BONE FIXATION TENSIONING TOOL AND METHOD
A tensioning tool and method for tensioning a conformable ligature of a bone fixing system are disclosed. The ends of a conformable ligature can be passed around bones, bone grafts, tendons, plates, rods, fasteners, or other anatomical or implanted structures, and the like to form a loop. Another portion of the conformable ligature can be coupled to a tensioning tool. The tensioning tool can include a first portion and a second portion in threaded engagement with each other. Rotation of one portion relative to the other can cause tensioning of the conformable ligature through translation of a tensioning member.
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This application is a continuation of U.S. patent application Ser. No. 11/877,160, filed on Oct. 23, 2007, the entire disclosure of which is incorporated herein by reference.
TECHNICAL FIELD OF THE DISCLOSUREThis disclosure relates generally to systems and method for fixing bone. In particular, embodiments of the disclosure may be helpful for holding bones, rods, or other structures in a desired configuration or in particular relative position. Even more particularly, the disclosure relates to instruments and methods for installing bone fixing systems.
BACKGROUND OF THE DISCLOSUREThe spine is formed of superposed vertebrae, normally aligned along a vertebral axis, from the lumbar vertebrae to the cervical vertebrae, each having a posterior wall from which projects a spinous process and two lateral edges from the walls of which there project ribs and/or transverse processes. If the spine of a person has abnormal curvature, the vertebrae are typically inclined relative to one another and relative to said vertebral axis. The lateral edges of the vertebrae on one side are therefore closer together and form a concave shape while the lateral edges on the other side are farther apart and form a convex shape.
In order to straighten the vertebral column as a remedy for this situation, the lateral edges of the vertebrae on the concave side can be moved away from one another and supported at distances from one another substantially equivalent to the distances between the lateral edges on the other side. Devices known in the art to hold the vertebrae relative to one another include screws that are inserted into the vertebrae or hooks that are inserted along the internal wall of the spinal canal and rods adapted to connect the screws or hooks.
When using a hook and rod system, pairs of hooks are generally inserted into each vertebra, one on each side, near the pedicle. The hooks typically have heads that project from the posterior wall of the vertebra, one on each side of the spinous process. The heads can be tulip-shaped and adapted to receive a rod that is immobilized by a nut screwed onto the head and contacting the rod. The heads of the hooks situated on either side of the spinous process can then be connected together and fixed in position by two rods approximately parallel to one another and to the axis of the spine.
However, using such hooks can be difficult because their use increases the risk that the physician (or other operative) might contact and potentially damage the spinal cord that extends along the center of the spinal canal (which can result in paralysis of the patient).
Using a screw and rod system reduces this risk, but has other drawbacks. The screws typically have tulip-shaped heads and are inserted in pairs into the pedicles on each side of the spinous process on the posterior wall of the vertebrae. The screws therefore constitute fixing points on the vertebrae for holding the vertebrae in a fixed position relative to one another. However, the screws are inserted into the pedicles of the vertebrae, which in some cases are small or have deteriorated and can be damaged or do not provide sufficient purchase to permanently hold the screw.
SUMMARY OF THE DISCLOSUREAccording to various embodiments described herein, a surgical procedure can be performed using a tensioning tool that provides continuous control over tensioning the ligature. A user can form a loop about one or more structures in a patient's body with a conformable ligature and a ligature capturing implant. The ligature capturing implant can be a ligature capturing implant that include rods, compression members or can be another type of ligature capturing implant. The structures can include, for example, a bone, a bone fastener, a tendon, a bone graft, a plate, a rod or other structure in the body. The user can attach a portion of the conformable ligature to a tensioning member of a tensioning tool that provides a continuous range of control. The tensioning tool can comprise a first portion in threaded engagement with a second portion. For example, the tensioning tool can comprise a drive shaft that engages with a carriage, a column that engages with a threaded shaft, a threaded shaft that engages with another shaft or other threaded portions that engage with each other to translate rotational motion of the portions relative to each other into linear motion of the tensioning member. The user can rotate the first portion relative to the second portion to move the tensioning member to tension the loop. For example, a user can rotate a drive shaft to move a carriage carrying the tensioning member. In some embodiments, the user can disengage the carriage from the drive shaft and slide the carriage along the drive shaft to a selected position. As another example, the user can rotate one portion of the tool to move a shaft that is coupled to the tensioning member. The first portion can also be rotated relative to the second portion in an opposite direction to release tension from the loop.
According to one embodiment, a spinal reduction can be performed using tensioning tools. A method of progressive spinal reduction can comprise forming multiple loops about structures in a patient's body with multiple conformable ligatures and ligature capturing implants and partially tensioning each conformable ligature in turn with a corresponding tensioning tool until each conformable ligature is at a desired tension to perform spinal reduction procedure. Tensioning each conformable ligature may comprise attaching a portion of that conformable ligature to a tensioning member of the corresponding tensioning tool, the corresponding tensioning tool comprising a first portion in threaded engagement with a second portion and rotating the first portion relative to the second portion to move the tensioning member away from a corresponding ligature capturing implant to tension that conformable ligature about at least a portion of a vertebra. The first portion is rotated relative to the second portion about an axis that is substantially parallel to a primary direction of movement of the tensioning member.
Another embodiment of a method comprises providing a tensioning tool comprising, a tool body defining a slot, a threaded drive shaft running through at least a portion of the tool body, a tensioning member and a carriage coupled to the tensioning member. The carriage defines a drive shaft passage having at least one thread engaging portion to engage threads on the drive shaft. The drive shaft passes through the drive shaft passage. The method further comprises forming a loop about one or more structures in a patient's body with a conformable ligature and a ligature capturing implant and coupling a portion of the conformable ligature to the tensioning member. The method can further include rotating the drive shaft to move the carriage away from the ligature capturing implant to tension the conformable ligature. Embodiments can also include rotating the drive shaft the opposite direction to release tension from the loop. The structures about which the loop is formed can include, for example, a bone, a bone fastener, a tendon, a bone graft, a plate, a rod or other structure in the body.
