WO2010026398A2

WO2010026398A2 - Targeting apparatus

Info

Publication number: WO2010026398A2
Application number: PCT/GB2009/002149
Authority: WO
Inventors: Christopher John Sloss; Ryan Taylor
Original assignee: Comis Orthopaedics Ltd
Current assignee: Comis Orthopaedics Ltd
Priority date: 2008-09-06
Filing date: 2009-09-07
Publication date: 2010-03-11
Anticipated expiration: 2011-03-06
Also published as: GB0816324D0; GB201003308D0; GB2473305A

Description

Targeting Apparatus

This invention relates to targeting apparatus. More particularly, but not exclusively, this invention relates to targeting apparatus for use in targeting apertures in work pieces, such as nails embedded in articles to allow drilling through the articles into the apertures

During certain procedures, it is often necessary to insert a nail into an article, and then to drill laterally through the article to insert fasteners, such as screws, bolts or the like into apertures at the embedded end region of the nail. There can be difficulties in ensuring that the screws or bolts are aligned with the apertures in the nail.

According to one aspect of this invention, there is provided a targeting apparatus for targeting a preselected region of a work piece, the apparatus comprising a locating device for locating the position and orientation of the work piece, a position determining guide mountable on the work piece, wherein the locating device is co- operable with the position determining guide to determine the position and orientation of the work piece, and thereby determine the position and orientation of the aforesaid preselected region of the work piece.

According to another aspect of this invention, there is provided a method of targeting a preselected region of a work piece, the method comprising arranging a position determining guide on the work piece and moving a locating device to co-operate with the position determining guide to determine the position and orientation of the work piece, and thereby determine the position and orientation of the aforesaid preselected region of the work piece.

According to another aspect of this invention, there is provided the use of a locating device in a targeting apparatus to locate the position and orientation of a work piece, wherein the targeting apparatus comprises a position determining guide mountable on the work piece, wherein the locating device is co-operable with the position determining guide to determine the position and orientation of the work piece, and thereby determine the position and orientation of the aforesaid preselected region of the work piece.

The locating device may comprise a locating member having a locating end portion engageable with the position determining guide. The locating member may comprise a stylus or probe.

The step of moving the locating device may comprise moving the locating member so that the locating member engages the position determining guide. Desirably, the step of moving the locating device comprises moving the locating member so that the locating end portion engages the position determining guide.

The locating device may comprise an arm having a plurality of arm sections. Each arm section may be connected to at least one further arm section by a respective joint.

The locating member may be provided at an end of the arm. Conveniently, the locating member is provided at an end section of the arm.

In a first embodiment, the locating device may comprise a co-ordinate measuring machine.

Each joint may allow pivoting movement of connected arm sections relative to each other. Each joint may allow movement of the respective arm sections relative to each other in three dimensions. In a second embodiment, the arm may include a drive assembly to move the arm sections. Desirably, the drive assembly comprises a respective drive arrangement associated with each joint to move the arm sections connected to each other at the respective joint.

The arm sections may be movably connected to one another so that the respective drive arrangements can move the arm sections. The arm sections may be connected to one another to be movable relative to each other in two dimensions. Conveniently, the arm sections are pivotally connected to each other,

In the second embodiment, the locating device may comprise a robot arm. A suitable such robot arm is sold by the company S T Robotics.

The locating device may comprise at least two arm sections. Desirably, the locating device comprises four arm sections.

The locating device may comprise a base having a securing arrangement to secure the base to a support. Desirably, the base can be secured to the support in a fixed position relative to the work piece.

The securing arrangement may comprise a clamp to clamp the locating device to the support.

The arm may be movably mounted on the base. Desirably, the arm is pivotally mounted on the base.

In the first embodiment, the locating device may comprise a connector to connect the arm to the base. The connector may comprise a sleeve to receive the arm therein. The sleeve may be configured to allow rotation of the arm.

In the second embodiment, the base may house a drive arrangement to drive the arm. Desirably, the drive arrangement housed in the base is configured to drive the arm pivotally about the base.

The position determining guide may comprise a datum indicator. The position determining guide may comprise a mounting portion to mount the position determining guide on the work piece.

The work piece may include a mounting formation on which the position determining guide can be mounted.

The position determining guide may comprise a fastener to fasten the mounting portion to the mounting formation. The fastener may comprise a bolt.

The mounting portion may be configured to co-operate with the mounting formation on the work piece and thereby hold the position determining guide to the work piece at said mounting formation

The position determining guide may comprise at least one guide means. Conveniently, the position determining guide comprises a plurality of guide means, whereby the locating device may co-operate with the guide means to determine the position and orientation of the work piece.

