Teoh K H, von Ruhland C, Evans S L, James S H, Jones A, Howes J, Davies P R, Ahuja S
University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK.
Cardiff University, Heath Park, Cardiff, CF14 5DX, UK.
Bone Joint J. 2016 Dec;98-B(12):1662-1667. doi: 10.1302/0301-620X.98B12.38061.
We present a case series of five patients who had revision surgery following magnetic controlled growing rods (MGCR) for early onset scoliosis. Metallosis was found during revision in four out of five patients and we postulated a mechanism for rod failure based on retrieval analysis.
Retrieval analysis was performed on the seven explanted rods. The mean duration of MCGR from implantation to revision was 35 months (17 to 46). The mean age at revision was 12 years (7 to 15; four boys, one girl).
A total of six out of seven rods had tissue metallosis and pseudo-capsule surrounding the actuator. A total of four out of seven rods were pistoning. There were two rods which were broken. All rods had abrasive circumferential markings. A significant amount of metal debris was found when the actuators were carefully cut open. Analytical electron microscopy demonstrated metal fragments of predominantly titanium with a mean particle size of 3.36 microns (1.31 to 6.61).
This study highlights concerns with tissue metallosis in MCGR. We recommend careful follow-up of patients who have received this implant. Cite this article: Bone Joint J 2016;98-B:1662-7.
我们报告了一组5例接受磁控生长棒（MGCR）治疗早发性脊柱侧弯后进行翻修手术的病例。5例患者中有4例在翻修时发现金属沉着症，我们基于取出分析推测了棒体失效的机制。
对7根取出的棒体进行了取出分析。从植入到翻修，MGCR的平均使用时长为35个月（17至46个月）。翻修时的平均年龄为12岁（7至15岁；4名男孩，1名女孩）。
7根棒体中有6根出现组织金属沉着症以及围绕驱动器的假包膜。7根棒体中有4根出现活塞样运动。有2根棒体断裂。所有棒体均有磨损的圆周痕迹。小心切开驱动器时发现了大量金属碎屑。分析电子显微镜显示，金属碎片主要为钛，平均粒径为3.36微米（1.31至6.61微米）。
本研究强调了MGCR中组织金属沉着症的问题。我们建议对接受该植入物的患者进行密切随访。引用本文：《骨与关节杂志》2016年；98 - B：1662 - 1667。
