Patent Application
20060241641
The repair and reconstruction of bony structures is sometimes accomplished by directly fixing adjacent bony portions to each other, such as by a plate. In other instances, bone growth inducing material can be introduced between the adjacent bony portions, which over time results in a solid bony connection. In some instances, the adjacent bony portions are not sufficiently strong to maintain their patency as the bone heals or the bone grows between the adjacent structures through the bone growth inducing material. In these instances, grafts, cages, artificial joints and other implants have been provided to engage the adjacent bony structures to provide additional stability.
One problem, among others, with such implants is associated with positioning the implant in the space between adjacent bony portions. Insertion can be difficult or time consuming if the bony portions are spaced too close together, or if the adjacent tissue, nerves or vasculature impedes access to or placement of the implant in the space between the bony portions. Furthermore, maintenance of distraction of the space during insertion of the implant requires additional instruments in the space or in the operative approach to the space which can make the procedure more invasive and impede access and visibility during implant insertion.
The invention provides instruments that facilitate placement of an artificial disc and other implants and instruments between adjacent vertebrae of a spinal column.
According to one aspect, there is provided an instrument for positioning an implant in a space between adjacent vertebrae. The instrument includes a housing and a pair of opposing guide members coupled to the housing. Each of the guide members includes a body with an outer surface and an opposite guide surface and an elongated slot opening therebetween. The slot extends along and opens at a distal end of the respective guide member. The distal ends of the guide members are positionable in the space between vertebrae. The instrument also includes a spreader positioned between the pair of guide members. The spreader includes a central body and with a pair of oppositely extending wings. Each wing includes a body slidingly received in a slot of a corresponding one of the pair of guide members and an enlarged outer end. A drive member is coupled to the spreader and operable to forwardly advance the spreader toward the distal ends of the guide members.
In another aspect, there is provided a system for stabilizing a spinal disc space while preserving motion capabilities of the vertebrae adjacent the disc space. The system includes a pair of opposing guide members extending from a handle assembly. Each of the pair of guide members includes a body with an outer surface and an opposite guide surface and a spreader positioned between the pair of guide members. An artificial disc implant includes upper and lower plate members and with an articulating member therebetween. The implant is positionable between the guide surfaces forwardly of and in engagement with the spreader with at least one anchoring member of the implant extending through at least one of the guide members. The system also includes a drive member coupled to the spreader and operable to forwardly advance the spreader and the artificially disc implant toward distal ends of the guide members.
According to a further aspect, a method for inserting an implant in a space between adjacent vertebrae is provided. The method employs an instrument having a housing and a pair of opposing guide members coupled to the housing. The guide members each include an elongate central slot extending therealong and opening at a distal end of the guide member. The instrument also includes a spreader positioned between the pair of guide members and a drive member coupled to the spreader and extending though the housing. The method includes: providing an implant inserter; pivoting at least one of the pair of guide members away from the other of the pair of guide members; positioning an implant on the other of the pair of guide members and forwardly of the spreader, the implant including a first anchoring member extending through the slot of the other guide member; and pivoting the at least one guide member toward the other guide member to receive a second anchoring member of the implant through the slot of the at least one guide member.
These and other aspects can be discerned from the following written description and accompanying figures.
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the illustrated embodiments thereof and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any such alterations and further modifications in the invention, and any such further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates.
An instrument is provided for inserting artificial disc and other implants into a space between adjacent bony portions to support the adjacent bony portions. The inserter instrument can be used with any type of bone support implant, such as artificial joints, spacer devices, and fusion devices, for example. The implants can be made from bone material or any suitable biocompatible metal, plastic, or other material. The implants can also be made from combinations of materials, and include multiple components fixed to or movable relative to one another. In one application, the inserter instrument is employed in spinal surgical procedures for inserting an artificial implant in the disc space between adjacent vertebrae. The inserter instrument can also be employed to guide instruments that prepare the vertebrae to receive the implant.
For example, in the illustrated embodiments of
In
The proximal ends of guide members 100, 120 are pivotally attached to housing 22, facilitating loading of the implant 160 and placement of the distal ends of guide members 100, 120 adjacent one another for positioning in the spinal disc space. As indicated in
Further details of the assembly of inserter instrument 20 will be discussed with further reference to
It should be understood that the terms “upper” and “lower” refer to the orientation of the elements of the instruments in the Figures as shown in an operative approach to the space between adjacent bony portions. The instruments can be rotated or repositioned such that, for example, the lower fingers extend upwardly and guide member 100 is positioned above guide member 120.
