Fig. 2

Examples of two patients with similar lumbar coronal deformity but markedly different sagittal alignment. For the first patient with (a) lumbar curve of 24.2° at T12-L4, (b) sagittal parameters included lumbar lordosis of 50.8°, reciprocal thoracic kyphosis of 39.4°, pelvic incidence of 60.2°, pelvic tilt of 25.6°, sacral slope of 34.6°, Pelvic incidence – lumbar lordosis of 9.4°. Despite a similar (c) coronal curve magnitude (23.6° at T12-L4), there was a (d) greater mismatch between pelvic and spinal parameters (− 14.2°) with hypokyphotic thoracic spine (15.4°). Other sagittal parameters included pelvic incidence of 32.9°, pelvic tilt of − 2.8°, sacral slope of 35.7°, and lumbar lordosis of 47.0°