The, or each, guide means may be provided on the mounting portion. The position determining guide may comprise first, second and third guide means. In a first embodiment, the guide means comprise elongate members., At least one of the elongate members may be perpendicular to the others. Desirably, the locating member may co-operate with the guide means to determine the position and orientation of the work piece. In one embodiment, the locating end portion of the locating member may co-operate with the guide means by engaging the guide means

In a first embodiment, the, or each, guide means may comprise a guide portion, which may comprise a projecting member.

In a second embodiment, the, or each, guide means may comprise a sensor, such as a touch sensor, to sense the locating member. In this embodiment, the position determining guide may comprise a carrier for the, or each, guide means.

In the second embodiment, the carrier may comprise an operating device for operating the, or each, guide means. The operating device may comprise a circuit board. The carrier may be attached to the mounting portion.

The step of moving the locating device may comprise moving the locating member so that the locating member engages the, or at least one.guide means.

The locating device may include a holder to hold the locating member. The holder may be mounted on the arm. The holder may be mounted on the arm for movement in three dimensions.

Conveniently, the holder is mounted on one of the arm sections of the arm.

The targeting apparatus may further include a tool guide to guide a tool towards said preselected region of the work piece. The tool guide may be mountable on the holder. The tool guide may be mountable on the holder a predetermined distance from said locating member.

Desirably, the tool guide is removably mounted on the holder. The tool guide may comprise a tube to receive a tool therethrough.

The holder may comprise a main portion. The main portion may define an aperture through which the tool guide can extend.

First co-operating formations may be provided on the main portion to co-operate with second co-operating formations on the tool guide and secure the tool guide to the main portion. The first and second co-operating formations may comprise cooperating bayonet fastenings.

The targeting apparatus may comprise a data processing arrangement. The data processing arrangement may comprise a controller to control movement of the locating device. The controller may be connected to the drive assembly to control movement of the arm sections.

The data processing arrangement may be configured to process data relating to the position and orientation of the position determining guide. The data processing arrangement may comprise a computer.

The data processing arrangement may include information relating to the work piece, and said information may include dimensions of the work piece. The data processing arrangement may be provided with information relating to the position and orientation of the preselected region relative to the mounting formation on the work piece. The data processing arrangement may include information relating to the position and orientation of the mounting portion on the position determining guide. The method may comprise inputting to the data processing arrangement said information relating to the position and orientation of the mounting portion on the position determining guide.

The method may comprise recording the position of the locating member at engagements of the locating member with the position determining guide. The step of recording the positions may comprise recording the positions on the data processing arrangement.

Thus, in one embodiment, when the position determining guide is mounted on the work piece, the co-operation of the locating member with the position determining guide provides information to the data processing arrangement to allow the data processing arrangement to determine the position and orientation of the work piece, and of the aforesaid preselected region, relative to the location device. This information allows the data processing arrangement to guide the tool guide to the location of the aforesaid preselected region.

The targeting apparatus may include a display arrangement to display the movement of the locating device. When the information relating to the work piece and the position determining device is entered onto the data processing arrangement, the display arrangement may display the work piece.

The display arrangement may display the movement of the locating device relative to the work piece, thereby allowing the user to determine when the tool guide is aligned with the preselected region of the work piece.

The display arrangement may comprise a computer monitor, or any other suitable display arrangement comprising a screen, and operable by a computer. The work piece may be embedded in an article, and the method may comprise inserting a tool into the tool guide, and moving the holder until the display arrangement indicates that the tool is aligned with the aforesaid preselected region.

The method may comprise moving the arm so that the locating member engages the position determining guide, and recording on the data processing arrangement the position of the locating member in engagement with the position determining guide, thereby allowing the data processing arrangement to determine the position and orientation of the work piece.

The method may include arranging for the position and orientation of the work piece, and of the position of the tool guide, to be displayed by the display arrangement.

The method may further include moving the arm until the tool guide is aligned with the preselected region of the work piece.

The step of moving the arm may comprise observing the display arrangement to allow the user guide the arm until the tool guide is aligned with the preselected region of the work piece. Alternatively, the step of moving the arm and/or moving the holder may comprise allowing the operating device to effect movement of the arm and/or the holder until the tool guide is aligned with the preselected region of the work piece.

The method may include using said tool during removal of material from said article to provide access to the aforesaid preselected region of the work piece. The tool may comprise drill guide into which a drill bit can be inserted to drill the article. Where the work piece is embedded in an article of a second material that is surrounded or embedded in a first material that is softer than the second material, the method may comprise inserting a first tool into the tool guide.

When said display arrangement indicates that the tool guide is aligned with the aforesaid preselected region, the method may comprise removing the first material with the first tool, and then inserting a second tool into the tool guide and removing the second material using the second tool to provide access to the work piece.

The first tool may comprise a bladed tool to cut through the first material. The second tool may comprise a drill guide for a drill bit to drill through the second material.

