Sensitivity Analysis of a Morphological Finite Element L4-L5 Functional Spine Unit for Biomechanical Responses.

Area of Science:

• Biomechanics
• Spinal Anatomy
• Computational Modeling

Background:

• Static vertebral models lack predictive power for personalized medicine and injury prevention.
• In vitro experiments face limitations due to minimal shape variation in study populations.

Purpose of the Study:

• To assess the sensitivity of anthropometric features on the biomechanical responses of the L4-L5 lumbar functional spine unit (FSU).
• To identify key morphological parameters influencing FSU biomechanics under moment loading.

Main Methods:

• Generated a population of L4-L5 FSUs using Design of Experiments (DoE) framework with OFAT and CLHS sampling.
• Applied anthropometric variations (disc wedging, diameters, vertebral height, facet angle) using ANSA BETA CAE TM.
• Performed sensitivity analysis using Pearson's Correlation Coefficient and linear regression.

Main Results:

• Transverse diameter and anteroposterior diameter showed strong negative correlations with Range of Motion (ROM).
• Disc wedging angle exhibited a strong positive correlation with facet contact force.
• Identified key anthropometric parameters influencing biomechanical responses like ROM, disc pressures, and facet contact forces.

Conclusions:

• Morphological variations significantly influence lumbar functional spine unit biomechanics.
• Transverse diameter, anteroposterior diameter, and disc wedging angle are critical predictors of biomechanical responses.
• Findings align with existing in vitro data, supporting the utility of morphological models for spine research.