WO2005086564A2

WO2005086564A2 - Surgical instrument

Info

Publication number: WO2005086564A2
Application number: PCT/GB2005/000852
Authority: WO
Inventors: Robert William Sawyer; Ronald William Lockyer
Original assignee: Tissue Science Laboratories Plc
Priority date: 2004-03-13
Filing date: 2005-03-07
Publication date: 2005-09-22
Also published as: WO2005086564A3

Abstract

A surgical instrument comprises an olive, the olive being connectable to a tunnelling rod and being adapted for attachment of an implant, wherein the olive is provided with a longitudinal slot therein. At least a portion of the longitudinal slot opens along its length at a longitudinal opening at a first side of the olive, a first end of which slot opens at a first end of the olive. The longitudinal slot is operative to securely and releasably engage a distal end portion of the tunnelling rod.

Description

SURGICAL INSTRUMENT The present invention relates to a surgical instrument and, more particularly, to a surgical instrument for use in a new procedure for the correction of procto graphic abnormalities. A number of conditions are known to affect the colon, rectum and anus.

More serious conditions require treatment by surgical intervention. Intussusception is a condition in which part of the bowel telescopes in on itself, and can result in bowel obstruction. A rectocele occurs when the rectum bulges into the vagina. Intussusception and rectocele often occur together. At present, an obstructing intrarectal intussusception may be corrected by abdominal rectopexy. However, this major open abdominal surgical procedure often achieves poor results in practice. Mobilisation of the rectum may lead to denervation of the rectum and may cause angulation of the sigmoid on the rectum, which in turn exacerbates the evacuatory difficulty. In addition, the open abdominal procedure is invasive and is associated with a serious risk of complications. We have developed a new surgical procedure for the correction of intrarectal intussusception. The new procedure is reasonably minimally invasive and can easily be combined with rectocele repair in cases where patients present with both conditions. Briefly, the new procedure has been carried out as follows. A perineal incision is made. If the right side is to be repaired first, then a trochar point is attached to a tunnelling rod by screwing onto a fine screw thread

and inserted into the soft tissue just to the right of the midline and pushed superiorly and laterally to exit at a position on the right lateral inferior aspect of the abdomen through a previously prepared short incision. The trochar point is then removed and an olive with a suture hole is attached by screwing onto the fine screw thread. A suitable implant is then sutured to the olive via the suture hole and the whole assembly comprising the tunnelling rod, olive and implant is drawn back through the tunnel formed in the soft tissue until the implant is correctly positioned at the anterior wall of the rectum, where it is sutured in place. The suture between implant and olive is then cut and the instrument is removed. The olive is detached from the tunnelling rod and the trochar reattached in order that the procedure may be repeated for the left side. The implants are then tensioned and sutured in place by suturing to the periosteum of the pubis. If necessary, a further implant may be introduced and sutured in position to repair a rectocele. The new procedure is reasonably minimally invasive and is therefore preferred to abdominal rectopexy. In preliminary studies, the procedure has been carried out using a Medtronic instrument (product no. 3550-06). However, this instrument is intended for use for placement of tunnelling leads for electrodes for other Medtronic equipment and is not ideally suited to the new procedure for correction of intrarectal intussusception. For example, with the existing instrument, the attachment of the trochar and olive to the shaft of the tunnelling rod is achieved by screwing onto a relatively fine screw thread, and is therefore somewhat awkward and time-consuming. An object of the present invention is to provide a surgical instrument better suited for use in the newly developed procedure. According to a first aspect of the present invention therefore there is provided a surgical instrument comprising an olive, the olive being connectable to a tunnelling rod and being adapted for attachment of an implant, wherein the olive is provided with a longitudinal slot therein, at least a portion of which slot opens along its length at a first side of the olive and one end of which slot opens at a first end of the olive, said slot being operative to securely and releasably engage a distal end portion of the tunnelling rod. With this arrangement, the olive may be relatively quickly and easily connected to the tunnelling rod, and subsequently released, without the need for awkward and time-consuming screwing onto a screw thread, the distal end portion of the tunnelling rod being securely accommodated within the slot and subsequently releasable therefrom. It will be appreciated that this has advantages for use of the surgical instrument according to this aspect of the present invention in the newly developed procedure for surgical correction of intussusception, during which the olive must be secured to and released from the tunnelling rod a number of times. The surgical instrument according to this aspect of the present invention may find use in a range of surgical procedures. The surgical instrument according to this aspect of the present invention may be used in the correction of full thickness rectal prolapse. It is to be understood that a tunnelling rod as referred to herein may comprise any instrument or tool suitable for use in creating a soft tissue tunnel, such as a borer, or suitable for use in tunnelling through a pre-formed soft tissue tunnel. Thus, the tunnelling rod may have a sharpened distal tip to facilitate creation of a new soft tissue tunnel, or may alternatively have a blunt distal tip for use in tunnelling through a pre-formed soft tissue tunnel where a sharpened tip is unnecessary. Typically, the tunnelling rod comprises an elongate, generally cylindrical, shaft, in which case the longitudinal slot is operative to engage the distal end portion of the shaft which, when engaged, lies within the slot, the remainder of the shaft extending out from the open end of said slot at the first end of the olive. The olive may be adapted for attachment of an implant by, for example, suturing. The olive may therefore be adapted to receive a suture by means of which the implant may be attached to the olive. A hole in or through part of the olive may be provided for this purpose. The hole may be situated at or towards a second end of the olive opposite the first end. The longitudinal slot may take any appropriate form. It will be appreciated that the dimensions of the slot, and in particular its width in the transverse direction, may vary according to the diameter of the tunnelling rod in order to ensure secure engagement of the distal end portion of said tunnelling rod within the slot. The depth of the slot will typically be at least as great as the diameter of the distal end portion of the tunnelling rod, and is preferably greater than said diameter. An interference fit between the distal end portion of the tunnelling rod and the longitudinal slot is preferably established when the distal end portion of the tunnelling rod is engaged by the slot. Preferably, the slot is generally straight in the longitudinal direction, the

