Eyelid fat grafting: indications, operative technique and complications; a systematic review

International audienceIntroduction - Many recent studies concerning autologous fat grafting in the eyelids have been published, mostly consisting of case reports and retrospective case series. However, no study on the overall complication or satisfaction rate associated with the various grafting techniques exists. We performed a comprehensive literature review to determine the outcomes and complications of eyelid fat grafting, as well as patient satisfaction.Methods - A systematic review of the literature using the PRISMA criteria was conducted. This protocol was registered at the Prospective Register of Systematic Reviews at the National Institute for Health Research.Results - Sixteen studies, representing 1,159 patients and published between June 2004 and December 2014, were included. Satisfactory results, judged by clinical examination, were observed in all studies. Few postoperative complications were reported.Conclusions - We demonstrated that the procedures were easy to perform, and achieved satisfactory and sustainable results with few complications in both reconstructive and cosmetic surgery. However, a wide disparity exists in the various fat harvesting, fat purification, and reinjection techniques. Further studies are required to assess the long-term outcomes. Our conclusions should be accepted cautiously due to the small number of articles and the lack of evidence in published studies.<br

De l'analyse du mouvement in-vitro à la génération de mouvements des systèmes anthropomorphes

National audienc

Development of a wearable framework for the assessment of a mechanical-based indicator of falling risk in the field

International audienceThis paper presents both normative thresholds of the distance ofthe Body Center of Mass (BCOM) to the Minimal Moment Axis(MMA) during able-bodied level walking that can be used as a proxyof whole-body angular momentum variations to characterize theinstability of gait and a wearable framework to assess this indicatorin the field. The results are based on experimental analysis of thegait of able-bodied subject from a motion capture system and on apreliminary comparison of wearable-based against optoelectronic-based assessment of gait instability in one asymptomatic subject andone person with transfemoral amputation

Cycling Biomechanics and Its Relationship to Performance

International audienceState-of-the-art biomechanical laboratories provide a range of tools that allow precise measurements of kinematic, kinetic, motor and physiologic characteristics. Force sensors, motion capture devices and electromyographic recording measure the forces exerted at the pedal, saddle, and handlebar and the joint torques created by muscle activity. These techniques make it possible to obtain a detailed biomechanical analysis of cycling movements. However, despite the reasonable accuracy of such measures, cycling performance remains difficult to fully explain. There is an increasing demand by professionals and amateurs for various biomechanical assessment services. Most of the difficulties in understanding the link between biomechanics and performance arise because of the constraints imposed by the bicycle, human physiology and musculo-skeletal system. Recent studies have also pointed out the importance of evaluating not only output parameters, such as power output, but also intrinsic factors, such as the cyclist coordination. In this narrative review, we present various techniques allowing the assessment of a cyclist at a biomechanical level, together with elements of interpretation, and we show that it is not easy to determine whether a certain technique is optimal or not

Analyse dynamique tridimensionnelle du pénalty au handball selon le niveau d’expertise et la zone ciblée

Le but de cette étude est de mettre en évidence des différences d’organisation du mouvement lors du pénalty au handball en fonction du niveau d’expertise et de la zone de tir. Six personnes expertes et huit personnes novices ont effectué un enchaînement de tirs dans différentes zones de l’embut. Les données cinématiques des segments des joueurs ont été enregistrées à l’aide d’un système d’analyse du mouvement tridimensionnelle (VICON). Les résultats ont dévoilé une vitesse de balle plus grande pour les tirs ciblant la partie basse de l’embut (18,6 ± 0,7 et 18,4 ± 0,8 m/s contre 17 ± 0,6 et 17,5 ± 0,7 m/s). Les moments résultants obtenus par dynamique inverse au niveau du poignet (1,1 ± 0,6 Nm contre  −0,4 ± 0,3 Nm) et du coude (7,9 ± 5,9 Nm contre  −10,5 ± 7,3 Nm) ont permis de différencier les experts et les novices. L’organisation du mouvement est dépendante de la zone ciblée et du niveau d’expertise

Gait cycle modeling in cerebral palsy condition

International audienceAutonomous gait is a fundamental element for access to independent life and avoiding the de-socialization of people with motor disabilities. In this context, this research is part of the EXOKID project which aims at designing a personalized exoskeleton for children with cerebral palsy. For such personalisation, two 9 years old twin sisters, one with spastic cerebral palsy (C) and a healthy one (H) without any impairments, performed several walks with electromyography (EMG), kinematics and force acquisitions. This paper presents a model of the knee and hip's spastic angular displacement of C during a walk using mechanical differential equations. Two models were designed: one based on the timing of the muscular activation, the other where the timing is defined using a genetic algorithm (GA). These models highlight the spastic contributions of the muscles involved in the walk (agonists and antagonists of the joints studied) and their activations. The amplitude of the activations for both models was carried out using GA. Gait cycles were modeled with a determination coefficient (R 2) higher than 84% for both models

Modification of the spontaneous seat-to-stand transition in cycling with bodyweight and cadence variations

International audienceWhen a high power output is required in cycling, a spontaneous transition by the cyclist from a seated to a standing position generally occurs. In this study, by varying the cadence and cyclist bodyweight, we tested whether the transition is better explained by the greater power economy of a standing position or by the emergence of mechanical constraints that force cyclists to stand. Ten males participated in five experimental sessions corresponding to different bodyweights (80%, 100%, or 120%) and cadences (50 RPM, 70 RPM, or 90 RPM). In each session, we first determined the seat-to-stand transition power (SSTP) in an incremental test. The participants then cycled at 20%, 40%, 60%, 80%, 100%, or 120% of the SSTP in the seated and standing positions, for which we recorded the saddle forces and electromyogram (EMG) signals of eight lower limb muscles. We estimated the cycling cost using an EMG cost function (ECF) and the minimal saddle forces in the seated position as an indicator of the mechanical constraints.Our results show the SSTP to vary with respect to both cadence and bodyweight. The ECF was lower in the standing position above the SSTP value (i.e., at 120%) in all experimental sessions. The minimal saddle forces varied significantly with respect to both cadence and bodyweight.These results suggest that optimization of the muscular cost function, rather than mechanical constraints, explain the seat-to-stand transition in cycling

Spasticity model based on muscular activations using genetic algorithm

International audienc

Inverse Optimal Control to Model Human Trajectories During Locomotion

International audienceCobotic applications require a good knowledge of human behaviour in order to be cleverly, securely and fluidly performed. For example, to make a human and a humanoid robot perform a co-navigation or a co-manipulation task, a model of human walking trajectories is essential to make the robot follow or even anticipate the human movements. This paper aims to study the Center of Mass (CoM) path during locomotion and generate human-like trajectories with an optimal control scheme. It also proposes a metric which allows to assess this model compared to the human behaviour. CoM trajectories during locomotion of 10 healthy subjects were recorded and analysed as part of this study. Inverse optimal control was used to find the optimal cost function which best fits the model to the measurements. Then, the measurements and the generated data were compared in order to assess the performance of the presented model. Even if the experiments show a great variability in human behaviours, the model presented in this study gives an accurate approximation of the average human walking trajectories. Furthermore, this model gives an approximation of human locomotion good enough to improve cobotic tasks allowing a humanoid robot to anticipate the human behaviour

Comparison of muscles activity of two twins, one with cerebral palsy

International audienc