滑动环式椎弓根螺钉脊柱侧凸矫形系统的研制及动物实验研究

目的 通过生长期大型动物实验,考察滑动环式椎弓根钉脊柱侧凸矫形系统随脊柱生长的自动滑动性能及其对脊柱生长的影响.方法 将12只3个月龄幼山羊随机分为少锚定点组、多锚定点组及空白对照组.术前及术后1个月、3个月采用X线片、三维CT重建测量各组脊柱生长和环式椎弓根钉棒系统的滑动情况.实验结束后取手术节段脊柱进行大体标本观察.结果 各实验组三维CT重建及大体标本观察见椎体结构良好,发育正常;少锚定点组L5～T10脊柱生长长度为平均43.0 mm,钉棒滑动41.2 mm;多锚定点组L5～T10脊柱生长长度为平均43.5 mm,钉棒滑动39.4 mm;空白对照组L5～T10脊柱生长长度为平均40.9 mm.结论 滑动环式椎弓根钉脊柱侧凸矫形系统能够随脊柱生长而实现钉棒间的滑动.

Design and animal study of a posterior instrumentation system with sliding ring pedicle screws without arthrodesis in the immature spine

OBJECTIVE: To evaluate a sliding ring pedicle screw system without arthrodesis for the treatment of scoliosis in the immature spine. METHODS: Twelve goats of 3 months old were randomized into three groups: limited anchoring group, multi anchoring group, and blank contrast group. Growth of the spine and sliding of the instruments were assessed through conventional radiography and three dimentional CT reconstruction scan. Vertebral columns were resected 3 months after operation and pathological sections were observed. RESULTS: Three-dimensional CT scan and pathological analysis indicated no difference in structural development of the instrumented segments of the spine in the two operated groups as compared with the same segments of the spine in the control group. According to gross anatomic evaluation and radiographic measurement, the inrease in height from L5 to T10 averaged 43.0 mm in limited anchoring group, 43.5 mm in multi anchoring group and 40.9 mm in blank constrast group. Total sliding in the instrumentation system was 41.2 mm in limited anchoring group and 39.4 mm in multi anchoring group, respectively. There were no statistically significant difference in the longitudinal growth of the spine among the three groups. CONCLUSIONS: The sliding ring pedicle screw system can glide smoothly to accommodate the growth of the immature spine in an in vivo animal model.