journal of Veterinary Research

To evaluate asymmetry in placement of bilateral skin markers on horses and to determine effect of... more To evaluate asymmetry in placement of bilateral skin markers on horses and to determine effect of asymmetric skin marker placement on kinematic variables for trotting horses. 10 horses for evaluation of asymmetry in marker placement; 1 horse for evaluation of effects on kinematic variables. Asymmetry in marker placement was assessed by attaching markers to horses and comparing radiographs of left and right limbs. An experimental model was developed to determine effects on kinematic variables; accuracy of the model was validated experimentally. Using kinematic data from a clinically normal trotting horse as reference data, effects of asymmetric marker placement on vertical displacement-time and joint angle-time diagrams were determined by use of the model. Asymmetry of placement was < 1 cm for markers on the distal portions of the limbs and < 2 cm for markers on the proximal portions. Asymmetric marker placement did not alter general shapes of the vertical displacement-time and...

Veterinary research

This study was conducted to evaluate a method for quantifying the flexion-extension movements of ... more This study was conducted to evaluate a method for quantifying the flexion-extension movements of the back of horses trotting on a track in the conditions of the clinical lameness examination. Using a 3-D kinematic analysis system, the successive positions of four markers placed at regular intervals between the withers and the tuber sacrale were recorded. To isolate the flexion-extension movements of the back, the positions of these four markers were recomputed in a trunk-related co-ordinate system of the horse. Then, for each frame, the equation of the third-order polynomial that best fitted the position of the four markers was determined. Using these equations, it was then possible to interpolate the vertical displacement of any point situated between the withers and the tuber sacrale. The accuracy of this method was evaluated using three additional markers placed between the four previous ones. The vertical displacements of these three markers were recorded and compared to the int...

Medical & Biological Engineering & Computing, 1996

Journal of Biomechanics, 1994

ITBM-RBM, 2003

Le système d'analyse cinématique ZEBRIS CMS-HS calcule, en temps réel, les coordonnées tridimensi... more Le système d'analyse cinématique ZEBRIS CMS-HS calcule, en temps réel, les coordonnées tridimensionnelles de marqueurs cinématiques en utilisant le principe de la triangulation ultrasonore. Cependant, la propagation des ondes ultrasonores peut être altérée par des facteurs extérieurs tels que les réflexions du signal, le vent, les variations de température. Pour chacune de ces conditions, les coordonnées 3D d'un système de six marqueurs immobiles ont été mesurées, permettant le calcul d'angles et de distances théoriquement invariables. La précision du système a été évaluée par la dispersion des valeurs autours de la moyenne calculée pour chaque série de mesures. Dans les conditions standard du laboratoire, la précision des mesures était de ± 0,14 mm sur les distances et ± 0,16°sur les angles. Des phénomènes de réflexion des ultrasons peuvent provoquer l'apparition d'erreurs systématiques de l'ordre de 0,2°et altèrent la répétabilité des mesures. Le vent diminue la précision des mesures proportionnellement à sa vitesse. La température ambiante influe sur l'exactitude des mesures. En conséquence, celle-ci doit être correctement paramétrée. La précision des mesures diminue en éloignant ou en décalant les émetteurs par rapport aux microphones lorsque la distance excède 1,5 m. Cette étude permet d'évaluer les causes d'imprécision de mesure pour le système et de définir les limites d'utilisation de celui-ci.

Equine Veterinary Journal, 1997

ABSTRACT This study of the locomotion symmetry was undertaken to provide standard symmetry indice... more ABSTRACT This study of the locomotion symmetry was undertaken to provide standard symmetry indices of a group of sound horses at the trot. Using a 3D data collection system, the kinematics of the limb joints of 13 clinically nonlame horses were recorded while trotting in the standard conditions of the clinical lameness examination. A kinematic symmetry indice based on an inter-correlation method was defined and applied to the vertical displacement-time and joint angle-time diagrams of the left and right joints of the horses. For each horse, the mean symmetry indice of each joint was calculated using values from 5 trials. For each joint, these means were then averaged. To evaluate the repeatability of the locomotion symmetry, the intra- and inter-individual variabilities of the symmetry indices were studied. The levels of symmetry of the markers of the trunk were generally lower than those of the limbs. Moreover, during the 5 trials these levels of symmetry were strongly variable but their mean values were very similar from one horse to another. In our experimental conditions the trunk presented a higher degree of freedom than the limbs. This high intra-individual variability indicated also that several trials are necessary to quantify the locomotion symmetry of a trotting horse. In the same way, a lower level of symmetry of the hindlimbs, compared to the forelimbs, was proved by their lower values of symmetry indices. As opposed to the supporting role of the forelimbs, the propulsive role of the hindlimbs may explain this feature.

