Discrepancies in anthropometric parameters between different models affect intervertebral rotations when loading...

Area of Science:

• Biomechanics
• Computational Modeling
• Spine Research

Background:

• Finite element (FE) simulations of the spine are limited, with few incorporating muscle forces.
• Previous studies transferred muscle forces from inverse static (IS) models to FE models but did not assess anthropometric sensitivities.

Purpose of the Study:

• To investigate the influence of anthropometric differences (body height, spinal orientation, body weight) between IS and FE models on intervertebral rotations (IVRs).
• To determine the sensitivity of FE models to variations in parameters transferred from IS models.

Main Methods:

• Muscle forces were calculated using an IS musculoskeletal model for 20° flexion and 10° extension.
• These forces were applied to a nonlinear FE model of the spino-pelvic complex.
• Anthropometric parameters (height ±10 cm, sagittal spinal orientation ±10°, weight ±10 kg) were varied between models to assess IVR changes.

Main Results:

• Deviations in body height, spinal orientation, and body weight caused maximum IVR changes of 19.2%, 26%, and 4.2%, respectively, relative to T12-S1.
• Spinal orientation and height showed the most significant impact on IVRs.

Conclusions:

• It is crucial for IS and FE models to share identical spinal orientation and height when transferring muscle forces.
• Consistent body weight between models is also important for accurate IVR predictions in spine simulations.