Hwee Weng Dennis Hey1, Kimberly-Anne Tan2, Brian Zhaojie Chin2, Gabriel Liu2, Hee-Kit Wong2. 1. University Orthopaedics, Hand and Reconstructive Microsurgery Cluster (UOHC), National University Health System, Singapore, Singapore. Electronic address: dennis_hey@nuhs.edu.sg. 2. University Orthopaedics, Hand and Reconstructive Microsurgery Cluster (UOHC), National University Health System, Singapore, Singapore.
Abstract
BACKGROUND CONTEXT: Imaging for adult spinal deformity is conventionally performed in a directed manner to assess the most upright standing posture one can assume. However, this method does not reflect an individual's natural, relaxed posture, which is the posture a patient likely reverts to postoperatively, and also the posture likely to explain spinal pathologies. PURPOSE: To identify radiographic differences between directed and natural, relaxed standing postures in young healthy subjects. STUDY DESIGN: A randomized, prospective, radiographic study. PATIENT SAMPLE: Sixty healthy 21-year-old subjects (48 male, 12 female). OUTCOME MEASURES: Radiographic parameters including sagittal vertical axis (SVA), C2 SVA, C2-7 SVA global cervical angle, T1-slope, global thoracic angle (GTA), thoracolumbar angle (TLA), global lumbar angle (GLA), sacral slope, pelvic tilt (PT), pelvic incidence, femoral alignment angle (FAA), and knee alignment angle (KAA). METHODS: The EOS whole body radiographs of patients in directed and natural, relaxed standing postures were obtained, with subsequent comparison of radiographic parameters. Differences in Roussouly curve types, sagittal curve apices, and end vertebrae were also evaluated. Univariate analyses using Wilcoxon sign-rank, paired t tests, and paired chi-square tests were performed. RESULTS: Compared with directed standing, natural, relaxed standing results in a more kyphotic spinal profile marked by a significantly less lordotic GLA, larger GTA, TLA, and T1-slope. The PT+FAA demonstrated true hip movement during sagittal balancing. Lower thoracic and lumbar apices, lower thoracolumbar end vertebrae, and lower Roussouly curve types were observed during natural, relaxed standing. CONCLUSIONS: Our study found significant differences in sagittal radiographic parameters between directed standing and the natural, relaxed standing posture, with the latter demonstrating a more kyphotic spinal profile in terms of magnitude and span, as well as complementary changes in cervical and spinopelvic alignment. The natural, relaxed standing posture, a marker for energy conservation principles in standing, may infer value in less aggressive lordotic restoration, as well as concentration of lordosis in the lower lumbar spine.
RCT Entities:
BACKGROUND CONTEXT: Imaging for adult spinal deformity is conventionally performed in a directed manner to assess the most upright standing posture one can assume. However, this method does not reflect an individual's natural, relaxed posture, which is the posture a patient likely reverts to postoperatively, and also the posture likely to explain spinal pathologies. PURPOSE: To identify radiographic differences between directed and natural, relaxed standing postures in young healthy subjects. STUDY DESIGN: A randomized, prospective, radiographic study. PATIENT SAMPLE: Sixty healthy 21-year-old subjects (48 male, 12 female). OUTCOME MEASURES: Radiographic parameters including sagittal vertical axis (SVA), C2 SVA, C2-7 SVA global cervical angle, T1-slope, global thoracic angle (GTA), thoracolumbar angle (TLA), global lumbar angle (GLA), sacral slope, pelvic tilt (PT), pelvic incidence, femoral alignment angle (FAA), and knee alignment angle (KAA). METHODS: The EOS whole body radiographs of patients in directed and natural, relaxed standing postures were obtained, with subsequent comparison of radiographic parameters. Differences in Roussouly curve types, sagittal curve apices, and end vertebrae were also evaluated. Univariate analyses using Wilcoxon sign-rank, paired t tests, and paired chi-square tests were performed. RESULTS: Compared with directed standing, natural, relaxed standing results in a more kyphotic spinal profile marked by a significantly less lordotic GLA, larger GTA, TLA, and T1-slope. The PT+FAA demonstrated true hip movement during sagittal balancing. Lower thoracic and lumbar apices, lower thoracolumbar end vertebrae, and lower Roussouly curve types were observed during natural, relaxed standing. CONCLUSIONS: Our study found significant differences in sagittal radiographic parameters between directed standing and the natural, relaxed standing posture, with the latter demonstrating a more kyphotic spinal profile in terms of magnitude and span, as well as complementary changes in cervical and spinopelvic alignment. The natural, relaxed standing posture, a marker for energy conservation principles in standing, may infer value in less aggressive lordotic restoration, as well as concentration of lordosis in the lower lumbar spine.
Authors: Scott L Zuckerman; Zeeshan M Sardar; Christopher S Lai; Gerard F Marciano; Mena G Kerolus; Ian A Buchanan; Alex S Ha; Meghan Cerpa; Michael P Kelly; Stéphane Bourret; Kazuhiro Hasegawa; Hee-Kit Wong; Gabriel Liu; Hwee Weng Dennis Hey; Hend Riahi; Jean-Charles Le Huec; Lawrence G Lenke Journal: Eur Spine J Date: 2021-05-19 Impact factor: 3.134