Expandable lumbar cage and method for inserting the same

Abstract

Provided is an expandable lumbar cage including an upper member, a lower member, a sagittal adjustment unit to adjust sagittal balance of a spine, and a coronal adjustment unit to adjust coronal balance of the spine. According to the foregoing description, it is possible to simultaneously adjust the sagittal balance of the spine as well as the coronal balance, thereby achieving effective treatment of the spine having compound deformity.

1 . An expandable lumbar cage, comprising:
 an upper member;   a lower member spaced apart below the upper member;   a sagittal adjustment unit disposed between the upper member and the lower member, to adjust a distance between the upper member and the lower member, thereby adjusting sagittal balance of a spine; and   a coronal adjustment unit disposed between the upper member and the lower member and coupled to one side of each of the upper member and the lower member, to move up and down one side of each of the upper member and the lower member to adjust inclination of the upper member and the lower member, thereby adjusting coronal balance of the spine.   
     
     
         2 . The expandable lumbar cage according to  claim 1 , wherein the sagittal adjustment unit includes:
 a height adjustment screw positioned along a lengthwise direction of the upper member and the lower member, and having a screw thread on an outer peripheral surface, wherein an adjustment instrument is inserted into the height adjustment screw, and the height adjustment screw rotates with rotation of the adjustment instrument;   a height adjustment member screw-coupled to the height adjustment screw to move with the rotation of the height adjustment screw, with top in contact with a lower surface of the upper member and bottom in contact with an upper surface of the lower member, wherein the height adjustment member adjusts the distance between the upper member and the lower member by the movement; and   a support connection unit with one side connected to the height adjustment member and the other side connected to each of the upper member and the lower member to support the height adjustment member.   
     
     
         3 . The expandable lumbar cage according to  claim 2 , wherein the height adjustment member includes:
 an adjustment unit which moves by the rotation of the height adjustment screw screw-coupled to the adjustment unit through a screw coupling hole, with top in contact with the lower surface of the upper member and bottom in contact with the upper surface of the lower member, wherein the adjustment unit moves up and down the upper member and the lower member with the movement,   a support unit disposed on the other side of the upper member and the lower member to support the upper member and the lower member, and   a connection unit connecting the adjustment unit to the support unit.   
     
     
         4 . The expandable lumbar cage according to  claim 3 , wherein the adjustment unit includes:
 a first sliding surface which is formed with inclination, comes into contact with an upper slope surface formed on the lower surface of the upper member, and makes a sliding movement along the upper slope surface during movement, and   a second sliding surface which is formed with inclination, comes into contact with a lower slope surface formed on the upper surface of the lower member, and makes a sliding movement along the lower slope surface during movement, and   the adjustment unit is configured to move up and down the upper member and the lower member along the first sliding surface and the second sliding surface with the movement, to reduce or expand the distance between the upper member and the lower member.   
     
     
         5 . The expandable lumbar cage according to  claim 4 , wherein the adjustment unit is formed with each of the first sliding surface and the second sliding surface at a same slope angle with respect to a movement direction. 
     
     
         6 . The expandable lumbar cage according to  claim 5 , wherein the adjustment unit has the first sliding surface and the second sliding surface symmetrically disposed in a vertical direction, becomes narrower as it goes inward of the upper member and the lower member, and is configured to expand the distance between the upper member and the lower member as it moves inward. 
     
     
         7 . The expandable lumbar cage according to  claim 3 , wherein the upper member has a first slope surface upward sloping outwards on a lower surface of the other side end,
 the lower member has a second slope surface downward sloping outwards on an upper surface of the other side end opposite the first slope surface, and   the support unit has a first slope support surface corresponding to the first slope surface, and a second slope support surface corresponding to the second slope surface.   
     
     
         8 . The expandable lumbar cage according to  claim 3 , wherein the support unit has an insertion hole into which the adjustment instrument is inserted, and the insertion hole is coaxial with the screw coupling hole. 
     
     
         9 . The expandable lumbar cage according to  claim 3 , wherein the support connection unit includes:
 a connection axis coupled to the support unit,   a first support link with one side pivotably coupled to the connection axis and the other side pivotably coupled to the upper member, and   a second support link with one side pivotably coupled to the connection axis and the other side pivotably coupled to the lower member.   
     
     
         10 . The expandable lumbar cage according to  claim 1 , wherein the upper member is formed with a rectangular plan shape, and has an upper surface sloping downward from anterior to posterior of the spine with respect to a sagittal plane of the spine. 
     
