1 Department of General, Visceral, and Transplant Surgery, Medical Center University Duisburg-Essen, Essen, Germany.
2 Department of Anesthesiology and Perioperative Medicine, Penn State Hershey Medical Center, Penn State College of Medicine, Hershey, PA.
3 Department of General, Visceral, and Transplant Surgery, Medical Center University Duisburg-Essen, Essen, Germany. Electronic address: fuat.saner@uni-due.de.