1. From the Department of Surgery, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
2. Correspondence: Saud Al Shanafey, MD · Department of Surgery, King Faisal Specialist Hospital and Research Centre, MBC 40, PO Box 3354, Riyadh 11211, Saudi Arabia · T: +966-1-442-7754 F: +966-1-442-7772 · sashanafey@kfshrc.edu.sa · Accepted for publication June 2009
3. From the Department of Biostatistics, Epidemiology and Scientific Computing, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
4. From the Department of Surgery, King Abdulaziz Medical City, Riyadh, Saudi Arabia
5. From the Department of Surgery, King Khalid Hospital, Riyadh, Saudi Arabia