1. Department of Neurosurgery Rui‐Jin Hospital Shanghai Jiao Tong University School of Medicine Shanghai 200025 P. R. China
2. Cixi Institute of Biomedical Engineering International Cooperation Base of Biomedical Materials Technology and Application Chinese Academy of Sciences Key Laboratory of Magnetic Materials and Devices Zhejiang Engineering Research Center for Biomedical Materials Ningbo Institute of Materials Technology and Engineering, CAS Ningbo 315201 P. R. China
3. Department of Neurosurgery The Second Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310009 P. R. China