Crown locking mechanism for spinal implant

Abstract

A spinal screw assembly includes a screw, a connector body, a bore, a crown positioned in the connector body, and a biasing member. The screw has an at least partially rounded head. The connector body has a base and at least two side walls extending from the base. The base includes a base opening. The at least two side walls form a support recess opening defining a central axis. The bore is in one of the at least two side walls of the connector body. The bore extends to the support recess opening along a bore axis transverse to the central axis. The crown has a first end sized to receive the at least partially rounded head of the screw. The biasing member is moveable along the bore axis and engages a slot of the crown to limit the crown's axial movement along the central axis in the unbiased state.

Description

CROWN LOCKING MECHANISM FOR SPINAL IMPLANTTECHNICAL FIELD

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 594,659, filed October 31, 2023, the entire content of which is incorporated herein by reference.TECHNICAL FILED

[0002] The present disclosure relates to a spinal screw assembly that supports a spinal rod for use in a spinal procedure.BACKGROUND

[0003] Treatment of spinal disorders, such as degenerative disc disease, disc herniations, scoliosis or other curvature abnormalities, and fractures, often requires surgical treatments. For example, implants may be used to preserve motion between vertebral members.

[0004] Surgical treatment typically involves the use of longitudinal members, such as spinal rods. Spinal rods may be attached to the exterior of two or more vertebral members to assist with the treatment of a spinal disorder. Spinal rods may provide a stable, rigid column that helps bones to fuse, and may redirect stresses over a wider area away from a damaged or defective region. Also, rigid spinal rods may help in spinal alignment.SUMMARY

[0005] According to one embodiment, a spinal screw assembly includes a screw, a connector body, a first bore, a crown, and a biasing member. The screw has a threaded body and an at least partially rounded head. The connector body has a base and at least two side walls extending from the base. The base includes a base opening sized to receive the at least partially rounded head of the screw. The at least two side walls are spaced apart to form a support recess opening defining a central axis. The first bore is defined in one of the at least two side walls of the connector body. The first bore extends to the support recess opening along a bore axis transverse to the central axis. The crown ispositioned in the connector body between the base and the support recess opening. The crown has a first end sized to receive the at least partially rounded head of the screw and a second end having a slot extending parallel to the central axis. The biasing member is positioned in the first bore and is moveable along the bore axis between a biased state and an unbiased state. The biasing member is constrained at one end entirely within the first bore by the first end of the crown in the biased state. The one end of the biasing member partially extends into the support recess opening in the unbiased state to engage the slot of the crown to limit the axial movement of the along the central axis.

[0006] According to another embodiment, a method of installing a spinal screw assembly in a spinal procedure is disclosed. The spinal screw assembly includes a screw, a connector body, a bore, a crown, and a biasing member. The screw includes a threaded body and an at least partially rounded head. The connector body has a base and at least two side walls extending from the base. The base has a base opening. The at least two side walls extend from the base to form a support recess opening defining a central axis. The bore is defined in one of the at least two side walls of the connector body and extends into the support recess opening. The crown is positioned in the connector body and has a first end and a second end. The second biasing member is positioned in the bore. The method includes positioning the connector body on the at least partially rounded head of the screw. The method also includes moving the connector body in a downward direction until the at least partially rounded head of the screw is received in the base opening. The method also includes moving the crown in the downward direction onto the at least partially rounded head of the screw until the at least partially rounded head is received in the first end of the crown. Moving the crown in the downward direction causes the biasing member to extend at least partially into the support recess opening and engage a slot formed in the second end of the crown.

[0007] According to another embodiment, a method of manufacturing a spinal screw assembly is disclosed. The spinal screw assembly includes a connector body, a bore, a crown, and a biasing member. The connector body has a base and at least two side walls extending from the base to form a support recess opening. The bore is defined in the connector body and extends into the support recess opening. The crown is positioned between the base and the at least two side walls. The biasing member has a first end cap, asecond end cap, and a spring therebetween. The method includes inserting the crown into the connector body such that the crown is positioned between the base and the support recess opening. The method also includes applying a spot weld between the crown and the connector body to secure the crown to the connector body. The method also includes moving the biasing member into the bore until the second cap contacts the crown. The method also includes compressing the biasing member. The method also includes applying a weld to the first end cap to an outer periphery of the connector body.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 invention and together with the written description serve to explain the principles, characteristics, and features of the invention.In the drawings:

[0009] FIG. 1A illustrates a perspective view of the spinal screw assembly, according to some aspects of the present disclosure.

[0010] FIG. IB illustrates a perspective view of the spinal screw assembly of FIG. 1A rotated in a first transversal direction.

[0011] FIG. 1C illustrates a perspective view of the spinal screw assembly of FIG. 1A rotated in a second transversal direction.

[0012] FIG. 2 illustrates an exploded front view of the spinal screw assembly of FIG. 1A.

