An over-tube was developed for receiving and guiding endoscopic instruments into a patients anus, through the colon, and into the peritoneum. The over-tube has a flexible sheath adapted for insertion into the anus through the colon and out the peritoneum of a patient. A stiffened region is used to protect the colonic wall from injury during insertion of medical instruments through the patients lower gastrointestinal tract. The proximal end of the over-tube is surrounded by two narrow inflatable balloons on either side of the colotomy to keep the device in place with its lumen open into the peritoneum and further prevent leakage of insufflation. The device may comprise two channels, one for duel channel endoscopes and larger medical instruments or single lumen endoscopes, and an additional channel for surgical instruments. A distal valve prevents insufflation leakage, making the device especially useful in NOTES surgeries.
