GB2448123A

GB2448123A - Kirschner wire bending tool.

Info

Publication number: GB2448123A
Application number: GB0614147A
Authority: GB
Inventors: Paul James Mackenney
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-07-17
Filing date: 2006-07-17
Publication date: 2008-10-08
Anticipated expiration: 2026-07-17
Also published as: GB0614147D0; GB2448123B

Abstract

A tool for bending lengths of surgical (Kirschner) wire to form osteotomy fixation units or staples. The tool comprises a slide member 1 axially slidably recievable in a sleeve member (fig 5). The slide has a raised section 2 which is tapered at either end 2di, 2dii and has a number of transverse slots 2a, 2b, 2c for receiving the wire to be bent. The sleeve member has a channel (3, fig 5) which is shaped to cooperate with the slide member. The wire to be bent is placed in one of the transverse slots of the slide member and the slide member is subsequently pushed into the channel of the sleeve member. The device allows wires to be bent at a number of different angles. Also claimed is a crimping device (fig, 14) comprising a pair of pliers with jaws for creating a crimp in a section of wire held between said jaws.

Description

1 2448123 SURGICAL TOOL & CRIMPER FOR OSTEOTOMY FIXATION UNIT

MANUFACTURE.

FIELD OF THE INVENTION.

The invention relates to a Surgical Tool and a Crimper for the on-table' manufacture of sterile K-wire osteotomy fixation units.

BACKGROUND.

Staples for the fixation of osteotomies and the compression ofjoints to obtain bony fusion are well-recognised medical devices. There are a number of problems with using ready-made staples in the operating theatre: 1. Staples are made to certain sizes and shapes. Therefore to have the exact staple size and shape needed for each operation, an enormous number of different sizes and shapes of staple must be kept in stock in the Operating Theatre.

2. Staples are not always supplied in sterile packaging. Therefore a Pack containing a set of staples of varying sizes and shapes has to be sterilised for each operation. l'his Pack of staples has to be re-stocked and re-sterilised after each operation to make sure the full range is available at each subsequent operation.

3. Staples are expensive, particularly the staples that apply compression across the osteotomy/flision site. In addition, some staples require refrigerated storage (memory staples).

THE INVENTION

The invention provides firstly a surgical tool as defined in claim 1, and secondly a combination of surgical tool and crimping device as defined in claim 7. The invention comprises two components: a Surgical Tool with slide member and sleeve parts that bends the K-wire into an osteotomy fixation unit (resembling a staple); a Crimper that places a variable bend in the cross-bar of the osteotomy fixation unit. These components are preferably manufactured in medical grade stainless steel 316 to allow them to be sterilised and used in the Operating Theatre. The invention seeks to solve the problems outlined above (see BACKGROUND) by enabling the manufacture from sterile K-wire of fixation units to almost any specification during the operation (on-table'): 1. The fixation unit is made from a length of sterile K-wire using the sterilised Surgical Tool: the limbs of the fixation unit (those parts of the unit that are inserted into the bone) are cut to the required length by the surgeon. The sterile Crimper puts an infinitely variable bend in the cross-bar of the fixation unit: the width of the K-wire fixation unit is thus also determined by the surgeon. The Former and Crimper thus can supply a wide range of fixation unit sizes from a length of K-wire.

2. Lengths of K-wire are supplied sterilised, and the Surgical Tool and Crimper can be included in Standard Sterile Instrument Packs. Thus the need for a separate Sterile Pack of a set of staples is obviated, and the time spent re-stocking and sterilising this Pack avoided.

3. The Crimper can be used to apply compression at the osteotomy or fusion site, by application of a crimp or bend in the fixation unit cross-bar after almost complete insertion of the fixation unit into the bone.

DRAWThEGS.

The component parts of the Surgical Tool and Crimper are illustrated in drawings, which

accompany the following descriptions:

Figure 1: The slide member of the Surgical Tool in Plan View showing: the flat section; the raised section with slots and tapers.