[0013] FIG. 3 illustrates a perspective view of a connector body of the spinal screw assembly of FIG. 1A.

[0014] FIG. 4 illustrates a front section view of the connector of FIG. 3 taken along the line 4-4.

[0015] FIG. 5 illustrates a perspective view of the crown of the spinal screw assembly of FIG. 1A.

[0016] FIG. 6 illustrates a front section view of the crown of FIG. 5 taken along the line 6—6.

[0017] FIG. 7A illustrates a front view of a biasing member of the spinal screw assembly of FIG. 1A in a biased state.

[0018] FIG. 7B illustrates a section view of the biasing member in FIG. 7A taken along the line 7B — 7B.

[0019] FIG. 8A illustrates a front view of a biasing member of the spinal screw assembly of FIG. 1A in an unbiased state.

[0020] FIG. 8B illustrates a section view of the biasing member in FIG. 8A taken along the line 8B — 8B.

[0021] FIG. 9 illustrates a front section view of the connector body and crown portions of the spinal screw assembly of FIG. 1A in the unlocked position.

[0022] FIG. 10 illustrates a front section view of the connector body, crown, and screw portions of the spinal screw assembly of FIG. 1A in the locked position.

[0023] FIG. 11 is a flowchart illustrating a method of installing the spinal screw assembly, according to some aspects of the present disclosure.

[0024] FIGS. 12-17 illustrate front section views of the installation process of the spinal screw assembly of FIG. 1A.

[0025] FIG. 18 is a flowchart illustrating a method of assembly the spine screw assembly, according to some aspects of the present disclosure.

[0026] FIGS. 19-22 illustrate front section views of the assembly process of the spinal screw assembly of FIG. 1A.DETAILED DESCRIPTION

[0027] The following description of the depicted embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Beforeany embodiments of the disclosure are explained in detail, it is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways.

[0028] Embodiments of the presently disclosed system are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. In the following description, well- known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

[0029] Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Use of “including,” “comprising,” “having,” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “supported” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings.

[0030] The components of the spinal screw assembly described herein can be fabricated from biologically acceptable materials suitable for medical applications, including metals, synthetic polymers, ceramics, and bone material. Examples of such materials include, but are not limited to, a titanium alloy (e.g., Ti-6A1-4V), pure titanium, cobalt -chromium (CoCr), and polyether ether ketone (PEEK).

[0031] In spinal procedures, a rod is used to align vertebrates of the spine. The rod is connected to the vertebrates by a spinal screw assembly having a connector body and a screw. The screw is inserted into the vertebrates and the connector body supports at least one end of the rod. The other end of the rod may be connected to a second spinal screw assembly. The screw in the spinal screw assembly may be semi-rigid in the sagittal plane but may be able to flex in the coronal plane to ease the placement of the rods and spinal screw assemblies during the spinal procedures. To allow for the flexibility of the screw assembly in the coronal plane, the spinal screw assembly must have increased strength tobe able to withstand the amount of bending movement. The disclosed embodiment of the spinal screw assembly 10 has an increased strength compared to traditional spinal screw assemblies due to the crown locking functionality provided by a set of biasing members.

[0032] Referring to FIGS. 1A-1C, a spinal screw assembly 10 is illustrated according to some aspects of the present disclosure. The spinal screw assembly 10 can support an end of a rod 14. As shown in FIGS. 1A-1C, the spinal screw assembly 10 is semi-rigid in the sagittal plane but is pivotable along the coronal plane. FIGS. IB and 1C show the spinal screw assembly 10 flexed in the coronal plane in a first direction and flexed in a second, opposite direction.

[0033] Turning now to FIG. 2, a spinal screw assembly 10 is shown in detail. The spinal screw assembly 10 includes a screw 18, a connector body 22, and a crown 26 disposed in the connector body 22. The screw 18 includes a first end 38, a second end 42, and a body 46 extending between the first end 38 and the second end 42. The first end 38 includes a pointed tip that is inserted into the spine during a spinal procedure. The second end 42 defines an at least partially rounded head. The second end 42 is received in the connector body 22. The body 46 is a threaded body. The screw 18 can be formed from Ti-6al-4V, though other biologically acceptable materials are also contemplated.

[0034] In addition to FIG. 2, aspects of the connector body 22 are further illustrated in more detail in FIGS. 3-4. The connector body 22 connects the rod 14 (see FIG. 1) to the screw 18. The connector body 22 can be formed from CoCr, though other biologically acceptable materials are also contemplated. The connector body 22 is generally U-shaped in the illustrated embodiment, though other shapes acceptable for receiving the rod 14 are also contemplated. The connector body 22 may include a base 50, a first side wall 54, and a second side wall 58.

