overtube

An overtube is a long, lubricated tube designed to be advanced over a flexible endoscope or other guide during endoscopic procedures. By providing a protected conduit through a natural lumen, an overtube helps prevent repeated mucosal trauma, allows smoother re-advancement of the scope, and can reduce the risk of aspiration in transoral procedures. Some overtubes are equipped with a distal balloon (balloon overtubes) to anchor the device or to straighten a tortuous GI tract, which can facilitate deep insertion, retrieval of foreign bodies, or staged instrument passage.

Overtubes are widely used in gastrointestinal endoscopy. In colonoscopy, they help minimize looping and improve stability during difficult insertions; in upper GI endoscopy, they support procedures such as ERCP or endoscopic ultrasound and can enable repeated scope exchanges without removing the overtube. Overtubes can also be employed to retrieve inaccessible polyps or foreign bodies or to guide stents into position.

Complications are uncommon but can include mucosal injury, perforation, bleeding, or airway complications in transoral use. Proper technique, lubrication, and patient selection are important; overtubes should be used by trained endoscopists in appropriate clinical settings.

History: The overtube was developed as endoscopy expanded, with balloon-assisted designs introducing additional control during challenging procedures.

See also: Endoscopy, Colonoscopy, ERCP, Balloon overtube.