In the second embodiment, after the position and orientation has been determined by the data processing arrangement, the method may comprise operating the control means to actuate the drive assembly and move the locating member to the preselected position. The method may comprise allowing the drive assembly to move the locating member until the tool guide is aligned with the preselected region of the work piece.

The tool guide can then be used to guide tools to the article and remove material from the article to allow access to the work piece.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a first embodiment of a targeting apparatus;

Figure 2 is a view along the lines Il - Il in Figure 1 showing a first tool; Figure 3 is a view along the lines Il - Il in Figure 1 showing a second tool;

Figure 4 is a side view of a position determining guide for use in the targeting apparatus shown in Figurei ;

Figure 5 is a perspective view of the position determining guide shown in Figure 4;

Figure 6 is a close up of a clamp for use in the targeting apparatus shown in Figure 1 ;

Figure 7 is a diagrammatic side view of a first embodiment of a targeting apparatus incorporating a data processing arrangement and a display arrangement;

Figure 8 is a perspective view of a second embodiment of a targeting apparatus;

Figure 9 is a perspective view of a work piece having mounted thereon a position determining guide for use with the second embodiment;

Figure 10 is a perspective view of the work piece shown in Figure 9;

Figure 11 is a perspective view of the position determining guide shown in Figure 9; and

Figure 12 shows a fastener for fastening the mounting portion to the work piece.

Figure 1 shows a first embodiment of a targeting apparatus 10 for targeting a first region 12 of a work piece. In the embodiment described herein, the work piece is a nail 14. The first region 12 of the nail 14 is a first aperture 16 through the nail 14. The purpose of targeting the aperture 16 is to enable a screw to be inserted therethrough.

The nail 14 is embedded in an article 20 (shown in broken lines) and, therefore, the aperture 16 is not visible to the person using targeting apparatus 10. The article 20 may have an inner region of a relatively hard material surrounding the nail 14, and an outer region of a relatively soft material surrounding the inner region.

As can be seen, the nail 14 has a second region 22, which is a second aperture 24. It may be desired for the targeting apparatus to target the second aperture 24 as well as, or instead of, the first aperture 16.

The following description relates to the targeting of the first aperture 16, but it will be appreciated that the description could equally relate to the targeting of the second aperture 24.

The targeting apparatus 10 comprises a locating device, which, in the embodiment shown, is in the form of a co-ordinate measuring machine 26.

Co-ordinate measuring machines are well known, and suitable such machines are sold by the company Hexagon Metrology. US patent No. 6, 931 , 745 discloses an example of a suitable co-ordinate measuring machine.

The co-ordinate measuring machine 26 comprises an arm 28 mounted on a base 30. The base 30 comprises a securing arrangement in the form of a clamp 32 to secure the arm 28 to a support 34, such as a table (shown in broken lines in Figure 7). The clamp 32 comprises first and second opposed clamping members 36, 38 to engage the support 34, and a locking screw 39 to lock the first and/or the second clamping members 36, 38 in position. An angle adjustment screw 40 is also provided to adjust the angle of the base 30 relative to the support 34.

The base 30 further includes a pair of holding members 42 spaced from each other one above the other. Each holding member defines a hole to receive and hold a sleeve 44.

The sleeve 44 defines a cylindrical recess to receive a portion of the arm 28, as described below. The holding members 42 are attached to a mounting plate 46 upon which the clamping members 36, 38 are mounted.

Referring back to Figure 1 , the arm 28 comprises first, second and third arm sections 28A, 28B, and 28C, which are connected to each other by first and second joints 29A and 29B. Each joint 29A and 29B allows rotational movement of the arm sections connected thereto about mutually perpendicular axes X and Y.

The first arm section 28A is mounted on the base 30, by being received in the sleeve 44. The first arm section 28A is rotatable about its main axis Z in the sleeve 44.

A holder 48 is connected to the free end of the third arm section 28C by a third joint 49, which allows rotational movement of the holder 48 relative to the third arm section 28C about two mutually perpendicular axes A and B.

Thus, the arm sections 28A, 28B and 28C can be manipulated to move the holder 48 to any position within reach of the arm 28. The holder 48 is provided with a handle 47 to facilitate manipulation of the holder 48 by a user. Referring to Figure 7, the co-ordinate measuring machine 26 comprises a data processing arrangement in the form of a computer 50. The computer 50 includes a display arrangement in the form of a computer monitor or screen 52.

The computer 50 is electronically connected to each of the joints 29A, 29B and 48, so that the movement of the arm sections 28A, 28B and 28C, and of the holder 48, can be determined and measured by the computer 50. The movement of the holder 48 can be displayed on the screen 52.

A locating member 54, in the form of a probe, is provided on the holder 48 and comprises an elongate main portion 56 and a generally spherical locating end portion 58.

The dimensions of the locating member 54 and the position of the locating end portion 58 relative to the holder 48 are programmed into the computer 50. Thus, by measuring the movement and/or the positions of the arm sections 28A, 28B and 28C, and of the holder 48, the computer 50 can determine precisely the position and movement of the locating end portion 58 of the locating member 50.