corresponding distal end portion of the tunnelling rod typically being generally straight. In profile, the slot may be generally straight-sided and may have a generally U-shaped cross-section, although other configurations are possible. The slot, or at least part of the slot, may be wider in the transverse direction at or towards its longitudinal closed side, i.e. the part of the slot furthest from the longitudinal opening, than at the longitudinal opening. The width of the slot at or towards the longitudinal opening thereof may be less than the diameter of the distal end portion of the tunnelling rod to be engaged by the slot whereas the width of the slot at or towards the longitudinal closed side may be substantially equal to or greater than the diameter of the tunnelling rod. An interference fit between the distal end portion of the tunnelling rod and the longitudinal slot is preferably established when the distal end portion of the tunnelling rod is engaged by the slot. Preferably, therefore, the difference in width of the slot at or towards the longitudinal opening and at or towards the longitudinal closed side is small. Preferably also, the width of the slot at or towards the longitudinal opening is only slightly less than the diameter of the distal end portion of the tunnelling rod, whereby a user may, by applying a relatively low level of force by hand, push the distal end portion of the tunnelling rod into the slot such that the distal end portion of the tunnelling rod passes through the relatively narrow part of the slot and into the wider part of the slot at or towards the longitudinal closed side for secure engagement thereby. This arrangement provides a "snap-fit" mechanism for attachment of the olive to the tunnelling rod, which may be released by applying force in the opposite direction to pull the distal end portion of the tunnelling rod from the slot. It will be appreciated, therefore, that the width of the slot at or towards the longitudinal opening is preferably sufficiently great to allow the distal end portion of the tunnelling rod to pass therethrough upon application of force by hand in the direction of the closed longitudinal side of the slot by a user of the instrument, and sufficiently small such that subsequent passive exit of the distal end portion of the tunnelling rod is resisted once said distal end portion of said tunnelling rod has been engaged within the wider part of the slot at or towards the longitudinal closed side. Preferably, an interference fit is established. Most preferably, the slot is generally straight-sided at or towards its longitudinal opening, and opposing sides of the slot may be substantially parallel. Preferably also, the slot widens at its longitudinal closed side in the form of a generally cylindrical longitudinal bore, said bore being of greater diameter than the distance between the straight sides of the slot. Preferably, the diameter of the bore substantially corresponds to the diameter of the distal end portion of the tunnelling rod, which typically takes the form of a generally cylindrical elongate shaft. The width of the straight-sided part of the slot at or towards the longitudinal opening should be sufficiently great to allow the distal end portion of the tunnelling rod to pass therethrough upon application of force in the direction of the closed longitudinal side of the slot by hand by a user of the instrument, and sufficiently small such that subsequent passive exit of the distal end portion of the tunnelling rod from the slot is resisted. Thus, the distal end portion of the tunnelling rod may be securely engaged within the longitudinal bore defining the longitudinal closed side of the slot and is releasable therefrom upon application of

force in the reverse direction, i.e. away from the closed longitudinal side of the slot. Advantageously, the "snap-fit" mechanism provided by this arrangement may produce an audible sound as the distal end portion of the tunnelling rod is pushed into the longitudinal slot of the olive, indicating to a user of the instrument that the tunnelling rod has been securely engaged by the olive. The diameter of the longitudinal slot may be smaller towards a first end of the slot at the first end of the olive than at a second, opposite, end of the slot remote from the open first end. The distal end portion of the tunnelling rod may, correspondingly, be of greater diameter at or towards its distal tip than at a more proximal part of said distal end portion, such that the distal tip may be accommodated within the wider part of the slot towards the second end of the slot but is wider than the part of longitudinal slot towards the first end of the slot which part in use accommodates the more proximal part of the distal end portion of the tunnelling rod. With this arrangement, when the distal end portion of the tunnelling rod is engaged within the longitudinal slot of the olive, escape of the distal end portion of the tunnelling rod from the olive in the longitudinal direction, from the open first end of the longitudinal slot, is prevented since the distal tip is unable to pass through the narrower part of the longitudinal slot. The size and shape of the longitudinal slot at the part towards the second end of the slot may correspond generally to the shape of the distal tip of the tunnelling rod. Thus, the shape of the longitudinal slot may vary according to the shape of the distal tip of the tunnelling rod. The distal tip of the tunnelling rod may widen in a step, such that a shouldered arrangement is provided. Similarly, the longitudinal slot may widen in a step, such that a corresponding shouldered arrangement is provided.

The remainder of the tunnelling rod, i.e. the part more proximal than the distal end portion to be engaged within the longitudinal slot, may be of any width or diameter. The olive according to this aspect of the present invention may take any suitable form. It will be appreciated that the particular dimensions and shape of the olive may vary according to the nature of the procedure in which it is to be employed. In the case of surgical correction of intussusception, a problem noted with the prior art instrument hereinbefore described is that the olive is shaped such that in use it is considerably easier to push it superiorly (upwards) than it is to pull it inferiorly (downwards). Thus, the existing instrument is not well suited for use in the newly developed surgical procedure for correction of intussusception, in which there is requirement for the olive to be pulled inferiorly through the soft tissue of the patient. In view of this, the instrument according to the first aspect of the present invention preferably comprises an olive shaped in such a way as to be relatively easy to draw inferiorly through the soft tissue once attached to the tunnelling rod. The olive may therefore taper inwards in one or more dimensions towards its first end, said first end being the proximal end in use. If desired, the olive may also taper inwards in one or more dimensions towards a second end opposite the first end, whereby the olive is widest at or towards a central portion thereof. The olive may therefore narrow towards either or both ends in the general direction of either or both of y or z axes of the olive, an x axis thereof being the longitudinal axis, the y axis being the transverse axis and the z axis being perpendicular to both x and y axes. The olive is therefore preferably streamlined for travel through a soft tissue tunnel. The olive should be sized according to the requirements of the surgical procedure in which it is to be used. For example, in the case of surgical correction of intussusception, the olive is preferably sufficiently wide such that when it is attached to the tunnelling rod and drawn back through the soft tissue tunnel, the olive creates space within the soft tissue tunnel to facilitate the passage through the tunnel of the implant attached to the olive. The olive may be widest in either the y (transverse) or z direction. The olive may be formed from any suitable material. For example, the olive may be formed from a plastics material, for example a polyethylene. The olive may be formed in any appropriate manner. For example, the olive may be machined or moulded. In a preferred embodiment of this aspect of the present invention, a hole extends through the olive between the first side of the olive and a second side opposite the first side, wherein the longitudinal slot has a first longitudinal opening at the first side of the olive continuous with the hole and extending from said hole to the first end of the olive and a second longitudinal opening at the second side of the olive continuous with the hole and extending from the hole towards a second end of the olive opposite the first end. This arrangement is especially advantageous in that it greatly facilitates engagement of the distal end of the tunnelling rod within the longitudinal slot. In use, a distal tip of the tunnelling rod may be passed through the hole in the olive from the first side of the olive until it just emerges at the second side of the olive, whereupon the olive may be rotated relative to the tunnelling rod such that the first side and first end of the olive move towards the tunnelling rod. The rotational movement is continued until the distal end portion has been engaged within the longitudinal slot of the olive. The distal tip of the tunnelling rod is moved into the slot via the second longitudinal opening, whilst a more proximal part of the distal end portion of the tunnelling rod is moved into engagement within the slot via the first longitudinal opening. The hole may be of greater width in the transverse direction than the part of the longitudinal slot opening at the first longitudinal opening. The part of the longitudinal slot opening at the second longitudinal opening may be wider in the y (transverse) and/or z direction than the part of the longitudinal slot opening at the first longitudinal opening. With this arrangement, the distal tip of a tunnelling rod having a distal tip that is wider than a more proximal part of the distal end portion and wider than the part of the longitudinal slot opening at the first longitudinal opening is unable to pass through said part of the longitudinal slot in the longitudinal direction. The second longitudinal opening may be wider in the transverse direction than the first longitudinal opening, whereby the distal tip of a tunnelling rod having a distal tip that is wider than a more proximal part of the distal end portion of the tunnelling rod may be moved into engagement within the longitudinal slot via the second longitudinal slot, whilst the relatively narrow part of the distal end portion of the tunnelling rod is moved into engagement within the slot via the first longitudinal opening. The surgical instrument according to this aspect of the present invention may further comprise a tunnelling rod. With regard to the tunnelling rod, this may take any suitable form. The tunnelling rod may, for example, comprise a borer. Preferably, the tunnelling rod comprises an elongate shaft. The elongate shaft may, for example, be generally cylindrical and may be of any suitable length and diameter. It has been noted, however, that the prior art instrument used in preliminary studies has a tendency to bend in use, its shaft being relatively small in diameter. Preferably, therefore, the tunnelling rod has a relatively thick elongate shaft, the diameter being, for example, 4mm or above, for example 4-8mm. Such a tunnelling rod has less tendency to bend in use than the existing instrument. It will be appreciated that a range of different shaft lengths may be employed. The tunnelling rod may be formed from any material suitable for surgical instruments. Typically, the tunnelling rod comprises an elongate shaft formed from a metal, such as steel, for example stainless steel 316L. The tunnelling rod may be provided with a proximal handle for ease of use. Any suitable handle may be provided, and this may be fixed to the elongate shaft in any appropriate manner. The handle should preferably provide good grip to a user and may therefore be sized and shaped accordingly. The handle may be formed from any suitable material, such as, for example, a plastics material. The tunnelling rod may be provided with a sharpened distal tip to facilitate creation of a soft tissue tunnel. The distal tip may be formed into a point. The tunnelling rod may be provided with a trochar point at its distal tip. In one preferred embodiment, the trochar point is fixed at the distal tip. This arrangement overcomes a problem noted with the existing instrument hereinbefore discussed, namely the requirement for awkward and time-consuming attachment

