Evaluation of vertebral rotation by ultrasound for the early detection of adolescent idiopathic scoliosis

This paper reports a new real-time ultrasound method for measuring vertebra l rotation to detect lateral spinal curves of adolescent idiopathic scolios is (AIS) in 50 adolescents referred consecutively to hospital from the scol iosis school screening service in Nottingham, England (girls 39, boys 11, m edian age 15 years). Radiographically the curve types were thoracic 21, tho racolumbar 14 and lumbar 15 with a mean Cobb angle of 17 degrees (range 2-4 0 degrees). Ultrasound laminal rotation was measured in the prone position from TI-SI by one of three observers. The ability of ultrasound laminal rot ation to predict the scoliosis curve (Cobb) angle was compared with surface : back shape angles calculated at 18 levels from angles of trunk inclinatio ns (ATIs) measured by a Scoliometer in the standing forward bending positio n. The findings show that ultrasound laminal rotation land Scoliometer ATI each with a threshold of 8 degrees predicted Cobb angles of 20 degrees or m ore with a sensitivity of 95% (79%), specificity of 68% (35%) and positive predictive value of 64% (43%). Overall, the ultrasound method is significan tly better than the Scoliometer method for discriminating curves with Cobb angles of 20%(p=0.003, McNemar test). The findings suggest that in school s creening for scoliosis ultrasound laminal rotation measured in the communit y may reduce the number of false positives who are referred to hospital and x-rayed.