WO2012024271A2

WO2012024271A2 - Patient-matched features for aligning biomedical implants

Info

Publication number: WO2012024271A2
Application number: PCT/US2011/047876
Authority: WO
Inventors: David C. Kelman; Jeffrey A. Sharp; Thomas S. Wolfe
Original assignee: Smith & Nephew, Inc.
Priority date: 2010-08-16
Filing date: 2011-08-16
Publication date: 2012-02-23
Also published as: WO2012024271A3

Abstract

Patient-matched devices according to certain embodiments may include a patient-matched surface that generally conforms to a portion of the patient's anatomy, and an alignment mechanism that is positioned at a fixed orientation with respect to the patient-matched surface. In some embodiments, the alignment mechanism is an alignment post extending away from the patient-matched surface along a predetermined axis. This axis may be pre-operatively determined to correspond to (or at least indirectly reflect) the proper orientation of surgical instruments and/or implants that are used in the surgery. An alignment base and platform may selectively couple to the patient-matched device and other instruments (such as a reamer or an impactor). The surgeon may use alignment indicators on the alignment platform to ensure that the proper orientation is maintained throughout the surgery.

Description

PATIENT-MATCHED FEATURES FOR ALIGNING BIOMEDICAL IMPLANTS CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 61/374,098, filed August 16, 2010 and U.S. Provisional Application No. 61/415,028, filed November 18, 2010. The disclosure of each prior application is incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0002] The present invention relates generally to surgery and more particularly to orthopaedic instruments for use in bone reperation.

[0003] Devices and methods are described herein for implanting and aligning biomedical implants. Such devices may include or be used with components having patient-matched surfaces that generally conform to portions of a patient's anatomy, and other patient-matched features that are used to align surgical instruments and/or implants.

RELATED ART

[0004] A surgeon may use a variety of surgical instruments when performing a hip arthroplasty to implant an acetabular cup into a patient's acetabulum (or otherwise, when performing other orthopaedic surgeries to implant a biomedical device into a patient's anatomy). For example, the surgeon may use a reamer (or other cutting device) to mill out the acetabulum and thus form a socket within which an artificial cup can be anchored. An impactor also may be used to drive the cup into place within the acetabulum. When operating, the surgeon must take care that the instruments are oriented as precisely as possible, so that the acetabular cup will ultimately be positioned and oriented as intended with the greatest possible precision. Otherwise, if the acetabular cup is not properly positioned (for example, if it has too shallow or too high of a cup inclination angle), the patient may experience excessive wear on the acetabular cup or components used with the acetabular cup, dislocation, impingement, limited ranges of motion, infection, or rejection of the implant. Improper alignment may be more prone to occur if the surgeon performs the surgery freehanded.

SUMMARY OF THE INVENTION

[0005] Patient-matched devices according to certain embodiments may include a patient- matched surface that generally conforms to a portion of the patient's anatomy, and an alignment mechanism that is positioned at a fixed orientation with respect to the patient-matched surface. In some embodiments, the alignment mechanism is an alignment post extending away from the patient-matched surface along a predetermined axis. This axis may be pre-operatively determined to correspond to (or at least indirectly reflect) the proper orientation of surgical instruments and/or implants that are used in the surgery. An alignment base and platform may selectively couple to the patient-matched device and other instruments (such as a reamer or an impactor). The surgeon may use alignment indicators on the alignment platform to ensure that the proper orientation is maintained throughout the surgery. While for convenience, the devices and methods shown and described are generally shown as configured for use in procedures on a patient's acetabulum, it is anticipated that the same principals may be applied to surgical instruments and implants configured for use in other procedures.

