Assessing the biomechanics of scheuermann’s kyphosis affected thoracolumbar spine in forward flexion at the tissue-level using a finite element model

Abstract Thoracolumbar kyphosis (TLK) secondary to Scheuermann’s disease often leads to low back pain, which may be related to altered biomechanical properties of the spine. However, There is a lack of biomechanical studies in the literature that comprehensively evaluate tissue-level stresses and st...

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Main Authors: Chunli Wan, Xiaowen Shen, Xixi Wu, Cui Yu, Yi Shao, Ruiping Zhang, Jiao Shang, Jianan Li, Yuting Zhang, Yongqiang Li
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-12968-7
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author Chunli Wan
Xiaowen Shen
Xixi Wu
Cui Yu
Yi Shao
Ruiping Zhang
Jiao Shang
Jianan Li
Yuting Zhang
Yongqiang Li
author_facet Chunli Wan
Xiaowen Shen
Xixi Wu
Cui Yu
Yi Shao
Ruiping Zhang
Jiao Shang
Jianan Li
Yuting Zhang
Yongqiang Li
author_sort Chunli Wan
collection DOAJ
description Abstract Thoracolumbar kyphosis (TLK) secondary to Scheuermann’s disease often leads to low back pain, which may be related to altered biomechanical properties of the spine. However, There is a lack of biomechanical studies in the literature that comprehensively evaluate tissue-level stresses and strains in the thoracolumbar spine affected by Scheuermann’s kyphosis, particularly during functional motions such as forward flexion. This study analyzed biomechanical changes during forward flexion in TLK patients using musculoskeletal dynamics and finite element modeling. Twenty TLK patients and twenty healthy individuals were recruited. Kinematic data (joint angles), kinetic data (joint reaction forces and moments), and electromyographic (EMG) data were collected at different bending angles using Vicon 3D motion capture and surface electromyography. Physiologic motions captured from in vivo experiment was simulated using OpenSim, with inverse dynamics and optimization used to calculate vertebral joint angles, muscle forces, and intervertebral reaction forces, serving as boundary conditions for ANSYS finite element models. Subject-specific finite element models for both groups were constructed in ANSYS using computed tomography (CT) DICOM files. The CT-based finite element models were used to compute von Mises stress distributions—a mechanical parameter indicating combined tissue stress and potential risk of overload—in the vertebral body, intervertebral discs, and articular cartilage at different forward flexion angles under the applied loadig conditions. At different forward bending angles, TLK patients exhibited high stress distribution in the L1-S1 segment vertebral articular processes. Compared with healthy individuals, the stress distribution in the S1 segment was uneven, with peak stress reaching up to to 2.8 times higher (180% increase) than that of healthy individuals. TLK patients exhibit stress concentration in the annulus fibrosus region of the intervertebral disc, while the stress distribution in the nucleus pulposus region is relatively uniform. The peak stress in the intervertebral disc during different movements can be up to 2.33 times higher (133% increase) than in healthy individuals. In TLK patients, stress concentration was observed in the articular cartilage of all segments except for the L5/S1 segment. The peak stress in the articular cartilage during different movements was up to 12.02 times higher (1,102% increase) than in healthy individuals. These results suggest that TLK patients experience elevated and uneven spinal tissue stress during forward flexion, which may contribute to increased risk of degeneration and back pain.