Figure 2: The slide member of the Surgical Tool in Side View showing: the flat section; the raised section with slots and tapers.

Figure 3: The slide member of the Surgical Tool in End View showing: the flat section; the raised section with slot and taper at relevant end.

Figure 4: A photograph of a prototype slide member.

Figure 5: The sleeve of the Surgical Tool in Plan View showing the bottom plate wide and narrow sections and groove for the K-wire (top plate absent).

Figure 6: The sleeve of the Surgical Tool in End View showing the bottom plate wide and narrow sections and groove for the K-wire, and the top plate.

Figure 7: The sleeve of the Surgical Tool in Side View showing the bottom plate wide and narrow sections and groove for the K-wire, and the top plate.

Figure 8: A photograph of a prototype sleeve bottom plate.

Figure 9: The Crimper Holding Limb in Side View.

Figure 10: The Crimper Holding Limb in Plan View.

Figure 11: The Crimper Holding Limb in End View.

Figure 12: The Crimper Crimping Limb in Side View.

Figure 13: The Crimper Crimping Limb in Plan View Figure 14: The assembled Crimper.

THE SURGICAL TOOL.

The Surgical Tool comprises a Slide member and a Sleeve, the first sliding into the second to bend the K-wire.

The Slide Member.

The Slide Member is illustrated in Figures Ito 4, and has the following features: 1. A flat section (1) that fits into the Sleeve and ensures that the Slide Member slides accurately within the Sleeve.

2. A raised section (2) that has transverse slots (2a, 2b and 2c), which hold the wire during the bending process. The raised section has tapers (2di and 2dii) at either end that enables over-bending of the K-wire. Over-bending is explained in the Section entitled: OPERATION OF THE SURGICAL TOOL'.

The Sleeve.

The Sleeve is illustrated in Figures 5 to 7, and has the following features: 1. A bottom plate (3) that has been machined to accept both the flat and raised sections of the Slide Member. Accordingly there are two sections of the bottom plate: a. A wide section (3e) that accepts the flat section of the Slide Member.

b. A narrow section (31) that accepts the raised section of the Slide Member. The narrow section has a groove (3g) machined into it. This groove contains the bending K-wire as the Slide Member (holding the K-wire) is slid into the Sleeve. To reduce the forces required to bend the K-wire, the groove has a near wide fluted part (3gi) and a far narrow part (3gii) with a size comparable to the diameter of the wire. The narrow section has a taper (3h) at the far end that corresponds to the taper of the Slide Member: this permits-over-bending of the K-wire. Over-bending is explained in the Section entitled: OPERATION OF THE SURGICAL TOOL'.

2. A top plate (4) that bolts to the machined bottom plate (3), to convert the open-plan bottom plate into the enclosed channel that will accept the Slide Member. The length of the channel is the same as the length of the Slide Member.

THE CRIMPER.

The Crimper is akin to a pair of pliers. The jaws of the pliers have been modified so that one of the jaws holds the cross-bar of the K-wire fixation unit, and the other applies the crimp.

The Holding Limb.

The Holding Limb (5) is expanded at the Jaw (Sj) to contain a slot 5(k). The slot holds the cross-bar of the fixation unit and the top few millimetres of the limbs of the fixation unit. The Jaw can be used to hold the fixation unit for both crimping the cross-bar and insertion of the fixation unit into bone. The jaw is divided into two halves by another slot (51). This slot permits passage of the mandrel of the Crimping Limb (6) and thus the application of the crimp into the cross-bar of the fixation unit. There is hole (5m) across the Holding Limb that contains the spindle (7), which acts as the fulcrum for the application of force. The Holding Limb also has an arm (Sn) that allows the application of manual force across the two jaws (similar to pliers).

The Crimping Limb.

The Crimping Limb (6) has a mandrel (6o), a hole (6p) for the passage of the spindle (7) that acts as the fulcrum for the application of force, and an arm (6q) for the application of manual force. The mandrel engages with that segment of the cross-bar of the fixation unit which lies in the slot (51) of the Holding Jaw, and can be used to crimp the cross-bar.