In
In another embodiment, drive member 40 can include a ratchet mechanism. A ratchet bar can be provided along shaft 42, which is moved linearly in housing 22 to distally advance spreader 60 between guide members 100, 120. A handheld pistol grip-like handle with a trigger, a threaded screw with a thumbwheel thereabout, or other suitable handle can be provided to effect the linear movement of the ratchet bar. A catch mechanism, either in the handle or housing, can maintain the distal positioning of the ratchet bar until it is released, allowing the ratchet bar to be linearly and proximally moved by actuating the trigger mechanism.
In
Spreader 60 is movable with drive member 40 from a proximal position shown in
Referring to
The ability to quickly disassemble guide members 100, 120 allows inserter instrument 20 to be cleaned and sterilized after the surgical procedure is completed. It further allows guide members 100, 120 to be provided in a set of guide members for use with a common housing, drive member and implant holder. For example, the guide members in the set can include various lengths, widths, or abutment member configurations from which the surgeon may select during surgery. Other embodiments contemplated guide members that are not removably coupled to housing 26, or guide members that are not easily removed for cleaning purposes.
Guide members 100, 120 extend distally from housing 22, and define a path for insertion of an implant between the adjacent bony portions, such as vertebrae 220, 222. As shown in
Similarly, guide member 120 includes a body 134 extending from a proximal end 130 to a distal end 126. Body 134 can be provided with an elongated guide slot 122 extending therethrough along a central axis of body 134. Guide slot 122 opens along a guide surface 121 and opposite outer surface 123 of body 134. Guide slot 122 extends from a location adjacent proximal end 130 to a location through distal end 126. Guide slot 122 includes an enlarged proximal end opening 128 for passage of the enlarged outer end of upper wing 64. The remaining proximal portion of guide slot 122 is sized to slidingly receive the body 65 of upper wing 64, but prevents passage of the enlarged outer end of wing 64 therethrough.
Guide member 100 can be provided with an abutment member 104 adjacent distal end 106 projecting from outer surface 103 for contacting the adjacent bony structure to limit the insertion depth of guide member 100 into the space between the adjacent bony portions. A support portion 107 of guide member 100 extends distally from abutment member 104 and into the space between the adjacent bony portions, forming an extension of and being co-planar with guide surface 101 and outer surface 103. Guide member 120 can be provided with an abutment member 124 projecting from outer surface 123 adjacent distal end 126 for contacting the adjacent bony portion to limit the insertion depth of guide member 120 into the space between the adjacent bony portions. A support portion 127 extends distally from abutment member 124 and into the space between the adjacent bony portions, forming an extension of and being co-planar with guide surface 121 and outer surface 123.
When assembled to housing 22, the guide surfaces 101, 121 of guide members 100, 120 are oriented toward one another. Support portions 107, 127 can extend along an adjacent surface of the adjacent bony portion to facilitate insertion of the implant 160 into the space between the adjacent bony portions. Support portions 107, 127 also contact the adjacent bony portions to distribute a spreading or distraction force thereto. The spreading or distraction force can be applied to the adjacent bony portions by separating guide members 100, 120 as the implant 160 and spreader 60 are distally advanced between guide members 100, 120. Support portions 107, 127 further protect the adjacent vertebral endplate as implant 160 is positioned in the space between the adjacent bony portions, and facilitate insertion of implant 160 in the desired position in the space between the adjacent bony portions.
In one embodiment, it is contemplated that implant 160 is selected from a set of implants having various heights and or angulation between its upper and lower surfaces. The implant of the appropriate height can be selected to provide a height that corresponds to a desired restored disc space height when implanted. If vertebral motion is desired, implant 160 can be an artificial disc implant. In the illustrated embodiment of
Implant 160 further includes an upper anchoring member 168 extending from upper plate 162, and a lower anchoring member 170 extending from lower plate 164. Anchoring members 168, 170 are engageable to a respective adjacent vertebra to maintain a positioning of implant 160 in the disc space 224. Anchoring members 168, 170 may be in the form of elongated blades that are alignable along and positionable through the adjacent slots 122, 102 of guide members 120, 100. Anchoring members 168, 170 are movable along guide members 120, 100 and into engagement with the adjacent vertebrae as implant 160 is positioned in disc space 160.
