A colonic overtube 1 for maintaining a sigmoid colon in a straightened configuration has a proximal end 2 for location externally of a colon, and a distal end 3 for insertion into a colon. A colonoscope lumen 4 extends through the overtube 1 to facilitate passing the overtube 1 over a colonoscope. The...http://www.google.com/patents/US6793621?utm_source=gb-gplus-sharePatent US6793621 - Colonic overtube