According to one embodiment, the drive shaft passage includes one or more additional unthreaded portions. The method can further comprise rotating the carriage to disengage the at least one thread engaging portion from the threaded drive shaft and sliding the carriage along the drive shaft to a desired position.
Another embodiment of a method for holding a bone in a position, the method comprises passing a conformable ligature around one or more structures in a body, passing first and second ends of the conformable ligature through a loop passage in a ligature capturing implant to form a loop, adjusting the ligature capturing implant to increase to resistance on the movement of the conformable ligature to a selected amount that allows the conformable ligature to move through the ligature capturing implant when a force is applied to the conformable ligature, attaching a portion of the conformable ligature to a tensioning member of a tensioning tool, rotating a threaded drive shaft of the tensioning tool to move the tensioning member to apply tension to the conformable ligature and adjusting the ligature tensioning implant to prevent the loop from loosening. According to one embodiment, rotating a threaded drive shaft of the tensioning tool to move the tensioning member comprises rotating the threaded drive shaft to move a carriage coupled to the tensioning member. The carriage can define a drive shaft passage having at least one thread engaging portion to engage threads on the drive shaft and wherein the drive shaft passes through the drive shaft passage. The method can further comprise positioning the tensioning tool so that a connecting portion of the tensioning tool abuts the ligature capturing implant. According to one embodiment the drive shaft can be rotated in an opposite direction to release tension from the conformable ligature.
According to one embodiment a drive shaft passage can include one or more additional unthreaded portions. The method can further include rotating the carriage to disengage the at least one thread engaging portion from the threaded drive shaft and sliding the carriage along the drive shaft to a desired position.
Another embodiment comprises a tensioning tool providing continuous control of conformable ligature tension, the tensioning tool comprising a tool body defining a slot, a connection portion shaped to at least abut a ligature capturing implant, a threaded drive shaft running through at least a portion of the tool body, a tensioning member and a carriage coupled to the tensioning member, the carriage defining a drive shaft passage having at least one thread engaging portion to engage threads on the drive shaft and wherein the drive shaft passes through the drive shaft passage, wherein rotation of the drive shaft causes the carriage to move towards or away from the connection portion. According to one embodiment, the carriage is configured to be rotated from a first position in which the at least one thread engaging portion is engaged with threads on the drive shaft to a second, slidable position, in which the at least one thread engaging portions is not engaged with the threads of the drive shaft.
The tensioning tool can further comprise a drive shaft seat in which a first end of the drive shaft is seated, a spring that compresses between the drive shaft seat of and the tool body, and a removable handle connected to a second end of the drive shaft distal from the first end.
Embodiments of the disclosed systems and methods can provide the advantage of providing progressive and continuous tensioning of a ligature used in bone fixing procedures.
Embodiments of the disclosed systems and methods can provide the advantage of allowing tension of the ligature to be progressively reduced in an easily controlled manner.
Embodiments of the disclosed systems and methods provide another advantage by allowing a tensioning tool used to tension one ligature to be left in place while the other ligatures are tightened.
The disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well known starting materials, processing techniques, components and equipment are omitted so as not to unnecessarily obscure the disclosure in detail. Skilled artisans should understand, however, that the detailed description and the specific examples, while disclosing preferred embodiments of the disclosure, are given by way of illustration only and not by way of limitation. Various substitutions, modifications, additions or rearrangements within the scope of the underlying inventive concept(s) will be apparent to those skilled in the art after reading this disclosure.
A bone fixing system may be installed in a patient to hold or fix one structure in a selected relation with one or more other structures. As used herein, the term structure may refer to bones, portions of bones, or bone implants, as well as rods, elongated members, plates, or other implanted man-made devices. Among other methods, a bone fixing system as described herein may be installed using a minimally invasive surgery (MIS) procedure. In one embodiment, the bone fixing system and method of use may include instruments and bone fixing components for maintaining one or more structures in a selected alignment.
Components of bone fixing systems in accordance with the disclosure may be made of materials including, but not limited to, titanium, titanium alloys, stainless steel, ceramics, and/or polymers. Some components of a bone fixing system may be autoclaved and/or chemically sterilized. Components that may not be autoclaved and/or chemically sterilized may be made of sterile materials. Components made of sterile materials can be used with other sterile components during assembly of a bone fixing system.
Embodiments of bone fixing systems disclosed herein are useful in repairing broken bones, correcting curvatures of the spine and for other surgical procedures that hold structures (e.g., bones) in a fixed relative position. Embodiments of the bone fixing system and method of use disclosed herein can be particularly useful for minimally invasive surgery (MIS) procedures, which can reduce trauma to soft tissue due to the relatively small incision made in a patient. For example, a surgical procedure may be performed through a 2 cm to 4 cm incision formed in the skin of the patient. Dilators, a targeting needle, and/or a tissue wedge may be used to provide access to structures without the need to form a larger incision with a scalpel through muscle and other tissue. A minimally invasive surgery (MIS) procedure may reduce an amount of post-operative pain felt by a patient as compared to invasive procedures. A minimally invasive procedure may also reduce recovery time for the patient as compared to invasive procedures. In some embodiments, the natural flexibility of skin and soft tissue may be used to limit the length and/or depth of an incision or incisions needed during the procedure. Minimally invasive procedures may provide limited direct visibility in vivo.
Bone fixing systems may be used to correct problems due to spinal injury, deformity, or disease. For example, various embodiments of a bone fixing system may be used from the C1 vertebra to the sacrum to correct spinal problems. For example, a bone fixing system may be implanted posterior to the spine to maintain distraction between adjacent vertebral bodies in a lumbar portion of the spine. Various embodiments of a bone fixing system may be used to correct orthopedic deficiencies. Embodiments of the disclosure may be useful for holding tendons, bones, or muscles during the healing process and may be implanted using MIS procedures and thus it is in this context that embodiments of the disclosure may be described. It will be appreciated, however, that embodiments of the systems and methods of the present disclosure may be applicable for stabilizing other areas of the body.
