Surgical tools for use in minimally invasive telesurgical applications

• US 6,394,998 B1
• Filed: 09/17/1999
• Issued: 05/28/2002
• Est. Priority Date: 01/22/1999
• Status: Expired due to Term

• Current Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Original Assignee: Intuitive Surgical Incorporated (Intuitive Surgical Holdings, LLC)
• Inventors: Wallace, Daniel T., Morley, Tracey A., Julian, Christopher A., Baron, David S.
• Primary Examiner(s): Cohen, Lee
• Assistant Examiner(s): RAM, JOCELYN D
• Application Number:
  US09/398,958
• Time in Patent Office: 984 Days
• Field of Search: 606/1,167,208 74/490.05,490.06 901/15,28,29,39
• US Class Current: 606/1
• CPC Class Codes: A61B 17/00234 for minimally invasive surgery A61B17/0218, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence
• CPC Class Codes: A61B 2017/00477 Coupling A61B2017/0046 takes precedence
• CPC Class Codes: A61B 2034/305 Details of wrist mechanisms at distal ends of robotic arms
• CPC Class Codes: A61B 2034/715 Cable tensioning mechanisms for removing slack
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: A61B 34/35 for telesurgery
• CPC Class Codes: A61B 34/71 Manipulators operated by drive cable mechanisms
• CPC Class Codes: Y10T 74/20335 Wrist

Abstract

This invention provides surgical tools or instruments for use in minimally invasive telesurgical applications. The instruments typically include a base whereby the instrument is removably mountable on a robotically controlled articulated arm. An elongate shaft extends from the base. A working end of the shaft is disposed at an end of the shaft remote from the base. A wrist member is pivotally mounted on the working end. At least one end effector element mounting formation is pivotally mounted on an opposed end of the wrist member. A plurality of elongate elements, e.g., cables, extend from the end effector element mounting formation and the wrist member to cause selective angular displacement of the wrist member and end effector mounting formation in response to selective pulling of the elongate elements.

Claims

1. A minimally invasive surgical instrument comprising:

an elongate shaft having a working end;

a wrist member having an end portion pivotally mounted on the working end of the shaft;

a first mounting formation pivotally mounted to an opposed end portion of the wrist member;

a pair of first elongate elements, each of the pair extending from a respective one of two opposed positions on the mounting formation and in a direction toward a proximal end of the shaft;

a first driving member, the first elongate elements being coupled to the first driving member so as to cause angular displacement of the mounting formation in one angular direction in response to the first driving member causing one of the first elongate elements to be pulled and to cause angular displacement of the mounting formation in an opposed angular direction in response to the first driving member causing the other first elongate element to be pulled;

a pair of second elongate elements, each of the pair extending from a respective one of two opposed positions on the wrist member and in a direction toward the proximal end of the shaft; and

a second driving member, the second elongate elements being coupled to the second driving member so as to cause the wrist member to pivot in one angular direction in response to the second driving member causing one of the second elongate elements to be pulled, and to cause the wrist member to pivot in an opposed angular direction in response to the second driving member causing the other second elongate element to be pulled.

2. The surgical instrument of claim 1, further comprising:

a second mounting formation;

a pair of third elongate elements, each of the pair extending from a respective one of two opposed positions on the second mounting formation and in a direction toward the proximal end of the shaft;

a third driving member, the third elongate elements being coupled to the third driving member so as to cause the second mounting formation to displace in one angular direction in response to the third driving member causing one of the third elongate elements to be pulled and to displace in an opposed angular direction in response to the third driving member causing the other third elongate element to be pulled.

3. A minimally invasive surgical instrument comprising:

an elongate shaft having a working end;

a wrist member having an end portion pivotally mounted on the working end of the shaft;

a first mounting formation for an end effector element pivotally mounted to an opposed end portion of the wrist member;

a first elongate element extending from the mounting formation and in a direction toward a proximal end of the shaft, the first elongate element being coupled to an actuator so as to cause angular displacement of the mounting formation in one angular direction in response to the actuator exerting a force on the elongate element and to cause angular displacement. of the mounting formation in an opposed angular direction in response to the actuator exerting a counterforce on the elongate element; and

a second elongate element extending from the wrist member and in a direction toward the opposed end of the shaft, the second elongate element being coupled to a second actuator so as to cause the wrist member to pivot in one angular direction in response to the second actuator exerting a second force on the second elongate element, and to cause the wrist member to pivot in an opposed angular direction in response to the second actuator exerting a second counterforce on the second element.

