Introduction: This study presents a biomechanical model for bi-planar analysis (anterior-posterior, medial-lateral) of postural control in the time and frequency domains. This may be a useful tool to assess and gain insight into a basic functional ability. This model has been evaluated for characterizing balance strategies in adults, typical children, children with cerebral palsy, and most recently, adolescents with idiopathic scoliosis (AIS).
Objectives: The primary objective of this study was to determine if the biomechanical model was sufficiently sensitive to detect changes in postural control following surgical spinal fusion in subjects with AIS.
Materials and Methods: The biomechanical model was mathematically fit to experimental data acquired from fifteen AIS subjects before and after spinal fusion surgery. The model is simulated using MATLAB and SIMULINK and is fit to experimental data by systematically varying five parameters in each plane until the model's output and the experimental data are not statistically different. Values of the ten parameters that characterize the fitted model of balance were compared to determine sensitivity in the pre- and post-surgical results.
Results: The model was able to detect significant differences when comparing model parameter values before and after surgery. The model parameters that characterize stiffness in the anterior-posterior plane showed the greatest differences.
Conclusion: This model demonstrated sufficient sensitivity to detect statistically significant changes in postural control during quiet standing following spinal fusion.
Significance: Postural control is central to achieving maximum functional ability. This biomechanical model characterizes strategies used for balance and monitors changes resulting from surgical intervention.