The impact of osteoporosis on spinal biomechanical stability in adolescent idiopathic scoliosis: a narrative review of finite element analysis and bone mineral density assessment

Adolescent Idiopathic Scoliosis (AIS) is a complex three-dimensional spinal deformity whose precise etiology and pathological mechanisms remain incompletely understood. In recent years, increasing attention has focused on the association between the prevalent phenomenon of reduced bone mineral density (BMD) and osteoporosis in AIS patients and spinal biomechanical stability. This review aims to summarize the epidemiological characteristics and assessment methods of osteoporosis in AIS, with a primary focus on elucidating how it contributes to curve progression by influencing the spine’s mechanical properties. By integrating clinical BMD assessment data with analyses from patient-specific, image-based finite element models of the spine, this article systematically elaborates on the specific mechanisms by which osteoporosis affects the biomechanical stability of the AIS spine. These mechanisms encompass vertebral body strength, spinal flexibility, the risk of curve progression, and the outcomes of internal fixation surgery. This review provides novel perspectives and a theoretical foundation for a deeper understanding of AIS pathophysiology and for optimizing clinical assessment and developing individualized prevention and treatment strategies.