Receiving part of a bone anchoring device and system of at least one instrument and a receiving part

Abstract

To provide a receiving part for coupling a bone anchoring element to a stabilization element such as a rod.SOLUTION: A receiving part (5) for a bone-anchoring device includes a first end 5a, a second end 5b opposite to the first end, a central shaft extending through the first end and the second end, and a substantially U-shaped recess for receiving a rod (10) adjacent to the first end, the substantially U-shaped recess forming two free legs 55a, 55b. A circumferential groove 57a, 57b is provided in the outer surface 56 of at least one of the legs, which groove is delimited in the direction of the central axes by an upper surface and a lower surface, and a recess 58b is provided in the outer surface of at least one leg, which recess is delimited in the direction of the central axes by an upper surface and a lower surface. At the outer surface of the receiving part, the lower surface of the recess and the lower surface of the groove are provided at substantially the same distance from the first end of the receiving part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a receiving element that may be part of a coupling device for connecting a bone anchor element to a stabilizing element, such as a rod. In particular, the receiving element may be equally configured to engage a first instrument and a second instrument different from the first instrument, particularly for use in spinal surgery. The present invention further relates to a coupling device having such a receiving element, as well as a system of at least one instrument and a receiving element. [Background technology]

[0002] A receiving part of a bone anchor device is known from US 2016 / 0361093, which receiving part includes a substantially U-shaped recess forming two free legs, wherein a groove is provided on the outer surface of each of the legs, and in a plane including the central axis of the receiving part and extending through the center of each leg, the contour of the surface of the groove has at least a first arcuate portion and a second arcuate portion opposite the first arcuate portion, and the contour is substantially free of straight lines.

[0003] Various other receiving parts with engagement structures for instruments are known, for example from WO 2018 / 191131 or WO 2023 / 022886. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide an improved receiving part for a bone anchor device and a coupling device comprising a receiving part that particularly facilitates and / or supports engagement of the receiving part with an instrument, and at least two different instruments can be selectively interchangeably used with the receiving part. It is also an object to provide a system of such a receiving part and at least one instrument. [Means for solving the problem]

[0005] This object is solved by a receiving part according to claim 1, by a connecting device according to claim 14 and by a system of at least one tool and receiving part according to claim 15. Further developments are described in the dependent claims.

[0006] According to one embodiment, a bone anchor device includes a receiving part extending along a central axis from a first end to a second end, and a substantially U-shaped recess adjacent the first end for receiving a rod, the substantially U-shaped recess forming two free legs of the receiving part. The receiving part includes a circumferential groove on an outer surface of at least one of the legs, the groove being defined in the direction of the central axis by upper and lower surfaces, and a recess on the outer surface of at least one of the legs, the recess being defined in the direction of the central axis by upper and lower surfaces. The lower surface of the recess and the lower surface of the groove are located at substantially the same distance from the first end of the receiving part on the outer surface of the receiving part.

[0007] The grooves and / or recesses can aid in the engagement of the instrument with the receiving part, with the upper and lower surfaces of the grooves and recesses allowing for a secure attachment of the instrument to the receiving part, in particular allowing for the transmission of forces from the instrument to the receiving part, while preventing unintentional removal of the instrument from the receiving part.

[0008] By providing the lower surfaces of both the recess and the groove at the same axial height of the receiving part on its outer surface, it is possible to reproducibly position an instrument mounted on the receiving part, even when different instruments are used. Furthermore, by providing both lower surfaces at the same axial height on the outer surface, it is ensured that when an instrument that engages only one of the groove and the recess is used, the coupling process of mounting the instrument on the receiving part is not obstructed by the other of the groove and the recess.

[0009] The receiving piece can be manufactured in a simple and cost-effective manner. Furthermore, the receiving piece can be used with a variety of instruments having different engagement structures for engaging the receiving piece. Specifically, a first instrument can be configured to engage with a groove in the receiving piece, and a second instrument can be configured to engage with a recess in the receiving piece. The first instrument can be configured to engage only with the groove and not the recess, and the second instrument can be configured to engage only with the recess and not the groove.