and removal of the trochar point during the surgical procedure for correction of intussusception. In this aspect of the present invention, the trochar point may be formed integrally with the distal end portion of the tunnelling rod. Where the surgical instrument according to this aspect of the present invention is to be used in the surgical correction of full thickness rectal prolapse, a sharpened distal tip of the tunnelling rod is preferred. Advantageously, the sharpened distal tip facilitates tunnelling through subcutaneous tissue in this procedure. Alternatively, the tunnelling rod may have a blunt distal tip. For example, the distal tip may be domed, i.e. generally hemispherical. Advantageously, the blunt-ended tunnelling rod allows for relatively easy connection of the olive thereto during use of the surgical instrument in procedures not requiring a sharpened distal tip. Significant care and attention is required when handling sharpened instruments during surgery, and the absence of a sharpened distal tip therefore facilitates manipulation of the surgical instrument. A blunt-ended tunnelling rod may be employed for use in the new surgical procedure for intrarectal intussusception described herein, the tunnelling rod being inserted through a pre-formed soft tissue tunnel. The soft tissue tunnel may be formed, for example, by dissection of a plane between the posterior wall of the vagina and the anterior wall of the rectum. The tunnelling rod is preferably of greater diameter at or towards the distal tip thereof than at a more proximal part of the distal end portion. A distal trochar point or domed tip may be provided, the trochar point or domed tip having a diameter greater than the more proximal part of the distal end portion of a shaft to which it is fixed. The distal tip of the tunnelling rod may have a proximal surface generally at right angles to the more proximal part of the distal end portion of the

tunnelling rod, forming a shoulder. Where the tunnelling rod comprises an elongate shaft of generally uniform diameter, the distal tip may be of greater diameter than the elongate shaft. Alternatively, the distal end portion of the tunnelling rod may comprise a distal tip and a more proximal part, the more proximal part being of a smaller diameter than the distal tip and of smaller diameter than a more proximal part of a shaft comprising the remainder of the tunnelling rod. In such a case, the diameter of the distal tip may be less than, equal to or greater than the diameter of the more proximal part of the shaft comprising the remainder of the tunnelling rod, but is typically greater than or equal to the diameter of the more proximal part of the shaft comprising the remainder of the tunnelling rod. The tunnelling rod may comprise a generally straight elongate shaft. Indeed, for some procedures, a straight shaft may be most appropriate. A straight- shafted instrument may be preferred, for example, if the instrument is to be used in the surgical correction of full thickness rectal prolapse. However, the size and shape of the tunnelling rod may be varied according to the particular requirements of the surgical procedure in question. Advantageously, for use in correction of intrarectal intussusception, in the presence or absence of rectocele, the tunnelling rod may comprise a curved elongate shaft. The curved shaft facilitates correct passage of the tunnelling rod through the soft tissue tunnel created between the perineal incision and the short abdominal incision. Most preferably, where the tunnelling rod comprises a curved shaft, the

