JP5113524B2 - Bone fixation implant system and method - Google Patents

Description

  The present invention relates to bone arthrodesis, and more particularly to bone fixation implants and systems and methods for attaching such implants.

  Bone arthrodesis or bone fusion is a procedure used to help treat or stabilize damaged bones or joints. In particular, small joint surface fixation is used to fuse the upper and lower small joint surfaces in spine treatment surgery. Prior art systems and methods use bone screws and screw the bone screws into the upper and lower facet surfaces to fix the joints to fuse adjacent bone parts together. Wires are also used to create a ring around the small joint surface to secure the joint. The surgical procedure that must be performed to implant the screw or wire is difficult and time consuming.

  Accordingly, there is a need for improved bone fixation implants, devices and methods.

  An implant for bone arthrodesis consists of a fastener with an elongated shaft having a head at one end and a bone-piercing tip at the opposite end. The first washer has a structure for engaging the head of the shaft so that it can pivot in a multiaxial manner with respect to the head. The locking member has a structure for engaging with the shaft. The locking member has a second washer that is rotatably engaged with the locking member. The shaft and locking member may have cooperating threads. The locking member may be a nut. The second washer may be pivotally attached to the nut by a clip.

  The first washer and the second washer may include an oblique contact surface. The contact surface may have a notch. One of the head and the first washer may have a convex surface. The other of the head and the first washer may have a cooperating concave surface. The convex surface comes into contact with the concave surface and causes a multi-axis rotation of the first washer with respect to the head. The first washer may include a structure for engagement with the bone anchoring device. The structure may comprise a circumferential groove adapted to receive the flange of the bone anchoring device. The first washer may include a rotational engagement structure. The rotational engagement structure may include a recess adapted to receive the projection of the bone anchoring device.

  The locking member may include a structure for engaging the bone anchoring device. The structure may include a recess adapted to receive a protrusion at the lower end portion of the bone anchoring device.

  The bone anchoring device according to the invention may have an elongated cannula with a collet for removably engaging the first washer and for advancing the first washer. The bone anchoring device may further include a structure for removably engaging the fastener and for advancing the fastener through the collet and through the first washer. A lower end portion extends from the cannula. The lower end portion preferably has a structure for detachably engaging with the locking member. The fastener, the first washer, and the locking member are aligned so that the advancing fastener is advanced through the first washer, the bone, and the second washer into the locking member. Is done.

  A system for performing bone fixation includes an implant for bone fixation and a bone fixation device. The implant includes an elongated shaft having a head at one end and a bone piercing tip at the opposite end. The first washer has a structure for engaging the head of the shaft so that it can pivot in a multiaxial manner with respect to the head. The locking member has a structure for engaging with the shaft. The locking member may have a second washer that is rotatably engaged with the locking member. The bone fixation device may include an elongated cannula with a collet for removably engaging the first washer and for advancing the first washer. A structure is provided for removably engaging the fastener and for advancing the fastener in the collet and in the first washer. The bone fixation device further includes a lower end portion extending from the cannula. The lower end portion has a structure for detachably engaging with the locking member. The fastener, the first washer, and the locking member cause the advancing fastener to advance through the first washer, into the bone, and through the second washer into the locking member. To be consistent.

  A method for performing bone fixation includes a fastener having an elongated shaft having a head at one end and a bone-piercing tip at the opposite end, and a shaft that is pivotable relative to the head. Providing an implant for bone fixation including a first washer having a structure for engaging a head and a locking member having a structure for engaging a shaft. The locking member may have a second washer that is pivotally engaged with the locking member.

  The method further includes providing a bone anchoring device, wherein the bone anchoring device is associated with an elongate cannula having a collet for removably engaging the first washer and for advancing the washer, and the fastener. And a structure for advancing the fastener through the collet, the first washer, and a structure extending from the cannula and removably engaged with the locking member. A lower end portion. The fastener, the first washer, and the locking member are advanced into the locking member as the advancing fastener advances in the first washer, the bone, and the second washer.

  The method further includes positioning the bone fixation device such that the bone is positioned between the cannula and the lower end portion. Actuating the bone anchoring device advances the first washer to the bone. The bone anchoring device is then actuated to advance the fastener into the first washer, through the bone, and into the locking member.

  A bone anchoring device 10 according to the present invention is shown in FIG. The bone anchoring device 10 has a main body 12 and an elongated housing 14 that terminates in a lower end portion 16. The bone anchoring device 10 has a structure for holding the first washer 20 at the distal end of the elongate housing 14 and holding the second washer 24 and the locking member 28 at the lower end portion 16. A handle 30 may be provided for grasping the bone fixation device 10 and triggers 34 and 38 may be provided for operating the bone fixation device 10 during the implant procedure. A guide knob 35 is actuated to turn the housing 14 and the attached lower end portion 16 in order to properly place the second washer 24. A locking lever 32 may be provided to lock the bone anchoring device 10 to the bone after the first washer 20 and the second washer 24 are correctly positioned. The locking lever 32 may be unlocked to allow repositioning of the first washer 20 and the second washer 24. A knob 37 may be provided for manually advancing the fastener and applying an appropriate torque.

