WO2008119135A1

WO2008119135A1 - A surgical instrument

Info

Publication number: WO2008119135A1
Application number: PCT/AU2008/000477
Authority: WO
Inventors: Robert Herbert; Les E. Bokey; Volker Haberland; Sean Quigley
Original assignee: Vale Statutory & Mining Services Pty Limited; The University Of Sydney
Priority date: 2007-04-03
Filing date: 2008-04-03
Publication date: 2008-10-09

Abstract

The present application relates to a surgical instrument for use in minimally invasive surgery of a body. The instrument has: an elongate barrel having a first end that in use of the instrument is inserted through an opening in the body such that the barrel extends through the opening, and a second opposing end; a finger having one end that is pivotally mounted on the first end of the barrel, the finger being movable between a plurality of positions; and a drive mechanism for adjusting the position of the finger, the drive mechanism extending from the second end along the barrel and having a ratchet mechanism such that the finger can be selectively held in any one of the plurality of positions.

Description

A Surgical Instrument

Field of the invention

The present invention relates to a surgical instrument for use in minimally invasive surgery.

Background

Minimally invasive surgery involves surgical procedures on internal organs of a body by entering the body through the skin and/or an anatomical opening. By using small incisions, rather than a large incision, damage to the skin/anatomical opening is minimized.

Laparoscopic surgery is one form of minimally invasive surgery, which includes operations within the abdominal or pelvic cavity, and the thoracic or chest cavity. In laparoscopic surgical operations, the respective internal cavity is typically inflated using a gas, such as carbon dioxide. A camera and light source are passed through an opening in the body into the cavity. Real-time video images within the cavity are captured by the camera and displayed on a screen, such that the surgeon views the operation site on the screen. Various tools can be passed through other openings in the body, such that the surgeon can perform the operation on the body.

Minimally invasive surgery has many well documented benefits to the patient. However, there are many difficulties encountered by the surgeon when conducting an operation using minimally invasive surgical techniques. These include the difficulty in handling of the

N \Melbourne\cases\Patent\71000-71999\P7l759 PCT\Speci-\P7l759 PCT Specification 2008-4-3 doc 3/04/08 instruments and the lack of tactile perception for the surgeon .

The present invention has been developed in light of some of the difficulties that may be encountered during a minimally invasive surgical operation.

Summary of the invention The present invention provides a surgical instrument for use in minimally invasive surgery of a body, the instrument comprising: an elongate barrel having a first end that in use of the instrument is inserted through an opening in the body such that the barrel extends through the opening, and a second opposing end; a finger having one end that is pivotalIy mounted on the first end of the barrel, the finger being movable between a plurality of positions; and a drive mechanism for adjusting the position of the finger, the drive mechanism extending from the second end along the barrel and having a ratchet mechanism such that the finger can be selectively held in any one of the plurality of positions, whereby, in use of the instrument, the position of the finger is adjustable by the drive mechanism to draw tissue generally rearwardly toward the second end and provide a surface for supporting tissue to be cut by a cutting instrument.

Preferably, the plurality of positions includes a first position in which the finger is in line with the

H \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P71759 PCT Specification 2008-4-3 doc 3/04/08 barrel, and a second position in which the finger is inclined relative to the barrel.

In some embodiments, the plurality of positions further includes at least one intermediate position that is between the first and second positions.

The surgical instrument may have four intermediate positions .

In some embodiments, when the finger is in the second position, the finger is at right angles to the longitudinal direction of the barrel.

In certain embodiments, the first position, the at least one intermediate positions and the second position are spaced equiangularly in the range of movement of the finger.

The surgical instrument may further comprise a handle connected to the barrel adjacent the first end, and the drive mechanism can have a lever that is connected to the handle such that movement of the lever drives the finger between the first position, the second position, and the at least one intermediate position.

The ratchet mechanism may comprise a ratchet bar that is connected to the lever, and a pawl that is disposed within the body of the handle, the pawl having a tip that engages teeth on the ratchet bar.

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P7l759 PCT Specification 2008-4-3 doc 3/04/08 In some embodiments, the ratchet mechanism further comprises a spring that biases the pawl such that the tip is urged into engagement with the teeth.

The pawl may be pivotally connected within the handle and have an external end that protrudes from the handle, the external end being operable to disengage the tip from the ratchet bar.

