The use of spinal rods is conventional for correction of spinal trauma or conditions, such as curvature of the spine. Generally, an orthopedic stabilization system may include a pair of elongate members, such as spinal rods or plates, that are coupled to a bone or bones. For the sake of simplicity, the term “rod” is used throughout to refer to any elongate member. The rods are generally contoured and longitudinally disposed adjacent to vertebral bodies of a spine.
The strength and stability of the rod assembly can be increased by coupling the two rods with a cross-connector that extends substantially horizontal to the longitudinal axes of the rods across the spine. In some situations, the two rods are geometrically aligned such that the two rods are parallel to each other. However, the two rods are often not three dimensionally geometrically aligned in actual situations. There are several ways to address the variations of geometrical alignment. First, one or both of the rods can be bent to accommodate the transconnector. However, any bending in either of the rods can adversely affect the fixation to the spine and comprise clinical outcome. Furthermore, the bending can also adversely affect the mechanical properties of the rods. The transconnector can also be bent so that the disturbance to the rod positioning is minimized. As is the case with bending of the rods, the mechanical properties of the transconnector could be compromised.
Because of the forces acting along the transverse connector and the movement of the spinal rods, the connection between the transverse connector and the rod must be secure to avoid movement of the transverse connector along the spinal rod. Some rod fastening systems of transverse connectors use threaded fasteners to attach the transverse connector to adjacent rods. The threaded fastener can be a set screw or a nut. Not tightening a threaded fastener enough may allow movement of the transverse connector. Overtightening a threaded fastener could result in damage to the system and failure of the transverse connector.
In view of the foregoing, there exists a need for an improved transconnector for coupling spinal rods. Disclosed is a transconnector for connecting first and second spinal rods that are positioned longitudinally along a spine. The transconnector comprises a first member having a first clamp member adapted to clamp onto a first spinal rod, the first member having a first connecting region extending away from the clamp member; a second member having a second clamp member adapted to clamp onto a second spinal rod, the second member having a second connecting region extending away from the second clamp member toward the first member, wherein the second member and first member are slidably interconnected along the first and second connecting regions; a first interference pin coupled to the first clamp member and adapted to provide an interfering engagement with the first spinal rod to lock the first spinal rod in the first clamp member; a second interference pin coupled to the second clamp member and adapted to provide an interfering engagement with the second spinal rod to lock the second spinal rod in the second clamp member; and a third interference pin coupled to the first and second connecting regions and adapted to provide an interfering engagement between the first and second connecting regions to lock the first and second members in a fixed position relative to one another.
Other features and advantages will be apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the disclosed devices and methods.
Disclosed herein are methods and devices for interconnecting first and second longitudinal members extending along a spinal column of a patient.
A person skilled in the art will appreciate that while each transverse connector 100, 200, 300, 400 is described herein as being adapted to engage a spinal fixation element, and in particular a spinal fixation rod, that a transverse connector disclosed herein can be configured to engage a variety of spinal fixation devices, such as anchors, cables, fixation plates, etc. Moreover, the transverse connectors can include only one connector member for engaging a spinal fixation device, and the opposed terminal end of the transverse connectors can be adapted for other uses. For example, the opposed terminal end of the transverse connectors can be configured to be fixedly attached to a vertebra. The transverse connectors disclosed herein can also include any combination of features described and/or illustrated herein, and the transverse connectors are not limited to the illustrated embodiments.
As indicated above, the transverse connector in certain exemplary embodiments includes a first connecting member and a second connecting member that extend toward each other between each longitudinal member or spinal rod. The first and second connecting members can connect by a variety of mechanisms or configurations. The first and second connecting members can be generally elongate and positioned a distance apart from one another and adjusted transversely. The first and second connecting members can also be rotationally adjustable to allow the connecting members to be positioned as desired. The transverse and rotational adjustability of the transverse connectors allows them to mate to parallel, non-parallel, diverging, and converging spinal rods that are implanted within a patient's spinal system.
Each of the rods 120 (
At least one transverse connector 100 (
The second connecting member 110 is removably connectable with clamp member 115 in contrast to the first connecting member 105, which has an integrated clamp portion 125. Clamp member 115 is independent of the second connecting member 110. The second connecting member 110 is connectable with clamp member 115 by way of a threadable clamp screw 112. Threaded bore 132 of the second connecting member 110 can align with a threaded bore 152 of the clamp member 115. Clamp screw 112 threads through aligned bores 132 and 152 thereby fixing the clamp member 115 to the second connecting member 110. Prior to fixing, the clamp 115 can rotate about the axis of the clamp screw 112 relative to the connecting member 110.
Clamp portion 125 and clamp member 115 each has a recess 107 and 109 (shown in
As mentioned above, the first connecting member 105 has an elongate arm 150 that extends toward the second connecting member 110 and away from the region of bore 146. The second connecting member 110 similarly has an elongate arm 160 that extends toward the first connecting member 105 and away from the region of bore 132. The elongate opening 144 of arm 150 and elongate opening 134 of arm 160 extend generally transverse to the rods 120a, 120b when the rods 120a, 120b are fixed within the recesses 109, 107 by the clamp screws 116, 112, as described above.