distal end portion of the shaft is generally straight such that it may be readily engaged by an olive having a generally straight longitudinal slot. Thus, the shaft of the tunnelling rod may be curved proximally to the distal end portion. This aspect of the present invention provides a surgical instrument that is useful in the correction of proctographic abnormalities. The olive may be connected to the tunnelling rod relatively quickly and easily. Conveniently, however, the surgical instrument may further comprise an olive holding device operative to facilitate handling of the olive and connection of said olive to the tunnelling rod. The olive holding device is adapted for releasable engagement of the olive and may take any suitable form. For example, the olive holding device may comprise a member having a slot or channel therein in which to accommodate the olive to be held thereby. Importantly, the longitudinal slot of the olive remains accessible when the olive is engaged by the olive holding device. In a particularly preferred embodiment, the olive holding device comprises a member having a generally C-shaped longitudinal channel opening at a first side of the member. The channel also opens at a first end of the member. Preferably, the channel is at least partially closed at a second end of the member, opposite the first end, relative to said first end. The channel is sized and shaped to receive the olive, which may be slid into engagement within said channel via the open end of the channel. The olive is accommodated within the channel such that first side of the olive, and thus the longitudinal slot of the olive a portion of which slot opens along its length at said first side of the olive, is accessible via the longitudinal opening of the channel in the member. Once engaged within the olive holding device, the olive may be more easily manipulated. This may be particularly beneficial where a sharp ended tunnelling rod is used, since the use of the olive holding device will reduce the risk of injury to a user of the instrument from the sharpened tip of the tunnelling rod. The olive may be connected to the distal end portion of the tunnelling rod as hereinbefore described, the longitudinal slot of the olive being accessible to said tunnelling rod. The channel is preferably shaped to allow the distal tip of the tunnelling rod to pass through a hole between the first and second sides of the olive to just emerge at the second side of the olive before being moved into the longitudinal slot of the olive via a second longitudinal opening at the second side of the olive. The olive holding device may be formed from any suitable material, such as a plastics material. The olive holding device may have flexible and/or movable walls, which may be flexed and/or moved when the olive is accommodated within the channel of the olive holding device in order to more firmly grip said olive in place within the channel. Conveniently, the olive holding device may comprise a member having a generally C-shaped longitudinal channel opening at a first side of the olive holding device and having opposing walls either side of the channel, wherein the walls are provided with respective longitudinal slots therethrough adjacent the channel, the slots extending from the first end of the olive holding device and being closed at their ends remote from said first end of the olive holding device, which slots allow the walls of the olive holding device, and consequently the walls of the channel, to be urged towards one another. In use, therefore, the olive may be slid into engagement within the channel of the olive holding device and the walls of said olive holding device urged towards one another such that the olive is more tightly gripped by contact with the walls of the U-shaped channel. The side walls of the olive holding device may be provided with means for improving handling and grip of the device, for example ribs which may run longitudinally. A further preferred feature of the olive holding device is that the longitudinal channel has a second opening at its second end narrower than a first opening at the first end, whereby the olive is unable to pass through the second end of the olive holding device, only being able to move into and out of engagement within the channel via the opening at the first end of the olive holding device, but the second end of the channel is accessible to the tunnelling rod. This may be achieved by providing an olive holding device having a channel the walls of which taper inwards in the transverse direction towards the second end of the olive holding device, wherein both first and second ends of the olive holding device are open, the opening at the second end being small enough to restrict passage of the olive and at the same time larger than the diameter of the tunnelling rod. With this arrangement, the olive may be introduced into the channel of the olive holding device in either orientation, i.e. first end first or second end first, and in either orientation the distal end of the tunnelling rod may be engaged within the longitudinal slot of the olive in the manner hereinbefore described, such that once the olive and tunnelling rod have been connected the tunnelling rod extends from the first end of the longitudinal slot in the olive and out of one or other of the ends of the channel in the olive holding device. It may be preferable in use to infroduce the olive into the olive holding device first end first, whereby the first end of the olive is adjacent the second end of the olive holding device when engaged therein. The tunnelling rod will typically be pointed generally upwards following the initial part of the surgical procedure where it is passed through the soft tissue runnel to emerge from the short abdominal incision. Engagement of the olive within the channel of the olive holding device such that the first end of the olive is adjacent to the second, partially closed, end of the channel, ensures that the olive cannot fall from the olive holding device when positioned for connection to the distal end of the tunnelling rod, i.e. with the first end of the olive pointing generally downwards. Once the olive has been connected to the tunnelling rod, the olive may be disengaged from the channel of the olive holding device by sliding out of the open first end of the channel. Where the olive is engaged within the channel of the olive holding device such that the first end of the olive is adjacent to the second end of the channel, removal of the olive from the olive holding device will require the olive holding device to be slid towards the patient until the olive emerges completely from engagement. With regard to the implant, this may comprise any implant suitable for the procedure to be carried out using the surgical instrument according to this aspect of the present invention. It will be appreciated that the implant may be sized and shaped according to the requirements of the procedure in question. It has been found that the surgical correction of intussusception may be carried out effectively using coUagenous implant materials, for example the materials described in US 5397535. Such coUagenous materials are particularly well suited for use in the new surgical procedure, being substantially non- resorbable and substantially non-antigenic. These coUagenous materials are strong and retain their original size and shape. The coUagenous materials provide a support matrix for the ingrowth of new tissue, cells and blood vessels following implantation. The coUagenous materials have been shown to perform better than synthetic implant materials (British Journal of Surgery (2003) 90 (Supp. 1) 138 (82)). The shape of the implant will largely depend upon the nature of the defect to be treated or corrected by its implantation. For use in the correction of intussusception, the implant may be generally T-shaped, this shape having been found to be particularly suitable. The crossbar of the 'T' provides for good fixation onto the bowel to distribute load whilst the stem of the 'T' facilitates its positioning within the abdominal space with minimal disturbance to surrounding soft tissue. A rectocele may be repaired using a generally rectangular implant, which may be provided with tabs at opposite ends to facilitate placement and suturing of the implant. Any or all of the olive, tunnelling rod and implant may, if desired, be presented in sterilised form. Sterilisation may be carried out in any conventional manner, for example by gamma irradiation. According to a second aspect of the present invention there is provided a surgical kit comprising a surgical instrument according to the first aspect of the invention and an implant. The invention will now be described further with reference to and as illustrated in the accompanying non-limiting drawings, in which:

Fig. 1 is a diagrammatic perspective view of one embodiment of a surgical instrument according to an aspect of the present invention showing the olive and tunnelling rod; Fig. 2 is a diagrammatic side view of the tunnelling rod as shown in Fig. 1; Fig. 3 is a diagrammatic side view of a tunnelling rod according to an alternative embodiment, in which the tunnelling rod is shown (a) with a distal trochar point and (b) with a domed distal tip; Fig. 4 is a diagrammatic underplan view of the first side of the olive as shown in Fig. 1; Fig. 5 is a diagrammatic plan view of the second side of the olive as shown in Figs. 1 and 4; Fig. 6 is a diagrammatic longitudinal cross-sectional view of the olive as shown in Figs. 1, 4 and 5;

Fig. 7 is a diagrammatic end view of the first end of the olive as shown in Figs. 1 and 4-6; Fig. 8 is a diagrammatic representation depicting a use of one embodiment of a surgical instrument according to an aspect of the present invention;