The targeting apparatus 10 further includes a position determining guide 60 (shown in more detail in Figures 4 and 5), which comprises a mounting portion 62. The nail 14 includes a mounting formation 64, which can co-operate with the mounting portion 62 to mount the position determining guide 60 on the nail 14.

A fastener in the form of a bolt 65 is provided to fasten the position determining guide 60 on the mounting formation 64.

In addition, the nail 14 includes an elongate main part 68 in which the first and second apertures 16, 24 are defined. The nail 14 also includes a head part 70 on the main part 68; the mounting formation 64 is provided on the head part 70. The dimensions of the nail 14, including the positions of the first and second apertures 16, 24 in the main part 68 relative to the mounting portion 62 are programmed into the computer 50.

The position determining guide 60 further includes three guide means in the form of guide portions. In the embodiment shown in Figures 4 and 5, each guide portion comprises a projecting member 66 on the mounting portion 62.

The dimensions of the position determining guide 60, including the lengths and positions of the three projecting members 66, and the dimensions of the mounting portion 62 are programmed into the computer 50.

As well as the dimensions of the nail 14, the computer 50 is programmed with information relating to the dimensions of a plurality of other work pieces. Thus the targeting apparatus 10 can be used with a plurality of different work pieces.

The targeting apparatus 10 further includes a tool guide 80 which is detachably mounted on the holder 48 spaced from the locating member 54. The tool guide 80 has a tubular body 82 through which a bore 84 is defined.

First co-operating formations, in the form of bayonet fittings 83, are provided on the tubular body 82 to secure the tool guide 80 to the holder 48 at corresponding second co-operating formations on the holder 48.

Tools can be inserted into the bore 84 in the tubular body 82. The tools may be a bladed member 86 (see Figure 2) for cutting through the softer outer region, and a drill guide 88 (see Figure 3) for guiding a drill (not shown) to drill through the harder inner region. The tool guide 80 terminates in a distal end 90 spaced from the holder 48. The tool guide 80 extends parallel to the locating member 54 from the holder 48. The position of the tool guide 80 relative to the locating member 54 is programmed into the computer 50.

Further, the tool guide 80 extends from the holder 48 by a known length, which length is programmed into the computer 50. Thus, the computer 50 can determine the position of the tool guide 80 and the distal end 90 of the tool guide 80 during operation of the co-ordinate measuring machine 26.

The position of the tool guide 80, and of the distal end 90 of the tool guide 80, can be displayed on the screen 52.

In operation, the user inserts the nail 14 into the article 20. The position determining guide 60 is then mounted on the nail 14, with the mounting portion 62 co-operating with the mounting formation 64 on the nail 14.

The holder 48, and hence the arm 28, is then manipulated by the user to engage the locating end portion 58 of the locating member 56 onto the ends of the three projecting members 66.

The position of the locating end portion 58 is registered on the computer 50 on each engagement of the locating end portion 58 with one of the projecting members 66, thereby registering the positions of the ends of the projecting members 66 on the computer 50.

The position and orientation of the nail 14 are then displayed on the screen 52, along with the position and orientation of the tool guide 80, and particularly the distal end 90 of the tool guide. The user can then move the holder 48 along the article 20, and by viewing the screen 52, can see when the tool guide 80 and the distal end 90 is aligned with the first aperture 16.

Upon such alignment, the bladed member 86 is inserted into the tool guide 80 to cut the softer material in the outer region of the article 20. The bladed member 86 is then removed and replaced by the drill guide 88, so that a drill can be inserted into the drill guide 88 to drill through the harder material of the inner region of the article 20.

After drilling of the harder material is completed, the drill guide 88 can then be removed and a screw (not shown) inserted into the aperture 16 in the nail 14, through the holes cut and drilled in the article 20.

The embodiment of the targeting apparatus described herein is suitable for use in a surgical procedure, as described below, but it will be appreciated that the targeting apparatus could be used in many other fields, unrelated to surgery, where it is desired to locate a region of a work piece embedded in an article.

The surgical procedure in question comprises the insertion of a nail 14 in the form of an intramedullary nail into the intramedullary canal of a patient's femur, for example where the femur has been fractured.

After the nail 14 has been inserted into the intramedullary canal, it can be necessary to insert screws into the apertures 16, 22 in the nail 14.

In order to facilitate the insertion of the screws, the targeting apparatus 10 can be used. The surgeon first attaches the position determining guide 60 to the mounting formation 64 on the nail 14 by means of the mounting portion 62, and then engages the locating end portion 58 with the ends of the three projecting members 66 of the position determining guide 60 to register their positions on the computer 50.

