1. Department of Neurosurgery, Binzhou Medical University Hospital , Binzhou , 256603 , China
2. Department of Gastroenterology, Binzhou Medical University Hospital , Binzhou , 256603 , China
3. Department of Neurosurgery, Shandong Provincial Hospital, Shandong University , No. 324, Jingwuweiqi Road , Jinan , 250021 , China