Shibin Shu1,2, Zongshan Hu1,2,3, Hongda Bao1,2, Jian Shi4, Anning Hu4, Michael Grelat5, Zhen Liu1,2, Xu Sun1,2, Bangping Qian1,2, Jack C Y Cheng2,3, Tsz-Ping Lam2,3, Winnie W C Chu6, Yong Qiu1,2, Zezhang Zhu1,2. 1. Department of Spine Surgery, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China. 2. Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, Nanjing 210008, China. 3. Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China. 4. Department of Radiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China. 5. Department of Neurosurgery, Dijon University Hospital, Dijon, France. 6. Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China.
Abstract
BACKGROUND: The interactions between the spine, pelvis, and lower limbs are dynamic based on the "cone of economy" concept; thus, different global radiographic parameters could be regarded as reflections of different centers of gravity. We conducted this retrospective study to evaluate the offsets of different centers of gravity in asymptomatic populations and to investigate how the global sagittal alignment is supported. METHODS: The following parameters were measured: cervical lordosis, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), the ratio between PT and PI (PT/PI), sacral slope, PI minus LL (PI-LL), the sagittal vertical axis (SVA), cranial SVA to ankle center (Cr-A), CrSVA to the femoral head center (Cr-FH), C2SVA to the femoral head center (C2-FH), pelvic translation (P. Shift), and knee angle (KA). Participants were divided into subgroups based on the PT/PI ratio. Mean values were compared using the t-test, and correlations were assessed using Pearson's coefficient. RESULTS: A total of 82 asymptomatic adults were enrolled. The average PT/PI in subgroup 1 was the smallest, showing that individuals in this group may have limited pelvic retroversion. No significant differences in Cr-FH, Cr-A, or C2-FH were found between subgroups (all P>0.1), implying that global alignment was well supported in each group. Specifically, C2-FH showed minor changes between subgroups (P=0.998), showing that C2-FH may be a target for sagittal compensation. There were positive correlations between PT/PI and both P. Shift and SVA (r=0.930 and r=0.606, respectively). However, Cr-FH, Cr-A, and C2-FH were not significantly correlated with P. Shift or PT/PI (all P>0.05). Weak correlations existed between Cr-A, Cr-FH, and age (all P>0.2). CONCLUSIONS: This study revealed that the Cr-FH and C2-FH offsets are stable across the population and could be maintained by regulating only the sagittal spinal curvature when pelvic compensation is limited. Cr-FH is not affected by age in the asymptomatic population. Thus, the stable Cr-FH and C2-FH could provide references for surgeons during the surgical decision-making process in patients with adult spinal deformity with sagittal malalignment. 2020 Quantitative Imaging in Medicine and Surgery. All rights reserved.
BACKGROUND: The interactions between the spine, pelvis, and lower limbs are dynamic based on the "cone of economy" concept; thus, different global radiographic parameters could be regarded as reflections of different centers of gravity. We conducted this retrospective study to evaluate the offsets of different centers of gravity in asymptomatic populations and to investigate how the global sagittal alignment is supported. METHODS: The following parameters were measured: cervical lordosis, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), the ratio between PT and PI (PT/PI), sacral slope, PI minus LL (PI-LL), the sagittal vertical axis (SVA), cranial SVA to ankle center (Cr-A), CrSVA to the femoral head center (Cr-FH), C2SVA to the femoral head center (C2-FH), pelvic translation (P. Shift), and knee angle (KA). Participants were divided into subgroups based on the PT/PI ratio. Mean values were compared using the t-test, and correlations were assessed using Pearson's coefficient. RESULTS: A total of 82 asymptomatic adults were enrolled. The average PT/PI in subgroup 1 was the smallest, showing that individuals in this group may have limited pelvic retroversion. No significant differences in Cr-FH, Cr-A, or C2-FH were found between subgroups (all P>0.1), implying that global alignment was well supported in each group. Specifically, C2-FH showed minor changes between subgroups (P=0.998), showing that C2-FH may be a target for sagittal compensation. There were positive correlations between PT/PI and both P. Shift and SVA (r=0.930 and r=0.606, respectively). However, Cr-FH, Cr-A, and C2-FH were not significantly correlated with P. Shift or PT/PI (all P>0.05). Weak correlations existed between Cr-A, Cr-FH, and age (all P>0.2). CONCLUSIONS: This study revealed that the Cr-FH and C2-FH offsets are stable across the population and could be maintained by regulating only the sagittal spinal curvature when pelvic compensation is limited. Cr-FH is not affected by age in the asymptomatic population. Thus, the stable Cr-FH and C2-FH could provide references for surgeons during the surgical decision-making process in patients with adult spinal deformity with sagittal malalignment. 2020 Quantitative Imaging in Medicine and Surgery. All rights reserved.
Entities:
Keywords:
Pelvic compensation; asymptomatic adults; full body; lower limbs
Authors: Renaud Lafage; Frank Schwab; Vincent Challier; Jensen K Henry; Jeffrey Gum; Justin Smith; Richard Hostin; Christopher Shaffrey; Han J Kim; Christopher Ames; Justin Scheer; Eric Klineberg; Shay Bess; Douglas Burton; Virginie Lafage Journal: Spine (Phila Pa 1976) Date: 2016-01 Impact factor: 3.468
Authors: Themistocles Protopsaltis; Frank Schwab; Nicolas Bronsard; Justin S Smith; Eric Klineberg; Gregory Mundis; Devon J Ryan; Richard Hostin; Robert Hart; Douglas Burton; Christopher Ames; Christopher Shaffrey; Shay Bess; Thomas Errico; Virginie Lafage Journal: J Bone Joint Surg Am Date: 2014-10-01 Impact factor: 5.284
Authors: William C Horton; Courtney W Brown; Keith H Bridwell; Steven D Glassman; Se-Il Suk; Charles W Cha Journal: Spine (Phila Pa 1976) Date: 2005-02-15 Impact factor: 3.468
Authors: Mitsuru Takemoto; Louis Boissière; Felipe Novoa; Jean-Marc Vital; Ferran Pellisé; Francisco Javier Sanchez Pérez-Grueso; Frank Kleinstück; Emre R Acaroglu; Ahmet Alanay; Ibrahim Obeid; Ibrahim Obeid Journal: Eur Spine J Date: 2016-05-25 Impact factor: 3.134
Authors: Rafael Menezes-Reis; Carlos E Garrido Salmon; Gustavo P Bonugli; Debora Mazoroski; Leonor G Savarese; Carlos Fernando P S Herrero; Helton L A Defino; Marcello Henrique Nogueira-Barbosa Journal: Quant Imaging Med Surg Date: 2021-06