Montceau-les-Mines, France


Montceau-les-Mines, France
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Perrier A.,CNRS Complex Medical Engineering Laboratory | Perrier A.,Joseph Fourier University | Vuillerme N.,Joseph Fourier University | Vuillerme N.,Institut Universitaire de France | And 8 more authors.
IRBM | Year: 2014

Objectives Most foot ulcers are the consequence of a trauma (repetitive high stress, ill-fitting footwear, or an object inside the shoe) associated to diabetes. They are often followed by amputation and shorten life expectancy. This paper describes the prototype of the Smart Diabetic Socks that has been developed in the context of the French ANR TecSan project. The objective is to prevent pressure foot ulcers for diabetic persons. Material and methods A fully wireless, customizable and washable "smart sock" has been designed. It is made of a textile which fibers are knitted in a way they provide measurements of the pressure exerted under and all around the foot in real-life conditions. This device is coupled with a subject-specific Finite Element foot model that simulates the internal strains within the soft tissues of the foot. Results A number of derived stress indicators can be computed based on that analysis, such as the accumulated stress dose, high internal strains or peak pressures near bony prominences during gait. In case of risks for pressure ulcer, an alert is sent to the person and/or to the clinician. A watch, a smart-phone or a distant laptop can be used for providing such alert. © 2014 Elsevier Masson SAS.

Semere A.,Grenoble University Hospital Center | Semere A.,University Grenoble Alpes | Payan Y.,French National Center for Scientific Research | Cannard F.,Texisense | And 4 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Post-traumatic median nerve sensitive deficits are frequent. They are a source of permanent handicap that dramatically decreases the level of autonomy and the quality of life of persons suffering from these deficits. Surgical repair is possible, but the results are not always functionally useful. Therefore, prosthetic approaches do represent an alternative solution that needs to be explored. Along these lines, this paper describes an innovative home-based hand rehabilitation system device that exploits sensory substitution of median sensory deficits in the traumatized hand. It is composed of a glove bearing smart textile pressure sensors and a wristband providing vibratory biofeedback to the user. The goal of this sensory-substitution system is to provide for patients an effective method to compensate the lack of sensitivity of the finger pads and to recover a functional hand use. This innovative system is intended to be employed for assessment, training and rehabilitation exercises at home. © Springer International Publishing Switzerland 2015.

Luboz V.,CNRS Complex Medical Engineering Laboratory | Perrier A.,Laboratoires TIMC IMAG et AGIM | Stavness I.,University of British Columbia | Lloyd J.E.,University of British Columbia | And 7 more authors.
Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization | Year: 2013

Foot ulcers are a common complication of diabetes and are the consequence of trauma to the feet and a reduced ability to perceive pain in persons with diabetes. Ulcers appear internally when pressures applied on the foot create high-internal strains below bony structures. It is therefore important to monitor tissue strains in persons with diabetes. We propose to use a biomechanical model of the foot coupled with a pressure sensor to estimate the strains within the foot and to determine whether they can cause ulcer formation. Our biomechanical foot model is composed of a finite element mesh representing the soft tissues, separated into four Neo-Hookean materials with different elasticity: plantar skin, non-plantar skin, fat and muscles. Rigid body models of the bones are integrated within the mesh to rigidify the foot. Thirty-three joints connect those bones around cylindrical or spherical pivots. Cables are included to represent the main ligaments in order to stabilise the foot. This model simulates a realistic behaviour when the sole is subjected to pressures measured with a sensor during bipedal standing. Surface strains around 5% are measured below the heel and metatarsal heads, while internal strains are close to 70%. This strain estimation, when coupled to a pressure sensor, could consequently be used in a patient alert system to prevent ulcer formation. © 2013, Taylor & Francis.