Equine Veterinary Journal, 2010

ABSTRACT

Equine Veterinary Journal, 2001

This study was undertaken to describe the symmetry of movements of fore- and hindlimbs in horses ... more This study was undertaken to describe the symmetry of movements of fore- and hindlimbs in horses suffering from various spontaneous lamenesses. Two groups of horses were studied: 13 clinically sound horses and 24 lame horses. Using a 3-dimensional (3-D) kinematic analysis system, movements of both sides of each horse were recorded simultaneously while trotting on a track. The differences in motion between left and right homologous joints of each horse were quantified using symmetry indices based on an intercorrelation method. Symmetry indices obtained for each lame horse were then compared with those of sound horses. This comparison showed that the most sensitive lameness indicators were the symmetry indices of the vertical displacement of the proximal markers of the limbs. Symmetry indices of each lame horse were also compared with those of the other lame horses, using correlation coefficients to determine whether or not various lamenesses generate similar alterations of the locomotion symmetry. Values of these coefficients allowed 2 types of lameness to be distinguished. In 21 lame horses, the largest alterations in the symmetry of vertical movements were observed for the proximal markers of the limbs, which may reflect the supporting component of these lamenesses. In contrast, the asymmetries in vertical movements were more pronounced for the distal markers in 3 horses (one stringhalt and 2 carpal injuries), which may reflect the swinging component of these lamenesses. This cross-correlation method can be implemented easily in a computer programme and may represent a first step in the development of an expert system.

Equine Veterinary Journal, 2001

Many clinical reports have previously documented the advantages of plates or external fixations b... more Many clinical reports have previously documented the advantages of plates or external fixations but surgeons prefer to use plate for better acceptance by the owner, less dressing and a decreased rate of infection. In order to address complications of carpal surgery, infections, arthritis and osteomyelitis, external fixation is warranted. Twelve canine forelimbs, free of abnormality, were tested under compression to evaluate the in vitro biomechanical behaviour of the normal carpus. This behaviour was compared with that of a stabilized carpus stabilised by panarthrodesis with either plates (8 hole 3.5 mm dynamic compression plate (DCP), or a type II external fixator. Deformation vs. load was recorded after compression with a testing machine in conjunction with a digital data acquisition system. Yield load, maximal load to failure and stiffness were then calculated. Variables were significantly greater for arthrodesis with external fixation and plates than for intact forelimbs. The stiffness and the MLF after stabilisation with plates or external fixators did not differ significantly. At MLF, fracture of the third metacarpus appeared with plates, whereas deformations of the pins and bars of the external fixators increased with load. Stabilisation with plate or external fixation allowed more load to failure than the intact carpus. The biomechanical behaviour of both methods of arthrodesis was identical during loading. However, after rupture, external fixation was more plastic. External fixation, which is less often used than plates for pancarpal arthrodesis, mainly due to the occurrence of sepsis, may be useful for arthrodesis of the carpus in big or active dogs.

Equine Veterinary Journal, 2010

Sacroiliac joint (SIJ) disease is associated with poor hindlimb action, lameness and poor perform... more Sacroiliac joint (SIJ) disease is associated with poor hindlimb action, lameness and poor performance in horses. However, little is known about the biomechanics of this low-motion joint. To determine in vitro the capacities of movement of the SIJ in the sagittal plane, and to test the effect of a sacrosciatic and sacrotuberal desmotomy on its stabilisation. Six anatomical specimens underwent cycles of flexion-extension of the lumbosacral joint (LSJ) before and after desmotomy. Kinematic triads were linked rigidly to the sacrum, spinous process of vertebra L5 and iliac wing. Angles were measured using a joint coordinate system based on anatomical frames. The LSJ underwent regular movements of flexion and extension (overall mean +/- s.d. range 23.4 +/- 1.6 degrees). The only recorded movement of the SIJ was a nutation during LSJ flexion (overall mean +/- s.d. 0.8 +/- 0.5 degrees). Desmotomy induced an increase of that nutation (overall mean +/- s.d. 1.7 +/- 0.2 degrees). Movements of the SIJ were small and coupled only with the flexion of the LSJ. The ligaments surrounding the SIJ have a strong effect on the stabilisation of this joint. Due to the limited amount of movement, its biomechanical study in vivo seems to be difficult. Further in vitro studies would be useful to determine the role of each ligament, to better understand the clinical consequences of the tears frequently observed during necropsy.

