Insertion instruments and method for delivering a vertebral body spacer

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The present invention relates to a spacer insertion instrument, more particularly to an instrument for inserting a spacer into an anterior portion of the spine. A method is also provided for delivering a vertebrae body spacer to the spine.

Instruments for inserting spacers into a spine are known. See, for example U.S. Pat. No. 5,431,658 to Moskovich, which is incorporated herein by reference.

According to the present invention a spacer-insertion instrument is provided for delivering a spacer to a spine. The spacer-insertion apparatus comprises a handle portion, a guide coupled to the handle portion, a shaft coupled to the handle portion and extending along the guide, and a tip coupled to the shaft. The tip includes an attachment end portion that is coupled to the shaft and opposing fingers for grasping the spacer. The fingers move relative to one another to grasp the spacer when the shaft is moved to actuate the fingers.

In preferred embodiments, the tip includes a central portion that extends between the attachment end portion and the fingers and includes a slot. The slot includes a closed end and an opposite open end adjacent to the fingers. In addition, each finger includes a fixed end coupled to the central portion and an opposite free end. The fixed ends cooperate with one another to define the open end of the slot.

Each finger also includes an interior surface and an exterior surface. The interior surfaces cooperate with one another to define a space sized to receive the spacer. The interior surfaces are generally concave in shape. In addition, each finger may be formed to include at least one tooth extending into the space in accordance with embodiments of the invention.

The handle portion of the spacer-insertion apparatus includes a grip and a trigger coupled to grip and to the shaft. The trigger is movable relative to the grip. Movement of the trigger toward the grip causes movement of the fingers, pressing the fixed end portions together. Thus, the fingers to move toward one another to couple the spacer therebetween. Additionally, the handle portion includes a lock coupled to the grip. The lock includes teeth that cooperate with the trigger to limit movement of the trigger away from the grip, but permit movement of the trigger toward the grip.

According to the present invention a vertebral body insertion kit is provided. The kit includes a spanner that has a handle portion with opposite ends and a notched portion formed at one of the ends. The notched portion has a pre-determined dimension and is sized for extension into a disc space formed in a spine. The kit also includes a spacer that has a dimension approximately equal to the dimension of the notched portion and a spacer-insertion apparatus. The spacer-insertion apparatus comprises a handle portion, a guide coupled to the handle portion, a shaft coupled to the handle portion and extending along the guide, and a tip coupled to the shaft. The tip includes an attachment end portion that is coupled to the shaft and opposing fingers movable relative to one another. The fingers are adapted to grasp the spacer when the shaft is moved relative to the guide.

In preferred embodiments, the kit includes a trial that has a rod and a disc portion coupled to the rod. The disc portion has a height approximately equal to the dimension of the spacer. In addition, the kit preferably includes a facilitator formed with two guides that cooperate to define a passageway therebetween. The spacer is formed for movement between the guides in the passageway. The facilitator also includes top and bottom plates coupled to the respective guides and a jack mechanism positioned to lie between the top and bottom plates.

A method for delivering a vertebral body spacer to a disc space formed in a spine between adjacent vertebral bodies is also provided in accordance with the present invention. The method includes the steps of selecting a spacer and providing a spacer-insertion apparatus having a handle portion, a shaft coupled to the handle portion, and a tip coupled to shaft, the tip including an attachment end portion coupled to the shaft and opposing fingers movable relative to one another. The method also includes placing the fingers of the spacer-insertion apparatus about the spacer and moving the fingers toward the spacer to couple the tip and the spacer together. Additionally, the method includes inserting the tip and the spacer into the disc space, moving the fingers away from the spacer to release the spacer within the disc space, and withdrawing the fingers from the disc space.

Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an anterior portion of a spine, an inter-vertebral spacer, and a vertebral body spacer and showing a portion of one disc removed from the spine to form a disc space and the inter-vertebral spacer sized for extension into the disc space;

FIG. 2 is a perspective view of a spanner extending into the disc space of FIG. 1;

FIG. 3 is a perspective view of the spanner of FIG. 2 in a raised position and showing the spanner including a notched portion that engages an anterior cortex of the vertebral body;

FIG. 4 is a perspective view of a trial, showing the trial including a rod and opposite disc portions formed thereon that are formed to be approximately the same size of the spacers;

