WO2020128881A1

WO2020128881A1 - Orthopaedic tool

Info

Publication number: WO2020128881A1
Application number: PCT/IB2019/060991
Authority: WO
Inventors: Thomas Blignaut NAUDE
Original assignee: Naude Thomas Blignaut
Priority date: 2018-12-18
Filing date: 2019-12-18
Publication date: 2020-06-25

Abstract

This invention relates to an orthopaedic tool, and more particularly, but not exclusively, to an orthopaedic tool for inserting and extracting screws in a patient. In accordance with this invention there is provided an orthopaedic tool comprising an elongate body having a blade formation (4) at a first end thereof and an engagement means (5) extending from the blade.

Description

ORTHOPAEDIC TOOL

FIELD OF THE INVENTION

This invention relates to an orthopaedic tool, and more particularly, but not exclusively, to an orthopaedic tool for inserting and extracting screws in a patient.

BACKGROUND TO THE INVENTION

Poly axial screws are used to a fix a rod or plate to bone of a patient.

A prior art poly axial screw 13 is shown in figure 3. The screw has a screw threaded shaft 12 and a rotatable screwhead 11 at a top end of the shaft 12. The screwhead 11 and shaft 12 may be attached to each other with a ball joint 29. This allows the head 11 to be rotatable to several different axes relative to the shaft 12.

The screwhead is generally right-circular. The screwhead 11 has a centrally located co-axially extending blind bore extending into a top surface thereof. An inside surface of the bore includes a screw thread 10. The screwhead 11 , with the bore therein, in top view, defines a ring-shaped formation having a wall thickness between the bore and outer surface of the head 11. The ring-shaped formation has a depth equal to the depth of the bore. Diametrically opposed, radially extending and aligned slots 32, are located in the wall of the ring. The above describes the general configuration of poly axial screws 13. The dimensions and specific configuration of the screw shaft 12, head 11 , bore and slots 32 differ between different manufacturers.

A screwdriver 28 used for screwing the screw 13 is specific to a corresponding screw manufacturer. An example of such a prior art screwdriver 28 is shown in figures 1 and 2. The screwdriver 28 has a handle 24, a screwdriver shaft 27 and a front end 25 which includes engagement formations in the form of opposing protrusions 2 and a tip 31 to engage with a prior art screw 13, a cross section of which is shown in figure 3. The protrusions 26 engage in the slots 32 of the screwhead 11 and the tip 31 with a complementary receiving recesses 30 in the top of the shaft 12 of the screw 13. The above configurations enable the screwhead 11 to turn as a unit with the shaft 12 of the screw 13. Figure 4 shows the screwdriver 28 engaged with the screw 13.

With reference to figures 5 to 7, an elongate rod 27a fits into the two opposing slots 32 of the screwhead 11 , so that it extends transversely through the screwhead 11. A nut 7 in the form of a short, thick disc has an outer screw thread 9. The nut has engagement formations 8 similar to the engagement formations 30 in the top end of the shaft 12 of the screw 13. A second screwdriver such as screwdriver 17 shown in figures 12 and 13 has a handle 20, shaft 19 and tip 18 and is used to screw the nut 7. The tip 18 of the screwdriver 17 is complementary shaped to the engagement formations 8 in the top of the nut 7, to facilitate screwing and unscrewing of the nut 7. In practice, the tip 18 of the screwdriver 17 is interchangeable to facilitate the use of the screwdriver 17 in different engagement formations 8 of nuts supplied by different manufacturers. Typically, a set of interchangeable tips 18 is supplied.

With the rod 27a inserted into the screwhead 11 as described above, the nut 7 can be screwed into the screw threaded bore 10 of the screwhead 11 using screwdriver 17. The nut 7 is screwed into the head 11 until it bears against the rod 27, which in turn, is forced to seat on the upper surfaces of the engagement formations 30 on top of the shaft 12 of the screw 13. In this manner, the shaft 12, screwhead 11 and rod 27 are immovably secured with respect to each other. Figure 7 shows the poly axial screws 13 and rods 27a in use to support part of a spine 33 of a patient.

The screws 13 are screwed into pre-drilled holes in different parts of the spine 33 and a rod 27 connects the screws 13, through their screwheads 11. When the nut 7 is tightened as described above, the corresponding section of the spine 33 is rigidly supported by screw 13 and rod 27 combinations.

