Bone screw implants for sacroiliac joint fusion

Abstract

A bone screw for sacroiliac joint fusion is characterized by a longitudinal bone screw and a cylindrical sleeve housed on the proximal end of the bone screw. The sleeve has axially extending fins or grooves on its outer surface, the fins or grooves extending generally from one end of the sleeve to the other end of the sleeve. This feature enables the sleeve to resist reverse rotation, thereby helping to prevent the bone screw from backing out once installed. The bone screw has a self-tapping tip that allows the bone screw to be installed without the need for a guide hole, and has a self-collecting geometry that collects and retains bone chips generated by the installation of the bone screw in and along the bone screw for use as a graft for bone fusion.

Description

Technical Field

[0001] The present invention relates to bone screws for use in the spine and related anatomical structures, and more particularly, to bone screws for use in sacroiliac joint fusions and related anatomical structures. Background Art

[0002] Bone screws are commonly used for repair, stabilization, fixation, fusion, and other bone procedures in the human skeleton, such as the spine and pelvis. However, wherever bone screws are used, they face the challenge of "backing out" of the anatomical structure in which they are installed. Bone screw failures such as backing out can compromise the integrity of the bone subject in which the bone screw is installed and / or present serious risks and / or complications to the implant recipient.

[0003] In view of the above, it would therefore be desirable to have a bone screw that minimizes or eliminates back-out. SUMMARY OF THE INVENTION

[0005] A bone screw implant for sacroiliac joint fusion includes a bone screw and a separate linear sleeve configured to resist reverse rotation of the bone screw once installed to help prevent screw back-out, the bone screw having a self-drilling tip geometry that enables the bone screw to be installed without the need for a pilot hole, and a self-harvesting geometry that gathers and retains bone shavings generated by the installation of the bone screw in the bone screw to serve as a graft for bone fusion.

[0006] The sleeve has a non-radial (axial) geometry on its outer surface that helps resist rotational forces applied to the implant when fully secured in the bone (in situ). The anti-rotation geometry linearly press fits into the bone anatomy surrounding the bone screw to secure its rotational position. In one form, the anti-rotation geometry includes tapered fins. In another form, the anti-rotation geometry includes tapered grooves. In yet another form, the anti-rotation geometry includes non-tapered grooves. Other geometries are contemplated.

[0007] The sleeve also has a geometry that provides for permanent assembly to the bone screw and binds / attaches itself to / at a specific axial position on the bone screw to help prevent backing out of the bone screw. In one form, the sleeve has an inner radial groove within its inner diameter that engages a circumferential protrusion (e.g., a ring) on ​​the bone screw that allows the sleeve to be captured by the bone screw while also allowing the sleeve to rotate freely relative to the bone screw.

[0008] The free-rotating sleeve allows the sleeve to be linearly press-fitted into the bone while the bone screw is threaded into the bone until both components are fully seated in the bone. To withdraw the bone screw from the bone, the threads will have to be rotated loose while also overcoming the shear forces created by the press-fit condition / connection of the sleeve to the end of the bone screw.

[0009] The bone screw may include an external thread on its proximal end for engaging with a screwdriver. The proximal thread provides a secure connection interface with the screwdriver so that the bone screw will not accidentally come off the screwdriver when the bone screw is installed in the bone.

[0010] The sleeve may additionally include threads on its inner surface near the proximal end of the sleeve that engage with external threads on the proximal end of the bone screw. Once the bone screw has been fully secured in the bone, the combination of these thread forms on the two components is connected together with a set screw to form a second mechanism that locks the two components together. The set screw will further prevent the bone screw from backing out and will linearly "push" the sleeve out of the bone.

[0011] The tip geometry of a self-drilling bone screw is characterized by multiple cutting tips or blades located around a central opening. This geometry allows the surgeon to eliminate surgical steps, thereby shortening the surgical procedure.

[0012] The self-collecting geometry is characterized by spiral cutting flutes and windows located at various intervals within the spiral flute geometry that collect bone / bone cuttings (autograft) during insertion of the bone screw into the bony anatomy.