In some embodiments, the drive mechanism comprises a pull rod that extends through the barrel, a first linkage that connects the lever to the pull rod, and a second linkage that connects the pull rod to the finger.

The surgical instrument may further comprise a spring disposed within the barrel, the spring providing a biasing force that urges the finger towards the first position. In some embodiments, the spring is provided between the first end of the barrel and the lever.

In certain embodiments, the finger comprises a base portion that is connected to the barrel by the pivot, and a tip portion that is releasably secured to the base portion. The tip portion may have a cavity and the base portion has a projection that can be received within the cavity. The finger can comprise a spring clip that releasably secures the projection within the cavity.

A top surface of the finger can be provided with a milled portion. The milled portion can have projections that are less than 0.5mm in height. The milled portion can have projections that are approximately 0.3mm in height .

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P71759 PCT Specification 2008-4-3 doc 3/04/08 The forward end of the finger can be provided with a notch that can co-operate with a cutting instrument to cut tissue.

In some embodiments, the finger further comprises a first finger portion that is mounted on the barrel and a second finger portion that is pivotally connected to the first finger portion.

A joint pivot mechanism can be provided, which operates to pivot the second finger portion relative to the first finger portion.

The joint pivot mechanism can be arranged to pivot the second finger portion in response to movement of the first finger portion relative to the barrel.

In some embodiments, the first and second finger portions are constrained to move in a common plane.

The joint pivot mechanism can be arranged to pivot the second finger portion proportionally to the inclination relative to the barrel of the first finger portion.

Brief description of the drawings

In order that the invention may be more easily understood, embodiments will now be described, by way of example only, in which:

N \Melbourne\cases\Patent\7l000-7l999\P7l759 PCT\Specis\P71759 PCT specification 2008-4-3 doc 3/04/08 Figure 1: is a cross sectional view of a surgical instrument in accordance with a first embodiment of the present invention; Figure 2 : is a cross sectional view of the surgical instrument of Figure 1, as seen along the line X-X in Figure 1; Figure 3 : is an enlarged cross sectional view of the handle of the surgical instrument of Figure

1; Figure 4 : is an enlarged cross sectional view of the handle of the surgical instrument of Figure

1 showing the lever in both released and fully depressed positions; Figure 5 : is a cross sectional view of the elongate barrel and finger of the surgical instrument of Figure 1; Figure 6 : is an enlarged cross sectional view of the cam mechanism of the surgical instrument of

Figure 1, with the finger in a straightened position; Figure 7 : is an enlarged cross sectional view of the cam mechanism of the surgical instrument of

Figure 1, with the finger in a fully rotated position; Figure 8: is a cross sectional view of the finger of the surgical instrument, showing the finger tip separated from the finger base; Figure 9: is a schematic top view of the finger tip of Figure 8 ; and Figure 10: is a cross sectional view of a finger tip of a surgical instrument in accordance with a second embodiment .

N \Melbourne\Cases\Patent\7l000-7l999\P7l759 PCT\Specis\P71759 PCT Specification 2008-4-3 doc 3/04/08 - 1 -

Detailed description

Figures 1 to 9 show a surgical instrument 10 according to a first embodiment of the present invention. The surgical instrument 10 has an elongate barrel 12, which, in use of the instrument 10, is inserted through a narrow aperture in the body (not shown) the procedure is being performed on. The barrel 12 has a finger 14 provided at a first (forward) end, and a handle 16 provided at the opposing second (rearward) end.

The finger 14 is connected to a pivot 18 that is mounted on a support 19 located on the forward end of the barrel 12. The finger 14 can rotate on the pivot 18 between a first position in which the finger 14 is in line with the barrel 12, and a second position in which the finger 14 is inclined to the barrel 12. The axis of rotation is indicated by broken line P-P in Figure 2. The first position is indicated by arrow A in Figure 1; the second position is indicated by arrow B in Figure 1. In the embodiment shown in Figures 1 to 9, the second position B is at right angles to the longitudinal direction of the barrel 12.

In use of the instrument 10, the finger 14 can be manipulated by the surgeon to draw tissue generally towards the second end of the barrel 12. The finger 14 can also provide a cutting surface for supporting tissue to be cut by a cutting instrument (not shown) .

