表面改性技术降低生长棒临床并发症发生率研究进展

生长棒是应用于早发性脊柱侧凸患者矫正治疗的医疗器械.首先介绍了由钛合金或钴铬合金材料制造的单生长棒、双生长棒、Shilla生长棒等在早发性脊柱侧凸矫正领域的临床应用现状;同时总结了生长棒在体内服役时,由于金属疲劳、固定螺钉松动、植入物的磨损和腐蚀等原因导致的金属棒断裂、固定螺钉拔出、金属离子富集等问题,以及由此引起的过敏反应、炎症反应、骨溶解等相关并发症.为降低生长棒临床应用并发症发生率,国内外研究人员采用喷丸、微弧氧化、等离子喷涂、物理气相沉积等表面改性手段,对生长棒进行表面改性.国内外研究表明,采用激光冲击强化、喷丸等可以提高生长棒系统中金属棒的表面硬度及应力,提高金属棒的微动疲劳特性,避免金属棒断裂;采用喷丸、微弧氧化处理和等离子喷涂处理等方法,可以促进生长棒系统中椎弓根螺钉和天然骨界面长合,增强椎弓根螺钉-骨组织的结合强度;采用物理气相沉积可以提高生长棒系统的耐磨性、耐蚀性,进而降低其离子释放量.经过表面改性后的生长棒系统,生物相容性提高,过敏反应、炎症反应、骨溶解等相关并发症的发生率降低.

Advances in Research on Surface Modification to Reduce the Incidence of Clinical Complications of Growing Rods

The growing rod is a kind of medical device widely used in the corrective therapy of patients with early-onset scoliosis (EOS). In this paper, the clinical applications of growing rods, such as single growing rod, dual growing rod and Shilla growing rod, made of titanium alloy or cobalt chromium alloy, in the EOS treatment were introduced firstly. In addition, the problems such as rods breakage, pedicle screw extraction, and metal ion enrichment, which were caused by metal fatigue, screw loosening, wear, and corrosion during growing rods applied in vivo, were summarized. The related complications including allergic reaction, inflammatory response and osteolysis caused by such problems were also clarified. In order to reduce the incidence of clinical complications, researchers at home and abroad have improved the metal rod of growing rod system by surface modification, such as peening, micro arc oxidation, plasma spray and physical vapor deposition. These researches show as follows:The surface hardness and stress of metal rods of growing rod system can be improved by laser shock peening and cavitation peening, thus the fretting fatigue property can be improved to avoid metal rod fracture. Peening, micro arc oxidation, and plasma spray can promote the osseointegration of pedicle screw of growing rod system and bone interface, and enhance the pedicle screw-bone strength. The wear resistance and corrosion resistance of the growing rods can be enhanced by physical vapor deposition, which inhibits the metal ion release. After surface modification, the biocompatibility of the growing rods was improved, and the incidence of related complications such as allergic reaction, inflammatory response and osteolysis was reduced.