Implant 160 is positionable between guide members 100, 120 when one of the guide members is moved away from the other, as shown in
Distal ends 106, 126 of guide members 100, 120 can be positioned adjacent one another when implant 160 and spreader 60 are adjacent the proximal ends of guide members 100, 120. This provides a low profile arrangement that allows positioning of support portions 107, 127 in the disc space 224, even if the disc space has collapsed due to removal of distraction. Abutment members 104, 124 are positionable in contact with the adjacent vertebral bodies, preventing over insertion of guide members 100, 120 into the disc space. In the illustrated embodiment, abutment members 104, 124 are orthogonally oriented to the central axis of the guide members, aligning guide members 100, 120 for implant insertion approach along or parallel to, for example, the sagittal plane in an anterior approaches to spinal procedures. In another embodiment, abutment members are obliquely oriented to the central longitudinal axis of guide members 104, 124 to facilitate placement of guide members 100, 120 in an approach obliquely oriented to, for example, the sagittal plane in spinal procedures.
Implant 160 is advanced distally between guide members 100, 120 by rotating drive member 40 within housing 22, distally advancing drive member 40 and thus spreader 60 and implant 160 along guide members 100, 120. As implant 160 and spreader 60 are distally advanced, the guide members 100, 120 are spread apart or separated from one another. This separation causes support portions 107, 127 to separate and exert a distraction force on the vertebral endplates, separating vertebrae 220, 222 a sufficient distance to accommodate implant 160 therebetween.
In
Slots 102, 122 extend through abutment members 104, 124, providing an avenue for further advancement of spreader 60 and implant 160 relative to guide members 100, 120. Drive member 40 can be rotated to position wings 64, 66 in contact with vertebrae 220, 222. As driver member 40 is further manipulated, wings 64, 66 and act on the vertebrae to completely displace spreader 60 to distal ends of slots 102, 122, as shown in
As implant 160 is guided between guide members 100, 120 into the space between the adjacent bony portions, the positioning of implant 160 is controlled in the cephalad/caudal directions by contact of guide surfaces 101, 121 with implant 160. Guide surfaces 101, 121 align implant 160 with the space between the adjacent bony portions. The lateral positioning of implant 160 along guide members 100, 120 is controlled by engagement of implant 160 with engaging members 76 so that implant 160 does not slip out from between guide members 100, 120, where it might contact or damage tissue, nerves, vasculature or other tissue structures adjacent the bony portions on the approach to the space therebetween. Anchoring members 168, 170 extending through slots 122, 102 also maintaining implant 106 between the guide members. Anchoring members 168, 170 are driven into the respective vertebrae 220, 222 to secure implant 160 in position between vertebrae 220, 222.
Inserter instrument 20 can also be employed as a guide to guide placement of instruments to prepare vertebrae 220, 222 to receive implant 160. One example of a preparation instrument is a chisel 300 shown in
Chisel 300 is a center cut chisel with a distal cutting member 302 and an abutment member 304 at a distal end thereof. Chisel 300 further includes proximally extending legs 306 extending from abutment member 304. Legs 306 include angled portions 307 in a diverging relation to one another and parallel portions 308 extending proximally from angled portions 307. An impactor 320 is positionable between parallel portions 308, and movable into contact with the junction of angled portions 307 to apply impaction forces to chisel 300.
Impactor 320 includes an impactor head 322 and a shaft 324 to facilitate transfer of the impaction forces. Impactor head 322 can include a distally tapered distal end to fit between angled portions 307 and a proximal portion slidably received between parallel portions 308.
In use, chisel 300 is positioned on and guided on the guide members, such as guide member 120′. Guide member 120′ is similar to guide member 120, but includes rails 125′ extending from the lateral sides thereof that form inwardly facing slots 127′. Rails 125′ extend along a portion of the length of guide member 120′, and allow chisel 300 to be end loaded into rails 125′ along the outer surface of guide member 120′. Other embodiments contemplate other interfitting arrangements between the chisel and guide member, such as a slot or groove formed in any portion of the guide member that can receive a portion of the chisel.
