Assessment of Maximum Spinal Deformity in Scoliosis: A Literature Review

Purpose: The plane of maximum curvature (PMC), end-apical-end vertebrae plane (EAEP), and best-fit plane (BFP) have been used to describe the three-dimensional (3D) features of scoliosis but no thorough analyses were conducted. This study aimed to systematically review these descriptors about their potential differences, measurement techniques, and applications in scoliosis. Methods: Articles were retrieved from six databases and Google Scholar search engine using the keywords “maximum spinal deformity” and “scoliosis” combined with “And”. Results: BFP was found superior to EAEP and PMC in describing the 3D features of scoliosis; however, whether this advantage changes when BFP or EAEP orientation is simplified remains unknown. With the development of 3D reconstruction technique, radiographs and ultrasound images can be used to estimate maximum spinal deformity. The three descriptors have been applied in 3D assessment, progression monitoring, and classification of scoliosis, as well as evaluation of orthotic and surgical treatments but are rarely considered in major clinical decision-making. Conclusion: More evidence is needed to support the superiority of PMC and simplified EAE and BFP, the accuracy of radiographic and ultrasound techniques, and the application of these descriptors to clinical decision-making. Further studies are deserved.