FIG. 5 is a side view of a spacer-insertion apparatus in accordance with the present invention with portions broken away showing the apparatus including a handle portion, a guide coupled to the handle portion and defining a passageway, a shaft extending through the passageway and a tip coupled to the shaft and including fingers formed to grasp the spacers of FIG. 1;

FIG. 6 is an enlarged fragmentary view of the shaft and the tip of the spacer-insertion apparatus of FIG. 5 and the inter-vertebral spacer and showing the tip including an attachment end portion formed to couple shaft and the fingers cooperating to define a generally U-shaped space sized to receive the spacer;

FIG. 7 is an assembled top view with portions broken away of the guide, the shaft, the tip, and the spacer of FIG. 6 showing the shaft coupled to a threaded inner surface of the tip and showing the spacer positioned to lie within the U-shaped space;

FIG. 8 is a view similar to FIG. 7 following movement of the tip toward the guide pressing the fingers toward each other to couple the spacer-insertion apparatus and spacer together;

FIG. 9 is a perspective view of a tip in accordance with the present invention and a spacer including a side wall formed to include apertures and showing the tip including fingers each with an interior surface that cooperate to define a space sized to receive the spacer and a tooth extending from the interior surface into the disc space;

FIG. 10 is a top view with portions broken away of the tip and spacer of FIG. 9 showing the spacer in an attached position wherein the teeth of the fingers extend through the apertures and engage the side wall of the spacer to couple the spacer-insertion apparatus and spacer together;

FIG. 11 is a plan view of a tip in accordance with the present invention and an irregularly-shaped spacer and showing the tip including fingers each having an interior surface that cooperate to define a generally space sized to receive the spacer and spaced-apart teeth extending from the interior surface into the disc space to bite into the spacer;

FIG. 12 is a plan view of an adjuster configured to engage a spacer and guide placement of the spacer on a vertebral body;

FIG. 13 is a perspective view of a facilitator that is configured to allow for insertion of spacers and showing the facilitator including a pair of guides cooperating to define a passageway;

FIG. 14 is a side view of the facilitator of FIG. 13 in an expanded position with portions of the bone broken away, showing the trial of FIG. 4 positioned to lie in the passageway between the guides and, in phantom, the facilitator and the trial positioned to lie within the disc space;

FIG. 15 is a view similar to FIG. 14 showing the spacer-insertion apparatus of FIG. 5 extending through the passageway defined by the guides of the facilitator to position the spacer in the disc space; and

FIG. 16 is a perspective view of a facilitator in accordance with the present invention that is used for anterior procedures, showing the facilitator including top and bottom plates, a jack mechanism coupled to the top and bottom plates, and spaced apart guides coupled to the top and bottom plates.

DETAILED DESCRIPTION OF THE DRAWINGS

Insertion instruments 10 are provided in accordance with the present invention for delivering vertebral body spacers 12 to a spine 14 during disc-replacement or vertebral body replacement surgery. Instruments 10 permit a surgeon to place spacers 12 into an anterior portion 18 of spine 14. This placement may be done to replace an inter-vertebral disc 20, as shown by arrows 30, or to replace a vertebral body 22, as shown by arrows 32, or multiple versions of each. Instruments 10 include a spanner 34, a trial 36, a spacer-insertion apparatus 38, and a facilitator 40.

As shown in FIG. 1, spacers 12 include inter-vertebral spacer 16 and vertebral-body spacer 26. Spacers 16, 26 are constructed of titanium mesh. Spacers 16, 26 include an outer surface 13 and an inner surface 15 that define a cavity 25 sized to house bone (not shown) such that spacers 16, 26 fuse to spine 14 to where there will be generally no movement between the two to reduce a patient's pain. In addition, apertures 17 extend between outer and inner surfaces 13, 15. Instruments 10 are also suitable for use with other forms of spacers that are also used in anterior portion 18 of spine 14. Specifically, instruments 10 are suitable for use with spacers constructed in a variety of sizes and from a variety of metals, composites, tissue, or bone, or any other type of spacer designed to be placed into spine 14 as a spinal spacer.

Referring now to FIGS. 1-3, spine 14 includes anterior portion 18 and a posterior portion 24. In addition, spine 14 is constructed of seven cervical vertebral bodies 22, twelve thoracic vertebral bodies 22, and five lumber vertebral bodies 22. Instruments 10 of the present invention are configured to deliver spacers 12 to anterior portion 18 or posterior portion 24 of spine 14 whether it is cervical, thoracic or lumber. As shown in FIG. 1, spacers 12 that are delivered with instruments 10 in anterior portion 18 of spine 14 can be designed to replace either disc 20 or vertebral body 22.