  A slidable protective cannula or sheath 39 may be used to facilitate insertion into the body and cover the lower end portion 16. In FIG. 1a, a bone anchoring device 10 is shown having a protective cannula or sleeve 39 for shielding the housing 14 and lower end portion 16 during the insertion process. A grip 41 can be used to pull back the cannula 39 before use. The housing 14, the lower end portion 16 and the guide knob 35 are preferably removable from the main body 12. Another housing 14, lower end portion 16 and guide knob 35 may be attached for reuse of the main body portion 12 with another implant.

  The implant 40 is shown in FIG. The implant 40 comprises a fastener having an elongated shaft 44 and a head 48. The fastener engages with the first washer 20, the second washer 24, and the locking member 28. As shown in FIG. 3, the head 48 may have a convex surface 54 for use in engaging the first washer 20, as will be described below. A thread 58 is provided on the shaft 44 for engaging the locking member 28. Other engagement structures are possible. A tip 62 is provided for penetrating the bone during the implant procedure. Grooves or flutes 66 provide space for bone chips to disperse during insertion into the locking member 28 and carry bone debris away from the apex 62 as the tip is advanced through the bone. Appropriate structures, such as hexagonal openings 70, are provided for engagement of fasteners 44 that provide compressive and rotational forces during the implant procedure. A recess or other suitable structure may be provided to allow the fixation device to grip the head 48.

  The second washer 24 and the locking member 28 are shown in FIGS. The second washer 24 may have a suitable structure such as a serration 80 for engaging the bone surface. Variations of the structure are possible. The second washer 24 rotates with respect to the locking member 28. The locking member 28 may have a suitable structure such as an opening 84. A cooperating engagement structure such as a clip 88 is provided for engaging the opening 84 through the opening 89 in the second washer 24 so that the second washer 24 engages the locking member 28. It is done. The convex surface 92 of the locking member 28 may cooperate with a similar concave surface 96 of the second washer 24. The clip 88 may be placed in a suitable retaining groove 90 of the second washer 24. To secure the locking member 28 to the lower end portion 16 of the bone anchoring device 10, an opening 104 and a slotted L-shaped groove 108 are provided for engaging a corresponding protrusion on the lower end portion 16.

  The first washer 20 is shown in FIGS. The first washer 20 may have a concave surface 114 for cooperating with the convex surface 54 of the head 48 of the fastener 44. An elongated opening 118 may be in the form of a tapered slot and allows rotation of the first washer 20 relative to the fastener 44. The first washer 20 may have a structure for engaging the washer by the bone anchoring device 10. This structure may be a circumferential groove 124 and the circumferential groove 124 may be engaged by a cooperating flange structure of the bone anchoring device 10. As a result, the first washer 20 is advanced toward the surface of the bone. Additional structures such as recesses 130 may be provided for engagement by the bone anchoring device 10 to allow rotation of the first washer 20. This helps to place the first washer 20 correctly. The first washer 20 may have an inclined contact surface 136 that causes the first washer 20 to cooperate with a bone surface such as a small articular surface that is at a considerable angle. Additional structures may be provided to facilitate engagement. The structure may include serrations 140 on the contact surface 136. The opening 118 should expand further like a longitudinal groove toward the contact surface 136 to allow greater rotation.

  The method of engagement among the fastener 44, the first washer 20, the second washer 24, and the locking member 28 is shown in FIGS. The rotational movement of the first washer 20 is shown. The first washer 20 is preferably inclined about 30 ° from a cross section passing through the screw shaft. To some extent, it is possible depending on the bone tissue to be fused. The second washer 24 can be tilted from + 45 ° to −20 ° from the cross section with the screw shaft. It is possible to some extent.

  A suitable structure for engaging the first washer 20 may be provided in the bone anchoring device 10. Although a collet 140 is shown in FIG. 13, other holding structures are possible. The collet has a distal annular flange 144 that engages the groove 124 of the first washer. In order to allow the first washer 20 to rotate, a projection 148 is provided for engaging the recess 130. A plate for the elongate slot 152 to spring the lower lip 144 so that the collet 140 can be engaged and disengaged from the first washer with a moderate manual force. Spring 153 is made.