Since details of the dimensions of the nail 14 and of the position determining guide are programmed into the computer 50, the computer 50 is able to display on the screen 52 an image of the nail 14, including an image of the apertures 16, 22, relative to the position of the locating member 54.

The surgeon then attaches the tool guide 80 to the holder 48. The dimensions of the tool guide 80 are already programmed into the computer 50, and the computer 50 can display on the screen 52 an image of the tool guide 80.

The surgeon then moves the holder 48 along the patient's leg, and the movement of the tool guide 80 by the holder 48 is displayed on the screen 52, so that the surgeon can follow the movement of the tool guide 80 relative to the nail 14 by observing the screen 52.

The surgeon then manipulates the holder 38 until the screen 52 shows that the tool guide 80 is aligned with one of the first and second apertures 16, 22, and then inserts a bladed member 86, which may be in the form of a scalpel, to cut through the soft tissue to the patient's femur.

The bladed member 86 is then removed from the tool guide 80, and a drill guide 88 inserted in to the tool guide 80 in place of the bladed member 86.

The surgeon then inserts a drill bit (not shown) attached to a suitable drill (not shown) through the drill guide 80 until the drill bit engages the femur. The surgeon then drills through the bone until the drill bit reaches the first or second aperture 16 or 22 in the nail 14. A screw (not shown) can then be screwed into the nail 14. If desired the above process can be repeated for the other of the first and second apertures 16, 22.

Referring to Figures 8 to 12, there is shown a second embodiment of a targeting apparatus, generally designated 110, for targeting a first region 112 of a work piece in the form of a nail 114 (see Figures 9 and 10). The nail 114 has a proximal end 114A and a distal end 114B.

The first region of the nail 114 is provided at the distal end 114B, and defines a first aperture 116. The purpose of the targeting apparatus 110 is to target and locate the aperture 116, so that a suitable screw (not shown) can be inserted through the aperture 116.

The nail 114 also has a second region 118 at the distal end 114B, which defines a second aperture 120. The user may wish to target the second aperture 120 instead of, or as well as, the first aperture 116 for insertion of one or more of the screws.

The nail 114 shown in Figures 9 and 10 is an example of a plurality of nails having different shapes and dimensions.

Referring to Figure 8, the targeting apparatus 110 comprises locating device in the form of a robot arm 121 , which comprises a base 122, which may be mounted on a suitable fixed, rigid support 123. The robot arm 121 comprises a first arm section 124, which extends upwardly from the base 122.

The first arm section 124 has a lower end 124A and an upper end 124B. The first arm section 124 is pivotally mounted at the lower end 124A to the base 122 at a first joint 125. The first arm section 124 is pivotally movable in two dimensions about the base 122, in a horizontal plane, as shown by the arrow A. The robot arm 121 further includes a second arm section 126, which is pivotally mounted by a pivot member 128 on the upper end 124B of the first arm section 124 at a second joint 127. The second arm section 126 is pivotally movable about the first arm section 124 in two dimensions, as shown by the arrow B.

The robot arm 121 also includes a third arm section 130, which is pivotally mounted by a pivot member 132 on the second arm section 126 at a third joint 134. The third arm section 130 is pivotally movable about the second arm section 126 in two dimensions, as shown by the arrow C.

The robot arm 121 includes an end arm section 136, which is pivotally mounted by a pivot member 138 on the third arm section 130 at a fourth joint 140. The third arm section 136 is pivotally movable about the second arm section 126 in two dimensions, as shown by the arrow D.

The end arm section 136 has a proximal end member 142, at which the end arm section is pivotally connected to the third arm section 130. The end arm section 136 also has a distal end member 144, which is pivotally connected to the proximal end member 142 by a pivot member 146 to provide rotation of the distal end member 144 in two dimensions, as shown by the arrow E.

A probe 146 is provided on and extends axially from the distal end member 144. The purpose of the probe 146 is described below.

The robot arm 121 also includes a drive assembly comprising a plurality of drive arrangements 148 are arranged at the first, second, third and fourth joints 125, 1127, 134 and 140 respectively. A further drive arrangement (not shown) is provided at the end arm section 136 to drive the distal end member 144. Each of the drive arrangements comprises an electric motor, and a transmission arrangement to transmit drive from the electric motor to the respective first, second, third and end arm sections 124, 126, 130 and 136.

The targeting apparatus 110 also includes a data processing arrangement 150 in the form of a computer having an associated keyboard. The data processing arrangement 150 is shown schematically in Figure 8.

The data processing arrangement 150 includes a database. The dimensions of the nail 14, and of other nails to be used with the targeting apparatus 110, are stored in the database. The data processing arrangement also includes a controller to control the movement of the arm sections 124, 126 and 130, and the end section 136 by operating the drive arrangements 148. The controller may be suitable software on the data processing arrangement 150.

Referring to Figure 9, there is shown the nail 114, on which is mounted a further component of the targeting apparatus 110, namely a position determining guide 152.

