[1] Univ Virginia Hlth Syst, Dept Surg, POB 800709, Charlottesville, VA 22901 USA
[2] Univ Virginia Hlth Syst, Dept Anesthesia, Charlottesville, VA USA
[3] Inova Fairfax Hosp, Dept Surg, Annandale, VA USA
[4] Winchester Med Ctr, Winchester, VA USA
[5] Virginia Tech, Caril Sch Med, Dept Surg, Roanoke, VA USA
[6] Caril Clin, Roanoke, VA USA