215 research outputs found

    MRI Evaluation of Finger Flexor Trajectories as They Enter, Pass Through and Exit the Carpal Tunnel as a Function of Forearm Rotation and Wrist Radial and Ulnar Deviation

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    Tendon displacement within the carpal tunnel has been suggested as a mechanism for wrist work-related musculoskeletal disorders. Tendon displacement has been examined during wrist flexion/extension, and forearm pronation/supination. The effects of radial/ulnar deviation, and how they interact with forearm rotation remain undocumented. The purpose of this study was to quantify linear and angular displacement of the finger flexor tendons during wrist radial/ulnar deviation in combination with forearm pronation/supination. The right distal forearms and wrists of 4 participants were scanned using magnetic resonance imaging. Analysis of the images enabled the measurement of linear and angular displacement. Tendons were displaced radially during radial deviation and pronation, and ulnarly during ulnar deviation and supination. The tendons were displaced furthest during radial-pronation and ulnar-supination. These findings support the results of previous researchers who found increased discomfort and median nerve contact pressure in these postures. These data further our understanding of potential mechanisms of injury

    Comparative study between physical examination, electroneuromyography and ultrasonography in diagnosing carpal tunnel syndrome

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    AbstractObjectiveTo evaluate the sensitivity of electromyography and ultrasonography in diagnosing carpal tunnel syndrome (CTS), in comparison with physical examination, which is considered to be the gold standard.MethodsIn this cross-sectional study, the medical files of 56 patients with 70 hands affected by CTS who were attended between March 2010 and June 2012 were reviewed. The study included patients with a clinical diagnosis of CTS. The sensitivity of the complementary examinations was analyzed and compared with physical examination.ResultsNocturnal symptoms were found in 96.4%, thenar atrophy in 62.5% and abnormal sense of touch in 50%. The sensitivities found were: ultrasonography, 67.1% (95% CI: 55.7%–78.6%); an association of physical examination tests, 95.7% (95% CI: 90.0%–100%); and electromyography, 98.6% (95% CI: 95.7%–100%). The presence of atrophy, abnormalities of the sense of touch and longer-duration symptoms increased the sensitivity of ultrasonography and physical examination.ConclusionThe sensitivity of ultrasonography for CTS was lower than that of electromyography and physical examination

    3D computerized model for measuring strain and displacement of the brachial plexus following placement of reverse shoulder prosthesis

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    The aim of the present study was to develop a method for three-dimensional (3D) reconstruction of the brachial plexus to study its morphology and to calculate strain and displacement in relation to changed nerve position. The brachial plexus was finely dissected and injected with contrast medium and leaden markers were implanted into the nerves at predefined places. A reverse shoulder prosthesis was inserted in a cadaveric specimen what induced positional change in the upper limb nerves. Computed tomography (CT) was performed before and after this surgical intervention. The computer assisted image processing package Mimics (R) was used to reconstruct the pre- and postoperative brachial plexus in 3D. The results show that the current interactive model is a realistic and detailed representation of the specimen used, which allows 3D study of the brachial plexus in different configurations. The model estimated strains up to 15.3% and 19.3% for the lateral and the medial root of the median nerve as a consequence of placing a reverse shoulder prosthesis. Furthermore, the model succeeded in calculating the displacement of the brachial plexus by tracking each implanted lead marker. The presented brachial plexus 3D model currently can be used in vitro for cadaver biomechanical analyses of nerve movement to improve diagnosis and treatment of peripheral neuropathies. The model can also be applied to study the exact location of the plexus in unusual upper limb positions like during axillary radiation therapy and it is a potential tool to optimize the approaches of brachial plexus anesthetic blocks

    Effects of Surgical Repair or Reconstruction on Radiocarpal Mechanics from Wrists with Scapholunate Ligament Injury

