Tae Hyun Park1, Su Heon Woo2, Sung Jae Lee3, Dong Min Sohn3, Chun Kee Chung4, Yongjung Jay Kim5, Seil Sohn6. 1. R&D Center, Medyssey Co, Ltd, Jechon, Republic of Korea; Department of Biomedical Engineering, College of Biomedical Science& Engineering, Inje University, Gyeongnam, Republic of Korea; Department of Neurosurgery, CHA University, CHA Bundang Medical Center, Republic of Korea. 2. R&D Center, Medyssey Co, Ltd, Jechon, Republic of Korea. 3. Department of Biomedical Engineering, College of Biomedical Science& Engineering, Inje University, Gyeongnam, Republic of Korea. 4. Department of Neurosurgery, Seoul National University College of Medicine, Republic of Korea; Neuroscience Research Institute, Seoul National University Medical Research Center, Republic of Korea; Clinical Research Institute, Seoul National University Hospital, Republic of Korea; Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Republic of Korea. 5. Department of Orthopedics, Columbia University, College of Physicians and Surgeons, New York, NY, USA. 6. Department of Neurosurgery, CHA University, CHA Bundang Medical Center, Republic of Korea. Electronic address: sisohn@cha.ac.kr.
Abstract
BACKGROUND: We aim to investigate using finite element model (FEM) whether the use of a cross-link is a risk factor for rod fracture at the pedicle subtraction osteotomy (PSO) site. METHODS: The geometry and dimensions of the FEM were obtained from a high-resolution computed tomography scan data of a 65 years old female patient with spinal sagittal imbalance. The intact model was modified to place PSO on the L4 spine. A cross-link was placed at the PSO site. A multisegment spinal fusion model from L1 to the pelvis was used to compare and analyze the peak von Mises stress (PVMS) values of the implants. A compressive follower load of 400 N was added to the validated intact lumbar spinal model in the follower load path direction. RESULTS: After PSO surgery, the PVMS of the rod was significantly increased during flexion and extension at the PSO site. With the cross-link at the PSO site, the PVMS of the rod was further significantly increased during flexion and extension. CONCLUSION: The cross-link at the PSO site increased the risk of rod facture, especially during flexion and extension stress.
BACKGROUND: We aim to investigate using finite element model (FEM) whether the use of a cross-link is a risk factor for rod fracture at the pedicle subtraction osteotomy (PSO) site. METHODS: The geometry and dimensions of the FEM were obtained from a high-resolution computed tomography scan data of a 65 years old female patient with spinal sagittal imbalance. The intact model was modified to place PSO on the L4 spine. A cross-link was placed at the PSO site. A multisegment spinal fusion model from L1 to the pelvis was used to compare and analyze the peak von Mises stress (PVMS) values of the implants. A compressive follower load of 400 N was added to the validated intact lumbar spinal model in the follower load path direction. RESULTS: After PSO surgery, the PVMS of the rod was significantly increased during flexion and extension at the PSO site. With the cross-link at the PSO site, the PVMS of the rod was further significantly increased during flexion and extension. CONCLUSION: The cross-link at the PSO site increased the risk of rod facture, especially during flexion and extension stress.