The first connecting member 105 and the second connecting member 110 interconnect, as follows. An upper surface of arm 150 contacts a lower surface of arm 160 such that the second connecting member 110 rests atop the first connecting member 105 along transverse axis, shown in
Connecting members 105, 110 are slideably adjustable along transverse axis λ with respect to one another such as in a telescoping manner. The telescoping connecting members 105, 110 can be fixed at a plurality of lengths and into a plurality of positions by set screws 114, 118 as described above. As described above, clamp portion 125 is integral with the first connecting member 105. Second connecting member 110 does not have an integrated clamp mechanism. Instead, clamp member 115 is independent of the second connecting member 110. As best shown in
The connecting members 205, 210 are removably connectable with clamp members 225, 215. The first connecting member 205 is connectable with clamp member 225 by way of a threadable clamp screw 216. Threaded bore 246 of the first connecting member 205 can be aligned with a threaded bore 248 of the clamp member 225. Clamp screw 216 threads through the aligned bores 246, 248 thereby fixing the clamp member 225 to the first connecting member 205. The second connecting member 210 is connectable with clamp member 215 by way of a threadable clamp screw 212. Threaded bore 232 of the second connecting member 210 can be aligned with a threaded bore 252 of the clamp member 215. Clamp screw 212 threads through the aligned bores 232, 252 thereby fixing the clamp member 215 to the second connecting member 210.
Clamp members 215, 225 each has a recess 209 and 207 (shown in
As mentioned above, the first connecting member 205 includes an elongate arm 250. Arm 250 extends toward the second connecting member 210 and away from the region of bore 246. The second connecting member 210 similarly includes an elongate arm 260 that extends toward the first connecting member 205 and away from the region of bore 232. Arm 260 has a groove 234 running through it. The arms 250 and 260 extend toward each other in a generally transverse direction to the rods 120a, 120b when the rods 120a, 120b are fixed within the recesses 207, 209 by the clamp screws 216, 212, as described above.
The first connecting member 205 and the second connecting member 210 interconnect by slideably inserting elongate arm 250 inside of elongate arm 260 and engagement by a set screw 214, described as follows. The elongate groove 234 of the second connecting member 210 has openings at the upper and lower surface of the arm 260 as well as a receiving window 236 at the end nearest the vertebral midline. The receiving window 236 is configured to receive arm 250. In this regard, the receiving window 236 can optionally have a shape that corresponds to the shape of the arm 250. For example, if the cross-sectional shape of the arm 250 is rectangular, the shape of the receiving window 236 is likewise rectangular. In an embodiment, the shape of the elongate groove 234 generally mirrors the cross-sectional shape of the arm 250 such that the arm 250 can be inserted through the elongate groove 234 with little resistance. A mirrored or complimentary shape between the groove 234 and the arm 250 provides a smooth interfit that promotes a clean sliding movement between the groove 234 and the arm 250. However, it is not necessary that the shapes be mirrored or complimentary.
The connection between the arm 250 of the first connecting member 205 inside the arm 260 of the second connecting member 210 is fixed by way of a set screw 214. Upon insertion of the arm 250 into the receiving window 236, threaded bore 242 is aligned with at least a portion of the elongate groove 234. The set screw 214 can be threaded from above through an upper opening of the elongate groove 234 into the threaded bore 242. This fixates the first connecting member 205 inside the second connecting member 210 such that the first and second connecting members interlock transversely along the same horizontal plane.
The arm 250 includes a step 253 that abuts a shoulder 255 on the arm 260 as the arm 250 is inserted into the arm 260. The interface between the step 253 and the shoulder 255 provides a stop that limits movement of the arm 250 into the arm 260. The relative positions of the step 253 and shoulder 255 can be selected to provide a predetermined amount of relative sliding movement between the arms 250 and 260. The interface between the screw 214 and an inner wall 257 of the slot 234 can also limit movement between the arms 250 and 260.
Thus, connecting members 205, 210 are slideably adjustable along transverse axis λ with respect to one another such as in a telescoping manner as shown in
The connecting members 305, 310 are removably connectable with clamp members 325, 315. The first connecting member 305 is connectable with clamp member 325 by way of a threadable clamp screw 316. Threaded bore 346 of the first connecting member 305 can be aligned with a threaded bore 348 of the clamp member 325. Clamp screw 316 threads through the aligned bores 346, 348 thereby fixing the clamp member 325 to the first connecting member 305. The second connecting member 310 is connectable with clamp member 315 by way of a threadable clamp screw 312. Threaded bore 332 of the second connecting member 310 can be aligned with a threaded bore 352 of the clamp member 315. Clamp screw 312 threads through the aligned bores 332, 352 thereby fixing the clamp member 315 to the second connecting member 310.