In general, a flexible ligature can be used to secure bones or other structures. The ligature comprises an elongate flexible member capable of conforming to the contour of the parts that it connects. The ligature can be passed through a ligature capturing implant to form a loop that is looped about the structures to fixed relative to each. The ligature capturing implant can be any body through which the ligature passes to form a loop and that allows the loop to be tightened and left in a patient's body in a tightened state. According to one embodiment, force is applied to the ligature to tension the loop. The instrument used to tighten the ligature can include a first shaft, a second shaft drivably engaged with the first shaft and a tensioning member. The tensioning member can be coupled to the first shaft or the second shaft or can be drivably engaged with one or both of the first shaft and the second shaft. A portion of the ligature couples to the tensioning member such that movement of tensioning member can increase the tension in the ligature. For example, a portion of the ligature can be formed into a loop that is looped around the tensioning member. Movement of the tensioning member can be driven by rotational movement of the first shaft relative to the second shaft. Embodiments of an instrument tensioning the ligature are discussed below in conjunction with
By way of context,
The ligature 14 consists of an elongate flexible member capable of conforming to the contour of the parts that it must connect.
The ligature 14 has a first end 44 that is ligated around the pin 24 and a free second end 42 that is inserted into a passage 48 between the rod 18 and the internal walls 50 and 52 of the longitudinal members 22 and 20 and the external wall of the rod 18. As shown in
As shown in
In some embodiments, the first portion of the middle part forms an edge with cylindrical symmetry and that the corresponding second portion of the middle part 58 of the first longitudinal member 22 forms a substantially cylindrical space 60 into which said rod 18 is inserted.
In some embodiments, as shown in
In
The ligature 14 is advantageously made from a flexible material such as polyester that may be lightly crushed locally to immobilize it with a clamping effect.
One aspect of the disclosure relates to a spine straightening assembly comprising a plurality of vertebral fixing systems conforming to the present disclosure and mounted on a plurality of successive vertebrae, on all the transverse processes of one lateral wall thereof, and connected to a single rod that is disposed substantially parallel to said spine. The transverse processes of a portion of the spine can therefore be connected together by a single longitudinal rod, to fix them in position relative to each other, by means of the above vertebral fixing system.
In some embodiments, flexible ligature 14 may not be ligated around pin 24 or otherwise fixed to connecting part 12. As shown in
In
In the embodiment described, the locking means are constituted by a screw 26 having a head 26a that is engaged in a bore 28 formed in the first end 22a of the longitudinal element 22. The first end 20a of the longitudinal element 20 is pierced by a tapped bore 38 for co-operating with the threaded shank 26b of the screw 26. Each longitudinal element 20, 22 has an outside face 20c, 22c and an inside face 20d, 22d. The longitudinal elements 20 and 22 are mounted in such a manner that the inside faces 20d, 22d of the longitudinal elements face each other. The inside faces 20d, 22d of the longitudinal elements 20 and 22 have respective mutually-facing recesses 30 and 32, each of substantially semicylindrical shape. The recesses 30 and 32 define walls 34 and 36 which are ruled surfaces having generator lines parallel to the pivot axis 24. Finally, slots 54 and 40 cause the bottoms of the recesses 30 and 32 to communicate with the outside faces 20c and 22c of the longitudinal elements 20 and 22. As explained below, the recesses 30 and 32 are for receiving the rod 18 together with a strand of the ligature 14, the slots 54 and 40 serving to pass the ligature 14.
With reference to
In
As shown in
In this locking position, the rod 18 is thus secured to the ligature 14 via the connecting part 12.
Advantageously, because the surgeon exerts traction only on the free ends 42 and 44 of the ligature 14, there is no risk of jamming between the ligature 14 and the bottom face of the transverse process or of the rib, thus guaranteeing that effective fastening is provided with the transverse process or the rib or indeed a portion of the posterior arc of a vertebra.
In the above description, both of the portions 42 and 44 of the ligature 14 are disposed in the recesses 30 and 32 on the same side of the rod 18. In some embodiments, the portions 42 and 44 of the ligature 14 may be placed on opposite sides of the rod 18. Under such circumstances, it should be considered that the outside face 18a of the rod 18 and the inside walls of the recesses 30 and 32 define two passageways, respectively for passing each of the portions 42 and 44 of the ligature 14.
In this embodiment, the connecting part 12 is constituted by a part 55 that is generally U-shaped. The inside wall of this part 55 is constituted by a bottom 57 of substantially semicylindrical shape and by two substantially plane portions 53 and 54 that correspond to the two limbs of the part 55. The width of the recess 58 formed in the part 55 is substantially equal to the diameter of the rod 18. On its outside face 59 which is circularly symmetrical about a longitudinal axis of the part 55, there is provided a thread 60 occupying its upper portion. The thread 60 is located entirely above the rod 18 when it is put into place in the recess 58. The thread 60 is designed to co-operate with a clamping ring 62 that constitutes the adjustable locking means. This ring has a slightly frustoconical bore 64 with an inside face 66 that carries tapping 68.
In some embodiments, when the ring 62 is screwed tight on the threaded portion 60 of the part 55, it deforms the limbs of the part 55 elastically, thereby pinching and clamping strands of the ligature 14 between the rod 18 and the inside wall(s) of the recess 58, in a manner explained below.
