US Patent 7837615 Shape lockable apparatus and method for advancing an instrument through unsupported anatomy

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 or liner, and a distal region having an atraumatic tip. The sheath/liner may be disposable to permit reuse of the overtube. Loading devices may be provided for disposing the sheath/liner about the overtube. Tensioning mechanisms may be provided to selectively stiffen the overtube to reduce distension of the organ caused by advancement of the diagnostic or therapeutic instrument. The distal region permits passive steering of the overtube caused by deflection of the diagnostic or therapeutic instrument, while the atraumatic tip prevents the wall of the organ from becoming caught or pinched during manipulation of the diagnostic or therapeutic instrument.