4. The surgical instrument of claim 3, further comprising:

a second mounting formation; and

a third elongate element extending from said second mounting formation and in a direction toward the proximal end of the shaft, said third elongate element coupled to yet a further actuator so as to cause the second mounting formation to displace in one angular direction in response to the further actuator exerting a third force on the third elongate element and to displace in an opposed angular direction in response to the further actuator exerting a third counterforce on the third elongate element.

14. A surgical instrument as in claim 4, in which the at least one mounting-formation-moving elongate element comprises a first elongate element and a second elongate element, wherein:

the first elongate element extends from the at least one mounting formation at a position on one side of the axis about which the mounting formation is angularly displacable relative to the wrist member; and

the second elongate element extends from the at least one mounting formation at a position on an opposed side of the axis about which the mounting formation is angularly displacable relative to the wrist member.

15. A surgical instrument as in claim 14, in which the first and the second elongate elements are operatively connected to the second drive member so that:

when the second drive member is displaced in the one direction relative to the shaft, the first elongate element is caused to be pulled relative to the mounting formation thereby to cause the mounting formation to be displaced angularly in the one direction relative to the wrist member; and

when the second drive member is displaced in the opposed direction relative to the shaft, the second elongate element is caused to be pulled relative to the mounting formation thereby to cause the mounting formation to be displaced angularly in the opposed direction relative to the wrist member.

16. A surgical instrument as in claim 15, in which the second drive member is mounted toward the proximal end of the shaft so as to be angularly displacable relative to the shaft about a third axis, such that:

when the second drive member displaces in one angular direction relative to the shaft about the third axis, the first elongate element is caused to be pulled relative to the mounting formation; and

when the second drive member displaces in an opposed angular direction relative to the shaft about the third axis, the second elongate element is caused to be pulled relative to the mounting formation.

17. A surgical instrument as in claim 16, in which at least the second drive member is in the form of a spool or drum mounted for rotation about the axis.

18. A surgical instrument as in claim 16, in which the first and second elongate elements are defined by opposed portions of a single elongate element.

19. A surgical instrument as in claim 16, in which the first and second elongate elements are at least partially formed from a length of cable.

20. A surgical instrument as in claim 19, in which the at least one mounting formation comprises a circumferentially extending channel and the length of cable rides along at least part of the circumferentially extending channel.

21. A surgical instrument as in claim 16, in which the first and second elongate elements are at least partially formed from at least one length of cable and at least one hypotube portion, wherein an end portion of the at least one length of cable is secured to an end portion of the at least one hypotube portion.

22. A surgical instrument as in claim 16, in which the shaft defines an internal longitudinally extending passage and the at least one elongate element extends at leas partially internally along the shaft in the passage.

29. A surgical instrument as in claim 18, in which the third drive member is mounted toward the proximal end of the shaft so as to be angularly displacable relative to the shaft about a third axis, such that:

when the third drive member displaces in one angular direction relative to the shaft about the third axis, the first further elongate element is caused to be pulled relative to the second mounting formation; and

when the third drive member displaces in an opposed angular direction relative to the shaft about the third axis, the second further elongate element is caused to be pulled relative to the second mounting formation.

30. A surgical instrument as in claim 29, in which the third drive member is in the form of a spool or drum mounted for rotation about the third axis.

31. A surgical instrument as in claim 29, in which the first and second further elongate elements are defined by opposed portions of a single elongate element.

32. A surgical instrument as in claim 29, in which the first and second further elongate elements are at least partially formed from a length of cable.

33. A surgical instrument as in claim 32, in which the at least one mounting formation comprises a circumferentially extending channel and the length of cable rides along at least part of the circumferentially extending channel.

34. A surgical instrument as in claim 29, in which the first and second further elongate elements are at least partially formed from at least one length of cable and at least one hypotube portion, wherein an end portion of the at least one length of cable is secured to an end portion of the at least one hypotube portion.