     
         11 . The expandable lumbar cage according to  claim 10 , wherein the lower member is formed with a rectangular plan shape corresponding to the plan shape of the upper member, and has a lower surface sloping upward from anterior to posterior of the spine with respect to the sagittal plane of the spine. 
     
     
         12 . The expandable lumbar cage according to  claim 2 , wherein the coronal adjustment unit includes:
 a slope adjustment screw positioned along a lengthwise direction of the upper member and the lower member, and having a screw thread on an outer peripheral surface, wherein the adjustment instrument is inserted into the slope adjustment screw, and the slope adjustment screw rotates with rotation of the adjustment instrument,   a movement member formed in a tubular shape having a screw thread on an inner peripheral surface into which the slope adjustment screw is screw-coupled, wherein the movement member moves with the rotation of the slope adjustment screw, and   a slope adjustment unit with one side connected to the movement member, and the other side connected to each of the upper member and the lower member, to move up and down one side of the upper member and the lower member with the movement of the movement member.   
     
     
         13 . The expandable lumbar cage according to  claim 12 , wherein the slope adjustment unit includes:
 a pivot axis coupled to the movement member,   an upper link with one side pivotably coupled to the pivot axis and the other side coupled to one side of the upper member, and   a lower link with one side pivotably coupled to the pivot axis and the other side coupled to one side of the lower member.   
     
     
         14 . The expandable lumbar cage according to  claim 12 , further comprising:
 a guide unit disposed between the upper member and the lower member, and including a seating unit in which an end of the height adjustment screw and an end of the slope adjustment screw disposed opposite the end of the height adjustment screw are seated, to guide the height adjustment screw and the slope adjustment screw.   
     
     
         15 . The expandable lumbar cage according to  claim 12 , wherein the height adjustment screw, into which the adjustment instrument is inserted, rotates by the rotation of the adjustment instrument, and has a first adjustment hole having a polygonal cross-sectional shape, and
 the slope adjustment screw, into which the adjustment instrument is inserted, rotates by the rotation of the adjustment instrument, and has a second adjustment hole having a same diameter and cross-sectional shape as the first adjustment hole.   
     
     
         16 . The expandable lumbar cage according to  claim 15 , wherein the height adjustment screw and the slope adjustment screw are aligned such that the first adjustment hole and the second adjustment hole are coaxially arranged, and
 the adjustment instrument is configured to rotate at least one of the height adjustment screw or the slope adjustment screw according to an insertion depth.   
     
     
         17 . A method for inserting an expandable lumbar cage, comprising:
 inserting the expandable lumbar cage into an implantation space, the expandable lumbar cage including an upper member, a lower member spaced apart below the upper member, a sagittal adjustment unit disposed between the upper member and the lower member, to adjust a distance between the upper member and the lower member, thereby adjusting sagittal balance of a spine, and a coronal adjustment unit disposed between the upper member and the lower member to adjust inclination of the upper member and the lower member, thereby adjusting coronal balance of the spine;   adjusting the sagittal balance of the spine by expanding the distance between the upper member and the lower member with respect to a sagittal plane of the spine through the sagittal adjustment unit; and   adjusting the coronal balance of the spine by expanding the upper member and the lower member with inclination on one side with respect to a coronal plane of the spine through the coronal adjustment unit.   
     
     
         18 . The method for inserting an expandable lumbar cage according to  claim 17 , wherein inserting the expandable lumbar cage into the implantation space comprises inserting the expandable lumbar cage in a lateral position or anterolateral position of the spine. 
     
     
         19 . The method for inserting an expandable lumbar cage according to  claim 18 , wherein the sagittal adjustment unit and the coronal adjustment unit are respectively configured to adjust the sagittal balance and the coronal balance of the spine by a height adjustment screw and a slope adjustment screw which are coaxially aligned and rotate by an adjustment instrument, and
 adjusting the sagittal balance and the coronal balance comprises inserting the adjustment instrument using the height adjustment screw of one side of the expandable lumbar cage or the slope adjustment screw of the other side of the expandable lumbar cage, and rotating at least one of the height adjustment screw or the slope adjustment screw according to an insertion depth of the adjustment instrument with respect to the expandable lumbar cage to adjust the sagittal balance and the coronal balance.   
     
     
         20 . The method for inserting an expandable lumbar cage according to  claim 17 , wherein an upper surface of the upper member and a lower surface of the lower member are inclined with respect to the sagittal plane of the spine so that a height of one side of the expandable lumbar cage is higher than a height of the other side with respect to the sagittal plane of the spine, and
 inserting the expandable lumbar cage into the implantation space comprises placing the expandable lumbar cage such that one side of the expandable lumbar cage faces an anterior portion of the spine and inserting into the implantation space.