Department of Orthopedics, Xijing Hospital, The Air Force Medical University, Changlexi Road No. 127, Xi'an, Shaanxi Province, 710032, PR China; Department of Orthopedics, Air Force Hospital of Eastern Theater Command, Malujie Road No. 1, Nanjing, Jiangsu Province, 220001, PR China.
Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, PR China; National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, 300384, China.
Comput Biol Med. 2021 Jul;134:104477. doi: 10.1016/j.compbiomed.2021.104477. Epub 2021 May 12.
Different constructs are applied in revision surgery (RS) for adjacent segment disease (ASD) aiming to further decompress and fixate the affected segment(s) in two ways: replacing or preserving the primary implants. This study aimed to compare the biomechanical properties of four constructs with different configurations.
An T12-L5 finite element (FE) model was constructed and validated. Primary surgery was performed at L4-L5 and instrumented from L3 to L5. Thereafter, RS was undertook by decompressing L2-L3 and fixated with implant-replacing construct A, or implant-preserving construct B, C or D. Range of motion (ROM) and intervertebral disc pressure (IDP) were compared. Maximum von Mises stress on the rods between Construct A and B was evaluated.
An obvious reduction of ROM was observed when the FE model was instrumented with four constructs respectively. The overall changing characteristics of ROM were approximately identical among four constructs. The changing characteristic of IDP among four constructs was similar. The degree of IDP reduction of Construct B was comparable to Construct A, while that of Construct C was comparable to Construct D. Maximum von Mises stress on the rods between Construct A and B indicated that no stress concentration was recorded at the locking part of the connector rod.
The biomechanics of implant-preserving constructs were comparable to the traditional implant-replacing construct. The location of side-by-side connector could not affect the stability of Construct C and D. Construct B might be an optimal choice in RS for less dissection, less complication and more convenience in manipulation.
在翻修手术 (RS) 中，为了进一步减压和固定受影响的节段，采用了不同的结构，主要有两种方式：替换或保留原植入物。本研究旨在比较四种不同构型的构建物的生物力学性能。
构建并验证了 T12-L5 有限元 (FE) 模型。在 L4-L5 进行初次手术，并从 L3 到 L5 进行器械固定。此后，通过 L2-L3 减压并用植入物替换构建物 A 或植入物保留构建物 B、C 或 D 进行 RS。比较活动度 (ROM) 和椎间盘压力 (IDP)。评估构建物 A 和 B 之间的杆的最大 von Mises 应力。
当 FE 模型分别用四种构建物进行器械固定时，ROM 明显减小。四种构建物的 ROM 整体变化特征大致相同。四种构建物的 IDP 变化特征相似。构建物 B 的 IDP 降低程度与构建物 A 相当，而构建物 C 的 IDP 降低程度与构建物 D 相当。构建物 A 和 B 之间的杆的最大 von Mises 应力表明，在连接棒的锁定部分没有记录到应力集中。
保留植入物的构建物的生物力学性能与传统的植入物替换构建物相当。并排连接器的位置不会影响构建物 C 和 D 的稳定性。构建物 B 在 RS 中可能是一个最佳选择，因为它的手术操作更少、并发症更少、更方便。
