Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.
Neurosurg Focus. 2010 Jun;28(6):E10. doi: 10.3171/2010.3.FOCUS1052.
Dynamic stabilization systems are used to stabilize degenerative lumbar spondylosis. Loosening of the pedicle screws in such nonfusion implants is predictable. This retrospective study evaluated the incidence of screw loosening and its effect on clinical outcomes.
Charts, radiographic films, and medical records of 71 consecutive patients who underwent decompression using Dynesys dynamic stabilization for 1- or 2-level lumbar spondylosis were reviewed. Radiographic films were evaluated and compared to detect screw loosening. A visual analog scale (VAS) for back pain and the Oswestry Disability Index (ODI) were used for measuring clinical outcome. Statistical analysis was conducted using the chi-square test and Student t-test.
The 71 patients in the study sample had a mean age of 59.2 +/- 11.65 years (range 23-80 years), with slight female predominance (39 women, 32 men). The mean follow-up duration was 16.6 months (range 8-29 months). There were loose screws in 14 of 71 patients (19.7%), for a rate of 4.6% per screw (17 of 368 screws). Most screw loosening occurred in patients >/= 55 years old (13 of 14 patients) although age and sex had no effect on screw loosening (p = 0.233 and 0.109, respectively). Both the loose screw and solid screw groups experienced significant improvement after the surgery in VAS and ODI scores. On the VAS, scores improved from 5.9 +/- 2.99 to 2.1 +/- 2.14 in the loose screw group (p = 0.003), and from 5.7 +/- 3.45 to 2.9 +/- 2.68 in the solid screw group (p < 0.001). For the ODI scale, scores improved from 43.5 +/- 16.78% to 28.0 +/- 18.18% (p = 0.006) in the loose screw group, and from 52.1 +/- 20.92% to 24.6 +/- 19.78% (p < 0.001) in the solid screw group. There were no significant differences between the 2 groups (p = 0.334 for VAS, p = 0.567 for ODI).
The preliminary study of this pedicle-based dynamic stabilization device for 1- and 2-level lumbar spondylosis shows radiographic evidence of screw loosening in 19.7% of patients and 4.6% of screws. Nonetheless, the loosening of screws has no adverse effect on clinical improvement.
动态稳定系统用于稳定退行性腰椎疾病。在这种非融合植入物中，椎弓根螺钉的松动是可以预测的。本回顾性研究评估了螺钉松动的发生率及其对临床结果的影响。
对 71 例因 1 或 2 节段腰椎病接受 Dynesys 动力稳定减压治疗的连续患者的图表、影像学资料和病历进行了回顾性分析。评估影像学资料并比较以发现螺钉松动。使用视觉模拟量表（VAS）评估腰痛，使用 Oswestry 残疾指数（ODI）评估临床结果。使用卡方检验和学生 t 检验进行统计分析。
71 例研究样本的患者平均年龄为 59.2 +/- 11.65 岁（范围 23-80 岁），女性略多（39 例女性，32 例男性）。平均随访时间为 16.6 个月（范围 8-29 个月）。71 例患者中有 14 例（19.7%）出现螺钉松动，螺钉松动率为 4.6%（368 颗螺钉中有 17 颗）。尽管年龄和性别对螺钉松动没有影响（p = 0.233 和 0.109），但大多数螺钉松动发生在年龄大于等于 55 岁的患者中（14 例患者中有 13 例）。在 VAS 和 ODI 评分方面，松动螺钉组和固定螺钉组术后均有显著改善。在 VAS 中，松动螺钉组的评分从 5.9 +/- 2.99 改善至 2.1 +/- 2.14（p = 0.003），固定螺钉组的评分从 5.7 +/- 3.45 改善至 2.9 +/- 2.68（p < 0.001）。在 ODI 量表中，松动螺钉组的评分从 43.5 +/- 16.78%改善至 28.0 +/- 18.18%（p = 0.006），固定螺钉组的评分从 52.1 +/- 20.92%改善至 24.6 +/- 19.78%（p < 0.001）。两组之间无显著差异（p = 0.334 用于 VAS，p = 0.567 用于 ODI）。
本研究初步探讨了基于椎弓根的 1 级和 2 级腰椎疾病动力稳定装置，发现 19.7%的患者和 4.6%的螺钉存在影像学证据的螺钉松动。尽管如此，螺钉松动对临床改善没有不良影响。
