1 Section of Minimally Invasive Surgery, General Surgery, Washington University in St. Louis School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO, 63110, USA. wtan@wustl.edu.
2 Section of Minimally Invasive Surgery, General Surgery, Washington University in St. Louis School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO, 63110, USA.