Hongwei Wang1, Xiaohong Wang2, Wenchuan Chen3, Fuqiang Zhao2, Liangbi Xiang4, Yue Zhou5, Chengkung Cheng6. 1. Department of Orthopedics, General Hospital of Shenyang Military Area Command of Chinese People's Liberation Army, Shenyang, Liaoning 110016, China. 2. Naton Institute of Medical Technology and Beijing Medical Implant Engineering Research Center, Beijing 100094, China. 3. Institute of Biomedical Engineering, National YangMing University, Taibei 112, Taiwan, China. 4. Department of Orthopedics, General Hospital of Shenyang Military Area Command of Chinese People's Liberation Army, Shenyang, Liaoning 110016, China. Email: xiangliangbi1963@163.com. 5. Department of Orthopedics, Xinqiao Hospital, the Third Military Medical University, Chongqing 400037, China. 6. School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
Abstract
BACKGROUND: A large amount of biomechanical and clinical evidence from previous studies suggest the efficiency of the two different posterior lumber non-fusion methods, interspinous distraction device (ISDD) and facet screw fixation system (FSS), but the biomechanical comparison of ISDD and FSS has not been thoroughly clarified. METHODS: In the current study, finite element methods were used to investigate the biomechanical comparison of ISDD and FSS. The range of motion (ROM), intradiscal pressure (IDP) and the protective effects gained by maintaining disc heights were evaluated. RESULTS: The ROM was similar between the two non-fusion methods under static standing, flexion and lateral bending. The FSS appeared to be more effective in resisting extension. At the implanted level L3/4, FSS displayed better results for maintaining and increasing posterior disc heights. At the L4/5 level in extension and lateral bending, FSS was better than ISDD, with comparable results observed in other motions. Comparing the posterior and lateral disc heights, FSS appeared to be more effective than ISDD. FSS also had a minor effect on the inferior adjacent segment than ISDD. FSS was more effective in reducing IDP than ISDD in extension. CONCLUSION: Through the finite element analysis study, it can be seen that FSS demonstrates more beneficial biomechanical outcomes than does ISDD, such as being more effective in resisting extension, maintaining and increasing lumbar disc heights and reducing the inferior adjacent IDP in extension.
BACKGROUND: A large amount of biomechanical and clinical evidence from previous studies suggest the efficiency of the two different posterior lumber non-fusion methods, interspinous distraction device (ISDD) and facet screw fixation system (FSS), but the biomechanical comparison of ISDD and FSS has not been thoroughly clarified. METHODS: In the current study, finite element methods were used to investigate the biomechanical comparison of ISDD and FSS. The range of motion (ROM), intradiscal pressure (IDP) and the protective effects gained by maintaining disc heights were evaluated. RESULTS: The ROM was similar between the two non-fusion methods under static standing, flexion and lateral bending. The FSS appeared to be more effective in resisting extension. At the implanted level L3/4, FSS displayed better results for maintaining and increasing posterior disc heights. At the L4/5 level in extension and lateral bending, FSS was better than ISDD, with comparable results observed in other motions. Comparing the posterior and lateral disc heights, FSS appeared to be more effective than ISDD. FSS also had a minor effect on the inferior adjacent segment than ISDD. FSS was more effective in reducing IDP than ISDD in extension. CONCLUSION: Through the finite element analysis study, it can be seen that FSS demonstrates more beneficial biomechanical outcomes than does ISDD, such as being more effective in resisting extension, maintaining and increasing lumbar disc heights and reducing the inferior adjacent IDP in extension.