The Spindle.

The spindle acts as the fulcrum or centre of rotation of the Crimper, allowing the generation of force between the two jaws when squeezing the arms together. It is a cylinder that fits through holes (Sm) and (6p) in the Holding and Crimping Limbs respectively.

OPERATION OF THE SURGICAL TOOL.

Depending upOn the type of fixation unit required (90 or 65/115 ), different slots in the Slide Member are employed.

Manufacture of 90 K-Wire Fixation Unit.

This method produces a fixation unit where the angle between the limb and cross-bar is 90 on both sides. This fixation unit is used when the surface of the bone is perpendicular to the direction of insertion of the fixation unit. The length of K-wire is placed in the slot (2a), with approximately equal lengths of wire either side of the slot. The Slide Member is then introduced into the Sleeve, and pushed in fully. The Slide Member is then withdrawn. The K-wire, because of the shape of the channel (3g), has been bent at the ends of the slot (2a).

However, the angle of these bends is less than 90 because of the elastic nature of the K-wire, which springs back upon withdrawal from the Sleeve. The K-wire is therefore removed from the slot (2a), rotated, and replaced in the slot (2a) such that the limbs of the K-wire fixation unit are now pointing towards the taper (2di). The Slide Member is then re-introduced into the Sleeve, with the limbs of the K-wire fixation unit going first. The Slide Member is pushed into the Sleeve fully. Because of the Taper (2di) and the corresponding Sleeve taper (3h), the limbs of the K-wire fixation unit are overbent'. Upon removal of the Slide Member, the limbs of the K-wire fixation unit spring back (due to the elastic nature of the K-wire), such that the angle between limb and cross-bar is 90 . Manufacture of the K-wire fixation is thus complete.

Manufacture of the 65/115 K-wire Fixation Unit.

This method produces a fixation unit where the angle between the limbs and cross-bar are asymmetrical: 65 on one side and 115 on the other. This fixation unit is used when the surface of the bone is somewhat oblique to the direction of insertion of the fixation unit. The length of K-wire is placed in the slot (2b), with approximately equal lengths of wire either side of the slot. The Slide Member is then introduced into the Sleeve, and pushed in fully.

The Slide Member is then withdrawn. The K-wire, because of the shape of the channel (3g), has been bent at the ends of the slot (2b). However, the angle of these bends is less than the required 65 and 115 because of the elastic nature of the K-wire, which springs back upon withdrawal from the Sleeve. The K-wire is therefore removed from the slot (2b), rotated, and replaced in the slot (2c) such that the limbs of the K-wire fixation unit are now pointing towards the taper (2dii). The Slide Member is then re-introduced into the Sleeve, with the limbs of the K- wire fixation unit going first. The Slide Member is pushed into the Sleeve fully. Because of the Taper (2di) and the corresponding Sleeve taper (3h), the limbs of the K-wire fixation unit are overbent'. Upon removal of the Slide Member, the limbs of the K-wire fixation unit spring back (due to the elastic nature of the K-wire), such that the angles between limbs and cross-bar are the required 65 and 115 . Manufacture of the K-wire fixation is thus complete.

OPERATION OF THE CRIMPER.

The manufactured 90 fixation unit is inserted into slot (5k). By the application of manual pressure to the arms (5n) and (6q) of the Crimper, force is applied to the cross-bar of the fixation unit by the hook (6o) of the Crimping Limb in the slot (51) of the Holding Jaw. The size of the crimp in the cross-bar of the fixation unit depends upon the amount of force applied to the arms.

Claims

CLAIMS.

