2023, Vol. 27 ›› Issue (27): 4393-4400

Research status and progress of establishment and validation of finite element model of adolescent idiopathic scoliosis

Peng Lu1, 2, Duan Zhili1, 2, Li Zhenyu3, 4, Li Junhui5, Li Yunhong4, Wang Song1, 6, Liu Weiqiang1, 2, 6   

Abstract: BACKGROUND: Adolescent idiopathic scoliosis has a high prevalence and complex condition in China and has a significant risk to the physical and mental health of adolescents. The establishment of finite element models based on patient medical images can effectively analyze spinal stresses, simulate the recovery effects of different treatments, and provide a scientific basis for the selection of patient treatment modalities. However, there are many different ways to build finite element models and no unified standard has been formed yet; the quality of models varies and the validation methods need to be improved.  
OBJECTIVE: The current status of modeling studies in adolescent idiopathic scoliosis in recent years is reviewed in terms of software selection, modeling of key structures (vertebral body, disc, ligament, and trunk models), and material allocation. The research progress of model validation is outlined from the perspectives of geometry, comparison of existing literature, and experimental validation. The deficiencies and development directions of finite element models are summarized to provide references for related studies.
METHODS: The first author searched the Web of Science and China National Knowledge Infrastructure databases in December 2021 for relevant literature published from January 2010 to the present, using “adolescent idiopathic scoliosis, finite element, biomechanics” as Chinese and English search terms. The highly cited authoritative articles were traced, and finally 83 articles were included for analysis.  
RESULTS AND CONCLUSION: (1) Finite element analysis method can reconstruct the three-dimensional model of spine, simulate the physiological state of spine through biomechanical analysis, and provide theoretical basis and scheme reference for conservative treatment and surgical treatment of adolescent idiopathic scoliosis. (2) The establishment method of finite element model in China is different from that outside China. Domestic researchers use full spinal CT to reconstruct the vertebrae through reverse engineering and establish intervertebral discs, ligaments, articular cartilage endplate, up and down structure according to the model of vertebrae. However, the foreign researchers use multiple plane X-ray devices such as the EOS imaging system, which is lack of description of the model establishment process. (3) Although the specific software selection in the process of model building is different, the software classification includes medical image processing software, three-dimensional modeling software and finite element analysis software. (4) The finite element material assignment of vertebrae and intervertebral discs has formed a unified standard, but the material assignment of ligament model is also different due to different unit settings, and the assignment of ligament will significantly affect the results of the model. (5) The verification methods of finite element models mainly include geometric verification compared with original medical images, mechanical verification compared with existing literature results and clinical trial verification of finite element analysis results.

Key words: adolescent idiopathic scoliosis, finite element model, biomechanics, modeling method, software selection, material assignment, validity verification, development direction