[0013] In particular, when the bone screw is rotated into the bone anatomy, the spiral cutting groove gathers and deposits bone debris into the window. In one form, the window includes a circular and / or oval hole. In another form, the window includes a groove. In all cases, the window can be perpendicular to the long axis of the bone screw, angled relative to the long axis of the bone screw, formed in a spiral pattern relative to the spiral trajectory of the spiral cutting groove, and / or a combination thereof. This feature solves the current challenge of pre-packing the bone screw / implant with a biological graft before implantation, or inserting the biological graft into the bone screw / implant through the axial sleeve of the bone screw after final implantation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The features of the present invention will be better understood by reference to the accompanying drawings, in which:

[0015] Figure 1 is an isometric view of a bone screw implant made in accordance with the principles of the present invention;

[0016] Figure 2 yes Figure 1 Exploded isometric view of a bone screw implant;

[0017] Figure 3 yes Figure 1 An exploded side view of a bone screw implant;

[0018] Figure 4 yes Figure 1 An exploded side cross-sectional view of a bone screw implant;

[0019] Figure 5 yes Figure 1 Another isometric view of a bone screw implant;

[0020] Figure 6 yes Figure 1 Isometric cross-sectional view of a bone screw implant;

[0021] Figure 7 yes Figure 1 An enlarged cross-sectional view of the proximal end of a bone screw and a sleeve of a bone screw implant;

[0022] Figure 8 yes Figure 1 A side view of a sleeve of a bone screw implant;

[0023] Fig. 9 yes Figure 1 An end view of a sleeve of a bone screw implant;

[0024] Fig.10 yes Figure 1 An isometric view of a sleeve of a bone screw implant;

[0025] Fig.11 yes Figure 1 an enlarged view of a proximal end of a bone screw of a bone screw implant;

[0026] Fig.12 is used for Figure 1 An isometric view of an alternative sleeve for a bone screw implant;

[0027] Fig.13 yes Fig.12 An end view of an alternative sleeve;

[0028] Fig.14 yes Fig.12 A side view of an alternative sleeve;

[0029] Fig.15 yes Figure 1 An isometric view of a bone screw of a bone screw implant;

[0030] Fig.16 yes Figure 1 An enlarged view of the distal end (tip) of a bone screw of a bone screw implant;

[0031] Fig.17 yes Figure 1 an end view of a distal end of a bone screw of a bone screw implant;

[0032] Fig.18 yes Figure 1 An enlarged isometric view of a bone screw of a bone screw implant;

[0033] Fig.19 yes Figure 1 An enlarged end view of the distal end (tip) of a bone screw of a bone screw implant;

[0034] Fig. 20 yes Figure 1 An enlarged side view of a bone screw of a bone screw implant;

[0035] Fig.21 is an isometric view of another bone screw implant made according to the present principles;

[0036] Fig. 22 yes Fig.21 An enlarged view of the proximal end of a bone screw implant;

[0037] Fig.23 yes Fig.21 A cross-sectional view of the bone screw implant taken along line 23-23 thereof;

[0038] Fig.24 yes Fig. 22 A cross-sectional view of the proximal end of the bone screw implant taken along line 24-24 thereof;

[0039] Fig.25 yes Fig.21 Another cross-sectional view of a bone screw implant;

[0040] Fig.26 yes Fig.21 Another cross-sectional view of the proximal end of the bone screw implant;

[0041] Fig. 27 yes Fig.21 A cross-sectional view of the proximal end of a bone screw implant without a fixation screw;

[0042] Fig.28 yes Fig.21 A cross-sectional view of a proximal end of a bone screw implant, wherein the fixation screw is shown exploded therefrom;

[0043] Fig.29 yes Fig.21 another cross-sectional view of the proximal end of the bone screw implant, wherein the fixation screw is shown exploded therefrom;

[0044] Fig.30 yes Fig.21 An enlarged view of the proximal end of a bone screw implant showing the fixation screw exploded therefrom.

[0045] Detailed Description of the Invention

[0046] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will be understood, however, that no limitation of the scope of the database is intended thereby.