[0006] There is provided a surgical instrument for use in hip arthroplasty. The surgical instrument comprising: a patient matched device having a base portion and an alignment post, the base portion having a patient matched surface; an alignment base removably attached to the patient matched device; and at least one alignment indicator operatively connected to the alignment base. In some embodiments, the at least one alignment indicator is integral with the alignment base. In one embodiment, the alignment post comprises a keyed portion and a tip. In another embodiment, the alignment post extends along an axis that reflects a pre-operatively determined desired orientation. In still another embodiment, the alignment post and the base portion are monolithic. In yet another embodiment, the base portion is hollow. In another embodiment, only select areas of the base portion comprise the patient matched surface. In still another embodiment, at least a portion of the patient matched surface is textured. In yet another embodiment, the at least one indicator comprises a bubble level. In one particular embodiment, the at least one indicator comprises a 3-axis electronic accelerometer. In another embodiment, the at least one indicator comprises an emitter. In still another embodiment, the alignment base comprises a body, a first prong, and a second prong. In yet another embodiment, the first prong and the second prong define a recess. In one embodiment, the surgical instrument further comprises an alignment platform removably attached to the alignment base, and the at least one indicator is integral with the alignment platform. In still another embodiment, the alignment base comprises a socket that receives a ball associated with the alignment platform.

[0007] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS [0008] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the written description serve to explain the principles, characteristics, and features of the invention. In the drawings:

[0009] FIGS. 1A-C illustrate various views of one embodiment of a patient-matched device comprising at least one patient-matched surface and an alignment post.

[0010] FIGS. 2A and B illustrate various views of one embodiment of an alignment base.

[0011] FIG. 3 illustrates a perspective view of one embodiment of an alignment platform comprising at least one alignment indicator.

[0012] FIG. 4A and B both illustrate a patient-matched device (such as in FIGS. 1A-C) inserted within a patient's acetabulum. FIG. 4A shows an alignment base (such as in FIGS 2A and B) and an alignment platform (such as in FIG. 3) approaching the patient-matched device, whereas FIG. 4B illustrates an alignment base and an alignment platform coupled to the patient- matched device.

[0013] FIG. 5 illustrates a perspective view of one embodiment of a reamer.

[0014] FIG. 6 illustrates a perspective view of one embodiment of a handle comprising an alignment post that may be coupled to the reamer in FIG. 5.

[0015] FIG. 7 illustrates a reamer (such as in FIG. 5) inserted within a patient's acetabulum and coupled to a handle (such as in FIG. 6), an alignment base (such as in FIGS 2A and B), and an alignment platform (such as in FIG. 3).

[0016] FIG. 8 illustrates a perspective view of an acetabular cup and an impactor. [0017] FIG. 9 illustrates an acetabular cup and an impactor (such as in FIG. 8) inserted within a patient's acetabulum and coupled to an alignment base (such as in FIGS 2A and B) and an alignment platform (such as in FIG. 3).

[0018] FIG. 10 schematically illustrates a method according to certain embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following description of the drawings is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. FIGS. 1A-C illustrate one embodiment of a patient- matched device 10 that may be coupled to an alignment base 30 (as shown in FIGS. 2A and B). In certain embodiments, the patient-matched device 10 comprises a base portion 12 and an alignment post 16 extending therefrom. The alignment post 16 may comprise a keyed portion 18 and a tip 20. The alignment post 16 extends along an axis Al. Axis Al, and its relationship to the patient-matched surface 14 of the base portion 12 (discussed below), may be pre-operatively determined to reflect a desired orientation of the surgical instruments and/or implants used in the procedure. In some embodiments, axis Al corresponds to the desired inclination and anteversion angles of certain instruments and/or implants relative to a patient's pelvic bone, including an acetabulum of the pelvic bone. The alignment post 16 may be integrally formed with the base portion 12, or may be formed separately and subsequently coupled to the base portion 12. The base portion 12 is shown as a solid body in FIGS. 1A-C, but in other embodiments, the base portion 12 may be "hollow" such that it resembles a cup or a bowl. Additionally, the base portion 12 may comprise a continuous surface (as in the figures), or a discontinuous surface.