5. A surgical instrument comprising:

an elongate shaft defining a proximal end and a distal end;

a wrist member mounted toward the distal end of the elongate shaft to be angularly displacable relative to the shaft about a first axis;

at least one end effector mounting formation mounted on the wrist member to be angularly displacable relative to the wrist member about a second axis;

a first drive member operatively mounted toward the proximal end of the shaft;

at least one wrist-member-moving elongate element operatively connected between the first drive member and the wrist member so as;

to cause the wrist member to be displaced angularly in one direction relative to the shaft in response to the first drive member being displaced in one direction relative to the shaft; and

to cause the wrist member to be displaced angularly in an opposed direction relative to the shaft in response to the first drive member being displaced in an opposed direction relative to the shaft;

a second drive member operatively mounted toward the proximal end of the shaft; and

at least one mounting-formation-moving elongate element operatively connected between the second drive member and the at least one mounting formation so as;

to cause the mounting formation to be displaced angularly in one direction relative to the wrist member in response to the second drive member being displaced in one direction relative to the shaft; and

to cause the mounting formation to be displaced angularly in an opposed direction relative to the wrist member in response to the second drive member being displaced in an opposed direction relative to the shaft.

6. A surgical instrument as in claim 5, in which the at least one wrist-member-moving elongate element comprises a first elongate element and a second elongate element;

the first elongate element extending from the wrist member at a position on one side of the axis about which the wrist member is angularly displacable relative to the shaft; and

the second elongate element extending from the wrist member at a position on an opposed side of the axis about which the wrist member is angularly displacable relative to the shaft.

7. A surgical instrument as in claim 6, in which the first and the second elongate elements are operatively connected to the first drive member so that:

when the first drive member is displaced in the one direction relative to the shaft, the first elongate element is caused to be pulled relative to the wrist member thereby to cause the wrist member to be displaced angularly in the one direction relative to the shaft; and

when the first drive member is displaced in the opposed direction relative to the shaft, the second elongate element is caused to be pulled relative to the wrist member thereby to cause the wrist member to be displaced angularly in the opposed direction relative to the shaft.

8. A surgical instrument as if in claim 7, in which the first drive member is mounted toward the proximal end of the shaft so as to be angularly displacable relative to the shaft about a third axis, such that:

when the first drive member displaces in one angular direction relative to the shaft about the third axis, the first elongate element is caused to be pulled relative to the wrist member; and

when the first drive member displaces in an opposed angular direction relative to the shaft about the third axis, the second elongate element is caused to be pulled relative to the wrist member.

9. A surgical instrument as claimed in claim 8, in which at least the first drive member is in the form of a spool or drum mounted for rotation about the axis.

10. A surgical instrument as in claim 8, in which the first and second elongate elements are defined by opposed portions of a single elongate element.

11. A surgical instrument as in claim 8, in which the first and second elongate elements are at least partially formed from a length of cable.

12. A surgical instrument as in claim 8, in which the first and second elongate elements are at least partially formed from at least one length of cable and at least one hypo tubeportion, wherein an end portion of the at least one length of cable is secured to an end portion of the at least one hypotube portion.

13. A surgical instrument as in claim 8, in which the shaft defines an internal longitudinally extending passage and the at least one elongate element extends at least partially internally along the shaft.

23. A surgical instrument as in claim 5, in which the at least one mounting formation comprises a first mounting formation and a second mounting formation.

24. A surgical instrument as in claim 23, in which each of the first and second mounting formations is mounted on the wrist member to be angularly displacable relative to the wrist member about an axis.

25. A surgical instrument as in claim 24, in which the second mounting formation is mounted on the wrist member to be angularly displacable relative to the wrist member about the same axis as the first mounting formation.

26. A surgical instrument as in claim 24, which further comprises

a third drive member operatively mounted at the proximal end of the shaft;

and

at least one further mounting-formation-moving elongate element operatively connected between the third drive member and the second mounting formation so as;

to cause the second mounting formation to be displaced angularly in one direction relative to the wrist member in response to the third drive member being displaced in one direction relative to the shaft and

to cause the second mounting formation to be displaced angularly in an opposed direction relative to the wrist member in response to the third drive member being displaced in an opposed direction relative to the shaft.

27. A surgical instrument as in claim 26, in which the at least one further mounting-formation-moving elongate element comprises a first further elongate element and a second further elongate element, wherein:

the first further elongate element extends from the second mounting formation at a position on one side of the axis about which the second mounting formation is angularly displacable relative to the wrist member and

the second further elongate element extends from the second mounting formation at a position on an opposed side of the axis about which the second mounting formation is angularly displacable relative to the wrist member.

