Preliminary pneumoperitoneum facilitates transgastric access into the peritoneal cavity for natural orifice transluminal endoscopic surgery: A pilot study in a live porcine model - Ko, C -W; Shin, E J; Buscaglia, J M; Clarke, J O; Magno, P; Giday, S A; Chung, S S C; Cotton, P B; Gostout, C J; Hawes, R H; Pasricha, P J; Kalloo, A N; Kantsevoy, S V (Endoscopy, 2007)