[0035] The base 50 includes a base opening 62 that is sized to receive the second end 42 of the screw 18. The base opening 62 includes a first groove 66 and a second groove 70. The first groove 66 is positioned lower than the second groove 70. The second groove 70 is larger (e.g., has a larger diameter) than the first groove 66.

[0036] In some implementations, the base opening 62 further includes a retaining ring 74 (see FIG. 9). In some implementations, the retaining ring 74 is the sole retaining ring in the base opening 62. The retaining ring 74 is moveable between the first groove 66 and the second groove 70. The retaining ring 74 is made of flexible material that is able to contract and expand. The retaining ring 74 is in its natural state when the retaining ring 74 is disposed in the first groove 66. The retaining ring 74 can be positioned into an extended state when the retaining groove is disposed in the second groove 70. When the second end 42 of the screw 18 is received in the base opening 62, the retaining ring 74 engages the second end 42 of the screw 18. The second end 42 of the screw 18 moves the retaining ring 74 between the first groove 66 and the second groove 70. The retaining ring 74 limits the axial movement of the screw 18 in a first direction when the retaining ring 74 is in the first groove 66. More specifically, the retaining ring 74 limits the axial movement of the screw 18 in the downward direction when the retaining ring 74 is in the first groove 66.In the illustrated embodiment, the retaining ring 74 is a C-ring. In some embodiments, the retaining ring 74 may be an O-ring.

[0037] With continued reference to FIGS. 2-4, the first side wall 54 and the second side wall 58 extend from the base 50. The first and second side walls 54, 58 are spaced apart to form a central opening 86 (e.g., a support recess opening). The central opening 86 defines a central axis 90. The central opening 86 is contiguous with the base opening 62.

[0038] Each of the side walls 54, 58 includes an inner surface 78 and an outer surface 82 (e.g., the outer periphery). Together, the first side wall 54 and the second side wall 58 define a threaded interface 94. The inner surface 78 of the first side wall 54 defines a first portion of the threaded interface 94 and the inner surface 78 of the second side wall 58 defines a second portion of the threaded interface 94. The threaded interface 94 may engage a threaded fastener to secure the rod 14 (see FIG. 1) to the spinal screw assembly 10.

[0039] The connector body 22 further includes a first bore 98 defined in the first side wall 54 and a second bore 102 defined in the second side wall 58. The first and second bores 98, 102 are defined at approximately the same axial position on the side walls 54, 58. The second bore 102 is diametrically opposed to the first bore 98. More specifically, the first and second bores 98, 102 are positioned between the threaded interface 94 and thebase 50 of the connector body 22. The first and second bores 98, 102 extend from the outer surface 82 of their respective side wall to the inner surface 78 of their respective side wall. Said another way, the first and second bores 98, 102 extend from the outer surface 82 of the side wall to or into the central opening 86. The first and second bores 98, 102 extend along a bore axis 106. The bore axis 106 is transverse to the central axis 90 of the central opening 86. More specifically, the bore axis 106 is perpendicular to the central axis 90 of the central opening 86.

[0040] The first and second side walls 54, 58 may further include a bore 110. Bore 110 allows various instruments, not shown, to be mated with connector body 22. The instruments will be used to help manipulate rod 14 into the connector body 22.

[0041] In addition to FIG. 2, the crown 26 is illustrated in more detail in FIGS. 5-6. The crown 26 is supported by the connector body 22 and supports the spinal rod 14 (see FIG. 1) within the central opening 86. More specifically, the crown 26 is positioned in the connector body 22 between the base 50 and the central opening 86. The crown 26 can be formed from pure titanium, though other biologically acceptable materials may also be used.

[0042] The crown 26 may include a first end 114 and a second end 118. The first end 114 includes an opening 122 that is sized to receive the second end 42 of the screw 18. The second end 118 has a curved surface which supports the rod 14 (see FIG. 1). The second end 118 includes a first slot 126 and a second slot 130 that is opposite the first slot 126. The first and second slots 126, 130 extend in a direction that is parallel to the central axis 90 (see FIG. 4).

[0043] With reference to FIGS. 2 and FIGS. 7A-9, the spinal screw assembly 10 includes a first biasing member 30 and a second biasing member 34. The first biasing member 30 is received in the first bore 98, and the second biasing member 34 is received in the second bore 102. The first and second biasing members 30, 34 include first end cap 134, a second end cap 138, and a spring 142 positioned therebetween.

[0044] The biasing members 30, 34 are moveable between a biased state and an unbiased state. The biasing members 30, 34 move from the biased state to the unbiasedstate in response to the axial movement of the crown 26. In the biased state (shown in FIGS. 7A-7B and 9), the spring 142 is compressed such the first end cap 134 is in close proximity with the second end cap 138. In some embodiments, the spring 142 is compressed such that the first end cap 134 is engaged with the second end cap 138. Additionally, in the biased state, the biasing members 30, 34 contact the first end 114 of the crown 26 such that the biasing members 30, 34 are constrained at one end entirely within the bores 98, 102 by the first end 114 of the crown 26.

