La connaissance de l’anatomie des muscles paravertébraux lombaires et la compréhension de leur mode d’action représentent un enjeu majeur de la prise en charge des lombalgies. L’expérience chirurgicale montre que les muscles paravertébraux constituent une volumineuse masse musculaire dépourvue de gros tendons et engainée dans un fascia inextensible. En biomécanique, la force maximale d’un muscle est positivement corrélée à la surface de section des tendons et du corps charnu. Il existe probablement, au niveau lombaire, une étonnante discordance entre le volume musculaire, qui suggère une force élevé, et celui des tendons dont la résistance mécanique est très limitée. Les modèles biomécaniques classiques semblent inappropriées pour décrire le mode d’action des muscles paravertébraux. Selon certains modèles biomécaniques dérivés de la théorie des poutres, l’augmentation de la dureté ou élasticité au sein du compartiment paravertébral serait le mécanisme principal de la stabilisation de la colonne vertébrale.Ces travaux se sont articulés autour de deux grands axes. L’axe anatomique avait pour objectif de vérifier l’hypothèse de la discordance morphologique tendon/muscle des principaux muscles paravertébraux lombaires. L’axe radiologique avait pour objectif la mise en place de protocoles d’élastographie par résonance magnétique et ultrasonore pour l’exploration de l’élasticité des différents muscles paravertébraux lombaires au repos et dans plusieurs postures différentes.Les résultats des travaux anatomiques montrent un ratio de surface tendon/muscle du multifudus et de l’iliocostalis extrêmement bas et une petite surface de section du multifidus suggérant que muscles ne sont pas capables de générer l’extension dorsale de la colonne lors de la contraction musculaire. Ils semblent plutôt stabiliser la colonne vertébrale en lui assurant une certaine rigidité assurée par un volume musculaire conséquent confiné dans une loge inextensible. Au moyen de l’élastographie, nous montrons que l’élasticité des muscles paravertébraux est la plus basse au repos, en décubitus et qu’elle n’est pas influencée par la flexion ou l’extension passive de la colonne, ni par l’étirement du fascia thoracolombaire. L’élasticité augmente lors des positions : assise, debout, penchée en avant et en arrière. Le comportement biomécanique de chaque muscle est différent selon les postures. Ces travaux confirment qu’il existe des modifications significatives de l’élasticité lors de la mise en charge de la colonne. Les lombalgies sont associées à des modifications d’élasticité de la colonne et des muscles paravertébraux observées lors de l’examen clinique, l’élastographie pourrait permettre de les explorer et de les caractériser de façon objective et non invasive. / Knowledge about the anatomy and the mode of action of the lumbar paraspinal muscles is major importance for the management of low back pain. Surgical experience shows that the paraspinal muscles constitute a voluminous muscle mass without large tendons and enclosed in an inextensible fascia. In biomechanics, the maximum strength of a muscle is positively correlated to the cross-sectional area of tendons and the muscle belly. Therefore, there is a paradox between the presumed high strength of the voluminous muscle belly and the low strength of the tendons. Traditional biomechanical models seem inappropriate for describing the mode of action of the paraspinal muscles. According to the beam theory, increasing elasticity within the paraspinal compartment would allow the stabilization of the spine.The work has two broad objectives. The first objective was to assess the assumption that there is an inconsistency betwenn the cross-sectional area of the tendon and of the belly of the main paraspinal muscles, i.e. the multifidus, the longissius and the iliocostalis. The second objective was to establish elastography protocols with magnetic resonance imaging and ultrasonography for the exploration of the elasticity of the paraspinal muscles at rest and in several different postures. Results of the anatomical studies show that the tendon-to-muscle area ratios of the longissimis and the iliocostalis were extremely small, as well as cross-sectional area of the belly of the multifidus. That suggests that paraspinal muscles are not able to provide the dorsal extension of the spine during muscle contraction. Rather, they seem to stabilize the spine by providing it with a certain rigidity ensured by a substantial muscle volume contained in an inextensible compartment. Through elastography, we have shown that the elasticity of the paraspinal muscles was the lowest at rest, in decubitus. Elasticity was not influenced by passive flexion or extension of the spine, nor by the stretching of the thoracolumbar fascia. Elasticity increased during sitting, standing, bending forward and bending backward the compared to decubitus. The biomechanical behaviour of the longissimus, the iliocostalis and multifidus differed according to the postures. This work confirms that there are significant changes in elasticity during standing postures. Low back pain is associated with stiffness changes of the spine and of the paraspinal muscles that have been observed through clinical examination. In the future, elastography could allow exploring low back pain.

