Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu, China.
Department of Orthopedics Surgery, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, China.
J Orthop Surg Res. 2024 Oct 30;19(1):705. doi: 10.1186/s13018-024-05218-5.
Artificial cervical disc replacement (ACDR) is a widely accepted surgical procedure in the treatment of cervical radiculopathy and myelopathy. However, some research suggests that ACDR may redistribute more load onto the facet joints, potentially leading to postoperative axial pain in certain patients. Earlier studies have indicated that facet tropism is prevalent in the lower cervical spine and can significantly increase facet joint pressure. The present study aims to investigate the changes in the biomechanical environment of the cervical spine after ACDR using different prosthese when facet tropism is present.
A C2-C7 cervical spine finite element model was created. Symmetrical, moderate asymmetrical (7 degrees tropism), and severe asymmetrical (14 degrees tropism) models were created at the C5/C6 level by adjusting the left-side facet. C5/C6 ACDR with Prestige LP, Prodisc-C vivo, and Mobi-C were simulated in all models. A 75 N follower load and 1 N⋅m moment was applied to initiate flexion, extension, lateral bending, and axial rotation, and the range of motions (ROMs), facet contact forces(FCFs), and facet capsule stress were recorded.
In the presence of facet tropism, all ACDR models exhibited significantly higher FCFs and facet capsule stress compared to the intact model. In the asymmetric model, FCFs on the right side were significantly increased in neutral position, extension, left bending and right rotation, and on both sides in right bending and left rotation compared to the symmetric model. All ACDR model in the presence of facet tropism, exhibited significantly higher facet capsule stresses at all positions compared to the symmetric model. The stress distribution on the facet surface and the capsule ligament in the asymmetrical models was different from that in the symmetrical model.
The existence of facet tropism could considerably increase FCFs and facet capsule stress after ACDR with Prestige-LP, Prodisc-C Vivo, and Mobi-C. None of the three different designs of implants were able to effectively protect the facet joints in the presence of facet tropism. Research into designing new implants may be needed to improve this situation. Clinical trials are needed to validate the impact of facet tropism.
人工颈椎间盘置换术（ACDR）是治疗颈椎神经根病和颈椎病的一种广泛接受的手术方法。然而，一些研究表明，ACDR 可能会将更多的负荷重新分配到关节突关节上，从而导致某些患者术后出现轴向疼痛。早期的研究表明，关节突关节倾斜在颈椎下部很常见，并且会显著增加关节突关节的压力。本研究旨在探讨在存在关节突关节倾斜的情况下，使用不同假体对颈椎生物力学环境的变化。
建立了 C2-C7 颈椎有限元模型。通过调整左侧关节突，在 C5/C6 水平创建了对称、中度不对称（7 度倾斜）和严重不对称（14 度倾斜）模型。在所有模型中，模拟了 C5/C6 的 Prestige LP、Prodisc-C vivo 和 Mobi-C ACDR。施加 75N 跟随力和 1N·m 力矩，以启动屈伸、侧屈和轴向旋转，并记录活动范围（ROM）、关节突接触力（FCF）和关节突囊应力。
在存在关节突关节倾斜的情况下，所有 ACDR 模型的 FCF 和关节突囊应力均明显高于完整模型。在不对称模型中，中立位、伸展位、左侧弯曲位和右侧旋转位右侧 FCF 明显增加，右侧弯曲位和左侧旋转位双侧 FCF 明显增加与对称模型相比。与对称模型相比，存在关节突关节倾斜的所有 ACDR 模型在所有位置的关节突囊应力均显著升高。不对称模型中关节突表面和囊韧带的应力分布与对称模型不同。
存在关节突关节倾斜会显著增加 Prestige-LP、Prodisc-C Vivo 和 Mobi-C 行 ACDR 后的 FCF 和关节突囊应力。三种不同设计的植入物都不能有效地保护存在关节突关节倾斜时的关节突关节。可能需要研究设计新的植入物来改善这种情况。需要进行临床试验来验证关节突关节倾斜的影响。
