Dynamic morphometric characterization of local connective tissue network structure in humans using ultrasound

Background: In humans, connective tissue forms a complex, interconnected network throughout the body that may have mechanosensory, regulatory and signaling functions. Understanding these potentially important phenomena requires non-invasive measurements of collagen network structure that can be performed in live animals or humans. The goal of this study was to show that ultrasound can be used to quantify dynamic changes in local connective tissue structure in vivo. We first performed combined ultrasound and histology examinations of the same tissue in two subjects undergoing surgery: in one subject, we examined the relationship of ultrasound to histological images in three dimensions; in the other, we examined the effect of a localized tissue perturbation using a previously developed robotic acupuncture needling technique. In ten additional non-surgical subjects, we quantified changes in tissue spatial organization over time during needle rotation vs. no rotation using ultrasound and semi-variogram analyses. Results: 3-D renditions of ultrasound images showed longitudinal echogenic sheets that matched with collagenous sheets seen in histological preparations. Rank correlations between serial 2-D ultrasound and corresponding histology images resulted in high positive correlations for semi-variogram ranges computed parallel (r = 0.79, p < 0.001) and perpendicular (r = 0.63, p < 0.001) to the surface of the skin, indicating concordance in spatial structure between the two data sets. Needle rotation caused tissue displacement in the area surrounding the needle that was mapped spatially with ultrasound elastography and corresponded to collagen bundles winding around the needle on histological sections. In semi-variograms computed for each ultrasound frame, there was a greater change in the area under the semi-variogram curve across successive frames during needle rotation compared with no rotation. The direction of this change was heterogeneous across subjects. The frame-to-frame variability was 10-fold (p < 0.001) greater with rotation than with no rotation indicating changes in tissue structure during rotation. Conclusion: The combination of ultrasound and semi-variogram analyses allows quantitative assessment of dynamic changes in the structure of human connective tissue in vivo

Imaging Pain And Brain Plasticity: A Longitudinal Structural Imaging Study

Chronic musculoskeletal pain is a leading cause of disability worldwide yet the mechanisms of chronification and neural responses to effective treatment remain elusive. Non-invasive imaging techniques are useful for investigating brain alterations associated with health and disease. Thus the overall goal of this dissertation was to investigate the white (WM) and grey matter (GM) structural differences in patients with musculoskeletal pain before and after psychotherapeutic intervention: cognitive behavioral therapy (CBT). To aid in the interpretation of clinical findings, we used a novel porcine model of low back pain-like pathophysiology and developed a post-mortem, in situ, neuroimaging approach to facilitate translational investigation. The first objective of this dissertation (Chapter 2) was to identify structural brain alterations in chronic pain patients compared to healthy controls. To achieve this, we examined GM volume and diffusivity as well as WM metrics of complexity, density, and connectivity. Consistent with the literature, we observed robust differences in GM volume across a number of brain regions in chronic pain patients, however, findings of increased GM volume in several regions are in contrast to previous reports. We also identified WM changes, with pain patients exhibiting reduced WM density in tracts that project to descending pain modulatory regions as well as increased connectivity to default mode network structures, and bidirectional alterations in complexity. These findings may reflect network level dysfunction in patients with chronic pain. The second aim (Chapter 3) was to investigate reversibility or neuroplasticity of structural alterations in the chronic pain brain following CBT compared to an active control group. Longitudinal evaluation was carried out at baseline, following 11-week intervention, and a four-month follow-up. Similarly, we conducted structural brain assessments including GM morphometry and WM complexity and connectivity. We did not observe GM volumetric or WM connectivity changes, but we did discover differences in WM complexity after therapy and at follow-up visits. To facilitate mechanistic investigation of pain related brain changes, we used a novel porcine model of low back pain-like pathophysiology (Chapter 6). This model replicates hallmarks of chronic pain, such as soft tissue injury and movement alteration. We also developed a novel protocol to perform translational post-mortem, in situ, neuroimaging in our porcine model to reproduce WM and GM findings observed in humans, followed by a unique perfusion and immersion fixation protocol to enable histological assessment (Chapter 4). In conclusion, our clinical data suggest robust structural brain alterations in patients with chronic pain as compared to healthy individuals and in response to therapeutic intervention. However, the mechanism of these brain changes remains unknown. Therefore, we propose to use a porcine model of musculoskeletal pain with a novel neuroimaging protocol to promote mechanistic investigation and expand our interpretation of clinical findings

Electrical Impedance of Acupuncture Meridians: The Relevance of Subcutaneous Collagenous Bands