[0045] In the unbiased state (shown in FIGS. 8A-8B and 10), the spring 142 is extended such that the first end cap 134 is further away with the second end cap 138. Additionally, in the unbiased state, the biasing members 30, 34 are engaged with the slots 126, 130 of the second end 118 of the crown 26. The first end cap 134 of the biasing members 30, 34 extends at least partially into the central opening 86 to engage the slots 126, 130.

[0046] In FIG. 9, a cross-section of the connector body 22 and crown 26 portions of the spinal screw assembly 10 (see FIGS. 1A and 2) is illustrated in the unlocked state. In the unlocked state, the crown 26 is positioned between the base 50 and the central opening 86 of the connector body 22. The first end 114 of the crown 26 is welded to the base 50 of the connector body 22 by spot welds 150. The spot welds 150 secure the crown 26 to the connector body 22 and prevent the crown 26 from falling out of the connector body 22 while the spinal screw assembly 10 is being transported and installed. The spot welds 150 are breakable welds which break when a predetermined amount of force is applied to the crown 26 in the downward direction, break as the crown 26 moves in the downward direction, and break as the biasing members 30, 34 move between the biased and unbiased state. In some implementations, the force required to break the spot welds 150 may be between 200N-500N. The number of spot welds 150 between the crown 26 and the connector body 22 is dependent on the desired breaking force. Additionally, in the unlocked state, the biasing members 30, 34 are in the biased state and engage the first end 114 of the crown 26 and the biasing members 30, 34 are received entirely in the bores 98, 102.

[0047] In FIG. 10, a cross-section of the connector body 22, crown, 26 and screw 18 portions of the spinal screw assembly 10 in the locked state is illustrated. In the lockedstate, the second end 42 of the screw 18 and the first end 114 of the crown 26 are received in the base opening 62 of the connector body 22. The second end 42 of the screw 18 is also received in the opening 122 of the crown 26. The second end 42 of the screw 18 is engaged with the retaining ring 74 in the first groove 66, and the retaining ring 74 limits the axial movement of the screw 18 in the downward direction. The biasing members 30, 34 are in the unbiased state and extend at least partially into the central opening 86 to engage with the slots 126, 130 of the crown 26. The biasing members 30, 34 limit the axial movement of the crown 26 in the upward direction.

[0048] Referring to FIGS. 11-17, an exemplary method 200 of installing the present spinal screw assembly 10 is described. For example, once the first end 38 of the screw 18 is secured to the spine, at operational step 210, the user may place or position the connector body 22 on the second end 42 of the screw 18 (see FIG. 12). The user may align the base opening 62 with the second end 42 of the screw 18 such that the screw 18 is received in the base opening 62.

[0049] At operational step 220, the user may move the connector body 22 in the downward direction (e.g., toward the first end 38 of the screw 18). As shown in FIGS. 13- 15, as the connector body 22 moves in the downward direction, the second end 42 of the screw 18 engages with the retaining ring 74 in the first groove 66 (FIG. 13). As the connector body 22 moves further in the downward direction, the screw 18 moves the retaining ring 74 from the first groove 66 to the second groove 70 (FIG. 14). When the retaining ring 74 is in the second groove 70, it expands to fit the second groove 70. The connector body 22 may be moved in the downward direction until the second end 42 of the screw 18 is completely received in the base opening 62 (FIG. 15). The connector body 22 may be moved in the downward direction until a portion of the screw 18 is received in the opening 122 of the crown 26.

[0050] At operational step 230, the user may move the connector body 22 in the upward direction (e.g., toward the second end 42 of the screw 18) to lock the connector body 22 to the screw 18. As shown in FIG. 16, as the connector body 22 moves in the upward direction, the second end 42 of the screw 18 moves the retaining ring 74 from the second groove 70 to the first groove 66. The retaining ring 74 contracts to fit in the first groove 66. The retaining ring 74 engages the second end 42 of the screw 18. Theretaining ring 74 prevents or otherwise limits the relative movement between the screw 18 and the connector body 22 in one direction. More specifically, the retaining ring 74 inhibits or otherwise limits the axial movement of the connector body 22 in the upward direction.

[0051] At operational step 240, the user may move the crown 26 in the downward direction. The user may use a tool to push the crown 26 in the downward direction. The crown 26 is moved relative to the connector body 22 and the screw 18. The crown 26 is moved in the downward direction until the second end 42 of the screw 18 is received in the opening 122 of the crown 26 (see FIG. 17). When the crown 26 is moved downward, the first and second biasing members 30, 34 move into the unbiased state and at least partially extend into the central opening 86 to engage the first and second slots 126, 130 of the crown 26. Once the crown 26 is moved in the downward direction, the spinal screw assembly 10 is in the locked position, and the biasing members 30, 34 inhibit the axial movement of the crown 26 relative to the connector body 22 in one direction. More specifically, the biasing members 30, 34 inhibit or otherwise limit the axial movement of the crown 26 in the upward direction.

