Finite Element Method In Pelvic Fracture Biomechanics Research

With the increasing number of traffic accidents and work-related injuries, pelvic fracture incidence increased year by year, and now accounts for the total number of full-body fractures of 1% -3%. Although modern medical technology has greatly improved, pelvic fracture case-fatality rate is still 5% -20% and disability up to 50% -60%.Pelvic fracture caused by many because of the tremendous violence which including direct effect or impact extrusion. Since the majority of serious injuries, often combined with heavy bleeding, the high incidence of shock was often observed. As it usually combined with abdominal or genitourinary injuries, the emergency treatment and surgical treatment are very complex. Since the 80's in the 20th century, Open reduction and internal fixation was used in the treatment of unstable pelvic fractures in foreign country. The prognosis was significantly better than non-surgical treatment. Surgical treatment of unstable pelvic fractures is aimed at correction of deformity, early activities, the prevention of late pelvic instability and nonunion, to achieve a painless and functional satisfaction. Pelvic fracture fixation is expected to provide a new solution for achieving better results. For rotary instability and vertical unstable pelvic fractures, early surgical fixation in order to restore pelvic stability can be significantly reduce mortality and disability, improve the latter features. At the same time, a solid internal fixation to make the treatment of complicated injury easier to solve the problem, and also conducive to the treatment of multiple trauma. Foreign scholars found that on the unstable pelvic injury, the satisfaction of surgical treatment rated at 96%. The observation of patient's postoperative function of 57 cases of pelvic fractures in first part of the study had confirmed these views.Finite element method has provided a good way to further explore the biomechanics of pelvic fractures and its treatment. At present, clinical application of CT or MRI three dimensional reconstruction technique can be intuitive, accurate reflection of the human body structure, to provide diagnostic information for clinical and basis. But they still can not carry out for biomechanical analysis, which may cause limitations. Three-dimensional finite element analysis software can do the real analog and precise analysis on the various components of the complex heterogeneity of the structure of the human body. It has become an important instrument in modern human biomechanics research. Since the 70s in 20th century, it had been used in the spine biomechanics research. After the 80's the scope of its application gradually extended to the skull, jaw, bone, teeth and other bony structures. In this study, finite element analysis was adopted by the method of pelvic fracture biomechanics, thereby guiding the clinical diagnosis of pelvic fracture and the treatment. This requires the establishment of an accurate, complete and reliable three-dimensional finite element model of pelvis. Part oneObjective: To explore the methods and efficacy of the surgical treatment of pelvic fractures. .Methods:Since 2002, a total of 57 cases of type B and C pelvic fractures according to the AO classification were treated with open reduction and internal fixation. The operation was proceeded 4-7d after injury, on an average of 5.2d. The fracture reduction quality was assessed by Matta scoring standard and the function was assessed by Iowa scoring standard.Results: The follow-up was ranging from 6 to 25m (an average of 14.4m). According to Matta scoring standard the fracture reduction quality was 100% excellent. According to Iowa scoring standard, 47 cases of this group has returned to the original job (82%) and all patients satisfied with family life. One case of fracture combined with colon rupture occurred incision infection and the total infection rate was 1.75%. No internal fixation failure observed. Part TWOObjective To explore an faster and more precise method for establishment of the three-dimensional finite element model of pelvic.Methods A normal pelvic from an adult male subject was scanned by CT and the images of every cross section were obtained. The images were managed in Dicom standard and analyzed with Mimics and Ansys softwar.Results A three-dimensional finite element model of pelvic was established.Mimics software were used to identify the CT images and write the digital data to Ansys software directly,which increased the accuracy and efficiency of establishment of the three-dimensional finite element model.Conclusion: The construction of three-dimensional finite element pelvic model provides basic data which are critical for accurate analysis of the biomechanical of pelvic fracture.