Archives of Physiology and Biochemistry, 1995

Archives of Physiology and Biochemistry, 1995

The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden.

P r é s e n t a t i o n d e l ' é d i t e u r Jusqu'au XIXe siècle la formation des médec... more P r é s e n t a t i o n d e l ' é d i t e u r Jusqu'au XIXe siècle la formation des médecins en anatomie comportait un incontournable : la dissection de corps humains ou animaux. Avec le risque toujours important de la piqure anatomique transmetteuse de germes et surtout la difficulté grandissante à se procurer des corps. Il existait bien des modèles anatomiques en cire mais lourds chers et peu pratiques ils étaient peu utilisés. C'est alors que le docteur Auzoux mit au point un procédé révolutionnaire par sa simplicité : la fabrication de corps en papier mâché. Grâce à d'habiles charnières on pouvait retirer peau muscles organes viscères. L'anatomie clastique était née. Auzoux proposa différents modèles ainsi que des détails. Puis il passa à des modèles animaliers puis végétaux gardant toujours en tête l'éducation des médecins ou des vétérinaires mais aussi des masses. L'entreprise Auzoux connut alors un succès commercial important et une diffusion inter...

General description of “El Naceri” (1333 AD) translated by the author into French from the Arabic... more General description of “El Naceri” (1333 AD) translated by the author into French from the Arabic text of Abou Bakr. Quotes of the most significant parts of the ten chapters of the book, highlighting their scientific and poetic value.

MAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

HAL (Le Centre pour la Communication Scientifique Directe), 2007

HAL (Le Centre pour la Communication Scientifique Directe), 2004

American Journal of Veterinary Research

To evaluate asymmetry in placement of bilateral skin markers on horses and to determine effect of... more To evaluate asymmetry in placement of bilateral skin markers on horses and to determine effect of asymmetric skin marker placement on kinematic variables for trotting horses. 10 horses for evaluation of asymmetry in marker placement; 1 horse for evaluation of effects on kinematic variables. Asymmetry in marker placement was assessed by attaching markers to horses and comparing radiographs of left and right limbs. An experimental model was developed to determine effects on kinematic variables; accuracy of the model was validated experimentally. Using kinematic data from a clinically normal trotting horse as reference data, effects of asymmetric marker placement on vertical displacement-time and joint angle-time diagrams were determined by use of the model. Asymmetry of placement was < 1 cm for markers on the distal portions of the limbs and < 2 cm for markers on the proximal portions. Asymmetric marker placement did not alter general shapes of the vertical displacement-time and...

Veterinary research

This study was conducted to evaluate a method for quantifying the flexion-extension movements of ... more This study was conducted to evaluate a method for quantifying the flexion-extension movements of the back of horses trotting on a track in the conditions of the clinical lameness examination. Using a 3-D kinematic analysis system, the successive positions of four markers placed at regular intervals between the withers and the tuber sacrale were recorded. To isolate the flexion-extension movements of the back, the positions of these four markers were recomputed in a trunk-related co-ordinate system of the horse. Then, for each frame, the equation of the third-order polynomial that best fitted the position of the four markers was determined. Using these equations, it was then possible to interpolate the vertical displacement of any point situated between the withers and the tuber sacrale. The accuracy of this method was evaluated using three additional markers placed between the four previous ones. The vertical displacements of these three markers were recorded and compared to the int...

