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.

Background
Lumbar Arthroscopic Spinal Surgery (LASS) has several advantages compared to conventional procedures in terms of improved visual field, versatility with instrumentation, and ease of handling.
Purpose
To report the learning curve of LASS for more than 10 years by an experienced spine surgeon.
Materials and Methods
We retrospectively reviewed medical records of the patients who underwent LASS from Dec. 29th, 2017 to April 31st, 2018. Lumbar Arthroscopic Discectomy (LADi), Lumbar Arthroscopic Decompression (LAD), Lumbar Arthroscopic Foraminoplasty (LAF) were performed. Operation time, the amount of bleeding, the length of hospital stay and the degree of postoperative pain were analyzed to evaluate the learning curve.
Results
28 cases (90.3%) showed satisfactory postoperative results. The operation time per segment was 124.2±58.5 minutes (range 45~247). The mean operation time for LADi was 91.4±62.7 minutes (45~247), for LAD was 136.1±53.8 minutes (68~222 minutes) and for LAF was 135.3±50.6 minutes (72~245), and was indicating a declining trend. In the LAF, the slope of the decline of the learning curve was gentle compared to other operations.
Conclusion
The results of short-term follow-up of LASS are excellent, and it is easy to acquire skills in experienced spine surgeon.