BACKGROUND OF THE INVENTION

The present invention relates to apparatuses and methods for use in performing spinal surgery and, in particular, to tools and methods of using such tools, especially for percutaneously implanting spinal screws and for implanting a rod for spinal support and alignment, using minimally invasive techniques.

For many years, spinal osteosynthesis apparatuses have been utilized to correct spinal deformities, injuries or disease. In such procedures, elongate rods are surgically attached to vertebrae of the spine to provide support and/or to realign or reposition certain vertebrae. Such rods are secured to vertebrae utilizing bone screws and other spinal implants. In order to reduce the impact of such surgery on the patient, a desirable approach is to insert such implants percutaneously or with surgical techniques that are minimally invasive to the body of the patient.

Problems arise when implantation tools designed for traditional surgery that is highly invasive are utilized in percutaneous surgery. The tools may be bulky, oversized or have irregular surfaces or protrusions. A projecting actuator arm or fastening member may be useful with respect to the spinal screw implantation process or the rod reduction process, but there is insufficient clearance to use such structure and/or such structure may produce additional invasive trauma which the percutaneous surgery is attempting to avoid.

A percutaneous procedure also presents a problem with implantation of rods that are elongate and have historically required a long incision and open wound in order to provide for the length of the rod and the space required for the surgeon's hands to manipulate the rod. Such problems are then compounded by the implants and insertion tools used with the rod.

Consequently, it is desirable to develop apparatuses and techniques that allow for the insertion of bone screws, the insertion and reduction of a rod into the bone screws and the securing of the rod to the bone screws with significantly less invasion into the body of the patient and with minimal surgical incision of the skin over the operational site.

SUMMARY OF THE INVENTION

A tool set according to the invention is provided for percutaneously implanting bone screws and an associated spinal rod in a patient. The tool assembly includes first and second end guide tools, each guide tool having an elongate body, an outer surface and a channel with a lateral opening extending through the outer surface and along a longitudinal axis an entire length of the guide tool. The channel and channel opening are sized and shaped for side loading and receiving of an end of the rod and also for receiving spinal implant fasteners and cooperating manipulation tools.

Near a bottom of the end guide tool body is a rigid, rod holding structure disposed opposite the lateral opening. The rigid rod holding structure projects laterally outwardly from the elongate body outer surface, and is sized and shaped to closely receive and abut against an end of the rod. The rod holding structure holds the rod end at a location outside of the spinal implant. The structure preferably includes a pair of spaced arms extending laterally about the end guide tool body. The guide tool body defines an opening disposed adjacent the arms, with the opening sized and shaped to receive the rod therethrough.

A tool set according to the invention may also include one or more intermediate guide tools, each having first and second elongate legs defining an elongate through-slot sized and shaped for receiving a rod therethrough.

Both the end guide tools and the intermediate guide tool have opposed spinal implant engaging structure disposed near a bottom thereof. The implant engaging structure of the illustrated embodiment includes first and second opposed radially inwardly projecting pins. The pins are sized and shaped to be received in cooperating apertures in the spinal implant for releaseable attachment thereto. Preferably each pin has an upwardly projecting lip sized and shaped to be received in an upwardly projecting inner recess of the spinal implant aperture, allowing for a snap-on, snap-off cooperation between the guide tool and the spinal implant.

To provide such a snap-on, snap-off cooperation between the end guide tool and a spinal implant, each end guide tool includes a narrow slot disposed opposite the lateral opening. The narrow slot and lateral opening cooperate to allow manual flexing of the guide tool body to increase a distance between the first and second pins during insertion and removal of the guide tool on the spinal implant.

A tool set of the invention further includes a driving tool attachable to both the end and intermediate guide tools. The driving tool is receivable in the tools and operably attachable to the spinal implant for rotating and driving the implant into bone. In an embodiment according to the invention, the end and intermediate guide tools have outer guide and advancement structure, such as a thread at an upper portion of the tool body. The driving tool has a fastener, a stem and a driving structure disposed at a lower end of the stem, the driving structure for rotating and driving the implant into bone. The fastener is freely rotatable with respect to the stem and includes an inner guide and advancement structure that is rotatingly mateable with the outer guide and advancement structure of the guide tools.

