Faizan Ahmad, Kiapour Ali, Kiapour Ata M, Goel Vijay K
*Custom Spine Inc., Parsippany, NJ †Departments of Bioengineering and Orthopaedic Surgery, Engineering Center for Orthopaedic Research Excellence (E-CORE), Colleges of Engineering and Medicine, University of Toledo, Toledo, OH.
J Spinal Disord Tech. 2014 Jun;27(4):E118-27. doi: 10.1097/BSD.0b013e3182a11478.
A biomechanical finite element modeling study of the human lumbar spine.
To evaluate the effects of a transforaminal interbody device's footprint on lumbar spine biomechanics to further examine the potential subtle biomechanical differences not captured in previous studies.
In recent years, the evolution of interbody fusion devices has provided the surgeons with a multitude of options. An articulating transforaminal lumbar interbody fusion (TLIF) device is developed to overcome the surgical challenges associated with insertion of a large footprint interbody device through a small incision.
A finite element model of the L3-S1 lumbar segment was modified to simulate replacement of various TLIF constructs with different cage designs including an articulating vertebral interbody (AVID) TLIF device and a generic TLIF device placed in different configurations. The instrumented models were subjected to a 400 N follower load along with a 10 N m bending moment at different physiological planes. The kinematics, loads, and stresses were compared among various models.
Simulated cage designs provided similar kinematical stability within the treated segments. However, the articulating and double TLIF implants allowed for better load sharing through the anterior column. These implants resulted in lower endplate and pedicle screw stresses and in more homogenous stress distribution across the peripheral region of the endplate.
An articulating, large footprint, peripherally placed TLIF device affords substantial biomechanical advantages. This device may be able to reduce the incidence of subsidence because of its ability to reduce and distribute the endplate stresses in the stronger peripheral region. It may also reduce the posterior hardware failure incidence owing to its ability to reduce the screw stresses as compared with traditional TLIF. Although double TLIF has been demonstrated to have similar biomechanical advantages as the AVID, complications associated with double TLIF (ie, larger surgical incision, longer surgical procedure, placement and alignment challenges) support AVID as a better optimized alternative.
一项关于人体腰椎的生物力学有限元建模研究。
评估经椎间孔椎间融合器的接触面积对腰椎生物力学的影响，以进一步研究以往研究未发现的潜在细微生物力学差异。
近年来，椎间融合器不断发展，为外科医生提供了多种选择。一种可活动的经椎间孔腰椎椎间融合（TLIF）装置被研发出来，以克服通过小切口植入大接触面积椎间融合器所带来的手术挑战。
对L3 - S1腰椎节段的有限元模型进行修改，以模拟用不同笼式设计替换各种TLIF结构，包括可活动椎间融合（AVID）TLIF装置和以不同配置放置的普通TLIF装置。对植入器械的模型在不同生理平面施加400 N的跟随载荷以及10 N·m的弯矩。比较各种模型之间的运动学、载荷和应力。
模拟的笼式设计在治疗节段内提供了相似的运动稳定性。然而，可活动和双TLIF植入物能够通过前柱实现更好的载荷分担。这些植入物使终板和椎弓根螺钉应力降低，并且终板周边区域的应力分布更均匀。
一种可活动的、大接触面积、周边放置的TLIF装置具有显著的生物力学优势。由于该装置能够在更强的周边区域减少并分布终板应力，它可能能够降低下沉发生率。与传统TLIF相比，它还可能降低后部硬件故障发生率，因为其能够降低螺钉应力。尽管双TLIF已被证明具有与AVID相似的生物力学优势，但与双TLIF相关的并发症（即更大的手术切口、更长的手术时间、放置和对齐挑战）支持AVID作为更好的优化选择。