[0020] In certain embodiments at least a portion of the base portion 12 comprises a patient-matched surface 14 that substantially conforms to at least a portion of the patient's anatomy. Specifically, the patient- matched surface 14 may conform or otherwise fit to the anatomy in one position and orientation only (for example, only in the "12 o'clock position" within the acetabulum) rather than in multiple positions and/or orientations (each of the "2 o'clock position" and "4 o'clock position," etc.). It is not necessary for the patient-matched surface 14 to extend continuously over the base portion 12. Rather, only select portions of the base portion 12 may comprise the patient-matched surface 14. If desired, the patient-matched surface 14 may be textured to improve the overall stability of the patient-matched device 10 with respect to the patient's acetabulum. For example, the texturing may comprise serration, points, cross-hatch, grooves, ridges, bumps, or barbs that increase the friction between the patient's anatomy and the patient-matched surface 14.

[0021] FIGS. 2A and B illustrate an embodiment of an alignment base 30. The alignment base 30 may include a body 32, a first prong 34, and a second prong 36. As described in more detail below, the first and second prongs 34, 36 define a recess 35 that can selectively couple with keyed portions of the patient-matched device 10, the reamer 60 (discussed below), or the impactor 92 (discussed below). The recess 35 is shown with planar sides, but other geometries are also within the scope of other embodiments. FIG. 3 illustrates an embodiment of an alignment platform 50. In certain embodiments, the alignment platform 50 includes at least one alignment indicator 52 that indicates the alignment or orientation of the alignment platform 50. In one non-limiting embodiment, the alignment indicator 52 may comprise a bubble level (which may include a bubble 53 that is measured against a scale). FIG. 3 shows both tubular and bulls-eye types of bubble levels. Other levels or other mechanical, electronic, or other types of devices for indicating the degree of inclination in one or more planes or axes may also be used. For example, other embodiments for the alignment indicator 52 may include an emitter (such as a laser or other light source) that emits a beam of energy (such as a laser or a beam of light) to project on certain landmarks within the surgical environment. It should be understood that the alignment platform 50 is not necessary in all embodiments. For example, in certain embodiments the alignment base may have alignment indicators 52 such that a separate alignment platform 50 is not necessary.

[0022] The alignment platform 50 may be coupled to the alignment base 30. In one non- limiting embodiment, the alignment base 30 comprises a socket 38 that receives a ball 54 associated with the alignment platform 50. To secure the ball 54 within the socket 38 (and thus, to couple the alignment platform 50 to the alignment base 30), a securing member 42 may be advanced within an aperture 40 (for example, by turning or pushing knob 44) until the securing member 42 presses against the ball 54. Other structure and methods for securing the alignment platform 50 to the alignment base 30 would be known to one of skill in the art. For example, in certain embodiments the alignment platform 50 may be formed integrally with the alignment base 30.

[0023] The alignment base 30 may be coupled to the patient-matched device 10, either before or after the alignment platform 50 is coupled to the alignment base 30. Specifically, a keyed portion 18 of the patient-matched device 10 is received within the recess 35 defined by the first and second prongs 34, 36 of the alignment base 30. If desired, a fastener or other means (not shown in the figures) may be used to secure the alignment base 30 to the alignment post 16 such that the two components do not move with respect to each other. It may be desirable to minimize any relative movement of the alignment base 30 and the alignment post 16 in order to ensure that the proper orientation of the surgical instruments is maintained throughout the surgery. Although the sides of the recess 35 and the keyed portion 18 are both shown as planar, any other geometry is possible, provided that the alignment base 30 is secured and does not move with respect to the alignment post 16.

[0024] FIG. 4A and B both illustrate the patient-matched device 10 inserted within a patient's acetabulum 152 of a hip 150. FIG. 4A shows the alignment base 30 and an alignment platform 50 approaching the patient-matched device, whereas FIG. 4B illustrates the alignment base 30 and the alignment platform 50 coupled to the patient-matched device 10. The patient matched device, an indicator, and the alignment base form a surgical instrument for use in hip arthroplasty. In some embodiment, the surgical instrument also includes the alignment platform.

[0025] Various method steps may be performed to create embodiments of the patient- matched surface 14 described herein (such as steps 202-206 in the method 200 schematically illustrated in FIG. 10). The method 200 is generally configured for instruments and/or implants that are used in procedures on a patient' s acetabulum; however, it should be understood that the method 200 may be applied for use in instruments and/or implants on other portions of the anatomy. For instance, patient-matched features and manufacturing methods thereof may be used with instruments configured for contacting portions of a femoral head, glenoid, humerus, radius, ulna, fibula, tibia, proximal femur, foot, ankle, wrist, extremity, or other bony or cartilaginous regions.

