Lateral plate and spinal implant system and method

Abstract

A lateral plate assembly has an elongated lateral plate for attachment to adjacent vertebrae having a first end portion and a second end portion and a pair of apertures for receiving a first and a second bone screw. The pair of apertures includes a first aperture which is an opening positioned in the first end portion for receiving the first bone screw and a second aperture which is a slotted opening to receive the second bone screw. The second end portion of the lateral plate has an open end with channelled internal sides for receiving and holding a moveable washer on top of the slotted opening. The washer is configured to move along a length of the slotted aperture. The moveable washer has an opening for holding a head of the second bone screw. Movement of the washer relative to the slotted opening increases or decreases the distance between locations of the respective screw heads.

What is claimed is: 
     
         1 . A lateral plate assembly comprising:
 an elongated lateral plate for attachment to adjacent vertebrae having a first end portion and a second end portion and a pair of apertures for receiving a first and a second bone screw, the pair of apertures being a first aperture having an opening positioned in the first end portion for receiving the first bone screw and a second aperture having a slotted opening to receive the second bone screw; and   wherein the second end portion of the lateral plate has an open end with channelled internal sides for receiving and holding a moveable washer on top of the slotted opening and configured to move along a length of the slotted aperture, the moveable washer having an opening for holding a head of the second bone screw, movement of the washer relative to the slotted opening increases or decreases the distance between locations of the respective screw heads.   
     
     
         2 . The lateral plate assembly of  claim 1  further comprises:
 a threaded third aperture on the lateral plate interposed between the first and second aperture; 
 an anti-back out mechanism assembly having a locking tab with an externally threaded screw and a locking ring, wherein the threaded screw is locked to an aperture of the locking tab and the external thread of the screw engages the threaded third aperture of the lateral plate and wherein the two bone screws when fastened to the vertebrae are prevented from back out by the anti-back out mechanism as the locking tab projects over at least portions of heads of each bone screw; and 
 an attachment fastener for fixing the elongated plate to the implant body, the attachment fastener extends through a central opening of the externally threaded screw to fix the implant body to the lateral plate. 
 
     
     
         3 . The lateral plate assembly of  claim 1  wherein the elongated lateral plate has a low profile thickness. 
     
     
         4 . The lateral plate assembly of  claim 3  wherein the thickness of the lateral plate is in the range of 3 mm to 5 mm. 
     
     
         5 . The lateral plate assembly of  claim 4  wherein the lateral plate thickness is 4 mm. 
     
     
         6 . The lateral plate assembly of  claim 1  wherein the lateral plate has a maximum width at the second end of 20 mm or less. 
     
     
         7 . The lateral plate assembly of  claim 6  wherein the maximum width is 15 mm. 
     
     
         8 . The lateral plate assembly of  claim 7  wherein the anti-back out mechanism assembly lies in the recess and extends over at least partially the first opening and second slotted opening. 
     
     
         9 . The lateral plate assembly of  claim 8  wherein the anti-back out mechanism assembly has an outer surface that is flush or below relative to an outer surface of the lateral plate when tightened into the recess. 
     
     
         10 . The lateral plate assembly of  claim 1  wherein the bone screws each have polyaxial heads adapted to be flush or below the lateral plate when in the respective first opening or the washer opening when tilted on an angle in the range of −2 degrees or toward interior center of the lateral plate or +5 degrees toward the ends of the lateral plate yielding a total screw angulation of −4 degrees to 10 degrees between the screws when the screw heads are flush. 
     
     
         11 . The lateral plate assembly of  claim 1  wherein the first and second screw can have an angulation of −2 degrees to +15 degrees each yielding a maximum angulation between screws of 30 degrees. 
     
     
         12 . A spinal implant assembly comprises:
 an implant body for insertion between adjacent vertebral bodies, the body having an upper load supporting surface and a lower load supporting surface spaced by walls, the walls including a pair of opposing sidewalls and a proximal end wall and a distal end wall, the proximal end wall having a threaded aperture;   an elongated lateral plate having a first end portion and a second end portion and a pair of apertures for receiving a first and a second bone screw, a first aperture having an opening positioned in the first end portion for receiving and holding the first bone screw and a second aperture having a slotted opening to receive the second bone screw, wherein the apertures for receiving first and second bone screws are positioned spaced from an interposed threaded third aperture for alignment with the thread aperture of the fusion implant body; and   an attachment fastener for fixing the elongated lateral plate to the implant body at the threaded apertures.   
     
     
         13 . The spinal implant assembly of  claim 12  further comprises:
 an anti-back out mechanism assembly having a locking tab with an externally threaded screw and a locking ring, wherein the threaded screw is locked externally threaded to the aperture of the locking tab and the external thread engages the threaded third aperture of the lateral plate and wherein the two bone screws when fastened to the vertebrae are prevented from back out by the anti-back out mechanism as the locking tab projects over at least portions of heads of each bone screw, and the attachment fastener extends through the washer to fix the elongated lateral plate and implant body. 
 
     
     
         14 . The spinal implant assembly of  claim 13  wherein the second end portion of the lateral plate has an open end with channelled internal sides for receiving and holding a moveable washer on top of the slotted opening and configured to move along a length of the slotted opening, the moveable washer having an opening for holding a head of the second bone screw, movement of the washer relative to the slotted opening increases or decreases the distance between locations of the respective screw heads. 
     
     
         15 . The lateral plate assembly of  claim 12  wherein the elongated lateral plate has a low profile thickness. 
     
     
         16 . The lateral plate assembly of  claim 15  wherein the thickness of the lateral plate is in the range of 3 mm to 5 mm. 
     
     
         17 . The lateral plate assembly of  claim 16  wherein the lateral plate thickness is 4 mm. 
     
     
         18 . The lateral plate assembly of  claim 12  wherein the lateral plate has a maximum width at the second end of 20 mm or less. 
     
     
         19 . The lateral plate assembly of  claim 18  wherein the maximum width is 15 mm. 
     
     
         20 . The lateral plate assembly of  claim 19  wherein the anti-back out mechanism assembly lies in the recess and extends over at least partially the first opening and second slotted opening. 
     
     
         21 . The lateral plate assembly of  claim 20  wherein the anti-back out mechanism assembly has an outer surface that is flush or below relative to an outer surface of the lateral plate when tightened into the recess. 
     
     
         22 . The lateral plate assembly of  claim 12  wherein the bone screws each have polyaxial heads adapted to be flush or below the lateral plate when in the respective first opening or the washer opening when tilted on an angle in the range of −2 degrees or toward interior center of the lateral plate or +5 degrees toward the ends of the lateral plate yielding a total screw angulation of −4 degrees to 10 degrees between the screws when the screw heads are flush. 
     
     
         23 . The lateral plate assembly of  claim 12  wherein the first and second screw can have an angulation of −2 degrees to +15 degrees each yielding a maximum angulation between screws of 30 degrees.