Fig. 9 is a diagrammatic side view of an olive holding device according to an aspect of the present invention; Fig. 10 is a diagrammatic underplan view of the olive holding device of Fig. 9 showing the first side thereof; Fig. 11 is a diagrammatic longitudinal cross-sectional view of the olive holding device of Figs. 9 and 10 along the line X-X of Fig. 10; Fig. 12 is a diagrammatic end view of the olive holding device of Figs. 9- 11 showing the first end thereof; Fig. 13 is a diagrammatic end view of the olive holding device of Figs. 9- 12 showing the second end thereof; and Fig. 14 is a diagrammatic perspective view of the olive holding device of Figs. 9-13. With reference to Fig. 1, a surgical instrument 10 comprises an olive 11 and a tunnelling rod 12, said olive 11 being connectable to said tunnelling rod 12. As shown in Figs. 1 and 2, the tunnelling rod 12 comprises an elongate shaft 13 and a handle 14 fixed thereto. The elongate shaft 13 is generally cylindrical and has a fixed frochar point 16 at its distal tip. The diameter of the trochar point 16 is greater than the diameter of the more proximal part of the distal end portion 17 of the elongate shaft 13. The proximal surface of the trochar point 16 extends generally at right angles to the more proximal part of the distal end portion 17 of the elongate shaft 13. The elongate shaft 13 may be formed from stainless steel 316L. The handle 14 may be formed from a plastics material, for example ultra high molecular weight polyethylene. The handle 14 is sized and shaped for ease of handling by a user of the instrument 10. Figs. 3a and 3b show a tunnelling rod 12 according to an alternative embodiment. In contrast to the tunnelling rod 12 of Figs. 1 and 2, which are generally straight shafted, the tunnelling rod 12 of Figs. 3a and 3b has a curved shaft 13. By way of example, the shaft 13 may be approximately 400mm long and the distal end portion may be offset from the straight by around 35mm. The distal end portion 17 of the shaft 12

is nevertheless generally straight. In Fig. 3 a, the tunnelling rod 12 has a fixed trochar point 16 at its distal tip, the diameter of the trochar point 16 being greater than the diameter of the more proximal part of the distal end portion 17 of the elongate shaft 13. The diameter of the more proximal part of the distal end portion 17 is smaller than the more proximal part of the elongate shaft 13. In contrast, the tunnelling rod of Fig. 3b has a domed, generally hemispherical, distal tip 18, although the other features of the tunnelling rod are as shown in Fig. 3a. The diameter of the domed distal tip 18 is greater than the diameter of the more proximal part of the distal end portion 17 of the elongate shaft 13. The type of tunnelling rod 12 chosen for use will depend upon the nature of the procedure to be carried out. A curved tunnelling rod 12 such as that shown in Figs. 3a and 3b is preferred for use in surgical correction of intrarectal intussusception. The blunt- ended curved tunnelling rod 12 of Fig. 3b is particularly preferred for use in this new procedure. Referring now to Figs. 4 to 7, the olive 11, formed from a plastics material, such as ultra high molecular weight polyethylene, has opposite first 21 and second 22 sides and opposite first 23 and second 24 ends. The olive 11 tapers inwards towards its first 23 and second 24 ends in the y (transverse) direction and in the z direction (i.e. between the first 21 and second 22 sides). The olive 11 has curved edges and is relatively wide in the transverse direction compared to the z direction. The olive 11 is more streamlined when viewed from the first end 23 than from the second end 24, the widest part of the olive 11 in the transverse direction being closer to the second end 24 than to the first end 23. In use, therefore, the olive 11 presents a low degree of resistance to movement through soft tissue when pulled with the first end 23 towards the direction of movement as compared to the degree of resistance to movement when pushed with the second end 24 towards the direction of movement. The olive 11 is provided with a longitudinal slot 26 operative to securely and releasably engage the distal end 17 of a tunnelling rod 12 by interference fit. A generally cylindrical hole 27, of diameter at least as great as the diameter of the distal trochar point 16, or domed distal tip 18, of the tunnelling rod 12, extends through the olive 11 between the first 21 and second 22 sides of the olive 11, the hole 27 being situated closer towards the first end 23 than the second end 24 of the olive 11. The longitudinal slot 26 has a first longitudinal opening 28 at the first side 21 of the olive 11 continuous with the hole 27 and extending from said hole 27 to the first end 23 of the olive, and a second longitudinal opening 29 at the second side 22 of the olive continuous with the hole 27 and extending from said hole 27 in the direction of the second end 24 of the olive 11. The longitudinal slot 26 is generally straight in the longitudinal direction. The longitudinal slot 26 comprises a generally cylindrical bore 30 through the olive 11 running generally along the longitudinal axis of the olive 11 from an open end 31 of the longitudinal slot 26 at the first end 23 of the olive 11 to a closed end 32 towards the second end 24 of the olive and generally straight-sided portions communicating the cylindrical bore 30 with the first longitudinal opening 28 at the first side 21 of the olive 11 and with the second longitudinal opening 29 at the second side 22 of the olive 11. The opposing sides of the generally straight-sided portions of the longitudinal slot 26 are generally parallel to one another. The longitudinal slot is wider in at least the y (transverse) direction at the part of the slot 26 between the hole 27 and the closed end 32 than at the part of the slot between the hole 27 and the open end 31. The first longitudinal opening 28 is narrower in the transverse direction than the hole 27. The second longitudinal opening 29 is wider in the transverse direction than the first longitudinal opening 28, and may be of approximately the same width in the transverse direction as the hole 27. The part of the longitudinal slot 26 between the hole 27 and the closed end 32 is mainly of slightly greater diameter than the distal trochar point 16, or domed distal part 18, of the tunnelling rod 12. The part of the longitudinal slot 26 between the hole 27 and the open end 31 formed by the cylindrical bore 30 is of approximately the same diameter as the more proximal part of the distal end portion 17 of the tunnelling rod 12. The diameter of the generally cylindrical bore 30 between the hole 27 and the open end 31 of the longitudinal slot 26 is slightly greater than the width in the transverse direction of the generally straight-sided portion of the longitudinal slot 26 defined by opposing generally parallel walls 33 and 34 and opening at the first longitudinal opening 28 of the longitudinal slot 26. The olive 11 provided with a suture hole 36 between the first 21 and second 22 sides towards the second end 24 of the olive 11. The suture hole 36 is generally cylindrical and functions to facilitate the attachment of an implant to the olive 11 by suturing. The surgical instrument 10, or a component thereof, may be presented sterile, and may therefore be packaged accordingly. Fig. 8 shows an example of the use of one embodiment of a surgical instrument according to an aspect of the present invention in a newly developed surgical procedure for the correction of intrarectal intussusception and rectocele. A perineal incision is made. A tunnelling rod 12 having a curved elongate shaft 13 and a generally straight distal end portion 17 terminating in a distal trochar point 16, as exemplified in Fig. 3 a, is inserted into the soft tissue just to the right of the midline and pushed superiorly and laterally to exit at a position on the right lateral inferior aspect of the abdomen through a previously made short incision. The tunnelling rod 12 is pushed until the distal end portion 17 emerges through the short abdominal incision. It is to be noted that a blunt-ended tunnelling rod 12 as exemplified in Fig.

