Fayyazi Amir H, Ordway Nathaniel R, Park Soo-An, Fredrickson Bruce E, Yonemura Kenneth, Yuan Hansen A
Penn State College of Medicine, Center for Advanced Healthcare, PA, USA.
J Spinal Disord Tech. 2010 Jun;23(4):236-41. doi: 10.1097/BSD.0b013e3181a4bb0b.
Prospective case series
This was designed to precisely measure motion after posterior dynamic stabilization using Dynesys instrumentation.
The Dynesys posterior dynamic stabilization system, which stabilizes the spinal segment while potentially decreasing the risk of adjacent segment disease, is undergoing evaluation by the US Food and Drug Administration for treatment of degenerative spondylolisthesis without fusion. Evaluation of adjacent segment disease requires precise characterization of motion on the surgical level. Unfortunately, routine clinical radiographic techniques are imprecise and unreliable for full characterization of spinal segment motion. Radiostereometric analysis, which is very precise and reliable for in vivo measurement of motion, was used to examine spinal segment motion after dynamic stabilization with Dynesys.
Six patients (age 59+/-7 y) underwent posterior decompression followed by posterior stabilization using Dynesys instrumentation (4 one-level, 2 two-levels). Three to 5 tantalum beads were placed in each vertebral body. Postoperative biplanar radiographs were obtained in flexion, extension, right, and left lateral bending, and 3-dimensional reconstruction was performed using radiostereometric analysis at 3, 6, 12, and 24 months postoperatively. The translations and rotations of the superior vertebral body were measured relative to the inferior vertebral body.
Over the 24-month follow-up period, mean flexion, extension, left, and right lateral bending of the motion segments were noted to be 1.0 degrees, 2.4 degrees, 0.6 degrees, and 0.6 degrees or less, respectively. There were no statistically significant changes in the degree of motion. During follow-up, no significant changes in neutral position of the device were noted in any of the 3 planes, and minimal translation was noted in the postoperative period.
The Dynesys dynamic instrumentation system seems to stabilize degenerative spondylolisthesis. As expected in the degenerative lumbar spine, the segmental motion of the implanted level in this study was limited and considerably less than normal spinal motion.
前瞻性病例系列
本研究旨在精确测量使用Dynesys器械进行后路动态稳定术后的运动情况。
Dynesys后路动态稳定系统在稳定脊柱节段的同时，可能降低相邻节段疾病的风险，美国食品药品监督管理局正在对其用于治疗退变性腰椎滑脱症且无需融合的情况进行评估。对相邻节段疾病的评估需要在手术层面精确描述运动情况。不幸的是，常规临床放射学技术在全面描述脊柱节段运动方面不够精确且不可靠。放射立体测量分析对于体内运动测量非常精确且可靠，被用于检查使用Dynesys进行动态稳定术后的脊柱节段运动。
6例患者（年龄59±7岁）接受了后路减压，随后使用Dynesys器械进行后路稳定术（4例单节段，2例双节段）。每个椎体放置3至5颗钽珠。术后在屈曲、伸展、右侧和左侧侧弯位获取双平面X线片，并在术后3、6、12和24个月使用放射立体测量分析进行三维重建。测量上位椎体相对于下位椎体的平移和旋转。
在24个月的随访期内，运动节段的平均屈曲、伸展、左侧和右侧侧弯分别为1.0度、2.4度、0.6度和0.6度或更小。运动程度无统计学显著变化。随访期间，在任何一个平面中均未发现器械中立位有显著变化，术后平移极小。
Dynesys动态器械系统似乎能稳定退变性腰椎滑脱症。正如退变性腰椎所预期的那样，本研究中植入节段的节段性运动受限，且远低于正常脊柱运动。