[0010] Therefore, the receiving part can be combined with different types of existing instruments, increasing the versatility of the receiving part, thereby reducing the cost of inventory required for surgery.

[0011] The bone anchor device, including the receiving part and the bone anchor element, may be configured in any suitable form. For example, the bone anchor device may be a polyaxial bone anchor device, a uniplanar bone anchor device, or a uniaxial bone anchor device. The bone anchor device may be a bottom-loading type, in which the head of the bone anchor device is insertable into the receiving part from the bottom end, or a top-loading type, in which the head is insertable into the receiving part from the top end.

[0012] According to a further embodiment, a coupling device is provided for coupling a bone anchor element to a rod, the bone anchor element comprising a shank for fixation in bone and the coupling device comprising a receiving part according to the above-mentioned embodiments. Preferably, the bone anchor element comprises a head, the receiving part being configured to receive the head of the bone anchor element, and further preferably, the coupling device comprises a locking device configured to cooperate with the receiving part to lock the head to the receiving part.

[0013] According to a further embodiment, there is provided a system of at least one of the instruments and receiving piece of the above-mentioned embodiments, wherein the instrument comprises a tubular portion having two arms, at least one arm comprising on its inner surface at least one protrusion configured to engage in a groove and / or recess in the receiving piece. Preferably, the instrument is a first instrument, and the at least one protrusion is formed as a circumferentially extending rib configured to engage in the groove in the receiving piece, and / or the instrument is a second instrument, and the at least one protrusion is formed on a circumferentially intermediate portion of the arm of the second instrument and configured to engage in a recess in the receiving piece.

[0014] The receiving component, coupling device, and system can each be used in particular spinal surgery, and more particularly in minimally invasive surgery (MIS).

[0015] Further features and advantages of the present invention will become apparent from the description of the embodiments taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view of a bone anchor device with a receiving piece according to one embodiment. [Figure 2] FIG. 2 is a perspective view of the receiving part of FIG. 1; [Figure 3] 3 is a perspective view from a little above of the receiving part shown in FIGS. 1 and 2; FIG. [Figure 4] FIG. 4 is a perspective view of the receiving part shown in FIGS. 1 to 3, taken from slightly below. [Figure 5] FIG. 5 is an enlarged view of a portion of the receiving part shown in FIG. 4 . [Figure 6] FIG. 4 is an enlarged view of a portion of the receiving part shown in FIG. 3 . [Figure 7] 4 is an enlarged view of another portion of the receiving part shown in FIG. 3. [Figure 8] FIG. 8 is a side view of the receiving part shown in FIGS. [Figure 9] FIG. 8 is another side view of the receiving part shown in FIGS. [Figure 10]9 , taken along line AA of FIG. 9 , is an enlarged cross-sectional view of a detail of the receiving piece shown in FIG. 9 . [Figure 11] 10 is an enlarged cross-sectional view of a detail of the receiving piece shown in FIG. 9, taken along line BB in FIG. [Figure 12] 1 is a perspective view of a portion of an apparatus according to a first embodiment; [Figure 13] 13 is a perspective view of the bone anchor device of FIG. 1 with a portion of the instrument of FIG. 12 attached thereto. [Figure 14] 14 is a cross-sectional view of the bone anchor device having a portion of the instrument shown in FIG. 13, taken along a plane perpendicular to the rod axis of the inserted rod. [Figure 15] FIG. 10 is a perspective view of a portion of an apparatus according to a second embodiment. [Figure 16] 16 is a perspective view of the bone anchor device of FIG. 1 with a portion of the instrument of FIG. 15 attached thereto. [Figure 17] 17 is a cross-sectional view of the bone anchor device having a portion of the instrument shown in FIG. 16, taken along a plane perpendicular to the rod axis of the inserted rod. [Figure 18] FIG. 10 is a side view of an example of another receiving part. [Figure 19] FIG. 10 is a side view of an example of yet another receiving part. DETAILED DESCRIPTION OF THE INVENTION

[0017] As shown in FIG. 1 , and with reference to FIGS. 14 and 17 , a bone anchor device according to one embodiment includes a bone anchor element 1 having a threaded shank 2 and a head 3 having a spherical outer surface portion. The bone anchor device further includes a receiving part 5 for connecting the head 3 of the bone anchor element 1 to a spinal fixation element, such as a rod 10. A pressure element 6 is at least partially disposed within the receiving part 5 and configured to apply pressure to the inserted head 3 to secure the head 3 within the receiving part 5. A fixation member, such as a set screw 7, is provided for securing the rod 10 to the receiving part 5. The pressure element 6 and head 3 are shown in FIGS. 14 and 17 .

