Guide tube for guiding endoscope or surgical tool in or into body cavity

A guide tube for guiding an endoscope or a surgical tool in or into a body cavity, comprising:

• an inner tube having open fore and rear ends and a longitudinal axis, along with flexibility in bending directions;
• an outer tube disposed to enshroud said inner tube and directly or indirectly connected to said fore and rear ends of said inner tube, said outer tube having flexibility in bending directions;
• at least one elongated muscle member located in a hermetically closed space defined between said inner and outer tubes in parallel relation with said longitudinal axis of said inner tube, and having an engaging surface on inner or outer side to be brought into pressed engagement with at least one of said inner and outer tubes, said muscle member being attached to an elongated strength retention member having no elasticity in a longitudinal direction but having flexibility in bending directions;
• a restraint member provided at least on one of said inner and outer tubes and adapted to restrain said muscle member of dislodgement in a circumferential direction about said longitudinal axis from a predetermined angular or radial position on said inner tube;
• and
• a fluid evacuation means connected to said guide tube for communication with said hermetically closed space between said inner and outer tubes, said evacuation means being switched on to evacuate a fluid from said closed space, bringing said engaging surface into pressed engagement with said inner or outer tube to transform said guide tube into a highly rigid structure, and switched off at the time of restoring flexibility of said guide tube by introduction of a fluid in said closed space.