Biomechanical Evaluation of the Volume and Location of PMMA bone cement in Vertebroplasty

• Main Authors: Zheng-Xing Chen, 陳政行
• Other Authors: Wen-Pin Chen
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/dsscsk

碩士 === 中原大學 === 醫學工程研究所 === 91 === Osteoporotic vertebral compression fracture is one of the most common diseases that attack the elder population especially in postmenopausal women. Most of these patients received conservative treatment such as medication, bracing and rest, but sometimes in vain. Instrumentation and fusion surgery can be used in some cases, but most of these patients are older and with higher operative risk that are not eligible for these operations. Vertebroplasty involves inserting bone cement (PMMA) into the center of the collapsed spinal vertebra in order to stabilize and strengthen the crushed bone. The two objectives of this study are, (1) to develop a set of instruments used for vertebroplasty with disposable parts (trocar, needle, and syringe), and reusable part (introducer) and to reduce the expense for vertebroplasty, (2) to use a validated finite element model to evaluate the effects of bone cement with different volumes and locations in vertebroplasty and the stress distribution of the vertebral bodies after vertebroplasty. According to our analysis, there is no significant difference between 6-ml, one-sided and 10-ml, two-sided models. The effect of 6-ml, one-sided model was similar to 6-ml, two-sided and even better, but no significant difference. On the biomechanical viewpoint, vertebroplasty is an effective method in increasing biomechanical strength of vertebral bodies. The effects were related to the volumes of bone cement, but not totally proportional to them. There were similar results between the same volumes but different distributions (one-sided, two-sided). One-sided approach seems to be a safer method. We established another model with five motion segments to evaluate the effect of vertebroplasty on the adjacent vertebrae. The result showed that there was no significant effect on the adjacent vertebrae if the height of the injured vertebral body was recovered to the initial height. The introducer we designed is easy-to-use, less expensive and we can effectively control the amount of PMMA to be injected.