1. Department of Neurosurgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China
2. Department of Neurosurgery, The Third People's Hospital of Heze City, Heze, Shandong 274031, P.R. China
3. Department of Neurosurgery, The First People's Hospital of Tai'an, Tai'an, Shandong 271000, P.R. China
4. Department of Obstetrics and Gynecology, Jinan Maternity and Child Care Hospital, Jinan, Shandong 250021, P.R. China
5. Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, P.R. China