Panagiotopoulou Vasiliki C, Tucker Stewart K, Whittaker Robert K, Hothi Harry S, Henckel Johann, Leong Julian J H, Ember Thomas, Skinner John A, Hart Alister J
Institute of Orthopaedics and Musculoskeletal Science, Royal National Orthopaedic Hospital, University College London, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK.
The Royal National Orthopaedic Hospital, Stanmore, UK.
Eur Spine J. 2017 Jun;26(6):1699-1710. doi: 10.1007/s00586-016-4936-z. Epub 2017 Jan 19.
We aim to describe a mechanism of failure in magnetically controlled growth rods which are used for the correction of the early onset scoliosis.
This retrieval study involved nine magnetically controlled growth rods, of a single design, revised from five patients for metal staining, progression of scoliosis, swelling, fractured actuator pin, and final fusion. All the retrieved rods were radiographed and assessed macroscopically and microscopically for material loss. Two implants were further analysed using micro-CT scanning and then sectioned to allow examination of the internal mechanism. No funding was obtained to analyse these implants. There were no potential conflicts interests.
Plain radiographs revealed that three out of nine retrieved rods had a fractured pin. All had evidence of surface degradation on the extendable telescopic rod. There was considerable corrosion along the internal mechanism.
We found that a third of the retrieved magnetically controlled growth rods had failed due to pin fracture secondary to corrosion of the internal mechanism. We recommend that surgeons consider that any inability of magnetically controlled growth rods to distract may be due to corrosive debris building up inside the mechanism, thereby preventing normal function.
我们旨在描述用于矫正早发性脊柱侧弯的磁控生长棒的一种失效机制。
这项回顾性研究涉及9根单一设计的磁控生长棒，这些生长棒取自5例患者，用于评估金属染色、脊柱侧弯进展、肿胀、致动器销断裂及最终融合情况。对所有取出的生长棒进行X线摄影，并进行宏观和微观评估以确定材料损失情况。另外对两根植入物进行了显微CT扫描分析，然后进行切片以检查内部机制。未获得分析这些植入物的资金。不存在潜在利益冲突。
X线平片显示，9根取出的生长棒中有3根销钉断裂。所有生长棒的可伸缩杆表面均有降解迹象。内部机制存在大量腐蚀。
我们发现，三分之一的取出磁控生长棒失效是由于内部机制腐蚀继发销钉断裂。我们建议外科医生应考虑到磁控生长棒无法撑开可能是由于机制内部积聚了腐蚀性碎片，从而妨碍了正常功能。
