Prevalence Rate of Adolescent Idiopathic Scoliosis: Results of School-based Screening in Surabaya, Indonesia.

Scoliosis is a lateral spinal deformity of 10 degrees or more, resulting in a C-shaped or S-shaped curve of the spine. Information about adolescent idiopathic scoliosis (AIS) prevalence rate is important not only for paediatric health care planning strategy but also for parent's awareness. This study aims to find the suitable inclination cut-off angle and the prevalence rate of AIS in Surabaya, Indonesia. This is a descriptive cross-sectional study conducted in 2010. We performed stratified random sampling of 784 Elementary and Junior High School students in Surabaya between 9-16 years of age. Scoliosis screening was performed by the Adam's forward bending test (FBT). The students with positive FBT were measured for the inclination angle with scoliometer, and then subjected to radiologic examination. Prevalence rate, gender ratio, and the cut-off point value of inclination angle were determined by a descriptive statistics analysis. Adam's forward bending test was positive in 50 students (6,37%). Among them, 23 students (2,93%) four males and 19 females had Cobb angle of ≥10°. The 5° cutoff point value of inclination angle had a 95.6% sensitivity, an 18.5% specificity, a 50% positive predictive value (PPV), and a 83.33% negative predictive value (NPV); while the 7° cut-off point had a 78.26% sensitivity, a 88.88% specificity, a 85.7% PPV, and a 82.7% NPV. The prevalence rate of AIS in Surabaya is 2.93% and the 7° cut-off point of inclination angle is suitable for school-based screening.