Spinopelvic alignment in asymptomatic adults: a global meta-analysis quantifying heterogeneity and proposing a functional parameter hierarchy

We propose a functional hierarchy of spinopelvic parameters based on their observed heterogeneity-from stable "core" to variable "adaptive" components. Future research is warranted to validate the potential population-invariance of currently underreported bicoxofemoral axis-referenced parameters and to evaluate whether correction strategies focused on these stable elements improve surgical outcomes.