For removal of the screws, the nut 7 and the rod 27a must be removed where after the screw 13 can be unscrewed, using the manufacturer specific screwdriver 17 or specific screwdriver tip 18. Herein lies a difficulty. The specific manufacturer screwdriver may not be readily available during surgery. Furthermore, it may not be possible to establish, through x-rays or other physical investigation, what make of screw was inserted during prior surgery in order to ensure that the correct screwdriver is available during surgery. In addition, the patient may not know or have records of what make of screw was used. In such event, the tissue and/or spine of a patient will suffer unnecessary damage if incorrect tools are used to remove a screw.

OBJECT OF THE INVENTION

It is an object of this invention to provide an orthopaedic tool which, at least partially, alleviates some of the abovementioned difficulties.

SUMMARY OF THE INVENTION In accordance with this invention there is provided an orthopaedic tool comprising an elongate body having a blade formation at a first end thereof and an engagement means extending from the blade.

There is provided for the orthopaedic tool to have a socket receiving formation at a second end thereof.

There is provided for the engagement means to extend normally from a surface of the blade formation.

A still further feature of the invention provides for the engagement means to be a rod.

There is also provided for the blade to be concave and to be an extension of a tubular upper part of the orthopaedic tool.

The socket receiving formation has a screwdriver receiving opening therein which is at least partially aligned with an elongate opening defined by the tubular section of the orthopaedic tool.

The invention extends to a counter torque tool for securing the orthopaedic device in a desired position whilst operating a screwdriver extending through the screwdriver receiving opening and the tubular section of the orthopaedic tool. The invention further extends to a method of screwing a screw into or out of a body part of a patient comprising the steps of:

- inserting an engagement means of an orthopaedic tool in a slot of a head of a poly axial screw; and

- operating a securing means to secure the head of the poly axial screw, a shaft of the poly axial screw and the engagement means securely relative to each other.

There is provided for the securing means to be a nut having an outer screw thread engageable with complementary screw thread on an inner bore of the screw head.

There is further provided for the engagement means to be a rod extending through the screw head and at least partially into the bore in the screw head.

The rod may extend through one or more holes or slots in the screw head.

These and other features of invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention is described below, by way of example only, and with reference to the drawings in which: Figure 1 shows a side view of a prior art screwdriver for a poly axial screwhead;

Figure 2 shows a perspective view of the screwdriver of figure 1 ;

Figure 3 shows a cross-sectional side view of a prior art poly axial screw;

Figure 4 shows the screwdriver of figure 1 and 2 engaged with the poly axial screw of figure 3;

Figure 5 shows a cross-sectional side view of a poly axial screw of figure

3, a prior art nut and a prior art rod;

Figure 6 shows a perspective view of the poly axial screw of figures 3 and

5, nut and rod of figure 4;

Figure 7 shows poly axial screws, nuts and rods fixed to a spinal cord in accordance with the invention;

Figure 8 shows a front-right perspective view of an orthopaedic tool;

Figure 9 shows a front-left perspective view of the orthopaedic tool of figure 7;

Figure 10 shows a front view of the orthopaedic tool of figures 8 and 9; Figure 1 1 shows a side view of the orthopaedic tool of figures 8 to 10;

Figure 12 shows a screwdriver, a counter torque tool in accordance with the invention, the orthopaedic tool of figures 8 to 1 1 , nut and poly axial screw assembled;

Figure 13 shows the screwdriver, counter torque tool in accordance with the invention, orthopaedic tool, nut and poly axial screw of figure 1 1 in exploded view;

Figure 14 shows a socket, the orthopaedic tool, nut and the poly axial screw; and Figure 15 shows the socket engaged with the orthopaedic tool of figure 13.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the drawings, an orthopaedic tool in accordance with one example of this invention is generally indicated by reference numeral 1 and a counter torque tool, also in accordance with one example of this invention, is generally indicated by reference numeral 14. The orthopaedic tool 1 consists of an elongate body having socket and counter torque tool receiving formations 2 at an operatively upper end thereof. A tubular section 3 extends coaxially from the torque receiving formations 2, co-axially with an opening in an upper end of the torque receiving formations 2. In other words, an axial bore extends co-axially through the tool 1.

Towards the second or opposite end of the body, the tubular section 3 is cut away in an axial direction to leave a concave blade 4. The concave blade 4, at its outer end has a rod 5 extending normally inwardly from the blade 4. The rod 5 is thus transverse in an extended line of the main axis of the orthopaedic tool.