As shown in
With references to
In the configuration shown in
One advantage to this type of embodiment may be the ability to avoid making two longitudinal parts constituting a kind of clamp hinged on the pin 24. In some embodiments, the locking means are constituted by an element that is distinct from the connecting part and that is removable therefrom. In some embodiments, the locking means co-operate with the connecting part by screw engagement. It is thus possible to adjust accurately the dimensions of the ligature-passing passageway(s) as defined by the connecting part and the rod. In an initial stage, the coefficient of friction between the coefficient of the ligature and secondly the rod and the connecting part can be adjusted. In the final stage, very effective clamping of the ligature is obtained between the rod and the locking part.
In some embodiments, including for example the embodiments shown in
With reference to
In other embodiments that do not require the use of rod 18 to hold a structure in a relative position, bone fixing system 100 may include closure member 130 for engagement with engagement portion 123 of blocking body 120 and for contact with compression member 140 so that advancing closure member 130 into blocking body 120 biases compression member 140 onto conformable ligature 14. Closure member 130 may be advanced into blocking body 120 for biasing compression member 140 against conformable ligature 14 to create a friction force between conformable ligature 14 and blocking body 120. A friction force between conformable ligature 14 and blocking body 120 may hold conformable ligature 14 in place without significant movement relative to blocking body 120. In some embodiments, closure member 130 may be advanced into blocking body 120 for impinging conformable ligature 14 between compression member 140 and blocking body 120 to prevent any relative movement.
Advantageously, the use of compression member 140 in these embodiments enable bone fixing system 100 to be used in circumstances in which rod 18 may be undesirable or unnecessary. Another advantage of the embodiments illustrate in
As shown in
As shown in
As shown in
In some uses, ligature 14 may have one or both ends passed around a structure in the body. Both ends of ligature 14 may be inserted in loop passage 126 to form a loop around the structures. Compression member 140 may be inserted in compression member opening 124. Ligature 14 may be passed through the passageway formed between first surface 146 of compression member 140 and inner surface 125 of blocking body 120. Ends of ligature 14 may be passed out one or more exit passages 128. Closure member 130 may be inserted in engagement portion 123 to engage threads 122. Ends of ligature 14 may be connected to tensioning tool 250, such as tensioning tool 250 shown in
As shown in
Extensions 142 (such as flanges 142) of compression member 140 can operate to prevent compression member 140 from shifting or moving out of position once closure member 130 has engaged engagement portion 123 of blocking body 120. In operation, closure member 130 will contact compression member 140 to hold ligature 14 substantially in place when ligature 14 has been positioned to hold a bone or other structure in a relative position. In some embodiments, extensions 142 may extend around the entire arclength of first surface 146 of compression member 140, such as flanges 142 depicted in
As shown in the embodiment of
Various mechanisms can be used to allow closure member 130 to engage engagement portion 123 of blocking body 120. In some embodiments, closure member 130 has helically wound thread 132 and can be advanced in blocking body 120 through engagement passage 123 by rotating closure member 130 to engage threads of engagement portion 123 of blocking body 120. In some embodiments, tool portion 134 on closure member 130 can be a hex shaped receiving are that would allow a surgeon to use a hex tool to engage and rotate closure member 130 so that threads 132 engage with the threads of engagement portion 123. In some embodiments, closure member 130 may have a sawtooth profile or other profile for ratcheting closure member 130 into blocking body 120. Those of ordinary skill in the art will recognize a variety of other mechanisms (some of which will be described herein) for engaging closure member 130 with engagement portion 123 in order to enable closure member 130 to contact compression member 140 and secure in place ligature 14.
Advantages to embodiments of bone fixing systems 100 such as the one depicted in
Compression member 140 can be placed within channel 127 with surface 146 contacting inner wall 125 at the bottom of channel 127. Closure member 130 may be inserted into channel 127 (e.g., by engaging the exterior threads on the body of closure member 130 with the interior threads of channel 127) for engaging engagement portion 122. Advancing closure member 130 down channel 127 (e.g., rotating closure member 130) can force compression member 140 against ligature 14 to hold ligature 14 in place without significant movement (or with complete impingement) relative to blocking body 120.
Engaging closure member 130 in engagement portion 122 of blocking body 120 prevents all or significant movement of conformable ligature 14 relative to blocking body 120.
As shown in
As described, closure member 130 may be top-loaded into blocking body 120 for the embodiments of
In various embodiments, hinge pin 178 connects first portion 170 to second portion 180 in either a permanent manner or alternatively the hinged connection may be disconnectable. The hinged connection can be formed so as to allow two-way hinged motion for engaging or disengaging first portion 170 from second portion 180. In an alternative embodiment, the hinged connection may allow one-way hinged motion for engaging first portion 170 from second portion 180 but may subsequently prevent first portion 170 from disengaging second portion 180. In various embodiments, first portion 170 and/or second portion 180 may allow hinged motion between a selected arclength, for example, first portion 170 and second portion 180 may move through an arc of approximately 180 degrees.