The handle 16 has a body 20 and a palm-operated lever 22, which can be pivoted about a pin 24 within the body 20. In use, a surgeon operates the lever 22 by grasping

N

PCT speci fication 2008 -4 - 3 doc 3 /04 /08 the body 20 and a grip region 26 of the lever 22. Squeezing the grip region 26 of the lever 22 causes the lever 22 to rotate about the pin 24. Furthermore, squeezing the lever 22 causes the finger 14 to move towards the second position B, as will be discussed in further detail later.

A first upper arm 28 of the lever 22 is connected to a drive mechanism 30, which extends through the barrel 12. The drive mechanism 30 is connected to the finger 14.

Movement of the drive mechanism 30 effects movement of the finger 14 between the first and second positions A, B in response to movement of the lever 22.

A second upper arm 32 of the lever 22 abuts a compression spring 34, which is positioned in the second end of the barrel 12. The spring 34 is compressed between the second upper arm 32 and an end cap 35 on the barrel 12 as the lever 22 is squeezed. Accordingly, the surgeon has resistance to squeezing of the lever 22 and thus a positive feel for movement of the finger 14.

In this embodiment, the drive mechanism 30 has a rigid pull rod 36. The drive mechanism 30 also has a first linkage 38, which connects the pull rod 36 to the first upper arm 28 of the lever 22, and a second linkage 40, which connects the pull rod 36 to the finger 14. The first linkage 38 has pins 42a, 42b at each end that provide a rotational connection between the first upper arm 28 of the lever 22 and the first linkage 38, and the first linkage 38 and the pull rod 36. Similarly, the second linkage 40 has pins 44a, 44b at each end that provide a rotational connection between the pull rod 36

N \Melbourne\Cases\Patent\71000 71999\P71759 pcτ\specis\P71759 PCT Specification 2008-4-3 doc 3/04/08 and the second linkage 40, and the second linkage 40 and the finger 14.

Figures 1 and 4 show the position of the lever 22 in a fully released position (indicated by arrow R) , which corresponds with the finger 14 being in the first position A. In addition, Figures 1 and 4 show the position of the lever 22 in a fully depressed position (shown in broken lines and indicated by arrow D) , which corresponds with the finger being in the second position B.

Figure 6 shows the forward ends of the barrel 12 and the pull rod 36, the second linkage 40, the pivot 18 and the base of the finger 14. The pin 44b, which connects the second linkage 40 to the finger 14, is radially spaced from the axis P of the pivot 18. Movement of the pull rod 36 towards the second (rear) end of the barrel 12 causes the finger 14 to rotate about the axis P, such that the finger 14 moves towards the second position B, as shown in Figure 7. Conversely, movement of the pull rod 36 towards the forward end of the barrel 12 causes the finger 14 to rotate about the axis P such that the finger 14 moves towards the first position A, as shown in Figure 6.

As will be appreciated, movement of the lever 22 towards the fully depressed position D causes the pull rod 36 to move rearwardly within the barrel 12, thus causing the finger 14 to move toward the second position B. Conversely, movement of the lever 22 towards the fully released position R causes the pull rod 36 to move forwardly within the barrel 12, thus causing the finger 14 to move toward the first position A.

N \Melbourne\Cases\Patent\71000 -71999\P71759 PCT\Specis\P71759 PCT Specification 2008-4 - 3 doc 3/04 /08 The handle 16 is also provided with a ratchet mechanism 46, which allows the lever 22 to be selectively held in the fully released position R, the fully depressed position D, or any one of four intermediate positions between the fully released position R and the fully depressed position D. Accordingly, the finger 14 can be selectively held in the first position A, the second position B, and any one of four intermediate positions Ii , I₂, I₃, I₄. The four intermediate positions I₁, I₂, I3, I4 of the finger 14 are indicated in Figure 5.

In the present embodiment, the finger 14 can be selectively held in six distinct positions; that is, the first position A, the four intermediate positions Iχ , I₂, I₃, I₄, and the second position B. Each of the six distinct positions of the finger 14 are spaced equiangularly from the adjacent positions; that is, by an angular separation of 18°.

The ratchet mechanism 46 has a ratchet bar 48 located within the lever 22, and a spring-biased pawl 50 that is pivotally connected within the body 20 of the handle 16. An internal end 52 of the pawl 50 has a tip 53 that engages ratchet teeth 54 on the ratchet bar 48. An opposing external end 56 of the pawl 50 protrudes from the handle 16. In use of the instrument 10, the operator can press downwardly on the external end 56 of the pawl 50 to disengage the tip 52 from the ratchet teeth 54.

