| Summary: | 碩士 === 中原大學 === 醫學工程研究所 === 90 === In spinal fusion surgery, bone grafts are commonly used to enhance bone fusion and to provide stability. In practice, autologous bone graft, such as, iliac bone crest is most often adopted. In thoracolumbar vertebral surgery, the ribs are often dissected and may be an alternative choice for bone graft besides iliac bone. However, the biomechanical efficacy of rib bone graft used in thoracolumbar anterior bone fusion was not reported in literature. The purpose of this study was to use a finite element model to evaluate the effects of using iliac bone; one rib or two ribs bone graft, with and without instrumentation in thoracolumbar vertebral bone graft surgery. Fifty-four transverse plane CT scan images were obtained at 3 mm intervals and used to create a T10 to L2 five-segment, three-dimensional finite element model. Only the T12-L1 motion segment was used for this study. The intervertebral disc in the segment was removed and anterior bone graft surgery was simulated. The bone fusion was assumed for all models, therefore, the iliac bone and rib bone were assigned with the same material property. All interfaces were assumed to be bond with no micromotion. Based on the stress results, we found that when only one rib bone was used, the stress in the graft was higher than that of the iliac bone graft and the two ribs bone graft conditions and spinal instrumentation must be applied. This implies that early collapse may occur when only one rib bone graft was applied. But if spinal instrumentation was applied, the stress on the one rib bone graft was similar with the two ribs bone graft and iliac crest bone graft. The stress distributions for the iliac bone graft and the two ribs bone graft were similar whether using spinal instrumentation or not. Therefore, two ribs bone graft may be an acceptable alternative besides iliac bone graft if fully bone fusion is established. If bone fusion is not established, then iliac bone graft may still be a safer choice than rib bone graft.
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