Etiology and natural history of adolescent idiopathic scoliosis: A review

Abstract

Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity with a prevalence of 1.34%, although the percentage of population requiring treatment is substantially less. Understanding the etiopathogenesis and natural history of a disorder is most important to formulate effective treatment strategies. For the past few decades, researchers have probed the etiopathogenesis of AIS from various angles of genetic, neurological dysfunction, biomechanical, hormonal, and developmental disturbances. Various theories have been put forward based on association studies that found no correlation. However, direct cause–effect relationship has not been established for any individual factor till now. Also whether these findings are either primarily the cause for scoliosis or secondary to AIS remains unknown. From the existing literature, AIS appears to be a multifactorial disorder with a strong genetic predisposition, hormonal and environmental disturbances. Literature on the natural history of AIS is limited with only few studies that have long-term follow-ups on untreated scoliosis. On the basis of the available literature, it can be safely said that AIS has a benign course with very minimal or no functional disability in the long-term follow-up. The minimal risk of mortality is present only in curves of more than 100° with severe pulmonary dysfunction and cor pulmonale. Here we review the important theories, hypothesis, and recent trends in research on etiopathogenesis of AIS and also summarize on the natural history of the disorder.