  A method for engaging the first washer 20 and the second washer 24 with the bone is shown in FIGS. The locking member 28 is engaged with the lower end portion 16 by a suitable slot. The protrusion of the lower end portion 16 can be engaged with the opening 104 of the locking member 28. Bone is shown schematically as an upper minor joint surface 160 and a lower minor joint surface 164. The first washer 20 is engaged with the collet 140. The lower end portion 16 is arranged so that the second washer 24 faces the lower minor joint surface 164. By rotating the lower washer (second washer) 24 with respect to the locking member 28 and the lower end portion 16, the second washer 24 is made to coincide with the inclined portion 168 of the lower small joint surface 164. When the collet 140 is then lowered, the first washer 20 engages the inclined portion 172 of the upper small joint surface 160. When the protrusion 148 engages the recess 130, the rotation of the collet 140 rotates the first washer 20 and correctly places the first washer 20 relative to the inclined portion 172 of the upper small joint surface 160.

  Attachment of the fastener 44 is shown in the sequence of FIGS. The fastener 44 is held by a suitable engagement portion (not shown) of the bone anchoring device 10 and driven toward the upper minor joint surface 160. The head 48 can be rotated to engage the fastener 44 so that the tip 62 can be driven into the upper minor joint surface 160. The apex 62 may be provided with a longitudinal groove to remove bone fragments when the fastener 44 is rotated and pushed into the bone. In this way, the fastener 44 pierces the upper minor joint surface 160 and the lower minor joint surface 164. The fastener 44 engages the locking member 28 as the fastener 44 is advanced through the bone. The screw thread 58 is screwed into the female screw thread of the locking member 28. Thereby, as shown in FIG. 19, the fastener 44 is engaged with the locking member 28. Then, as shown in FIGS. 20 and 21, the collet 140 can be removed. As shown in FIG. 22, when the bone anchoring device 10 is removed, the lower end portion 16 is removed. This results in a complete implant across the upper minor joint surface 160 and the lower minor joint surface 164, as shown in FIG.

  A bone anchoring device 10 used during the implant procedure is shown in FIGS. The bone anchoring device 10 has an elongated housing 14 in the general shape of a cannula. A collet 140 is provided in the housing 14. The collet 140 has a structure for engaging with the first washer 20. Although any configuration is possible, the collet 140 of FIG. 24 has an inwardly directed circumferential retaining flange 144. The circumferential holding flange 144 engages with the groove 124 of the first washer 20. The collet 140 may further have a protrusion 148 that engages the recess 130 of the first washer 20. Thereby, the first washer 20 is held so as not to move out of the collet 140 and to rotate with respect to the collet 140. The spring force that holds the first washer 20 on the collet 140 is such that manual force can be used to remove the collet 140 from the first washer 20 after the first washer 20 is secured to the bone. It is.

  The collet 140 is attached to the housing 14 so that the collet 140 can move axially in the housing 14. The collet 140 may have a structure for slidably engaging the guide groove 222 or other suitable structure. The first trigger 34 can be operated to move the collet 140 and the first washer 20 through the housing 14 from the position shown in FIG. 24 to the position shown in FIG. When the gear 230 is rotated, the shaft 210 is withdrawn by the threaded end 246 of the shaft. The first washer 20 is seated on the upper minor joint surface 160, and the second washer 24 is seated on the lower minor joint surface 164. If the direction is not correct, the guide washer 35 can be rotated to correctly place the second washer 24. The locking lever 32 can be actuated to fix the bone anchoring device 10 to the small joint surface.

  Then, the action of the trigger 38 rotates the helical gear 230, whereby the helical gear 230 rotates the normally slidable hexagonal or flat chamfered shaft 210. This causes the extension threaded end 246 of the shaft to rotate and threadably engage with the female thread 250 on the inner surface of the collet 140. The face of the threaded end 246 includes a structure for engaging the fastener 44, such as a hexagonal tip. Thereby, rotation of threaded end 246 causes fastener 44 to rotate and advance. The fastener 44 advances through the first washer 20 and advances through the upper small joint surface 160 and the lower small joint surface 164 by a punching action caused by the advancement and rotational movement of the fastener 44. The fastener 44 then advances through the second washer 24 and into the locking member 28. The thread 58 of the fastener 44 is screwed with the corresponding thread on the inner surface of the locking member 28. The knob 37 can then be actuated to properly torque the implant 40 to fully attach the locking member 28 to the fastener 44.

