Lin Maohua, Paul Rudy, Shapiro Stephen Z, Doulgeris James, O'Connor Timothy E, Tsai Chi-Tay, Vrionis Frank D
Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, USA.
Department of Neurosurgery, Marcus Neuroscience Institute, Boca Raton Regional Hospital, Boca Raton, FL, USA.
Asian Spine J. 2022 Oct;16(5):615-624. doi: 10.31616/asj.2021.0424. Epub 2022 Mar 11.
This study compares four cervical endplate removal procedures, validated by finite element models.
To characterize the effect of biomechanical strength and increased contact area on the maximum von Mises stress, migration, and subsidence between the cancellous bone, endplate, and implanted cage.
Anterior cervical discectomy and fusion (ACDF) has been widely used for treating patients with degenerative spondylosis. However, no direct correlations have been drawn that incorporate the impact of the contact area between the cage and the vertebra/endplate.
Model 1 (M1) was an intact C2C6 model with a 0.5 mm endplate. In model 2 (M2), a cage was implanted after removal of the C4-C5 and C5-C6 discs with preservation of the osseous endplate. In model 3 (M3), 1 mm of the osseous endplate was removed at the upper endplate. Model 4 (M4) resembles M3, except that 3 mm of the osseous endplate was removed.
The range of motion (ROM) at C2C6 in the M2-M4 models was reduced by at least 9º compared to the M1 model. The von Mises stress results in the C2C3 and C3C4 interbody discs were significantly smaller in the M1 model and slightly increased in the M2-M3 and M3-M4 models. Migration and subsidence decreased from the M2-M3 model, whereas further endplate removal increased the migration and subsidence as shown in the transition from M3 to M4.
The M3 model had the least subsidence and migration. The ROM was higher in the M3 model than the M2 and M4 models. Endplate preparation created small stress differences in the healthy intervertebral discs above the ACDF site. A 1 mm embedding depth created the best balance of mechanical strength and contact area, resulting in the most favorable stability of the construct.
本研究比较了四种经有限元模型验证的颈椎终板切除术。
描述生物力学强度和接触面积增加对松质骨、终板和植入椎间融合器之间的最大冯·米塞斯应力、移位和沉降的影响。
颈椎前路椎间盘切除融合术（ACDF）已广泛用于治疗退行性脊柱病患者。然而，尚未得出包含椎间融合器与椎体/终板之间接触面积影响的直接相关性。
模型1（M1）是具有0.5毫米终板的完整C2 - C6模型。在模型2（M2）中，切除C4 - C5和C5 - C6椎间盘并保留骨性终板后植入椎间融合器。在模型3（M3）中，在上终板处切除1毫米的骨性终板。模型4（M4）与M3相似，只是切除了3毫米的骨性终板。
与M1模型相比，M2 - M4模型中C2 - C6的活动范围（ROM）至少减少了9°。M1模型中C2 - C3和C3 - C4椎间盘中的冯·米塞斯应力结果明显较小，而在M2 - M3和M3 - M4模型中略有增加。从M2 - M3模型开始，移位和沉降减少，而如从M3到M4的转变所示，进一步切除终板会增加移位和沉降。
M3模型的沉降和移位最少。M3模型的ROM高于M2和M4模型。终板准备在ACDF部位上方的健康椎间盘中产生了微小的应力差异。1毫米的嵌入深度在机械强度和接触面积之间创造了最佳平衡，从而使结构具有最有利的稳定性。