The ratchet mechanism 46 further includes a spring 58 and follower 60 that are mounted within a cavity 62 in the body 20 of the handle 16. The spring 58 is compressed between the follower 60 and the body 20 of the handle 16.

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P71759 PCT Specification 2008-4-3 doc 3/04/08 The spring 58 applies a force via the follower 60 to urge the internal end 52 of the pawl 50 toward the ratchet bar 48. Accordingly, the tip 53 is pushed into notches between the teeth on the ratchet bar 48.

In the present embodiment, the teeth on the ratchet bar 48 are arcuate, with steep side portions. Similarly, the notches between the teeth are also arcuate, with steep side portions. Due to the steep side portions of the teeth and notches of the ratchet bar 48, the tip 53 of the pawl 50 cannot readily be shifted across the teeth of the ratchet bar 48. Accordingly, to move the finger 14 between the first position A, the intermediate positions Ii , I₂, 1₃, I4 and/or the second position B, the external end 56 of the pawl 50 must first be operated to disengage the tip 53 from the teeth. Subsequently, the lever 22 can be moved to select the desired position of the finger 14.

In the embodiment shown in Figure 8, the finger 14 has a base portion 64 that has a through hole 66 that receives the pivot 18. A second through hole 68, which is spaced radially of the hole 66 and is parallel to the hole 66, receives the pin 44b of the second linkage 40. The finger 14 also has a tip portion 70 that can be readily interchanged if desired. The tip portion 70 has a cavity 72 that receives a projection 74 of the base portion 64 such that the tip portion 70 can be releasably attached to the base portion 64.

The cavity 72 has an annular recess 76 within which a spring clip 78 sits. The projection 74 has a corresponding annular recess 80. When the tip portion 70 is attached to the base portion 64 the spring clip 78 is

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT Specification 200B-4-3 doc 3/04/08 located in both the annular recesses 76, 80. The spring clip 78 co-operates with the annular recesses 76, 80 to provide a partial interference such that unintentional removal of the tip portion 70 from the base portion 64 is minimized. The tip portion 70 can be removed and replaced with alternative tip portions.

Figure 9 shows schematically a top view of the finger 14. Portions of the top surface of the base portion 64 and the tip portion 70 are provided with milled surfaces 82, 84, respectively. In one embodiment, the milled surfaces 82, 84 can be knurled, with projections and/or depressions of a height that is less than 0.5mm. The milled surfaces 82, 84 provide increased friction to facilitate drawing tissue generally towards the second (rearward) end of the barrel 12 as the position of the finger 14 is adjusted. In addition, the milled surfaces 82, 84 facilitate cutting tissue with a cutting instrument (not shown) as the friction between the tissue and the finger 14 inhibits sliding of the tissue along the finger 14.

As also shown in Figure 8, the forward end 86 of the tip portion 70 is provided with a notch 88. In use of the instrument 10, the notch 88 can be used in co-operation with a cutting instrument (not shown) to create a shearing action that facilitates cutting of tissue.

Figure 10 shows a tip portion 90 of a finger in accordance with an alternative embodiment. The tip portion 90 has a cavity 92 that receives a projection 74 of a base portion 64 of the finger 14 such that the tip

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P71759 PCT Specification 2008-4 3 doc 3/04/08 portion 90 can be releasably attached to the base portion 64.

The cavity 92 has an annular recess 96 within which a spring clip 98 sits. The projection of the base portion has a corresponding annular recess. When the tip portion 90 is attached to the base portion the spring clip 98 is seated in the annular recess on the projection, and the annular recess 96 within the cavity 92. The spring clip 98 co-operates with the annular recesses to provide an interference such that unintentional removal of the tip portion 90 from the base portion.

The top surface of the tip portion 90 can also be provided with milled surfaces (not shown) , as previously described.

As shown in Figure 10, the forward end 100 of the tip portion 90 is provided with a notch 102. In use of the instrument 10, the notch 102 can be used in co-operation with a cutting instrument (not shown) by establish a shearing action that facilitates cutting of tissue. The forward end 100 of the tip portion 90 has an oblique face such that the notch 102 is inclined towards the top surface of the finger.