Background: The scientific basis for acupuncture meridians is unknown. Past studies have suggested that acupuncture meridians are physiologically characterized by low electrical impedance and anatomically associated with connective tissue planes. We are interested in seeing whether acupuncture meridians are associated with lower electrical impedance and whether ultrasound-derived measures – specifically echogenic collagenous bands- can account for these impedance differences. Methods/Results: In 28 healthy subjects, we assessed electrical impedance of skin and underlying subcutaneous connective tissue using a four needle-electrode approach. The impedances were obtained at 10 kHz and 100 kHz frequencies and at three body sites- upper arm (Large Intestine meridian), thigh (Liver), and lower leg (Bladder). Meridian locations were determined by acupuncturists. Ultrasound images were obtained to characterize the anatomical features at each measured site. We found significantly reduced electrical impedance at the Large Intestine meridian compared to adjacent control for both frequencies. No significant decrease in impedance was found at the Liver or Bladder meridian. Greater subcutaneous echogenic densities were significantly associated with reduced impedances in both within-site (meridian vs. adjacent control) and between-site (arm vs. thigh vs. lower leg) analyses. This relationship remained significant in multivariabl

Coronectomy of deeply impacted lower third molar : incidence of outcomes and complications after one year follow-up

Objectives: The purpose of present study was to assess the surgical management of impacted third molar with proximity to the inferior alveolar nerve and complications associated with coronectomy in a series of patients undergoing third molar surgery. Material and Methods: The position of the mandibular canal in relation to the mandibular third molar region and mandibular foramen in the front part of the mandible (i.e., third molar in close proximity to the inferior alveolar nerve [IAN] or not) was identified on panoramic radiographs of patients scheduled for third molar extraction. Results: Close proximity to the IAN was observed in 64 patients (35 females, 29 males) with an impacted mandibular third molar. Coronectomy was performed in these patients. The most common complication was tooth migration away from the mandibular canal (n = 14), followed by root exposure (n = 5). Re-operation to remove the root was performed in cases with periapical infection and root exposure. Conclusions: The results indicate that coronectomy can be considered a reasonable and safe treatment alternative for patients who demonstrate elevated risk for injury to the inferior alveolar nerve with removal of the third molars. Coronectomy did not increase the incidence of damage to the inferior alveolar nerve and would be safer than complete extraction in situations in which the root of the mandibular third molar overlaps or is in close proximity to the mandibular canal

Second International Fascia Research Congress

n/

Trabecular Calcium Phosphate Scaffolds for Bone Regeneration

Bone tissue engineering represents a strategy for the repair or regeneration of damaged bone in the body. The science underlying this clinical therapy bridges the traditional fields of cell biology, materials science and mechanical engineering with the aim to identify how cells behave on physiologically relevant materials with natural mechanical stimuli. The objectives of this research were to develop and characterize calcium phosphate ceramic scaffolds matched to the local architecture of natural trabecular bone and to apply tissue engineering strategies for the study of cell behavior in both in vitro and in vivo models.The specific role of environment on cell stress pathways was evaluated on three dimensional (3-D) calcium phosphate scaffolds resembling vertebral trabecular bone. A scaffold foam dipping technique was employed in the fabrication of fully sintered hydroxyapatite and tricalcium phosphate scaffolds. Study of the early cell behavior on two dimension (2-D) controls and scaffolds was performed using human embryonic palatal mesenchyme cells (HEPM), an osteoblast precursor cell line. Cell stress signaling was identified in response to the 3-D architecture using; members of the mitogen activated protein kinase cascade, cell survival signals and adhesion dependant proteins. The application of low intensity pulsed ultrasound (LIPUS) or fluid perfusion further stimulated cell-scaffold hybrids for short and long term in vitro study. Additionally, an animal model was characterized using the scaffolds for the repair of a segmental defect in the canine mandible.Study of the cell stress signaling mechanisms identified high activation of stress pathways on 3-D materials compared to controls with a corresponding increase in anti- apoptosis signaling. Similar trends were found with LIPUS stimulation demonstrating that changes in adhesion proteins during attachment may account for the alteration in stress pathways activated by bone precursors. The absence of cell death and the activation of an anti-apoptosis signal suggest that cells are able to manage these stress levels which may be required for proper function. Supporting this theory, long term in vitro perfusion studies demonstrated that the process of cell transition into a mature bone phenotype was improved with the fluid shear forces of perfusion. Finally, the scaffolds were applied for repair of a segmental defect in the canine mandible and demonstrated extensive bone in-growth and partially-organized, lamellar collagen fiber assembly characteristic of organized bone. The open architecture of the scaffold design also allowed for substantial blood vessel infiltration.This research demonstrated the importance of architecture on bone cell response for in vitro cell study and for clinical application. The scaffold design provides a bridge between laboratory based signaling mechanisms and the development of clinical therapies in regenerative orthopedics

