Dick J C, Brodke D S, Zdeblick T A, Bartel B D, Kunz D N, Rapoff A J
Orthopaedic Consultants, PA, Minneapolis, Minnesota, USA.
Spine (Phila Pa 1976). 1997 Apr 1;22(7):744-50. doi: 10.1097/00007632-199704010-00005.
To evaluate the fatigue strength and stiffness of four anterior thoracolumbar fixation devices using a corpectomy model without load-sharing bone graft to test the devices under the worst case scenario of instability.
To gain a more thorough understanding of the biomechanical qualities of anterior fixation devices to improve clinical application and design.
For many surgeons, the anterior approach has become the treatment of choice for patients with compression of the spinal cord, whether it is caused by trauma, tumor, or infection. When stabilization is needed, anterior fixation devices have been advocated for many years to avoid the additional approach required for posterior fixation. Many of these devices, however, have an unacceptably high rate of hardware failure. Recently, several new devices for anterior fixation have been marketed with purported advantages in fatigue life and ease of use.
Four implants, the Synthes Anterior Thoracolumbar Locking Plate, the Kaneda device, a Texas Scottish Rite Hospital anterior construct, and the Z-Plate were attached to vertebral models and tested for stiffness in multiple planes on a modified Materials Testing System machine. They then were fatigued to failure on an Instron testing machine.
The Anterior Thoracolumbar Locking Plate was the stiffest in axial compression, lateral flexion, and torsion. The Texas Scottish Rite Hospital anterior construct was the least stiff in flexion-extension, with no significant differences in the stiffness of the anterior thoracolumbar locking plate, that of the Kaneda device, and that of the Z-Plate. Fatigue life exceeded 80,000 cycles for the anterior thoracolumbar locking plate and averaged 26,472 cycles for the Z-Plate, 6915 cycles for the Teas Scottish Rite Hospital construct, and 4419 cycles for the Kaneda device.
The significantly greater fatigue life of the Anterior Thoracolumbar Locking Plate and the Z-Plate may predict a lower incidence of hardware failure than with previous anterior devices. This has been confirmed in preliminary clinical studies with the Z-Plate. Further clinical studies are needed to show if these lower failure rates will continue over a long-term period.
使用椎体切除模型，在不采用负载分担植骨的情况下，评估四种胸腰椎前路固定装置的疲劳强度和刚度，以在最不稳定的情况下测试这些装置。
更全面地了解前路固定装置的生物力学特性，以改进临床应用和设计。
对于许多外科医生而言，前路手术已成为脊髓受压患者的首选治疗方法，无论这种压迫是由创伤、肿瘤还是感染引起的。当需要稳定脊柱时，多年来一直提倡使用前路固定装置，以避免后路固定所需的额外手术入路。然而，许多此类装置的硬件故障率高得令人难以接受。最近，几种用于前路固定的新装置已投放市场，据称在疲劳寿命和易用性方面具有优势。
将四种植入物，即Synthes胸腰椎前路锁定钢板、Kaneda装置、德克萨斯州苏格兰礼医院前路构建物和Z-Plate，附着于椎体模型上，并在改良的材料测试系统机器上测试其在多个平面上的刚度。然后在Instron测试机上对它们进行疲劳测试直至失效。
胸腰椎前路锁定钢板在轴向压缩、侧方屈曲和扭转方面刚度最大。德克萨斯州苏格兰礼医院前路构建物在屈伸方面刚度最小，胸腰椎前路锁定钢板、Kaneda装置和Z-Plate的刚度无显著差异。胸腰椎前路锁定钢板的疲劳寿命超过80,000次循环，Z-Plate平均为26,472次循环，德克萨斯州苏格兰礼医院构建物为6915次循环，Kaneda装置为4419次循环。
胸腰椎前路锁定钢板和Z-Plate显著更长的疲劳寿命可能预示着与以往前路装置相比硬件故障发生率更低。这已在Z-Plate的初步临床研究中得到证实。需要进一步的临床研究来表明这些较低的故障率是否会长期持续。
