Introduction: This study investigated brace treatment for patients with adolescent idiopathic scoliosis (AIS) to comprehensively evaluate the factors associated with curve progression, including the effects of in-brace correction rate (ICR) and objective brace compliance. Additionally, it aimed to establish a clinically useful optimal ICR threshold for effective curve progression control.Methods: In this single-center retrospective analysis of prospectively collected data, 116 patients with AIS, with Cobb angles of 20°-40° and at least 1-year follow-up were included. Patients whose Cobb angles progressed by >5° were classified into the progressed group, whereas the others were categorized into the non-progressed group. Bracing time was objectively assessed using a thermometer.Results: In this study, 19 (16.4%) patients were assigned to the progressed group. Open triradiate cartilage was significantly more frequent in the progressed group (22.2% vs. 2.6%, p= 0.011) whereas no significant differences were observed in demographics or pre-brace Cobb angles. The progressed group demonstrated a lower ICR (26.8% vs. 39.5%, p= 0.002) and shorter bracing time at 6 months (14.0 hours vs. 17.4 hours, p= 0.042). Multivariate logistic regression analysis revealed that Sanders grade (1-4), ICR, and bracing time were independently associated with Cobb angle progression (odds ratios: 7.01, 0.95, and 0.89, respectively; all p< 0.05). Based on receiver operating characteristic curve analysis, the ICR threshold of 38.3% was identified to achieve a clinically significant negative predictive value of 95%.Conclusions:Under objective bracing time monitoring, skeletal maturity, ICR, and bracing time were crucial factors in preventing curve progression 1 year after brace initiation in patients with Cobb angles of 20°-40°. An ICR of 38.3% is recommended as the target when bracing adjustments are feasible.

Study Design: Multicenter retrospective cohort study. Purpose: To evaluate the impact of abscess presence and type on treatment duration and clinical outcomes in patients undergoing minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis. Overview of Literature: Surgical management is increasingly favored for pyogenic spondylitis. Abscesses, particularly epidural and iliopsoas, have been linked to poorer prognoses, and empyema, though uncommon, tends to be particularly severe. However, the effect of specific abscess types on surgical outcomes remains unclear. Methods: This study included 92 patients who underwent minimally invasive posterior fixation across 10 centers between 2014 and 2024. Patients were classified into an abscess group (epidural, iliopsoas, empyema, or other) and a non-abscess group. Clinical outcomes, including total duration of intravenous antibiotics and unplanned additional surgeries, were compared. Subgroup and regression analyses were conducted to assess the impact of specific abscess type. Results: Abscesses were present in 65 patients (71%): epidural (n=51), iliopsoas (n=38), and empyema (n=3), with some overlap. Compared with the non-abscess group (n=27; 29%), there were no significant differences in antibiotic duration or rates of unplanned additional surgery. However, iliopsoas abscess was associated with longer antibiotic duration (8.1 weeks vs. 6.6 weeks, p=0.044), while all empyema cases required additional surgery for poor infection control (p=0.000). Regression analysis identified iliopsoas abscess and age ≥65 years as independent predictors of prolonged antibiotic use, whereas epidural abscess was associated with shorter antibiotic duration. Conclusions: Iliopsoas abscesses were associated with longer antibiotic courses, while empyema was linked to poor infection control and a higher likelihood of additional surgery.