The counter torque tool 14 includes a handle 16 and a coaxially extending shaft that terminates in a claw 15. The claw 15 has engagement formations to engage with the counter torque engagement formations 2 on the orthopaedic tool 1. The claw 15 is C-shaped and the engagement formations are inwardly extending protrusions at the free ends of the“C”. The claw 15 has upper stopper tabs to prevent the claw 15 and thus the counter torque 14 to slide downwards along the engagement formations on the orthopaedic tool 1.

In use, when a screwdriver such as the screwdriver of figures 1 and 2 is not available to un-screw (or to screw in) a poly axial screw, in other words, when a screwdriver having engagement formations sufficient to screw in or to unscrew a poly axial screw is not available, the orthopaedic tool 1 can be used instead. In effect, the rod 5 of the orthopaedic tool replaces the rod 27a which is used to support a section of a patient’s spine. However, with the rod 5 being much shorter than the rod 27 and attached to an elongate and normally extending tool 1 , the screw may be rotated by rotating the tool 1. Typically, the rod 5 will be of a length sufficient so that the nut 7 may be used to secure it in the screw head 11 in similar fashion as when one secures the rod 27 in the screw head. The rod is thus forced onto the upper surfaces of the receiving recesses 30 at the upper end of the shaft 12 of the screw thus securing the rod 5, screw head 11 and shaft 12 securely relative to each other. With the rod of the tool thus secured in the screw head and on the upper surfaces of the recesses 30, the screw may be screwed in or unscrewed as may be required. In addition, with the tool secured in this position, a screwdriver may be inserted through the central co-axial bore of the tool 1 to selectively fasten or remove the nut 7 from the screw head. This will of course selectively fasten or loosen rod 5. When fastening of or removing the nut, the counter torque may be attached to the tool as is shown in figure 12 to ensure that the tool and thus the screw does not rotate when fastening or removing the nut 7.

It is envisaged that the tool described herein will be convenient to use in that it provides a generic tool for use with different types and makes of poly axial screws. The size of the rod is not critical and may be made so that it can be used with many different configurations of poly axial screws, the screw heads and upper shaft ends. The counter torque tool is also convenient to ensure that the tool does not rotate when fastening or removing the nut 7. The invention is not limited to the precise details as described herein. It will be appreciated by those skilled in the art that many embodiments are possible without departing from the scope of the invention.

Claims

1. An orthopaedic tool comprising an elongate body having a blade formation at a first end thereof and an engagement means extending from the blade.

2. An orthopaedic tool as claimed in claim 1 in which the body is tubular with part of the wall of the tube at its first end cut-away to forms the blade.

3. An orthopaedic tool as claimed in claim 1 in which the orthopaedic tool has at least one receiving formation at a second end thereof.

4. An orthopaedic tool as claimed in claim 3 in which the receiving formation is a socket receiving formation for engaging with a socket tool.

5. An orthopaedic tool a claimed in any one of the preceding claims in which the engagement means extends normally from a surface of the blade formation.

6. An orthopaedic tool as claimed in any one of the preceding claims in which the engagement means is a rod.

7. An orthopaedic tool as claimed in any one of the preceding claims in which the blade is concave, being part of a wall of a tube that is cut away to forms the concave blade.

8. An orthopaedic tool as claimed in any one of the preceding claims in which the blade is an extension of a tubular operatively upper part of the orthopaedic tool.

9. An orthopaedic tool as claimed in claim 6 in which the socket receiving formation has a screwdriver receiving bore.

10. An orthopaedic tool as claimed in claim 1 in which the orthopaedic tool is a counter torque tool for securing the orthopaedic device in a desired position whilst operating a screwdriver extending through the screwdriver receiving opening and the tubular section of the orthopaedic tool.

11. In accordance with this invention there is provided a method of screwing a screw into or out of a body part of a patient comprising the steps of:

12. An orthopaedic tool as claimed in claim 9 in which the securing means is a nut having an outer screw thread engageable with complementary screw thread on an inner bore of the screw head.

13. An orthopaedic tool as claimed in claim 9 in which the engagement means is a rod extending through the screw head and at least partially into the bore in the screw head.

14. An orthopaedic tool as claimed in claim 11 in which the rod extends through one or more holes in the screw head.

15. An orthopaedic tool as claimed in claim 12 in which the rod extends through one or more slots in the screw head.