This research aims to enhance the control of intricate musculoskeletal spine models, a critical tool for comprehending both healthy and pathological spinal conditions. State-of-the-art musculoskeletal spine models incorporate segments for all vertebra, each possessing 3 degrees-of-freedom (DOF). Manually defining the posture with this amount of DOFs presents a significant challenge. The prevalent method of equally distributing the spine's overall rotation among the vertebrae often proves to be an inadequate assumption, particularly when dealing with the entire spine. We have engineered a comprehensive non-linear spine rhythm and the requisite tools for its implementation in widely utilized musculoskeletal modelling software (1). The rhythm controls lateral bending, axial rotation, and flexion/extension. The mathematical and implementation details of the rhythm are beyond this abstract, but it's noteworthy that the implementation accommodates non-linear rhythms. This means, for example, that one set of rhythm coefficients is used for flexion and another for extension. The rhythm coefficients, which distinguish the movement along the spine, were derived from a review of spine literature. The values for spine and vertebra range-of-motion (ROM) vary significantly in published studies, and no complete dataset was found in any single study. Consequently, the rhythm presented here is a composite, designed to provide the most consistent and average set of rhythm coefficients.Introduction
Method
Adolescent Idiopathic Scoliosis (AIS) is a three-dimensional deformity of the spine with unclear etiology. Due to the asymmetry of lateral curves, there are differences in the muscle activation between the convex and concave sides. This study utilized a comprehensive thoracic spine and ribcage musculoskeletal model to improve the biomechanical understanding of the development of AIS deformity and approach an explanation of the condition. In this study, we implemented a motion capture model using a generic rigid-body thoracic spine and ribcage model, which is kinematically determinate and controlled by spine posture obtained, for instance, from radiographs. This model is publicly accessible via a GitHub repository. We simulated gait and standing models of two AIS (averaging 15 years old, both with left lumbar curve and right thoracic curve averaging 25 degrees) and one control subject. The marker set included extra markers on the sternum and the thoracic and lumbar spine. The study was approved by the regional Research Ethics Committee (Journal number: H17034237).Introduction
Methods