Ultrasound assessment of deep fascia sliding mobility in vivo: a scoping review

Introdução: A falha do deslizamento fascial pode ocorrer em casos de uso excessivo ou inadequado, trauma ou cirurgia, resultando em inflamação local, dor, sensibilização e potencial disfunção. As propriedades mecânicas dos tecidos fasciais, incluindo a sua mobilidade, têm sido avaliadas in vivo através de ecografia. No entanto, este parece ser um método que ainda não está devidamente padronizado nem validado. Objetivos: Identificar, sintetizar e comparar os princípios metodológicos da investigação científica que utilizou a avaliação ecográfica do deslizamento da fáscia profunda em humanos in vivo, e avaliar a sua fiabilidade. Métodos: Realizou-se uma pesquisa sistemática da literatura nas bases de dados ScienceDirect, PubMed (Medline), Web of Science e B-On, de acordo com as diretrizes PRISMA Extension for Scoping Reviews (PRISMA-ScR). A revisão seguiu três etapas principais: (1) identificação da questão e da literatura relevante; (2) seleção da literatura; e (3) agrupamento, mapeamento e resumo dos dados. Critérios de elegibilidade: Foram incluídos os artigos que usaram a ecografia para avaliar o deslizamento da fáscia profunda em seres humanos in vivo, usando o termo “sliding” ou outro com significado semelhante. Foram excluídos os estudos: não disponíveis em publicações revistas por partes, não disponíveis em inglês, português ou espanhol ou cujo texto completo não se encontrava acessível. Resultados: De um total de 104 artigos completos avaliados para elegibilidade, foram incluídos 18 artigos que avaliaram as fáscias profundas das regiões toracolombar (n=4), abdominal (n=7), femoral (n=4) e crural (n=3). Estes estudos abordaram questões de diagnóstico (n=11) e benefícios terapêuticos (n=7) e apresentaram níveis de evidência entre II e IV. Foram usados vários termos para descrever as medidas de resultados correspondentes ao deslizamento fascial. Foram usados diversos posicionamentos dos participantes, procedimentos para induzir o deslizamento fascial e características dos dispositivos de ecografia. Os métodos de análise do deslizamento fascial incluíram a comparação de imagens ecográficas inicial (estado de repouso) e final (estado alvo) e o uso de técnicas de software de correlação-cruzada através de algoritmos de rastreamento automatizado. Estes métodos mostraram-se fiáveis para medir o deslizamento entre a fáscia toracolombar, as junções músculo-fasciais do transverso abdominal, a fáscia lata e a fáscia crural e as fáscias epimisiais adjacentes. No entanto, os artigos incluídos apresentaram terminologias, questões de investigação, populações participantes e metodologias heterogéneas. É escassa a investigação de alta qualidade para determinar a fiabilidade dos métodos atuais para analisar outras fáscias e avaliar a influência da idade, de características relacionadas com o género, composição corporal ou condições clínicas específicas nas medidas de deslizamento fascial. Conclusão: Os métodos ecográficos de medição do deslizamento fascial incluem a comparação entre frames inicial e final de uma gravação de vídeo de ultrassom e a análise de relação cruzada através de algoritmos de rastreamento automatizado. Estes métodos parecem ser fiáveis para medir o deslizamento de algumas fáscias, mas é necessária literatura para confirmar a sua fiabilidade para outras. Além disso, são necessários protocolos de avaliação específicos e padronizados para cada região anatómica, de modo que a avaliação ecográfica do deslizamento fascial in vivo possa ser usada adequadamente na investigação e na prática clínica

Vulnerability of the superficial zone of immature articular cartilage to compressive injury

Objective The zonal composition and functioning of adult articular cartilage causes depth-dependent responses to compressive injury. In immature cartilage, shear and compressive moduli as well as collagen and sulfated glycosaminoglycan (sGAG) content also vary with depth. However, there is little understanding of the depth-dependent damage caused by injury. Since injury to immature knee joints most often causes articular cartilage lesions, this study was undertaken to characterize the zonal dependence of biomechanical, biochemical, and matrix-associated changes caused by compressive injury. Methods Disks from the superficial and deeper zones of bovine calves were biomechanically characterized. Injury to the disks was achieved by applying a final strain of 50% compression at 100%/second, followed by biomechanical recharacterization. Tissue compaction upon injury as well as sGAG density, sGAG loss, and biosynthesis were measured. Collagen fiber orientation and matrix damage were assessed using histology, diffraction-enhanced x-ray imaging, and texture analysis. Results Injured superficial zone disks showed surface disruption, tissue compaction by 20.3 ± 4.3% (mean ± SEM), and immediate biomechanical impairment that was revealed by a mean ± SEM decrease in dynamic stiffness to 7.1 ± 3.3% of the value before injury and equilibrium moduli that were below the level of detection. Tissue areas that appeared intact on histology showed clear textural alterations. Injured deeper zone disks showed collagen crimping but remained undamaged and biomechanically intact. Superficial zone disks did not lose sGAG immediately after injury, but lost 17.8 ± 1.4% of sGAG after 48 hours; deeper zone disks lost only 2.8 ± 0.3% of sGAG content. Biomechanical impairment was associated primarily with structural damage. Conclusion The soft superficial zone of immature cartilage is vulnerable to compressive injury, causing superficial matrix disruption, extensive compaction, and textural alteration, which results in immediate loss of biomechanical function. In conjunction with delayed superficial sGAG loss, these changes may predispose the articular surface to further softening and tissue damage, thus increasing the risk of development of secondary osteoarthritis.National Institutes of Health (U.S.) (grant P5O-AR39239)National Institutes of Health (U.S.) (grant R01-AR45779)Deutsche Forschungsgemeinschaft (DFG) (grant RO 2511/1-1)Deutsche Forschungsgemeinschaft (DFG) (grant RO 2511/2-1