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spelling doaj-art-da0c8a251a2e449a84bd6b75daa0a2182025-08-20T03:05:22ZengNature PortfolioScientific Reports2045-23222025-07-0115111210.1038/s41598-025-12968-7Assessing the biomechanics of scheuermann’s kyphosis affected thoracolumbar spine in forward flexion at the tissue-level using a finite element modelChunli Wan0Xiaowen Shen1Xixi Wu2Cui Yu3Yi Shao4Ruiping Zhang5Jiao Shang6Jianan Li7Yuting Zhang8Yongqiang Li9The First Affiliated Hospital with Nanjing Medical UniversityThe Affiliated Huaian No. 1 People’s Hospital of Nanjing Medical UniversityNanjing Medical UniversityNanjing Medical UniversityNanjing Medical UniversityPanjin Liao-he Oil Field Gem Flower HospitalPanjin Liao-he Oil Field Gem Flower HospitalThe First Affiliated Hospital with Nanjing Medical UniversityThe First Affiliated Hospital with Nanjing Medical UniversityThe First Affiliated Hospital with Nanjing Medical UniversityAbstract Thoracolumbar kyphosis (TLK) secondary to Scheuermann’s disease often leads to low back pain, which may be related to altered biomechanical properties of the spine. However, There is a lack of biomechanical studies in the literature that comprehensively evaluate tissue-level stresses and strains in the thoracolumbar spine affected by Scheuermann’s kyphosis, particularly during functional motions such as forward flexion. This study analyzed biomechanical changes during forward flexion in TLK patients using musculoskeletal dynamics and finite element modeling. Twenty TLK patients and twenty healthy individuals were recruited. Kinematic data (joint angles), kinetic data (joint reaction forces and moments), and electromyographic (EMG) data were collected at different bending angles using Vicon 3D motion capture and surface electromyography. Physiologic motions captured from in vivo experiment was simulated using OpenSim, with inverse dynamics and optimization used to calculate vertebral joint angles, muscle forces, and intervertebral reaction forces, serving as boundary conditions for ANSYS finite element models. Subject-specific finite element models for both groups were constructed in ANSYS using computed tomography (CT) DICOM files. The CT-based finite element models were used to compute von Mises stress distributions—a mechanical parameter indicating combined tissue stress and potential risk of overload—in the vertebral body, intervertebral discs, and articular cartilage at different forward flexion angles under the applied loadig conditions. At different forward bending angles, TLK patients exhibited high stress distribution in the L1-S1 segment vertebral articular processes. Compared with healthy individuals, the stress distribution in the S1 segment was uneven, with peak stress reaching up to to 2.8 times higher (180% increase) than that of healthy individuals. TLK patients exhibit stress concentration in the annulus fibrosus region of the intervertebral disc, while the stress distribution in the nucleus pulposus region is relatively uniform. The peak stress in the intervertebral disc during different movements can be up to 2.33 times higher (133% increase) than in healthy individuals. In TLK patients, stress concentration was observed in the articular cartilage of all segments except for the L5/S1 segment. The peak stress in the articular cartilage during different movements was up to 12.02 times higher (1,102% increase) than in healthy individuals. These results suggest that TLK patients experience elevated and uneven spinal tissue stress during forward flexion, which may contribute to increased risk of degeneration and back pain.https://doi.org/10.1038/s41598-025-12968-7Spinal biomechanicsMusculoskeletal dynamicsFinite element validationVon mises stressScheuermann’s diseaseThoracolumbar kyphosis
spellingShingle Chunli Wan
Xiaowen Shen
Xixi Wu
Cui Yu
Yi Shao
Ruiping Zhang
Jiao Shang
Jianan Li
Yuting Zhang
Yongqiang Li
Assessing the biomechanics of scheuermann’s kyphosis affected thoracolumbar spine in forward flexion at the tissue-level using a finite element model
Scientific Reports
Spinal biomechanics
Musculoskeletal dynamics
Finite element validation
Von mises stress
Scheuermann’s disease
Thoracolumbar kyphosis
title Assessing the biomechanics of scheuermann’s kyphosis affected thoracolumbar spine in forward flexion at the tissue-level using a finite element model
title_full Assessing the biomechanics of scheuermann’s kyphosis affected thoracolumbar spine in forward flexion at the tissue-level using a finite element model
title_fullStr Assessing the biomechanics of scheuermann’s kyphosis affected thoracolumbar spine in forward flexion at the tissue-level using a finite element model
title_full_unstemmed Assessing the biomechanics of scheuermann’s kyphosis affected thoracolumbar spine in forward flexion at the tissue-level using a finite element model
title_short Assessing the biomechanics of scheuermann’s kyphosis affected thoracolumbar spine in forward flexion at the tissue-level using a finite element model
title_sort assessing the biomechanics of scheuermann s kyphosis affected thoracolumbar spine in forward flexion at the tissue level using a finite element model
topic Spinal biomechanics
Musculoskeletal dynamics
Finite element validation
Von mises stress
Scheuermann’s disease
Thoracolumbar kyphosis
url https://doi.org/10.1038/s41598-025-12968-7
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