Referring now to FIG. 2, spanner 34 aids the surgeon in determining the approximate size of spacer 12 that should be placed within disc space 28. In addition, spanner 34 may be placed within disc space 28 to jack open disc space 28, as shown in FIG. 4, so that surgeon can clean out remaining disc 20 within disc space 28 between vertebral bodies 22. Spanner 34 includes a handle portion 42 having opposite ends 44, 46 and notched portions 48, 50 extending from ends 44, 46 respectively. As best shown in FIG. 3, handle portion 42 of spanner 34 has a first dimension 52. Referring now to FIG. 2, notched portion 48 has a second dimension 54 that is less than first dimension 52.

Moreover, notched portion 50 has a third dimension 56 that is greater than second dimension 54 and less than first dimension 52.

As shown in FIG. 4, trial 36 mimics spacer 12 and aids the surgeon in assessing how a corresponding spacer 12 would fit into disc space 28. Trial 36 includes a rod 58 and disc portions 60, 62 on either end of rod 58. Disc portion 60 has a first height 64 and second disc portion 62 has a second height 66. Illustratively, second height 66 is less than first height 64. It is appreciated that disc portions 60, 62 may vary in height so as to mimic the size of various spacers. Disc portions 60, 62 also have a pre-determined diameter that may vary in size in accordance with the present invention. Thus, trial 36 enables a surgeon to check both the height and the diameter of disc space 28 to determine what height and diameter spacer 12 will fit in disc space 28 to engage the maximum amount of vertebral body 22. In addition, it is appreciated that trial 36 may be formed with only one disc 60 formed thereon to enable a surgeon to strike rod 58 and tap disc 60 into disc space 28.

Spacer-insertion apparatus 38 grips and delivers spacer 12 to spine 14. While only inter-vertebral spacer 16 will be discussed hereafter, it is understood that the description also applies to vertebral-body spacer 26. Instrument 38 includes a handle portion 68, a guide 70 extending from handle portion 68, a shaft 74 extending along the guide 70, and a tip 76 coupled to shaft 74 and formed to grasp spacer 16.

Referring now to FIG. 5, handle portion 68 includes a grip 90, a movable trigger 92, and a lock 94 coupled to grip 90. Grip 90 is stationary and formed to be grasped by a surgeon. Movable trigger 92 pivots relative to grip 90 and includes an upper end portion 110 and a lower end portion 118. Upper end portion 110 includes a grip portion 112 coupled to grip 90 by a pin 116 and a shaft portion 114 spaced apart from grip portion 112 and coupled to first end portion 78 of shaft 74. Lock 94 is coupled to grip 90 and formed to block movement of trigger 92 away from grip 90 during insertion of spacer 16 into spine 12. As shown in FIG. 5, lock 94 includes a first end portion 96 coupled to grip 90 an opposite second end portion 98, and an angled middle portion 100 extending between end portions 96, 98. Middle portion 100 of lock 94 has a generally vertical segment 102 and a generally horizontal segment 104 that meet at a joint 106. Teeth 108 extend from horizontal segment 104 adjacent to second end portion 98. Teeth are formed to cooperate with lower end portion 118 to permit movement of trigger 92 toward grip 90, as shown by arrow 120, and block movement of trigger 92 away from grip 90, as shown by arrow 119.

As shown in FIGS. 5-8, guide 70 of spacer-insertion apparatus 38 extends between handle portion 68 and tip 76. Guide 70 includes an inner end portion 78 coupled to handle portion 68 and an outer end portion 80 spaced-apart from inner end portion 78. A passageway 72 extends between inner and outer end portions 78, 80. Shaft 74 of spacer-insertion apparatus 38 extends through passageway 72 of guide 70 and includes a first end portion 82 coupled to handle portion 68, an opposite second end portion 84 spaced-apart from outer end portion 80 of guide 70, and a middle portion 86 extending between first and second end portions 82, 84. As shown in FIG. 6, second end portion 84 of shaft 74 includes threads 88 thereon.

