Track-plate carriage system

Abstract

Translational bone fixation assemblies, kits containing such assemblies, and methods of use are described herein. The described assemblies may be used in spinal fusion procedures in which a damaged or diseased disc (or part of a disc) is removed from between a pair of vertebrae and a spinal fusion spacer is placed between the vertebrae. The assemblies may be applied to an anterior portion of the affected vertebrae to span the affected disc space, and may be fixed to the vertebrae using bone screws. The assemblies may function to maintain the vertebrae aligned during the initial period following fixation in which fusion of the spacer to the adjacent vertebrae occurs. The assemblies may also function to share some of the axial spinal load applied to the fusion spacer to prevent extreme subsidence of the spacer into the vertebral body, such as where the patient has poor bone quality. The assemblies may also act to prevent the spacer from being expelled from the disc space during the initial post-operative period. Finally, these assemblies may be used in other parts of the body where the advantages of the assemblies are desired or applicable.

1 . A bone fixation assembly comprising: 
 a first plate having a first end, a second end, a longitudinal axis, and upper surface, and a lower surface, the first plate having at least two fixation holes extending from the upper surface to the lower surface, the first plate further comprising first and second extending segments extending near the first end of the first plate in the direction of the longitudinal axis, the first extending segment associated with the upper surface and the second extending segment associated with the lower surface, and a first cavity formed between the extending segments; and    at least one carriage block having at least two fixation holes;    wherein the at least one carriage block is received and retained within the first cavity and is slidably moveable with respect to the first plate.    
     
     
         2 . The assembly of  claim 1 , wherein the first plate further comprises a second cavity.  
     
     
         3 . The assembly of  claim 2 , further comprising a second carriage block slidably associated with the first plate within the second cavity.  
     
     
         4 . The assembly of  claim 3 , wherein the second carriage block is slidable independent of the first carriage block.  
     
     
         5 . The assembly of  claim 4 , wherein the second carriage block comprises at least two fixation holes.  
     
     
         6 . The assembly of  claim 2 , wherein the first and second carriage blocks are permitted to slide simultaneously.  
     
     
         7 . The assembly of  claim 2 , wherein the first carriage block is permitted to slide over a greater distance than that of the second carriage block.  
     
     
         8 . The assembly of  claim 7 , wherein the sliding distance of the second carriage block is limited by a motion-limiting element.  
     
     
         9 . The assembly of  claim 1 , wherein the first carriage block is permitted to slide from about 0 mm to about 10 mm relative to the first plate.  
     
     
         10 . The assembly of  claim 1 , wherein the first plate further comprises at least one recess.  
     
     
         11 . The assembly of  claim 10 , further comprising a securing element insertable in a recess.  
     
     
         12 . The assembly of  claim 11 , wherein the securing element is able to limit the translatable movement of the first carriage block along the longitudinal axis.  
     
     
         13 . The assembly of  claim 10 , wherein at least one recess extends from the upper surface to the lower surface.  
     
     
         14 . The assembly of  claim 10 , wherein at least one recess is substantially circular.  
     
     
         15 . The assembly of  claim 10 , wherein at least one recess is substantially oblong.  
     
     
         16 . The assembly of  claim 10 , wherein at least one recess is substantially polygonal.  
     
     
         17 . The assembly of  claim 10 , wherein at least one recess is able to receive a drill guide.  
     
     
         18 . The assembly of  claim 10 , wherein at least one recess is able to receive a temporary attachment element.  
     
     
         19 . The assembly of  claim 1 , wherein the first plate has four fixation holes, and wherein the fixation holes are arranged in pairs.  
     
     
         20 . The assembly of  claim 1 , wherein the first plate further comprises at least one indent able to facilitate the bending of the first plate.  
     
     
         21 . The assembly of  claim 1 , wherein at least two fixation holes are substantially circular.  
     
     
         22 . The assembly of  claim 21 , wherein the at least two fixation holes further comprise a clip.  
     
     
         23 . The assembly of  claim 1 , wherein at least two fixation holes are substantially oblong.  
     
     
         24 . The assembly of  claim 23 , wherein the at least two fixation holes further comprise a clip.  
     
     
         25 . The assembly of  claim 23 , wherein the at least two fixation holes each have a longitudinal axis, and wherein the at least two fixation holes allow for the translation of a fastener along the longitudinal axis of each of the at least two fixation holes.  
     
     
         26 . The assembly of  claim 23 , wherein the at least two fixation holes allow for selective placement of a fastener within each of the at least two fixation holes.  
     
     
         27 . The assembly of  claim 1 , wherein the first plate further comprises at least one internal fixation element slidably associated with the first plate.  
     
     
         28 . The assembly of  claim 27 , wherein at least one internal fixation element further comprises at least one fixation hole.  
     