1. A surgical tool for bending a length of Kirschner wire (K-Wire) into the shape of a bone fixation staple under sterile conditions, comprising: a slide member axially slidably receivable in an enclosed channel in a sleeve, the slide member comprising a first transverse slot for receiving a central portion of the cut length of K-Wire, wherein a portion of the slide member forwardly of the first transverse slot is formed with tapered sides, tapering together in the forward direction, a portion of the slide member rearwardly of the first transverse slot is formed with parallel sides; a first mouth portion of the enclosed channel is outwardly flared to engage and bend together end portions of the K-Wire projecting from the elongate slot as the slide member is moved axially into the channel; a second portion of the enclosed channel immediately deeper than the flared mouth is formed with parallel sides and; a third portion of the enclosed channel deeper than the portion with parallel sides is formed with tapered sides, tapering together as the channel gets deeper; whereby when a straight cut length of K-Wire is placed in the first transverse slot with its end portions protruding from opposite ends of the slot, and the slide member is pushed firmly into the channel in the sleeve with its tapering end portion leading, the wire is bent by the first and second portions of the channel to a preform condition in which the protruding end portions are bent through 900 while the slide member is in the channel in the sleeve but relax to less than 9 0 on removal of the slide member from the sleeve; and when the same cut length of K-Wire in its preform condition is inserted into the first transverse slot with its bent-over end portions pointing forwardly, and the slide member is pushed firmly into the channel in the sleeve with its tapering end portion leading, the wire is bent by the first and third portions of the channel to a fmal shape in which the protruding ends of the wire are over-bent to more than 90 while the slide member is in the sleeve but relax to substantially 900 on removal of the slide member from the sleeve.

2. A surgical tool according to claim 1, wherein the first transverse slot extends perpendicularly to the sliding direction of the slide member.

3. A surgical tool according to either preceding claim, wherein the slide member has formed therein a second transverse slot across the portion of the slide member with parallel sides, the slot angle being substantially 85 to the sliding direction; and a third transverse slot parallel to the second through the tapered forward end portion or through a second tapered end portion, whereby when a straight cut length of KWire is placed in the second transverse slot with its end portions protruding from opposite ends of the slot, and the slide member is pushed firmly into the channel in the sleeve, the wire is bent by the first and third portions of the channel to a preform condition in which the protruding end portions are bent through 65 and 115 respectively while the slide member is in the channel in the sleeve hut relax to less than 65 /l 15 on removal of the slide member from the sleeve; and when the same cut length of K-Wire in its preform condition is inserted into the third slot with its bent-over end portions pointing forwardly, and the slide member is pushed fully into the channel in the sleeve with the third slot leading, the wire is bent by the first and third portions of the channel to a final shape in which the protruding ends of the wire are over-bent to more than 65 and 1150 respectively while the slide member is in the sleeve but relax to substantially 65 /i 15 on removal of the slide member from the sleeve.

4. A surgical tool according to claim 3, wherein the slide member has two identical tapered end portions one at each end of the parallel sided portion, and the first slot is between the parallel sided portion and a first of the tapered end portions; and the second and third slots are through the parallel sided portion and a second of the tapered end portions at the opposite end of the parallel sided portion, which becomes the leading end portion when the slide member is turned through 180 .

5. A surgical tool according to any preceding claim, wherein the slide member and sleeve are both made from surgical grade stainless steel.

6. A surgical tool according to claim 5, wherein the steel is stainless steel 316.

7. Surgical apparatus according to claim 6, wherein one of the jaws of the crimping tool compris a generally cylindrical mandrel around which the K-Wire of the central portion can be bent and the other of the jaws comprises a channel into which the mandrel can pass when the jaws of the crimping tool are closed together.

S.

I

I S. IS

7. A surgical tool according to any preceding claim, in combination with a crimping tool which comprises a pair of pliers with jaws which overlap to create a crimp in a length of K-Wire gripped and bent between the jaws.

8. A surgical tool combination according to claim 7, wherein one of the jaws of the crimping tool comprises a generally cylindrical mandrel around which a portion of the K. Wire can be bent and the other of the jaws comprises a channel into which the mandrel can pass when the jaws of the crimping tool are closed together.

Amendments to the claims have been filed as follows CLAIMS.