3b, may alternatively be employed in this procedure and indeed may be preferred, since the absence of a sharpened distal tip allows for relatively easy manipulation of the tunnelling rod 12. In this case, a plane may be dissected between the posterior wall of the vagina and the anterior wall of the rectum. The tunnelling rod 12 is carefully passed superiorly and laterally through the dissected soft tissue posterior to the pubic bone, from the perineal incision to an exit point at the position on the right lateral inferior aspect of the abdomen through the previously made short incision. Care is taken when passing the tunnelling rod 12 to avoid bladder injury. The tunnelling rod 12 is pushed until the distal end portion 17 emerges through the short abdominal incision. An olive 11 is then connected to the distal end portion 17 of the tunnelling rod 12, about 25-30mm of which tunnelling rod 12 has been pushed through the short abdominal incision. The frochar point 16 (or domed distal tip 18) is pushed through the hole 27 in the olive 11 from the first side 21 to the second side 22 until the distal trochar point 16 (or domed distal tip 18) is just visible at the second side 22 of the olive 11. The olive 11 is then rotated relative to the tunnelling rod 12 such that the first side 21 and first end 23 of the olive 11 are urged towards the elongate shaft 13 of the tunnelling rod 12 in the direction of the proximal end of the tunnelling rod 12. As the rotational movement is continued, the distal end portion 17 of the tunnelling rod 12 is moved into secure engagement within the longitudinal slot 26 of the olive 11. The trochar point 16 (or domed distal tip 18) at the distal tip of the tunnelling rod 12 is rotated into the longitudinal slot 26 via the second longitudinal opening 29 at the second side 22 of the olive 11, whilst the more proximal part of the distal end portion 17 of the tunnelling rod 12 is pushed into the longitudinal slot 26 via the first longitudinal opening 28 at the first side 21 of the olive 11. The diameter of the more proximal part of distal end portion 17 of the tunnelling rod 12 is slightly larger than the width of the generally straight- sided portion of the longitudinal slot 26 adjacent to the first longitudinal opening 28. The distal end portion 17 of the tunnelling rod 12 must therefore be pushed into the longitudinal slot 26 through the application of force by the user of the instrument. A relatively low force is required, however, since the rotational relationship between olive 11 and tunnelling rod 12 results in the distal end portion 17 being gradually accommodated within the elongate slot 26. Thus, the more proximal part of the distal end portion 17 of the tunnelling rod 12 is rotated into secure engagement within the generally cylindrical bore 30 of the longitudinal slot 26 by the user pushing the first side 21 of the olive 11 towards said more proximal part of the distal end portion 17 of the tunnelling rod 12 such that the more proximal part of the distal end portion 17 is urged through the first longitudinal opening 28 and through the generally straight-sided portion adjacent said first longitudinal opening 28 and defined by opposing walls 33 and 34. As the final, most proximal, part of the distal end portion 17 of the elongate shaft 13

passes through the generally straight-sided portion adjacent the first longitudinal

opening 28 and into secure engagement within the generally cylindrical bore 30, such that the remainder of the elongate shaft 13 extends from the open end 31 of the longitudinal slot 26 at the first end 23 of the olive 11, an audible sound (a "snap") is produced. Thus, the user is given an indication that the distal end portion 17 of the tunnelling rod 12 has been securely engaged within the longitudinal slot 26 of the olive 11. Subsequent passive exit of the distal end portion 17 of the tunnelling rod 12 from the longitudinal slot 26 is resisted as the distal end portion 17 is securely held within the generally cylindrical bore 30. Moreover, the distal end portion 17 is unable to slide out of engagement within the longitudinal slot 26 by longitudinal movement in the direction of the open end 31, since the distal trochar point 16 (or domed distal tip 18) held within the relatively wide part of the longitudinal slot 26 between the hole 17 and the closed end 32 is unable to pass through the relatively narrow part of the longitudinal slot 26 between the hole 27 and the open end 31. The shoulder formed by the proximal surface of the trochar point 16 (or domed distal tip 18) abuts the edge of the hole 27 where it joins the part of the longitudinal slot 26 formed by the cylindrical bore 30 between said hole 27 and the open end 31 of the longitudinal slot 26, thus preventing longitudinal exit of the distal end portion 17 of the tunnelling rod 12 through the open end 31. An implant 40 comprising a generally T-shaped piece of coUagenous material is then attached to the olive 11 by suturing through the implant and the suture hole 36 using, for example, 1.0 Prolene sutures. The implant may comprise a generally T-shaped piece of a coUagenous sheet material disclosed in US 5397535. Once the implant 40 has been sutured to the olive 11, the tunnelling rod 12 is drawn back through the previously created soft tissue tunnel. As the olive 11, connected at the distal end of the tunnelling rod 12, is drawn through the soft tissue tunnel it widens said soft tissue tunnel somewhat, thereby making sufficient space for passage of the implant 40 connected to the olive 11. The tunnelling rod 12 is withdrawn until the implant 40 is positioned at the correct location at the anterior wall of the rectum, where it is sutured in place. The suture between the implant 40 and the olive 11 is then cut and the assembly of tunnelling rod (12) and olive 11 is removed through the perineal incision. At this point, the olive 11 is disconnected from the tunnelling rod 12 by applying sufficient force to rotate the olive 11 relative to the tunnelling rod 12 such that the first side 21 and first end 23 of the olive 11 are moved away from the shaft 13 of the tunnelling rod 12 to release the distal end portion 17 of the shaft 13 from secure engagement within the longitudinal slot 26 in a reversal of the connection procedure hereinbefore described. Once the distal end portion 17 of the elongate shaft 13 has been forcibly released from engagement within the longitudinal slot 26, the olive 11 and tunnelling rod 12 can be separated. The procedure outlined above is then repeated whereby a left hand soft tissue tunnel is created and the tunnelling rod 12 passed therethrough to correctly position a second implant 41 therein, the second implant 41 being sutured in place as before. The implants 40, 41 are then tensioned and sutured in place on the anterior abdomen, more particularly to the periosteum of the pubis. A further implant 42,