The position determining guide 152 is shown in more detail in Figure 11 , and comprises a mounting portion 154 in the form of a tubular member 155 having a cooperating formation 156. As can be seen from Figures 9 and 10, the proximal end 114A of the nail 114 has a corresponding mounting formation 158.

The mounting formation 158 can cooperate with the cooperating formation 156 to hold the nail 114 on the mounting portion 154 in a predetermined orientation.

A fastening member in the form of a bolt 160 fastens the position determining guide 152 to the proximal end 114A of the nail 114. The bolt 160 is shown in more detail in Figure 12, and comprises a head 162 defining a hexagonal recess 164 for receiving a suitable key having a hexagonal profile, such as an alien key. The bolt 160 further includes a shank 166 having an externally threaded end region 168, which threadably engages internal threads (not shown) at the proximal end 114A of the nail 114.

The position determining guide 152 further includes a carrier to carry the mounting portion 154. The carrier is in the form of a circuit board, 170 and includes three guide means in the form of touch sensitive sensors 172. The circuit board 170 is an operating device for the touch sensitive sensors 172.

The dimensions of the position determining guide 152 are stored on the database, and hence the position of the cooperating formation 152 relative to the touch sensitive sensors 172 is stored on the database, or can be worked out by the data processing arrangement. The dimensions of the nails to be used with the position determining guide 152 are stored on the database.

Hence, when a nail, such as the nail 114 is secured to the position determining guide 152, the position of the first and second apertures 116, 120 relative to the touch sensitive sensors is stored on the database, or can be worked out by the data processing arrangement 150.

In use, the probe 146 on the end arm section 136 is engaged with the three touch sensitive sensors 172, and the position of the probe 146 at each sensor 172 is recorded by the data processing arrangement 150. This recordal of the position of the sensors 172 can be effected by the electrical connection between the circuit board 170 on engagement of the probe 146 with the sensors 172.

Alternatively, the recordal of the aforesaid position can be made manually, for example by the user triggering such recordal by pressing the "return" key on the keyboard. The position of the position determining guide is kept fixed. The controller on the data processing arrangement is then operated to move the robot arm 121 so that the probe 146 is moved to the position of the first or second aperture 116, 120. A suitable screw (not shown) can then be inserted into the aperture 116, 120.

In the embodiment of this invention that is used in surgical procedure described above, the surgeon manipulates the robot arm 121 either manually or by operating the robot arm via the controller on the data processing arrangement 150. The probe 146 is brought into engagement with each of the touch sensitive sensors 172, and the position of the probe 146 is recorded onto the data processing arrangement 150 at each of the sensors 172.

Since the dimensions of the position determining guide 152 and of the nail 114 are stored on the data processing arrangement, the position of the first and second apertures relative to the sensors 172 is stored, or can be worked out, by the data processing arrangement 150.

Thus, the surgeon can then operate the controller on the data processing arrangement 150 so that the robot arm 121 is moved by the controller until the probe 146 is positioned adjacent the patient's leg at the location where the screw should be inserted into the first or second aperture 116, 120.

The apparatus 110 includes a tool guide mounted on a holder. The tool guide and the holder are generally the same as the tool guide 80 and the holder 48 used in the apparatus 10 (see Figures 1 to 3). The tool guide 80 is mounted on a holder 48 which, in turn is mounted on the end arm section 136, adjacent the probe 146, in a similar arrangement to that described above with reference to the first embodiment. The holder 48 used in the embodiment shown in Figures 7 to 12 may differ from the holder shown in Figures 1 to 3 in that the holder 48 may, if desired, be devoid of the handle 47.

In use, the surgeon records on the data processing arrangement 150, the position of the probe 146 in engagement with the sensors 172. The robot arm 121 is then operated so that it moves the probe 146 and the tool guide 80 to the distal end 114B of the intramedullary nail 114.

The data processing arrangement 150 is previously programmed with the relative positions and dimensions of the probe 146 and the tool guide 80. Thus, the controller causes the data processing arrangement 150 to move the robot arm 121 to move the tool guide 80 to the position adjacent the patient's leg in alignment with the first or second aperture 116, 120.

Appropriate cutting and/or drilling tools can then be inserted through the tool guide 80 to cut and/or drill into the patient's leg for the purpose of inserting a screw in the first or second aperture 116 or 120.

The above described second embodiment has the advantage that the robot arm 121 can move a probe automatically to a desired position, thereby allowing a user, such as a surgeon, to carry on further work on a region of a work piece, when the aforesaid region of the work piece is hidden from view.

Thus, in the above exemplary uses of the above described targeting apparatus 10, 110, a surgeon can accurately locate the position of an aperture 116, 120 in an intramedullary nail 14, 114 with minimal damage to the patient's leg.

