Annu Int Conf IEEE Eng Med Biol Soc. 2022 Jul;2022:3313-3317. doi: 10.1109/EMBC48229.2022.9871068.
Loosening of pedicle screws after spinal fusion surgery can prevent the desired fusion between vertebrae and may be a reason for revision surgery. Especially in osteoporotic bone, toggling of pedicle screws is a common problem that compromises the fixation strength of these screws and can lead to loosening or axial pull-out of the screw. In this study, we explore the use of an in-pedicle expandable anchor that shapes to the pedicle to increase the toggling resistance of the anchor by increasing the contact area between the anchor and the dense cortical bone of the pedicle. A scaled-up, two-dimensional prototype was designed. The prototype consists of a bolt and ten stainless steel wedges that expand by tensioning the bolt. During the expansion, the wedges are required to compress the cancellous bone. Based on the first preliminary experiment, it was found that the expansion of the wedges resulted in successful compression of 5 PCF cancellous bone phantom (Sawbones). This preliminary study shows that an expandable in-pedicle anchor could be a feasible option to increase the toggling resistance of spinal bone anchors, especially in osteoporotic bone. Clinical Relevance- Toggling of pedicle screws is a major cause of screw loosening. In this preliminary study, the use of an in-pedicle expandable anchor to increase the toggling resistance of spinal bone anchors is explored.
脊柱融合手术后椎弓根螺钉松动会阻碍预期的椎体融合，可能是翻修手术的原因。特别是在骨质疏松的骨骼中，椎弓根螺钉的摆动是一个常见的问题，会降低这些螺钉的固定强度，并导致螺钉松动或轴向拔出。在这项研究中，我们探索了使用一种可在椎体内扩张的锚定物，该锚定物可根据椎弓根的形状来增加锚定物的摆动阻力，从而增加锚定物与椎弓根致密皮质骨之间的接触面积。设计了一个按比例放大的二维原型。该原型由一个螺栓和十个不锈钢楔形物组成，通过拉紧螺栓来实现扩张。在扩张过程中，楔形物需要压缩松质骨。根据第一次初步实验，发现楔形物的扩张成功地压缩了 5 个 PCF 松质骨模型（Sawbones）。这项初步研究表明，可在椎体内扩张的锚定物可能是增加脊柱骨锚定物摆动阻力的一种可行选择，特别是在骨质疏松的骨骼中。临床意义-椎弓根螺钉的摆动是螺钉松动的主要原因。在这项初步研究中，探索了使用可在椎体内扩张的锚定物来增加脊柱骨锚定物的摆动阻力。
