Bone fixation implant system and method

The present invention relates to bone joint fixation, in particular to bone fixation implants, and systems and methods for attaching such implants.

Bone joint fixation or fusion is a procedure used to aid in the treatment or stabilization of damaged bone or joints. In particular, small joint surface fixation is used to fuse the upper small joint surface and the lower small joint surface in spinal surgery. Prior art systems and methods use bone screws that are screwed into the upper and lower articular surfaces to secure the joint so that adjacent bone portions fuse together. Wires are also used to form loops around the articular surface to secure the joint. The surgical procedure that must be performed to implant a screw or wire is difficult and time consuming.

<p> Therefore, there is a need for improved bone fixation implants, devices and methods.</p>

<p> Implants for osteoarthritis consist of fasteners with an elongated shaft with a head at one end and a piercing tip at the opposite end. The first washer has a structure for engaging the head of the shaft so that it can rotate multiaxially 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 is preferably a nut. The second washer should be rotatably attached to the nut by a clip.</p><p> The first washer and the second washer may include an oblique contact surface. The contact surface should have notches. One of the head and the first washer should have a convex surface. The head and the other of the first washers should have cooperating concave surfaces. The convex surface contacts the concave surface and results in a multiaxial rotation of the first washer with respect to the head. The first washer may include a structure for engagement with the bone fixation device. The structure should consist of a circumferential groove that now accepts the flange of the bone fixation device. The first washer may include a rotating engagement structure. The rotary engagement structure may include a recess that is designed to accept the protrusions of the bone fixation device.</p><p> The locking member may include a structure for engaging with the bone fixation device. The structure should include a recess that is designed to accept the protrusion at the lower end of the bone fixation device.</p><p> The bone fixation device according to the invention preferably has an elongated cannula with a collet for detachably engaging the first washer and for advancing the first washer. The bone fixation device may further include a structure for detachably engaging with the fastener and for advancing the fastener in the collet and in the first washer. The lower end extends from the cannula. The lower end portion preferably has a structure for detachably engaging with the locking member. Fasteners, first washers, and locking members are aligned so that the advancing fasteners advance in the first washer, in the bone, and in the second washer into the locking member. Will be done.</p><p> The system for performing bone fixation includes an implant for bone fixation and a bone fixation device. The implant includes an elongated shaft with 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 rotate multiaxially with respect to the head. The locking member has a structure for engaging with the shaft. The locking member preferably has a second washer that is rotatably engaged with the locking member. The bone fixation device may include an elongated cannula with collets for detachably engaging the first washer and for advancing the first washer. A structure is provided for detachably engaging with 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 are such that the advancing fastener advances in the first washer, in the bone, and in the second washer into the locking member. Is consistent with.</p><p> The method for bone fixation is a fastener with an elongated shaft with a head at one end and a bone piercing tip at the other end, and a shaft that can rotate multiaxially with respect to the head. It comprises providing an implant for bone fixation, including a first sac with a structure for engaging the head and a locking member with a structure for engaging the shaft. The locking member may have a second washer that is rotatably engaged with the locking member.</p><p> The method further comprises providing a bone fixation device, which engages with an elongated cannula having a collet for detachably engaging with a first washer and for advancing the washer, and a fastener. It has a structure for fitting and for advancing the fastener in the collet and in the first washer, and a structure extending from the cannula and detachably engaging the locking member. Including the lower end part. In the fastener, the first washer, and the locking member, the advancing fastener advances in the first washer, in the bone, in the second washer, and into the locking member.</p><p> The method further comprises positioning the bone fixation device so that the bone is located between the cannula and the lower end. Activate the bone fixation device to advance the first washer to the bone. The bone fixation device is then activated to advance the fastener into the first washer, through the bone, and into the locking member.</p>

The bone fixation device 10 according to the present invention is shown in FIG. The bone fixation device 10 has a main body 12 and an elongated housing 14 ending at a lower end portion 16. The bone fixation device 10 has a structure for holding the first washer 20 at the distal end of the elongated housing 14 and the second washer 24 and the locking member 28 at the lower end portion 16. The handle 30 may be provided to grip the bone fixation device 10 and triggers 34 and 38 to operate the bone fixation device 10 during the implant procedure. The guide knob 35 is actuated to rotate the housing 14 and the attached lower end portion 16 for proper placement of the second washer 24. The locking lever 32 may be provided to lock the bone fixation device 10 to the bone after the first washer 20 and the second washer 24 have been properly placed. The locking lever 32 may be unlocked to allow the rearrangement of the first washer 20 and the second washer 24. Knobs 37 may be provided to manually advance the fasteners and apply the appropriate torque.

A slidable protective cannula or sheath 39 may be used to facilitate insertion into the body and to cover the lower end portion 16. FIG. 1a shows a bone fixation device 10 having a protective cannula or sleeve 39 to shield the housing 14 and the lower end portion 16 during the insertion process. 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 should be removable from the main body 12. Another housing 14, lower end portion 16 and guide knob 35 may be attached with another implant for reuse of the main body portion 12.

