PEDICLE SCREW REMOVAL TOOL AND METHOD OF USE

Abstract

Disclosed is a universal pedicle screw removal tool comprising a tapered shaft having an L shaped tip on one end and a generally square head on an opposite end. A lower section leads to a tapered section which is connected to a handle. The handle may include a set of serrations to provide increased grip. The handle is connected to the head. The tip is sized to engage the channel of a tuliped pedicle screw while the head is sized to engage a ratchet or other torque producing tool. In an alternate embodiment, the tip is T shaped. In another alternate embodiment, the handle section includes opposing members extending from the shaft to form a T shaped handle. In use, the tip is inserted into the channel of a tuliped pedicle screw while the shaft is rotated to unscrew the pedicle screw from a patient's bone.

Claims

1. A tool for the removal of a tuliped pedicle screw, the tuliped pedicle screw having a first longitudinal axis and a channel, the channel defined by a first blade and a second blade, the tool comprising: an unbendable generally cylindrical shaft, having a second longitudinal axis; a tip, fixed to the shaft, having a first prong extending generally perpendicularly from the shaft for placement in the channel adjacent the first blade and the second blade with the second longitudinal axis coplanar with the first longitudinal axis; and, a tool connector head, fixed to the shaft, opposite the tip.

2. The tool of claim 1 wherein: the tool connector head further comprises a square cross section, the square cross section having a dimension of between about inch to about inch across; and, the first prong has a diameter of between about inch and about inch.

3. The tool of claim 1 wherein the shaft further includes an offset angle section, between the tip and the tool connector head, for centering the first prong with respect to the second longitudinal axis.

4. The tool of claim 1 wherein: the tip includes a second prong, extending generally perpendicular from the shaft; and, the second prong is axially aligned with the first prong.

5. The tool of claim 1 further comprising a torque imposing tool affixed to the tool connector head.

6. A method of removing a tuliped pedicle screw, the tuliped pedicle screw having a first longitudinal axis and a channel, the channel defined by a first blade and a second blade, the method comprising: providing a tool having an off axis angular tip rigidly connected to an unbendable shaft, the shaft having a second longitudinal axis; engaging the off axis angular tip with the channel; positioning the first longitudinal axis and the second longitudinal axis in a generally coplanar relationship; and, rotating the shaft axially to apply a rotational force to the first blade and the second blade to remove the tuliped pedicle screw.

7. The method of claim 6 further comprising: securing the tip to the tuliped pedicle screw with an end cap.

8. The method of claim 6 further comprising: Providing the shaft with an angular section for positioning the off axis angular tip into coaxial alignment with the first longitudinal axis; and, positioning the first longitudinal axis and the second longitudinal axis in a generally collinear relationship.

9. The method of claim 8 further comprising: rotating the shaft about one of the group of the first longitudinal axis and the second longitudinal axis.

10. The method of claim 6, further comprising: providing the off axis angular tip with a first prong extending generally perpendicularly from the shaft and a second prong extending generally perpendicularly from the shaft; engaging the channel with one of the first prong and the second prong; and, positioning the first longitudinal axis and the second longitudinal in one of a coaxial relationship and the coplanar relationship.

11. The method of claim 10 further comprising: rotating the shaft about one of the first longitudinal axis and the second longitudinal axis.

12. The method of claim 6 further comprising: providing the shaft with a set of rigid opposing torque imposing members radially extending from the shaft; and, rotating the shaft by applying a rotational force to the rigid opposing torque imposing members.

13. The method of claim 6 further comprising: providing the shaft with a tool connection head axially connected to the shaft; connecting a torque imposing tool to the tool connection head; and, rotating the shaft by applying a rotational force to the torque imposing tool.

14. The method of claim 13 further comprising the step of: providing a ratchet as the torque imposing tool.

15. The method of claim 6 further comprising the step of: adjusting a tool trajectory to disalign the first longitudinal axis and the second longitudinal axis.

16. A pedicle screw removal tool for removing a tuliped pedicle screw, the tuliped pedicle screw having a first longitudinal axis and a transverse channel, the tool comprising: a rigid shaft having a second longitudinal axis; a tool connection head, coaxial with the second longitudinal axis, connected to the shaft; a first prong means for engagement with the channel, extending from the shaft, generally perpendicularly to the second longitudinal axis; and, wherein the first longitudinal axis is coplanar with the second longitudinal axis.

