WO2014063197A1

WO2014063197A1 - A surgical instrument

Info

Publication number: WO2014063197A1
Application number: PCT/AU2013/001233
Authority: WO
Inventors: Robert Lye
Original assignee: Inertial Orthopaedic Navigation Solutions Pty Ltd
Priority date: 2012-10-25
Filing date: 2013-10-25
Publication date: 2014-05-01

Abstract

In one aspect, the invention provides a surgical instrument for assisting in the removal of an acetabular cup implanted in a patient. The instrument comprises a body including a head portion arranged to locate at least partially within an acetabular cup. The instrument also includes at least one cutting device arranged to cut around the acetabular cup, wherein the cutting device is arranged to substantially cut around the outer periphery of the acetabular cup without requiring the body to move through a corresponding path.

Description

A SURGICAL INSTRUMENT

Technical Field

[0001 ] The present invention relates to a surgical instrument. Embodiments of the invention relate generally, but not exclusively, to a surgical instrument arranged to assist in the removal of an acetabular cup from the hip of a patient during hip replacement surgery.

Prior Art

[0002] It is to be noted that a reference to prior art herein is not an admission that the prior art is common general knowledge to a person skilled in the art or any other person.

[0003] Hip replacement surgery is a common surgical procedure. It is estimated that in 201 1 approximately 285 000 hip replacement procedures were performed in the US alone. However, while hip replacement surgical techniques are well known and understood, hip replacement continues to be a very invasive procedure which requires extensive incisions that potentially expose a patient to infection.

[0004] There are several hip replacement incision techniques that have been developed over time. The choice of incision technique is largely dictated by the personal preference of a surgeon. Each technique has advantages and disadvantages. As a general rule, techniques that require a larger incision interval (opening) provide better access to the hip and hip socket, but also increase the risk of infection and potentially lengthen healing time. Techniques that require a smaller incision interval (opening) provide poorer access to the hip and hip socket, but potentially decrease the risk of infection and shorten healing time.

[0005] There is little clear evidence in the literature that one technique is substantively better than another (in terms of dislocation rates, which is the major complication of the surgery), but it has been suggested surgeons favour either an anterolateral or posterior technique, which both provide relatively better access to the relevant surgical site. Both of these techniques require fairly extensive incision intervals, which, while making the procedure more straightforward for the surgeon, arguably increase the risk of infection. [0006] There is also available an anterior approach. The anterior approach requires an incision interval between the sartorius muscle and tensor fascia latae. The anterior approach provides the advantage of requiring a smaller opening than the more common anterolateral or posterior technique. However, given the relatively small opening provided by this technique, the hip replacement procedure is relatively more difficult to perform, particularly with conventional surgical tools.

[0007] In some cases, such as when a previously implanted prosthetic hip needs to be removed, the manner in which the incision occurs is fundamentally identical, but there is some difference in technique, in that the prosthetic hip replacement needs to be removed. This requires different tools and a modified procedure.

[0008] In one particular step of replacing a previously implanted prosthetic hip joint, there is a need to extract the previously implanted acetabular cup. The acetabular cup is a component which is placed into the acetabulum (hip socket). To remove the acetabular cup, an acetabular cup removal instrument is used. To operate such an instrument correctly and easily, a large incision is generally required.

Summary of Invention

[0009] In a first aspect, the invention provides a surgical instrument for assisting in the removal of an acetabular cup implanted in a patient, comprising:

a body including a head portion arranged to locate at least partially within an acetabular cup, at least one cutting device arranged to cut around the acetabular cup; wherein the cutting device is arranged to substantially cut around the entire outside of the acetabular cup without requiring the body to move through a corresponding path.

[001 0] In a second aspect, the present invention provides a surgical instrument comprising:

a body including a head portion in connection with a handle portion via a connecting portion;

wherein the connecting portion includes an offset portion having at least one bend such that the head portion and the handle portion define a substantially straight line. [001 1 ] In one embodiment, the head portion is arranged to locate at least partially within an acetabular cup implanted in a patient.

[001 2] In one embodiment, the head portion further includes a cutting device arranged to substantially cut around an outer portion of the acetabular cup.

[001 3] In one embodiment, the head portion is detachable from the surgical instrument.

[0014] In one embodiment, the head portion is of a substantially spherical shape.

[001 5] In one embodiment, the cutting device is a blade.

[001 6] In one embodiment, the blade is detachable from the instrument.