Medical & Biological Engineering & Computing, 1996

Journal of Biomechanics, 1994

ITBM-RBM, 2003

Le système d'analyse cinématique ZEBRIS CMS-HS calcule, en temps réel, les coordonnées tridimensi... more Le système d'analyse cinématique ZEBRIS CMS-HS calcule, en temps réel, les coordonnées tridimensionnelles de marqueurs cinématiques en utilisant le principe de la triangulation ultrasonore. Cependant, la propagation des ondes ultrasonores peut être altérée par des facteurs extérieurs tels que les réflexions du signal, le vent, les variations de température. Pour chacune de ces conditions, les coordonnées 3D d'un système de six marqueurs immobiles ont été mesurées, permettant le calcul d'angles et de distances théoriquement invariables. La précision du système a été évaluée par la dispersion des valeurs autours de la moyenne calculée pour chaque série de mesures. Dans les conditions standard du laboratoire, la précision des mesures était de ± 0,14 mm sur les distances et ± 0,16°sur les angles. Des phénomènes de réflexion des ultrasons peuvent provoquer l'apparition d'erreurs systématiques de l'ordre de 0,2°et altèrent la répétabilité des mesures. Le vent diminue la précision des mesures proportionnellement à sa vitesse. La température ambiante influe sur l'exactitude des mesures. En conséquence, celle-ci doit être correctement paramétrée. La précision des mesures diminue en éloignant ou en décalant les émetteurs par rapport aux microphones lorsque la distance excède 1,5 m. Cette étude permet d'évaluer les causes d'imprécision de mesure pour le système et de définir les limites d'utilisation de celui-ci.

Equine Veterinary Journal, 1997

ABSTRACT This study of the locomotion symmetry was undertaken to provide standard symmetry indice... more ABSTRACT This study of the locomotion symmetry was undertaken to provide standard symmetry indices of a group of sound horses at the trot. Using a 3D data collection system, the kinematics of the limb joints of 13 clinically nonlame horses were recorded while trotting in the standard conditions of the clinical lameness examination. A kinematic symmetry indice based on an inter-correlation method was defined and applied to the vertical displacement-time and joint angle-time diagrams of the left and right joints of the horses. For each horse, the mean symmetry indice of each joint was calculated using values from 5 trials. For each joint, these means were then averaged. To evaluate the repeatability of the locomotion symmetry, the intra- and inter-individual variabilities of the symmetry indices were studied. The levels of symmetry of the markers of the trunk were generally lower than those of the limbs. Moreover, during the 5 trials these levels of symmetry were strongly variable but their mean values were very similar from one horse to another. In our experimental conditions the trunk presented a higher degree of freedom than the limbs. This high intra-individual variability indicated also that several trials are necessary to quantify the locomotion symmetry of a trotting horse. In the same way, a lower level of symmetry of the hindlimbs, compared to the forelimbs, was proved by their lower values of symmetry indices. As opposed to the supporting role of the forelimbs, the propulsive role of the hindlimbs may explain this feature.

Equine Veterinary Journal, 2010

ABSTRACT

Equine Veterinary Journal, 2001

This study was undertaken to describe the symmetry of movements of fore- and hindlimbs in horses ... more This study was undertaken to describe the symmetry of movements of fore- and hindlimbs in horses suffering from various spontaneous lamenesses. Two groups of horses were studied: 13 clinically sound horses and 24 lame horses. Using a 3-dimensional (3-D) kinematic analysis system, movements of both sides of each horse were recorded simultaneously while trotting on a track. The differences in motion between left and right homologous joints of each horse were quantified using symmetry indices based on an intercorrelation method. Symmetry indices obtained for each lame horse were then compared with those of sound horses. This comparison showed that the most sensitive lameness indicators were the symmetry indices of the vertical displacement of the proximal markers of the limbs. Symmetry indices of each lame horse were also compared with those of the other lame horses, using correlation coefficients to determine whether or not various lamenesses generate similar alterations of the locomotion symmetry. Values of these coefficients allowed 2 types of lameness to be distinguished. In 21 lame horses, the largest alterations in the symmetry of vertical movements were observed for the proximal markers of the limbs, which may reflect the supporting component of these lamenesses. In contrast, the asymmetries in vertical movements were more pronounced for the distal markers in 3 horses (one stringhalt and 2 carpal injuries), which may reflect the swinging component of these lamenesses. This cross-correlation method can be implemented easily in a computer programme and may represent a first step in the development of an expert system.