[0026] In one embodiment of a method 200 as shown in FIG. 10, there is a step 202 of acquiring imaging data about the geometry or other aspects of the specific patient's anatomy (e.g., data about the bone and/or cartilage surfaces of interest, or data sufficient to determine relevant anatomic and/or mechanical axes, etc). The imaging data may be obtained with magnetic resonance imaging, x-ray (including digital x-rays), ultrasound, computed tomography (CT), or other techniques. For ease of reference, this disclosure refers generally to "imaging data," although it should be understood that in other embodiments, non-image based technologies could be used to obtain sufficient data about the anatomy of interest. In some embodiments, the imaging data does not relate to the entire portion of the anatomy of interest (e.g., the entire acetabulum), but instead, only relates to certain key or desired anatomical points or areas (e.g., the medial portion of the acetabulum).

[0027] Next, as shown in step 204 of method 200, the imaging data may be processed to define the patient-matched device 10. Step 204 may be comprised of multiple sub-steps. For example, step 204 may include processing the imaging data to create a three-dimensional model of the patient's anatomy, and identifying desired position(s) and/or orientation(s) of instruments and/or implants with respect to the patient's anatomy. This step may also include designating alignment axes, cutting planes, or other constructs or references. In some embodiments, the patient-matched device 10 is automatically or semi-automatically defined based on the three- dimensional model, the designated reference data, and other inputs, such as a "blank" from which the patient-matched device is defined.

[0028] In some embodiments, one or more of the above described steps could be performed using computer equipment, whether stand alone or networked. Such computer equipment, in some embodiments, could include memory, a processor, and input / output features, which may facilitate performing at least some of the above identified steps, including creating one or more models. One or more of the above described steps could be performed using a computer assisted design (CAD) software package or another types of design software package.

[0029] Next, as shown in step 206, the method may include creating or manufacturing the patient-matched device 10. Several methods or technologies could be used to manufacture the device 10, including, without limitation, rapid production technologies such as three- dimensional printing or selective laser sintering, molding processes, or other technologies.

[0030] Reference is now made to the method 200 schematically illustrated in FIG. 10. In step 208, the surgeon may orient the patient-matched device 10 within the acetabulum 152 such that the patient-matched surface 14 is fully seated in and substantially conforming to the patient's acetabulm 152. As discussed above, the patient-matched surface(s) 14 will facilitate placing the device 10 at only a single position and/or orientation with respect to the patient's anatomy. When the base 30 is coupled to the patient-matched device 10 as shown in FIG. 4B, the base 30 is substantially locked in place, such that the alignment base 30 does not move with respect to the patient- matched device 10.

[0031] Next, as shown in step 210 of the method 200, the alignment platform 50 may be used to (1) confirm, register, or record a desired position and/or orientation of the patient- matched device 10 with respect to the patient's anatomy. For instance, the alignment platform 50 may be used to confirm, register or record the inclination and anteversion of the axis A2 with respect to the patient's acetabulum. In the embodiment shown in Figure 4B, axis A2 is the same axis defined by the axis Al of the patient-matched device 10, however, in other embodiments, the alignment platform 50 could be used to confirm, register or record angular alignments other than the axis Al defined by the patient-matched device 10. In some embodiments, axis A2 may be non-parallel to axis Al.

