BACKGROUND Three-dimensionally printed titanium (3D-Ti) cages can be divided into 2 types: window-type cages, which have a void for bone graft, and non-window-type cages without a void. Few studies have investigated the necessity of a void for bone graft in fusion surgery. Therefore, the present study assessed the clinical and radiographic outcomes of window and non-window-type 3D-Ti cages in single-level posterior lumbar interbody fusion. METHODS A total of 70 patients were randomly assigned to receive either a window or non-window cage; 61 patients (87%) completed final follow-up (32 from the window cage group, 29 from the non-window cage group). Radiographic outcomes, including fusion rates, subsidence, and intra-cage osseointegration patterns, were assessed. Intra-cage osseointegration was measured using the intra-cage bridging bone score for the window cage group and the surface osseointegration ratio score for the non-window cage group. Additionally, we looked for the presence of the trabecular bone remodeling (TBR) sign on computed tomography (CT) images. RESULTS Of the 61 patients, 58 achieved interbody fusion, resulting in a 95.1% fusion rate. The fusion rate in the non-window cage group was comparable to, and not significantly different from, that in the window cage group (96.6% and 93.8%, p > 0.99). The subsidence rate showed no significant difference between the window and non-window cage groups (15.6% and 3.4%, respectively; p = 0.262). The intra-cage osseointegration scores showed a significant difference between the groups (p = 0.007), with the non-window cage group having a higher proportion of cases with a score of 4 compared with the window cage group. The TBR sign was observed in 87.9% of patients who achieved interbody fusion, with a higher rate in the non-window cage group across the entire cohort although the difference was not significant (89.7% versus 78.1%, p = 0.385). CONCLUSIONS Non-window-type 3D-Ti cages showed equivalent clinical outcomes compared with window-type cages and comparable interbody fusion rates. These results suggest that the potential advantages of 3D-Ti cages could be optimized in the absence of a void for bone graft by providing a larger contact surface for osseointegration. LEVEL OF EVIDENCE Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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非窗口型 3D 打印多孔钛笼在后腰椎间融合中的可行性：随机对照多中心试验。


背景技术三维打印钛(3D-Ti)融合器可分为两种类型：窗式融合器，其具有用于骨移植的空隙；以及非窗式融合器，没有空隙。很少有研究调查融合手术中骨移植空隙的必要性。因此，本研究评估了单节段后路腰椎椎间融合术中窗型和非窗型 3D-Ti 融合器的临床和影像学结果。方法 共有 70 名患者被随机分配接受窗笼或非窗笼； 61 例患者 (87%) 完成最终随访（窗笼组 32 例，非窗笼组 29 例）。评估了放射学结果，包括融合率、沉降和笼内骨整合模式。使用窗笼组的笼内桥接骨评分和非窗笼组的表面骨整合率评分来测量笼内骨整合。此外，我们还在计算机断层扫描 (CT) 图像上寻找骨小梁重塑 (TBR) 标志的存在。结果 61例患者中，58例实现椎间融合，融合率95.1%。无窗笼组的融合率与窗笼组相当，但没有显着差异（96.6% 和 93.8%，p > 0.99）。窗笼组和非窗笼组的沉降率没有显着差异（分别为 15.6% 和 3.4%；p = 0.262）。各组之间的笼内骨整合评分存在显着差异（p = 0.007），与窗笼组相比，非窗笼组评分为 4 分的病例比例更高。 87 例观察到 TBR 征象。9% 的患者实现椎间融合，整个队列中非窗笼组的比例较高，但差异并不显着（89.7% 与 78.1%，p = 0.385）。结论 与窗式融合器相比，非窗式 3D-Ti 融合器显示出相同的临床结果和相似的椎间融合率。这些结果表明，在没有骨移植空隙的情况下，通过为骨整合提供更大的接触表面，可以优化 3D-Ti 融合器的潜在优势。证据级别 治疗级别 II。有关证据级别的完整描述，请参阅作者须知。