The immature spine: growth and idiopathic scoliosis

Untreated progressive scoliosis can have negative effects on the growing spine as asymmetrical forces will act on the growth plates of the vertebral column (>130 growth plates). Spinal growth can be considered as a mixture of hierarchy, synchronization, and harmony: the slightest error can lead to a complex malformation; it is also a very dynamic process although it does not progress linearly: periods of acceleration are followed by periods of deceleration. Remaining growth is a determining factor for the worsening of idiopathic scoliosis (IS): the younger is the child, the higher is the risk of progression, and the more severe will be the disease. After birth, growth of the spine is not linear, and three periods can be identified: (I) between birth and age 5 years; (II) between age 5 and 10 years of age; (III) between age 10 and skeletal maturity. Spine and thoracic cage growth are correlated, although their growth is not synchronous. Timely control of the spinal deformity and its correction are mandatory to restore—as soon as possible—the harmony and the hierarchy of growth between the different growth plates. If action is delayed, the abnormal growth and the subsequent anatomical modifications will lead to a progressive, evolutive, and irreversible clinical picture. This article aims to provide a comprehensive review of how spinal deformities can affect the normal spine and thoracic cage growth.