This invention relates to a tool for use injecting bone replacement material into a cavity within a bone, especially when the cavity includes a bag which is to be inflated within the cavity.
U.S. Pat. No. 5,549,679 issued Aug. 20, 1996 and U.S. Pat. No. 5,571,189 which issued Nov. 5, 1996 disclose an expandable fabric bag and method for stabilizing a spinal motion segment. In those patents, a damaged disc is reamed out and an expandable fabric bag is inserted into the cavity thus formed. Bone graft material is then inserted into the bag to fill and expand the bag such that the filled bag will take the place of the reamed out disc. Over time, the material within the bag will cause stabilization by either fibrous or bony fusion or a combination of these between the adjacent vertebrae. The bag filling is through an opening which is closed off after filling.
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. sctn. 1.56(a) exists.
The invention provides a tool which dramatically increases the distraction forces within an expandable fabric bag held within a reamed out disc. Distraction consists of a force that is perpendicular to the long axis of the injection tube, thereby producing distraction or increased separation distance between the bony structures that are perpendicular to the long axis of the injection tube. This allows the spacing between the vertebrae to be adjusted by inflating the bag as desired. The tool may be used in connection with any surgical application in which graft material is to be deployed and is not limited to use in connection with discs or where bags are required.
A detailed description of the invention is hereafter described with specific reference being made to the drawings in which:
U.S. Pat. Nos. 5,571,189 and 5,549,679 are incorporated herein by reference. They show an expandable fabric bag which is to be inflated within a reamed out disc space by introduction of bone replacement material through the bag opening. As shown in
The bone replacement material might be one or more of the following, or any other biocompatible material judged to have the desired physiologic response:
A) Morselized bone graft, cortical, cancellous, or cortico-cancellous, including autograft, allograft, or xenograft.
B) Any bone graft substitute or combination of bone graft substitutes, or combinations of bone graft and bone graft substitutes, or bone inducing substances, including but not limited to:
Hydroxyapatite
Bone morphogenic protein
Calcified or decalcified bone derivative
C) Bone cements, such as ceramic and polymethylmethacrylate bone cements.
The inventive fill tool 18 of
As shown in
The forces during filling provided by the device are perpendicular to the axis of the tube to stop tear through, to prevent the tube from being pushed out during filling, to direct the flow to get the distraction desired and to reduce the overall forces required. A straight tube with an open end has no distraction forces perpendicular to the tube and merely lays a long column of replacement material that needs to buckle before more material can be extruded from the tube. The inventive device breaks up the column of replacement material in the tube by cantilever forces. A straight tube with an open end creates a rigid bar of replacement material that can break a containment bag or damage body structures they press against or cause the tube to be ejected from the neck of the bag or body cavity opening.
Tests show a dramatic increase in distraction forces for filling a bag with a tool of the invention in comparison to a fill tool which has an opening in line with its longitudinal axis. Since bone replacement material tends to become quite rigid under pressure, injection of bone replacement material into the bag at an angle relative to the longitudinal axis of the fill tube allows the bag to inflate and create forces which are not directed to eject the fill tool.
If the internal diameter of the tube is D, the length of the side opening 30 is preferably between about 11/2 to 3D. If the side opening 30 length is only 1D or smaller, harder pushing is required and packing of the material may result in the tube. The distal end of the tube 40 towards the apex 42 is also preferably angled to direct the flow and to break down any material that has packed back into more discrete pieces. The end adjacent the apex 42 of the tool may be completely closed or open up to 1/2D which still provides good side direction of product.
As may be seen in
The tapered distal end 64 of the tool 60 is sized to enlarge the opening 54 to allow passage of the tool 60 into the interior 52 by pushing aside the various fibers 56 as may best be seen in
The extent of tool penetration into the band interior 52 must be sufficient to allow the side opening 66 to be fully contained within the band interior 52. The tool 60 may include more than one side opening 66.
As shown in
While this invention may be embodied in many different forms, there are shown in the drawings and described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. For example, the inventive device and methods may be used whenever replacement material needs to be directed into a defined location and not just when a bag is to be filled within a disc cavity.
This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.
This application is a continuation of U.S. patent application Ser. No. 09/608,079, filed Jun. 30, 2000 (abandoned), which is a continuation of U.S. patent application Ser. No. 09/738,726, filed Dec. 15, 2000, now U.S. Pat. No. 7,025,771, issued Apr. 11, 2006.
Number | Date | Country | |
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Parent | 11402222 | Apr 2006 | US |
Child | 12607663 | US | |
Parent | 09608079 | Jun 2000 | US |
Child | 09738726 | US |
Number | Date | Country | |
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Parent | 09738726 | Dec 2000 | US |
Child | 11402222 | US |