Purpose
This study aimed to evaluate the predictive performance of preoperative computed tomography–based Hounsfield unit (HU) and magnetic resonance imaging-based vertebral bone quality score (VBQS) for cage subsidence after 1- to 2-level oblique lumbar interbody fusion (OLIF), and whether it differs by intraoperative cage placement position.
Methods
Ninety-one OLIF levels in 54 patients (2015–2022) were retrospectively reviewed in this single-center cohort. Subsidence was defined as ≥2 mm middle disc-height reduction or ≥2 mm cage protrusion at 1 year. Multivariable logistic regression with cluster-robust standard errors estimated adjusted odds ratios (OR); the pre-specified primary test was the lower-instrumented-vertebra HU×cage-position interaction.
Results
Subsidence occurred in 24 of 91 levels (26.4%). Each one-standard-deviation decrease in lower-instrumented-vertebra HU was independently associated with subsidence (adjusted OR, 0.40; 95% confidence interval, 0.20 to 0.81; p=0.011); VBQS was not. The subsidence group included more osteoporosis-range levels (<110 HU; 62.5% vs. 25.4%, p=0.003). The interaction was not significant (p=0.553), but the HU effect concentrated in middle-placed cages (adjusted OR, 0.345; p=0.012) and attenuated in anterior-placed cages (OR, 0.50; p=0.185).
Conclusion
Lower-instrumented-vertebra HU is an independent predictor of cage subsidence after 1- to 2-level OLIF, most evident in middle-placed cages.

Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity in adolescents, affecting individuals aged 10–16, with a multifactorial etiology involving genetic, hormonal, and biomechanical influences. This comprehensive literature review included 112 studies from journal conception to February 2025, retrieved from PubMed, Ovid MEDLINE, Scopus, and the Cochrane Library, focusing on epidemiology, pathophysiology, and treatment outcomes. AIS predominantly affects females, with a sex ratio increasing up to 7:1 in severe cases (>40° curves), and with right thoracic curves being the most common pattern. While bracing effectively prevents curve progression in moderate cases, spinal fusion remains the gold standard for severe deformities, ensuring long-term correction and preventing progression, despite a reduction in flexibility. Most adolescents return to full activities within a year postoperatively, with a low incidence of complications, including neurologic injury (~0.2%), infection (1%–5%), and pseudarthrosis (~1%). Future research will focus on optimizing non-fusion therapies, enhancing screening strategies, and integrating personalized medicine to improve patient outcomes and quality of life.