Brief Description of the Drawings

[001 7] The invention will now be described by way of example only with reference to the following drawings in which:

Figure 1 illustrates a perspective view of an embodiment of a surgical instrument in accordance with the invention;

Figure 2 illustrates the embodiment in Figure 1 in top view;

Figure 3 illustrates the embodiment in Figure 1 in a side view;

Figure 4 illustrates a perspective view of the head portion of the embodiment in Figure 1 ;

Figure 5 illustrates a cut away diagram illustrating use of the embodiment in

Figure 1

Figures 6A illustrates another embodiment of a surgical instrument in accordance with invention;

Figure 6B illustrates a perspective view of the embodiment of Figure 6A;

Figure 6C illustrates a side view of the embodiment of Figure 6A;

Figure 6D illustrates a perspective view of the head portion of the embodiment of Figure 6A; Figure 7 A illustrates a top view of yet another embodiment of a surgical instrument in accordance with the invention;

Figure 7B illustrates a perspective view of the embodiment in Figure 7A;

Figure 7C illustrates a side view of the embodiment in Figure 7A;

Figure 7D illustrates a perspective view of the head portion of the embodiment in Figure 7A;

Figure 8A illustrates yet another embodiment of a surgical instrument in accordance with the invention;

Figure 8B illustrates a perspective view of the embodiment in Figure 8A; and

Figure 8C illustrates a side view of the embodiment in Figure 8A.

Description of Embodiments

[001 8] It is to be noted where possible features common to the various embodiments illustrated in the drawings are referred to in each drawing by a respective common feature number.

[001 9] An embodiment of a surgical instrument 10 in accordance with the invention is illustrated in Figures 1 to 8A inclusive.

[0020] The surgical instrument 10 is arranged to be used in the removal of an acetabular cup from the hip of a patient during hip replacement surgery. In more detail, the surgical instrument, in one embodiment, comprises a body including a head portion arranged to locate at least partially within an acetabular cup and at least one cutting device arranged to cut around the periphery of the acetabular cup. The cutting device is arranged to substantially cut around the outer periphery of the acetabular cup without requiring the body of the instrument to move through a corresponding path.

[0021 ] Referring to Figures 1 to 8C, the surgical instrument 10 includes a head portion 12, which is described in more detail below. The head portion 1 2 is connected to a handle portion 14 via a connecting portion 1 6. The connecting portion 16 comprises an offset portion generally denoted by numeral 18. The offset portion, in the embodiments shown in Figures 1 to 7D, includes two bends generally denoted by numerals 20 and 22, such that the head portion 12 and the handle portion 14 define a substantially straight line, and the bend generally denoted by numeral 20 is approximately 45 degrees relative to the straight line defined by the head portion 12 and the handle portion 14.

[0022] The head portion 12 includes at least one blade 24 which is removably attached to the head portion 1 2 by an attachment portion which comprises corresponding male and female parts that slide into engagement and are securely held by a fixing device (not shown). In one embodiment as shown in Figures 1 to 4, there are provided three equally spaced attachment portions (denoted by 26 and 28, third attachment portion not shown) such that three blades (denoted by 24, other two blades not attached in Figures 1 to 4) may be removably attached to the head portion 12. It will be understood that the exact length, shape and cutting surface of the blades may be varied, as required for different size acetabular cups.

[0023] The head portion 1 2 further includes a locating ball attachment portion 30 arranged to removably receive a locating ball 32 (locating ball not shown in Figures 1 to 4 or 6A through to 8C), such that the locating ball 32 is securely but removably attached to the surgical instrument 10. It will be understood that different size locating balls may be provided depending on the acetabular cup implanted in a patient. The surgeon or other user may remove the locating ball and attach a different size locating ball, as required for each surgical procedure and each patient.

[0024] In use, the surgical instrument 10 is arranged to assist in the removal of an acetabular cup from a patient during a hip replacement procedure. The general manner in which the acetabular cup removal instrument is used will now be described, to assist a person skilled in the art to better understand the structural and functional aspects of the surgical instrument 10. However, it will be understood that this general description of one technique for using the acetabular cup removal instrument is provided for illustrative purposes and should not be construed as limiting on the embodiment or the broader inventive concepts described and claimed herein.

[0025] Referring to Figure 5, the acetabular cup removal instrument 10 is arranged to be inserted into an open incision 50 in a patient 52. The shaded area in Figure 5 denotes the hip area of a patient. [0026] The locating ball 32 is arranged to guide and correctly locate the instrument into the previously implanted acetabular cup 54, to provide a guide for the blade(s) 24. As the incision in the patient is at an acute angle relative to the orientation of the acetabular cup, prior art acetabular cup removal instruments, which do not have an offset connecting portion, cannot be used with oblique anterior incisions.

[0027] The offset connecting portion in accordance with the disclosed embodiment, however, allows the locating ball 32 to correctly align with the acetabular cup, while simultaneously allowing the surgeon to 'turn' the handle of the instrument in a conventional manner (i.e. in a manner akin to the prior art instrument) to effect a cut around the outer periphery of the acetabular cup.

[0028] In more detail, using a technique of axial rotation, the surgeon can use the blade(s) 24 to cut a channel around the outer periphery of the acetabular cup to thereby cut the acetabular cup away from surrounding hip bone and tissue. This cutting in turn detaches the acetabular cup from the patient and allows removal of the acetabular cup from the patient.