As further shown in
First surface 146 of compression member 140 and inner surface 125 of blocking body 120 provide a passageway through blocking body 120. In some embodiments, inner surface 125 may be located on first surface 170 and first surface 146 of compression member 140 may be located on second portion 180 as depicted in
Closure member 130 may be offset from compression member 140 such that threaded engagement of threads 132 of closure member 130 with engagement portion 122 of blocking body 120 may indirectly apply compression to compression member 130. In other words, compression member 140 may be positioned some distance L.sub.b from hinge pin 178 and closure member 130 may be positioned some distance L.sub.s from hinge pin 178. Compression of compression member 140 onto conformable ligature 14 may not be accomplished by directly contacting bottom surface 135 of closure member 130, but may instead be accomplished by rotatably engaging threads 132 with threads 122 to advance closure member 130 in blocking body 120 such that second portion 180 may be leveraged around the fulcrum created by hinge pin 178. An advantage to one embodiment uses the mechanical advantage of L.sub.s/L.sub.b to apply compression forces on conformable ligature 14. Another advantage to one embodiment is the ability for the surgeon to apply large compression forces to conformable ligature 14 due to the mechanical advantage based on the position of hinge pin 178, compression member 140, and closure member 130. The compression forces available may also be based on the radius of curvature of compression member 140, the size or pitch of threads 132 and 122, and/or the size of hinge pin 178. Another advantage may be the precision in which a friction coefficient may be selected between conformable ligature 14 and blocking body 120. In some embodiments, the pitch, shank diameter, or other dimensions of closure member 130 may enable control of the application of compression. For example, a large number of threads per inch may allow more compression due to the mechanical advantage of threads 122 engaging with threads 132, and the application may be more controlled due to the greater angular rotation needed to advance closure member 130 the same distance as closure members 130 having lower numbers of threads per inch. Another advantage to this embodiment relates to the outer surface of first portion 170 and/or second portion 180. Because blocking body 120 can achieve a mechanical advantage through the use of hinge pin 178, closure member 130 may be made smaller than prior art approaches, which allows blocking body 120 to have a smaller opening 123. As shown in
It should be understood that the various closure mechanisms, closure members, exit passages, and blocking bodies, and other design features shown in the various embodiments of bone fixing system 100 of
Bone fixing systems 100 may be implanted without affecting plates, rods, or other implanted structures. Bone fixing systems may be implanted without affecting bone screws, hooks, bolts, or other implanted hardware.
Bone fixing system 100 may be advantageous for correcting alignment of one or more bones. Conformable ligatures 14 and blocking bodies 120 may be useful for correcting alignment of a portion of the spine.
In some embodiments, passing may include going into, through, or out of a structure. In some embodiments, passing may include going over, under, or around a structure. In some embodiments, passing may include crossing over other ligatures 14 or portions of ligatures 14. In some embodiments, passing may include multiple passes along the same path
Advantageously, conformable ligature 14 may be selectively passed around structures such as bones and bone grafts. Conformable ligature 14 may be passed around a bone, bone graft, tendon, or other tissue due to disease, injury, tumor, degenerative effects or the like. For example,
In some embodiments, the surgeon may pass conformable ligature 14 alternative ways due to disease, injury, tumor, degenerative effects or the like. For example,
An advantage to bone fixing system 100 is that the position of blocking body 120 may be based on disease, injury, tumor, degenerative effects or the like. For example,
Two or more conformable ligatures 14 and/or two or more blocking bodies 120 may be used to hold a bone, bone graft, tendon, rod, shaft, or other structure in a body.
Attachment point 274 can attach first and second ends of conformable ligature 14 to tensioning tool 250. In some embodiments, attachment point 274 may include flange 258 for preventing first and second ends of conformable ligature 14 from detaching from tensioning tool 250. Distal end 154 (such as the embodiments shown in
In some embodiments, tool body 266 may include return spring 262, catch mechanism 264, and return spring adjustment member 270 for controlling the distance that longitudinal member 260 is allowed to return when movable handle 252 is released. In some embodiments, return spring 262 may bias catch mechanism 264 such that movement is permitted in one direction only. In some embodiments, return spring 262 may bias catch mechanism 264 such that longitudinal member 260 may only move forward through tool body 266. Advantageously, return spring 262 may ensure that a surgeon does not inadvertently relieve tension from conformable ligature 14. In other words, tensioning tool 250 may have a default configuration for tensioning conformable ligature 14. In some embodiments, actuating catch mechanism 264 (such as a surgeon pressing on catch mechanism 264 with a thumb) may change the positioning of catch mechanism 264 such that movement of longitudinal member 260 is permitted in a reverse direction as well. In some embodiments, movement of longitudinal member 260 in a reverse direction may include changing the positioning of catch mechanism 264 in relation to longitudinal member 260 as well as pulling in a reverse direction on grasping member 272.
In some embodiments, tensioning tool 250 may include spring adjustment member 268 for adjusting the compression on a spring (not shown) in body 266. In some embodiments, rotating spring adjustment member 268 one direction, spring adjustment member 268 may be advanced some distance into body 266 such that a spring may be compressed. In some embodiments, rotating spring adjustment member 268 in the other direction, spring adjustment member 268 may be advanced some distance out of body 266 such that compression forces on the spring may be relieved. By changing the compression forces on the spring, the spring may exert more or less force on longitudinal member 260, which may affect how much tension can be applied to the ends of conformable ligature 14.
In some embodiments, ligature 14 may be passed around elongate members 210, bone fastener assemblies 212, vertebrae (such as L5), and other tendons, muscles, plates or other anatomical or implanted structures and the ends of ligature 14 may be passed into a portion of blocking body 120, such that a loop is formed extending from a first portion of blocking body 120. In some embodiments, first and second ends of ligature 14 may be passed through a passage in blocking body 120. In some embodiments, a passage may be formed by inner surface 125 of blocking body 120 and first surface 146 of compression member 140. In some embodiments, first and second ends of ligature 14 may exit by passing out of one or more exit passages 128 in blocking body 120.
Distal end 154 of tensioning tool 250 engages blocking body 120. In some embodiments, distal end 154 of longitudinal member 260 may conform to the shape or profile of blocking body 120. In some embodiments, distal end 154 of longitudinal member 260 may be configured with features for engaging one or more features on blocking body 120. In some embodiments, first and/or second ends of ligature 14 may be attached to tensioning tool 250. In some embodiments, first and/or second ends of ligature 14 may be attached to attachment point 274 located on tool body 266. In some embodiments, movable handle 252 of tensioning tool 250 may be rotated about axis 256 to advance longitudinal member 260 through tool body 266. The advancement of longitudinal member 260 through tensioning tool 250 moves attachment point 274 away from blocking body 120, pulling ends of ligature 14 to decrease the size of the loop, and further advancement tensions ligature 14. In some embodiments, the tension applied to ligature 14 may be sufficient to hold one or more structures in a desired position. In some embodiments, the tension applied to ligature 14 may be sufficient to hold a bone in a position. In some embodiments, the tension applied to ligature 14 may be sufficient to pull one or more bones or structures into alignment. For example, tensioning tool 250 may provide sufficient tension to one or more ends of ligatures 14 (depicted in
In some embodiments, once an appropriate tension has been applied to ligature 14, closure member 130 may be actuated to create a friction force to restrict movement of ligature 14 relative to blocking body 120, or to impinge ligature 14 in blocking body 120. In some embodiments, closure member 130 may be pre-installed in blocking body 120. In some embodiments, closure member 130 may be inserted in blocking body 120 after engagement of blocking body 120 by tensioning tool 250. In some embodiments, closure member 130 may be inserted through distal end 154 of longitudinal member 260 into blocking body 120.