     
         29 . The assembly of  claim 27 , wherein at least one internal fixation element is slidably translatable in relation to the fixation holes of the first plate.  
     
     
         30 . The assembly of  claim 27 , wherein at least one internal fixation element is slidably translatable in relation to the fixation holes of the first carriage block.  
     
     
         31 . The assembly of  claim 27 , wherein the first plate further comprises a groove, and wherein at least one internal fixation element is able to situated in the groove.  
     
     
         32 . The assembly of  claim 1 , wherein the first carriage block experiences a frictional force of at least 50 grams when slidably moving in relation to the first plate.  
     
     
         33 . The assembly of  claim 1 , wherein the first and second extending segments each have a longitudinal axis, and wherein the longitudinal axes of the first and second extending segments are divergent.  
     
     
         34 . The assembly of  claim 1 , wherein the first and second extending segments each have a longitudinal axis, and wherein the longitudinal axes of the first and second extending segments are convergent.  
     
     
         35 . The assembly of  claim 1 , wherein the first and second extending segments each have a longitudinal axis, and wherein the longitudinal axes of the first and second extending segments are substantially parallel.  
     
     
         36 . The assembly of  claim 1 , wherein the first plate comprises a length, and wherein the length of the first plate is from about 10 mm to about 140 mm.  
     
     
         37 . The assembly of  claim 1 , wherein the first carriage block comprises a length, and wherein the length of the first carriage block is from about 5 mm to about 20 mm.  
     
     
         38 . A translational bone fixation assembly comprising: 
 a first plate having a plurality of fixation holes and a longitudinal axis; and    at least a first carriage block having a plurality of fixation holes, at least a portion of the first carriage block slidably associated with at least a portion of the first plate;    wherein the first carriage block is translatable in the direction of the longitudinal axis    when the assembly is attached to at least one bone segment.    
     
     
         39 . The assembly of  claim 38 , further comprising a second carriage block slidably associated with at least a portion of the first plate.  
     
     
         40 . The assembly of  claim 39 , wherein the second carriage block is slidable independent of the first carriage block.  
     
     
         41 . The assembly of  claim 40 , wherein the second carriage block comprises a plurality of fixation holes.  
     
     
         42 . The assembly of  claim 39 , wherein the first and second carriage blocks are permitted to slide simultaneously.  
     
     
         43 . The assembly of  claim 39 , wherein the first carriage block has a range of motion greater than that of the second carriage block.  
     
     
         44 . The assembly of  claim 43 , wherein the range of motion of the second carriage block is limited by a motion-limiting element.  
     
     
         45 . The assembly of  claim 38 , wherein the first carriage block is permitted to slide from about 0 mm to about 10 mm relative to the first plate.  
     
     
         46 . The assembly of  claim 38 , wherein the first plate further comprises at least one recess.  
     
     
         47 . The assembly of  claim 46 , further comprising a securing element insertable in a recess.  
     
     
         48 . The assembly of  claim 47 , wherein the securing element is able to limit the translatable movement of the first carriage block along the longitudinal axis.  
     
     
         49 . The assembly of  claim 46 , wherein at least one recess is substantially circular.  
     
     
         50 . The assembly of  claim 46 , wherein at least one recess is substantially oblong.  
     
     
         51 . The assembly of  claim 46 , wherein at least one recess is substantially polygonal.  
     
     
         52 . The assembly of  claim 46 , wherein at least one recess is able to receive a drill guide.  
     
     
         53 . The assembly of  claim 46 , wherein at least one recess is able to receive a temporary attachment element.  
     
     
         54 . The assembly of  claim 38 , wherein the first plate has four fixation holes, and wherein the fixation holes are arranged in pairs.  
     
     
         55 . The assembly of  claim 38 , wherein the first plate further comprises at least one indent able to facilitate the bending of the first plate.  
     
     
         56 . The assembly of  claim 38 , wherein at least two fixation holes are substantially circular.  
     
     
         57 . The assembly of  claim 56 , wherein the at least two fixation holes further comprise a clip.  
     
     
         58 . The assembly of  claim 38 , wherein at least two fixation holes are substantially oblong.  
     
     
         59 . The assembly of  claim 58 , wherein the at least two fixation holes further comprise a clip.  
     
     
         60 . The assembly of  claim 58 , wherein the at least two fixation holes each have a longitudinal axis, and wherein the at least two fixation holes allow for the translation of a fastener along the longitudinal axis of each of the at least two fixation holes.  
     
     
         61 . The assembly of  claim 58 , wherein the at least two fixation holes allow for selective placement of a fastener within each of the at least two fixation holes.  
     
     
         62 . The assembly of  claim 38 , wherein the first plate further comprises at least one internal fixation element slidably associated with the first plate.  
     
     
         63 . The assembly of  claim 62 , wherein at least one internal fixation element further comprises at least one fixation hole.  
     
