Spinal disc space distractor

Abstract

A distractor for separating adjacent elements, such as vertebrae. The distractor preferably has a scissors-type distracting mechanism, either in a simple scissors or double-acting scissors configuration. A set of blades is provided on each jaw such that an implant may be inserted between the spaced apart blades. The set of blades includes at least two blades.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of copending U.S. patent application Ser. No. 09 / 879,911, filed Jun. 14, 2001, which is a continuation of U.S. patent application Ser. No. 09 / 411,161, filed Oct. 1, 1999, now U.S. Pat. No. 6,261,296, which claims priority to U.S. Provisional Application No. 60 / 102,669, filed Oct. 2, 1998, which are incorporated by reference herein in their entirety.FIELD OF THE INVENTION [0002] The present invention relates to a device and method for spreading apart adjacent vertebrae of a vertebral column so that an implant may be inserted therebetween. More particularly, the present invention relates to a distractor device shaped and configured for minimally invasive insertion and use, such as for distraction of vertebrae using an anterior or anterolateral approach. BACKGROUND OF THE INVENTION [0003] Back pain can be caused by either one or a combination of the following: a loss of disc height, compression of nerve ro...

AI Technical Summary

Benefits of technology

[0006] In accordance with the principles of the present invention, a spinal disc distractor is provided to allow for an implant insertion technique to be performed during distraction of the disc space. The implants are slid into the disc space between the distractor blades, preferably while the blades are in contact with the upper and lower surfaces of the adjacent vertebral bodies. The distractor of the present invention is formed to be as minimally invasive and atraumatic as possible such that it may readily be used in an anterior or anterolaterial approach. Thus, the distractor of the present invention is configured to be used in the confined spaces of the human anatomy through a small surgical incision and permits the use of laparoscopic approaches like Balloon Assisted Endoscopic Retroperitoneal Gasless (“BERG”).

[0007] In a preferred embodiment, the distractor of the present invention has a scissor-like configuration with a pair of handles pivotally connected together. A distractor jaw is coupled to a distal end of each handle such that movement of the handles together draws the jaws apart to separate the vertebrae being treated. In an even more preferred embodiment, the jaws and handles are pivotally coupled together in a double-acting scissor-like configuration to further reduce the space required to move the jaws apart and thus further minimize the invasiveness of the device and procedure.

[0008] Although the handles, jaws, and distractor mechanism of the present invention may all lie in the same plane, in order to facilitate visualization of the treatment site during distraction and insertion of an implant, at least the handles may be angled away from the plane of the distractor jaws. In a preferred embodiment, the distractor mechanism is angled downwardly with respect to the jaws and the handles are angled downwardly with respect to the distractor mechanism to further enhance visualization and also to permit greater space for the implant holder adjacent the proximal end of the distractor during insertion of the implant.

[0010] The blades of the distractor of the present invention are configured to increase versatility of the distractor. In a first embodiment of the present invention, the blades are removably coupled to the distractor jaws. Thus, the blades may be changed, as necessary or desired, for a given procedure or patient.

[0011] In another embodiment, the blades of the distractor are gradually curved to be out of the plane of the distractor mechanism. Because of the gradual curve, the distal end of the jaws may safely be manipulated through the patient's body with as minimal contact as possible with organs and vasculature including major blood vessels such as the vena cava and aorta. Moreover, such curvature permits insertion through a smaller incision because of the increased manipulability of the gradually curved blades through small openings and spaces.

[0013] The spinal disc distractor of the present invention is thus designed to distract disc space atraumatically with respect to both the vertebrae and the implant during endplate preparation, implant sizing, and implant insertion. The distractor may be used in a straight anterior, anterolateral, or lateral approach, and may be used in either an open or a laparoscopic procedure. Moreover, the distractor is designed to ensure the selection of an anatomically correct implant size by permitting the annulus to be fully stretched so that the largest possible implant may be inserted and compressed upon release of the vertebrae, thereby enhancing stability and assuring correct placement of the implant. Thus, the present invention permits disc height and lordosis to be restored. The jaws are shaped and configured to preserve the endplate and the vertebral body during distraction, as well as to permit insertion of an implant during distraction. The risk of breakage of allograft implants and other cages made from brittle materials during insertion is thereby reduced.

Problems solved by technology

However, the technique for the insertion of these implants generally does not achieve distraction because of their height limitations, thus making it difficult to restore the natural disc height.

The force necessary to insert these implants (such as by drilling and tapping) may cause damage to the vertebrae or vertebral endplates at the insertion site.

Moreover, allograft products and cages made out of other brittle materials (e.g., carbon fiber and ceramics) may break during insertion, particularly when distraction is not used and external force is necessary to insert the implant.

Threaded cages on the other hand do not restore lordosis, and do not allow for atraumatic distraction to restore disc height.

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