京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第21042号 / 人健博第58号 / 新制||人健||4(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 坪山 直生, 教授 黒木 裕士, 教授 松田 秀一 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

No description available.

Objective: To determine the difference in effectiveness of positional release therapy (PRT) compared with therapeutic massage (TM) in treating trigger and tender points in the upper trapezius muscle. Background: Trigger points in the upper trapezius muscle are common and can be painful. Therapeutic massage is a more traditional treatment method for this condition while PRT is relatively new. Design and Setting: A randomized-group design was used to examine the differences between the 2 treatments for reducing pain and muscle tension. Subjects: Sixty healthy subjects (males = 24, females = 36; age = 27.1 ± 8.8 years; wt = 75.2 ± 17.9 kg; ht = 172.8 ± 9.7 cm) presenting with upper trapezius pain and a trigger point. Subjects were randomly assigned to the TM group or the PRT group. Measurements: Presence of upper trapezius trigger points was found via palpation by a clinician. Level of pain was measured by a visual analog scale (VAS) and pain pressure threshold (PPT) was assessed by a pressure algometer. Muscle thickness was measured by B-mode ultrasound (US) and muscle tension was measured by shear-wave elastography (SWE). Subjects were measured pretreatment and posttreatment and 48 hours later. Results: All measurements showed significant improvements for both treatments. Positional release therapy was more effective (p = 0.05) at reducing pain at day 2 and was able to maintain the pain loss. The SWE and US showed no difference between the treatment groups. There was no significant difference in PPT, but PRT PPT increased each visit while TM dropped significantly at day 2 (p = .003). Conclusion: Both treatments showed a significant ability to reduce pain and acutely decrease muscle stiffness (as measured by SWE) but there were few differences between the treatments. However, there appeared to be a slight benefit for pain reduction with PRT up to 2 days posttreatment.

Objective: To determine the difference in effectiveness of positional release therapy (PRT) compared with therapeutic massage (TM) in treating trigger and tender points in the upper trapezius muscle. Background: Trigger points in the upper trapezius muscle are common and can be painful. Therapeutic massage is a more traditional treatment method for this condition while PRT is relatively new. Design and Setting: A randomized-group design was used to examine the differences between the 2 treatments for reducing pain and muscle tension. Subjects: Sixty healthy subjects (males = 24, females = 36; age = 27.1 ± 8.8 years; wt = 75.2 ± 17.9 kg; ht = 172.8 ± 9.7 cm) presenting with upper trapezius pain and a trigger point. Subjects were randomly assigned to the TM group or the PRT group. Measurements: Presence of upper trapezius trigger points was found via palpation by a clinician. Level of pain was measured by a visual analog scale (VAS) and pain pressure threshold (PPT) was assessed by a pressure algometer. Muscle thickness was measured by B-mode ultrasound (US) and muscle tension was measured by shear-wave elastography (SWE). Subjects were measured pretreatment and posttreatment and 48 hours later. Results: All measurements showed significant improvements for both treatments. Positional release therapy was more effective (p = 0.05) at reducing pain at day 2 and was able to maintain the pain loss. The SWE and US showed no difference between the treatment groups. There was no significant difference in PPT, but PRT PPT increased each visit while TM dropped significantly at day 2 (p = .003). Conclusion: Both treatments showed a significant ability to reduce pain and acutely decrease muscle stiffness (as measured by SWE) but there were few differences between the treatments. However, there appeared to be a slight benefit for pain reduction with PRT up to 2 days posttreatment.