[0029] Depending on the size of the acetabular cup and the degree of bonding of the acetabular cup to the patient's hip bone and surrounding tissue, different size blades may be used to effect deeper or shallower cuts, as necessary.

[0030] The ability to utilise different size blades is provided by the spaced attachment portions, which allow for the interchange of blades on the head portion. It will be understood that a shorter "thicker" (i.e. more sturdy) blade may be used to provide an initial cut, whereas a longer "thinner" (less sturdy) blade may be used to make a subsequent cut. Such variations of technique are within the purview of a person skilled in the art.

[0031 ] As may be seen in Figure 5, the relative angle of the surgical instrument relative to the acetabular cup and the oblique angle of the incision restricts the free rotation of the device. As such, in the example shown, the device may only be rotated through an angle of approximately 120 degrees before the connecting portion interferes with the incision.

[0032] Advantageously, to overcome this issue, the surgical instrument 10 is provided, in one embodiment (as shown in Figures 1 to 4), with three equidistantly spaced blades such that the head portion 1 2, when placed in an oblique cut in a patient's hip, can be turned through the angle of approximately 120 degrees but perform a cut that runs along the entire outer circumference of the acetabular cup, to effect removal of the acetabular cup with only one rotation of approximately 120 degrees. As such, the head can effect a circular cutting motion of approximately 360 degrees (a full circle) while the body and handle of the instrument is only rotated through 120 degrees. That is, there is no need for the body to follow a corresponding path with the blade.

[0033] It will be understood that the use of less than three blades or more than three blades falls within the purview of the broader inventive concept described herein and that as the number of blades is increased, the degree through which the handle needs to be turned will decrease. For example Figures 6A to 6D and Figures 7A to 7D show a surgical instrument 10 which includes a single blade 24. Correspondingly, Figures 8A through 8C show an instrument 10 which includes two blades 24. It will be understood that such variations are within the purview of a person skilled in the art.

[0034] Turning specifically to Figures 8A through 8C, there is further shown a second embodiment of the invention which has a differently shaped handle portion. The device of Figures 8A through to 8C includes a curved handle portion 16 and includes dual handles 60 which allow the user to exert greater force and control by providing two handles that are substantially perpendicular to each other, such that one handle may be used to locate, orient and stabilise the cutting device on the instrument, while the other handle may be used to apply substantive pressure by the user to more effectively rotate the instrument.

[0035] It will be understood that the exact shape of the handle and the connecting portion and the number of handles provided on a device may vary and such variations are within the purview of a person skilled in the art.

[0036] It will also be understood that a single rotating blade (operated manually or via some means of providing power, such as an electric or magnetic motor) may be used in place of a plurality of fixed blades. Such variations are within the purview of a person skilled in the art.

[0037] As such, by using an instrument in accordance with an embodiment of the invention described herein, an oblique cut (in keeping with an anterior surgical technique) can be used to remove an acetabular cup. Unlike a prior art instrument, there is no need to turn the handle by 360 degrees to effect a 360 degree circular cut around the outer circumference of the acetabular cup.

[0038] For the purposes of the invention and embodiments described herein, it will be understood that the terms "outer circumference of the acetabular cup" and "outer portion of the acetabular cup' ^' refer generally to the convex surface of the acetabular cup.

[0039] The invention has been described by way of example only with reference to preferred embodiments which is not intended to introduce limitations on the scope of the invention. It will be appreciated by persons skilled in the art that alternative embodiments exist even though they may not have been described herein which remain within the scope and spirit of the invention as broadly described herein.

[0040] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

CLAIMS:

1 . A surgical instrument for assisting in the removal of an acetabular cup implanted in a patient, comprising:

a body including a head portion arranged to locate at least partially within an acetabular cup, at least one cutting device arranged to cut around the acetabular cup; wherein the cutting device is arranged to substantially cut around the outer periphery of the acetabular cup without requiring the body to move through a corresponding path.

2. A surgical instrument comprising:

wherein the connecting portion includes an offset portion having at least one bend such that the head portion and the handle portion define a substantially straight line.

3. A surgical instrument in accordance with Claim 2, wherein the head portion is arranged to locate at least partially within an acetabular cup implanted in a patient.

4. A surgical instrument in accordance with Claim 3, wherein the head portion further includes at least one cutting device arranged to substantially cut around an outer portion of the acetabular cup.

5. A surgical instrument in accordance with Claim 4, wherein the head portion is detachable from the surgical instrument.

6. A surgical instrument in accordance with Claim 4 or Claim 5, wherein the head portion is of a substantially spherical shape.

7. An instrument in accordance with any one of the preceding claims, wherein the cutting device is a blade.

8. An instrument in accordance with Claim 7, wherein the blade is detachable from the instrument.