  The present invention provides many advantages over prior art pedicle screw fixation systems. There are internal threads that increase the stress in the bone when the osteosynthesis, such as the upper and lower facets 160 and 164, is squeezed between the first washer 20 and the second washer 24. It does not exist in bones. The threads 58 are only at the lower end of the shaft 44 so that these threads engage only the locking member 28 and do not apply thread stress to the interior of the bone. Also, a conventional torque mechanism can be applied so that a known compressive force is applied to the joint when the implant is tightened using a rotational force. The first washer 20 and the second washer 24 can be provided with various inclined contact surfaces that are each adapted to different bone shapes for joining bone portions other than the small joint surfaces. Further, the amount of inclination of the first washer 20 and the second washer 24 with respect to the fastener 44 can be adjusted according to the specific bone shape to be joined by the allowable rotation and multiaxial movement. The attachment of the implant 40 is reversible. The compression of the implant washers 20 and 24 can be removed to allow repositioning prior to insertion of the fastener 44. Thus, the present invention provides great variability and adaptability in addition to ease of installation, control and single penetration.

  The various components of the present invention are constructed of surgical plastic or metal structures such as titanium. Different dimensions and shapes of the various components of the present invention are within the scope of the invention.

  The present invention may be embodied in other forms without departing from its spirit or essential characteristics, and therefore, reference should be made to the appended claims rather than the foregoing specification to indicate the scope of the invention. Should.

1 is a perspective view of a bone anchoring device according to the present invention. 1 is a perspective view of a bone anchoring device having a protective cannula. 1 is a side view of a bone and joint fixation implant according to the present invention. FIG. It is a side view of a fastener. It is a perspective view. It is a side view of a fastening member and a washer assembly. It is a perspective view. It is the perspective view partially seen through. It is a perspective view of the 1st outer surface washer. It is a bottom perspective view. It is a bottom perspective view of a modified embodiment. It is the bottom perspective view partially excised. FIG. 6 is a partially cut away sectional view showing another orientation. FIG. 5 is a partially cut away cross-sectional view showing a deformed orientation. FIG. 6 is a partially cut away sectional view showing another orientation. It is a perspective view of a collet. It is a schematic side view which shows a 1st operation mode. It is a schematic side view which shows a 2nd operation mode. FIG. 3 is a schematic side view partially cut away and partially sectioned. It is the schematic perspective view partially excised. It is a schematic perspective view of a 2nd operation mode. FIG. 6 is a partially schematic virtual perspective view of a subsequent operation mode. It is a schematic perspective view of other operation modes. It is a schematic sectional drawing. It is a schematic sectional drawing which shows final attachment. 1 is a schematic perspective view showing bone fixation using an implant according to the present invention. FIG. 1 is a schematic cross-sectional view showing a bone fixation system and method in a first mode of operation. It is a schematic sectional drawing which shows a 2nd operation mode. It is a schematic sectional drawing which shows a 3rd operation mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bone fixing device 12 Main body 14 Housing 16 Lower end part 20 1st washer 24 2nd washer 28 Locking member 30 Handle 32 Locking lever 34 Trigger 35 Guide knob 37 Knob 38 Trigger

Claims (14)

A fastener with an elongated shaft having a head at one end and a bone-piercing tip at the opposite end;
A first washer having a structure for engaging the head of the shaft so that it can pivot in a multiaxial manner with respect to the head;
A locking member having a structure for engaging with the shaft, and the locking member has a second washer rotatably engaged with the locking member;
The elongate shaft is configured to extend through both the first washer and the second washer to engage the locking member;
The first washer is configured to engage with the convex surface or concave surface of the head of the shaft, and the second washer is configured to engage with the concave surface or convex surface of the locking member. Yes,
Implant for bone joint fixation.   The implant of claim 1, wherein the shaft and the locking member include cooperating threads.   The implant according to claim 2, wherein the locking member includes a nut.   The implant according to claim 3, wherein the second washer is rotatably attached to the nut by a clip.   The implant of claim 1, wherein the first washer and the second washer include angled contact surfaces.   The implant of claim 1, wherein the first washer and the second washer include a contact surface having a knurled surface.   One of the head and the first washer has a convex surface, the other of the head and the first washer has a cooperating concave surface, and the convex surface is in contact with the concave surface. The implant of claim 1, wherein the implant provides multi-axial rotation of the first washer with respect to the head.   The implant of claim 1, wherein the first washer includes a structure for engagement with a bone fixation device.   The implant of claim 8, wherein the structure for engaging a bone fixation device includes a circumferential groove.   The implant of claim 8, wherein the first washer further comprises a rotational engagement structure.   The implant of claim 10, wherein the rotational engagement structure includes at least one recess adapted to receive at least one protrusion of a bone anchoring device.   The implant of claim 1, wherein the locking member includes a structure for engaging a bone anchoring device.   The implant of claim 12, wherein the engagement structure of the locking member includes at least one recess adapted to receive at least one protrusion of the bone anchoring device.   The first washer has a tapered slot therein, the elongated shaft of the first washer and the tapered slot being a cooperating surface that provides rotation of the first washer with respect to the elongated shaft. The implant of claim 1 having:

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