28. A surgical instrument as in claim 27, in which the first and the second further elongate elements are operatively connected to the third drive member so that:

when the third drive member is displaced in the one direction relative to the shaft, the first further elongate element is caused to be pulled relative to the second mounting formation thereby to cause the second mounting formation to be displaced angularly in the one direction relative to the wrist member; and

when the third drive member is displaced in the opposed direction relative to the shaft, the second further elongate element is caused to be pulled relative to the second mounting formation thereby to cause the second mounting formation to be displaced angularly in the opposed direction relative to the wrist member.

35. A surgical instrument as in claim 23, wherein each mounting formation has an end effector connected thereto, and each end effector is connected to each mounting formation removably.

36. A surgical instrument as in claim 5, wherein the mounting formation has an end effector connected thereto.

37. A surgical instrument as in claim 36, wherein the end effector is connected to the mounting formation removably.

38. A surgical instrument as in claim 5, wherein the axis about which the wrist member is angularly displacable relative to the shaft and the axis about which the at least one mounting formation is angularly displacable relative to the wrist member are spaced apart and extend along generally parallel planes.

39. A surgical instrument as in claim 38, wherein the axes are non-parallel.

40. A surgical instrument as in claim 39, in which the axes are generally perpendicular relative to each other.

41. The surgical instrument of claim 5, the surgical instrument being for use with a robotic surgical system having first and second instrument actuators, wherein the first drive member is drivingly couplable with the first instrument actuator of the robotic system, and wherein the second drive member is drivingly couplable with the second instrument actuator of the robotic system.

42. A surgical instrument comprising:

an elongate shaft defining a proximal end and a distal end;

a wrist member mounted toward the distal end of the elongate shaft to be angularly displacable relative to the shaft about a first axis;

at least one end effector mounting formation mounted on the wrist member to be angularly displacable relative to the wrist member about a second axis;

a first drive member operatively mounted toward the proximal end of the shaft;

at least one wrist-member-moving elongate element operatively connected between the first drive member and the wrist member so as to cause the wrist member to be displaced angularly in one direction relative to the shaft in response to the first drive member being displaced in one direction relative to the shaft, and to cause the wrist member to be displaced angularly in an opposed direction relative to the shaft in response to the first drive member being displaced in an opposed direction relative to the shaft;

a) the at least one wrist-member-moving elongate element comprising a first elongate element and a second elongate element, the first elongate element extending from the wrist member at a position on one side of the axis about which the wrist member is angularly displacable relative to the shaft, and the second elongate element extending from the wrist member at a position on an opposed side of the axis about which the wrist member is angularly displacable relative to the shaft;

b) the first and the second elongate elements being operatively connected to the first drive member so that when the first drive member is displaced in the one direction relative to the shaft, the first elongate element is caused to be pulled relative to the wrist member thereby to cause the wrist member to be displaced angularly in the one direction relative to the shaft, and when the first drive member is displaced in the opposed direction relative to the shaft, the second elongate element is caused to be pulled relative to the wrist member thereby to cause the wrist member to be displaced angularly in the opposed direction relative to the shaft;

c) the first drive member being angularly displacable relative to the shaft about a third axis, such that when the first drive member displaces in one angular direction relative to the shaft about the third axis, the first elongate element is caused to be pulled relative to the wrist member, and when the first drive member displaces in an opposed angular direction relative to the shaft about the axis, the second elongate element is caused to be pulled relative to the wrist member; and

d) the first and second elongate elements being at least partially formed from at least one hypotube portion and opposed lengths of cable extending from opposed end portions of the hypotube portion, the one length of cable being wrapped about the drive member and the other length of cable being operatively connected to the wrist member;

a second drive member operatively mounted toward the proximal end of the shaft; and

at least one mounting-formation-moving elongate element operatively connected between the second drive member and the at least one mounting formation so as to cause the mounting formation to be displaced angularly in one direction relative to the wrist member in response to the second drive member being displaced in one direction relative to the shaft, and to cause the mounting formation to be displaced angularly in an opposed direction relative to the wrist member in response to the second drive member being displaced in an opposed direction relative to the shaft.