In some embodiments, once closure member 130 has engaged threads 122 in blocking body 120 to provide a desired friction force to impinge ligature 14 in blocking body 120, first and second ends of ligature 14 may be disconnected from tensioning tool 250. Once ligature 14 has been disconnected from tensioning tool 250, tensioning tool 250 may be disengaged from blocking body 120.
The tensioning tool of
Another issue with tensioning tool 250 is that it is difficult for a surgeon to release a selected amount of tension in ligature 14. If a surgeon believes that ligature 14 has been over tensioned, the surgeon must typically release all or a large amount of tension in ligature 14 and begin tensioning ligature 14 again.
Moreover, tensioning tool 250 is relatively bulky. This makes it difficult to have multiple tensioning tools in place at the same time during a procedures. Consequently, tensioning multiple ligatures can be take a significant amount of time as the tensioning tool 250 may have to be removed from a surgical site each time a surgeon wishes to tension a new ligature. This especially inefficient in procedures in which a surgeon may wish to tension each ligature a little at a time rather than tensioning one ligature completely, then moving to the next ligature.
Tensioning tool 300 also includes a connector 335 shaped to interface with a ligature capturing implant (e.g., such as the connection parts shown in
As illustrated in
Tensioning tool 300 further includes a handle that provides an ergonomic user control to rotate drive shaft 310. According to one embodiment, the handle can connect to drive shaft 310 at quick connect 330. At the other end, drive shaft 310 can rest in a drive shaft seat 364 that is movable in tool body 305. A spring 365 between drive shaft seat 364 and tool body 305 allows drive shaft 310 to be pushed towards connector 335. This can dampen forces applied to the drive shaft towards connector 335 (e.g., by the surgeon inadvertently pushing on then handle). Furthermore, since spring 365 will have a known displacement per unit force applied, a measure of displacement of spring 365 indicates how much tension is applied to the ligature (i.e., the force from the tensioned ligature is transferred through carriage 315 to drive shaft 310 to compress spring 365 a known displacement). According to one embodiment, tensioning tool 300 can include features (such as extensions 366) that are coupled to the drive shaft. Extensions 366 move forward as drive shaft 310 moves forward when spring 365 compresses. The position of extensions 366 can be compared to markings on body 305 to determine the force applied to the ligature. Preferably, spring 365 is selected so that spring 365 is fully compressed at between 500 Newtons and 1500 Newtons.
In operation, a surgeon can form a loop about one or more structures with a conformable ligature and a ligature capturing implant Examples of ligature capturing implants are shown in
Before or after attaching the ligature to tensioning member 325, the surgeon can bring connector 335 into contact with the ligature capturing body so that connector 335 pushes against the ligature capturing body as the ligature is tensioned. Rotating drive shaft 310 causes carriage 315 to move along slot 320. As carriage 315 moves, a portion of the conformable ligature is pulled causing the loop about the various structures to tighten. When the surgeon determines that the ligature is sufficiently tightened about the structures to be fixed, the surgeon can tighten the ligature capturing implant so that the ligature does not move within the ligature capturing implant thereby securing the loop about the structures. In other embodiments, the ligature capturing implant may be configured to allow the ligature to be tightened but not loosened. Consequently, once the surgeon is satisfied with the tension in the loop, the surgeon does not have to further adjust the ligature capturing implant to prevent loosening of the loop. Preferably, tensioning tool 300 can apply a tensioning force of at least between 300 and 1500 Newtons to the conformable ligature.
When the loop about the structures is secure, the surgeon can rotate drive shaft 310 in the opposite direction to move carriage 315 towards connector 335. This will release the tension from the portion of the ligature between tensioning member 325 and the ligature capturing implant to allow the surgeon to remove the tensioning tool 300.
The embodiment of
Another advantage is provided in procedures in which multiple ligatures are being installed. In some cases, surgeons find it desirable or necessary to use multiple ligatures. In such procedures, the surgeon will often want to tension each ligature a little at a time. For example, if there are three ligatures, the surgeon will tension the first ligature a small amount, then tension the second ligature a small amount, then tension the third ligature a small amount, then return to the first ligature and tension it some more and so on until all the ligatures are tensioned the appropriate amount. The embodiments of
Tensioning tool 300 also includes a connector 335 shaped to interface with a ligature capturing implant (e.g., such as the connection parts shown in
In the embodiment of
The ability to selectively disengage thread engaging portions 380 so that the user can slide carriage 315 may make the various portions of the tensioning procedure more efficient. Rather than having to rotate drive shaft 310 to move carriage 315 to a position in which the conformable ligature begins to tension, a user can slide carriage 315 to that position (or other desired position) and then rotate drive shaft 310 to further tension the conformable ligature. Additionally, once the tension of the loop about the various structures in the body has been set by fully closing the ligature capturing implant to prevent loosening of the loop, the user can simply slide carriage 315 along drive shaft 310 to remove tension from the portion of the conformable ligature attached to tensioning member 325. Additionally, if for some reason a user determines that tension must be released from the conformable ligature quickly, the user can do so by sliding carriage 315 rather than rotating drive shaft 310.
