Impact of scoliosis screening on surgical threshold attainment: a 30-year population-based longitudinal cohort study.

BACKGROUND

The United States Preventive Services Task Force cites insufficient evidence that treating screen-detected AIS improves long-term health outcomes, questioning the value of screening.

PURPOSE: To assess the association between a 30-year sustained territory-wide scoliosis screening program and long-term trends in surgical threshold attainment for AIS following the Scoliosis Research Society's criteria.

STUDY DESIGN/

SETTING

Population-based longitudinal cohort study PATIENT SAMPLE: We included adolescents aged 10-19 years with AIS and Cobb angle ≥ 20° between 1995 and 2024 from the two tertiary referral scoliosis clinics.

OUTCOME MEASURES: Trends in surgical threshold attainment for AIS.

METHODS

Age-period-cohort (APC) analysis assessed temporal trends associated with the screening program, with Kaplan-Meier and adjusted Cox modelling as sensitivity analyses.

RESULTS

With an overall screening rate of 90.3%, representing 30,818 adolescents, 26,232 (76.9%) females were identified; 2,563 reached surgical threshold (2,011 [78.5%] females). APC analyses showed a pronounced decline in surgical threshold attainment (RR: 1.00 to 0.18) with significant period and cohort effects (p<0.001). Kaplan-Meier and Cox analyses demonstrated improved surgical threshold-free survival (χ² = 93.8, p<0.001) and lower hazards of surgical threshold attainment associated with screening (HR: 0.29; 95% CI, 0.27- 0.32; p<0.001). Concurrently, AIS prevalence with Cobb angle ≥ 20° increased from 0.02% (95% CI, 0.01% - 0.02%) in 1995 to 1.59% (95% CI, 1.56% - 1.62%) in 2019.

CONCLUSIONS

This 30-year population-based study provides evidence that screening, by enabling earlier detection, is associated with substantial and sustained decline in surgical threshold attainment. This decline was likely multifactorial, reflecting concurrent advances in conservative management and clinical care. These findings provide important longitudinal evidence to inform scoliosis screening recommendations.