Posterior spinal fusion outcomes for moderate adolescent idiopathic scoliosis in boys and girls: should we counsel them the same?

Purpose: With this study, we aim to evaluate and compare the perioperative outcomes of PSF for girls and boys. We hypothesize that female patients will have better curve correction and lower rates of complications when compared to male patients. Methods: This study employed a retrospective review of AIS patients who underwent PSF at 23 sites between 2011 and 2021, limited to preoperative curves between 40 and 60° and stratified based on sex assigned at birth. All patients had preoperative and 2-year follow-up and were evaluated for correction, complications, surgery metrics, and patient reported outcomes. Results: 1714 patients were included in this study: 1381 girls, 333 boys. At time of surgery, the mean age was 15.4 ± 2 years for girls and 16.4 ± 2 years for boys. Boys were significantly taller and heavier than the girls. The preoperative curve magnitude was equivalent (major Cobb 50° in girls and boys, p = 0.799). Boys and girls had median 10 levels instrumented [IQR 2] (p = 0.012). At 2-year follow-up, girls with primary thoracic curves had better coronal curve measurements (22° ± 7 vs 23° ± 8, p = 0.002) and percent correction (56% ± 14 vs 53% ± 16, p = 0.004). For primary lumbar curves, curve measurements and percent correction were not different. SRS scores for 2-year post-operative patient reported outcomes were not different in boys and girls. 191 girls experienced complications compared to 48 boys (14% of their cohorts, p = 0.31). 67 girls and 14 boys underwent reoperation (5% vs 4%, p = 0.61). Conclusions: At 2 years following spinal fusion for AIS, boys and girls with moderate curves exhibit similar postoperative curve correction and SRS scores. Complication rates had no difference by patient sex.