17. The pedicle screw removal tool of claim 16 wherein the shaft further comprises: an angled section extending at an acute angle with respect to the second longitudinal axis; and, the first prong positioned to intersect the second longitudinal axis.

18. The pedicle screw removal tool of claim 16 further comprising: a second prong means, for engagement with the channel, extending generally perpendicularly from the shaft, and coaxial with the first prong means; and, wherein the second longitudinal axis is axially aligned with the first longitudinal axis.

19. The pedicle screw removal tool of claim 16 further comprising: a first torque imposing member extending generally perpendicularly from the shaft; a second torque imposing member extending generally perpendicularly from the shaft; and, wherein the first member and the second member are generally coaxial.

20. The pedicle screw removal tool of claim 16 further comprising: a flexible polymeric grip surrounding the shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is an isometric view of vertebrae anchored by pedicle screws and stability rods as known in the prior art.

[0016] FIG. 2A is an isometric view of a tuliped pedicle screw as known in the prior art.

[0017] FIG. 2B is an exploded isometric view of a tuliped pedicle screw engaged with a stability rod as known in the prior art.

[0018] FIG. 3A is an isometric view of a preferred embodiment.

[0019] FIG. 3B is a side view of the preferred embodiment of FIG. 3A.

[0020] FIG. 4A is an isometric view of the preferred embodiment of FIG. 3A positioned so that the longitudinal axis of the screw is coplanar with the longitudinal axis of the tool.

[0021] FIG. 4B is an isometric view of the preferred embodiment of FIG. 3A engaged with a tuliped pedicle screw.

[0022] FIG. 4C is a flowchart of a preferred method of using the tool.

[0023] FIG. 5 is a side view of an alternate preferred embodiment.

[0024] FIG. 6 is a side view of an alternate preferred embodiment.

[0025] FIG. 7 is a side view of an alternate preferred embodiment.

[0026] FIG. 8 is a side view of an alternate preferred embodiment.

[0027] FIG. 9 is a side view of an alternate preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0028] In the description that follows, like parts are marked throughout the specification and figures with the same numerals, respectively. The figures are not necessarily drawn to scale and may be shown in exaggerated or generalized form in the interest of clarity and conciseness.

[0029] Referring to FIGS. 3A and 3B, pedicle screw removal tool 300 is a generally tapered cylindrical shaft comprising lower section 302 integrally formed with neck 304. Neck 304 is integrally formed with handle 306. Tip 308 is integrally formed with lower section 302 opposite neck 304. Head 310 is integrally formed with handle 306 opposite neck 304. Torque imposing tool 313 is removably attached to the head. The torque imposing tool may be, for example, a ratchet adaptor which applies torque in only one rotational direction. In another example, the torque imposing tool can be a simple crescent wrench. In yet another example, the torque imposing tool can be a torque wrench indicating the amount of torque applied to prevent shearing of the pedicle screw shaft. Lower section 302 is axially aligned with neck 304. Neck 304 is axially aligned with handle 306. Handle 306 is axially aligned with head 310. Lower section 302, neck 304, handle 306, and head 310 all share central longitudinal axis 312. Tip 308 is generally L shaped formed by prong 314. Prong 314 extends from tip 308 generally perpendicular to lower section 302. In a preferred embodiment, pedicle screw removal tool 300 is constructed of surgical grade stainless steel.

[0030] The overall length of pedicle screw removal tool 300 can range from approximately eight to twelve inches depending on desired use. Prong 314 generally ranges from to inch in diameter. All dimensions are provided with a 5% tolerance. The length of prong 314 ranges from approximately to one inch. Lower section 302 ranges in length from approximately three to five inches. Lower section 302 generally ranges from to inch in diameter. The length of neck 304 ranges from approximately one to two inches. Neck 304 is a generally frustoconical shape with an increasing diameter from a range of to inch in diameter at the connection of neck 304 to lower section 302 to a range of inch to inch in diameter at the connection of neck 304 to handle 306. Handle 306 ranges in length from approximately three to four inches. Handle 306 generally ranges from to inch in diameter. In an alternate embodiment, handle 306 may include serrations 316. Head 310 ranges in length from approximately to one inch. Head 310 has a generally square cross-section width a width that ranges from approximately to of an inch. In alternate embodiments, head 310 may have other polygonal cross-sectional shapes suitable for attachment of the torque imposing tool.

