1. Department of Surgery, Nikan Hospital, Tehran, Iran
2. Student Research Committee, Faculty of Medicine, Alborz University of Medical Sciences, Karaj, Iran
3. Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
4. Department of General Surgery, Ayatollah Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran