Methods and apparatus for an osteotomy fixation or arthrodesis cage

Abstract

A method and apparatus for an osteotomy fixation or arthrodesis cage allows the adjustment of the relative position of two bone segments while supporting the joining of those bone segments into one structure through the implant and methods described herein. The implant's embodiments fixate to the adjacent bones while inter-positioning its body between the bone segments. This inter-positioning allows anatomical adjustments in the distance between and angle of the bone segments. The adjustment is further enhanced by the use of shape memory materials that when activated through the application of heat energy, transition from a second shape to a first shape while changing the distance between the bones or their relative angle. This method and apparatus can be used on any adjacent bone or bone segments including but not limited to the vertebrae of the spine or long bone such as the tibia or metatarsal.

1 . A cage, comprising:
 (a) a body adapted for insertion into a space between a first bone and a second bone, wherein:
 (i) the body comprises a first engagement plate, a second engagement plate, and a spacing member coupling the first engagement plate with the second engagement plate, 
 (ii) the space has a boundary comprising a first portion of the surface of the first bone and a first portion of the surface of the second bone, and 
 (iii) the first engagement plate is operable to face the first portion of the surface of the first bone while the second engagement plate faces the first portion of the surface of the second bone; 
   (b) a first leg secured to the body and adapted to engage the first bone at a second portion of the surface of the first bone, wherein the second portion of the surface of the first bone is exterior to the space; and   (c) a second leg secured to the body and adapted to engage the second bone at a second portion of the surface of the second bone, wherein the second portion of the surface of the second bone is exterior to the space.   
     
     
         2 . The cage according to  claim 1 , wherein the body comprises shape memory material and is operable to transition to an end use shape upon the application of energy thereto. 
     
     
         3 . The cage according to  claim 2 , wherein the body is operable to deform so as to change the relative position of a first bone and a second bone. 
     
     
         4 . The cage according to  claim 2 , wherein the first leg is operable to deform so as to move, engage and provide fixation in the first bone. 
     
     
         5 . (canceled) 
     
     
         6 . The cage according to  claim 2 , wherein the first leg is secured to the first engagement plate and the second leg is secured to the second engagement plate. 
     
     
         7 . The cage according to  claim 3 , wherein the body is operable to distract the first bone and the second bone to a desired corrective position. 
     
     
         8 . The cage according to  claim 2 , wherein, upon the body, the first engagement plate and the second engagement plate are operable to contract toward each other. 
     
     
         9 . The cage according to  claim 2 , wherein the body in the end use shape operatively adjusts an angular relationship between the first bone and second bone. 
     
     
         10 . The cage according to  claim 1 , wherein the space comprises the disk space between adjacent vertebrae. 
     
     
         11 . The cage according to  claim 10 , wherein the body is load bearing. 
     
     
         12 . The cage according to  claim 8 , wherein the contraction of the first engagement plate and the second engagement plate is operable to create compressive forces (a) between the first engagement plate and the first leg and (b) the second engagement plate and the second leg. 
     
     
         13 . The cage according to  claim 8 , wherein the movement of the first engagement plate and the second engagement plate away from each other is operable to create a thrust force when the first leg and the second leg are secured. 
     
     
         14 . The cage according to  claim 2 , further comprising:
 a closeout comprised of shape memory material disposed on the first engagement plate, wherein, upon the application of energy to the body, the closeout extends and contacts the second engagement plate, thereby closing out and retaining bone graft material in a cavity disposed between the first and second engagement plates.   
     
     
         15 . The cage according to  claim 14 , wherein the closeout is load bearing. 
     
     
         16 . The cage according to  claim 2 , wherein the first leg and the second leg comprise shape memory material and are adapted to transition to an end use shape upon the application of energy thereto. 
     
     
         17 . The cage according to  claim 16 , wherein, upon the application of energy thereto, the first leg moves toward the first engagement plate and the second leg moves toward the second engagement plate. 
     
     
         18 . The cage according to  claim 17 , wherein the contraction of the first leg and the second leg is operable to create creates compressive forces (a) between the first leg and the first engagement plate, and (b) between the second leg and the second engagement plate. 
     
     
         19 . The cage according to  claim 2 , wherein the spacing member includes an extension section, and further wherein, upon the application of energy, the extension section is operable to increase the width of the spacing member. 
     
     
         20 . The cage according to  claim 19 , wherein the extension of the spacing member is operable to create distraction forces (a) between the first engagement plate and the first bone and (b) between the second engagement plate and the second bone. 
     
     
         21 - 26 . (canceled) 
     
     
         27 . The cage according to  claim 1 , wherein the first leg and the second leg comprise shape memory material and are adapted to transition to a shape including an end use shape upon the application of energy thereto. 
     
     
         28 . The cage according to  claim 27 , wherein, upon the application of energy thereto, the first leg moves toward a first engagement plate and the second leg moves toward a second engagement plate. 
     
     
         29 . The cage according to  claim 28 , wherein the contraction of the first leg and the second leg is operable to create (a) compressive forces between the first leg and the first engagement plate, and (b) compressive forces between the second leg and the second engagement plate. 
     
     
         30 - 33 . (canceled) 
     
     
         34 . A method of reorienting a first bone and second bone, comprising:
 a. providing an inter-vertebral cage comprising
 i. a body adapted for insertion into a space between the first bone and the second bone, wherein the the body comprises a first engagement plate, a second engagement plate, and a spacing member coupling the first engagement plate with the second engagement plate, 
 ii. a first leg secured to the body, and 
 iii. a second leg secured to the body; 
   b. fixating the first bone and a the second bone in a desired working position;   c. inserting the body into the space, wherein
 i. the space has a boundary comprising a first portion of the surface of the first bone and a first portion of the surface of the second bone, 
 ii. the first engagement plate faces the first portion of the surface of the first bone, and 
 iii. the second engagement plate faces the first portion of the surface of the second bone, and 
   d. inserting the first leg into the first bone and the second leg into the second bone such that the body resides between the first bone and the second bone, wherein
 (i) the first leg is inserted into the first bone at a second portion of the surface of the first bone, 
 (ii) the second portion of the surface of the first bone is exterior to the space, 
 (iii) the second leg is inserted into the second bone at a second portion of the surface of the second bone, and 
 (iv) the second portion of the surface of the second bone is exterior to the space. 
   
     
     
         35 . The method according to  claim 34 , wherein the body, first leg, and the second leg comprise shape memory material and are adapted to transition to an end use shape upon the application of energy thereto. 
     
     
         36 . The method according to  claim 35 , further comprising:
 e. applying energy to the first leg and the second leg, thereby forcing the first leg and second leg to move from the second shape to an end use shape, wherein the end use shape contracts (i) the first leg toward the first engagement plate to secure the cage to the first bone, and (ii) the second leg toward the second engagement plate to secure the cage to the second bones, and   f. applying energy to the cage, thereby transitioning the cage to the end use shape, wherein the end use shape moves the first bone and the second bone into a desired corrective position.   
     
     
         37 . The method of reorienting a first and second bone according to  claim 36 , further comprising:
 g. inserting bone graft material into a cavity of the cage to aid in fusing the first bone and the second bone together.   
     
     
         38 . The method of reorienting a first and second bone according to  claim 35 , further comprising:
 e. applying energy to the first leg and the second leg, thereby forcing the first leg and second leg to move from the second shape to an end use shape, wherein the end use shape contracts (i) the first leg toward the first engagement plate to secure the cage to the first bone, and (ii) the second leg toward the second engagement plate to secure the cage to the second bones, and   f. applying energy to the body of the cage to reorient the first bone and the second bone and further distract the first bone and the second bone.   
     
     
         39 - 40 . (canceled) 
     
     
         41 . The method of reorienting a first and second bone according to  claim 35 , further comprising:
 e. applying energy to the first leg and the second leg, thereby forcing the first leg and second leg to move from the second shape to an end use shape, wherein the end use shape contracts (i) the first leg toward the first engagement plate to secure the cage to the first bone, and (ii) the second leg toward the second engagement plate to secure the cage to the second bones, and   f. applying energy to the body of the cage, thereby forcing the body to move from the second shape to the end use shape, wherein the end use shape contracts the first bone and the second bone, and restrains the first bone and the second bone in the contracted position.   
     
     
         42 - 53 . (canceled) 
     
     
         54 . The cage according to  claim 1 , wherein the space comprises the joint space between adjacent bones. 
     
     
         55 . The cage according to  claim 54 , wherein the body is load bearing. 
     
     
         56 . The cage according to  claim 1 , wherein the space comprises a cut or fracture between adjacent segments of a bone. 
     
     
         57 . The cage according to  claim 56 , wherein the body is load bearing.