Implant 40 is shown in Figure 2. The implant 40 consists of a fastener having an elongated shaft 44 and a head 48. The fastener engages the first washer 20, the second washer 24, and the locking member 28. As shown in FIG. 3, the head 48 preferably has a convex surface 54 for use when engaging the first washer 20, as described below. A thread 58 is provided on the shaft 44 to engage the locking member 28. Other engagement structures are possible. A tip 62 is provided to penetrate the bone during the implant procedure. The groove or flute 66 provides space for the bone tip to disperse during insertion into the locking member 28 and carry bone debris away from the tip 62 as the tip advances through the bone. A suitable structure, such as the hexagonal opening 70, is provided for engagement of the fastener 44, which applies 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. 5 to 7. The second washer 24 may have a suitable structure, such as serrations 80, for engaging with the surface of the bone. A modified structure is 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 engaging structure such as a clip 88 for penetrating the opening 89 of the second washer 24 and engaging the opening 84 is provided such that the second washer 24 engages the locking member 28. Be done. The convex surface 92 of the locking member 28 should cooperate with a similar concave surface 96 of the second washer 24. The clip 88 is preferably located in a suitable holding groove 90 of the second washer 24. An opening 104 and a slotted L-shaped groove 108 are provided to engage the corresponding protrusions of the lower end portion 16 to secure the locking member 28 to the lower end portion 16 of the bone fixation device 10.

The first washer 20 is shown in FIGS. 8 to 11. The first washer 20 preferably has a concave surface 114 for cooperating with the convex surface 54 of the head 48 of the fastener 44. The elongated opening 118 is often in the form of a tapered slot and allows the first washer 20 to rotate with respect to the fastener 44. The first washer 20 preferably has a structure for engaging the washer by the bone fixing 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 fixation device 10. This causes the first washer 20 to move forward toward the surface of the bone. An additional structure, such as the recess 130, may be provided for engagement by the bone fixation device 10 to allow rotation of the first washer 20. This helps to position the first washer 20 correctly. The first washer 20 preferably has an inclined contact surface 136 that causes the first washer 20 to cooperate with a bone surface such as a small articular surface at a considerable angle. Additional structures may be provided to facilitate engagement. The structure should include serrations 140 on the contact surface 136. The opening 118 may be further widened like a flute towards the contact surface 136 to allow greater rotation.

The method of engagement between the fastener 44, the first washer 20, the second washer 24, and the locking member 28 is shown in FIGS. 12a to 12c. The rotational movement of the first washer 20 is shown. The first washer 20 should be tilted about 30 ° from the cross section passing through the screw shaft. It is possible to some extent depending on the bone tissue to be fused. The second washer 24 can be tilted by + 45 ° to -20 ° from the cross section with the screw shaft. It is possible to varying degrees.

A suitable structure for engaging the first washer 20 may be provided in the bone fixation device 10. Collet 140 is shown in Figure 13, but other retaining structures are possible. The collet has a distal annular flange 144 that engages the groove 124 of the first washer. A protrusion 148 that engages the recess 130 is provided to allow rotation of the first washer 20. An elongated slot 152 springs into the lower lip 144 so that the collet 140 can engage and disengage from the first washer with moderate manual force. Make spring 153.

14 to 15 show a method for engaging the first washer 20 and the second washer 24 with the bone. The locking member 28 is engaged with the lower end portion 16 in an appropriate slot. The protrusion of the lower end portion 16 can engage the opening 104 of the locking member 28. Bone is schematically shown as the upper articular surface 160 and the lower articular 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 articular 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 aligned with the inclined portion 168 of the lower articular surface 164. Then, when the collet 140 is lowered, the first washer 20 engages with 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 to correctly position the first washer 20 with respect to the inclined portion 172 of the upper small joint surface 160.

The mounting of the fastener 44 is shown in the sequence of FIGS. 16-18. The fastener 44 is held by a suitable engaging portion (not shown) of the bone fixation device 10 and driven towards the upper articular surface 160. The head 48 can be rotated to engage the fastener 44 so that the tip 62 is driven into the upper small joint surface 160. The tip 62 should be provided with a flute that removes bone debris when the fastener 44 is rotated and pushed into the bone. In this way, the fastener 44 drills holes in the upper articular surface 160 and the lower articular surface 164. As the fastener 44 advances through the bone, the fastener 44 engages the locking member 28. The thread 58 is screwed into the female thread of the locking member 28. As a result, as shown in FIG. 19, the fastener 44 is engaged with the locking member 28. The collet 140 can then be removed, as shown in FIGS. 20 and 21. As shown in FIG. 22, when the bone fixing device 10 is removed, the lower end portion 16 is removed. This results in a complete implant across the upper articular surface 160 and the lower articular surface 164, as shown in FIG.