[0018] The receiving part 5 is shown in more detail in Figures 2-11. The receiving part 5 may be a monolithic part. Typically, the receiving part 5 may be formed as a substantially cylindrical section having a first or top end 5a, a second or bottom end 5b, and a central axis C extending through the top and bottom ends 5a and 5b. A passage 51 extends along the central axis C from the top end 5a to the bottom end 5b. Near the bottom end 5b of the receiving part 5, a narrowed portion 52 of the passage 51 provides a seat for the head 3 of the anchor element 1. The bottom end 5b of the receiving part 5 defines a lower opening 53 through which the shank 2 can pass. The receiving part 5 further includes a substantially U-shaped recess 54 extending from the top end 5a to the bottom end 5b. The U-shaped recess 54 serves to receive the rod 10 therein. Two free legs 55a, 55b of the receiving part 5 are defined by the U-shaped recess 54. The upper part of the legs 55a, 55b may be provided with an internal thread 55c for cooperating with a set screw 7 for fixing the rod 10. The receiving part 5 may have a rounded edge at its top end 5a.

[0019] The outer surface 56 of each leg 55a, 55b defines a circumferential groove 57a, 57b and a recess 58a, 58b, respectively. The circumferential groove 57a, 57b and / or the recess 58a, 58b may function as an engagement portion for engaging an instrument with the receiving part 5, as described in more detail below. More generally, the recesses 58a, 58b each define a notch that intersects with the corresponding groove 57a, 57b.

[0020] The circumferential grooves 57a, 57b and the recesses 58a, 58b each extend from the outer surface 56 of the receiving part 5 toward the central axis C. Thus, the radial thickness of the legs 55a, 55b may be reduced by the grooves 57a, 57b and the recesses 58a, 58b. In each of the legs 55a, 55b, the circumferential grooves 57a, 57b and the recesses 58a, 58b, respectively, intersect at the circumferential center of the leg.

[0021] The circumferential grooves 57a, 57b of each leg 55a, 55b are provided away from the top end 5a of the receiving part 5. Furthermore, the circumferential grooves 57a, 57b extend from one end of the channel formed by the U-shaped recess 54 to the other end of the channel and open towards the U-shaped recess 54. In other words, the circumferential grooves 57a, 57b extend in an arc shape along the entire circumferential extension of the respective leg 55a, 55b in the circumferential direction of the receiving part 5, i.e., in a plane perpendicular to the central axis C.

[0022] Each of the circumferential grooves 57a, 57b is defined toward the top end 5a of the receiving piece 5 by a groove upper surface 571 and toward the bottom end 5b by a groove lower surface 572. As best shown in FIG. 9 , on the outer surface 56 of the receiving piece 5, the lower surfaces 572 of the grooves 57a, 57b are located a first distance d1 from the top end 5a of the receiving piece 5, and the upper surfaces 571 are located a second distance d2 from the top end 5a of the receiving piece 5, the second distance d2 being less than the first distance d1.

[0023] The upper and lower surfaces 571, 572 of the grooves 57a, 57b may be sloped from the outer surface 56 of the receiving piece toward the top end 5a. In this embodiment, the upper and lower surfaces 571, 572 are generally planar and extend from the outer surface 56 deep into the receiving piece 5. Side walls 573 or bottoms of the grooves 57a, 57b define the grooves deep. The side walls 573 may be planar or may be connected to the upper and lower surfaces 571, 572 by rounded edges.

[0024] It should be understood that the upper and lower surfaces 571, 572 and the sidewall 573 are not limited to being flat. Rather, they may have any other shape, such as a rounded or arcuate shape. Depending on the shape of the upper and lower surfaces 571, 572, the sidewall 573 may be omitted.

