An alternative approach for blocking the superior trunk of the brachial plexus evaluated by a single arm clinical trial oleh Thiago Nouer Frederico, Rioko Kimiko Sakata, Luiz Fernando dos Reis Falc.·o, Paulo Ces..r Castello Branco de Sousa, Fernanda Melhmann, Cesar Augusto Sim..es, Leonardo Henrique Cunha Ferraro