Luboz V.,CNRS Complex Medical Engineering Laboratory | Perrier A.,CNRS Complex Medical Engineering Laboratory | Bucki M.,TexiSense | Diot B.,IDS Inc | And 4 more authors.
Annals of Biomedical Engineering | Year: 2015

Most posterior heel ulcers are the consequence of inactivity and prolonged time lying down on the back. They appear when pressures applied on the heel create high internal strains and the soft tissues are compressed by the calcaneus. It is therefore important to monitor those strains to prevent heel pressure ulcers. Using a biomechanical lower leg model, we propose to estimate the influence of the patient-specific calcaneus shape on the strains within the foot and to determine if the risk of pressure ulceration is related to the variability of this shape. The biomechanical model is discretized using a 3D Finite Element mesh representing the soft tissues, separated into four domains implementing Neo Hookean materials with different elasticities: skin, fat, Achilles’ tendon, and muscles. Bones are modelled as rigid bodies attached to the tissues. Simulations show that the shape of the calcaneus has an influence on the formation of pressure ulcers with a mean variation of the maximum strain over 6.0 percentage points over 18 distinct morphologies. Furthermore, the models confirm the influence of the cushion on which the leg is resting: a softer cushion leading to lower strains, it has less chances of creating a pressure ulcer. The methodology used for patient-specific strain estimation could be used for the prevention of heel ulcer when coupled with a pressure sensor. © 2014, Biomedical Engineering Society.

Luboz V.,CNRS Complex Medical Engineering Laboratory | Petrizelli M.,CNRS Complex Medical Engineering Laboratory | Bucki M.,TexiSense | Diot B.,IDS Inc | And 4 more authors.
Journal of Biomechanics | Year: 2014

With 300,000 paraplegic persons only in France, ischial pressure ulcers represent a major public health issue. They result from the buttocks' soft tissues compression by the bony prominences. Unfortunately, the current clinical techniques, with - in the best case - embedded pressure sensor mats, are insufficient to prevent them because most are due to high internal strains which can occur even with low pressures at the skin surface. Therefore, improving prevention requires using a biomechanical model to estimate internal strains from skin surface pressures. However, the buttocks' soft tissues' stiffness is still unknown. This paper provides a stiffness sensitivity analysis using a finite element model. Different layers with distinct Neo Hookean materials simulate the skin, fat and muscles. With Young moduli in the range [100-500. kPa], [25-35. kPa], and [80-140. kPa] for the skin, fat, and muscles, respectively, maximum internal strains reach realistic 50 to 60% values. The fat and muscle stiffnesses have an important influence on the strain variations, while skin stiffness is less influent. Simulating different sitting postures and changing the muscle thickness also result in a variation in the internal strains. © 2014 Elsevier Ltd.

Bucki M.,TexiSense | Luboz V.,TexiSense | Perrier A.,TexiSense | Perrier A.,French National Center for Scientific Research | And 6 more authors.
Medical Engineering and Physics | Year: 2016

Foot pressure ulcers are a common complication of diabetes because of patient's lack of sensitivity due to neuropathy. Deep pressure ulcers appear internally when pressures applied on the foot create high internal strains nearby bony structures. Monitoring tissue strains in persons with diabetes is therefore important for an efficient prevention. We propose to use personalized biomechanical foot models to assess strains within the foot and to determine the risk of ulcer formation. Our workflow generates a foot model adapted to a patient's morphology by deforming an atlas model to conform it to the contours of segmented medical images of the patient's foot. Our biomechanical model is composed of rigid bodies for the bones, joined by ligaments and muscles, and a finite element mesh representing the soft tissues. Using our registration algorithm to conform three datasets, three new patient models were created. After applying a pressure load below these foot models, the Von Mises equivalent strains and "cluster volumes" (i.e. volumes of contiguous elements with strains above a given threshold) were measured within eight functionally meaningful foot regions. The results show the variability of both location and strain values among the three considered patients. This study also confirms that the anatomy of the foot has an influence on the risk of pressure ulcer. © 2016.

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