1 Department of Surgery, University of North Carolina School of Medicine, Chapel Hill, NC 7728, USA.
2 Department of Surgery, Kamuzu Central Hospital, Lilongwe, Malawi.
3 Department of Obstetrics and Gynecology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
4 Department of Surgery, University of North Carolina School of Medicine, Chapel Hill, NC 7728, USA; Department of Obstetrics and Gynecology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
5 Department of Surgery, University of North Carolina School of Medicine, Chapel Hill, NC 7728, USA; Department of Obstetrics and Gynecology, University of North Carolina School of Medicine, Chapel Hill, NC, USA. Electronic address: anthchar@med.unc.edu.