In the embodiment of
In the previous embodiments, tensioning member 325 is carried by carriage 315 that moves along drive shaft 310 as drive shaft 310 rotates. In other embodiments, the tensioning member is located at the end of a movable shaft.
Tensioning tool 400 can include an end 425 that contacts ligature capturing implant 420. According to one embodiment, the end of tensioning tool 400 can act as a tool portion to tighten a rotatable ring or other portion of ligature capturing implant 420 to capture the conformable ligature in ligature capturing implant 420. As one example, end 425 can be adapted to engage with tool portions 134 of the ligature capturing implant shown in
Thus, like the embodiments of
In the above embodiments, a portion of the tensioning tool is rotated to translate a tensioning member. While specific embodiments are shown, other embodiments of translating a tensioning member can be used. For example, the tensioning member can be coupled to the tool body. As a shaft advances due to rotation either of the shaft or another portion of the tensioning tool in threaded engagement with the shaft, the tool body and consequently, the tensioning member can be pushed away from the ligature capturing implant causing tension in the ligature to increase. The tension can be reduced by rotating the portions of the tensioning tool in threaded engagement in the opposite direction relative to each other.
According to various embodiments, a surgical procedure can be performed using a tensioning tool that provides continuous control over tensioning the ligature. A user can form a loop about one or more structures in a patient's body with a conformable ligature and a ligature capturing implant. The ligature capturing implant can include ligature capturing comprising rods, compression members or other ligature capturing implant. The structures can include, for example, a bone, a bone fastener, a tendon, a bone graft, a plate, a rod or other structure in the body. For example, the loop can be placed about a portion of a vertebra. The user can attach a portion of the conformable ligature to a tensioning member of a tensioning tool that provides a continuous range of control. The tensioning tool can comprise a first portion in threaded engagement with a second portion. The user can rotate the first portion relative to the second portion to move the tensioning member to tension the loop. For example, a user can rotate a drive shaft to move a carriage carrying the tensioning member. In some embodiments, the user can disengage the carriage from the drive shaft and slide the carriage along the drive shaft to a selected position. As another example, the user can rotate a portion of a tool engaged with a threaded shaft to cause the cause the shaft to move. The first portion can also be rotated relative to the second portion in an opposite direction to release tension from the loop. The method can further comprise positioning the tensioning tool so that a connecting portion of the tensioning tool abuts the ligature capturing implant.
According to one embodiment, a spinal reduction can be performed using tensioning tools. A method of progressive spinal reduction can comprise forming multiple loops about structures in a patient's body with multiple conformable ligatures and ligature capturing implants and partially tensioning each conformable ligature in turn with a corresponding tensioning tool until each conformable ligature is at a desired tension to perform spinal reduction procedure. Tensioning each conformable ligature may comprise attaching a portion of that conformable ligature to a tensioning member of the corresponding tensioning tool, the corresponding tensioning tool comprising a first portion in threaded engagement with a second portion and rotating the first portion relative to the second portion to move the tensioning member away from a corresponding ligature capturing implant to tension that conformable ligature about at least a portion of a vertebra. The first portion is rotated relative to the second portion about an axis that is substantially parallel to a primary direction of movement of the tensioning member.
Another embodiment of a method comprises providing a tensioning tool comprising, a tool body defining a slot, a threaded drive shaft running through at least a portion of the tool body, a tensioning member and a carriage coupled to the tensioning member. The carriage defines a drive shaft passage having at least one thread engaging portion to engage threads on the drive shaft. The drive shaft passes through the drive shaft passage. The method further comprises forming a loop about one or more structures in a patient's body with a conformable ligature and a ligature capturing implant, coupling a portion of the conformable ligature to the tensioning member and rotating the drive shaft to move the carriage away from the ligature capturing implant to tension the conformable ligature. Embodiments can also include rotating the drive shaft the opposite direction to release tension from the loop. The structures about which the loop is formed can include, for example, a bone, a bone fastener, a tendon, a bone graft, a plate, a rod or other structure in the body. For example, the loop can be located about at least a portion of a vertebra for a spinal reduction procedure.
According to one embodiment, the drive shaft passage of the carriage includes one or more additional unthreaded portions. The method can further comprise rotating the carriage to disengage the at least one thread engaging portion from the threaded drive shaft and sliding the carriage along the drive shaft to a desired position.
Another embodiment of a method comprises passing a conformable ligature around one or more structures in a body, passing first and second ends of the conformable ligature through a loop passage in a ligature capturing implant to form a loop, adjusting the ligature capturing implant to increase to resistance on the movement of the conformable ligature to a selected amount that allows the conformable ligature to move through the ligature capturing implant when a force is applied to the conformable ligature, attaching a portion of the conformable ligature to a tensioning member of a tensioning tool, rotating a threaded drive shaft of the tensioning tool to move the tensioning member to apply tension to the conformable ligature and adjusting the ligature tensioning implant to prevent the loop from loosening. According to one embodiment, rotating a threaded drive shaft of the tensioning tool to move the tensioning member comprises rotating the threaded drive shaft to move a carriage coupled to the tensioning member. The carriage can define a drive shaft passage having at least one thread engaging portion to engage threads on the drive shaft and wherein the drive shaft passes through the drive shaft passage. The method can further comprise positioning the tensioning tool so that a connecting portion of the tensioning tool abuts the ligature capturing implant. According to one embodiment the drive shaft can be rotated in an opposite direction to release tension from the conformable ligature.
According to one embodiment a drive shaft passage can include one or more additional unthreaded portions. The method can further include rotating the carriage to disengage the at least one thread engaging portion from the threaded drive shaft and sliding the carriage along the drive shaft to a desired position.