[0031] Referring to FIGS. 4A and 4B, a method of using pedicle screw removal tool 300 to remove a tuliped pedicle screw will be further described.

[0032] At step 450, residual tissue is cleared from the end cap from the pedicle screw. At step 452, end cap 216 is removed using the appropriate spanner, if possible. In cases of advanced bone growth, the cap may remain in place in the screw. However, preferably the cap is at least loosed sufficiently to dislodge and remove the stability rod. At step 454, stability rod 222 is removed. At step 456, remaining tissue surrounding body 204 of pedicle screw 200 is then removed. At step 458, tip 308 is inserted into channel 206 such that prong 314 is adjacent blades 208 and 210. At step 460, longitudinal axis 312 of pedicle screw removal tool 300 is positioned generally coplanar and parallel with longitudinal axis 226 of threaded section 202. Longitudinal axis 312 of pedicle screw removal tool 300 is generally positioned offset from longitudinal axis 226 of threaded section 202 such that the axes are not axially aligned. At step 462, end cap 216 is reengaged with body 204 to secure tip 308 to pedicle screw 200. Optionally, end cap 216 remains disengaged from body 204. In the event that end cap 216 is compromised and cannot be removed, tip 308 is inserted into channel 206 from the side and underneath end cap 216. At step 464, pedicle screw removal tool 300 is rotated in direction 228 around pedicle screw 200, generally counter-clockwise, to unscrew pedicle screw 200 from the bone. Rotation of pedicle screw removal tool 300 can be accomplished by use of handle 306 or, if necessary, a torque producing tool such as a ratchet attached to head 310. Motorized torque producing tools may also be employed. At step 466, the trajectory of the tool may optionally be adjusted to a different angle by loosening the end cap, realigning the axis of the tool with respect to the screw and retightening the end cap.

[0033] Use of pedicle screw removal tool 300 eliminates the need to locate a matching removal tool for the pedicle screw regardless of whether or not the socket has been compromised. This procedure improves the speed and accuracy of pedicle screw removal as time is not wasted locating the proper sized tool, or fabricating custom tools. Further, safety is improved by reducing time required attending to unnecessary tissue damage and contamination.

[0034] Referring to FIG. 5, an alternate embodiment will be described. Pedicle screw removal tool 500 is a generally cylindrical shaft comprising lower section 502 integrally formed with and connected to neck 504. Neck 504 is integrally formed with and connected to handle 106. Neck 504 radially expands from lower section 502 to handle 506. Tip 508 is integrally formed with and connected to lower section 502 opposite neck 504. Head 510 is integrally formed with and connected to handle 506 opposite neck 504. Lower section 502 is axially aligned with neck 504. Neck 504 is axially aligned with handle 506. Handle 506 is axially aligned with head 510. Lower section 502, neck 504, handle 506, and head 510 all share central longitudinal axis 512. Handle 506 further includes opposing members 514 and 515. Tip 508 is generally L shaped formed by prong 516. Prong 516 extends from tip 508 generally perpendicular to lower section 502. In a preferred embodiment, pedicle screw removal tool 500 is constructed of surgical grade steel.

[0035] The overall length of pedicle screw removal tool 500 can range from approximately eight to twelve inches depending on desired use. Prong 516 generally ranges from to inch in diameter. The length of prong 516 ranges from approximately to one inch. Lower section 502 ranges in length from approximately three to five inches. Lower section 502 generally ranges from to inch in diameter. The length of neck 504 ranges from approximately one to two inches. Neck 504 is a generally frustoconical shape with an increasing diameter from a range of to inch in diameter at the connection of neck 504 to lower section 502 to a range of inch to inch in diameter at the connection of neck 504 to handle 506. Handle 506 ranges in length from approximately three to four inches. Handle 506 generally ranges from to inch in diameter. Members 514 and 515 are generally cylindrical (however, other cross-sections are envisioned), are axially aligned, and extend from handle 506 generally perpendicular to handle 506. Members 514 and 515 each range in length from approximately one and to two inches. Members 514 and 515 generally range from to inch in diameter. Head 510 ranges in length from approximately to one inch. Head 510 has a generally square cross-section width a width that ranges from approximately to of an inch. In alternate embodiments, head 510 may have other polygonal cross-sectional shapes suitable for attachment of a torque producing tool.

[0036] In use, in addition to the previous methods discussed, members 514 and 515 may be used to assist in the rotation of pedicle screw removal tool 500 in order to remove tuliped pedicle screws.

