As the incidence of diagnosed carpal tunnel syndrome continues to increase, an understanding of the mechanism(s) of insult to the median nerve which leads to its development becomes ever more imperative. Knowledge of the exact cause of CTS could lead to improved diagnostic and treatment methods, or more importantly, to better preventative measures. The goal of this study was to investigate movements and interactions of structures within the carpal tunnel during wrist flexion and hand loading in order to obtain information about a specific mechanism of insult to the median nerve. Symptomatic and normal subjects were compared to observe differences in the interactions of the median nerve and its surrounding structures. A new methodology was developed to facilitate the evaluation of these populations.

Carpal tunnel syndrome is a frequently encountered chronic peripheral nerve entrapment disorder caused by mechanical insult to the median nerve, which may occur from impingement by the surrounding digital flexor tendons and the tunnel boundaries. Anatomic finite element models of the carpal tunnel provide a method to evaluate the potential contact stresses that may develop on the median nerve between the digital flexor tendons and tunnel boundaries. Realistic finite element simulations are dependent upon the use of physiologically accurate material properties. The purpose of this work was to ascertain material properties for the digital flexor tendons, median nerve and transverse carpal ligament to inform finite element simulations. The compressive mechanical behavior of the digital flexor tendons, median nerve and transverse carpal ligament was characterized under functionally relevant axial tensile loads. These properties can now be implemented into full scale finite element models of the carpal tunnel to evaluate the mechanism of insult to the median nerve leading to the development of carpal tunnel syndrome.

Nitric oxide is a small free radical generated by family of enzymes, the nitric oxide synthases. In a series of experiments performed over the last 15 years we showed that nitric oxide is induced by all three isoforms of nitric oxide synthase during tendon healing and that it plays a crucial beneficial role in restoring tendon function. In normal tendon we found very little nitric oxide synthase activity while in injured rat and human tendons nitric oxide synthase activity was expressed in healing fibroblasts in a temporal fashion. In healing rat Achilles tendon fibroblasts the first isoform to be expressed was endothelial nitric oxide synthase (eNOS), followed by inducible nitric oxide synthase (iNOS), and then brain or neuronal nitric oxide synthase (bNOS). Systemic inhibition of nitric oxide synthase activity decreased the cross sectional area and mechanical properties of the healing rodent Achilles tendons. Addition of nitric oxide via NO-flurbiprofen or NO-paracetamol enhanced rat Achilles tendon healing. Addition of nitric oxide to cultured human tendon cells via chemical means and via adenoviral transfection enhanced collagen synthesis, suggesting that one mechanism for the beneficial of nitric oxide on tendon healing might be via matrix synthesis. The final part of the work involved three randomized, double-blind clinical trials which evaluated the efficacy of nitric oxide donation via a patch in the management of the tendinopathy. In all three clinical trials there was a significant positive beneficial effect of nitric oxide donation to the clinical symptoms and function of patients with Achilles tendinopathy, tennis elbow and Achilles tendonitis.

La modélisation du comportement mécanique de l'architecture musculo-squelettique sollicitée in situ constitue un enjeu tant en biomécanique, en réhabilitation, qu'en physiologie. Ceci nécessite d'évaluer des variables non directement mesurables comme les moments et les forces musculaires. Ces variables peuvent être estimées à partir de la conception de modèles biomécaniques qui nécessitent la formulation de certaines hypothèses et l'enregistrement de données expérimentales périphériques. Or, le système musculo-squelettique est redondant dans le sens où chaque degré de liberté est sous le contrôle de plusieurs actionneurs (muscles) aussi bien agonistes qu'antagonistes. L'utilisation conjointe de la modélisation biomécanique des systèmes musculaires et de l'optimisation numérique nous a permis de résoudre ce problème de redondance. Particulièrement dans ce travail, nous avons développé des techniques de modélisation et d'expérimentation permettant l'analyse des tensions des tendons mobilisant le doigt dans différentes situations de sollicitation. Ceci nous a permis de montrer que l'amplitude des moments passifs non musculaires ne devait pas être négligée dans les procédures de calcul. De plus, nous avons également utilisé de façon originale l'information EMG sous forme d'une contrainte d'inégalité dans les procédures d'optimisation. Ce travail a permis de mettre en évidence des résultats inédits concernant la distribution des tensions dans les tendons agonistes et antagonistes. Diverses adaptations du modèle sont discutées dans le document, la substitution de l'EMG invasif par de l'EMG de surface étant l'axe de recherche principal.

Tez (Uzmanlık) - Süleyman Demirel Üniversitesi, Tıp Fakültesi, Ortopedi ve Travmatoloji Anabilim Dalı, 2008. / Kaynakça var.