Another embodiment comprises a tensioning tool providing continuous control of conformable ligature tension, comprising a tool body defining a slot, a connection portion shaped to at least abut a ligature capturing implant, a threaded drive shaft running through at least a portion of the tool body, a tensioning member and a carriage coupled to the tensioning member, the carriage defining a drive shaft passage having at least one thread engaging portion to engage threads on the drive shaft and wherein the drive shaft passes through the drive shaft passage, wherein rotation of the drive shaft causes the carriage to move towards or away from the connection portion. According to one embodiment, the carriage is configured to be rotated from a first position in which the at least one thread engaging portions are engaged with threads on the drive shaft to a second, slidable position, in which the at least one thread engaging portions are not engaged with the threads of the drive shaft. The tensioning tool can further comprise a drive shaft seat in which a first end of the drive shaft is seated, a spring that compresses between the drive shaft seat of and the tool body, and a removable handle connected to a second end of the drive shaft distal from the first end.
The foregoing specification and accompanying figures are for the purpose of teaching those skilled in the art the manner of carrying out the disclosure and should be regarded in an illustrative rather than a restrictive sense. As one skilled in the art can appreciate, embodiments disclosed herein can be modified or otherwise implemented in many ways without departing from the spirit and scope of the disclosure and all such modifications and implementations are intended to be included within the scope of the disclosure as set forth in the claims below.
Claims
1. A tensioning tool providing continuous control of conformable ligature tension, comprising:
- a tool body defining a slot;
- a connection portion shaped to at least abut a ligature capturing element;
- a threaded drive shaft running through at least a portion of the tool body;
- a carriage movable along the slot, the carriage defining a drive shaft passage having at least one thread engaging portion to engage threads on the drive shaft and wherein the drive shaft passes through the drive shaft passage; and
- a tensioning member coupled to the carriage;
- wherein the carriage is configured to be rotated from a first position in which the at least one thread engaging portion is engaged with threads on the drive shaft to a second, slidable position, in which the at least one thread engaging portion is not engaged with the threads of the drive shaft;
- wherein rotation of the drive shaft causes the carriage to move towards or away from the connection portion.
2. The tensioning tool of claim 1, further comprising:
- a drive shaft seat in which a first end of the drive shaft is seated;
- a spring that compresses between the drive shaft seat and the tool body, wherein the first end is an end proximate the connection portion.
3. The tensioning tool of claim 2, further comprising:
- one or more markings on the tool body that indicate an amount of compression of the spring.
4. The tensioning tool of claim 1, further comprising:
- a detachable handle connected to the drive shaft proximate to a second end that is distal from the first end.
5. The tensioning tool of claim 1, wherein the drive shaft passage includes a first thread engaging portion at a first end of the drive shaft passage, a second thread engaging portion at a second end of the drive shaft passage, and a non-threaded portion positioned between the first thread engaging portion and the second thread engaging portion.
6. The tensioning tool of claim 5, wherein the first thread engaging portion and the second thread engaging portion are located on opposing sides of the drive shaft passage.
7. The tensioning tool of claim 1, wherein the tensioning member is a post extending from the carriage.
8. The tensioning tool of claim 7, wherein the post is configured to receive a loop of a conformable ligature therearound.
9. The tensioning tool of claim 1, wherein the tool body extends through the carriage with a portion of the carriage including the drive shaft passage extending into the slot for receiving the drive shaft therethrough.
10. A tensioning tool for applying tension to a conformable ligature of a bone fixing system, the tension tool comprising:
- an elongate tool body having a first end and a second end;
- a threaded drive shaft extending along at least a portion of the tool body;
- a connection portion positioned at the second end of the elongate tool body shaped to engage a ligature capturing element of the bone fixing system; and
- a carriage movable along the elongate tool body to selectively apply tension to the conformable ligature via movement of the carriage;
- the carriage defining a drive shaft passage through which the drive shaft extends through, the drive shaft passage having at least one thread engaging portion configured to engage threads on the drive shaft;
- wherein the carriage is configured to be actuated between a first position and a second position; and
- wherein in the first position the at least one thread engaging portion is engaged with threads on the drive shaft such that rotation of the drive shaft causes the carriage to move along the elongate tool body, and in the second position the at least one thread engaging portion is not engaged with the threads of the drive shaft such that the carriage is freely movable along the elongate tool body without rotation of drive shaft.
11. The tensioning tool of claim 10, wherein the drive shaft passage includes a first thread engaging portion at a first end of the drive shaft passage, a second thread engaging portion at a second end of the drive shaft passage, and a non-threaded portion positioned between the first thread engaging portion and the second thread engaging portion.
12. The tensioning tool of claim 11, wherein the first thread engaging portion and the second thread engaging portion are located on opposing sides of the drive shaft passage.
13. The tensioning tool of claim 10, further comprising a tensioning member extending from the carriage configured to receive a loop of a conformable ligature therearound.
14. The tensioning tool of claim 10, wherein the carriage is actuated between the first position and the second position by rotating the carriage about an axis generally perpendicular to a longitudinal axis of the drive shaft.
15. The tensioning tool of claim 14, wherein the at least one thread engaging portion is moved into engagement with threads of the drive shaft as the carriage is rotated to the first position.
16. The tensioning tool of claim 15, wherein the at least one thread engaging portion is moved out of engagement with threads of the drive shaft as the carriage is rotated to the second position.
17. The tensioning tool of claim 10, wherein the drive shaft extends through at least a portion of the elongate tool body.
18. The tensioning tool of claim 17, wherein the elongate tool body includes an elongate slot along which the carriage travels.
19. The tensioning tool of claim 18, wherein the elongate tool body extends through the carriage with a portion of the carriage including the drive shaft passage extending into the slot for receiving the drive shaft therethrough.
Type: Application
Filed: Feb 9, 2012
Publication Date: Jun 7, 2012
Applicant: Zimmer Spine S.A.S. (Bordeaux)
Inventors: Karl Pierre Belliard (La Membrolle), Gilles Larroque-Lahitette (Lagor), Marion Jeanne Sophie Delclaud (Pau), Jean-Luc Albert Paul Jouve (Marseille)
Application Number: 13/369,824