[0037] Referring to FIG. 6, an alternate embodiment will be described. Pedicle screw removal tool 600 is a generally tapered cylindrical shaft comprising an angled lower section 602 integrally formed with neck 604. Neck 604 is integrally formed with handle 606. Tip 608 is integrally formed with lower section 602 opposite neck 604. Head 610 is integrally formed with handle 606 opposite neck 604. Lower section 302 extends at angle 614 from neck 604. Neck 604 is axially aligned with handle 606. Handle 606 is axially aligned with head 610. Neck 604, handle 606, and head 610 all share central longitudinal axis 612. Tip 608 is generally L shaped formed by prong 616. Prong 616 extends from tip 608 generally perpendicular to longitudinal axis 612. Longitudinal axis 612 intersects prong 616. In a preferred embodiment, pedicle screw removal tool 600 is constructed of surgical grade stainless steel.

[0038] The overall length of pedicle screw removal tool 600 can range from approximately eight to twelve inches depending on desired use. Prong 616 generally ranges from to inch in diameter. The length of prong 616 ranges from approximately to one inch. Lower section 602 ranges in length from approximately three to five inches. Lower section 602 generally ranges from to inch in diameter. Angle 614 ranges from approximately 15 to 45. The length of neck 604 ranges from approximately one to two inches. Neck 604 is a generally frustoconical shape with an increasing diameter from a range of to inch in diameter at the connection of neck 604 to lower section 602 to a range of inch to inch in diameter at the connection of neck 604 to handle 606. Handle 606 ranges in length from approximately three to four inches. Handle 606 generally ranges from to inch in diameter. Head 610 ranges in length from approximately to one inch. Head 610 has a generally square cross-section width a width that ranges from approximately to of an inch. In alternate embodiments, head 610 may have other polygonal cross-sectional shapes suitable for attachment of a torque producing tool.

[0039] Referring to FIG. 7, an alternate embodiment will be described. Pedicle screw removal tool 700 is a generally tapered cylindrical shaft comprising lower section 702 integrally formed with and connected to neck 704. Neck 704 is integrally formed with and connected to handle 706. Tip 708 is integrally formed with and connected to lower section 702 opposite neck 704. Head 710 is integrally formed with and connected to handle 706 opposite neck 704. Lower section 702 is axially aligned with neck 704. Neck 704 is axially aligned with handle 706. Handle 706 is axially aligned with head 710. Lower section 702, neck 704, handle 706, and head 710 all share longitudinal axis 712. Tip 708 is generally T shaped formed by prongs 714 and 715. Prongs 714 and 715 are axially aligned and extend from tip 708 generally perpendicular to lower section 702. The twin prongs of pedicle screw removal tool 700 are important in cases where access to the screw channel is obstructed from one side or the other. In these cases, either prong may be used in the channel to remove the screw. In a preferred embodiment, pedicle screw removal tool 700 is constructed of surgical grade stainless steel.

[0040] The overall length of pedicle screw removal tool 700 can range from approximately eight to twelve inches depending on intended use. Prong 714 and 715 generally range from to inch in diameter. The length of each prong 714 and 715 ranges from approximately to inch. Lower section 702 ranges in length from approximately three to five inches. Lower section 702 generally ranges from to inch in diameter. The length of neck 704 ranges from approximately one to two inches. Neck 704 generally expands from a range of to inch in diameter at the connection of neck 704 to lower section 702 to a range of inch to inch in diameter at the connection of neck 704 to handle 706. Handle 706 ranges in length from approximately three to four inches. Handle 706 generally ranges from to inch in diameter. Head 710 ranges in length from approximately to 1 inch. Head 710 has a generally square cross-section width a width that ranges from approximately to of an inch. In alternate embodiments, head 710 may have other polygonal cross-sectional shapes suitable for attachment of a torque producing tool.

[0041] Referring to FIG. 8, an alternate embodiment will be described. Pedicle screw removal tool 800 is a generally tapered cylindrical shaft comprising a offset lower section 802 integrally formed with neck 804. Neck 804 is integrally formed with handle 806. Tip 808 is integrally formed with lower section 802 opposite neck 804. Head 810 is integrally formed with handle 806 opposite neck 804. Neck 804 is axially aligned with handle 806. Handle 806 is axially aligned with head 810. Neck 804, handle 806, and head 810 all share central longitudinal axis 812. Lower section 802 comprises segments 818 and 820. Segment 818 is generally parallel with longitudinal axis 812 and connects segment 820 to tip 808. Segment 820 extends generally perpendicular to longitudinal axis 812 from neck 804. Prong 816 extends from segment 818 generally perpendicular to longitudinal axis 812. Longitudinal axis 812 intersects prong 816. In a preferred embodiment, pedicle screw removal tool 800 is constructed of surgical grade stainless steel.

