Center for Spine and Spinal Cord Disorders, Southern Tohoku General Hospital, 1-2-5 Satonomori, Iwanuma, Miyagi 989-2483, Japan.
Eur Spine J. 2012 May;21(5):946-55. doi: 10.1007/s00586-011-2090-1. Epub 2011 Nov 29.
Development of adjacent segment degeneration following anterior cervical decompression and fusion (ACDF) is still controversial, as adjacent-level kinematics is poorly understood. This study reports preliminary data from a high-accuracy 3D analysis technique developed for in vivo cervical kinematics.
From nine cervical spondylosis patients, four underwent single-level ACDF, and five underwent two-level ACDF using cylindrical titanium cage implant(s). Pre- and post-surgical CT scans were taken in flexion, neutral and extended positions, allowing us to compute segmental ranges of motion for rotation and translation, and 3D disc-height distributions. Differences in segmental motions and disc-height between fused and adjacent levels were analyzed with a Wilcoxon signed-rank test. Results are presented as mean ± SEM.
The flexion/extension angular-ROM at the fusion level decreased after surgery (7.46 ± 1.17° vs. 3.14 ± 0.56°, p < 0.003). The flexion/extension angular-ROM at one caudal adjacent level to the fusion level (3.97 ± 1.29°) tended to be greater post-operatively (6.11 ± 1.44°, p = 0.074). Translation in the anterior-posterior direction during flexion/extension at the fusion level decreased after surgery (1.22 ± 0.20 mm vs. 0.32 ± 0.11 mm, p < 0.01). No differences were found in adjacent-level disc heights between both study time-points.
This study showed increased segmental motion in flexion/extension angular-ROM at one level adjacent to ACDF. However, increases in the rotational angular-ROM were not statistically significant when cranial/caudal adjacent levels were analyzed separately. This preliminary study highlighted the capabilities of a 3D-kinematic analysis method to detect subtle changes in kinematics and disc height at the adjacent levels to ACDF. Thus, reliable evidence related to ACDF's influence on adjacent-level cervical kinematics can be collected.
颈椎前路减压融合术（ACDF）后相邻节段退变的发展仍存在争议，因为对相邻节段的运动学知之甚少。本研究报告了一种用于颈椎运动学体内分析的高精度 3D 分析技术的初步数据。
从 9 名颈椎病患者中，4 名患者接受了单节段 ACDF 手术，5 名患者接受了两节段 ACDF 手术，使用圆柱形钛笼植入物。在屈曲、中立和伸展位置拍摄术前和术后 CT 扫描，使我们能够计算旋转和平移的节段运动范围，以及 3D 椎间盘高度分布。采用 Wilcoxon 符号秩检验分析融合和相邻节段的节段运动和椎间盘高度差异。结果以平均值±SEM 表示。
融合水平的屈伸角运动范围（ROM）术后减小（7.46 ± 1.17°对 3.14 ± 0.56°，p < 0.003）。融合水平下一个尾侧相邻节段的屈伸角 ROM（3.97 ± 1.29°）术后趋于更大（6.11 ± 1.44°，p = 0.074）。融合水平在屈伸过程中前后方向的平移术后减小（1.22 ± 0.20 mm 对 0.32 ± 0.11 mm，p < 0.01）。在两个研究时间点之间，相邻节段的椎间盘高度没有差异。
本研究显示，ACDF 相邻节段屈伸角 ROM 增加。然而，当单独分析颅侧/尾侧相邻节段时，旋转角 ROM 的增加没有统计学意义。这项初步研究强调了 3D 运动学分析方法检测 ACDF 后相邻节段运动学和椎间盘高度细微变化的能力。因此，可以收集到与 ACDF 对相邻颈椎运动学影响相关的可靠证据。