Equine Veterinary Journal, 2001

Many clinical reports have previously documented the advantages of plates or external fixations b... more Many clinical reports have previously documented the advantages of plates or external fixations but surgeons prefer to use plate for better acceptance by the owner, less dressing and a decreased rate of infection. In order to address complications of carpal surgery, infections, arthritis and osteomyelitis, external fixation is warranted. Twelve canine forelimbs, free of abnormality, were tested under compression to evaluate the in vitro biomechanical behaviour of the normal carpus. This behaviour was compared with that of a stabilized carpus stabilised by panarthrodesis with either plates (8 hole 3.5 mm dynamic compression plate (DCP), or a type II external fixator. Deformation vs. load was recorded after compression with a testing machine in conjunction with a digital data acquisition system. Yield load, maximal load to failure and stiffness were then calculated. Variables were significantly greater for arthrodesis with external fixation and plates than for intact forelimbs. The stiffness and the MLF after stabilisation with plates or external fixators did not differ significantly. At MLF, fracture of the third metacarpus appeared with plates, whereas deformations of the pins and bars of the external fixators increased with load. Stabilisation with plate or external fixation allowed more load to failure than the intact carpus. The biomechanical behaviour of both methods of arthrodesis was identical during loading. However, after rupture, external fixation was more plastic. External fixation, which is less often used than plates for pancarpal arthrodesis, mainly due to the occurrence of sepsis, may be useful for arthrodesis of the carpus in big or active dogs.

Equine Veterinary Journal, 2010

Sacroiliac joint (SIJ) disease is associated with poor hindlimb action, lameness and poor perform... more Sacroiliac joint (SIJ) disease is associated with poor hindlimb action, lameness and poor performance in horses. However, little is known about the biomechanics of this low-motion joint. To determine in vitro the capacities of movement of the SIJ in the sagittal plane, and to test the effect of a sacrosciatic and sacrotuberal desmotomy on its stabilisation. Six anatomical specimens underwent cycles of flexion-extension of the lumbosacral joint (LSJ) before and after desmotomy. Kinematic triads were linked rigidly to the sacrum, spinous process of vertebra L5 and iliac wing. Angles were measured using a joint coordinate system based on anatomical frames. The LSJ underwent regular movements of flexion and extension (overall mean +/- s.d. range 23.4 +/- 1.6 degrees). The only recorded movement of the SIJ was a nutation during LSJ flexion (overall mean +/- s.d. 0.8 +/- 0.5 degrees). Desmotomy induced an increase of that nutation (overall mean +/- s.d. 1.7 +/- 0.2 degrees). Movements of the SIJ were small and coupled only with the flexion of the LSJ. The ligaments surrounding the SIJ have a strong effect on the stabilisation of this joint. Due to the limited amount of movement, its biomechanical study in vivo seems to be difficult. Further in vitro studies would be useful to determine the role of each ligament, to better understand the clinical consequences of the tears frequently observed during necropsy.

Archives of Physiology and Biochemistry, 1995

Archives of Physiology and Biochemistry, 1995

The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden.

P r é s e n t a t i o n d e l ' é d i t e u r Jusqu'au XIXe siècle la formation des médec... more P r é s e n t a t i o n d e l ' é d i t e u r Jusqu'au XIXe siècle la formation des médecins en anatomie comportait un incontournable : la dissection de corps humains ou animaux. Avec le risque toujours important de la piqure anatomique transmetteuse de germes et surtout la difficulté grandissante à se procurer des corps. Il existait bien des modèles anatomiques en cire mais lourds chers et peu pratiques ils étaient peu utilisés. C'est alors que le docteur Auzoux mit au point un procédé révolutionnaire par sa simplicité : la fabrication de corps en papier mâché. Grâce à d'habiles charnières on pouvait retirer peau muscles organes viscères. L'anatomie clastique était née. Auzoux proposa différents modèles ainsi que des détails. Puis il passa à des modèles animaliers puis végétaux gardant toujours en tête l'éducation des médecins ou des vétérinaires mais aussi des masses. L'entreprise Auzoux connut alors un succès commercial important et une diffusion inter...