Apparatus and method for anterior intervertebral spinal fixation and fusion

Abstract

A method of using a plurality of blades within a fixation device to attach to a vertebra is provided. Each blade includes a body having a central opening configured to rotate on a shaft within a housing of the fixation device, control openings on opposing sides of the central opening sized to engage prongs of a rotating tool, and at least one cutting extension with a sharp leading edge extending from the body in an orientation about an axis of the shaft, wherein upon rotation of the blade by the rotating tool about the shaft in a direction in which the at least one cutting extension is oriented, the at least one cutting extension will break an endplate of a vertebra and hook into the vertebra.

Claims

1. A method of using a plurality of blades within a fixation device to attach to a vertebra, the method comprising: providing a plurality of blades, each blade comprising: a body having a central opening configured to rotate on a shaft within a housing of the fixation device; control openings on opposing sides of the central opening sized to engage prongs of a rotating tool; and at least one cutting extension with a sharp leading edge extending from the body in an orientation about an axis of the shaft, the blades including at least one first blade having the at least one cutting extension in a first orientation about the axis of the shaft and at least one second blade having the at least one cutting extension in a second orientation about the axis of the shaft; inserting the blades including the at least one first blade and the at least one second blade on the shaft within the fixation device between adjacent vertebrae; rotating the blades using the rotating tool via the control openings about the shaft in a direction in which the at least one cutting extension is oriented, including clockwise rotation of the at least one first blade in the direction of the first orientation and counterclockwise rotation of the at least one second blade in the direction of the second orientation; and breaking an endplate of the vertebra with the at least one cutting extension of the blades, hooking into the vertebra, and rigidly securing the vertebra to the fixation device.

2. The method of claim 1, wherein the body of each of the blades includes a shape configured to expand a disk space between the vertebrae as the blades are rotated, wherein rotating the blades comprises expanding the disk space between the vertebrae.

3. The method of claim 1, wherein the method comprises alternating the at least one first blade and the at least one second blade between the first orientation and the second orientation when preloaded onto the shaft.

4. The method of claim 1, wherein the method comprises rotating sequentially the at least one first blade and the at least one second blade with the prongs of the rotating tool via the control openings.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 Anterior view of the lumbar spine demonstrating vertebra (1) alternating with disk (2).

(2) FIG. 2 Anterior view of the vertically sliced lumbar spine demonstrating internal composition of the vertebra with dense endplate (3) and softer inner part (4).

(3) FIG. 3 Lateral (side) view of the vertebral column demonstrating normal curvature (lordosis) of the lumbar spine.

(4) FIG. 4 Lateral (side) view of the preferred embodiment of the housing with front opening (8), back wall (9), and a central shaft (10) fixed to the back wall (9).

(5) FIG. 5 Anterior (front) view through the front opening (8) of the housing with lateral weight hearing walls (5), top (6) and bottom (7) openings, and the central shaft (10).

(6) FIG. 6 Superior (top) view through the top opening (6) of the housing, showing the central shaft (10).

(7) FIG. 7 Perspective view of the housing with lateral weight bearing walls (5), top (6) and bottom (7) openings, back wall (9), and a central shaft (10) including threaded end (21).

(8) FIG. 8 Front view of the preferred embodiment of the clockwise blade. The cuffing extensions (11) have sharp ends (22) that cut through the endplate 3 and into the cancellous bone (4) of vertebra (1). The central opening (12) fits over the shaft 10 of the housing. The control nut (13) is used to handle the blade and to thread onto the shaft (10). The body of the blade (14) provides additional central weight bearing support against vertebral endplates.

(9) FIG. 9 Front view of the preferred embodiment of the counterclockwise blade.

(10) FIG. 10 Top view of the counterclockwise blade showing cutting extension (11) having sharp end (22) and control nut 13.

(11) FIG. 11 Perspective view of the counterclockwise blade

(12) FIG. 12 Preferred embodiment of the insertion instrument for the housing. The prongs (15) fit inside the lateral walls (5) of the housing but clear the central opening (16) occupied by the blades.

(13) FIG. 13 Preferred method of housing placement into collapsed disk space (2) between vertebras (1).

(14) FIG. 14 Housing inside expanded disk space (2).

(15) FIG. 15 Preferred embodiment of a blade introducer having a receptacle (17) for the control nut (13) and a central opening (18) for the shaft (10).

(16) FIG. 16 Blade of FIG. 8 introduced horizontally into the housing of FIG. 7 using the blade introducer of FIG. 15.

(17) FIG. 17 Blade rotated vertically with cutting extensions (11) piercing vertebral endplates and hooking into vertebras (1).

(18) FIG. 18 Alternative embodiment of the blade having central opening (12) and control openings (19) on opposing sides of the central opening (12) to rotate the blade about the shaft (10). These blades are preloaded into the housing prior to placement of the housing into the disk space.

(19) FIG. 19 Transparent housing and central shaft (10) with pre-loaded blades showing front two blades rotated into final vertical position.

(20) FIG. 20 Blade rotating tool fits into control openings (19) of clockwise and counterclockwise blades with prongs (20) of the rotating tool engaging the first three blades via control openings (19).

DETAILED DESCRIPTION

(21) An implant device for reconstruction, fixation and bone fusion of bone vertebras through an anterior approach to the human spine. This implant device enables rigid fixation in all planes of motion including extension of the spine, it possesses structural characteristics necessary to reconstruct and maintain disk height, it provides space for bone grafting material and produces a plurality of perforations through endplates above and below to enhance bony fusion.

(22) The implant device consists of the outer structure or shell which is designed to conform to the disk space, provide openings for bony ingrowths and maintain the disk height by providing adequate structural strength and sufficient weight bearing surface. The shell or housing contains a shaft (10) which runs through its central axis from the back (9) to the front (8) and is fixed to the shell (FIG. 7).

(23) In the preferred embodiment the shell is impacted into the disk space (FIG. 14) using the shell introducer (FIG. 13). The shell introducer includes prongs (15) that fit inside the sides (5) of the shell but is open (16) in the center to allow for blades (FIG. 12).

(24) Once the shell is placed in a correct position between vertebras (1), individual blades (FIG. 11) are selected, mounted onto the introducer (FIG. 15) and threaded onto the shaft (10) in horizontal orientation (FIG. 16). The blade is placed as deep as it can go and then rotated into vertical orientation breaking the endplate and hooking into the vertebra (1) (FIG. 17). Blades alternate between clockwise and counterclockwise orientation. Variable size blades can be selected to better approximate configuration of the disk space.

(25) Once all the blades are engaged, a tightening nut is threaded onto the end (21) of the shaft (10) of FIG. 7.

(26) In an alternative embodiment, alternating clockwise and counterclockwise blades (FIG. 18) are pre-loaded onto the shaft (10) and inside the housing (FIG. 19). The blades include a central opening (12) and control openings (19) on opposing sides of the central opening (12) to rotate the blade about the shaft (10). With the help of a blade rotating tool with prongs (20) engaging the control openings (19) (FIG. 20), the blades are rotated sequentially going from superficial to deep.

(27) In another embodiment the housing expands horizontally and contains two shafts, which separate from each other upon expansion of the housing. In the initial collapsed configuration, preloaded clockwise and counterclockwise blades threaded on different shafts imbricate between each other. After the cage is expanded, blades are pulled apart.

(28) In another embodiment, a body (14) of a blade is configured as an oval so that the disk space is expanded as a blade is rotated.