Open Journal of Orthopedics, 2019, 9, 241-253 https://www.scirp.org/journal/ojo ISSN Online: 2164-3016 ISSN Print: 2164-3008 DOI: 10.4236/ojo.2019.911025 Nov. 29, 2019 241 Open Journal of Orthopedics Calculation of Intervertebral Disc Pressure in the Thoracic and Lumbar Spine in Elderly Women with Kyphosis Using a Novel Musculoskeletal Model with Isolated Thoracic Vertebrae and Rib Cage Jumpei Iida 1 , Naohisa Miyakoshi 1* , Michio Hongo 1 , Takehiro Iwami 2 , Ryo Higuchi 2 , Akira Komatsu 2 , Toshiki Matsunaga 3 , Yoichi Shimada 1 1 Department of Orthopedic Surgery, Akita University Graduate School of Medicine, Akita, Japan 2 Department of Mechanical Engineering, Akita University Faculty of Engineering and Resource Science, Akita, Japan 3 Department of Rehabilitation Medicine, Akita University Hospital, Akita, Japan Abstract Background: Degeneration of the intervertebral disc is one of the causes of kyphosis. Several biomechanical studies have investigated the mechanisms of development of spinal deformity using simulation models. Realistic muscu- loskeletal models are helpful for investigating the pathophysiology and changes in internal forces in patients with kyphosis. However, the association between intervertebral disc pressure and kyphosis has not been fully elucidated to date. Purpose: To calculate intervertebral disc pressure in elderly women with kyphosis using a novel and precise thoracolumbar three-dimensional musculoskeletal model. Materials and Method: Ten female patients with a mean age of 80.0 ± 6.5 years who visited our hospital for medical examination of osteoporosis were included. The subjects were divided into the normal and kyphosis groups depending on their sagittal vertical axis. Intervertebral disc pressures in the thoracic and lumbar spines of subjects were analyzed by in- verse dynamics analysis using a novel three-dimensional musculoskeletal model, and were compared between the groups. Result: Significant differences in lumbar lordosis (LL) were observed between the two groups. Furthermore, the kyphosis group was older and shorter. In the kyphosis group, the upper thoracic vertebrae (T1 - T6) showed significantly higher intervertebral pres- sure than the normal group. Conclusion: Intervertebral disc pressure in the thoracic and lumbar spines of patients with spinal deformities was evaluated using a novel thoracolumbar three-dimensional musculoskeletal model. Us- How to cite this paper: Iida, J., Miyakoshi, N., Hongo, M., Iwami, T., Higuchi, R., Komatsu, A., Matsunaga, T. and Shimada, Y. (2019) Calculation of Intervertebral Disc Pressure in the Thoracic and Lumbar Spine in Elderly Women with Kyphosis Using a Novel Musculoskeletal Model with Isolated Thoracic Vertebrae and Rib Cage. Open Journal of Orthopedics, 9, 241-253. https://doi.org/10.4236/ojo.2019.911025 Received: October 10, 2019 Accepted: November 26, 2019 Published: November 29, 2019 Copyright © 2019 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access