Investigation of the Phenomenon of Coronal-Sagittal Curvature Coupling on Curve Progression: An Exploratory Study using 3-D Ultrasound.

A 3-D ultrasound system was determined to provide reliable and valid results for scoliosis assessment in the coronal and sagittal planes. The objective of this study was to investigate whether 3-D ultrasound can detect coronal-sagittal coupling and to study its potential effect on curve progression in patients with adolescence idiopathic scoliosis (AIS) as per the traditional Cobb angle classification. Radiographic and ultrasonic coronal and sagittal curvatures of 126 patients with AIS were evaluated. Thoracic kyphosis (TK) and lumbar lordosis (LL) with different coronal deformity were compared correspondingly based on either main thoracic or (thoraco)lumbar curve groups. The TK and LL of patients with single curves were also compared with study the curve effect on sagittal curvatures. A prospective cohort of 51 patients were followed for an average of 23 months for preliminary progression investigation. TKs in patients with larger main thoracic Cobb angles was significantly smaller than those with smaller main thoracic Cobb angles, judging by the results obtained from ultrasound and X-ray. The TKs of patients with only single right main thoracic curves were significantly smaller than those of patients with only single left (thoraco)lumbar curves. In addition, patients with progressive curves were observed to be relative hypokyphotic during early visits.