[0025] Grooves 57a, 57b have a depth t1 extending from the outer surface 56 of receiving piece 5 to the point of the groove that extends inward most into the receiving piece. In this embodiment, grooves 57a, 57b have a depth t1 between outer surface 56 and side wall 573, as shown in Figures 10 and 11.

[0026] The recesses 58a, 58b of each leg 55a, 55b are located midway along the circumferential direction of the respective leg. In the axial direction, the recesses 58a, 58b are located away from the top end 58a of the receiving piece. As can be seen particularly in Figures 4 to 6, in the circumferential direction of each leg 55a, 55b, the recesses 58a, 58b extend from the first end 580a of the recess to the second end 580b. The width of the recesses 58a, 58b between the first end 580a and the second end 580b is smaller than the circumferential extension of the grooves 57a, 57b. At the outer surface 56 of the receiving piece, the contours of the recesses 58a, 58b may have a substantially rectangular shape.

[0027] Each of the recesses 58a, 58b is defined by an upper surface 581 toward the top end 5a of the receiving piece 5 and by a lower surface 582 toward the bottom end 5b. As best shown in Figure 9, in the outer surface 56 of the receiving piece 5, the lower surfaces 582 of the recesses 58a, 58b are located at substantially the same first distance d1 from the top end 5a of the receiving piece 5 as the lower surfaces 572 of the respective grooves 57a, 57b. In particular, the lower surfaces 582 of the recesses 58a, 58b may be flush with the lower surfaces 572 of the grooves 57a, 57b.

[0028] The upper surfaces 581 of the recesses 58a, 58b are located at a third distance d3 from the top end 5a of the receiving piece 5, which may be smaller than the second distance d2 of the upper surfaces 571 of the grooves 57a, 57b from the top end 5a of the receiving piece 5. The upper and lower surfaces 581, 582 close the recesses 58a, 58b towards both the top end 5a and the bottom end 5b of the receiving piece.

[0029] The upper surface 581 and the lower surface 582 of the recesses 58a, 58b may extend substantially perpendicular to the central axis C, from the outer surface 56 of the receiving part, in a direction toward the central axis C, i.e., toward the passage 51. In this embodiment, the upper surface 581 and the lower surface 582 are generally planar surfaces extending from the outer surface 56 deep into the receiving part 5. Side walls 583 or bottoms of the recesses 58a, 58b define the recesses deep.

[0030] The recesses 58a, 58b have a maximum depth t2 from the outer surface 56 of the receiving piece 5 to a point of the recess that extends most inwardly into the receiving piece 5. The side walls 583 of the recesses 58a, 58b may have a curved shape that extends inwardly into the receiving piece from each end 580a, 580b of the outer surface 56 of the receiving piece 5. Preferably, the side walls 583 are cylindrical in shape, with the axis of the cylinder being substantially parallel to the central axis C.

[0031] As can be seen from FIG. 11, the maximum depth t2 of the recesses 58a and 58b is greater than the depth t1 of the grooves 57a and 57b.

[0032] It should be understood that the shapes of the upper and lower surfaces 581, 582 and sidewalls 583 of recesses 58a, 58b are not limited to the planar or curved shapes of this embodiment. Rather, they may have any other shapes; for example, the upper and lower surfaces may have rounded or arcuate shapes, and / or the sidewalls 583 may have a planar shape. Depending on the shapes of the upper and lower surfaces 581, 582, for example, if the upper and lower surfaces are inclined toward each other or have rounded or arcuate shapes that intersect at a point farthest from outer surface 56 (not shown), sidewalls 583 may be omitted.

[0033] The recesses 58a, 58b may further include a notch 584 in the outer surface 56 of the receiving piece, extending from the upper surface 582 of the recesses 58a, 58b toward the upper end 580a of the receiving piece. The notch 584 may be located in the center of the recesses 58a, 58b between their two ends 580a, 580b and may have a curved shape. The depth of the notch 584 may be less than the depth of the recesses 58a, 58b and the depth of the grooves 57a, 57b.

[0034] Preferably, the groove 57a and recess 58a provided in the first leg 55a of the receiving part are arranged and formed symmetrically with respect to the groove 57b and recess 58b of the second leg 58b with respect to a plane including the central axis C and passing through the center of the U-shaped recess 54 of the receiving part 5.

