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Replicating Spine Behaviours in a Model

Replicating Spine Behaviours in a Model

According to the research presented in the PDF1, lifestyle heavily influences intervertebral disc (IVD) loads. Lifestyle factors such as daily activities, postures, and movements play a significant role in determining the loading experienced by the intervertebral discs. For example, activities like bending, twisting, lifting, and sitting for prolonged periods can subject the spine to varying degrees of loading, which can impact the health and function of the intervertebral discs.

The study emphasizes that measuring in vivo loads to understand the impact of lifestyle factors on intervertebral disc loading typically requires invasive methods, which may not be feasible or ethical for all populations. Therefore, developing non-invasive methods to estimate these loads and applying them in vitro can provide valuable insights into how lifestyle influences intervertebral disc biomechanics.

By simulating daily activities and applying physiological loads in vitro, researchers can better understand how different lifestyle factors affect intervertebral disc loading. This approach allows for the investigation of complex loading patterns experienced during functional and daily activities, providing a more comprehensive understanding of spine biomechanics and intervertebral disc mechanobiology.

In summary, lifestyle factors have a significant impact on intervertebral disc loads, and studying these influences through non-invasive estimation of in vivo loads and in vitro applications can enhance our knowledge of spine biomechanics and contribute to improving pre-clinical test methods for spinal health research.

How was the full-body Opensim model developed for this study?

The full-body OpenSim model for this study was developed by adapting and combining two existing models. The generic model was scaled using OpenSim’s Scaling Tool, which calculated the ratio of the distance between experimental and virtual marker pairs for each body segment. Motion capture and ground reaction force (GRF) data were used as inputs to calculate spinal loads. Muscle force estimates were evaluated using static optimization based on surface electromyography (sEMG) data. The model included bushing elements at all lumbar levels to represent passive joint stiffness, and a thoracic ball joint was added to simulate movements of the lumbar spine separately from the thoracic spine. This allowed for the replication of physiological ranges of motion in the lumbar region based on in vivo input data.

 

What are the limitations of measuring in vivo loads using invasive methods?

Measuring in vivo loads using invasive methods presents several limitations. One major limitation is the procedures’ invasiveness. These procedures often involve surgically implanting instrumentation or sensors into the spine to directly measure forces and moments experienced by the intervertebral discs. This invasive nature can pose ethical concerns and limit the feasibility of conducting such measurements on a wide range of populations, particularly healthy individuals.

Additionally, the use of invasive methods to measure spinal loads is typically restricted to patients who have undergone spinal fusion surgery. This limitation arises because instrumentation for measuring spinal loads is often implanted during surgical procedures, making it challenging to obtain in vivo load data from a diverse and representative population.

Furthermore, invasive methods for measuring spinal loads may not provide a comprehensive understanding of how lifestyle factors and daily activities influence intervertebral disc loading. The limited availability of in vivo load data obtained invasively restricts the ability to study the complex loading patterns experienced during various functional and daily activities.

In conclusion, the limitations of measuring in vivo loads using invasive methods include ethical concerns, restricted access to diverse populations, and a lack of comprehensive data on how lifestyle factors impact intervertebral disc loading. Developing non-invasive methods to estimate spinal loads and applying them in vitro can help overcome these limitations and provide valuable insights into spine biomechanics and intervertebral disc health.

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What are the conclusions of this study?

The study presented in the PDF “Replicating spine loading during functional and daily activities: An in vivo, in silico, in vitro research pipeline” concludes the following key points:

1. Successful Application of Complex Spinal Loads: The research successfully applied complex six-axis lumbar load profiles to bovine intervertebral discs (IVDs) in vitro using an innovative in vivo, in silico, in vitro research pipeline. This approach allowed for the replication of multi-axis loads during daily activities, demonstrating the feasibility of estimating spinal loading without invasive methods.

2. Comparison of Kinematics: By comparing the kinematics resulting from applying six-axis load profiles with simplified pure moment protocols commonly used in in vitro studies, the study revealed substantial differences in movement patterns. The physiological load profiles led to fundamentally different movement patterns, particularly in trunk flexion, highlighting the importance of replicating complex spinal loads for a more accurate biomechanical understanding.

3. Novel Capability for Spine Biomechanics Research: The study’s pipeline for estimating and replicating complex spinal loads provides a state-of-the-art research tool that can be effectively used to deepen our understanding of spine biomechanics and intervertebral disc mechanobiology. By employing non-invasive methods to estimate spinal load profiles, the research offers the potential to expand available load profiles to different population groups and enhance pre-clinical test methods for spinal health research.

4. Potential Applications: The study’s findings suggest that the developed pipeline can be applied to investigate how mechanical and biochemical environments interact in whole organ IVD culture models. Additionally, the estimated load profiles could be utilized to evaluate new treatments such as regenerative therapies or IVD replacements in vitro, contributing to advancements in spine biomechanics research and pre-clinical testing methods.

In summary, the study’s conclusions highlight the significance of replicating complex spinal loads during functional and daily activities using an innovative research pipeline. By combining in vivo, in silico, and in vitro methods, the study provides valuable insights into spine biomechanics, intervertebral disc health, and the development of novel research tools for studying spinal biomechanics in diverse populations.

 

At Dynamic Disc Designs we have worked to bring accurate modelling to the spine professional to aid in the teaching of conditions in a six degree format. Explore our growing line of realistic anatomical models.