It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the scope of the inventions.

For example, in some alternative embodiments the surgical instrument may be provided with a drive mechanism that has a cable instead of a rigid pull rod. In such an

N \Melbourne\Cases\Patent\71000-71999\P717S9 PCT\Specis\P71759 PCT Specification 2008-4-3 doc 3/04/08 embodiment, the cable extends between the lever and the second linkage. To control the position of the finger, the cable is maintained in tension by a spring located towards the first (forward) end of the barrel such that the spring is compressed as the second linkage is pulled by the cable towards the second (rearward) end of the barrel .

In certain embodiments, the teeth on the ratchet bar have a saw-tooth profile. The teeth may have a steep side and a ramped side; the teeth being arranged such that tip of the pawl can readily slide up the ramped side, but cannot slide up the steep side. In addition, the teeth may be orientated such that the finger can be incremented into or towards the second position B by squeezing the lever alone. However, to increment the finger into or towards the first position A, the tip of the pawl must be disengaged from the ratchet bar such that the tip can pass the respective tooth.

In some embodiments, the surgical instrument is provided with a selector mechanism that allows the finger to be incrementally advanced by one position, in either direction, by manipulation of one or more levers of the selector mechanism.

In some embodiments of the surgical instrument, the position of the barrel and/or the position of the finger relative to the barrel are electronically controlled. In such embodiments, electric motors are provided that drive mechanisms to adjust positions of the barrel/finger. In certain embodiments, the surgeon may have a control device

N \Melbourne\Cases\Patent\7l000 71999\P71759 PCT\Specia\P717S9 PCT specification 2008-4-3 doc 3/04/08 that allows remote control of the movement of the barrel and the finger.

In some embodiments of the surgical instrument, the finger can include a joint that connects a first finger portion with a second finger portion. The first finger portion is mounted on the forward end of the barrel. The second finger portion is supported by the joint.

In such embodiments, the surgical instrument further comprises a joint pivot mechanism that operates to pivot the second finger portion relative to the first finger portion. The joint pivot mechanism can be arranged to pivot the second finger portion in response to movement of the first finger portion relative to the barrel.

The first and second finger portions can be constrained to move in a common plane. This can further facilitate drawing tissue generally towards the second (rearward) end of the barrel.

In certain embodiments, the joint pivot mechanism further operates to pivot the second finger proportionally with respect to the inclination of the first finger portion relative to the barrel. In other words, when the finger is in a position in which the first finger portion is in line with the barrel, the second finger portion is in line with the first finger portion. When the first finger portion is inclined relative to the barrel, the second finger portion is pivoted by the joint pivot mechanism relative to the first finger portion.

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P71759 PCT Specification 2008-4-3 doc 3/04/08 In some embodiments, when the first finger portion is inclined at an angle of 45° to the barrel, the second finger portion is inclined at an angle of 45° to the first finger portion and, hence, at an angle of 90° to the barrel. In some alternative embodiments, when the first finger portion is inclined at an angle of 90° to the barrel, the second finger portion is inclined at an angle of 45° to the first finger portion and, hence, at an angle of 135° to the barrel.

The joint pivot mechanism can be in the form of a tendon that has one end in connection with the drive mechanism of the instrument and the other end is connected to the second finger portion. The tendon passes around the pivot on the opposing side of the pivot to the pin that connects the first finger portion with the drive mechanism. Thus, retraction of the drive mechanism in the barrel causes an increase in inclination of the first finger portion relative to the barrel. The tendon causes the second finger portion to pivot proportionally to the inclination relative to the barrel of the first finger portion.

It will be appreciated that the joint pivot mechanism may be provided in alternative forms.

Alternatively, the joint pivot mechanism can be arranged to pivot the second finger portion independently of the first finger portion.

