Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
State Key Lab of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
Comput Methods Programs Biomed. 2020 Jun;189:105352. doi: 10.1016/j.cmpb.2020.105352. Epub 2020 Jan 21.
To compare the biomechanical changes of adjacent segment degeneration (ASD) after one- or two-level anterior cervical discectomy and fusion (ACDF) versus cervical disc arthroplasty (CDA).
A three-dimensional finite element (FE) model of intact C2-C7 segments was constructed and validated. In the one-level surgery model, the cage with plate implant or Prestige LP cervical disc prosthesis were integrated at C5-C6 segment into the FE model; while in the two-level surgery model, the prostheses were integrated at both C4-C5 and C5-C6 segments into the FE model. A pure moment of 1.0 Nm combined with a follower load of 73.6 N were imposed on C2 to investigate the flexion-extension, lateral bending, and axial rotation of different segments in the FE model. The segmental range of motion (ROM) and intradiscal pressure of the surgery models were investigated and compared with the intact model.
In the one-level model of ACDF, the ROM at C5-C6 was decreased, the ROM and intradiscal pressure at C4-C5 and C6-C7 segments were increased. In the two-level model of ACDF, the ROM at C4-C5 and C5-C6 were decreased, the ROM and intradiscal pressure at C3-C4 and C6-C7 were increased. However, in both one- and two-level models of CDA, the ROM of surgery segments were preserved, avoiding the increase of the ROM and intradiscal pressure at the adjacent segments.
Abnormal ROM and intradiscal pressure at the adjacent segments may contribute to the higher risk of ASD after ACDF compared with CDA.
比较单节段和双节段颈椎前路椎间盘切除融合术（ACDF）与颈椎间盘置换术（CDA）后邻近节段退变（ASD）的生物力学变化。
构建并验证了 C2-C7 完整节段的三维有限元（FE）模型。在单节段手术模型中，将 cage 与板植入物或 Prestige LP 颈椎间盘假体整合到 C5-C6 节段的 FE 模型中；而在双节段手术模型中，将假体整合到 C4-C5 和 C5-C6 节段的 FE 模型中。在 C2 上施加 1.0 Nm 的纯力矩和 73.6 N 的跟随力，以研究 FE 模型中不同节段的屈伸、侧屈和轴向旋转。研究并比较了手术模型的节段活动范围（ROM）和椎间盘内压力与完整模型的差异。
在 ACDF 的单节段模型中，C5-C6 节段的 ROM 减小，C4-C5 和 C6-C7 节段的 ROM 和椎间盘内压力增加。在 ACDF 的双节段模型中，C4-C5 和 C5-C6 节段的 ROM 减小，C3-C4 和 C6-C7 节段的 ROM 和椎间盘内压力增加。然而，在 CDA 的单节段和双节段模型中，手术节段的 ROM 得到保留，避免了邻近节段 ROM 和椎间盘内压力的增加。
与 CDA 相比，ACDF 后邻近节段异常的 ROM 和椎间盘内压力可能导致 ASD 的风险更高。
