寰枢椎融合器内固定一体化的解剖学和生物力学研究

Atlantoaxial dislocation is a common cranial-cervical deformity with high morbidity and mortality due to inappropriate treatment. We’ve proposed a new clinical classification of atlantoaxial dislocation based on its clinical manifestations, namely reducible atlantoaxial dislocation(RAAD), irreducible atlantoaxial dislocation(IAAD), and fixed atlantoaxial dislocation(FAAD). The latter two types should be treated through transoral approach for release, reduction, decompression and TARP fixation. But there are defects in TARP surgery. The TARP system is a complicated system with high technical requirement for fixation. The would of the pharynx wall will sustain considerable strain after TARP implantation. There is no effective support for load sharing between the atlantoaxial joints. In our prophase research, we have found that it is possible for placing a support cage between the atlantoaxial joint. Meanwhile, the converse atlas mass screw and axis pedicle screw are approximating to maturity in technology. Therefore, we aim to design a new implantation with the integration of a cage and fixation system. We believe that this new integration of a cage and fixation system will decrease the occurrence of vascular and neural complication. We will measure the anatomic parameter of atlantoaxial specimens and the CT scans of the cervical spine. Mechanical properties of the new fixation system will be verified by biomechanical study and finite element analysis. And finally, we aim to modify the stability of the internal fixation and improve the load sharing for the atlantoaxial joints. We believe that this new integration of a cage and fixation system will enhance the curative effect of atlantoaxial dislocation.

寰枢椎脱位是常见的枕颈畸形，治疗不当时死亡率和致残率很高。我们提出的临床分型，将寰枢椎脱位分为可复性、难复性和不可复性寰枢椎脱位。后两者类型的手术治疗，均需要经口咽入路行松解复位寰枢内固定术（TARP），但存在内固定方式难度较高，口咽部伤口缝合张力大，寰枢关节间的植骨无可靠的支撑等缺点。我们前期研究已证实寰枢椎侧块间具有置入融合器的可行性，同时，我们提出的逆向寰椎、枢椎螺钉内固定技术已趋于成熟。因此我们拟设计新型一体化寰枢椎融合器内固定系统，旨在优化寰枢椎固定的稳定性，实现与融合器植骨良好的载荷共享，降低内固定切迹，降低血管、神经损伤概率。本项目拟通过对寰枢椎标本及正常人群颈椎CT加三维重建的解剖学研究，设计出适合国人的一体化寰枢椎融合器内固定系统，并对该内固定系统进行生物力学研究和有限元分析，以提高寰枢椎脱位的临床救治疗效。