28 research outputs found
A Robotic Neuro-Musculoskeletal Simulator for Spine Research
No full textAn influential conceptual framework advanced by Panjabi represents the living spine as a complex neuromusculoskeletal system whose biomechanical functioning is rather finely dependent upon the interactions among and between three principal subsystems: the passive musculoskeletal subsystem (osteoligamentous spine plus passive mechanical contributions of the muscles), the active musculoskeletal subsystem (muscles and tendons), and the neural and feedback subsystem (neural control centers and feedback elements such as mechanoreceptors located in the soft tissues) [1]. The interplay between subsystems readily encourages thought experiments of how pathologic changes in one subsystem might influence another--for example, prompting one to speculate how painful arthritic changes in the facet joints might affect the neuromuscular control of spinal movement. To answer clinical questions regarding the interplay between these subsystems the proper experimental tools and techniques are required. Traditional spine biomechanical experiments are able to provide comprehensive characterization of the structural properties of the osteoligamentous spine. However, these technologies do not incorporate a simulated neural feedback from neural elements, such as mechanoreceptors and nociceptors, into the control loop. Doing so enables the study of how this feedback--including pain-related--alters spinal loading and motion patterns. The first such development of this technology was successfully completed in this study and constitutes a Neuro-Musculoskeletal Simulator. A Neuro-Musculoskeletal Simulator has the potential to reduce the gap between bench and bedside by creating a new paradigm in estimating the outcome of spine pathologies or surgeries. The traditional paradigm is unable to estimate pain and is also unable to determine how the treatment, combined with the natural pain avoidance of the patient, would transfer the load to other structures and potentially increase the risk for other problems. The novel Neuro-Musculo
The Contribution of the Acetabular Labrum to Hip Joint Stability: A Quantitative Analysis Using a Dynamic Three-Dimensional Robot Model
No full textThe acetabular labrum provides mechanical stability to the hip joint in extreme positions where the femoral head is disposed to subluxation. We aimed to quantify the isolated labrum\u27s stabilizing value. Five human cadaveric hips were mounted to a robotic manipulator, and subluxation potential tests were run with and without labrum. Three-dimensional (3D) kinematic data were quantified using the stability index (Colbrunn et al., 2013, Impingement and Stability of Total Hip Arthroplasty Versus Femoral Head Resurfacing Using a Cadaveric Robotics Model, J. Orthop. Res., 31(7), pp. 1108-1115). Global and regional stability indices were significantly greater with labrum intact than after total labrectomy for both anterior and posterior provocative positions. In extreme positions, the labrum imparts significant overall mechanical resistance to hip subluxation. Regional stability contributions vary with joint orientation
A Comprehensive Specimen-Specific Multiscale Data Set for Anatomical and Mechanical Characterization of the Tibiofemoral Joint.
No full textUnderstanding of tibiofemoral joint mechanics at multiple spatial scales is essential for developing effective preventive measures and treatments for both pathology and injury management. Currently, there is a distinct lack of specimen-specific biomechanical data at multiple spatial scales, e.g., joint, tissue, and cell scales. Comprehensive multiscale data may improve the understanding of the relationship between biomechanical and anatomical markers across various scales. Furthermore, specimen-specific multiscale data for the tibiofemoral joint may assist development and validation of specimen-specific computational models that may be useful for more thorough analyses of the biomechanical behavior of the joint. This study describes an aggregation of procedures for acquisition of multiscale anatomical and biomechanical data for the tibiofemoral joint. Magnetic resonance imaging was used to acquire anatomical morphology at the joint scale. A robotic testing system was used to quantify joint level biomechanical response under various loading scenarios. Tissue level material properties were obtained from the same specimen for the femoral and tibial articular cartilage, medial and lateral menisci, anterior and posterior cruciate ligaments, and medial and lateral collateral ligaments. Histology data were also obtained for all tissue types to measure specimen-specific cell scale information, e.g., cellular distribution. This study is the first of its kind to establish a comprehensive multiscale data set for a musculoskeletal joint and the presented data collection approach can be used as a general template to guide acquisition of specimen-specific comprehensive multiscale data for musculoskeletal joints
Details of the locations and dimensions for all samples for mechanical tissue testing.
No full text<p>Diameter was assumed from punch diameter. Width was assumed from punch width, length was estimated from grip-to-grip distance at pre-load; and thickness was measured using a probe. ACL: anterior cruciate ligament; PCL; posterior cruciate ligament; MCL: medical collateral ligament; LCL: lateral collateral ligament.</p><p>Details of the locations and dimensions for all samples for mechanical tissue testing.</p
Evaluation of Patellofemoral Contact Mechanics as a Function of Quadriceps Load and Flexion Angle
No full textComparison of Different Posterior Instrumentation Systems in Achieving Stability to Supplement Transforaminal Lumbar Interbody Fusions (TLIFs): A Biomechanical Cadaver Study
No full textBiomechanical Analysis of Posterior Cruciate Ligament Reconstruction With Aperture Femoral Fixation
No full textOverview of multiscale data acquisition on the tibiofemoral joint.
No full text<p>Data collection includes magnetic resonance imaging (to reconstruct joint anatomy), joint mechanical testing (to interpret the mechanical behavior of the joint), tissue mechanical testing (to understand tissue material properties), and histology (to evaluate cell level and microstructural information).</p
Reconstructed stress-strain response of all tissues at target strain levels, for instantaneous and relaxed states.
No full text<p>Nominal stresses and grip-to-grip strains are reported. For estimates of moduli, refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138226#pone.0138226.t002" target="_blank">Table 2</a>. The posterior cruciate ligament failed during the second ramp loading (10% strain); this describes the unexpected decrease in the stiffness of this tissue for larger strains. At the relaxed state, the stress response of the menisci during compression was low; the values reported may potentially be hindered by experimentation capacity.</p
Stress-relaxation response of the anterior cruciate ligament.
No full text<p>Tensile stress data is shown along with the visualization of the sample at the beginning and end of the ramp and hold cycles.</p
