Method for variably flexing and steering an insertion device

1. A method for variably flexing and steering an insertion device that receives an instrument, which comprises:

providing a hollow body having:

tendons disposed therewithin; and

a distal end;

changing a condition of the hollow body by selectively:

applying suction to create a vacuum in the hollow body to place the hollow body in a relatively stiff condition; and

relieving the vacuum to place the hollow body in a relatively flexible condition;

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

individually adjusting at least one of the tendons in length to steer the distal end of the hollow body.

2. The method according to claim 1 , which further comprises providing a handle at a proximal end of the hollow body, the tendons being free to move longitudinally within the handle.

3. The method according to claim 2 , wherein the tendons float in the handle when the hollow body is in the relatively flexible condition.

4. The method according to claim 1 , which further comprises carrying out the step of individually adjusting at least one of the tendons with at least one knob, the at least one knob being connected to the at least one adjustable tendon and sliding in a slot formed in a handle of 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; and

carrying out the step of applying suction by applying suction between the outer jacket and the inner sleeve with a transitioning device.

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 , wherein the hollow body has:

an outer jacket;

an inner sleeve;

a proximal end; and

a handle at the proximal end having an outer handle and an inner handle defining a vacuum plenum volume therebetween communicating between the outer jacket and the inner sleeve.

8. The method according to claim 7 , which further comprises:

providing a vacuum port in communication with the vacuum plenum volume; and

carrying out the step of applying suction between the outer jacket and the inner sleeve with the vacuum port.

9. The method according to claim 1 , which further comprises guiding the tendons with at least one vertebra disposed within the hollow body.

10. The method according to claim 9 , which further comprises permitting movement of at least one of the tendons through at least one channel formed in the at least one vertebra.

11. The method according to claim 9 , which further comprises providing a termination bushing at the distal end of the hollow body to which at least some of the tendons are attached.

12. The method according to claim 9 , which further comprises:

attaching the at least one adjustable tendon to a termination bushing at the distal end of the hollow body;

attaching others of the tendons to the at least one vertebra; and

steering the distal end with the at least one adjustable tendon.

13. The method according to claim 1 , wherein the tendons slide in the relatively flexible and relatively stiff conditions.

14. The method according to claim 1 , which further comprises varying a number of the tendons disposed within the hollow body to provide zones of varying stiffness of the hollow body.

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

16. The method according to claim 1 , wherein the tendons are neither in tension nor compression when the hollow body is in the relatively stiff condition.

17. The method according to claim 1 , wherein the tendons are not under tension in both the relatively flexible and relatively stiff conditions.