1. Surgical apparatus comprising a tool for bending a straight cut length of Kirscbner wire (K-Wire) under sterile conditions into the shape of a bone fixation staple which COuipnscS a central portion and two substantially paraliel prong portions, wherein the tool comprises: a slide member axially slidably receivable in an enclosed channel in a sleeve, the slide member comprising a first transverse slot extending perpendicularly across the slide member for receiving a central portion of the cut length of K-Wire with the end portions of the cut length of K-Wire protruding from opposite ends of the transverse slot, wherein: a portion of the slide member forwardly of the first transverse slot is formed with tapered sides, tapering together in the forward direction, a portion of the slide member rearwardly of the first transverse slot is formed with parallel sides; a first mouth portion of the enclosed channel is outwardly flared to engage *::* and bend together the end portions of the K-Wire projecting from the elongate slot as the slide member is moved axially into the channel; a second portion of the enclosed channel immediately deeper than the flared mouth is formed with parallel sides and; a third portion of the enclosed channel deeper than the portion with parallel sides is formed with tapered sides, tapering together as the channel gets * S.

deeper; whereby when a straight cut length of K-Wire is placed in the first transverse slot with its end portions protruding from opposite ends of the slot, and the slide member is pushed firmly into the channel in the sleeve with its tapering end portion leading the wire is bent by the first and second portions of the channel to a preform condition in which the protruding end portions are bent through 900 while the slide member is in the channel in the sleeve but relax to less than 90 on removal of the slide member from the sleeve; and when the same cut length of K-Wire in its preform condition is turned around and inserted into the first transverse slot with its bent-over end portions pointing forwardly, and the slide member is pushed firmly into the channel in the sleeve with its tapering end DO lion le ding, the wire is bent by the first and thirdportions of the channeltoafinal shape in which the protruding ends of the wire are over-bent to more than 900 while the slide member is in the sleeve but relax to substantially 90 on removal of the slide member from the sleeve.

2. Surgical apparatus comprising a tool according to claim 1, wherein the slide member has formed therein a second transverse slot across the portion of the slide member with parallel sides, the slot angle being substantially 85 to the sliding direction; and a third transverse slot parallel to the second through the tapered forward end portion or through a second tapered end portion, whereby when a straight cut length of K-Wire is placed in the second transverse slot with its end portions protruding from opposite ends of the slot, and the slide member is pushed firmly into the channel in the sleeve, the wire is bent bythe first and third portions of the channel to a preform condition in which the protruding end portions are bent through 65 and 1150 respectively while the slide member is in the channel in the * *..

sleeve but relax to less than 65 /i 15 on removal of the slide member from the sleeve; when the same cut length of K-Wire in its preform condition is turned around and ** * inserted into the third transverse slot with its bent-over end portions pointing forwardly, and the slide member is pushed fully into the channel in the sleeve with the third slot leading, the wire is bent by the first and third portions of the channJ to a final shape in which the protruding ends of the wire are over-bent to more than 65 and 1150 respectively while the slide member is in the sleeve but relax to substantially 65 /i 15 on removal of the slide member from the sleeve.

3. Surgical apparatus comprising a tool according to claim 2, wherein the slide member has two identical tapered end portions one at each end of the parallel sided portion, and the first slot is between the parallel sided portion and a first of the tapered end portions; and the second and third slots are through the parallel sided portion and a second of the tapered end portions at the opposite end of the parallel sided portion, which becomes the leading end portion when the slide member is turned through 1800.

4. Surgical apparatus comprising a tool according to any preceding claim, wherein the slide member and sleeve are both made from surgical grade stainless steel.

5. Surgical apparatus comprising a tool according to claim 4, wherein the steel is stainless steel 316.

6. Surgical apparatus comprising a tool according to any preceding claim, in combination with a crimping tool which comprises a pair of pliers with jaws which overlap to create a crimp in the central portion of a bone fixation staple made from a length of K-Wire using a tool according to any preeding claim when that central portion of the bone fixation staple is gripped and bent between the jaws.