Department of Ontological Surgery;
the Second AffiliatextHospital;
Medical College of Xi'an Jiaotong University;
Xi'an 710004;
Medical Research Center;
Affiliated Stomatological l-Iospital;
Medical College of Xi'an Jiaotong University;
Xi'an 710004;
Department of General Surgery;
the Second Affiliat~iHospital;
Medical College of Xi'an Jiaotong University;
Xi'an 710004;