[0052] As the user moves the crown 26 in the downward direction, the force of the movement may break the spot weld 150 between the crown 26 and the connector body 22. The break is a controlled break. The user may stop moving the crown 26 in the downward direction after the weld 150 breaks. The breaking of the weld 150 serves as haptic feedback to the user to indicate the spinal screw assembly 10 has been moved to the locked state.

[0053] Referring to FIGS. 18-22, an exemplary method 300 of manufacturing the present spinal screw assembly 10 is described. For example, at operational step 310, the user may insert the crown 26 into the connector body 22. As shown in FIG. 19, the connector body 22 may be placed on a rod 160 such that the base opening 62 is exposed and accessible. In some aspects, the user may insert the crown 26 into the connector body 22 through the base opening 62 of the connector body 22 such that the crown 26 rests on the rod 160. In some aspects, the user may insert the crown 26 into the connector body 22 such that the crown 26 is positioned between the base 50 and the central opening 86.

[0054] At operational step 320, the user may apply a spot weld 150 between the crown 26 and the connector body 22. As shown in FIG. 20, in some aspects, the user may apply multiple spot welds 150 between the crown 26 and the connector body 22. The spot welds 150 secure the crown 26 to the connector body 22.

[0055] At operational step 330, the user may position the first and second biasing members 30, 34 in the first and second bores 98, 102, respectively (see FIG. 21). For example, the user may move the first and second biasing members 30, 34 into the first and second bores 98, 102 until the second end cap 138 of the first and second biasing members 30, 34 contacts the crown 26. In some aspects, the first and second biasing members 30, 34 may be inserted into the first and second bores 98, 102 by inserting the second end cap 138 into the first and second bores 98, 102. Then, the spring 142 is inserted into the first and second bores 98, 102 and into the second end cap 138. Afterwards, the first end cap 134 is inserted into the first and second bores 98, 102 and is moved to cover the spring 142.

[0056] At operational step 340, the user may compress the first and second biasing members 30, 34. In some aspects, the user may compress the first and second biasing members 30, 34 by moving the first end cap 134 into the first and second bores 98, 102 until the first end cap 134 contacts the second end cap 138.

[0057] At operational step 350, the user may apply a weld between the first end cap 134 and the outer surface 82 of the first and second side walls 54, 58. The weld may be a weld seam. The weld and the first end 114 of the crown 26 maintain the first and second biasing members 30, 34 in the biased state.

[0058] In some embodiments, the method 200 and the method 300 may include more operational steps or fewer operational steps. In some embodiments, the operational steps in the method 200 and the method 300 may occur in a different sequence then the sequence that the operational steps are presented in in this disclosure. In some embodiments, the operational steps in the method 200 and the method 300 may occur simultaneously or concurrently.

[0059] 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 invention should not be limited by any of the above-described exemplary embodiments but should be defined only in accordance with the claims and their equivalent.

[0060] The following examples are a non-limiting list of clauses in accordance with one or more techniques of this disclosure.

[0061] Example 1. A spinal screw assembly comprising: a screw having a threaded body and an at least partially rounded head; a connector body having a base and at least two side walls extending from the base, the base including a base opening sized to receive the at least partially rounded head of the screw, the at least two side walls being spaced apart to form a support recess opening defining a central axis; a first bore defined in one of the at least two side walls of the connector body, the first bore extending to the support recess opening along a bore axis transverse to the central axis; a crown positioned in the connector body between the base and the support recess opening, the crown having a first end sized to receive the at least partially rounded head of the screw and a second end having a slot extending parallel to the central axis; and a biasing member positioned in the first bore, the biasing member movable along the bore axis between a biased state and an unbiased state, the biasing member being constrained at one end entirely within the first bore by the first end of the crown in the biased state, the one end of the biasing member partially extending into the support recess opening in the unbiased state to engage the slot of the crown to limit axial movement of the crown along the central axis.

[0062] Example 2. The spinal screw assembly of Example 1, wherein the base opening of the connector body includes a first groove, a second groove, and a retaining ring moveable between the first groove and the second groove, wherein the retaining ring is in a compressed state when the retaining ring is disposed in the first groove, and wherein the retaining ring is in an extended state when the retaining ring is disposed in the second groove.

[0063] Example 3. The spinal screw assembly of Example 2, wherein the base opening of the connector body includes a single retaining ring.

[0064] Example 4. The spinal screw assembly of Example 2, wherein the retaining ring engages the at least partially rounded head of the screw, and wherein the retaining ring limits the axial movement of the screw along the central axis in a second direction when the retaining ring is positioned in the first groove.