being generally rectangular in shape, is sutured in place via tabs at opposite ends thereof in order to correct the rectocele. This further implant 42 adds strength and substance to the support wall between the rectum and the vagina. The surgical instrument 10 according to an aspect of the present invention is not needed for implantation of the further implant 42, although, conveniently, rectocele repair may be effected during the procedure for intussusception repair. The perineal incision is then sutured to complete the procedure. A generally straight shafted tunnelling rod 12 as shown in Figs. 1 and 2 is preferred for use in the surgical correction of full thickness rectal prolapse. In this procedure, the prolapse is everted maximally and a mucosectomy is performed circumferentially using a hand held diathermy device, commencing around l-2cm proximal to the dentate line and continuing over the exposed part of the prolapse and extending for around 3-4cm beyond the apex on its infraluminal surface. Two semi-circumferential incisions measuring approximately 4-5cm are then made with the diathermy device through the denuded muscle of the apex of the prolapse in the right and left antero-lateral quadrants to expose the inner surfaces of the rectal serosa. The tunneling rod 12 is then passed through the right incision in an upward direction passing between the layers of the prolapsed rectal wall, above the external anal sphincter through the pelvic floor and continuing in the subcutaneous layer of the skin, skirting the lateral aspect of the labia/scrotum. The tunneling rod 12 emerges through a previously made short incision overlying the lateral part of the right superior pubic ramus and care must be taken to remain superficial to the adductor longus tendon. Once the end of the tunneling rod 12 has emerged through the incision on the abdominal wall, the tunneling rod 12 should be pushed out far enough to allow the olive 11 to be connected; this is about 25-30mm. The olive 11 is connected to the distal end of the tunneling rod 12 and an implant positioned as hereinbefore described. Once positioned, the implant is sutured to the anterior wall of the rectum to effect repair. Referring to Figs 9-14, an olive holding device 100 comprises a member 101 having a generally central longitudinal channel 102 opening along the entire length of a first side 103 of the member 101. The channel 102 has a first opening 104 at a first end 106 of the member 101 and a second, narrower opening 107 at an inwardly curving tapered second end 108 of the member opposite the first end 106. The channel 102 is generally C-shaped, and is sized and shaped to accommodate an olive 11 as hereinbefore described. The member 101 has first and second outer walls (109 and 111, respectively) either side of the channel 102, the walls 109, 111 being generally parallel to one another and generally perpendicular to the first face 103 of the member 101. A plurality of longitudinal ribs 112 provided on the outer surface of the walls 109, 111 function to improve handling and grip of the device 100. A slot 113 runs longitudinally through the member 101 adjacent to the channel 102, from the first end 106 of the member 101 to a blind end 114 towards the second end 108 of the member 101. The slot 113 divides each of the walls 109, 111 into two parts such that the parts of the walls 109, 111 adjacent to the channel 102 are effectively hinged towards their ends adjacent to the second end 108 of the member 101. At its closed longitudinal

side, i.e. the side opposite the longitudinal opening 104, the channel 102 is partially extended in the form of a secondary, generally U-shaped, channel 120 which runs centrally and longitudinally from the first end 106 of the member 101 to a position 121 towards the second end 108 of the member 101 but not as far towards said second end 108 as said blind end 114 of said slot 113. The olive holding device 100 may be used to facilitate the connection of the olive 11 to the distal end portion 17 of the tunnelling rod 12, as hereinbefore described. In use the olive 11 is slid into the channel 102 through the opening 104 at the first end 106 of the member, such that the first opening 28 of the longitudinal slot 26 of the olive 11 is generally in line with the opening 104 of the channel 102. The second longitudinal opening 29 of the longitudinal slot 26 of the olive 11 is in this arrangement adjacent to the secondary channel 120. The olive 11 may be slid into engagement within the channel 102 in either orientation, i.e. with the first end 23 of the olive 11 moved into proximity with the second end 108 of the member 101 or with the second end 24 of the olive 11 moved into this position. In either orientation, the olive 11 is unable to pass through the relatively narrow opening 107 at the second end 108 of the member 101, and is therefore held within the channel 102. Once the olive 11 is engaged within the channel 102 of the member 101, such that an end 23 or 24 of the olive is adjacent to the opening 107 at the second end 108 of the member 101, the olive 11 may be retained in engagement by the application of force inwardly in the transverse direction to the walls 109, 111, which are movable to grip the olive 11. The olive 11 may then be connected to the tunnelling rod 12 in the manner hereinbefore described. The distal tip (16 or 18) of the tunnelling rod 12 is pushed through the hole 27 in the olive 11, which is accessible via the open channel 102, from the first side of 21 of the olive 11 to the second side 22 of the olive 11 until the distal tip (16 or 18) of the tunnelling rod 12 just emerges at the second side 22 of the olive 11. Conveniently, the tunnelling rod 12 may be pushed until the distal tip (16 or 18) contacts the surface of the secondary channel 120. The assembly of the olive 11 and olive holding device 100 are then rotated relative to the tunnelling rod 12 such that the first side 21 and first end 23 of the olive 11 are urged towards the elongate shaft 13 of the tunnelling rod 12. The distal end portion 17 of the tunnelling rod 12 is moved into secure engagement within the longitudinal slot 26 of the olive 11. The distal tip (16 or 18) of the tunnelling rod 12, 13 is rotated into the longitudinal slot 26 via the second longitudinal opening 29 at the second side 22 of the olive 11, whilst the more proximal part of the distal end portion 17 of the tunnelling rod 12 is pushed into the longitudinal slot 26 via the first longitudinal opening 28 at the first side 21 of the olive 11, the elongate shaft 13 of the tunnelling rod 12 being able to pass through either the first 104 or second 107 opening at an end of the channel 104, depending upon the orientation of the olive 11. Once the olive 11 has been connected to the tunnelling rod 12, the olive 11 is disengaged from the channel 102 of the olive holding device 100 by sliding out of the first opening 104 at the first end 106 of the channel 102. Where the olive 11 is engaged within the channel 102 such that the first end 23 of the olive 11 is adjacent the second end 108 of the member 101, removal of the olive 11 from the member 101 is effected by sliding the member 101 towards the patient until the olive 11 emerges completely from engagement. The procedure may thereafter be

continued as previously described. It is of course to be understood that the invention is not restricted to the above embodiments, details of which are provided by way of example only.

Claims

1. A surgical instrument comprising an olive, the olive being connectable to a tunnelling rod and being adapted for attachment of an implant, wherein the olive is provided with a longitudinal slot therein, at least a portion of which slot opens along its length at a longitudinal opening at a first side of the olive and a first end of which slot opens at a first end of the olive, said slot being operative to securely and releasably engage a distal end portion of the tunnelling rod.

