Junhua Ye, Qinguo Huang, Qiang Zhou, Hong Li, Lin Peng, Songtao Qi, Yuntao Lu
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引用次数: 0
Abstract
Objective: Recent studies indicate that 3 morphological types of atlanto-occipital joint (AOJ) exist in the craniovertebral junction and are associated with type II basilar invagination (BI) and atlanto-occipital instability. However, the actual biomechanical effects remain unclear. This study aims to investigate biomechanical differences among AOJ types I, II, and III, and provide further evidence of atlanto-occipital instability in type II BI.
Methods: Models of bilateral AOJ containing various AOJ types were created, including I-I, I-II, II-II, II-III, and III-III models, with increasing AOJ dysplasia across models. Then, 1.5 Nm torque simulated cervical motions. The range of motion (ROM), ligament and joint stress, and basion-dental interval (BDI) were analyzed.
Results: The C0-1 ROM and accompanying rotational ROM increased progressively from model I-I to model III-III, with the ROM of model III-III showing increases between 27.3% and 123.8% indicating ultra-mobility and instability. In contrast, the C1-2 ROM changes were minimal. Meanwhile, the stress distribution pattern was disrupted; in particular, the C1 superior facet stress was concentrated centrally and decreased substantially across the models. The stress on the C0-1 capsule ligament decreased during cervical flexion and increased during bending and rotating loading. In addition, BDI gradually decreased across the models. Further analysis revealed that the dens showed an increase of 110.1% superiorly and 11.4% posteriorly, indicating an increased risk of spinal cord impingement.
Conclusion: Progressive AOJ incongruity critically disrupts supportive tissue loading, enabling incremental atlanto-occipital instability. AOJ dysplasia plays a key biomechanical role in the pathogenesis of type II BI.
目的:最近的研究表明,在颅椎交界处存在三种形态的寰枕关节(AOJ),它们与 II 型基底内陷(BI)和寰枕不稳定性有关。然而,实际的生物力学影响仍不清楚。本研究旨在调查 AOJ I、II 和 III 型之间的生物力学差异,并为 II 型 BI 中的寰枕不稳定性提供进一步证据:方法:建立了包含不同AOJ类型的双侧AOJ模型,包括I-I型、I-II型、II-II型、II-III型和III-III型模型,不同模型的AOJ发育不良程度不同。然后,用 1.5 牛米扭矩模拟颈椎运动。对运动范围(ROM)、韧带和关节应力以及基底牙间隙(BDI)进行了分析:从模型 I 至模型 III-III,C0-1 的活动范围和伴随的旋转活动范围逐渐增加,模型 III-III 的活动范围增加了 27.3% 至 123.8%,表明活动范围过大和不稳定。相比之下,C1-2 的 ROM 变化很小。同时,应力分布模式也被打乱,尤其是C1上切面应力集中在中央位置,并且在不同模型中大幅下降。C0-1 囊韧带的应力在颈椎屈曲时减少,而在弯曲和旋转加载时增加。此外,BDI 在各模型中逐渐减小。进一步的分析表明,椎弓根向上增加了110.1%,向后增加了11.4%,这表明脊髓撞击的风险增加了:结论:渐进性 AOJ 不协调严重破坏了支持性组织负荷,导致寰枕不稳定性不断增加。AOJ发育不良在II型BI的发病机制中起着关键的生物力学作用。