Analysis of bone cement distribution in vertebrae using pedicle screws with and without fenestrations

Abstract

With the increase in the life expectancy of the population, there are more and more health complications related to aging, such as osteoporosis. Among the complications resulting from osteoporosis, spinal fractures stand out. In some cases, pedicle screws are used to stabilize the spine. However, when screws are inserted into bone weakened due to osteoporosis, proper fixation of the screw may not occur. To reduce this problem, bone cement is injected into the vertebral body as a way to ensure better stabilization of the screws. One of the main complications of this procedure is related to the leakage of cement out of the vertebral body, causing several problems that affect health. The risks of cement leakage could be reduced by using Computational Fluid Dynamics (CFD) to analyze the distribution of bone cement in the vertebra. Thus, the objective of this research is to evaluate, by means of CFD, the fluid dynamic behavior of PMMA-based bone cement injection into vertebrae through pedicle screws with and without fenestrations. To study the cement flow inside the vertebra, a commercial software was used . The factors influencing the distribution of bone cement were evaluated and compared with results reported in the literature, showing good agreement with each other. The numerical results indicate that the use of fenestrated pedicle screws can improve screw stability and reduce the risk of bone cement leakage.