Claims

1. A targeting apparatus for targeting a preselected region of a work piece, the apparatus comprising a locating device for locating the position and orientation of the work piece, said locating device comprising a locating member, and the targeting apparatus further including a position determining guide mountable on the work piece, wherein the locating device is co-operable with the position determining guide to determine the position and orientation of the work piece, and thereby determine the position and orientation of the aforesaid preselected region of the work piece.

2. A targeting apparatus according to Claim 1 , wherein the locating member has a locating end portion engageable with the position determining guide.

3. A targeting apparatus according to Claim 1 or 2, wherein the locating member comprises a stylus or probe.

4. A targeting apparatus according to Claim 1 , 2 or 3, wherein the locating device includes an arm having a plurality of arm sections, each arm section being connected to at least one further arm section at a respective joint, and the locating member being provided at an end section of the arm.

5. A targeting apparatus according to Claim 4, wherein the arm includes a drive assembly to move the arm sections.

6. A targeting apparatus according to Claim 5, wherein the drive assembly comprises a respective drive arrangement associated with each joint to move the arm sections connected to each other at the respective joint.

7. A targeting apparatus according to Claim 6, wherein the arm sections are movably connected to one another so that the respective drive arrangements can move the arm sections.

8. A targeting apparatus according to Claim 7, wherein the arm sections are connected to one another to be movable relative to each other in two dimensions.

9. A targeting apparatus according to Claim 8, wherein the arm sections are pivotally connected to each other,

10. A targeting apparatus according to any of Claims 5 to 9, wherein the locating device comprises a robot arm.

11. A targeting apparatus according to any of Claims 6 to 12, wherein the locating device comprises a base having a securing arrangement to secure the base to a support in a fixed position relative to the work piece.

12. A targeting apparatus according to Claim 11 , wherein the securing arrangement comprises a clamp to clamp the locating device to the support.

13. A targeting apparatus according to Claim 11 or 12, wherein the arm is movably mounted on the base.

14. A targeting apparatus according to Claim 13, wherein the arm is pivotally mounted on the base.

15. A targeting apparatus according to any of Claims 11 to 14, wherein the locating device comprises a connector to connect the arm to the base.

16. A targeting apparatus according to Claim 15, wherein the connector comprises a sleeve to receive the arm therein, the sleeve being configured to allow rotation of the arm.

17. A targeting apparatus according to any of Claims 6 to 16, wherein the base houses a drive arrangement to drive the arm about the base.

18. A targeting apparatus according to any of Claims 5 to 17, comprising a data processing arrangement, wherein the data processing arrangement comprises a controller to control movement of the locating device, the controller being connected to the drive assembly to control movement of the arm sections.

19. A targeting apparatus according to Claim 18, wherein the data processing arrangement is configured to process data relating to the position and orientation of the position determining guide.

20. A targeting apparatus according to Claim 18 or 19, wherein the data processing arrangement is provided with information relating to the work piece, said information including dimensions of the work piece, and the data processing arrangement is further provided with information relating to the position and orientation of the preselected region relative to the position determining guide on the work piece.

21. A targeting apparatus according to Claim 18, 19 or 20, wherein the targeting apparatus includes a display arrangement to display the movement of the locating device.

22. A targeting apparatus according to any preceding Claim, wherein the position determining guide may comprises a datum indicator, having a mounting portion to mount the position determining guide on the work piece, and the work piece including a mounting formation on which the position determining guide can be mounted.

23. A targeting apparatus according to Claim 22, wherein the position determining guide comprises a fastener to fasten the mounting portion to the mounting formation.

24. A targeting apparatus according to Claim 22 or 23, wherein the mounting portion is configured to co-operate with the mounting formation on the work piece and thereby hold the position determining guide to the work piece at said mounting formation

25. A targeting apparatus according to Claim 22, 23 or 24, wherein the position determining guide comprises at least one guide means, whereby the locating device can co-operate with the, or at least one, guide means to determine the position and orientation of the work piece.

26. A targeting apparatus according to Claim 25, wherein the position determining guide comprises first, second and third guide means.

27. A targeting apparatus according to Claim 25 or 26, wherein the locating member can engage the, or each, guide means to determine the position and orientation of the work piece.

28. A targeting apparatus according to Claim 25, 26 or 27, wherein the, or each, guide means comprises a sensor to sense the locating member.

29. A targeting apparatus according to any of Claims 25 to 29, wherein the position determining guide comprises a carrier for the, or each, guide means, the carrier being attached to the mounting potion, and comprising an operating device for operating the, or each, guide means.

30. A targeting apparatus according to Claim 29, wherein the operating device comprises a circuit board.

31. A targeting apparatus according to any preceding Claim, wherein the targeting apparatus further includes a tool guide to guide a tool towards said preselected region of the work piece.

32. A targeting apparatus according to Claim 31 , wherein the tool guide is mountable on the locating device a predetermined distance from said locating member.