[0065] Example 5. The spinal screw assembly of Example 1, further comprising a second biasing member positioned in a second bore in the connector body that is diametrically opposed to the first bore.

[0066] Example 6. The spinal screw assembly of Example 1, wherein the biasing member includes a first end cap, a second end cap, and a spring positioned between the first end cap and the second end cap, and wherein the second end cap extends at least partially into the support recess opening in the unbiased state.

[0067] Example 7. The spinal screw assembly of Example 6, wherein the first end cap is welded to an outer periphery of one of the at least two side walls.

[0068] Example 8. The spinal screw assembly of Example 1, wherein the first end of the crown is received in the base opening of the connector body when the biasing member is in the unbiased state.

[0069] Example 9. The spinal screw assembly of Example 1, further comprising a spot weld between the crown and the base of the connector body when the biasing member is in the biased state.

[0070] Example 10. The spinal screw assembly of Example 9, wherein the spot weld allows a controlled break as the biasing member moves from the biased state to the unbiased state.

[0071] Example 11. The spinal screw assembly of Example 1, wherein the biasing member Emits the axial movement of the crown in a first direction when the biasing member is in the unbiased state.

[0072] Example 12. The spinal screw assembly of Example 11, wherein the axial movement of the crown in a second direction along the central axis moves the biasing member from the biased state to the unbiased state.

[0073] Example 13. A method of installing a spinal screw assembly for use in a spinal procedure, the spinal screw assembly including, a screw having a threaded body and an at least partially rounded head, a connector body having a base and at least two side walls extending from the base, the base having a base opening, the at least two side walls being spaced apart to form a support recess opening defining a central axis, a bore defined in one of the at least two side walls of the connector body and extending into the support recess opening, a crown positioned in the connector body and having a first end and a second end, and a biasing member positioned in the bore, the method including: positioning the connector body on the at least partially rounded head of the screw; moving the connector body in a downward direction until the at least partially rounded head of the screw is received in the base opening; and moving the crown in the downward direction onto the at least partially rounded head of the screw until the at least partially rounded head is received in the first end of the crown, wherein moving the crown in the downward direction causes the biasing member to extend at least partially into the support recess opening and engage a slot formed in the second end of the crown.

[0074] Example 14. The method of Example 13, wherein moving the crown in the downward direction includes breaking a weld formed between the crown and the connector body.

[0075] Example 15. The method of Example 13, wherein moving the connector body in the downward direction causes the at least partially rounded head of the screw to move a retaining ring positioned in a first groove in the base opening of the connector body into a larger second groove in the base of the connector body.

[0076] Example 16. The method of Example 15, further comprising moving the connector body in an upward direction.

[0077] Example 17. The method of Example 16, wherein moving the connector body in the upward direction causes the retaining ring to return to the first groove in the connector body.

[0078] Example 18. A method of manufacturing a spinal screw assembly, the spinal screw assembly including a connector body having a base and at least two side walls extending from the base to form a support recess opening, a bore defined in the connector body extending into the support recess opening, a crown positioned between the base and the at least two side walls, and a biasing member having a first end cap, a second end cap, and a spring therebetween, the method including: inserting the crown into the connector body such that the crown is positioned between the base and the support recess opening; applying a spot weld between the crown and the connector body to secure the crown to the connector body; moving the biasing member into the bore until the second end cap contacts the crown; compressing the biasing member; and applying a weld to the first end cap to an outer periphery of the connector body.

[0079] Example 19. The method of Example 18, wherein moving the biasing member into the bore includes moving the second end cap into the bore, inserting the spring into the second end cap, and moving the first end cap over the spring.

[0080] Example 20. The method of Example 18, wherein compressing the biasing member includes moving the biasing the first end cap into the bore until the first end cap contacts the second end cap.

[0081] Example 21. A spinal screw assembly (10) comprising: a screw (18) having a threaded body (46) and an at least partially rounded head (42); a connector body (22) having a base (50) and at least two side walls (54, 58) extending from the base (50), the base (50) including a base opening (62) sized to receive the at least partially rounded head (42) of the screw (18), the at least two side walls (54, 58) being spaced apart to form a support recess opening (86) defining a central axis (90); a first bore (98) defined in one of the at least two side walls (54, 58) of the connector body, the first bore (98) extending to the support recess opening (86) along a bore axis (106) transverse to the central axis (90); a crown (26) positioned in the connector body (22) between the base (50) and the support recess opening (86), the crown (26) having a first end (122) sized to receive the at leastpartially rounded head (42) of the screw (18) and a second end (118) having a slot (126) extending parallel to the central axis (90); and a biasing member (34) positioned in the first bore (98), the biasing member (34) movable along the bore axis (106) between a biased state and an unbiased state, the biasing member (34) being constrained at one end entirely within the first bore (98) by the first end (122) of the crown (26) in the biased state, the one end of the biasing member (34) partially extending into the support recess opening (86) in the unbiased state to engage the slot (126) of the crown (26) to limit axial movement of the crown (26) along the central axis (90).

