Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
2001-01-23
2003-04-29
Robert, Eduardo C. (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
Reexamination Certificate
active
06554836
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to intervertebral spinal surgery, and more particularly to surgical instrumentation and to a method for creating one or more spaces between adjacent vertebral bodies in which the space has a shape and vertebral surfaces adapted in size to receive an implant or implants to be implanted in the space, and the method of implanting those implants.
2. Description of the Prior Art
The spinal disc that resides between adjacent vertebral bodies maintains the spacing between those vertebral bodies and, in a healthy spine, allows for relative motion between the vertebrae. With disease and/or degeneration a disc may become painful and/or mechanically insufficient warranting surgical fusion across the affected disc. Where fusion is intended to occur between adjacent vertebral bodies of a patient's spine, the surgeon typically prepares an opening at the site of the intended fusion by removing some or all of the disc material that exists between the adjacent vertebral bodies to be fused. Because the outermost layers of bone of the vertebral endplate are relatively inert to new bone growth, the surgeon must work on the endplate to remove at least the outermost cell layers of bone to gain access to the blood-rich, vascular bone tissue within the vertebral body. In this manner, the vertebrae are prepared in a way that encourages new bone to grow onto or through an implant that is placed between the vertebrae. An implant or insert may or may not promote fusion of the adjacent vertebral bodies, may be an artificial spinal disc, may permit surface ingrowth, and may be made of bone or inert material, such as titanium. All of these examples and more are implants.
Present methods of forming this space between adjacent vertebrae generally include the use of one or more of the following: hand held biting and grasping instruments known as rongeurs; drills and drill guides; rotating burrs driven by a motor; and osteotomes, chisels, and scraping implements. Surgeons often prefer a drilling technique due to its being ease, quick, and accurate. Sometimes the vertebral endplate must be sacrificed as occurs when a drill is used to drill across the disc space and deeper into the vertebrae than the thickness of the endplate. Such a surgical procedure is typically used to prepare a space in the spine for an implant having a circular cross section and necessarily results in the loss of the hardest and strongest bone tissue of the vertebrae, the endplate, and thereby robs the vertebrae of that portion of its structure best suited to absorbing and supporting the loads placed on the spine by everyday activity. Where the surgeon chooses to forego drilling a large bore across the disc space in an attempt to preserve that good bone he must nevertheless use one of the above instruments to work upon the endplates of the adjacent vertebrae to access the vascular, cancellous bone that is capable of participating in the fusion and causing active bone growth, and also to attempt to obtain an appropriately shaped surface in the vertebral bodies to receive the implant, which means and method are unreliable for that purpose.
There exists therefore a need for an improved surgical instrumentation and a related method for providing a space that is non-circular in cross section, and preferably a substantially quadrilateral space across the height of a disc space and into the adjacent surfaces of the adjacent vertebral bodies while taking advantage of the safe, easy, and accurate technique of boring or drilling into the spine to form a space and to shape the adjacent endplates to receive implants not typically associated with boring techniques.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to permit the formation of a substantially quadrilateral space in a spine for inserting a spinal implant into a disc space between adjacent vertebral bodies.
Yet another object is to provide surgical instrumentation for preparing an interbody space to receive a spinal implant and a related method for working upon vertebral body endplates adjacent a disc space useful in any region of the human spine, specifically, the cervical, dorsal, or lumbar regions.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention comprises a surgical instrument set for use in spinal surgery for forming a substantially quadrilateral space in the spine for implanting a spinal implant into a disc space between adjacent vertebral bodies and the methods for doing so.
An embodiment of the present invention includes an instrument set including a spinal marker for marking a location on the spine. The marker has a shaft and a disc penetrating extension extending from the shaft for insertion into the disc space between adjacent vertebral bodies. The shaft may have any number of cross sections including rectangular and circular. The marker preferably includes a shoulder for abutting against the exterior of the adjacent vertebral bodies. The disc penetrating extension of the marker preferably is tapered to facilitate insertion into the disc space. The shaft of the marker has a proximal end and an opposite distal end oriented toward the spine. The shaft of the marker preferably includes a passage having a dye receiver at the proximal end of the shaft of the marker and at least one dye exit hole at the distal end of the shaft of the marker for marking the spine. The marker preferably includes means for coupling to a syringe.
The instrument set includes a guard having an opening for providing protected access to the disc space and the adjacent surfaces of the vertebral bodies adjacent the disc space and having a disc penetrating extension extending from the guard for insertion into the disc space between the adjacent vertebral bodies and for bearing against the adjacent vertebral endplates of the adjacent vertebral bodies. The guard may have two disc penetrating extensions extending from the guard and diametrically opposed to each other. The disc penetrating extensions preferably has a leading-edge that may include either of a pointed, tapered, radiused, chamfered, or wedge tipped shape to ease insertion of the extensions into the disc space. The guard preferably is adapted to conform at least in part to the exterior of the adjacent vertebral bodies. The guard may include a shoulder that conforms at least in part to the exterior of the adjacent vertebral bodies. The shoulder preferably curves to correspond to the external curvature of the adjacent vertebral bodies. The guard may further include means for engaging the adjacent vertebral bodies when in use. The guard includes a hollow shaft adapted to allow access through the hollow shaft to the disc space.
The instrument set further includes a guide for guiding a bone removal device. The guide has a shaft adapted for insertion into the guard. The guide includes means for guiding the formation of the substantially quadrilateral space across the height of the disc space and into the adjacent surfaces of the adjacent vertebral bodies. The guiding means preferably includes a plurality of guide bores. The plurality of guide bores may overlap one another. The plurality of guide bores may include three guide bores, and in particular may include a main guide bore and two secondary guide bores located to a side of the main guide bore. The main guide bore and the two secondary guide bores preferably are oriented such that the bores formed in the spine through the main guide bore and the two secondary guide bores form a first hole pattern, which when the guide is rotated 180 degre
Martin & Ferraro LLP
Robert Eduardo C.
LandOfFree
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