An overtube for use with an endoscopic surgical instrument. In various embodiments, the overtube may comprise a hollow tubular member that has an implantable tip detachably affixed to a distal end thereof. The implantable tip may have at least one retention member formed thereon to retain the tip within an organ wall. The implantable tip may further have a lumen extending therethrough to form a passageway through the organ wall. A plug member may be provided to selectively seal off the lumen within the implantable tip.