[0047] Figure 1-7 Various exploded and non-exploded views of a bone screw implant 10 made in accordance with the present principles are shown featuring a bone screw 12 and a sleeve 14 . Fig.11 and 15 -20 shows various views of the bone screw 12. Figure 8-10 Various views of the sleeve 14 are shown, and Figure 12-14 Various views of an alternative sleeve 14a are shown.The bone screw implant 10 is best suited for use in sacroiliac fusions, but may be used in a variety of spinal applications as well as other orthopedic applications.

[0048] The bone screw 12 is characterized in that the body 30 has a self-drilling or self-tapping tip 44 at its distal end and may include external threads 37 adjacent the proximal end 41 of the body 30 and particularly located near the upper portion of the unthreaded tubular terminal portion 32. The body 30 defines a longitudinal or major axis and length between the tip 44 and the terminal 41 and includes external threads / threads 33 on its outer surface that generally extend from the tip / distal end 44 to the terminal portion 32. The inner sleeve 34 preferably, but not necessarily, extends the entire longitudinal length of the body 30 and intersects with a socket 38 in the upper cylindrical portion 32 of the body 30, thereby providing communication between the tip 44 and the socket 38. The socket 38 is configured to receive a similarly constructed tool (not shown) for use in implanting the bone screw implant 10. The outer surface of the upper portion 32 of the body 30 has a ridge, protrusion, annulus, ring or the like (collectively referred to as a "ring") 36 that extends around the circumference of the upper portion 32, near the neck 39 between the upper portion 32 and the outer threads 33 of the body. As shown, the ring 36 can be continuous (conformal), or can be discontinuous (non-conformal), such as formed by multiple ring portions (not shown). The ring 36 engages the inner radial groove 23 in the inner diameter 22 of the sleeve 14 (see, e.g., Figure 7 ), which interaction enables the sleeve 14 to be captured by the bone screw 12.

[0049] The tip 44 of the bone screw 12 (see, e.g. Figure 15-20) is self-drilling and is formed by several (e.g., multiple) cutting blades, heads, or the like 45a, 45b, 45c, it being understood that the tip 44 may include more or fewer cutting points 45. The cutting blades 45a-c are located around the opening of the cannula 34 at the tip 34 and are preferably, but not necessarily, equally radially spaced around the cannula opening. Each blade 45a-c is configured to drill, cut, or otherwise dig into bone.

[0050] The bone screw 12 has a self-collecting geometry that gathers and retains bone chips generated by the bone screw installation to serve as a graft for bone fusion. To this end, the bone screw 12 has several (e.g., multiple) preferably but not necessarily spiral cutting channels, grooves, grooves or the like (collectively referred to as "grooves") 35a, 35b, 35c, which extend through the threads 33 of the bone screw body 30 from the tip 44 to the upper portion 32.

[0051] A spiral cutting groove 35 is associated with a cutting blade 45, such that cutting blade 45a is associated with spiral cutting groove 35a, cutting blade 45b is associated with spiral cutting groove 35b, and cutting blade 45c is associated with spiral cutting groove 35c. Each cutting groove 35 has a plurality of windows, openings, holes or the like (collectively referred to as windows) 40, which are located at different intervals within the spiral groove geometry, and collect bone / bone chips (autograft) together during the insertion of the bone screw into the bone anatomical structure. In particular, when the bone screw 12 is rotated into the bone anatomical structure, the spiral cutting groove 35 causes the bone chips to gather and deposit in the window 40. In one form, the window 40 is a circular and / or elliptical hole. In another form, the window 40 is a groove. In all cases, the window 40 can be perpendicular to the long axis of the bone screw, angled relative to the long axis of the bone screw, formed in a spiral pattern relative to the spiral trajectory of the spiral cutting groove, and / or a combination thereof.

