Anterior cervical discectomy with fusion is a common surgical treatment that can relieve patients suffering from cervical spondylosis. This surgery is most commonly performed with the use of a cervical cage. One serious complication of the fusion cages commercially available in the market is subsidence of the cage with loss of the normal alignment of the spine and recurrent pain. This work presents the proof-of-concept of a fusion cage made of a graded porous titanium with microarchitecture minimizing the risk of subsidence associated with fully-solid implants. The optimized properties of the porous implant are obtained through a scheme combining multiscale mechanics and density-based topology optimization. Asymptotic homogenization is used to capture the effective properties of the porous material, which uses a tetrahedron based cell as building block. The stress levels and normal strains obtained under various loading conditions on the C7 superior surface of the vertebrae are used as indicators of subsidence. The results suggest a reduced risk of subsidence for the optimized implant versus the fully-solid implant. Under the most severe condition of combined loading, a collective improvement of the average von Mises stress up to 14% can be observed on the posterior, left, and right lateral regions of the C7 superior surface. Similarly, for the average normal strain, the optimized cage exhibits a more favourable distribution with a top gain of 21.7% at given locations.

颈椎前路椎间盘切除术融合术是一种常见的外科手术治疗方法，可以缓解患有颈椎病的患者。该手术最通常是通过使用子宫颈笼进行的。市场上可买到的融合器的一个严重的并发症是该融合器的下沉，脊柱的正常对准丧失和复发性疼痛。这项工作提出了一种由渐变多孔钛制成的融合笼的概念验证，该融合笼具有微结构，可将与全固态植入物相关的下陷风险降至最低。通过将多尺度力学和基于密度的拓扑优化相结合的方案，可以获得多孔植入物的最佳性能。渐近均质化用于捕获多孔材料的有效特性，它使用基于四面体的单元作为构建块。椎骨C7上表面在各种载荷条件下获得的应力水平和法向应变被用作下沉指标。结果表明，与全固态种植体相比，优化种植体的下陷风险降低。在最严重的组合载荷条件下，可以在C7上表面的后，左和右外侧区域观察到平均von Mises应力的集体提高，最高可达14％。同样，对于平均法向应变，优化后的笼子显示出更有利的分布，在给定位置的最高增益为21.7％。结果表明，与全固态种植体相比，优化种植体的下陷风险降低。在最严重的组合载荷条件下，可以在C7上表面的后，左和右外侧区域观察到平均von Mises应力的集体提高，最高可达14％。同样，对于平均法向应变，优化后的笼子显示出更有利的分布，在给定位置的最高增益为21.7％。结果表明，与全固态种植体相比，优化种植体的下陷风险降低。在最严重的组合载荷条件下，可以在C7上表面的后，左和右外侧区域观察到平均von Mises应力的集体提高，最高可达14％。同样，对于平均法向应变，优化后的笼子显示出更有利的分布，在给定位置的最高增益为21.7％。