Reliability Modeling of Human Lumbar Functional Spinal Units System Degeneration

The degeneration of the human lumbar functional spinal units (FSUs) system is a great concern in healthcare. Existing statistical models fail to characterize the system's temporal changes under uncertainties mathematically. In this paper, we develop a stochastic model for the human lumbar FSUs system degeneration. We consider each component's degeneration mechanism, their spatial and mechanical interdependencies and the dependent competing failure, etc. to develop the overall system reliability function. Failure time distribution and remaining life prediction based on current states are proposed for practical application. In addition, we incorporate individual-specific characteristics into our model and propose varying parameters and failure thresholds for personalized accurate degeneration prediction. Actual time-series degeneration data are collected for model validation. The simulation and case studies show the accuracy of the proposed models. This work fills the gap in modeling and predicting a system degeneration in the human body and provides a framework for the degradation modeling of such complex systems in future research.