For a cross-sectional radiographic comparison study, the goal was to compare kypholordotic ratios on whole-body radiographs of young, healthy volunteers to understand better whole-body balancing in guided and natural standing postures. Recent research emphasised the necessity of understanding whole-body balancing, recommending using both the more physiological natural standing position and the traditional guided standing posture for imaging. A total of 60 healthy 21-year-old volunteers (36 males and 24 females) were enlisted for the study. EOS whole-body radiographs were taken of subjects in both directed and natural standing positions. The C2-sagittal vertical axis (C2-SVA), C7-sagittal vertical axis (C2-7-SVA), global cervical angles (C0-T1 and C2-C7), regional cervical angles (C0-C2, C2-C4, C4-C7), T1-slope, global thoracic angles (T1-T12 and T1-inflection vertebra [Inf]), thoracolumbar angle (T11-L2), global (FAA). T1-12/T12-S1, T1-Inf/Inf-S1, Tl-Inf/SCA, and (T1-Inf + FAA)/(T1-slope + SCA) kypholordotic ratios were calculated and compared. Natural standing has a higher C2-SVA and C7-SVA, more lordotic global and regional cervical angles (except C0-2 angle), higher T1-slope, larger T1-T12, and T1-Inf kyphotic angles, smaller T12-S1 and Inf-S1 lordotic angles, larger PT, more lordotic SCA, and smaller SS and FAA angles when compared to directed standing. In natural standing, the T1-12/T12-S1 and T1-Inf/Inf-S1 ratios and the (Tl-Inf + FAA)/(T1-slope + SCA) ratio in both postures are approximately 1. The Tl-l2/Tl2-Sl, Tl-Inf/Inf-Sl, and Tl-Inf/SCA ratios differed significantly between positions. Understanding the balance between kyphosis and lordosis, which varies depending on the patient’s posture, was necessary for whole-body balancing. The importance of performing whole-body imaging in the directed standing posture and whole-spine or whole-body imaging in the natural standing posture, to fully understand spinal and whole-body balancing for spinal realignment surgeries kypholordotic ratios obtained in the study.
Link:journals.lww.com/spinejournal/Abstract/2021/12010/Understanding__Kyphosis__and__Lordosis__for.3.aspx