[0035] Additionally, the legs 55a, 55b may include a notch 59 at each circumferential end of each leg 55a, 55b facing the substantially U-shaped recess 54. Each notch 59 may extend axially from a first end 59a of the notch 59 located at an upper surface 571 of the groove 57a, 57b to a second end 59b of the notch 59 located closer to the bottom end 5b of the receiving part 5 than a lower surface 572 of the groove 57a, 57b.

[0036] Additionally, a sloped surface 590 may be provided below the upper surface of each groove 57a, 57b and extending from each notch 59 toward the internal thread 55c. The sloped surface 590 facilitates insertion of a portion of an instrument into the receiving part 5.

[0037] The pressure element 6, which can be best seen in the cross-sectional views of Figures 14 and 17, may comprise a substantially cylindrical first portion 61 at its upper end 6a and a substantially cylindrical second portion 62 at its lower end 6b. The substantially cylindrical second portion 62 may be configured to extend at least partially around the inserted head 3 and may be at least partially flexible for clamping the inserted head. For example, the second portion 62 may comprise a plurality of longitudinal slits (not shown) that make the second portion 62 flexible. The inserted head 3 may be clamped by moving the pressure member 6 downward within the passage 51 of the receiving part 5 such that the second portion 62 of the pressure member 6 is compressed by the constriction 52 of the receiving part 5.

[0038] The first part 61 of the pressure element 6 may comprise a base 63 having a substantially V- or U-shaped profile and forming a rod support surface for an inserted rod, and two upright legs 64a, 64b on either side of the base 63. The upper ends of the legs 64a, 64b may be provided with stops cooperating with the receiving part 5 to prevent upward movement of the pressure element 6 in the receiving part.

[0039] A coupling device according to one embodiment, useful for coupling a bone anchor element 1 to a rod 10, may comprise a receiving part 5 for receiving the rod 10 and the head 3 of the bone anchor element 1 therein, and a locking device in the form of a pressure element 6 configured to apply pressure to the head 3 to secure it in the receiving part 5. The coupling device may together with the bone anchor element form, for example, a polyaxial bone anchor device in which the shank is pivotable relative to the receiving part, and / or a uniplanar bone anchor device in which the pivotal movement of the shank relative to the receiving part is restricted to a single plane, and / or a monoaxial bone anchor device in which the shank can assume a single pre-defined angle relative to the receiving part. The bone anchor device may be of a bottom-loading type in which the head is insertable into the receiving part from its bottom end 5b, or of a top-loading type in which the head is insertable into the receiving part from its top end 5a.

[0040] The receiving part may have other shapes as shown in the embodiments. In particular, the receiving part may have any shape that allows it to pivotally accommodate the head of the bone anchor device. The receiving part may also have a structure that allows the bone anchor element to pivot at a greater angle to one side than to the other. In the case of a uniaxial coupling device, the receiving part may be fixedly connected to the shank or may be formed seamlessly with the shank, thereby making it possible to omit the head.

[0041] The pressure element may have other shapes as shown in the embodiments. The pressure element 6 in the above-described embodiment is a monolithic part. However, the pressure element may be formed from two or more parts configured to cooperate with each other to secure the head in the receiving part. The pressure element may also only be inserted over the head from above so that the head can pivot in a seat provided directly on the receiving part. Instead of a pressure element, any other locking device configured to secure the head in the receiving part may be implemented, such as an outer ring arranged at least partially around the head receiving part of the receiving part and configured to apply a clamping force to the head receiving part to secure the inserted head therein.

[0042] The receiving part and the parts and portions of the coupling device may be made of any material, preferably a biocompatible material such as titanium or stainless steel or any other biocompatible metal or metal alloy, or a plastic material. A Ni-Ti alloy, such as Nitinol, may be used as a biocompatible alloy. Other materials may be magnesium or magnesium alloys, and biocompatible plastic materials may be, for example, polyether ether ketone (PEEK) or poly-L-lactide acid (PLLA). The parts may be made of the same or different materials.