It is understood that the length of guide 70 and shaft 74 will vary depending whether the surgeon selects an anterior or posterior approach for the surgery. Thus, spacer-insertion apparatus 38 of the present invention may be used with anterior or posterior approaches to the cervical, thoracic, or lumbar spine 14. Spacer-insertion apparatus 38 having a relatively short guide 70 and shaft 74 are used for the anterior cervical procedure. In the case of the anterior thoracic and anterior lumbar procedures, guide 70 and shaft 74 is longer than that used in the anterior cervical procedure and guide 70 has an increased diameter to provide strength. Finally, in the posterior thoracic or lumbar procedure, guide 70 and shaft 74 are sized in between guides 16 and shafts 20 used in the anterior cervical procedure and the anterior thoracic and anterior lumbar procedures.

As shown in FIGS. 5-8, tip 76 of spacer-insertion apparatus 38 is coupled to shaft 74 and permits the surgeon to effectively grip spacer 16. Referring now to FIG. 6, tip 76 includes an attachment end portion 124 formed to couple shaft 74, an opposite clamp end portion 126, and a central portion 128 that extends between attachment and clamp end portions 124, 126. Attachment end portion 124 is formed to define an opening into a cavity 136. Threads 134 extend about an inner surface 132 in cavity 136 to couple threads 88 of shaft 74. It is appreciated that attachment end portion 124 may be coupled to shaft 74 in a variety of manners and tip and shaft, may in fact, be formed as a unitary member.

Central portion 128 of tip 76 extends between attachment and clamp end portions 124, 126 and has an outer surface 130 sized for movement within passageway 72 of guide 70. In addition, as shown in FIGS. 6-8, central portion 128 includes a slot 138 extending through outer surface 130. Slot 138 has a closed end 142, an opposite open end 144 adjacent to clamp end 126, and a middle portion 146 extending between ends 142, 144. Middle portion 146 includes opposite sides 148, 150 that cooperate to define a pre-determined normal width 142 of slot 138. It is appreciated that normal width 140 of slot 138 may vary.

As shown in FIG. 6, clamp end portion 126 of tip 76 includes fingers 152, 154 extending from respective sides 148, 150 of slot 138. Each finger 152, 154 includes a fixed end portion 164 coupled to an outer end portion 162 of central portion 128 and an opposite free end 166. As best shown in FIG. 7, fixed end portions 164 cooperate to define open end 144 of slot 138. In addition, each finger 152, 154 includes an interior surface 158 and an exterior surface 159. Interior surfaces 158 cooperate to define a generally U-shaped space 168 sized to receive spacer 16 therein. Fingers 152, 154 are movable relative to one another and adapted to grasp spacer 16 when shaft 74 is moved toward handle portion 68 to actuate fingers 152, 154. It is appreciated that fingers 152, 154 may be moved together when shaft 74 is pushed, rotated, or otherwise moved relative to the guide 70 in accordance with the present disclosure. Interior surface 158 of fingers 152, 154 are configured to provide generally uniform contact between tip 76 and spacer 16. Spreading the force of contact of tip 76 over outer surface 13 of spacer 16 decreases the risk of spacer 16 deformation during implantation between vertebrae 22. It is appreciated that the dimensions of interior surfaces 158 of fingers 152, 154 may vary to accommodate spacers 12 of various sizes.

To assemble spacer-insertion apparatus 38 of the present invention, threaded second end portion 84 of shaft 74 is inserted into threaded cavity 136 of attachment end 124. Tip 76 is rotated until threads 88 of shaft 74 are coupled to threads 134. Shaft 74 is configured for use with a variety of tips 22 having fingers 152, 154 of various sizes. Thus, a kit is contemplated wherein spacer-insertion apparatus 38 includes various tips that are interchangeable with shaft 74.

For example, referring now to FIGS. 9 and 10, tip 276 is provided in accordance with the present invention. Tip 276 is formed similarly to tip 76 and like reference numerals will be used to denote like components. Tip 276 is configured for use with handle portion 68 and guide 70 to form a spacer-insertion instrument 238 in accordance with the present invention. Referring to FIG. 9, tip 276 includes opposing fingers 152, 154 as previously discussed. Each finger 152, 154 includes a tooth 278 extending outwardly from interior surface 158. Teeth 278 are generally triangular in shape and sized for extension through aperture 17 and engagement with edges 19 defining aperture 17 of spacer 16. As shown in FIG. 10, teeth 278 extend through apertures 17 and engage edges 19 to prevent spacer 16 from slidi