33. A targeting apparatus according to Claim 31 or 32, wherein the tool guide comprises a tube to receive a tool therethrough.

34. A targeting apparatus according to Claim 31 , 32 or 33, including a holder to hold the tool guide, the holder comprising a main portion through which the tool guide can extend, first co-operating formations being provided on the main portion to co-operate with second co-operating formations on the tool guide and secure the tool guide to the main portion.

35. A targeting apparatus according to any of Claims 31 to 34, when dependent, or ultimately dependent upon Claim 18, wherein a dimension of the tool guide and the position of the tool guide relative to the locating member being recorded on the data processing arrangement.

36. A method of targeting a preselected region of a work piece with a targeting apparatus comprising a locating device and a position determining guide, the method comprising arranging the position determining guide on the work piece and moving the locating device to co-operate with the position determining guide to determine the position and orientation of the work piece, and thereby determine the position and orientation of the aforesaid preselected region of the work piece.

37. A method according to Claim 36, wherein the locating device comprises a locating member and the step of moving the locating device comprises moving the locating member so that the locating member engages the position determining guide.

38. A method according to Claim 37, wherein the locating member comprises a locating end portion engageable with the position determining guide, and the step of moving the locating device comprises moving the locating member so that the locating end portion engages the position determining guide.

39. A method according to Claim 37 or 38, wherein the position determining guide comprises at least one guide means, and the step of moving the locating device comprises moving the locating member so that the locating member engages the, or at least one, guide means, and the locating device can co-operate with the, or at least one, guide means to determine the position and orientation of the work piece.

40. A method according to any of Claims 36 to 39, wherein the targeting apparatus comprises a data processing arrangement, and the method comprises inputting to the data processing arrangement said information relating to the position and orientation of the mounting portion on the position determining guide.

41. A method according to Claim 40, wherein the method comprises recording on the data processing arrangement the position of the locating member at engagements of the locating member with the position determining guide.

42. A method according to Claim 40 or 41 , comprising providing the data processing arrangement with information relating to the work piece, said information including dimensions of the work piece, and the method further including providing the data processing arrangement with information relating to the position and orientation of the preselected region relative to the position determining guide on the work piece.

43. A method according to Claim 40, 41 or 42, wherein, when the position determining guide is mounted on the work piece, the co-operation of the locating member with the position determining guide provides information to the data processing arrangement to allow the data processing arrangement to determine the position and orientation of the work piece, and of the aforesaid preselected region, relative to the location device, and the method involves allowing the data processing arrangement to guide the location device to the location of the aforesaid preselected region.

44. A method according to any of Claims 40 to 43 comprising moving the arm so that the locating member engages the position determining guide, and recording on the data processing arrangement the position of the locating member in engagement with the position determining guide, thereby allowing the data processing arrangement to determine the position and orientation of the work piece.

45. A method according to any of Claims 40 to 45, wherein the locating device comprises a tool guide to guide a tool towards said preselected region of the work piece and the method includes the data processing arrangement moving the arm until the tool guide is aligned with the preselected region of the work piece.

46. A method according to Claim 45, wherein the work piece is embedded in an article, and the method comprises inserting a tool into the tool guide, and allowing the locating device to be moved until the tool guide is aligned with the aforesaid preselected region.

47. A method according to Claim 45 or 46, wherein, the method includes using said tool during removal of material from said article to provide access to the aforesaid preselected region of the work piece.

48. A method according to any of claims 40 to 47, wherein the data processing arrangement comprises a control means for controlling the locating device, and when the position and orientation of the work piece has been determined by the data processing arrangement, the method comprises operating the control means to actuate the drive assembly and move the locating device to the preselected position.

49. A method according to Claim 48, wherein the preselected position can then be marked and material removed from the article to allow access to the work piece.

50. A method according to Claim 45, 46 or 47, wherein the work piece is embedded in an article of a second material that is surrounded or embedded in a first material that is softer than the second material, and the method comprises inserting a first tool into the tool guide, and when the tool guide is aligned with the aforesaid preselected region, the method comprises removing the first material with the first tool, and then inserting a second tool into the tool guide and removing the second material using the second tool to provide access to the work piece.

51. A method according to Claim 50, wherein the first tool comprises a bladed tool to cut through the first material, and the second tool comprises a drill guide for a drill bit to drill through the second material.

52. A targeting apparatus substantially as herein described with reference to Figures 1 to 7 of the accompanying drawings.

53. A targeting apparatus substantially as herein described with reference to Figures 8 to 12 of the accompanying drawings.

54. A method of targeting a preselected region of a work piece with a targeting apparatus substantially as herein described with reference to Figures 1 to 7 of the accompanying drawings.

55. A method of targeting a preselected region of a work piece with a targeting apparatus substantially as herein described with reference to Figures 8 to 12 of the accompanying drawings.