Liebsch Christian, Kocak Tugrul, Aleinikov Viktor, Kerimbayev Talgat, Akshulakov Serik, Jansen Jan Ulrich, Vogt Morten, Wilke Hans-Joachim
Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, Ulm University Medical Center, Ulm, Germany.
Department of Orthopedics, Ulm University, Ulm, Germany.
Front Bioeng Biotechnol. 2020 Jun 9;8:572. doi: 10.3389/fbioe.2020.00572. eCollection 2020.
Spinal tumors and unstable vertebral body fractures usually require surgical treatment including vertebral body replacement. Regarding primary stability, however, the best possible treatment depends on the spinal region. The purpose of this study was to evaluate the effects of instrumentation length and approach size on thoracic spinal stability including the entire rib cage. Six fresh frozen human thoracic spine specimens with intact rib cages (C7-L1) were loaded with pure moments of 5 Nm in flexion/extension, lateral bending, and axial rotation, while monitoring the relative motions of all spinal segments using optical motion tracking. The specimens were tested (1) in the intact condition, followed by testing after vertebral body replacement at T6 level using a unilateral approach combined with (2) long instrumentation (T4-T8) and (3) short instrumentation (T5-T7) as well as a bilateral approach combined with (4) long and (5) short instrumentation. Significant increases of the range of motion ( < 0.05) were found in the entire thoracic spine (T1-T12) using the bilateral approach and short instrumentation in primary flexion/extension and in secondary axial rotation during primary lateral bending compared to both conditions with long instrumentation, as well as in secondary lateral bending during primary axial rotation compared to unilateral approach and long instrumentation. Compared to the intact condition, the range of motion was significantly decreased using unilateral approach and long instrumentation in flexion extension and secondary lateral bending during primary axial rotation, as well as using bilateral approach and long instrumentation in lateral bending. On the segmental level, the range of motion was significantly increased at T4-T5 level in lateral bending using unilateral approach and short instrumentation and significantly decreased using bilateral approach and long instrumentation compared to their respective previous conditions. Regardless of the approach type, which did not affect thoracic spinal stability in the present study, short instrumentation overall shows sufficient primary stability in the mid-thoracic spine with intact rib cage, while creating considerably more instability compared to long instrumentation, potentially being of importance regarding long-term implant failure. Moreover, short instrumentation could affect adjacent segment disease due to increased motion at the upper segmental level.
脊柱肿瘤和不稳定椎体骨折通常需要包括椎体置换在内的手术治疗。然而，就初始稳定性而言，最佳治疗方案取决于脊柱区域。本研究的目的是评估内固定长度和手术入路范围对包括整个胸廓的胸段脊柱稳定性的影响。对六个带有完整胸廓（C7-L1）的新鲜冷冻人体胸段脊柱标本施加5 Nm的纯力矩，分别进行前屈/后伸、侧弯和轴向旋转，同时使用光学运动跟踪监测所有脊柱节段的相对运动。对标本进行如下测试：（1）在完整状态下测试，然后在T6水平使用单侧入路进行椎体置换后测试，分别结合（2）长节段内固定（T4-T8）和（3）短节段内固定（T5-T7），以及双侧入路结合（4）长节段和（5）短节段内固定。与长节段内固定的两种情况相比，在初次前屈/后伸以及初次侧弯时的二次轴向旋转中，使用双侧入路和短节段内固定时，整个胸段脊柱（T1-T12）的活动范围显著增加（P<0.05）；与单侧入路和长节段内固定相比，在初次轴向旋转时的二次侧弯中活动范围也显著增加。与完整状态相比，在屈曲/伸展以及初次轴向旋转时的二次侧弯中，使用单侧入路和长节段内固定时活动范围显著减小，在侧弯时使用双侧入路和长节段内固定时活动范围也显著减小。在节段水平上，与各自先前的情况相比，在侧弯时，使用单侧入路和短节段内固定，T4-T5节段的活动范围显著增加；使用双侧入路和长节段内固定，活动范围显著减小。在本研究中，手术入路类型不影响胸段脊柱稳定性，无论入路类型如何，短节段内固定总体上在胸廓完整的胸段脊柱中部显示出足够的初始稳定性，但与长节段内固定相比，会产生更多的不稳定性，这可能对长期植入物失效具有重要意义。此外，短节段内固定可能会因上段节段活动增加而影响相邻节段疾病。
