1 Department of Surgery and Anatomy, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes, 3900, City of Ribeirão Preto, State of São Paulo, 14048-900, Brazil. rsparra@hcrp.usp.br.
2 Department of Surgery and Anatomy, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes, 3900, City of Ribeirão Preto, State of São Paulo, 14048-900, Brazil.