Germaneau Arnaud, Vendeuvre Tanguy, Delmotte Alexandre, D'Houtaud Samuel, Brèque Cyril, Petureau Louis, Doumalin Pascal, Dupré Jean-Christophe, Brémand Fabrice, Maxy Philippe, Richer Jean-Pierre, Rigoard Philippe
Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; Spine & Neuromodulation Functional Unit, Department of Neurosurgery, CHU Poitiers, PRISMATICS Lab, Poitiers, France.
Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; Spine & Neuromodulation Functional Unit, Department of Neurosurgery, CHU Poitiers, PRISMATICS Lab, Poitiers, France.
Clin Biomech (Bristol). 2020 Dec;80:105173. doi: 10.1016/j.clinbiomech.2020.105173. Epub 2020 Sep 12.
Occipito-cervical fusion can be necessary in case of cranio-cervical junction instability. Proximal stabilisation is usually ensured by bi-cortical occipital screws implanted through one median or two lateral occipital plate(s). Bone thickness variability as well as the proximity of vasculo-nervous elements can induce substantial morbidity. The choice of site and implant type remains difficult for surgeons and is often empirically based. Given this challenge, implants with smaller pitch to increase bone interfacing are being developed, as is a surgical technique consisting in inverted occipital hook clamps, a potential alternative to plate/screws association. We present here a biomechanical comparison of the different occipito-cervical fusion devices.
We have developed a 3D mark tracking technique to measure experimental mechanical data on implants and occipital bone. Biomechanical tests were performed to study the mechanical stiffness of the occipito-cervical instrumentation on human skulls. Four occipital implant systems were analysed: lateral plates+large pitch screws, lateral plates+hooks, lateral plates+small pitch screws and median plate+small pitch screws. Mechanical responses were analysed using 3D displacement field measurements from optical methods and compared with an analytical model.
Paradoxical mechanical responses were observed among the four types of fixations. Lateral plates+small pitch screws appear to show the best accordance of displacement field between bone/implant/system interface providing higher stiffness and an average maximum moment around 50 N.m before fracture.
Stability of occipito-cervical fixation depends not only on the site of screws implantation and occipital bone thickness but is also directly influenced by the type of occipital implant.
颅颈交界区不稳定时可能需要进行枕颈融合术。近端稳定通常通过经一块枕骨正中板或两块枕骨外侧板植入的双皮质枕骨螺钉来确保。骨厚度的变异性以及血管神经结构的临近可能导致严重的并发症。对于外科医生来说，手术部位和植入物类型的选择仍然很困难，而且往往基于经验。面对这一挑战，正在研发螺距更小以增加与骨接触的植入物，还有一种由枕骨倒钩夹组成的手术技术，这可能是板/螺钉组合的一种替代方案。我们在此展示不同枕颈融合装置的生物力学比较。
我们开发了一种三维标记跟踪技术，以测量植入物和枕骨上的实验力学数据。进行生物力学测试以研究人体颅骨上枕颈器械的力学刚度。分析了四种枕骨植入系统：外侧板 + 大螺距螺钉、外侧板 + 钩、外侧板 + 小螺距螺钉和正中板 + 小螺距螺钉。使用光学方法测量的三维位移场分析力学响应，并与分析模型进行比较。
在四种固定类型中观察到了矛盾的力学响应。外侧板 + 小螺距螺钉似乎在骨/植入物/系统界面之间的位移场一致性方面表现最佳，提供了更高的刚度，并且在骨折前平均最大力矩约为50 N·m。
枕颈固定的稳定性不仅取决于螺钉植入部位和枕骨厚度，还直接受枕骨植入物类型的影响。
