1. Department of Surgery, University of California, Irvine (UCI), Orange, CA, USA
2. Department of Surgery, Los Angeles County/University of Southern California Medical Center, Los Angeles, CA, USA
3. Department of Surgery, Ventura County Medical Center, Ventura, CA, USA
4. Comparative Effectiveness and Clinical Outcomes Research Center – CECORC, Riverside University Health System Medical Center, Moreno Valley, CA, USA
5. Department of Surgery, Santa Barbara Cottage Hospital, Santa Barbara, CA, USA
6. Department of Surgery, Huntington Hospital, Pasadena, CA, USA
7. Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
8. Department of Surgery, Scripps Memorial Hospital, San Diego, CA, USA
9. Department of Surgery, University of California, Los Angeles (UCLA), Los Angeles, CA, USA