43. A surgical instrument comprising:

an elongate shaft defining a proximal end and a distal end;

a wrist member mounted toward the distal end of the elongate shaft to be angularly displacable relative to the shaft about a first axis;

at least one end effector mounting formation mounted on the wrist member to be angularly displacable relative to the wrist member about a second axis;

a first drive member operatively mounted toward the proximal end of the shaft;

at least one wrist-member-moving elongate element operatively connected between the first drive member and the wrist member so as to cause the wrist member to be displaced angularly in one direction relative to the shaft in response to the first drive member being displaced in one direction relative to the shaft, and to cause the wrist member to be displaced angularly in an opposed direction relative to the shaft in response to the first drive member being displaced in an opposed direction relative to the shaft;

a second drive member operatively mounted toward the proximal end of the shaft; and

at least one mounting-formation-moving elongate element operatively connected between the second drive member and the at least one mounting formation so as to cause the mounting formation to be displaced angularly in-one direction relative to the wrist member in response to the second drive member being displaced in one direction relative to the shaft, and to cause the mounting formation to be displaced angularly in an opposed direction relative to the wrist member in response to the second drive member being displaced in an opposed direction relative to the shaft;

a) the at least one mounting-formation-moving elongate element comprising a first elongate element and a second elongate element, wherein the first elongate element extends from the at least one mounting formation at a position on one side of the axis about which the mounting formation is angularly displacable relative to the wrist member, and the second elongate element extends from the at least one mounting formation at a position on an opposed side of the axis about which the mounting formation is angularly displacable relative to the wrist member;

b) the first and the second elongate elements being operatively connected to the second drive member so that when the second drive member is displaced in the one direction relative to the shaft, the first elongate element is caused to be pulled relative to the mounting formation thereby to cause the mounting formation to be displaced angularly in the one direction relative to the wrist member, and when the second drive member is displaced in the opposed direction relative to the shaft, the second elongate element is caused to be pulled relative to the mounting formation thereby to cause the mounting formation to be displaced angularly in the opposed direction relative to the wrist member;

c) the second drive member being angularly displacable relative to the shaft about a third axis, such that when the second drive member displaces in one angular direction relative to the shaft about the third axis, the first elongate element is caused to be pulled relative to the mounting formation; and

when the second drive member displaces in an opposed angular direction relative to the shaft about the axis, the second elongate element is caused to be pulled relative to the mounting formation;

d) the first and second elongate elements being at least partially formed from at least one hypotube portion and opposed lengths of cable extending from opposed end portions of the hypotube portion, the one length of cable being wrapped about the second drive member and the other length of cable being operatively connected to the mounting formation.

44. A surgical instrument comprising:

a) an elongate shaft defining a proximal end and a distal end;

b) a wrist member mounted toward the distal end of the elongate shaft to be angularly displacable relative to the shaft about a first axis;

c) at least one end effector mounting formation mounted on the wrist member to be angularly displacable relative to the wrist member about a second axis;

d) a first drive member operatively mounted toward the proximal end of the shaft;

e) at least one wrist-member-moving elongate element operatively connected between the first drive member and the wrist member so as to cause the wrist member to be displaced angularly in one direction relative to the shaft in response to the first drive member being displaced in one direction relative to the shaft, and to cause the wrist member to be displaced angularly in an opposed direction relative to the shaft in response to the first drive member being displaced in an opposed direction relative to the shaft;

f) a second drive member operatively mounted toward the proximal end of the shaft;

g) at least one mounting-formation-moving elongate element operatively connected between the second drive member and the at least one mounting formation so as to cause the mounting formation to be displaced angularly in one direction relative to the wrist member in response to the second drive member being displaced in one direction relative to the shaft, and to cause the mounting formation to be displaced angularly in an opposed direction relative to the wrist member in response to the second drive member being displaced in an opposed direction relative to the shaft;

the at least one mounting formation comprising a first mounting formation and a second mounting formation, and each of the first and second mounting formations being mounted on the wrist member to be angularly displacable relative to the wrist member about the second axis;

h) a third drive member operatively mounted at the other end of the shaft; and

i) at least one further mounting-formation-moving elongate element operatively connected between the third drive member and the second mounting formation so as to cause the second mounting formation to be displaced angularly in one direction relative to the wrist member in response to the third drive member being displaced in one direction relative to the shaft, and to cause the second mounting formation to be displaced angularly in an opposed direction relative to the wrist member in response to the third drive member being displaced in an opposed direction relative to the shaft;

the at least one further mounting-formation-moving elongate element comprising a first further elongate element and a second further elongate element, wherein the first further elongate element extends from the second mounting formation at a position on one side of the axis about which the second mounting formation is angularly displacable relative to the wrist member, and the second further elongate element extends from the second mounting formation at a position on an opposed side of the axis about which the second mounting formation is angularly displacable relative to the wrist member;