The vertebrae can be distracted by advancing a spreader without wings or an implant positioned forwardly thereof to a location adjacent support portions 107, 127. Parallel portions 308 of legs 306 include extensions 312 that are positioned in respective ones of the slots 127′ formed by rails 125′ of guide member 120′. This dovetail arrangement slidably secures chisel 300 on guide member 120′ with blade 302 aligned with slot 122′. Rails 125′ further guide chisel 300 distally along guide member 120′ to insert blade 302 into vertebra 220 along a path aligned with slot 122′. Impactor 320 may be employed as needed to deliver impaction forces to facilitate forming a chisel cut 221′ in the bone of the vertebral body, as shown in
After forming the chisel cuts in vertebrae 220, 222, implant 160 can be loaded between the guide members with anchoring members 168, 170 extending through slots of the guide member as discussed above. The guide members 100, 120 are aligned with the disc space, and implant 160 is guided along guide members to position implant 160 between the vertebrae with anchoring members 168, 170 received in the previously formed chisel cuts. The guide members can then be withdrawn proximally by passing the distal end opening of each of the guide members proximally along the respective anchoring members 168, 170 engaged to the vertebrae 220, 222.
It is also contemplated that the inserter instrument 20 can be engaged to one or more of the vertebrae 220, 222 or other structure to maintain a positioning of inserter instrument 20 as the implant is positioned between the vertebrae and/or as one or more of the vertebrae 220, 222 are prepared to receive the implant with the chisel or other instrument. For example, as the implant is positioned between the vertebrae, the anchoring members 168, 170 or some other portion of the implant may meet resistance to distal movement upon contact with the bony structure of the vertebrae, and such resistance may tend to displace inserter instrument 20 proximally as increased force is applied to overcome the resistance. Various attachment arrangements are contemplated, examples of which are shown in
In one arrangement, an external attachment arrangement 200 is provided that includes an attachment member 204 connectable to, for example, housing 22 and a support structure 202. Support structure 202 can be a surgical table, stand, wall, floor or other device that provides sufficient stability to maintain the positioning of inserter instrument 20 during the procedure. Attachment member 204 can be an arm, link, cable, bracket, support system, or other device that extends between and rigidly links inserter instrument 20 to support structure 202 at least when forces are applied that tend to displace inserter instrument 20 away from vertebrae 220. 222. Attachment member 204 could be attached to any suitable portion of inserter instrument 20.
In another arrangement, at least one of the support portions 107, 127 of guide members 100, 120 includes an attachment member 192, 194 that is positionable through the endplate of an adjacent one of the vertebrae 222, 220. Attachment members 192, 194 may be provided on one or both of the guide members 100, 120. Attachment members 192, 194 may comprise one or more spikes, teeth, ridges, or other structure that penetrates the respective adjacent vertebral endplate sufficiently to resist pull-out forces that might be encountered.
In another arrangement, at least one of the abutment members 104′, 124′ of guide members 100, 120 includes an attachment member 150, 152 that is positionable therethrough and engageable to an adjacent one of the vertebrae 222, 220. Attachment members 150, 152 may be provided on one or both of the guide members 100, 120. The respective abutment members 104′, 124′ may be provided with a hole to receive the attachment member, and may be provided with a sufficient height along the respective vertebra 222, 220 to allow placement and engagement of the respective attachment member 150, 152 therethrough. Attachment members 150, 152 may each comprise one or more bone screws, spikes, anchors, bolts, teeth, barbs, staples, suture anchor, suture, cable or other suitable attachment device that engages the respective adjacent vertebra sufficiently to resist pull-out forces that might be encountered.
In yet another embodiment, an attachment arrangement 180 includes a first securing member 182, a second securing member 184 and an attachment member 186 extending therebetween. Attachment arrangement 180 can be provided for one or both of the vertebrae 220, 222. The securing members 182, 184 provide a location for securing the attachment member 186 to the guide member 120 and vertebra 220, respectively. Securing members may be any type of fastener, block, or other member or location to which attachment member 186 can be engaged. Attachment member 186 can be a wire, cable, suture, cord, link, bar, strut or other device with sufficient tensile strength to resist pull-out forces that might be encountered.
The instruments discussed herein can protect the adjacent tissue and vasculature from the implant during insertion by preventing the implant 160 and spreader 60 from twisting and moving outside the guide path during insertion. The instruments further protect the bony structures between which the implant is inserted during insertion, and facilitate withdrawal of the implant after it is positioned in the space between the bony structures. Furthermore, the instruments can be adapted to guide insertion of implants of various heights, and to provide varying spacing between adjacent bony portions customized to fit the particular implant. The instruments include a low profile in the operative space, facilitating visualization and placement of additional instruments in the operative approach to the bony structures. The instruments are simple to disassemble, allowing for cleaning and use of selected guide members from a set of guide members, providing convenience and flexibility to the surgeon during the surgical procedure.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. All changes and modifications that come within the spirit of the invention are desired to be protected.
