Knop C, Lange U, Bastian L, Blauth M
Unfallchirurgische Universitätsklinik, Leopold-Franzens-Universität Innsbruck, Landeskrankenhaus, Anichstrasse 35, 6020 Innsbruck, Osterreich.
Unfallchirurg. 2001 Oct;104(10):984-97. doi: 10.1007/s001130170041.
The authors present a new implant for vertebral body replacement in the thoracic and lumbar spine. The titanium implant is designated for reconstruction of the anterior column in injury, posttraumatic kyphosis or tumor of the thoracolumbar spine. The instrumentation has to be supplemented by a stabilizing implant. After positioning, the implant is distracted in situ, through which best contact to adjacent end-plates and 3-dimensional stability should be provided. The possibility of secondary dislocation or loss of correction should thereby be minimized.
We investigated the biomechanical 3-dimensional stability in vitro, using Synex in combination with an anteriorly (Ventrofix) or a posteriorly (USS) stabilizing implant. The differences between both stabilizing implants were to be determined. Synex was compared with the "Harms titanium mesh cage" (MOSS) as vertebral body replacement.
In a 3-dimensional spinal loading simulator, we determined the bisegmental (T12-L2) neutral zone (NZ), elastic zone (EZ), and range of motion (ROM) of 12 human cadaveric spines. After corpectomy of L1 we tested 4 groups of implant combinations: USS/Synex, USS/MOSS, Ventrofix/Synex, Ventrofix/MOSS. We analyzed the differences between each of the instrumentations as well as differences compared to the intact spine.
In most directions, significantly higher stability was achieved with USS, compared with Ventrofix and the intact specimen. For axial rotation, with no instrumentation the stability of the intact spine was restored. With Synex a significantly higher stability was noted for extension, lateral bending, and axial rotation in comparison with the Harms cage. A tendency towards more stability for flexion was additionally observed with Synex. When using MOSS in combination with USS, it was necessary to perform a third operative step for induction of intervertebral compression via the posterior fixator.
The posterior fixation was found to offer superior stability compared to the anterior one. Synex was at least comparable to MOSS for suspensory replacement of the vertebral body in the thoracolumbar spine. The evidence of higher biomechanical stability with Synex leads to the probability of a higher rigidity in vivo. Due to the distractability of Synex, a better intervertebral compression was achieved. Therefore, an additional tightening of the posterior fixator after insertion of Synex was not necessary, in contrast to the Harms cage.
作者介绍了一种用于胸腰椎椎体置换的新型植入物。该钛植入物用于胸腰椎损伤、创伤后脊柱后凸或肿瘤时前柱的重建。该器械必须辅以稳定植入物。定位后，植入物在原位撑开，借此应能与相邻终板实现最佳接触并提供三维稳定性。从而应将继发性脱位或矫正丢失的可能性降至最低。
我们使用Synex联合前路（Ventrofix）或后路（USS）稳定植入物，在体外研究其生物力学三维稳定性。要确定两种稳定植入物之间的差异。将Synex与“哈姆斯钛网笼”（MOSS）作为椎体置换物进行比较。
在三维脊柱加载模拟器中，我们测定了12具人类尸体脊柱的双节段（T12-L2）中立区（NZ）、弹性区（EZ）和活动范围（ROM）。在切除L1椎体后，我们测试了4组植入物组合：USS/Synex、USS/MOSS、Ventrofix/Synex、Ventrofix/MOSS。我们分析了每种器械之间的差异以及与完整脊柱相比的差异。
在大多数方向上，与Ventrofix和完整标本相比，USS实现了显著更高的稳定性。对于轴向旋转，在未使用器械的情况下，完整脊柱的稳定性得以恢复。与哈姆斯笼相比，使用Synex时在伸展、侧弯和轴向旋转方面观察到显著更高的稳定性。使用Synex时还额外观察到在屈曲方面有更稳定的趋势。当将MOSS与USS联合使用时，有必要通过后路固定器进行第三步手术以诱导椎间压缩。
发现后路固定比前路固定具有更高的稳定性。在胸腰椎椎体的悬吊式置换中，Synex至少与MOSS相当。Synex具有更高生物力学稳定性的证据表明其在体内具有更高刚性的可能性。由于Synex可撑开，实现了更好的椎间压缩。因此，与哈姆斯笼不同，在植入Synex后无需额外收紧后路固定器。
