Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
2002-04-24
2004-08-03
Philogene, Pedro (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
C606S075000
Reexamination Certificate
active
06770075
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to apparatus and methods for treating spinal disorders, and more particularly to spinal fixation systems that may be secured between adjacent anchor screw assemblies, and methods for stabilizing, adjusting, or otherwise fixing adjacent vertebrae using such spinal fixation systems.
BACKGROUND
Various systems and methods have been suggested for treating spinal disorders, such as degenerative discs, stenosis, trauma, scoliosis, kyphosis, or spondylolisthesis. For example, U.S. Pat. No. 5,545,166, naming the same inventor as the present application, discloses a spinal fixation system that includes a plurality of anchor screws, clamp assemblies, pivot blocks, clamp blocks, and rods that are implanted along a patient's spine to fix two or more adjacent vertebrae relative to one another. The system generally includes a swing bolt anchor screw, a pivot block receivable on the swing bolt, and a clamp block receiving a rod therethrough that is pivotally attachable to the pivot block. In addition, the system includes one or more fixed anchor screws, and clamp assemblies for receiving the rod therein. The clamp assemblies and pivot block are receivable on the anchor screws by spindles that thread along a threaded portion of the anchor screws.
During use, vertebrae to be treated are surgically exposed, and an arrangement of anchor screws and clamp accessories are selected. For example, a fixed anchor screw may be screwed into each of the vertebrae on either side of a first vertebra. A rod is selected that may extend between the fixed anchor screws and that may be bent to conform to the shape of the anatomy encountered. The rod is inserted through a loose clamp block, and the rod is placed in clamp assemblies that are received over the fixed anchor screws.
A swing bolt anchor screw is then screwed into the first vertebra adjacent the rod, and a pivot block is received on the swing bolt screw. The clamp block and/or pivot block are adjusted such that the clamp block may be engaged with a pivot on the pivot block. A set screw may then be screwed into the clamp block to secure the clamp block to the pivot. A pair of set screws are also screwed into the clamp block to secure the rod within the clamp block. Preferably, a pair of such systems are implanted on either side of the vertebrae.
During the procedure, it may be desirable to adjust the vertebrae relative to one another. Once the system(s) is(are) connected as described above, the set screws may be loosened and the rod(s), clamp block(s), and/or pivot block(s) may be adjusted, e.g., by moving the spindle(s) to adjust the height of the pivot block(s) and/or clamp assemblies on the anchor screws, by pivoting the swing bolt anchor screw(s), and/or pivoting the clamp block(s) relative to the pivot block(s). Once the vertebrae have been moved into a desired position, the set screws may be tightened, and the spindles secured in position by crimping the walls surrounding the spindles.
An advantage of this system is that the swing bolt anchor screw, pivot block, and clamp block arrangement allows the system to be adjusted about two axes, i.e., the axis of the swing bolt anchor screw and the axis of the pivot on the pivot block. However, because the system of the '166 patent is polyaxial, i.e., may pivot about multiple axes, there is greater risk of the system coming out of alignment when the patient resumes normal physical activity.
This system is also very complicated, involving six parts, including three set screws, that are mounted on each swing bolt anchor screw. In addition, because the swing bolt is threaded, an intricate spindle device is required in order to allow the pivot block and clamp assemblies to be threaded onto the swing bolt, and still control their orientation about the axis of the swing bolt. Thus, because of its complexity and many intricate parts, this system may be expensive to manufacture and/or difficult to implant.
Accordingly, apparatus and methods for stabilizing, adjusting, and/or fixing vertebrae would be considered useful.
SUMMARY OF THE INVENTION
The present invention is directed to spinal fixation systems that may be secured between adjacent anchor screw assembles, e.g., to rods extending between the anchor screw assemblies, and to methods for stabilizing, adjusting, or otherwise fixing adjacent vertebrae using such spinal fixation systems.
In accordance with one aspect of the present invention, a spinal fixation system is provided that includes a first anchor screw assembly including a first passage and a first screw, the first screw having a threaded portion configured to be screwed into a first vertebra, and a second anchor screw assembly including a second passage and a second screw, the second screw having a threaded portion configured to be screwed into a second vertebra adjacent the first vertebra. In an exemplary embodiment, one or both of the anchor screw assemblies may include a saddle or clamp assembly receivable on the respective screw, each saddle assembly including a rod passage therethrough defining the first and second passages. Preferably, the saddle assemblies include upper and lower saddles or clamp portions that may together define the rod passage.
A rod or other elongate member is receivable in the first and second passages, the elongate member including an exposed portion extending between the first and second anchor screw assemblies. A spacer is securable on the exposed portion of the elongate member, the spacer having a length substantially similar to a length of the exposed portion of the elongate member for preventing the first and second anchor screw assemblies from moving towards one another.
In accordance with another aspect of the present invention, a kit is provided for stabilizing vertebrae relative to one another. Generally, the kit includes one or more substantially rigid rods, and a plurality of “C” shaped spacers having a plurality of lengths, the spacers including opposing edges defining a pocket therebetween for receiving the one or more rods therein. The kit may also include a plurality of anchor screw assemblies, the anchor screw assemblies including anchor screws and a plurality of clamp assemblies for receiving the one or more rods therein.
Optionally, the kit may also include a tool for crimping at least a portion of the opposing edges of the spacers around the one or more rods to secure the spacers to the rods. In another option, the kit may include an apparatus for bending the one or more rods, e.g., to conform substantially to a natural curvature of a patient's spinal column being treated.
In accordance with still another aspect of the present invention, a method is provided for stabilizing vertebrae relative to one another, the vertebrae being disposed adjacent one another along a central spinal axis. A first anchor screw may be screwed into a first vertebra, and a second anchor screw may be screwed into a second vertebra adjacent the first vertebra. A rod or other elongate member may be secured between the first and second anchor screws, e.g., using clamp assemblies, thereby fixing a relative distance of the first and second vertebrae.
A spacer, e.g., a “C” shaped clip, may be secured or otherwise placed on the elongate member, e.g., by crimping the spacer around the elongate member. Preferably, the spacer extends substantially an entire length of the elongate member that is exposed between the first and the second anchor screws to prevent the first and second anchor from moving towards one another. For example, the spacer may abut clamp assemblies on the first and second anchor screws, thereby preventing the clamp assemblies, and consequently the anchor screws, from moving substantially towards one another. One or both of the clamp assemblies may have a tapered side portion to enhance abutment of the spacer and the clamp assemblies if the elongate member is bent, e.g., to conform to the natural curvature of the anatomy encountered.
In accordance with yet another aspect of the present inven
Orrick Herrington & Sutcliffe LLP
Philogene Pedro
LandOfFree
Spinal fixation apparatus with enhanced axial support and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spinal fixation apparatus with enhanced axial support and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spinal fixation apparatus with enhanced axial support and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3339494