颈椎前、后路手术的运动学变化

Biomechanics of Anterior and Posterior Operations in Cervical Spine

目的：为评价几种颈椎前、后路手术对颈椎稳定性的影响。方法：取四具意外伤亡的新鲜尸体Ｃ２～Ｔ１标本，保留所有韧带和椎间连接，行如下手术：１．Ｃ５，６椎间盘切除；２．椎间植骨；３．前方椎体钢板螺钉内固定；４．Ｃ５全椎板减压；５．Ｃ５，６椎弓根钢板螺钉内固定（去除该部椎体钢板）；６．去除椎弓根钢板和植骨块。测量上述诸术Ｃ２～Ｔ１各节段间的前屈、后伸、左右侧弯，左右旋转运动变化，以完整标本作对照。结果：Ｃ５，６椎间盘切除后的前屈运动增加６７．８％（Ｐ＜０．０１），后伸运动增加５９％（Ｐ＜０．０１），侧弯和旋转运动增加１０％（Ｐ＞０．０５）。植骨后运动变化不明显（Ｐ＞０．０５）。椎体钢板和椎弓根内固定后各向运动均明显减少（Ｐ＜０．０１），以侧弯和旋转尤为明显，椎弓根固定后明显增强三维稳定性。而椎体钢板固定的旋转稳定性最佳。然椎间盘和椎板同时切除引起三维运动明显不稳。损伤和固定节段的运动增大和减小，伴随其相邻上或下节段运动的代偿性减小和增大，但无显著性。结论：以上结果为临床开展颈椎前。

To evaluate the influence to the stability of motion segments in cervical spine caused by some kinds of anterior and posterior operations, four fresh spinal specimens from C2～ T1 retaining intervertebral conjunctions and ligaments were used for the experimental study.The operations included: C5, 6 anterior discectomy; intervertebral bone graft;C5, 6 anterior plate fixation; total laminectomy at C5; removal of anterior plate then posterior pedicle screw plate fixation; removal of pedicle plate. The flexion, extension, left - right lateral bending and axial rotation were measured in intact state and following various operations above. The intact motion was as the control. The results showed that following C5, 6 discectomy the flexion motion was increased by 67.8% (P< 0.01), The extention motion was increased by 59% (P< 0.01). While lateral bending and rotation was increased slightly (10% , P >0.05). The smaller motion change was seen after bone graft(P >0.05). The three dimension movement was decreassed obviously following anterior plate or pedicle plate fixation in which lateral bending and rotation were more significant(P< 0. 01) .The stability of pedicle screw in flexion、 extension、 lateral bending and ratation was strong. The rotation stability after anterior plate was the strongest of all. The C5、 6 discetomy as well as total laminectomy caused hightly unstable in various directions of motion. The increasing motion at injured space was accampanied by decreasing motion at adjacent superior or inferior space. The decreasing motion at fixed level was accompanied by increasing motion at adjcent superior or inferior level. But not significant. The results provide the kinematics theory for clinical anterior and posterior operations in cervical spine as well as provide the biomechanical base for choosing the internal or extermal fixation .