[0043] A first embodiment of an instrument configured to engage with a receiving part 5 will now be described with further reference to Figures 12 to 14. This embodiment is an example of an instrument configured to engage with grooves 57a, 57b. In the figures, only the lower part of the tubular portion 100 of the instrument is shown. Specifically, the tubular portion 100 of the instrument extends along a longitudinal axis L from an upper end (not shown) to a second end 100b. The tubular portion 100 may be substantially cylindrical.

[0044] The tubular portion 100 is provided with two longitudinal slits 101 that open toward the second end 100b and extend from the second end 100b along the longitudinal axis L. Each slit may terminate in an enlarged portion 101a at a distance from the second end 100b. The slits 101 form two arms 102a, 102b of the tubular portion 100. The slits 101 render the tubular portion at least partially flexible, such that the arms 102a, 102b are expandable away from each other and compressible toward each other.

[0045] The outer diameter of the tubular portion 100 may decrease toward the second end 100b. For example, in this embodiment, the tubular portion 100 of the instrument includes a first cylindrical segment-shaped portion 103a and a second cylindrical segment-shaped portion 103c adjacent the second end 100b, the outer diameter of the second cylindrical segment-shaped portion 103c being smaller than the diameter of the first cylindrical segment-shaped portion 103a. The outer diameters of the first and second cylindrical segment-shaped portions may gradually decrease to form an intermediate constriction portion 103b.

[0046] The inner diameter of the tubular portion 100 is such that the arms fit smoothly around the outer surface 56 of the receiving part and engage the receiving part therebetween.

[0047] On the inner surface of the second cylindrical segment-shaped portion 103c, each arm 102a, 102b is provided with a circumferentially extending rib 104 configured to engage with a circumferential groove 57a, 57b provided on the outer surface 56 of the arms 55a, 55b of the receiving part 5.

[0048] Specifically, the circumferential rib 104 may include an upper surface 105 and a lower surface 106 that define the rib toward the first end (not shown) and the second end 100b of the tubular portion 100, and a sidewall 107 connecting the upper and lower surfaces 105, 106 of the rib. The upper and lower surfaces 105, 106 may be inclined with respect to the longitudinal axis L and are formed so that the rib 104 fits into the grooves 57a, 57b, respectively. More specifically, the upper and lower surfaces 105, 106 abut against upper and lower surfaces 571, 572 of the grooves 57a, 57b, respectively, and the sidewall 107 of the circumferential rib 104 may abut against the sidewall 573 of the grooves 57a, 57b when the tubular portion 100 is attached to the receiving part 5.

[0049] The circumferential rib 104 may extend along the entire circumferential width of each arm 102a, 102b.

[0050] In use, the tubular portion 100 of the device is advanced by its second end 100b toward the top end 5a of the receiving part 5, positioning the tubular portion on the receiving part. Further advancement of the tubular portion 100 toward the bottom end 5b of the receiving part spreads the arms 102a, 102b of the tubular portion apart. The rounded edges at the top end of the receiving part 5a facilitate and assist in spreading the arms of the tubular portion 100. Finally, the circumferential ribs 104 on the inner surface of the arms 102a, 102b snap into the circumferential grooves 57a, 57b in the respective legs 55a, 55b of the receiving part 5, again compressing the arms 102a, 102b and connecting the tubular portion 100 to the receiving part 5.

[0051] Alternatively, to mount the tubular portion 100 on the receiving part 5, the tubular portion 100 can be advanced towards the receiving part with its arms 102a, 102b positioned circumferentially, i.e., between the legs 55a, 55b of the receiving part 5, in the position of the substantially U-shaped recess 54 of the receiving part. When the circumferential ribs 104 are in the axial position of the circumferential grooves 57a, 57b, the tube 100 is rotated about its longitudinal axis L so that the circumferential ribs 104 enter the circumferential grooves 57a, 57b.

[0052] A second embodiment of an instrument configured to engage with the receiving part 5 will now be described with further reference to Figures 15-17. This embodiment is an example of an instrument configured to engage with the recesses 58a, 58b. In the figures, only the lower part of the tubular portion 200 of the instrument is shown. The tubular portion 200 of the second instrument is similar to the tubular portion 100 of the first instrument described above, and similar features and elements are designated with the same reference numerals in the figures. Therefore, only the differences between the second instrument and the first instrument will be described below.