[0042] The overall length of pedicle screw removal tool 800 can range from approximately eight to twelve inches depending on desired use. The length of prong 816 ranges from approximately to 1 inch. Prong 816 generally ranges from to inch in diameter. Lower section 802 ranges in length from approximately three to five inches. Lower section 802 generally ranges from to inch in diameter. Segment 820 ranges in length from approximately to 1 inch. Segment 820 generally ranges from to inch in diameter. The length of neck 804 ranges from approximately one to two inches. Neck 804 is a generally frustoconical shape with an increasing diameter from a range of to inch in diameter at the connection of neck 804 to lower section 802 to a range of inch to inch in diameter at the connection of neck 804 to handle 806. Handle 806 ranges in length from approximately three to four inches. Handle 806 generally ranges from to inch in diameter. Head 810 ranges in length from approximately to 1 inch. Head 810 has a generally square cross-section width a width that ranges from approximately to of an inch. In alternate embodiments, head 810 may have other polygonal cross-sectional shapes suitable for attachment of a torque producing tool.

[0043] Referring to FIG. 9, an alternate embodiment will be described. Pedicle screw removal tool 900 is generally a cylindrical shaft comprising lower section 902 integrally formed with and connected to center section 909 and neck 904. Tip 908 is integrally formed with and connected to lower section 902 opposite neck 904. Lower section 902 is axially aligned with neck 904. Neck 904 is generally of a larger diameter than lower section 902. The diameter of the tool is reduced gradually within the handle along center section 909, which is frustoconical in shape. Neck 904 is axially aligned with handle 906. Handle 906 is axially aligned with head 910. In a preferred embodiment, head 910 is a/4 inch square cross section adapted to fit a ratchet drive. Annular indention 911 is positioned adjacent and distal to head 910. In a preferred embodiment, annular indention 911 and head 910 are adapted to fit an AO connect handle or a T-handle as known in the art.

[0044] In a preferred embodiment, handle 906 is comprised of angular end stop 905 connected to convex center section 950 and angular end stop 907. Handle 906, in a preferred embodiment, is integrally formed of a nitrile rubber, a polyethylene plastic, or a Teflon material, inductively welded to the tool to prevent movement of the handle with respect to center section 909. Other medical grade pliable rubber or pliable plastic materials can be used. Handle 906 is generally cylindrical and surrounds the tool having a common axis in a common central axis with the tool. Lower section 902, neck 904, handle 906 and head 910 all share longitudinal axis 912. Tip 908 is generally L-shaped including prong 916. Prong 916 extends from lower section 902 generally perpendicular to longitudinal axis 912. Longitudinal axis 912 intersects the axis of prong 916 intersects axis 913 of prong 916. In a preferred embodiment, pedicle screw removal tool 900 is constructed of surgical grade stainless steel, with dimensions similar to those previously described.

[0045] Pedicle screw removal tools 600, 700, 800 and 900 can each be used to remove any size tuliped pedicle screw.

[0046] In use, end cap 216 is removed. Rod 222 is removed. Tissue surrounding body 204 of the pedicle screw is removed. When using tool 600, tip 608 is inserted into channel 206 such that prong 616 is adjacent blades 208 and 210. When using tool 700, tip 708 is inserted into channel 206 such that prongs 714 and 715 are adjacent blades 208 and 210. When using pedicle screw removal tool 800, tip 808 is inserted into channel 206 such that prong 816 is adjacent blades 208 and 210. In the case of tools 600, 700 and 800, longitudinal axis 612, 712, or 812 is positioned generally coaxial with longitudinal axis 226 of threaded section 202. The pedicle screw removal tool is rotated, generally counter-clockwise, to dislodge pedicle screw 200 from its attachment to the bone. Rotation of the pedicle screw removal tool can be accomplished by hand using the handle or, if necessary, a torque producing tool such as a wrench or ratchet can be attached to the head.

[0047] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this disclosure is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present disclosure as defined by the appended claims.