脊柱胸腰段骨折术后椎弓根螺钉断裂及弯曲松动的原因分析

The analysis of postoperative breakage,bending and loosening of pedicle screws in the treatment of spinal fractures of the thoracolumbar segments

目的 探讨脊柱胸腰段骨折椎弓根螺钉系统内固定后，椎弓根螺钉断裂及弯曲松动的原因。方法 109例脊柱胸腰段骨折患者中有 23例 (24个椎体 )发生椎弓根螺钉断裂及弯曲松动。其中 14例螺钉断裂 (20枚螺钉 )， 2例螺母脱出、钉杆分离， 4例螺钉弯曲或松动， 3例连接杆断裂， 1例螺钉从上终板穿出。结果 椎弓根螺钉内固定系统发生问题的原因有 :（ 1）骨折节段未做植骨融合或用于横突间融合的骨床质量较差以致融合不牢。（ 2）椎弓根螺钉本身的设计缺陷。（ 3）起撑开复位作用的椎弓根螺钉系统负荷过大。（ 4）椎间盘退变造成椎间盘高度的丢失。（ 5）内置物取出过迟。（ 6）术后未佩戴支具或佩戴支具时间过短。结论 术中有效地植骨融合，选择设计合理的椎弓根螺钉，对合并有椎间盘损伤的患者合理选择手术适应证，尽早取出内置物以及术后常规佩戴支具能有效地防止椎弓根螺钉断裂及弯曲松动等问题的发生。

Objective To investigate the causes of breakage, bending and loosening of pedicle screw systems in fixation of spinal fractures of the thoracolumbar segments. Methods Pedicle screw breakage, bending and loosening found in 23 out of 109 cases of fractures of the thoracolumbar segments were studied. The failures included screw breakage in 14（ 20 screws） , dissociation of the rod in 2, breakage of the conjunction rod in 3, loosening and curving in 4 and penetrating the upper end plate in 1. Results The implants failure were resulted from: 1) bone graft was not used and the fusion was incomplete,2) deficiency of the pedicle screw design, 3)overloading of the pedicle screw,4)the degeneration of the intra vertebral disc leads to the loss of the vertebral body heights, 5) delayed implant removal, 6) no thoracolumbar protective brace had been adopted postoperatively. Conclusion Sound fusion by sucessful bone graft, use of rationally designed pedicle screws, correct indication selection,protective brace for postoperative rehabilitation and timely removal of the implant are valuable procedures for prevention of the implant failure.