Adolescent idiopathic scoliosis refers to spinal deformity that develops from just before the onset of puberty until the completion of skeletal growth, and the primary goal of treatment is to achieve a well-balanced spine. In the late 1990s, advances in the anatomical understanding of the spine and the development of fixation instruments made posterior pedicle screw insertion feasible, thereby enabling the transmission of powerful corrective forces for deformity correction. Over the subsequent decades, accumulated clinical experience and outcomes have provided a deeper understanding of scoliotic curves and led to the establishment of effective principles for determining the extent of spinal fusion. However, these treatment principles are based on the unique biomechanics and procedural characteristics of scoliosis correction surgery, which can make them difficult to understand without sufficient explanation. In this review, we aim to describe these established treatment principles and surgical processes in detail using schematic illustrations and images. Although these principles will continue to undergo new challenges and validation over time, they will remain a meaningful reference point for those exploring alternative strategies.