Guo Xiang, Ni Bin, Zhao Weidong, Wang Mingfei, Zhou Fengjin, Li Songkai, Ren Zhongwu
Department of Orthopedics, The Second Affiliated Hospital, The Second Military Medical University, Shanghai, People's Republic of China.
J Spinal Disord Tech. 2009 Dec;22(8):578-85. doi: 10.1097/BSD.0b013e31818da3fe.
STUDYDESIGN: In vitro biomechanical test was conducted to compare the stability of 5 different atlantoaxial posterior fusion techniques.
To evaluate the biomechanical stability of an atlas laminar hook combined with transarticular (TA) screws relative to 4 different conventional fusion techniques.
The atlantoaxial instability caused by fractures, rheumatoid arthritis, congenital deformity, or traumatic lesions of the transverse ligament often result in acute or chronic spinal cord compression, a possible threat to a patient's life. Posterior atlantoaxial fixations are used to reconstruct the stability of atlantoaxial articulation. Conventional posterior atlantoaxial fixations are associated with high rates of pseudoarthrosis and carry the potential risk of neurologic complication. TA screw fixation can provide an excellent biomechanical stability. As a modified 3-point fixation technique, the bilateral C1-2 TA screws have been combined with C1 laminar hook and bone grafts. This modified technique had carried good clinical outcomes.
Eight human specimens (C0-C4) were loaded nondestructively with pure moments and the range of motion at the level of C1-C2 was measured. Eight specimens were implanted with each of the following techniques, respectively: Gallie fixation, C1-2 TA screw fixation combined with Gallie fixation, C1-2 TA screw fixation, C1 laminar hook combined with C1-2 TA screw fixation plus bone grafts, and the C1 lateral mass screws in the atlas combined with C2 isthmic screws in axis.
Although the C1-2 TA screws best restricted lateral bending and axial rotation, the modified 3-point fixation technique additionally restricted flexion-extension and provided the excellent stability. Differences in axial rotation and lateral bending (with + or - 1.5 Nm load) were observed when the 3-point fixation techniques (TA + Gallie and TA + hook) were compared with atlas lateral mass screws in the atlas combined with isthmic screws in axis.
The modified C1 laminar hook combined with C1-2 TA screws and bone graft fixation provided the best biomechanical stability. The C1 lateral mass screws in the atlas combined with isthmic screws in axis fixation is a sound alternative when the C1-2 TA screw fixation is not feasible.
进行体外生物力学测试以比较5种不同寰枢椎后路融合技术的稳定性。
评估寰椎椎板钩联合经关节（TA）螺钉相对于4种不同传统融合技术的生物力学稳定性。
由骨折、类风湿性关节炎、先天性畸形或横韧带创伤性损伤引起的寰枢椎不稳常导致急性或慢性脊髓压迫，对患者生命构成潜在威胁。寰枢椎后路固定用于重建寰枢关节的稳定性。传统的寰枢椎后路固定假关节形成率高，且有神经并发症的潜在风险。TA螺钉固定可提供出色的生物力学稳定性。作为一种改良的三点固定技术，双侧C1-2 TA螺钉已与C1椎板钩和植骨联合使用。这种改良技术取得了良好的临床效果。
对8个尸体标本（C0-C4）施加无损纯力矩，并测量C1-C2水平的活动范围。分别用以下每种技术植入8个标本：加利固定法、C1-2 TA螺钉固定联合加利固定法、C1-2 TA螺钉固定、C1椎板钩联合C1-2 TA螺钉固定加植骨，以及寰椎的C1侧块螺钉联合枢椎的C2峡部螺钉。
虽然C1-2 TA螺钉对侧方弯曲和轴向旋转的限制最佳，但改良的三点固定技术还额外限制了屈伸，并提供了出色的稳定性。当将三点固定技术（TA+加利和TA+钩）与寰椎的侧块螺钉联合枢椎的峡部螺钉进行比较时，观察到轴向旋转和侧方弯曲（在±1.5 Nm负荷下）存在差异。
改良的C1椎板钩联合C1-2 TA螺钉及植骨固定提供了最佳的生物力学稳定性。当C1-2 TA螺钉固定不可行时，寰椎的C1侧块螺钉联合枢椎的峡部螺钉固定是一种合理的替代方法。