The tool set further includes a rod pusher attachable to both the end and intermediate guide tools. The rod pusher includes a sleeve and a driving end. The sleeve is receivable over the elongate guide tool body and operably attachable to the body for rotating thereabout, with the rotational movement of the sleeve also translating the driving end along the body. The rod pusher includes an inner guide and advancement structure mateable with the outer guide and advancement structure of the respective guide tool.

The tool set may also include an elongate torquing tool having a handle and a stem receivable in the channel of both the end and intermediate guide tools and attachable to an implant fastener. Cooperating with the torquing tool is an elongate anti-torque tool having a handle and a sleeve receivable over the respective guide tool body. The sleeve is sized and shaped to seat upon and abut against a rod at either side of the guide tool body, resisting any rotational movement of the anti-torque tool relative to the end guide tool.

A vertebral support rod implantation kit according to the invention, adapted for use with a plurality of vertebrae, includes a plurality of polyaxial bone screws, each bone screw being adapted for implantation in one vertebra, each of the bone screws having an attachment structure. The kit also includes an elongate rod having first and second ends, the rod sized and shaped to extend between a pair of end bone screws of the plurality of bone screws. The kit further includes a plurality of closure tops with each closure top being sized and shaped to mate with a respective bone screw and capture or retain the elongate rod within a cavity or channel defined by the respective arms of the bone screw. Additionally, the kit includes a pair of end guide tools, and may include one or more intermediate guide tools, each guide tool being attachable to the driver and the rod pusher previously described herein.

In a method according to the invention, a spinal fixation tool assembly is assembled by first attaching a bone screw head of a spinal implant screw to a mating attachment structure disposed at a first end of an elongate guide tool implant engaging member, the guide tool defining a laterally opening channel and having a second attachment structure disposed at a second end thereof. A driver is then inserted in the guide tool and attached spinal implant screw. The driver includes a fastener that is rotated in a first direction to mate the driver with the second attachment structure on the guide tool and thereby engage the driver with the spinal implant screw.

A method according to the invention includes the steps of inserting the attached driver, guide tool and spinal implant screw into an incision, especially a minimally invasive incision sized to snugly or closely receive the assembled tools and bone screw, and into contact with a vertebra, followed by turning the driver handle. By turning the handle, only the driver and the screw are rotated, driving the spinal implant screw into the vertebra.

Further method steps according to the invention include detaching the driver from the guide tool and attaching a rod pusher onto the guide tool by placing the rod pusher sleeve onto the guide tool and rotating the sleeve. The rod is then guided into and through all the guide tool channels. The sleeve is rotated, advancing a rod pushing end toward the bone screw and pushing the rod toward the screw until the ends of the rod are in contact with the laterally extending, rigid rod holding structure disposed near the bottom of the end guide tools. The method further includes the step of fixing closure tops to the spinal implant screw heads, with the rod being captured between the spinal implant screw and the closure top.

Objects and Advantages of the Invention

Therefore, objects of the present invention are: to provide a compact tool assembly for supporting and installing bone screws and other implants with minimal surgical invasion to the patient; to further provide a set of tools for implanting a spinal rod for support or alignment along a human spine with minimal surgical invasion of the patient; to provide such a set of tools including a pair of end tool guides for slidably guiding opposed ends of the rod toward end bone screws attached to the end guide tools; to provide such a set of tools including intermediate guide tools for each intermediate bone screw that guide the rod in slots therethrough to respective bone screws; to provide such a set of tools including rod and implant fastener or closure top installation tools for assisting in securing the rod in the bone screws; to provide such a set of tools wherein the guide tools are easily attached to and disengaged from the bone screws; to provide such a set of tools wherein the guide tools, guide tool supports or stabilizers, deployment tools, rod reduction tools, bone screw installation tools and implant fastener installation tools are all easily aligned, positioned, and engaged, if necessary, with respect to the bone screw and are disengaged from the bone screw and other tools in the installation assembly by manual manipulation of the surgeon outside the patient's skin; to provide a method of implanting a rod into bone screws within a patient with minimal surgical invasion of the patient; to provide such a method utilizing the previously described tools for percutaneous implantation of such a rod; and to provide such a set of tools and methods that are easy to use and especially adapted for the intended use thereof and wherein the tools are comparatively inexpensive to produce.

Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention.

The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.

