Motion feedthrough

1. A motion feedthrough for a surgical drape, the motion feedthrough comprising:

a drive transfer element comprising a first portion and a second portion, the first portion being releasably engageable with a portion of a terminal link of a robot arm and the second portion being releasably engageable with a portion of an instrument, the drive transfer element being linearly movable relative to a bulk portion of the drape so as to transfer drive between the robot arm and the instrument, wherein the drive transfer element is linearly movable in a direction substantially parallel to a longitudinal axis of the terminal link of the robot arm.

2. A motion feedthrough as claimed in claim 1 , in which the motion feedthrough is operable to transfer drive without compromising the integrity of the surgical drape.

3. A motion feedthrough as claimed in claim 1 , in which the motion feedthrough is configured to substantially close a hole in the drape and/or be attachable to the periphery of a hole in the drape so as to maintain a substantially hermetic sterile barrier.

4. A motion feedthrough as claimed in claim 1 , in which the motion feedthrough comprises a first longitudinally extending element and a second longitudinally extending element, the first and second longitudinally extending elements being slidingly engageable with one another along at least a portion of their length.

5. A motion feedthrough as claimed in claim 4 , in which the first longitudinally extending element comprises a tongue and the second longitudinally extending element comprises a groove, the tongue being engagingly receivable within the groove.

6. A motion feedthrough as claimed in claim 4 , in which at least one of the first and the second longitudinally extending elements comprises a recess for receiving a plug.

7. A motion feedthrough as claimed in claim 4 , in which at least one of the first longitudinally extending element and the second longitudinally extending element is attachable to the periphery of a hole in the drape, so that at least a portion of the drape will move together with the respective longitudinally extending element.

8. A motion feedthrough as claimed in claim 1 , in which the motion feedthrough comprises a pair of capture members defining therebetween a capture portion for slidably capturing a portion of the drape.

9. A motion feedthrough as claimed in claim 8 , in which the capture members comprise one or more of a low-friction material and rollers.

10. A motion feedthrough as claimed in claim 1 , in which the motion feedthrough comprises three capture members defining between a first capture member and a second capture member a first capture portion, and defining between the second capture member and a third capture member a second capture portion, the first capture portion and the second capture portion being for slidably capturing a portion of the drape.

11. A motion feedthrough as claimed in claim 1 , in which the motion feedthrough comprises a plurality of drive transfer elements, the drive transfer elements being linearly movable.

12. A motion feedthrough as claimed in claim 1 , in which the plurality of drive transfer elements are movable parallel to one another.

13. A motion feedthrough as claimed in claim 1 , in which paths defined by movement of each drive transfer element are non-overlapping in a direction transverse to a direction of movement of at least one drive transfer element.

14. A motion feedthrough as claimed in claim 1 , in which paths defined by movement of each drive transfer element at least partially overlap in a direction transverse to a direction of movement of at least one drive transfer element.

15. A motion feedthrough as claimed in claim 1 , in which paths defined by movement of each drive transfer element are aligned along a common line.

16. A motion feedthrough as claimed in claim 1 , in which the motion feedthrough extends generally in a plane, and the drive transfer element is linearly movable in the plane.