Un des freins majeurs au développement de la manipulation d'objet avec une main robotisée est sans aucun doute leur fragilité. C'est l'une des raisons pour laquelle un système bras-main anthropomorphe, extrêmement robuste, est développé au centre de robotique et de mécatronique de DLR. Le système est unique à la fois par sa complexité, utilisant 52 moteurs et plus de200 capteurs, ainsi que par ses capacités dynamiques. En effet, ce nouveau système a la particularité d'être mécaniquement flexible ce qui offre la possibilité de stocker de l'énergie à court terme et remplit ainsi deux fonctions essentielles pour un robot humanoïde: les impacts sont filtrés et les performances dynamiques sont augmentées.Dans cette thèse, on se concentre plus particulièrement sur la main. Elle dispose de 19 degrés de liberté dont chacun est actionné par deux tendons flexibles antagonistes. La rigidité des tendons étant non linéaire il est possible, tout comme peut le faire l'être humain, de co-contracter les <> et donc d'ajuster la rigidité des doigts afin de s'adapter au mieux aux tâches à effectuer. Cependant, cette flexibilité entraine de nouveau défis de modélisation et de contrôle. L'état de l'art se concentre majoritairement sur le problème de la répartition des forces internes ou du contrôle d'articulation flexible mais peu de travaux considèrent les deux problèmes simultanément.Le travail présenté dans la première partie de la thèse se concentre sur la modélisation de la main et du poignet. Les problématiques spécifiques aux systèmes actionnés par des tendons, tels que les matrices de couplage et l'estimation du déplacement des articulations à partir du déplacement des tendons, sont étudiées.La seconde partie se concentre sur le contrôle d'articulations actionnées par des tendons flexibles antagonistes. Les problèmes de distribution des forces internes et de correction de la rigidité perçue par l'utilisateur sont présentés.Des approches de contrôle linéaire et non linéaire sont utilisées et des expériences sont réalisées pour comparer ces approches. En particulier, il est montré que le <>, une méthode de contrôle non linéaire peut être utilisée et permet d'obtenir le comportement d'impédance souhaité tout en garantissant la stabilité en boucle fermée.

Collagen content and cross-linking are believed to be major determinants of tendon structural integrity and function. Gender and chronic resistance training have been shown to alter tendon function, and may also alter these key structural features of tendon. Patellar tendon biopsies were taken from untrained men (M, n=8, 25±1 y, 1RM: 53±3 kg), untrained women (W, n=8, 23±2 y, 1RM: 29±2 kg), and resistance-trained (10±1 y trained) men (RTM, n=8, 24±2 y, 1RM: 71 ±6 kg). Biopsies were analyzed for dry mass, collagen content, and collagen cross-linking (hydroxylysylpyridinoline, HP). Tendon dry mass was significantly lower in women than men (M: 376±8, W: 343±5 µg dry mass/mg tendon wet wt, P<0.01), and was not influenced by chronic resistance training (RTM: 364±20 µg dry mass/mg tendon wet wt, P>0.05). The lower tendon dry mass in women reduced (P=0.08) collagen content per tendon wet weight (M: 339±14, W: 306±11 µg collagen/mg tendon wet wt). Collagen content of tendon dry mass was not influenced by gender (P>0.05) or resistance training (P>0.05) (M: 903±38, W: 892±29, RTM: 881±43 !,g collagen/mg tendon dry mass). Similarly, cross-linking of collagen was not impacted by gender (P>0.05) or training (P>0.05) (M: 401±47, W: 418±35, RTM: 424±38 mmol HP/mol collagen). In women, the overall lower amount of collagen per tendon wet weight may explain gender differences in tendon function, while collagen content and cross-linking of the dry mass are remarkably consistent across gender and training status. / School of Physical Education, Sport, and Exercise Science

This thesis compares the consumption of primary superstructure material in a conventional single span CPCI system with those of double-T alternatives. The CPCI system is currently the preferred bridge type for short and medium spans in Canada, despite its relatively inefficient use of materials due to imperfect live load sharing among multiple parallel girders. The double-T alternatives utilize slender double-T cross-sections, fully precast segments, and post-tensioning in both longitudinal and transverse direction. The economy of the CPCI and double-T systems is compared within the framework of four sample designs. The results indicate that the double-T systems are in general more efficient than the CPCI system and have the potential to achieve better economy.

An alternative structural system for short span bridges is presented: a precast segmental double-T with external, unbonded post-tensioning tendons. Single-span designs from 20 to 45 m long show that the system can be implemented over a wide range of spans and that the system’s sensitivity to post-tensioning losses reported in previous literature can be reduced by aligning the prestressing force more concentrically. Designs for multi-span bridges using this system are presented using simply supported spans connected by thin flexible linking slabs made of ultra high-performance fibre-reinforced concrete and using sections made fully continuous over intermediate supports. A simplified method of geometry control is presented to facilitate the proper alignment of precast segments without the use of match casting. The precast segmental double-T bridge is compared to sixteen existing slab on girder bridges and found to be a competitive alternative in terms of material use, cost, construction schedule, and aesthetic merit.

This thesis compares the consumption of primary superstructure material in a conventional single span CPCI system with those of double-T alternatives. The CPCI system is currently the preferred bridge type for short and medium spans in Canada, despite its relatively inefficient use of materials due to imperfect live load sharing among multiple parallel girders. The double-T alternatives utilize slender double-T cross-sections, fully precast segments, and post-tensioning in both longitudinal and transverse direction. The economy of the CPCI and double-T systems is compared within the framework of four sample designs. The results indicate that the double-T systems are in general more efficient than the CPCI system and have the potential to achieve better economy.