Overtube for endoscope

An overtube for an endoscope, comprising:

• a multi-lumen tube body having a main lumen through which the endoscope is inserted and an air-supply lumen through which gas flows, each of the main lumen and the air-supply lumen extend parallel to each other and to a longitudinal axis of the multi-lumen tube body;
• a fixing balloon provided on an outer peripheral surface of a distal end of the tube body, expandable outward from the outer peripheral surface and contractible toward the outer peripheral surface;
• an air supply device configured to send the gas to the air-supply lumen;
• and
• an airtight valve unit having a tubular portion communicating with the main lumen at a rear end of the tube body, the airtight valve unit closing a gap between the endoscope inserted through the tubular portion into the main lumen and an inner peripheral surface of the tubular portion;
• wherein the tube body comprises:
• a first region including the air-supply lumen, and formed in a thick portion where a thickness defined by a distance between the outer peripheral surface and the inner peripheral surface in the radial direction is greater than a thickness of a constant thickness portion that is constant in a circumferential direction;
• and
• a second region adjacent to the first region in the circumferential direction and having lower rigidity than either the constant-thickness portion or the first region.

An overtube for an endoscope, comprising:

• a tube body having a main lumen through which the endoscope is inserted and an air-supply lumen through which gas flows;
• a fixing balloon provided on an outer peripheral surface of a distal end of the tube body, expandable outward from the outer peripheral surface and contractible toward the outer peripheral surface;
• an air supply device configured to send the gas to the air-supply lumen;
• and
• an airtight valve unit having a tubular portion communicating with the main lumen at a rear end of the tube body, the airtight valve unit closing the gap between the endoscope inserted through the tubular portion into the main lumen and an inner peripheral surface of the tubular portion;
• wherein the tube body comprises:
• a first region including the air-supply lumen, and formed in a thick portion where a thickness defined by a distance between the outer peripheral surface and the inner peripheral surface in the radial direction is greater than a thickness of a constant thickness portion that is constant in a circumferential direction;
• and
• a second region adjacent to the first region in the circumferential direction and having lower rigidity than either the constant-thickness portion or the first region.