[0053] Instead of the circumferential rib 104 of the tubular portion 100 of the first instrument, the tubular portion 200 of the second instrument includes, on the inner surface of the second cylindrical segment-shaped portion 103c, a protrusion 204 provided on each arm 102a, 102b configured to engage with a recess 58a, 58b provided on the outer surface 56 of the receiving part 5.

[0054] The protrusion 204 may be formed at a circumferentially intermediate portion of each arm 102a, 102b. In the circumferential direction of the arm, the protrusion 204 may extend along a length between the first end 580a and the second end 580b that is equal to or slightly less than the width of the recess 58a, 58b in the receiving part 5. The contour of the protrusion 204 in the plane of the inner surface of the arm may be substantially rectangular.

[0055] The protrusion 204 may have an upper surface 205 and a lower surface 206 that define the protrusion toward the first end (not shown) and the second end 100b of the tubular portion 200, and a sidewall 207 connecting the upper and lower surfaces 205, 206 of the protrusion 204. The upper and lower surfaces 205, 206 may be substantially flat and extend substantially perpendicular to the longitudinal axis L. The sidewall 207 may have a curved shape complementary to the curved shape of the sidewall 583 of the recesses 58a, 58b provided in the receiving part 5. The thickness of the protrusion 204 between the inner surface of each arm 102a, 102b and the sidewall 207 may be substantially equal to the depth of the recesses 58a, 58b. More generally, the shape of the protrusion 204 may be such that the protrusion can engage with the recesses 58a, 58b. More specifically, the upper and lower surfaces 205, 206 of the protrusion 204 may be shaped and positioned to abut the upper and lower surfaces 581, 582 of the recesses 58a, 58b, respectively, and the sidewall 207 of the protrusion 204 may abut the sidewall 583 of the recesses 58a, 58b when the tubular portion 200 is mounted on the receiving part 5. However, the protrusion need not be configured to engage with the grooves 57a, 57b.

[0056] The protrusion 204 may have a protruding portion 208 shaped and arranged to engage with a notch 584 in the recesses 58a, 58b provided in the outer surface 56 of the receiving part 5 when the protrusion 204 engages with the recesses 58a, 58b.

[0057] In another example of a receiving part 5' shown in Figure 18, a receiving part is provided in which the legs 55a, 55b do not have the circumferential grooves 57a, 57b. Therefore, the receiving part 5' shown in Figure 18 only has the recesses 58a, 58b provided in the legs 55a, 55b, and the receiving part 5' can be used with the second instrument described above with reference to Figures 15 to 17.

[0058] In yet another example of a receiving part 5" shown in Figure 19, a receiving part is provided which does not have recesses 58a, 58b in the legs 55a, 55b. Therefore, the receiving part 5" shown in Figure 19 only has circumferential grooves 57a, 57b provided in its legs 55a, 55b, and the receiving part 5" can be used with the first instrument described above with reference to Figures 12 to 14.

[0059] Therefore, the receiving part 5 according to the present invention shown in Figures 1 to 17 can be used with both the type of instrument configured to engage with the receiving part 5' shown in Figure 18 and the type of instrument configured to engage with the receiving part 5" shown in Figure 19.

Claims

1. A receiving part of a bone anchor device, said receiving part (5) comprising: a first end (5a), a second end (5b) opposite the first end (5a), and a central axis (C) extending through the first end (5a) and the second end (5b); a substantially U-shaped recess (54) adjacent said first end (5a) for receiving a rod (10), said substantially U-shaped recess (54) forming two free legs (55a, 55b); a circumferential groove (57a, 57b) in the outer surface (56) of at least one of the legs (55a, 55b), the circumferential groove (57a, 57b) being defined in the direction of the central axis (C) by an upper surface (571) and a lower surface (572); a recess (58a, 58b) in the outer surface (56) of the at least one leg, the recess (58a, 58b) being defined in the direction of the central axis (C) by an upper surface (581) and a lower surface (582); Equipped with On the outer surface (56) of the receiving part (5), the lower surfaces (582) of the recesses (58a, 58b) and the lower surfaces (572) of the grooves (57a, 57b) are at substantially the same distance (d １ ) A receiving part of a bone anchor device provided on the

2. 2. The receiving part according to claim 1, wherein the upper surfaces (581) of the recesses (58a, 58b) on the outer surface (56) of the receiving part are located at a shorter distance from the first end (5a) of the receiving part than the upper surfaces (571) of the grooves.

