Scoliometer Measurements are Sensitive to Non-level Pelvis: Implications for Scoliosis Screening
Abstract
Introduction: In scoliosis screening the angle of trunk rotation (ATR) cut off value is still debated. Static pelvic obliquity is common in growing age. It is not known whether the scoliometer values are sensitive to non-level pelvis.
Objective: was to verify whether the ATR depends on functional pelvic obliquity by measuring the ATR while the pelvis was asymetrically raised with shoe lift.
Methods: Study group comprised 25 girls, aged 15,6 ± 1,8 (range 13–19 years), with double major curvature (Lenke 3). Cobb angle was 60,7° ± 17,3° (range 38,0° to 93,0°) in thoracic and 54,4° ± 18,0° (range 35,0° to 92,0°) in lumbar spine. Control group comprised 25 healthy girls, aged 14,2 ± 0,9 (range 12 to 16 years). The Bunnell scoliometer readings were noted at four levels: proximal thoracic, main thoracic, thoracolumbar/lumbar and sacral. All measurements were repeated in the same subjects and at the same levels, while leveling one side of the pelvis using shoe lift.
Results: The ATRs changed significantly while 1 or 2cm shoe lift was applied. The ATRs alternatively raised and lowered within adjacent spinal segments. The difference depended on shoe lift thickness and on spinal level: 1,5°–4,5° within thoracolumbar/lumbar curve; 1,2°–3,8° within main thoracic curve, and 0,7° to 2,4° within proximal thoracic curve.
Conclusion: Bunnell scoliometer measurement is sensitive to a non-level pelvis.
Significance: The bias in ATR measurements up to 4.5° may result from pelvis position. When using the scoliometer in school screening, the sitting forward bending position should be considered.