Validity of computed photogrammetry for detecting idiopathic scoliosis in adolescents

Introduction: Adolescent idiopathic scoliosis (AIS) is a three-dimensional abnormality of the spine, of unknown etiology. It starts at the beginning of puberty and its progression is associated with the growth spurt. Analysis of angular movement and body posture through the static imaging method known as photogrammetry could allow physical therapists to quantify and qualify their body posture/movement assessments. Objective: This study was carried out to evaluate the sensitivity of this instrument for detecting AIS in examinations in schools. Methods: This was a school-based cross-sectional study among fifth to eighth-grade elementary school students in public and private schools in Pelotas. Digital images were collected and radiographic examinations were performed in the anteroposterior and lateral planes. The sensitivity and specificity of the photogrammetry were investigated using three and two degrees of margin for the body surface asymmetry. Results: Two hundred twenty four students underwent the photogrammetry and standard radiological examinations at the schools. The prevalence of AIS was 4.5% (n=10), in eight girls and two boys with mean Cobb of 13.3 degrees; mean vertebral rotation of 1.1 (Nash-Moe); dorsal kyphosis of 29.5 degrees Cobb, iliolumbar angle of 3.6 degrees; and Risser sign of 1.6. With three degrees margin, the sensitivity was 21.4% and the specificity was 90.7%. With two degrees margin, the sensitivity was 50% and the specificity was 61.2%. Conclusions: Based on these results, it was found that computerized photogrammetry could not be used as a screening method for detecting mild scoliosis in schools.