[0052] The sleeve 14 is characterized by a generally cylindrical body 16 defining a front portion 17, an end portion 18, and an interior, bore, or the like 22. The front portion 17 of the body 16 has a taper, angle, or inclination (collectively, "taper") 19 circumferentially around the front portion 17, the taper 19 providing a transition from the body 30 of the bone screw 12 to the sleeve 14 for ease of installation / implantation. The sleeve 14 has an anti-rotation feature that performs the function of resisting rotation of the implant (screw assembly) 10 when fully seated in the bone, the anti-rotation feature comprising three (3) fins or the like 21 on the outside of the body 16, each fin 21 projecting radially outwardly from the outer surface of the body 16 and extending axially along the outer surface of the body. Each fin 21 is preferably, but not necessarily, tapered from its front portion (proximate the front portion 17 of the body 16) to its rear portion (at or near the rear portion 18 of the body 16). The external fins 21 are also preferably, but not necessarily, equally spaced around the outer circumference of the body 16. It should be understood that in all cases, the number of external fins 21 can be greater or less than three (3). The body 16 also has a plurality of slits, slots, channels, or the like (collectively referred to as "slits") 20 around the radial circumference / diameter of the body at the front portion 17 of the body. Each slit 20 extends axially from the front portion 17 along the body 16 a certain distance into the body. The slits 20 allow the front portion of the sleeve 14 to elastically expand (and then contract) so that the ring 36 of the bone screw 12 can be received in the groove 23 of the sleeve 14 in a snap-fit ​​manner.

[0053] The interior of the sleeve 14 has a radial groove, slot, channel, cutout or the like (collectively referred to as a "groove") 23 that preferably, but not necessarily, extends the entire circumference or diameter around or around the inner surface of the hole 22 near the front portion 17. The radial groove 23 is sized to receive the ring 36 of the bone screw 12. In particular, the radial groove 23 of the sleeve 14 receives the ring 36 of the bone screw 12 so that the bone screw 12 captures the sleeve 14 while also allowing the sleeve 14 to rotate freely relative to the bone screw 12. The free-rotating sleeve allows the sleeve to be linearly press-fit into the receiving bone (not shown) while the bone screw is threaded into the receiving bone until both components are fully secured in the receiving bone.

[0054] Figure 12 to Figure 14An alternative sleeve 14a for bone screw 12 / implant 10 is depicted. Sleeve 14a is a variation of sleeve 14. In particular, sleeve 14a has a variation of its anti-rotation feature. However, other features, components, etc. are the same as sleeve 14, and therefore, these same and / or similar features, components, etc. have the same reference numbers as sleeve 14. Sleeve 14a has a plurality of grooves or the like 26 on the outside of body 16, each groove 26 protruding radially outward from the outer surface of body 16 and extending axially along the outer surface of body. Each groove 26 may be tapered or non-tapered from its front (near the front 17 of body 16) to its rear (at or near the rear 18 of body 16). The external grooves 26 are also preferably, but not necessarily, equally spaced around the outer circumference of body 16. It should be understood that in all cases, the number of external grooves 26 may be greater or less than the number shown.

[0055] Figure 21-30 Various views of another bone screw implant 10a made in accordance with the present principles are depicted, featuring a bone screw 12, a sleeve 14b, and a set screw 50 (the sleeve and set screw forming a sleeve assembly). The bone screw implant 10a is identical to the bone screw implant 10, except that a second locking mechanism is incorporated between the bone screw 12 and the sleeve / sleeve assembly 14b. As such, the features, characteristics, properties, and attributes of the bone screw 12 will not be revisited except where necessary and / or appropriate to describe the bone screw assembly 10a, such as, but not limited to, describing the bone screw 12 relative to the sleeve / sleeve assembly 14b.

[0056] The sleeve 14b is the same as the sleeve 14, except that threads 24 are added to the upper inner wall / hole 22 near the end 18. The size of the hole 22 can be slightly larger than the hole 22 of the bone screw implant 10 to form an internal threaded cavity 25 or the size of the inner cavity can be the same. The sleeve assembly includes a set screw 50, which provides secondary locking of the sleeve 14b to the bone screw 12. The set screw 50 has a hexagonal side 51 (or other configurations for engaging with a set screw driver (not shown)). The hole 52 is set in the top 53 of the set screw 50, which allows engagement with an installation / removal tool (not shown). The set screw 50 also has a lower cylindrical wall 54 that defines a cylindrical cavity 57. Threads 55 are provided on the outer side of the annular wall 54. Threads 56 are also provided on the inner side of the annular wall 54.