the first and the second further elongate elements being operatively connected to the third drive member so that when the third drive member is displaced in the one direction relative to the shaft, the first further elongate element is caused to be pulled relative to the second mounting formation thereby to cause the second mounting formation to be displaced angularly in the one direction relative to the wrist member, and when the third drive member is displaced in the opposed direction relative to the shaft, the second further elongate element is caused to be pulled relative to the second mounting formation thereby to cause the second mounting formation to be displaced angularly in the opposed direction relative to the wrist member;

the third drive member being mounted toward the proximal end of the shaft so as to be angularly displacable relative to the shaft about a third axis, such that when the third drive member displaces in one angular direction relative to the shaft about the third axis, the first further elongate element is caused to be pulled relative to the second mounting formation, and when the third drive member displaces in an opposed angular direction relative to the shaft about the third axis, the second further elongate element is caused to be pulled relative to the second mounting formation;

the first and second further elongate elements being at least partially formed from at least one hypotube portion and opposed lengths of cable extending from opposed end portions of the hypotube portion, the one length of cable being wrapped about the third drive member and the other length of cable being operatively connected to the second mounting formation.

45. A surgical instrument comprising:

a) an elongate shaft defining a proximal end and a distal end;

b) a wrist member mounted toward the distal end of the elongate shaft to be angularly displacable relative to the shaft about a first axis;

c) at least one end effector mounting formation mounted on the wrist member to be angularly displacable relative to the wrist member about a second axis;

d) a first drive member operatively mounted toward the proximal end of the shaft;

e) at least one wrist-member-moving elongate element operatively connected between the first drive member and the wrist member so as to cause the wrist member to be displaced angularly in one direction relative to the shaft in response to the first drive member being displaced in one direction relative to the shaft, and to cause the wrist member to be displaced angularly in an opposed direction relative to the shaft in response to the first drive member being displaced in an opposed direction relative to the shaft;

f) a second drive member operatively mounted toward the proximal end of the shaft;

g) at least one mounting-formation-moving elongate element operatively connected between the second drive member and the at least one mounting formation so as to cause the mounting formation to be displaced angularly in one direction relative to the wrist member in response to the second drive member being displaced in one direction relative to the shaft, and to cause the mounting formation to be displaced angularly in an opposed direction relative to the wrist member in response to the second drive member being displaced in an opposed direction relative to the shaft;

the at least one mounting formation comprising a first mounting formation and a second mounting formation, and each of the first and second mounting formations being mounted on the wrist member to be angularly displacable relative to the wrist member about the second axis;

h) a third drive member operatively mounted at the other end of the shaft; and

i) at least one further mounting-formation-moving elongate element operatively connected between the third drive member and the second mounting formation so as to cause the second mounting formation to be displaced angularly in one direction relative to the wrist member in response to the third drive member being displaced in one direction relative to the shaft, and to cause the second mounting formation to be displaced angularly in an opposed direction relative to the wrist member in response to the third drive member being displaced in an opposed direction relative to the shaft;

the at least one further mounting-formation-moving elongate element comprising a first further elongate element and a second further elongate element, wherein the first further elongate element extends from the second mounting formation at a position on one side of the axis about which the second mounting formation is angularly displacable relative to the wrist member, and the second further elongate element extends from the second mounting formation at a position on an opposed side of the axis about which the second mounting formation is angularly displacable relative to the wrist member;

the first and the second further elongate elements being operatively connected to the third drive member so that when the third drive member is displaced in the one direction relative to the shaft, the first further elongate element is caused to be pulled relative to the second mounting formation thereby to cause the second mounting formation to be displaced angularly in the one direction relative to the wrist member, and when the third drive member is displaced in the opposed direction relative to the shaft, the second further elongate element is caused to be pulled relative to the second mounting formation thereby to cause the second mounting formation to be displaced angularly in the opposed direction relative to the wrist member;

the third drive member being mounted toward the proximal end of the shaft so as to be angularly displacable relative to the shaft about a third axis, such that when the third drive member displaces in one angular direction relative to the shaft about the third axis, the first further elongate element is caused to be pulled relative to the second mounting formation, and when the third drive member displaces in an opposed angular direction relative to the shaft about the third axis, the second further elongate element is caused to be pulled relative to the second mounting formation;

the shaft defining an internal longitudinally extending passage and the at least one hypotube portion extending at least partially internally along the shaft in the passage.