Purpose
This study aims to identify risk factors and changes in spino-pelvic parameters associated with Sacroiliac (SI) joint degeneration.
Materials and Methods
This multicenter retrospective study included 472 patients who underwent fusion surgery at three hospitals between March 2021 and February 2024. SI joint degeneration was assessed using seven indicators: sclerotic changes, erosion, osteophyte formation, intra-articular bone formation, joint space narrowing, intra-articular gas formation, and subchondral cysts. CT scans were performed preoperatively and 6 months postoperatively. The patients were divided into two groups: those with progression of SI joint degeneration and those without. Standing whole spine lateral X-rays were used to measure a total of 10 spinopelvic parameters both preoperatively and at 6 months postoperatively. Statistical analysis was performed using two-sample t-tests and multivariable logistic regression.
Results
Among the 472 patients, 135 (28.6%) showed progression of SI joint degeneration. When comparing the two groups, age (p=0.022), alcohol consumption (p=0.001), smoking (p<0.001), and S1 involvement (p=.04) were associated with SI joint degeneration. Regarding spino-pelvic parameters, patients with SI joint degeneration exhibited significant changes in thoracic kyphosis (p=0.017) and pelvic tilt (p=0.049).
Conclusions
Sacrum fixation, smoking, alcohol consumption, and age can be significant risk factors for SIJ degeneration following lumbar fusion surgery.

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.