3. The depth (t １ ) is the depth (t ２ 3. The receiving part according to claim 1, wherein the receiving part has a diameter greater than 1 / 2 mm.

4. The receiving part according to any one of claims 1 to 3, wherein the grooves (57a, 57b) extend in the circumferential direction of the receiving part (5) in an arcuate shape along the entire circumferential extension of the at least one leg (55a, 55b).

5. 5. The receiving part according to claim 1, wherein the recesses (58a, 58b) extend in the circumferential direction of the receiving part (5) from the first end (580a) to the second end (580b) along a length that is shorter than the circumferential extension of the grooves (57a, 57b).

6. 6. The receiving part according to claim 1, wherein the recess (58a, 58b) extends in the circumferential direction of the receiving part from a first end (580a) to a second end (580b), and the depth of the recess (58a, 58b) from the outer surface (56) of the receiving part toward the central axis (C) increases from the first end and / or the second end of the recess toward an intermediate portion of the recess spaced from the first end and the second end.

7. 7. The receiving part according to claim 1, wherein the grooves (57a, 57b) intersect with the recesses (58a, 58b) in the circumferential direction.

8. 8. Receiving piece according to any one of claims 1 to 7, wherein the recesses (58a, 58b) are closed towards both the first end (5a) and the second end (5b) of the receiving piece.

9. 9. A receiving piece according to any one of claims 1 to 8, wherein the upper surface (571) and / or the lower surface (572) of the groove is inclined from the outer surface (56) of the receiving piece towards the first end (5a).

10. 10. The receiving piece according to any one of claims 1 to 9, wherein the upper surface (581) and / or the lower surface (582) of the recess (58a, 58b) extends substantially perpendicular to the central axis (C).

11. 11. The receiving piece according to claim 1, wherein a notch (584) is provided in the outer surface (56) of the at least one leg (55a, 55b), the notch (584) extending from the upper surface (581) of the recess (58a, 58b) towards the first end (5a) of the receiving piece.

12. 12. The receiving part according to claim 1, wherein the at least one leg (55a, 55b) comprises a notch (59) at the circumferential end of the leg facing the substantially U-shaped recess (54), the notch (59) extending in the direction of the central axis (C) from a first end (59a) at the upper surface (571) of the groove (57a, 57b) to a second end (59b) of the notch (59) beyond the lower surface (572) of the groove.

13. Receiver part according to any one of claims 1 to 12, wherein the grooves (57a, 57b) and / or the recesses (58a, 58b) are provided in both free legs (55a, 55b).

14. A coupling device for connecting a bone anchor element (1) to a rod (10), said bone anchor element (1) comprising a shank (2) for fixing to a bone, said coupling device comprising: A receiving part (5) according to any one of claims 1 to 13, Preferably, the bone anchor element comprises a head, and the receiving part is configured to receive the head (3) of the bone anchor element, More preferably, said coupling device comprises a locking device (6) configured to cooperate with said receiving part (5) to fix said head part (3) to said receiving part.

15. A system of at least one tool and a receiving part according to any one of claims 1 to 13 or a connecting device according to claim 14, wherein the tool comprises a tubular part (100, 200) having two arms (102a, 102b), at least one arm comprising at least one protrusion (104, 204) on its inner surface adapted to engage in the groove (57a, 57b) and / or the recess (58a, 58b) of the receiving part (5), Preferably, the device is a first device and the at least one protrusion is formed as a circumferentially extending rib (104) configured to engage in the groove (57a, 57b) of the receiving part; and / or Preferably, the tool is a second tool, and the at least one protrusion (204) is formed in an intermediate portion of the arm in a circumferential direction of the second tool and configured to engage with the recess (58a, 58b) of the receiving part.

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