1. Department of NeurosurgeryThe Second Affiliated Hospital of Xi'an Jiaotong University Xi'an Shaanxi 710004 P. R. China
2. Department of DermatologyAffiliated Hospital of Yan'an University Yan'an Shaanxi 716000 P. R. China
3. Department of DermatologyThe Second Affiliated Hospital of Xi'an Jiaotong University Xi'an Shaanxi 710004 P. R. China