[0032] Thus, the alignment platform 50 and indicators 52 may be used to confirm the orientation of the patient-matched device 10 (at the axis A2) for reference in subsequent steps of the surgical procedure. When the alignment base and platform 30, 50 are coupled to one another, the platform 50 does not move with respect to the alignment base 30, such that the alignment indicators 52 will reflect the position and/or orientation of the patient-matched device 10 at axis A2. Thus, in certain embodiments, the surgeon may simply couple the alignment base and platform 30, 50, and mentally note or otherwise record (at least temporarily) the relative positions of one or more of the alignment indicators 52. In other embodiments, the surgeon may adjust the alignment platform 50 with respect to the base 30 such that the alignment indicators 52 reflect a measurement that is easy to remember. (Manipulating the alignment platform 50 should not disturb the orientation of the patient- matched device 10 with respect to the acetabulum 152 (axis A2).) For instance, the alignment platform 50 may be adjusted such that the bubble in the bulls-eye level is aligned with the cross on the center of the bubble level's transparent housing, and/or such that one or both of the bubbles in the tubular levels are aligned at neutral positions along the scales. In other embodiments where the alignment indicators 52 are some type of energy emitter, such as a laser, the surgeon may adjust the platform 50 to aim the laser beam at a particular location within the surgical environment. Then the surgeon may secure the platform 50 to the alignment base 30 with the securing member 42, 44. In subsequent steps of surgical methods described herein, after the patient-matched device 10 is removed, the surgeon can refer back to the alignment indicators 52 to ensure that the surgical instruments and/or implants are properly oriented at axis A2.

[0033] As shown in step 212 of the method 200, the surgeon may insert a reamer 60 into the patient's acetabulum 152. (It should be understood that this step is not always necessary, for example, if the acetabulum 152 is already adequately shaped to receive the acetabular cup 90.) One embodiment of a reamer 60 is shown in FIG. 5, and comprises a reamer portion 62 and asperities 64 that are used to cut or ream the acetabulum 152. The reamer 60 may also comprise a rod 66 that attaches to a handle 68 as shown in FIG. 6. The handle 68 may comprise a rod- receiving portion 70 and grasping portion 78, and may further comprise an alignment post 72 that includes a keyed portion 74 and a tip 76. The alignment post 72, keyed portion 74, and tip 76 of the handle 68 of the reamer 60 may be sized similarly to those of the patient-matched device 10.

[0034] As shown in FIG. 7, the reamer 60 is inserted into the acetabulum 152 and the handle 86 is coupled to the rod 66 of the reamer 60. The alignment base 30 may be coupled to the alignment post 72 of the handle 68. Specifically, keyed portion 74 of the handle 68 is received within the recess 35 of the alignment base 30. If desired, a fastener or other means (not shown in FIG. 7) may be used to secure the alignment base 30 to the alignment post 72 such that the two components do not move with respect to each other. Next, as shown in step 214 of the method 200, the alignment indicators 52 of the alignment platform 50 are used to confirm that the reamer 60 is oriented in the acetabulum 152 correctly. The surgeon may manipulate the orientation of the reamer 60 within the acetabulum 152 until one or more of the alignment indicators 52 indicate the same orientation (the axis A2) that was previously noted with respect to the patient-matched device 10. Next, as shown in step 216 of the method 200, the surgeon may ream the acetabulum, making sure to maintain the orientation of the reamer 60 at the axis A2 (as confirmed by the alignment indicators 52). Then the surgeon may remove the reamer 60 from the acetabulum 152, and may de-couple the alignment base 30 from the alignment post 72 of the handle 68.

[0035] Next, as shown in step 218 of the method 200, the surgeon may insert an acetabular cup 90 within the acetabulum 152, and further, may use an impactor 92 to impact the cup 90. FIG. 8 shows an acetabular cup 90 and one embodiment of an impactor 92. The impactor 92 may comprise an impacting portion 94 that is inserted into the cup 90, and may further comprise a handle 96, an alignment post 98, a keyed portion 100, and a tip 102. The alignment post 98, keyed portion 100, and tip 102 of the impactor 92 may be sized similarly to those of the patient-matched device 10.

