Characterizing spinal curves: addressing variability beyond identical cobb angles

Traditional methods for evaluating spinal curves, such as the Cobb angle, are limited in their ability to capture the full complexity of spinal deformities. This manuscript presents a novel method that builds on Cobb's principle and Ferguson's approach to provide a more comprehensive assessment of spinal curves. The method involves identifying the centroid-based endpoints of the curve to define its "radius of curvature" and calculating the true curve length through a three-point measurement, including the apical vertebra. The curve's type and sharpness are determined using ratios of distances derived from apical and adjacent lines, enabling detailed geometric characterization.This approach allows for precise analysis of complex deformities, such as continuous kyphotic curves in ankylosing spondylitis, and facilitates improved preoperative planning by aligning surgical strategies with the geometry of the curve. Additionally, it extends to evaluating bent rods in spinal instrumentation, ensuring accurate alignment. The method's ability to integrate multiple curve characteristics addresses critical limitations of existing techniques and holds potential for enhancing outcomes in both clinical and research settings.