In the claims which follow and in the preceding description of the invention, except where the context

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P7l759 PCT specification 2008-4-3 doc 3/04/08 requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

N \Melbourne\Cases\Patent\71000-7l999\P71759 PCT\Specis\P7l759 PCT Specification 2008 -4 - 3 doc 3/04 /08

Claims

CLAIMS :

1. A surgical instrument for use in minimally- invasive surgery of a body, the instrument comprising: an elongate barrel having a first end that in use of the instrument is inserted through an opening in the body such that the barrel extends through the opening, and a second opposing end; a finger having one end that is pivotalIy mounted on the first end of the barrel, the finger being movable between a plurality of positions; and a drive mechanism for adjusting the position of the finger, the drive mechanism extending from the second end along the barrel and having a ratchet mechanism such that the finger can be selectively held in any one of the plurality of positions, whereby, in use of the instrument, the position of the finger is adjustable by the drive mechanism to draw tissue generally rearwardly toward the second end and provide a surface for supporting tissue to be cut by a cutting instrument.

2. A surgical instrument according to claim 1, wherein the plurality of positions includes a first position in which the finger is in line with the barrel, and a second position in which the finger is inclined relative to the barrel.

3. A surgical instrument according to claim 2, wherein the plurality of positions further includes at least one intermediate position that is between the first and second positions.

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P7l759 PCT specification 2008-4-3 doc 3/04/08

4. A surgical instrument according to claim 3, wherein the at least one intermediate position comprises four intermediate positions .

5. A surgical instrument according to either claim 3 or 4, wherein the first position, the at least one intermediate positions and the second position are spaced equiangularIy in the range of movement of the finger.

6. A surgical instrument according to any one of claims 2 to 5, wherein when the finger is in the second position, the finger is at right angles to the longitudinal direction of the barrel .

7. A surgical instrument according to any one of claims 1 to 6 , further comprising a handle connected to the barrel adjacent the first end, and the drive mechanism includes a lever that is connected to the handle such that movement of the lever drives the finger between the plurality of positions.

8. A surgical instrument according to claim 7, wherein the ratchet mechanism comprises a ratchet bar that is connected to the lever, and a pawl that is disposed within the body of the handle, the pawl having a tip that engages teeth on the ratchet bar.

9. A surgical instrument according to claim 8, wherein the ratchet mechanism further comprises a spring that biases the pawl such that the tip is urged into engagement with the teeth.

N \Melbourne\Cases\Patent\71000-7l999\P71759 PCT\Specis\P71759.PCT Specification 2008-4-3.doc 3/04/08

10. A surgical instrument according to either claim 8 or 9, wherein the pawl is pivotally connected within the handle and has an external end that protrudes from the handle, the external end being operable to disengage the tip from the ratchet bar.

11. A surgical instrument according to any one of claims 7 to 10, wherein the drive mechanism comprises a pull rod that extends through the barrel, a first linkage that connects the lever to the pull rod, and a second linkage that connects the pull rod to the finger.

12. A surgical instrument according to any one of claims 1 to 11, further comprising a spring disposed within the barrel, the spring providing a biasing force that urges the finger towards the first position.

13. A surgical instrument according to any one of claims 1 to 12, wherein the finger comprises a base portion that is connected to the barrel by the pivot, and a tip portion that is releasably secured to the base portion.

14. A surgical instrument according to any one of claims 1 to 13, wherein a top surface of the finger is provided with a milled portion.

15. A surgical instrument according to claim 14, wherein the milled portion has projections that are less than 0.5mm in height.

16. A surgical instrument according to any one of claims 1 to 15, wherein the forward end of the finger is

N \Melbourne\Cases\Patent\71000-71999\P71759 PCT\Specis\P71759 PCT Specification 2008-4-3 doc 3/04/08 provided with a notch that can co-operate with a cutting instrument to cut tissue.

17. A surgical instrument according to any one of claims 1 to 16, wherein the finger further comprises a first finger portion that is mounted on the barrel and a second finger portion that is pivotally connected to the first finger portion.

18. A surgical instrument according to claim 17, further comprising a joint pivot mechanism that operates to pivot the second finger portion relative to the first finger portion.

19. A surgical instrument according to claim 18, wherein the joint pivot mechanism is arranged to pivot the second finger portion in response to movement of the first finger portion relative to the barrel.

20. A surgical instrument according to either claim 18 or 19, wherein the first and second finger portions are constrained to move in a common plane.

21. A surgical instrument according to any one of claims 18 to 20, wherein the joint pivot mechanism is arranged to pivot the second finger portion proportionally to the inclination relative to the barrel of the first finger portion.

N \Melbourne\Cases\Patent\71000-7l999\P71759 PCT Specification 2008-4-3 doc 3/04/08