[0057] Once the sleeve 14b is mounted on the bone screw 12, the fixing screw 50 is installed. The fixing screw 50 is screwed into the annular cavity 25 formed between the outer side of the upper portion 32 of the bone screw 12 and the inner side of the upper portion of the sleeve 14b. In particular, the annular wall 54 of the fixing screw 50 is received in the annular cavity 25. The internal threads 56 of the annular wall 54 of the fixing screw 50 engage the external threads 37 of the bone screw 12, while the external threads 55 of the annular wall 54 of the fixing screw 50 engage the internal threads 24 of the sleeve 14b. This connects the sleeve to the bone screw.

[0058] It should be readily appreciated that the bone screw implant of the present invention is superior to the prior art.

Claims

1. A bone screw implant, comprising: a bone screw defining a longitudinal axis and having external threads, a proximal end having a sleeve engagement geometry, a distal end having a tip with a self-tapping geometry, external threads extending from the distal end to approximately the proximal end, and a self-collecting bone cutting geometry about the longitudinal axis that gathers and retains bone cuttings generated by the bone cutting geometry; The sleeve engagement geometry includes a ridge extending circumferentially about the proximal end and perpendicular to the longitudinal axis, and a cylindrical sleeve having an outer surface, a first end, a second end, a cylindrical bore extending from the first end to the second end and defining an inner surface, an anti-rotation geometry on the outer surface, and a bone screw engagement geometry on the inner surface, the bone screw engagement geometry comprising a groove extending circumferentially around the cylindrical sleeve perpendicular to an axis of the cylindrical bore; wherein the anti-rotation geometry of the sleeve projects outwardly from the outer surface and extends axially along the outer surface, Wherein the ridges of the sleeve engagement geometry are configured to be received within the grooves of the bone screw engagement geometry to allow the cylindrical sleeve to freely rotate relative to the bone screw.

2. The bone screw implant of claim 1, wherein the self-tapping geometry of the tip comprises a plurality of cutting blades arranged around a central hole.

3. The bone screw implant of claim 2, wherein the self-collecting bone cutting geometry comprises a helical cutting groove extending from the tip to adjacent the proximal end, the helical cutting groove being configured to create bone graft during implantation of the bone screw.

4. The bone screw implant of claim 3, further comprising a plurality of windows in the helical cutting groove, each of the plurality of windows being configured to receive and retain bone chips generated by the helical cutting groove during implantation of the bone screw.

5. The bone screw implant of claim 4, wherein the plurality of windows are disposed at different intervals around each spiral cutting groove.

6. The bone screw implant of claim 5, wherein each of the plurality of windows comprises a hole.

7. The bone screw implant of claim 6, wherein each hole is oval.

8. The bone screw implant of claim 5, wherein the plurality of windows comprise slots.

9. The bone screw implant of claim 5, wherein the plurality of windows are perpendicular relative to the longitudinal axis.

10. The bone screw implant of claim 5, wherein the plurality of windows are angled relative to the longitudinal axis.

11. The bone screw implant of claim 1 , wherein the anti-rotation geometry of the sleeve comprises tapered fins.

12. The bone screw implant of claim 1, wherein the anti-rotation geometry of the sleeve comprises a groove.

13. The bone screw implant of claim 12, wherein the recess is tapered.

14. The bone screw implant of claim 1, wherein: The groove is sized to receive the ridge in a press fit manner.

15. The bone screw implant of claim 14, wherein: The groove includes a circumferential channel.

16. The bone screw implant of claim 15, wherein: The sleeve engagement geometry of the proximal end of the bone screw further includes a first radial thread at a distal end of the proximal end; and The bone screw engagement geometry of the sleeve also includes a second radial thread at the distal end of the sleeve.

17. The bone screw implant of claim 16, further comprising a fixing screw having: providing external threads for engagement with said second radial threads; and An internal thread is provided for engagement with the first radial thread.

18. The bone screw implant of claim 14, wherein the cylindrical sleeve further comprises a plurality of grooves positioned around a radial circumference of the cylindrical sleeve and configured to allow elastic expansion of the cylindrical sleeve when the circumferential protrusions of the bone screw engage the radial grooves of the cylindrical sleeve.

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