Method for transmitting torque and variably flexing a corrugated insertion device

1. A method for transmitting torque and variably flexing an insertion device for receiving an instrument, the method comprising the following steps:

providing a hollow body;

transmitting torque along the hollow body with a corrugated tube;

applying suction to create a vacuum in the hollow body for placing the hollow body in a relatively stiff condition;

relieving the vacuum for placing the hollow body in a relatively flexible condition;

maintaining the hollow body in the relatively flexible and relatively stiff conditions with tendons disposed within the hollow body, the vacuum created by the applied suction frictionally locking the tendons and the corrugated tube in place in the relatively stiff condition; and

individually adjusting at least some of the tendons in length for steering a distal end of the hollow body.

2. The method according to claim 1 , which further comprises preventing vacuum leakage and aiding in insertion of the instrument with a liner disposed within the corrugated tube.

3. The method according to claim 2 , which further comprises adhesively connecting the liner to the corrugated tube.

4. The method according to claim 1 , which further comprises carrying out the step of individually adjusting at least some of the tendons as steering tendons with knobs each connected to a respective one of the steering tendons and each sliding in a respective slot formed in a handle at a proximal end of the hollow body.

5. The method according to claim 1 , which further comprises providing the hollow body with an outer jacket and an inner sleeve, providing the tendons at least partly between the outer jacket and the inner sleeve, providing the corrugated tube between the outer jacket and the inner sleeve, and carrying out the step of applying suction between the outer jacket and the inner sleeve with a transitioning device for frictionally locking the tendons and the corrugated tube in place.

6. The method according to claim 5 , which further comprises providing a vacuum connection as the transitioning device, and actuating the vacuum connection with a valve at a handle of the hollow body.

7. The method according to claim 1 , which further comprises guiding the tendons with vertebrae disposed along the corrugated tube.

8. The method according to claim 7 , which further comprises placing the vertebrae between corrugation peaks of the corrugated tube for guiding the tendons.

9. The method according to claim 8 , which further comprises snapping the vertebrae onto the corrugated tube by elastically opening the vertebrae at a parting line into a gap.

10. The method according to claim 7 , which further comprises permitting movement of at least some of the tendons through channels formed in at least some of the vertebrae.

11. The method according to claim 1 , which further comprises attaching at least some of the tendons to a termination bushing at a distal end of the hollow body.

12. The method according to claim 11 , which further comprises forming each two of the tendons into legs of a U-shaped configuration passing through holes in the termination bushing and being interconnected by a crosspiece extending between two of the holes distally of the termination bushing.

13. The method according to claim 7 , which further comprises attaching some of the tendons to a termination bushing at a distal end of the hollow body as steering tendons, attaching others of the tendons to one of the vertebrae as non-steering tendons, and steering the distal end with the steering tendons.

14. The method according to claim 1 , which further comprises varying the number of the tendons along the hollow body for providing zones of varying stiffness.

15. The method according to claim 14 , which further comprises providing a greater number of the tendons toward a distal end than toward a proximal end of the hollow body, for increasing stiffness at the distal end.

16. The method according to claim 2 , which further comprises cuffing at least one end of the corrugated tube to prevent vacuum leakage.