Apparatus and methods are provided for placing and advancing a diagnostic or therapeutic instrument in a hollow body organ of a tortuous or unsupported anatomy, comprising a handle, an overtube disposed within a hydrophilic sheath, and a distal region having an atraumatic tip. The overtube may be removable...http://www.google.de/patents/US20060111614?utm_source=gb-gplus-sharePatent US20060111614 - Shape lockable apparatus and method for advancing an instrument through unsupported anatomy