[0036] As shown in FIG. 9, the acetabular cup 90 and the impactor 92 are both inserted into the acetabulum 152, and the alignment base 30 is coupled to the alignment post 98 of the impactor 92. Specifically, keyed portion 100 of the impactor 92 is received within the recess 35 of the alignment base 30. If desired, a fastener or other means (not shown in FIG. 9) may be used to secure the alignment base 30 to the alignment post 98 such that the two components do not move with respect to each other. Next, as shown in step 220 of the method 200, the alignment indicators 52 of the alignment platform 50 are used to confirm the orientation of the impactor 92 (and the cup 90). The surgeon may manipulate the orientation of the impactor 92 (and the cup 90) within the acetabulum 152 until the alignment indicators 52 indicate the same orientation (axis A2) that was previously noted with respect to the patient- matched device 10. Next, as shown in step 222 of the method 200, the surgeon may impact the acetabular cup 90, making sure to maintain the proper orientation of the impactor 92 (and the cup 90) as confirmed by the alignment indicators 52.

[0037] Thus, embodiments of devices and methods described herein allow the surgeon to maintain the proper orientation of surgical instruments and/or implants throughout a surgery. In certain embodiments, the patient- matched device 10 may include a patient-matched surface 14 and an alignment post 16 that is oriented at axis Al, both of which may be pre-operatively determined such that a proper orientation is determined for the instruments and/or implant. An alignment base and platform 30, 50 may selectively couple to the alignment posts of the patient- matched device 10, the reamer 60, and the impactor 92. The surgeon may use alignment indicators 52 on the alignment platform 50 to ensure that the proper orientation for all the instruments is maintained throughout the surgery. While for convenience, the devices and methods shown and described are generally shown as configured for use in procedures on a patient's acetabulum, it is anticipated that the same principals may be applied to surgical instruments and implants configured for use in other procedures.

[0038] While the above-embodiments described a mechanical level (either bubble or linear) that measures 3D position relative to a static gravitational vector, those of ordinary skill in the art would understand that the static tilt also could be measured electronically. For example, any device that contains a 3-axis accelerometer, which is common in many consumer electronic devices (such as iPhone, iPad, some laptop computers, etc.), could be used to measure, store, and compare a tilt of the device relative to the static gravitational vector. The marks "iPhone" and "iPad" are registered trademarks of Apple, Inc. of 1 Infinite Loop, Cupertino, California. Alternatively, components could be purchased and assembled into a custom built assembly to measure, store, and compare a tilt of the device relative to the static gravitational vector. In yet another embodiment, a hybrid approach may be taken by combing a portable consumer electronic device with a 3-axis accelerometer on a USB stick. Therefore, a variety of electronic solutions that utilize a 3-axis accelerometer (either off the shelf, such as an iPhone where all that is needed is to develop the software application, or a custom built assembly).

[0039] As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above- described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.

Claims

CLAIMS What is claimed is:

1. A surgical instrument for use in hip arthroplasty, the surgical instrument comprising: a. a patient matched device having a base portion and an alignment post, the base portion having a patient matched surface;

b. an alignment base removably attached to the patient matched device; and c. at least one alignment indicator operatively connected to the alignment base.

2. The surgical instrument of claim 1, wherein the at least one alignment indicator is integral with the alignment base.

3. The surgical instrument of claim 1, wherein the alignment post comprises a keyed portion and a tip.

4. The surgical instrument of claim 1, wherein the alignment post extends along an axis that reflects a pre-operatively determined desired orientation.

5. The surgical instrument of claim 1, wherein the alignment post and the base portion are monolithic.

6. The surgical instrument of claim 1, wherein the base portion is hollow.

7. The surgical instrument of claim 1, wherein only select areas of the base portion comprise the patient matched surface.

8. The surgical instrument of claim 1, wherein at least a portion of the patient matched surface is textured.

9. The surgical instrument of claim 1, wherein the at least one indicator comprises a bubble level.

10. The surgical instrument of claim 1, wherein the at least one indicator comprises a 3-axis electronic accelerometer.

11. The surgical instrument of claim 1, wherein the at least one indicator comprises an emitter.

12. The surgical instrument of claim 1, wherein the alignment base comprises a body, a first prong, and a second prong.

13. The surgical instrument of claim 12, where the first prong and the second prong define a recess.

14. The surgical instrument of claim 1, further comprising an alignment platform removably attached to the alignment base, and the at least one indicator is integral with the alignment platform.

15. The surgical instrument of claim 14, wherein the alignment base comprises a socket that receives a ball associated with the alignment platform.