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    Osteoarthritis as a result of injury/trauma is a significant problem, and there is still a need to develop tools for evaluating joint injuries and the effectiveness of surgical treatments. For the wrist in particular, injury to the scapholunate ligament from impact loading, can lead to scapholunate joint instability. Without treatment, this can lead to progressive development of wrist osteoarthritis. Joint contact pressures are important mechanical factors in the etiology of osteoarthritis, and these can be determined non-invasively through computer modeling. Hence, the goal of this work was to investigate the effects of scapholunate ligament injury and surgical repair on radioscapholunate contact mechanics, through surface contact modeling (SCM) and finite element modeling (FEM). The modeling process required geometries, boundary conditions and a contact relationship. Magnetic resonance imaging (MRI) was used to acquire images of the normal, injured and post-operative wrists, while relaxed and during active grasp loading. Surface and volumetric models were generated from the relaxed images, while kinematic boundary conditions were determined from image registration between the relaxed and loaded images. To improve the automatic image registration process, the effects of initial manual registration on the outcome of final registration accuracy, were investigated. Results showed that kinematic accuracy and subsequent contact mechanics were improved by performing a manual registration to align the image volumes as close as possible, before auto-registration. Looking at the effects of scapholunate ligament injury, results showed that contact forces, contact areas, peak and mean contact pressures significantly increased in the radioscaphoid joint. The locations of contact also shifted with injury. This novel data showed that contact mechanics was altered for the worse after injury. Novel contact mechanics data on the effects of surgical repair were also obtained. Results showed that radiolunate peak and mean contact pressures decreased significantly compared to injured, which indicated the possibility of restoring normal mechanics post surgery. SCM results were compared to FEM results to demonstrate the feasibility of the surface contact modeling approach for clinical applications. Contact parameters compared well between the two techniques. This work demonstrated the potential of MRI-based SCM as a tool to evaluate joint injuries and subsequent treatments, for clinical applications

    Old name, new face: a systematic analysis of flexor digitorum superficialis muscle with "chiasma antebrachii"

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    he gross anatomy of the forearm flexors, particularly that of the flexor digitorum superficialis (FDS) muscle, has been described and graphically illustrated in several anatomical books and atlases starting in the middle of the century before last. However, in anatomical dissection studies as well as in clinical-anatomical courses training muscle-specific targeted injections due to movement disorders such as dystonia or spasticity, it has become apparent that there is a need for a closer investigation of the complex construction of the FDS muscle. To this end, we studied the structure of the muscle bellies and tendons of FDS on 46 human body donates that have been used either in our dissection or clinical-anatomical training courses. With this, we demonstrate here the topographical configuration of the individual muscle belly for each of digits 2 through 5 and the exact paths of their tendons until their passing through the carpal tunnel. Furthermore, we demonstrate the presence of a chiasm of the FDS tendons for the digits 2 and 3, approximately 3-4 cm proximal of the carpal tunnel. Thus, we introduce herewith the terminology “chiasma antebrachii”. These findings were confirmed in situ by imaging of fixed human body donates via MRI and corroborated by MRI and ultrasound imaging in two volunteers. Taken together, the present findings enable an updated understanding of the complex organization of the heads, bellies, and tendons of FDS that is relevant not only for anatomical teaching but also clinical interventions

    Imaging biomarkers as outcome measures for hereditary and acquired neuromuscular diseases

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    The generic term biomarkers applies to all detection methods used in the life sciences and may be defined as any detectable biologic parameter, whether biochemical, genetic, histologic, anatomic, physical, functional, or metabolic. By logical extension, we define imaging biomarkers as any anatomic, physiologic, biochemical, or molecular parameter detectable with one or more diagnostic imaging tools for establishing the presence and/or severity of disease. The importance of medical imaging for clinical decision making has been steadily increasing over the last four decades. Recently, there has also been an emphasis on medical imaging for preclinical decision making, i.e., for use in pharamaceutical and medical device development. There is also a drive towards quantification of imaging findings by using quantitative imaging biomarkers, which can improve sensitivity, specificity, accuracy and reproducibility of imaged characteristics used for diagnostic and therapeutic decisions. During the three-years Phd project, in collaboration with the Radiology Department of Poliliclinico San Martino/ Dipartimento di Scienze della Salute, the Neurology Unit of Policlinico San Martino / Dipartimento di Scienza della Salute and the Anatomy Departement of University of Barcelona/Campus Bellvitge, the clinical applications of new or recently developed imaging biomarkers based on High Resolution Ultrasound (HRUS) a Magnetic Resonance (MR) in the field of neuromuscular diseases have been indagated. The recent advancements in Ultrasound technology enabled a high resolution and Ultra-High resolution imaging of peripheral nerves. In this regard, the fascicular imaging application in the diagnosis of posterior interosseous nerve and the motor branch of median nerve have been subject of two clinical study. The availability of a 7 tesla MR in the Animal facility of Policlinico San Martino allowed an high-tech study on a murin model of Charcot-Marie-Tooth neuropathy 1B, providing new insight into the pathogenesis of this condition. Regarding the myopathies, a specific focus was sarcopenia and the Ultrasound-derived quantitative and semiquantitative parameters to identify this common condition, to stratify the disease severity and to facilitate the patient monitoring overtime