The bone fixation device 10 used during the implant procedure is shown in FIGS. 24 to 26. The bone fixation device 10 has an elongated housing 14 in the general shape of the cannula. A collet 140 is provided in the housing 14. The collet 140 has a structure for engaging with the first washer 20. Any structure is possible, but the collet 140 of FIG. 24 has an inwardly oriented circumferential holding flange 144. The circumferential holding flange 144 engages 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 in the collet 140 is such that a manual force can be used to remove the collet 140 from the first washer 20 after the first washer 20 has been anchored to the bone. Is.

The collet 140 is attached to the housing 14 so that it can move in the housing 14 in the axial direction. The collet 140 may have a structure for slidably engaging with 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 from the position shown in FIG. 24 to the position shown in FIG. 25 in the housing 14. When the gear 230 is rotated, the shaft 210 is pulled out by the threaded end 246 of the shaft. The first washer 20 is seated on the upper articular surface 160 and the second washer 24 is seated on the lower articular surface 164. If the orientation is incorrect, the guide knob 35 can be rotated to properly position the second washer 24. The locking lever 32 can be activated to fix the bone fixation device 10 to the small joint surface.

The action of the trigger 38 then rotates the spiral gear 230, which causes the normally slidable hexagonal or flat chamfer shaft 210 to rotate. This rotates the extension threaded end 246 of the shaft to screw it into 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, for example, a hexagonal tip. Thereby, the rotation of the threaded end 246 rotates and advances the fastener 44. The fastener 44 advances in the first washer 20 and advances in the upper small joint surface 160 and the lower small joint surface 164 by the drilling action caused by the forward movement and rotational movement of the fastener 44. The fastener 44 then proceeds through the second washer 24 and into the locking member 28. The threads 58 of the fastener 44 screw the corresponding threads 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 offers many advantages over the prior art pedicle screw fixation system. Female threads that increase the stress in the bone when the osteosynthesis is squeezed between the first washer 20 and the second washer 24, such as the upper articular surface 160 and the lower articular surface 164. Not present in bones. The threads 58 are located only at the lower end of the shaft 44 so that these threads engage only with the locking member 28 and do not apply thread stress to the inside 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 may be provided with various inclined contact surfaces, each adapted to a different bone shape for joining bone portions other than the small articular surface. Also, the amount of tilt of the first washer 20 and the second washer 24 with respect to the fastener 44 can be adjusted according to the particular bone shape to be joined by the permissible rotation and multiaxial movement. The attachment of 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. Accordingly, the present invention provides great variability and adaptability, in addition to ease of installation, control and one penetration.

The various components of the invention are composed of surgical plastics or metal structures such as titanium. The different dimensions and shapes of the various components of the invention are within the scope of the invention.

The present invention can be practiced in other forms without departing from its spirit or essential qualities and therefore refers to the claims rather than the specification described above to indicate the scope of the invention. Should be.

<figref num="1">It is a perspective view of the bone fixation device by this invention.</figref><figref num="1a">FIG. 3 is a perspective view of a bone fixation device having a protective cannula.</figref><figref num="2">It is a side view of the bone joint fixation implant by this invention.</figref><figref num="3">It is a side view of a fastener.</figref><figref num="4">It is a perspective view.</figref><figref num="5">It is a side view of a tightening member and a washer assembly.</figref><figref num="6">It is a perspective view.</figref><figref num="7">It is a perspective view partially seen through.</figref><figref num="8">It is a perspective view of the first outer surface washer.</figref><figref num="9">It is a bottom perspective view.</figref><figref num="10">It is a bottom perspective view of the modified embodiment.</figref><figref num="11">It is a bottom perspective view partially excised.</figref><figref num="12a">FIG. 5 is a partially excised cross-sectional view showing another orientation.</figref><figref num="12b">It is sectional drawing which showed the deformation orientation and was partially excised.</figref><figref num="12c">FIG. 5 is a partially excised cross-sectional view showing another orientation.</figref><figref num="13">It is a perspective view of a collet.</figref><figref num="14">It is a schematic side view which shows the 1st operation mode.</figref><figref num="15">It is a schematic side view which shows the 2nd operation mode.</figref><figref num="16">It is a schematic side view of a partial excision and a partial cross section.</figref><figref num="17">It is a schematic perspective view which was partially excised.</figref><figref num="18">It is the schematic perspective view of the 2nd operation mode.</figref><figref num="19">It is a partially virtual schematic perspective view of the subsequent operation mode.</figref><figref num="20">It is a schematic perspective view of the other operation mode.</figref><figref num="21">It is a schematic sectional view.</figref><figref num="22">It is the schematic sectional drawing which shows the final mounting.</figref><figref num="23">It is a schematic perspective view which shows the bone fixation using the implant by this invention.</figref><figref num="24">It is schematic cross-sectional view which shows the bone fixation system and method of the 1st operation mode.</figref><figref num="25">It is the schematic sectional drawing which shows the 2nd operation mode.</figref><figref num="26">It is the schematic sectional drawing which shows the 3rd operation mode.</figref>

Code description

10 Bone fixation device 12 Main body 14 housing 16 Bottom part 20 1st washer 24 Second washer 28 Locking member 30 handle 32 Locking lever 34 trigger 35 Guide knob 37 knob 38 trigger