AUTHOR=Jiang Guozheng , Wang Shuyang , Xu Luchun , Li Zeyu , Feng Ningning , Qiu Ziye , Yang Yongdong , Yu Xing TITLE=Biomechanical effects of screw loosening after lumbar PEEK rod and titanium rod fixation: a finite element analysis JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=Volume 13 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2025.1533088 DOI=10.3389/fbioe.2025.1533088 ISSN=2296-4185