    Finger Flexor Tendon Orientation and Location as a Function of Postural Changes of the Wrist and Forearm: The Quantification of Musculoskeletal Loading in Jobs with Deviated Forearms

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    Forearm pronation/supination is common during manual activities, and has been linked to upper limb disorders in the workplace (Hughes et al. 1997). Forearm deviations from neutral (palm of the hand facing medially) can increase discomfort and forearm musculature activity (EMG) (Khan 2009a; Domizio & Keir, 2010), particularly when combined with wrist postures deviated from neutral. Yet ergonomic tools commonly used to assess the risk of developing distal upper limb disorders (e.g., Strain Index and RULA), often disregard or only minimally account for forearm pronation/supination posture. As a result, the risk of injury may be underestimated. This dissertation first examined methods of measuring pronation in the workplace by testing instantaneous agreement of forearm posture measurements between Inertial Motion Units (Xsens, Netherlands) and a laboratory-based motion capture system (Vicon, UK). Participants turned metallic and non-metallic handles in front of them, in order to quantify the effect of magnetic disturbance and sensor orientation on the Xsens. On average, RMSE errors of 12.6 deg around metal, and 8.6 deg around plastic were observed on instantaneous measures. Higher rotational velocities appeared associated with larger errors. Summarized data revealed smaller discrepancies. Second, this dissertation examined the effect of forearm pronation/supination coupled with wrist flexion/extension on the orientation and location of finger flexor tendons with respect to a radial coordinate system, using MRI of 4 healthy wrists. Pronation/supination caused movement almost exclusively in the frontal plane. Radial tendons exhibited larger angular deviations in pronation, whereas ulnar tendons were nearly straight, and the opposite was observed in supination. Larger angular deviations were thought to increase contact forces within the tunnel in the direction of the bend, which combined with finger movement could increase the risk of tenosynovitis. Finally the results of these studies were combined to measure tendon movement during a repetitive task. The three tendons with the greatest angular movement in the tunnel were: FDP2 (0.16 deg/pronation/supination degree), FDS3 (0.15 deg/ pronation/supination degree), and FDS4 (0.17 deg/ pronation/supination degree)

    Computer-aided techniques for assessment of MRI-detected inflammation for early identification of inflammatory arthritis

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    Inflammatory arthritis comprises a group of diseases in which the immune system attacks the body’s own tissues. Two prevalent types of inflammatory arthritis are rheumatoid arthritis (RA) and spondyloarthritis (SpA). Clinical research points to the importance of early diagnosis, as treatment in early disease stages increases chances of better outcome and improved quality of life for patients. To this end, the diagnostic potential of imaging modalities sensitive to local inflammation, such as magnetic resonance imaging (MRI), is of great interest. The goal of this thesis was to develop computer-aided methods for assessment of MRI-detected inflammation with the aim of aiding early diagnosis of inflammatory arthritis. In particular, we focused on the tasks of comparative visualization, automatic quantification, and feature selection. The presented studies showcase the potential of comparative visualization and automatic quantification to overcome the limitations of visual scoring and lay out a fertile ground for future improvements. Additionally, the understanding of the diagnostic role of individual inflammatory features in prediction of RA development is further advanced. Collectively, these findings can help facilitate the use of MRI for early diagnosis of inflammatory arthritis and potentially increase chances of better outcome and quality of life for patients.This research was supported by the Dutch Technology Foundation STW, under grant number 13329. STW (currently TTW) is part of the Netherlands Organization for Scientific Research (NWO), which is partly funded by the Dutch Ministry of Economic Affairs.LUMC / Geneeskunde Repositoriu
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