A SHIFTING FEMALE-TO-MALE RATIO OF INDIVIDUALS REQUIRING SURGERY FOR ADOLESCENT IDIOPATHIC SCOLIOSIS: A 15-YEAR EDIT PROSPECTIVE OBSERVATIONAL STUDY

Historically, the overall female-to-male ratio for adolescent idiopathic scoliosis(AIS) ranges between 1:1 and 3:1. Our experience suggests that the proportion of boys requiring AIS surgery is increasing, but there is no recent study supporting this clinical intuition. This study compares the preoperative characteristics and health-related quality of life scores between boys and girls scheduled for AIS surgery. A prospective observational cohort of 920 individuals scheduled for AIS surgery between years 2008-2022 was analyzed. Age, sex, female-to-male ratio, Risser sign, maximum Cobb angle and SRS-22r Patient Questionnaire were collected. Patients’ characteristics and health-related quality of life were compared between boys and girls using Mann-Whitney U tests for each year, and their relationship with year was assessed from Spearman correlations The overall female-to-male ratio for curves 10 degrees or more was between 2.0 and 3.0 between 2016-2022. For surgical patients, the mean ratio was 6.2 between 2008-2015 and 3.9 between 2016-2022, with a minimum of 2.9 and 2.8 in 2021 and 2022. The ratio decreased over the years (rho=-0.55, p=0.03). The number of boys requiring surgery increased (rho=0.69, p=0.004), while the number of girls remained constant over the years. Males tend to have improved SRS scores overall and prospective self-image increased for both males and females. In more recent years, males experience less pain and tend to experience better mental health in the pre-operative period. Current female-to-male ratios under 3:1 for individuals scheduled for AIS surgery is in sharp contrast with the literature. This is surprising considering that the overall ratio (for curves of any severity) remained constant over the years, in line with historical reports.