A novel biodegradable frontal sinus stent (MgNd2): a long-term animal study

The frontal sinus recess consists of anatomically narrow passages that are prone to stenosis in endonasal frontal sinus surgery for chronic sinus disease. Over the past 100 years, diverse frontal sinus stents have been developed and evaluated in clinical and animal studies. However, superinfection, formation of granulations tissue, stent dislocation and late stenosis of the duct have remained challenges and subject of debate in the literature. Currently developed biodegradable materials, including rare earth-containing magnesium alloys are promising candidates for application as temporary implant materials. The Mg 2 % wt Nd alloy (MgNd2) was used to design a nasal stent that fit the porcine anatomy. In the current study, we evaluate biocompatibility, biodegradation and functionality of a frontal sinus stent in 16 minipigs over 6 months. Intraoperative endoscopy revealed free stent lumen in all cases. Blood examination and clinical examinations indicated no systematic or local inflammation signs. The histopathology and elements analysis showed a very good biocompatibility. The μ-computed tomography-based volumetric analysis showed substantial stent degradation within 6 months. Our MgNd2 based stent appears to be a promising, solid basis for the development of a frontal sinus stent for clinical use.