目的:提出了一种螺钉算法,并研究了五种不同的固定方法在C2椎弓根螺钉置入不可行时,对C2-3融合椎骨高椎动脉(VA)(HRVA)的解剖学可行性和临床效果。
方法:30例先天性C2-3融合手术患者,HRVA,包括寰枢椎脱位(AAD)。我们设计了一种替代螺钉植入C2-3融合椎骨的算法,包括C2椎弓根螺钉,具有in-out-in(通过VA凹槽)技术(in-out-in螺钉),面下螺钉,椎板螺钉,侧块螺钉,C3椎弓根螺钉。VA直径和位置,C2和C3椎弓根,优越的方面,融合层,和融合侧块尺寸评估了螺钉植入的适应症。植入失败,减少损失,通过计算机断层扫描研究植入物的放置准确性。
结果:共有5个VAs被鉴定为远处VAs;共有2个VAs被归类为闭塞性VAs。侧块和椎板的足够尺寸为螺钉植入提供了最广泛的适应症,而远处或闭塞的VA提供了最有限的进-进-进螺钉的适应症。五种替代方法的适应症从最窄到最宽如下:进-出-入螺钉,C3椎弓根螺钉,面下螺钉,椎板螺钉,侧向质量螺钉。经椎板螺钉和侧块螺钉增加了植入物失败的可能性。所有接受了进出螺钉的病人,C3椎弓根螺钉,和下平面螺钉实现了融合。精度从最低到最高,如下:C3椎弓根螺钉,侧块螺钉,进-出-入螺丝,面下螺钉,椎板螺钉.无椎板螺钉偏离。
结论:该算法被证明是在具有HRVA的C2-3融合椎骨的情况下选择螺钉的有价值的工具。下顶螺钉,拥有广泛的适应症,高融合率,和卓越的准确性,作为主要的首选替代方案。
OBJECTIVE: To propose a screw algorithm and investigate the anatomical feasibilities and clinical outcomes of five distinct fixation methods for C2-3 fused vertebra with high-ridding vertebral arteries (VA) (HRVA) when the C2 pedicle screw placement is unfeasible.
METHODS: Thirty surgical patients with congenital C2-3 fusion, HRVA, and atlantoaxial dislocation (AAD) were included. We designed a algorithm for alternative screw implantation into C2-3 fused vertebrae, including C2 pedicle screw with in-out-in (passing VA groove) technique (in-out-in screw), subfacetal screw, translaminar screw, lateral mass screw, C3 pedicle screw. VA diameter and position, C2 and C3 pedicles, superior facets, fused lamina, and fused lateral mass dimensions were evaluated for screw implantation indication. Implant failure, reduction loss, implant placement accuracy were investigated by computed tomography.
RESULTS: A total of 5 VAs were identified as distant VAs; a total of 2 VAs were categorized as occlusive VAs. Sufficient dimension of lateral mass and lamina provided the broadest indications for screw implantation, while the distant or occlusive VA provided the most limited indications for in-out-in screw. The indications of five alternative methods ranged from narrowest to widest as follows: in-out-in screw, C3 pedicle screw, subfacetal screw, translaminar screw, lateral mass screw. The translaminar screws and the lateral mass screws increased the probability of implant failure. All patients who received in-out-in screws, C3 pedicle screws, and subfacetal screws achieved fusion. The accuracy ranged from lowest to highest as follows: C3 pedicle screw, lateral mass screw, in-out-in screw, subfacetal screw, translaminar screw. No translaminar screws deviated.
CONCLUSIONS: The algorithm proved to be a valuable tool for screw selection in cases of C2-3 fused vertebrae with HRVAs. The subfacetal screw, boasting broad indications, a high fusion rate, and exceptional accuracy, stood as the primary preferred alternative.