[0082] Example 22. The spinal screw assembly of Example 21, wherein the base opening (62) of the connector body (22) includes a first groove (66), a second groove (70), and a retaining ring (74) moveable between the first groove (66) and the second groove (70), wherein the retaining ring (74) is in a compressed state when the retaining ring (74) is disposed in the first groove (66), wherein the retaining ring (74) is in an extended state when the retaining ring (74) is disposed in the second groove (70), and wherein the retaining ring (74) is the sole retaining ring (74).

[0083] Example 23. The spinal screw assembly of Example 22, wherein the retaining ring (74) engages the at least partially rounded head (42) of the screw (18), and wherein the retaining ring (74) limits the axial movement of the screw (18) along the central axis (90) in a second direction when the retaining ring (74) is positioned in the first groove (66).

[0084] Example 24. The spinal screw assembly according to any of the proceeding claims, further comprising a second biasing member (34) positioned in a second bore (102) in the connector body (22) that is diametrically opposed to the first bore (98).

[0085] Example 25. The spinal screw assembly of according to any of the proceeding claims, wherein the biasing member (34) includes a first end cap (134), a second end cap (138), and a spring (142) positioned between the first end cap (134) and the second end cap (138), and wherein the second end cap (138) extends at least partially into the support recess opening (86) in the unbiased state.

[0086] Example 26. The spinal screw assembly of Example 25, wherein the first end (122) of the crown (26) is received in the base opening (62) of the connector body (22) when the biasing member (34) is in the unbiased state.

[0087] Example 27. The spinal screw assembly according to any of the proceeding claims, further comprising a spot weld (150) between the crown (26) and the base (50) of the connector body (22) when the biasing member (34) is in the biased state.

[0088] Example 28. The spinal screw assembly according to any of the proceeding claims, wherein the spot weld (150) allows a controlled break as the biasing member (34) moves from the biased state to the unbiased state.

[0089] Example 29. The spinal screw assembly according to any of the proceeding claims, wherein the biasing member (34) Emits the axial movement of the crown (26) in a first direction when the biasing member (34) is in the unbiased state.

[0090] Example 30. The spinal screw assembly according to any of the proceeding claims, wherein the axial movement of the crown (26) in a second direction along the central axis (90) moves the biasing member (34) from the biased state to the unbiased state.

[0091] Example 31. A method of installing a spinal screw assembly (200) for use in a spinal procedure, the spinal screw assembly (10) including, a screw (18) having a threaded body (46) and an at least partially rounded head (42), a connector body (22) having a base (50) and at least two side walls (54, 58) extending from the base (50), the base (50) having a base opening (62), the at least two side walls (54, 58) being spaced apart to form a support recess opening (86) defining a central axis (90), a bore (98) defined in one of the at least two side walls (54, 58) of the connector body (22) and extending into the support recess opening (86), a crown (26) positioned in the connector body (22) and having a first end (122) and a second end (118), and a biasing member (34) positioned in the bore (), the method including: positioning the connector body (22) on the at least partially rounded head (42) of the screw (18); moving the connector body (22) in a downward direction until the at least partially rounded head (42) of the screw (18) is received in the base opening (62); and moving the crown (26) in the downward directiononto the at least partially rounded head (42) of the screw (18) until the at least partially rounded head (42) is received in the first end of the crown (26), wherein moving the crown (26) in the downward direction causes the biasing member (34) to extend at least partially into the support recess opening (86) and engage a slot (126) formed in the second end (118) of the crown (26).

[0092] Example 32. The method of claim 31, wherein moving the crown (26) in the downward direction includes breaking a weld (150) formed between the crown (26) and the connector body (22).

[0093] Example 33. The method of claim 31 or 32, wherein moving the connector body (22) in the downward direction causes the at least partially rounded head (42) of the screw (18) to move a retaining ring (74) positioned in a first groove (66) in the base opening of the connector body (22) into a larger second groove (70) in the base of the connector body (22).

[0094] Example 34. The method according to any of the claims 31-33, further comprising moving the connector body (22) in an upward direction.

[0095] Example 35. The method of claim 34, wherein moving the connector body (22) in the upward direction causes the retaining ring (74) return to the first groove (66) in the connector body (22).