     
         64 . The assembly of  claim 62 , wherein at least one internal fixation element is slidably translatable in relation to the fixation holes of the first plate.  
     
     
         65 . The assembly of  claim 62 , wherein at least one internal fixation element is slidably translatable in relation to the fixation holes of the first carriage block.  
     
     
         66 . The assembly of  claim 62 , wherein the first plate further comprises a groove, and wherein at least one internal fixation element is able to situated in the groove.  
     
     
         67 . The assembly of  claim 38 , wherein the first carriage block experiences a frictional force of at least 50 grams when slidably moving in relation to the first plate.  
     
     
         68 . The assembly of  claim 38 , wherein the first plate further comprises a bore, and wherein an extension element extends through the bore.  
     
     
         69 . The assembly of  claim 68 , wherein the extension element is able to stop the sliding movement of the first carriage block.  
     
     
         70 . The assembly of  claim 68 , wherein the extension element is permanently attached to the first plate.  
     
     
         71 . The assembly of  claim 38 , wherein the first plate comprises a length, and wherein the length of the first plate is from about 10 mm to about 140 mm.  
     
     
         72 . The assembly of  claim 38 , wherein the first carriage block comprises a length, and wherein the length of the first carriage block is from about 5 mm to about 20 mm.  
     
     
         73 . The assembly of  claim 38 , wherein the portion of the first plate slidably associated with the first carriage block is a dovetail portion.  
     
     
         74 . The assembly of  claim 73 , wherein at least a portion of the dovetail portion is capable of being deformed to limit the translational movement of the first carriage block in at least one direction.  
     
     
         75 . A translational bone fixation assembly comprising: 
 a first plate having a plurality of fixation holes and a longitudinal axis; and    at least a first carriage block having a plurality of fixation holes, at least a portion of the first carriage block slidably associated with at least a portion of the first plate;    wherein the first carriage block is translatable in the direction of the longitudinal axis    under a coaxial force of at least about 50 grams.    
     
     
         76 . The assembly of  claim 75 , further comprising a second carriage block slidably associated with at least a portion of the first plate.  
     
     
         77 . The assembly of  claim 76 , wherein the second carriage block is slidable independent of the first carriage block.  
     
     
         78 . The assembly of  claim 77 , wherein the second carriage block comprises a plurality of fixation holes.  
     
     
         79 . The assembly of  claim 76 , wherein the first and second carriage blocks are permitted to slide simultaneously.  
     
     
         80 . The assembly of  claim 76 , wherein the first carriage block has a range of motion greater than that of the second carriage block.  
     
     
         81 . The assembly of  claim 80 , wherein the range of motion of the second carriage block is limited by a motion-limiting element.  
     
     
         82 . The assembly of  claim 75 , wherein the first carriage block is permitted to slide from about 0 mm to about 4 mm relative to the first plate.  
     
     
         83 . The assembly of  claim 75 , wherein the first plate further comprises at least one recess.  
     
     
         84 . The assembly of  claim 83 , further comprising a securing element insertable in a recess.  
     
     
         85 . The assembly of  claim 84 , wherein the securing element is able to limit the translatable movement of the first carriage block along the longitudinal axis.  
     
     
         86 . The assembly of  claim 83 , wherein at least one recess is substantially circular.  
     
     
         87 . The assembly of  claim 83 , wherein at least one recess is substantially oblong.  
     
     
         88 . The assembly of  claim 83 , wherein at least one recess is substantially polygonal.  
     
     
         89 . The assembly of  claim 83 , wherein at least one recess is able to receive a drill guide.  
     
     
         90 . The assembly of  claim 83 , wherein at least one recess is able to receive a temporary attachment element.  
     
     
         91 . The assembly of  claim 75 , wherein the first plate has four fixation holes, and wherein the fixation holes are arranged in pairs.  
     
     
         92 . The assembly of  claim 75 , wherein the first plate further comprises at least one indent able to facilitate the bending of the first plate.  
     
     
         93 . The assembly of  claim 75 , wherein at least two fixation holes are substantially circular.  
     
     
         94 . The assembly of  claim 93 , wherein the at least two fixation holes further comprise a clip.  
     
     
         95 . The assembly of  claim 75 , wherein at least two fixation holes are substantially oblong.  
     
     
         96 . The assembly of  claim 95 , wherein the at least two fixation holes further comprise a clip.  
     
     
         97 . The assembly of  claim 95 , wherein the at least two fixation holes each have a longitudinal axis, and wherein the at least two fixation holes allow for the translation of a fastener along the longitudinal axis of each of the at least two fixation holes.  
     
     
         98 . The assembly of  claim 95 , wherein the at least two fixation holes allow for selective placement of a fastener within each of the at least two fixation holes.  
     