Clamp members 315, 325 each has a recess 309 and 307 (shown in
As mentioned above, the first connecting member 305 includes a forked region 350 that has parallel arms 356a, 356b extending away from the region of bore 346 toward the second connecting member 310. The second connecting member 310 includes an elongate arm 360 that extends away from the region of bore 332 toward the first connecting member 305. The arms 356a, 356b and arm 360 extend toward each other in a generally transverse direction to the rods 120a, 120b when the rods 120a, 120b are fixed within the recesses 307, 309 by the clamp screws 316, 312, as described above.
The first connecting member 305 and the second connecting member 310 interconnect by positioning elongate arm 360 between parallel arms 356a, 356b of the forked region 350. Arm 360 is positioned between the parallel arms 356a, 356b such that the holes 358a, 358b align with the elongated slot 334. In an embodiment, the shape of arm 360 generally mirrors or complements the shape of the recess of the forked region 350 formed by arms 356a, 356b.
The connection between the first and second connecting members 305, 310 is fixed by way of a set screw 314 and a cross pin 354. Threaded bore 336 extends through the region of the arm 360 located opposite of bore 332. Upon positioning of arm 360 between arms 356a, 356b, holes 358a, 358b are aligned with at least a portion of the elongated slot 334. The cross pin 354 can be inserted through holes 358a, 358b thereby preventing the first connecting member 305 from sliding out of the second connecting member 310. In this manner, the cross pin 354 acts as a detent that limits the amount of telescoping movement (represented by λ in
The connecting member 405, 410 are connectable with clamp members 325, 315. The first connecting member 405 is connectable with clamp member 425 by way of a threadable clamp screw 416. Threaded bore 446 of the first connecting member 405 can be aligned with a threaded bore 448 of the clamp member 425. Clamp screw 416 threads through the aligned bores 446, 448 thereby fixing the clamp member 425 to the first connecting member 405. The second connecting member 410 is connectable with clamp member 415 by way of a threadable clamp screw 412. Threaded bore 432 of the second connecting member 410 can be aligned with a threaded bore 452 of the clamp member 415. Clamp screw 412 threads through the aligned bore 432, 452 thereby fixing the clamp member 415 to the second connecting member 410.
Clamp members 415, 425 each has a recess 409 and 407 (shown in
As mentioned above, the first connecting member 405 includes an elongate arm 450 that extends away from the region of bore 446 toward the second connecting member 410. The second connecting member includes an elongate slot 434 extending through its middle region and a receiving window 436 located below the horizontal plane of the arm 460. Arms 450 and 460 extend toward each other in a generally transverse direction to the rods 120a, 120b when the rods 120a, 120b are fixed within the recesses 407, 409 by the clamp screws 416, 412, as described above.
The first connecting member 405 and the second connecting member 410 interconnect by slidably inserting elongate arm 450 through the receiving window 436 of arm 460 and engagement by a set screw 414, described as follows. The receiving window 436 is configured to receive arm 450 of the first connecting member 405. In this regard, the window 436 has a size that is larger than the cross-sectional size of the arm 450 such that the arm 450 is insertable into the window 436. The window 436 can optionally have a shape that complements or mirrors the cross-sectional shape of the arm 450. For example, if the cross-sectional shape of the arm 450 is rectangular, the shape of the window 436 is likewise rectangular. The shape of the window 436 can generally mirror the cross-sectional shape of arm 450 such that the arm 450 can be inserted through the window 436 with little resistance.
The connection between the arm 450 of the first connecting member 405 inside the arm 460 of the second connecting member 410 is fixed by way of a set screw 414. Upon insertion of the arm 450 through the receiving window 436 of arm 460, threaded bore 442 is aligned with at least a portion of the elongate slot 434. Because the window 436 is positioned below the horizontal plane of arm 460, the upper surface of the arm 450 contacts the bottom surface of arm 460. The set screw 414 can be threaded from above through an upper opening of the elongate slot 434 into the threaded bore 442. This fixates the first connecting member 405 through the receiving window 436 and under the second connecting member 410 such that the first and second connecting members interlock transversely.
When connected, the first and second members 410 and 405 can move relative to one another in a telescoping manner as limited by the set screw 414 abutting the edges of the slot 434. In addition, the clamp portions 415 and 425 can be rotationally adjusted relative to the axes of the screws 412 and 416 as shown by arrow α in
An end of the connecting member 510 also has a clamp member 525, which is removably attached to the connecting member 510. The clamp member 525 has a recess that is sized and shaped to receive an elongate rod therein. A clamp screw 512 couples to a bore in the connecting member 510 such as in a threaded relationship. The clamp screw 512 can be threaded downward toward a rod positioned within the cavity to tighten against the rod and lock it in the cavity. The clamp screw 512 is also used to removably secure the clamp member 525 to the connecting member 510.
With reference to
As shown in
Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, embodiments, methods of use, and combinations thereof are also possible. Therefore the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
This application claims priority of co-pending U.S. Provisional Patent Application Ser. No. 60/898,010 filed Mar. 9, 2007. Priority of the aforementioned filing date is hereby claimed and the disclosures of the Provisional patent application is hereby incorporated by reference in its entirety.