In the past decade there has been a significant increase in focus on the effect upper body vibration (UBV) has on the recovery of skeletal muscle after exercise-induced muscle damage. Recovery can be defined and investigated using a wide variety of methods. This study used three different measurements to track muscle recovery over 7 days following an exercise muscle damage protocol and applied vibration to a mathematical model. A visual analog scale (VAS) was used to measure muscle pain, a strain gauge was used to obtain maximum voluntary isometric contraction (MVIC) strength measurements, and shear wave elastography (SWE) represented muscle stiffness over the 7-day experiment. Thirty-three participants were divided into three groups. The first was a control group (C) that experienced no exercise and no therapy. The no vibration group (NV) performed the damage an exercise protocol but received no therapy. The vibration group (V) performed the same exercise protocol but also received vibration therapy. The exercise protocol consisted of 100 dumbbell curls at starting at 50% of their MVIC with one minute of rest after each set of ten. The data provided convincing evidence (27.2%, p < 0.0001) that group NV was not back to its normal stiffness after 7 days unlike group V, which was shown not to be any different from its baseline at the end of the week (9.15%, p = 0.137). Three vibration factors (����1, ����2, ����3) were added to a skeletal muscle regeneration model (SK) to simulate how vibration affects muscle regeneration. The three factors were determined by analyzing previous research to understand how vibration affects cells in the regeneration process. Adding these into SK decreased the time to recovery from about 13 days to about 7 days. Recovery was defined by reaching 10% of the original number of myofibers within the damaged muscle.

No description available.

No description available.

京都大学 / 新制・課程博士 / 博士(人間健康科学) / 甲第24097号 / 人健博第104号 / 新制||人健||7(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 黒木 裕士, 教授 青山 朋樹, 教授 松田 秀一 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

Mechanical properties of muscle tissue are linked to its function. Magnetic Resonance Elastography (MRE) has the capability toquantitively measure these mechanical properties of soft tissue in-vivo. However, most MRE methods assume tissue isotropy during MRE reconstruction which is not an appropriate assumption for muscle tissue. To obtain tissue mechanical properties with higher accuracy, muscle anisotropy must be considered during MRE reconstruction. Therefore, the aim of this thesis was to implement an anisotropic MRE reconstruction. The anisotropic MRE reconstruction used solves three independent viscoelastic parameters (G||, G⊥, E||), that is based on a transverse isotropic (TI) inversion. The reconstruction was validated in a phantom study by comparison with an isotropic reconstruction, and in-vivo on gastrocnemius (ankle plantar flexor) and tibialis anterior (ankledorsi flexor) of one human subject. Also, a TI phantom was created to be included in the phantom study along with a commercial isotropic phantom. However, due to poor image quality, the TI phantom was excluded from further validation. Results from the isotropic phantom did not agree with the assumption of equal shear modulus in different planes of the isotropic medium. In-vivo study showed that the anisotropic reconstruction yielded mean moduli values in the range of what the literature suggests. The unequal shear modulus and young's modulus G||≠G⊥≠E|| of anisotropy in TI material was observed, indicating that the reconstruction method was able to identify the anisotropy ofmuscle tissue. However, further analysis including more human subjects are needed to conclude the reliability of the reconstruction method. / Muskelvävnadens mekaniska egenskaper är kopplade till dess funktion. Magnetresonans-Elastografi (MRE) har förmågan att kvantitativt mätadessa mekaniska egenskaper i mjukvävnad in-vivo. De flesta MRE metoder antar dock att vävnaden är isotropisk under MRE rekonstruktionen, vilket inte är ett lämpligt antagande för muskelvävnad. För att med högre noggrannhet estimera mekaniska egenskaper i vävnad måste muskel anisotropi tas i hänsyn under MRE rekonstruktionen. Därav var syftet i denna uppsats att implementera en anisotropisk MRE rekonstruktion. Den implementerade anisotropa MRE rekonstruktionenlöser tre oberoende viskoelastiska parametrar (G||, G⊥, E||), som ärbaserad på en transversell isotropisk (TI) inversion. Rekonstruktionen validerades i en fantomstudie genom jämförelse med en isotropisk rekonstruktion samt in-vivo på gastrocnemius (ankel plantarflexion) och tibialis anterior (ankel dorsalflexion) hos en människa. Dessutom skapades en TI-fantom för att inkluderas i fantomstudien tillsammansmed en kommersiell isotropisk fantom. På grund av dålig bildkvalitet uteslöts TI-fantomen från ytterligare validering. Resultat från den isotropa fantomen överensstämde inte med antagandet om lika skjuvmodul i olika plan av det isotropa mediet. In vivo-studien visade att den anisotropa rekonstruktionen gav medelvärden för modulerna inom intervallet av vad litteraturen antyder. Olikheten av skjuvmodulen och elasticitetsmodulen för anisotropi i TI-material G||≠G⊥≠E|| observerades vilket är en indikation att rekonstruktionsmetoden kunde identifiera muskelvävnadens anisotropi. Det krävs dock ytterligare analys inklusive fler mänskliga försökspersoner för att dra slutsatsen ifall rekonstruktionsmetoden är tillförlitlig