2. A surgical instrument according to claim 1, wherein the depth of the longitudinal slot is at least as great as the diameter of the distal end portion of the tunnelling rod.

3. A surgical instrument according to claim 2, wherein the depth of the longitudinal slot is greater than the diameter of the distal end portion of the tunnelling rod.

4. A surgical instrument according to any one of claims 1 to 3, wherein at least a portion of the longitudinal slot is wider in the transverse direction at or towards its longitudinal closed side than at the longitudinal opening.

5. A surgical instrument according to claim 4, wherein the width in the transverse direction of at least part of the longitudinal slot at or towards the longitudinal opening is less than the diameter of at least part of a first part of the distal end portion of the tunnelling rod and the width in the transverse direction of at least part of the longitudinal slot at or towards the longitudinal closed side is substantially equal to or greater than the diameter of at least part of a second part of the distal end portion of the tunnelling rod more distal than the first part.

6. A surgical instrument according to claim 5, wherein the width in the fransverse direction of the at least part of the longitudinal slot at or towards the longitudinal opening is sufficiently great to allow the at least part of the first part of the distal end portion of the tunnelling rod to pass therethrough upon application of force in the direction of the closed longitudinal side of the slot by hand by a user of the instrument and sufficiently small such that subsequent passive exit of the at least part of the first part of the distal end portion of the tunnelling rod from the slot is resisted.

7. A surgical instrument according to any one of claims 1 to 7, wherein the longitudinal slot is generally straight-sided at or towards the longitudinal opening.

8. A surgical instrument according to any one of claims 4 to 7, wherein the longitudinal slot widens at its longitudinal closed side in the form of a generally cylindrical longitudinal bore.

9. A surgical instrument according to any one of claims 1 to 8, wherein the width in the transverse direction of part of the longitudinal slot towards the first end of the slot is less than the width in the transverse direction of a further part of the slot towards a second, opposite, end of the slot.

10. A surgical instrument according to claim 9, wherein the longitudinal slot widens in the transverse direction in a step between the part of the longitudinal slot towards the first end of the slot and the further part of the slot towards the second end of the slot.

11. A surgical instrument according to any one of claims 1 to 10, wherein the olive is streamlined for travel through a soft tissue tunnel.

12. A surgical instrument according to claim 11, wherein the olive narrows towards the first end thereof in the general direction of either or both of y or z axes of the olive, an x axis thereof being the longitudinal axis, the y axis being the transverse axis and the z axis being perpendicular to both x and y axes.

13. A surgical instrument according to claim 12, wherein the olive additionally narrows towards a second, opposite, end thereof in the general direction of either or both of the y or z axes of the olive.

14. A surgical instrument according to any one of claims 1 to 13, wherein the olive is adapted for attachment of an implant via a suture hole in or through part of the olive.

15. A surgical instrument according to any one of claims 1 to 14, wherein a hole extends through the olive between the first side of the olive and a second side opposite the first side, wherein the longitudinal slot has a first longitudinal opening at the first side of the olive continuous with the hole and extending from said hole to the first end of the olive and a second longitudinal opening at the second side of the olive continuous with the hole and extending from the hole towards a second end of the olive opposite the first end.

16. A surgical instrument according to claim 15, wherein the hole is of greater width in the transverse direction than a part of the longitudinal slot opening at the first longitudinal opening.

17. A surgical instrument according to either of claims 15 or 16, wherein a part of the longitudinal slot opening at the second longitudinal opening is wider in the y (transverse) and/or z direction than a part of the longitudinal slot opening at the first longitudinal opening.

18. A surgical instrument according to any one of claims 1 to 17, wherein the surgical instrument further comprises a tunnelling rod with an elongate shaft.

19. A surgical instrument according to claim 18, wherein the tunnelling rod comprises a borer.

20. A surgical instrument according to either of claims 18 or 19, wherein the elongate shaft is generally cylindrical with a diameter of between 4 and 8mm.

21. A surgical instrument according to any one of claims 18 to 20, wherein the elongate shaft is generally straight.

22. A surgical instrument according to any one of claims 18 to 20, wherein the elongate shaft is at least partially curved.

23. A surgical instrument according to any one of claims 18 to 22, wherein the tunnelling rod is provided with a sharpened distal tip.

24. A surgical instrument according to claim 23, wherein the sharpened distal tip comprises a trochar point.

25. A surgical instrument according to claim 24, wherein the trochar point is fixed.

26. A surgical instrument according to claim 25, wherein the trochar point is formed integrally with the distal end portion of the tunnelling rod.

27. A surgical instrument according to any one of claims 18 to 22, wherein the tunnelling rod is provided with a blunt distal tip.

28. A surgical instrument according to claim 27, wherein the distal tip is domed.

29. A surgical instrument according to any one of claims 18 to 28, wherein the olive comprises an olive according to any one of claims 9, 10 and 17 and the distal end portion of the tunnelling rod is of greater diameter at or towards the distal tip thereof than at a more proximal part of the distal end portion.

30. A surgical instrument according to claim 29, wherein the distal end portion of the tunnelling rod widens in a step between the more proximal part of the distal end portion and the distal tip.

31. A surgical instrument according to any one of claims 1 to 30, wherein the olive is connectable to the tunnelling rod in such a way as to produce an audible sound.

32. A surgical instrument according to any one of claims 1 to 31, wherein the olive is connectable to the tunnelling rod via an interference fit.

33. A surgical instrument according to any one of claims 1 to 32, wherein the surgical instrument further comprises an olive holding device.

34. A surgical instrument according to claim 33, wherein the olive holding device comprises a member having a longitudinal channel opening at a first side of the member and at a first end of the member , the channel being configured to accommodate the olive such that the longitudinal opening of the longitudinal slot of the olive remains accessible.

35. A surgical instrument according to claim 34, wherein the longitudinal channel of the member has a first opening at the first end of the member and a second, narrower, opening at a second end of the member opposite the first end, the olive being passable through said first opening but not through said second opening.

36. A surgical instrument according to either of claims 34 or 35, wherein the member has movable opposing walls either side of the longitudinal channel movable to effect gripping of the olive when accommodated within the channel.

37. A surgical kit comprising a surgical instrument according to any one of claims 1 to 36 and an implant.

38. A surgical kit according to claim 37, wherein the implant comprises a coUagenous material.

39. A surgical kit according to either of claims 37 or 38, wherein the implant is generally "T"-shaped.

40. A surgical kit according to any one of claims 37 to 39, wherein the kit further comprises an implant for rectocele repair.

1. A surgical kit according to claim 40, wherein the implant for rectocele repair comprises a generally rectangular implant with tabs at opposite ends.