Progression of congenital scoliosis is least likely in which of the following vertebral anomalies -

Congenital vertebral anomalies causing scoliosis are : Hemivertebrae Wedge vertebra Unsegmented bar Block vertebra Combination : unsegmented bar with hemivertebrae Amongst these minimum chances of progression are with block vertebrae and maximum with the combination of unsegmented bar & hemivertebrae. Unsegmented bar - with hemivertebra > unsegmented bar > hemivertebra > wedge vertebra > block vertebra