Beastall James, Karadimas Efthimios, Siddiqui Manal, Nicol Malcolm, Hughes Justin, Smith Francis, Wardlaw Douglas
Woodend Hospital, Aberdeen, Scotland.
Spine (Phila Pa 1976). 2007 Mar 15;32(6):685-90. doi: 10.1097/01.brs.0000257578.44134.fb.
We present the positional magnetic resonance imaging findings of a prospective case series of patients undergoing surgery with the Dynesys spinal stabilization device (Zimmer, Inc., Warsaw, IN).
To explore the biomechanical impact of the Dynesys device in vivo.
Spinal fusion surgery is widely used for painful degenerative conditions of the lumbar spine that have not responded to conservative measures. It often produces good outcomes but can be associated with adjacent segment hypermobility that may lead to further degeneration and pain. Previous cadaveric biomechanical studies claim that the Dynesys Dynamic Spinal Stabilization System allows some lumbar movement, behaving similar to a normal spine in extension but similar to rigid fixation in flexion.
Twenty-four patients with dominant low back pain, with or without leg pain, were treated with the Dynesys. All patients underwent positional magnetic resonance imaging before surgery and 9 months after surgery. Measurements were made to assess the differences at the operated level, adjacent level, and whole lumbar spine.
There was a statistically significant reduction in flexion-extension range of movement of both the whole lumbar spine by 13.37 degrees (P = 0.002) and at the instrumented segments by 4.08 degrees (P < 0.001) following surgery. There was an insignificant reduction in range of movement at the level above instrumentation (P = 0.807). Mean anterior disc height at the instrumented level reduced by 0.7 mm following insertion of the Dynesys (P < 0.027). Mean posterior disc height reduced by 0.3 mm (P = 0.453). In a neutral posture, the Dynesys had no significant impact on lordosis or inclination of operated or adjacent levels. Contrary to cadaveric study findings, the Dynesys appears to restrict extension more than flexion with respect to a neutral posture.
In vivo, the Dynesys Stabilization System allows movement at the instrumented level, albeit reduced, with no significant increased mobility at the adjacent segments. There was reduction of the anterior disc height without a significant increase of the posterior disc height.
我们展示了一组使用Dynesys脊柱稳定装置（Zimmer公司，印第安纳州华沙）进行手术的前瞻性病例系列的位置磁共振成像结果。
探讨Dynesys装置在体内的生物力学影响。
脊柱融合手术广泛用于对保守治疗无反应的腰椎疼痛性退变疾病。它通常能产生良好的效果，但可能与相邻节段的活动过度相关，这可能导致进一步退变和疼痛。先前的尸体生物力学研究表明，Dynesys动态脊柱稳定系统允许一些腰椎运动，在伸展时表现类似于正常脊柱，而在屈曲时类似于刚性固定。
24例以腰痛为主、有或无腿痛的患者接受了Dynesys治疗。所有患者在手术前和手术后9个月均接受了位置磁共振成像检查。进行测量以评估手术节段、相邻节段和整个腰椎的差异。
手术后，整个腰椎的屈伸活动范围在统计学上显著减小了13.37度（P = 0.002），器械固定节段减小了4.08度（P < 0.001）。器械固定节段上方节段的活动范围减小不显著（P = 0.807）。植入Dynesys后，器械固定节段的平均椎间盘前缘高度降低了0.7毫米（P < 0.027）。平均椎间盘后缘高度降低了0.3毫米（P = 0.453）。在中立姿势下，Dynesys对手术节段或相邻节段的前凸或倾斜度没有显著影响。与尸体研究结果相反，相对于中立姿势，Dynesys似乎对伸展的限制比对屈曲的限制更大。
在体内，Dynesys稳定系统允许器械固定节段进行活动，尽管活动度减小，且相邻节段的活动度没有显著增加。椎间盘前缘高度降低，而后缘高度没有显著增加。