     
         99 . The assembly of  claim 75 , wherein the first plate further comprises at least one internal fixation element slidably associated with the first plate.  
     
     
         100 . The assembly of  claim 99 , wherein at least one internal fixation element further comprises at least one fixation hole.  
     
     
         101 . The assembly of  claim 99 , wherein at least one internal fixation element is slidably translatable in relation to the fixation holes of the first plate.  
     
     
         102 . The assembly of  claim 99 , wherein at least one internal fixation element is slidably translatable in relation to the fixation holes of the first carriage block.  
     
     
         103 . The assembly of  claim 99 , wherein the first plate further comprises a groove, and wherein at least one internal fixation element is able to situated in the groove.  
     
     
         104 . The assembly of  claim 75 , wherein the first carriage block experiences a frictional force of at least 50 grams when slidably moving in relation to the first plate.  
     
     
         105 . The assembly of  claim 75 , wherein the first plate further comprises a bore, and wherein an extension element extends through the bore.  
     
     
         106 . The assembly of  claim 105 , wherein the extension element is able to stop the sliding movement of the first carriage block.  
     
     
         107 . The assembly of  claim 105 , wherein the extension element is permanently attached to the first plate.  
     
     
         108 . The assembly of  claim 75 , wherein the first plate comprises a length, and wherein the length of the first plate is from about 10 mm to about 140 mm.  
     
     
         109 . The assembly of  claim 75 , wherein the first carriage block comprises a length, and wherein the length of the first carriage block is from about 5 mm to about 20 mm.  
     
     
         110 . The assembly of  claim 75 , wherein the portion of the first plate slidably associated with the first carriage block is a dovetail portion.  
     
     
         111 . The assembly of  claim 110 , wherein at least a portion of the dovetail portion is capable of being deformed to limit the translational movement of the first carriage block in at least one direction.  
     
     
         112 . A method of securing at least two bone elements comprising the steps of: 
 (a) providing a translatable bone fixation assembly having a first plate having a plurality of fixation holes and a longitudinal axis, and a first carriage block having a plurality of fixation holes, wherein the carriage block is slidably associated with the first plate;    (b) inserting at least one fastener through at least one fixation hole in the first plate and into a first bone element;    (c) inserting at least one fastener through at least one fixation hole in the first carriage block and into a second bone element; and    (d) permitting the carriage block to slide in the direction of the longitudinal axis after implantation of the bone fixation assembly.    
     
     
         113 . The method of  claim 112 , wherein the assembly further comprises a second carriage block slidably associated with the first plate, and wherein the second carriage block has a plurality of fixation holes.  
     
     
         114 . The method of  claim 113 , further comprising the step, inserted before step (d), of inserting at least one fastener through at least one fixation hole in the second carriage block and into a third bone element.  
     
     
         115 . The method of  claim 114 , wherein the third and second bone elements are separated by the first bone element.  
     
     
         116 . The method of  claim 112 , further comprising the step of inserting applying a motion-limiting element to limit the motion of the first carriage block.  
     
     
         117 . The method of  claim 112 , further comprising the step, inserted before step (b), of drilling at least one hole in at least one bone element in a location of desired fastener insertion.  
     
     
         118 . The method of  claim 112 , wherein the first and second bone elements are adjacent vertebrae.  
     
     
         119 . The method of  claim 118 , further comprising the step of inserting an intervertebral spacer between the first and second bone elements.  
     
     
         120 . A kit for use with bone fixation procedures comprising: 
 at least a first plate having a plurality of fixation holes and a longitudinal axis;    at least a first carriage block having a plurality of fixation holes, at least a portion of the first carriage block slidably associated with at least a portion of a first plate;    wherein the first carriage block is translatable in the direction of the longitudinal axis    when the assembly is attached to at least one bone segment.    
     
     
         121 . The kit of  claim 120 , further comprising at a first fastener for use with at least one fixation hole.  
     
     
         122 . The kit of  claim 121 , further comprising a second fastener for use with at least one fixation hole, wherein the first fastener is substantially different than the second fastener.  
     
     
         123 . The kit of  claim 120 , further comprising a second plate and a second carriage block.  
     
     
         124 . The kit of  claim 123 , wherein the first carriage block is slidably associated with the second plate.  
     
     
         125 . The kit of  claim 123 , wherein the second carriage block is slidably associated with the first plate.  
     
     
         126 . The kit of  claim 123 , wherein the first and second carriage blocks are able to be simultaneously slidably associated with the first plate.  
     
     
         127 . The kit of  claim 120 , further comprising at least one motion-limiting element for use with a carriage block.  
     
     
         128 . The kit of  claim 120 , further comprising at least one temporary attachment element.  
     
     
         129 . The kit of  claim 120 , further comprising at least one drill guide.  
     
     
         130 . The kit of  claim 120 , further comprising at least one drill.