Claims

What is claimed is:

1. A spinal screw assembly (10) comprising: a screw (18) having a threaded body (46) and an at least partially rounded head (42); a connector body (22) having a base (50) and at least two side walls (54, 58) extending from the base (50), the base (50) including a base opening (62) sized to receive the at least partially rounded head (42) of the screw (18), the at least two side walls (54, 58) being spaced apart to form a support recess opening (86) defining a central axis (90); a first bore (98) defined in one of the at least two side walls (54, 58) of the connector body, the first bore (98) extending to the support recess opening (86) along a bore axis (106) transverse to the central axis (90); a crown (26) positioned in the connector body (22) between the base (50) and the support recess opening (86), the crown (26) having a first end (122) sized to receive the at least partially rounded head (42) of the screw (18) and a second end (118) having a slot (126) extending parallel to the central axis (90); and a biasing member (34) positioned in the first bore (98), the biasing member (34) movable along the bore axis (106) between a biased state and an unbiased state, the biasing member (34) being constrained at one end entirely within the first bore (98) by the first end (122) of the crown (26) in the biased state, the one end of the biasing member (34) partially extending into the support recess opening (86) in the unbiased state to engage the slot (126) of the crown (26) to limit axial movement of the crown (26) along the central axis (90).

2. The spinal screw assembly of claim 1, wherein the base opening (62) of the connector body (22) includes a first groove (66), a second groove (70), and a retaining ring (74) moveable between the first groove (66) and the second groove (70), wherein the retaining ring (74) is in a compressed state when the retaining ring (74) is disposed in the first groove (66), wherein the retaining ring (74) is in an extended state when the retainingring (74) is disposed in the second groove (70), and wherein the retaining ring (74) is the sole retaining ring (74).

3. The spinal screw assembly of claim 2, wherein the retaining ring (74) engages the at least partially rounded head (42) of the screw (18), and wherein the retaining ring (74) limits the axial movement of the screw (18) along the central axis (90) in a second direction when the retaining ring (74) is positioned in the first groove (66).

4. The spinal screw assembly according to any of the proceeding claims, further comprising a second biasing member (34) positioned in a second bore (102) in the connector body (22) that is diametrically opposed to the first bore (98).

5. The spinal screw assembly of according to any of the proceeding claims, wherein the biasing member (34) includes a first end cap (134), a second end cap (138), and a spring (142) positioned between the first end cap (134) and the second end cap (138), and wherein the second end cap (138) extends at least partially into the support recess opening (86) in the unbiased state.

6. The spinal screw assembly of claim 5, wherein the first end (122) of the crown (26) is received in the base opening (62) of the connector body (22) when the biasing member (34) is in the unbiased state.

7. The spinal screw assembly according to any of the proceeding claims, further comprising a spot weld (150) between the crown (26) and the base (50) of the connector body (22) when the biasing member (34) is in the biased state.

8. The spinal screw assembly according to any of the proceeding claims, wherein the spot weld (150) allows a controlled break as the biasing member (34) moves from the biased state to the unbiased state.

9. The spinal screw assembly according to any of the proceeding claims, wherein the biasing member (34) limits the axial movement of the crown (26) in a first direction when the biasing member (34) is in the unbiased state.

10. The spinal screw assembly according to any of the proceeding claims, wherein the axial movement of the crown (26) in a second direction along the central axis (90) moves the biasing member (34) from the biased state to the unbiased state.

11. A method of installing a spinal screw assembly (200) for use in a spinal procedure, the spinal screw assembly (10) including, a screw (18) having a threaded body (46) and an at least partially rounded head (42), a connector body (22) having a base (50) and at least two side walls (54, 58) extending from the base (50), the base (50) having a base opening (62), the at least two side walls (54, 58) being spaced apart to form a support recess opening (86) defining a central axis (90), a bore (98) defined in one of the at least two side walls (54, 58) of the connector body (22) and extending into the support recess opening (86), a crown (26) positioned in the connector body (22) and having a first end (122) and a second end (118), and a biasing member (34) positioned in the bore (), the method including: positioning the connector body (22) on the at least partially rounded head (42) of the screw (18); moving the connector body (22) in a downward direction until the at least partially rounded head (42) of the screw (18) is received in the base opening (62); and moving the crown (26) in the downward direction onto the at least partially rounded head (42) of the screw (18) until the at least partially rounded head (42) is received in the first end of the crown (26), wherein moving the crown (26) in the downward direction causes the biasing member (34) to extend at least partially into the support recess opening (86) and engage a slot (126) formed in the second end (118) of the crown (26).

12. The method of claim 11, wherein moving the crown (26) in the downward direction includes breaking a weld (150) formed between the crown (26) and the connector body (22).

13. The method of claim 11 or 12, wherein moving the connector body (22) in the downward direction causes the at least partially rounded head (42) of the screw (18) to move a retaining ring (74) positioned in a first groove (66) in the base opening of the connector body (22) into a larger second groove (70) in the base of the connector body (22).

14. The method according to any of the claims 11-13, further comprising moving the connector body (22) in an upward direction.

15. The method of claim 14, wherein moving the connector body (22) in the upward direction causes the retaining ring (74) return to the first groove (66) in the connector body (22).

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