Adjustable Spinal Implant

Abstract

An expansion assembly expands a vertebral implant. The vertebral implant has an inner cylindrical assembly adapted for insertion into an outer cylindrical assembly having an outer wall. The vertebral implant is expandable along an implant axis defined by the outer and inner cylindrical assemblies. The expansion assembly comprises an axle having proximal and distal end portions and an axle axis defined between the proximal and distal end portions. The expansion assembly further comprises a gear arranged about the axle axis at the proximal end portion of the axle and adapted to rotate about the axle axis to cause the inner cylindrical assembly to expand the vertebral implant. The engagement assembly also comprising a first engaging portion adapted to engage the inner cylindrical assembly and a second engaging portion adapted to engage the gear externally of the outer wall of the outer cylindrical assembly.

1 . A vertebral implant for expansion between two vertebral bodies, comprising:
 a first end plate component including a first cylindrical portion, the first cylindrical portion comprising a first threaded surface;   a second end plate component including a second cylindrical portion, the second cylindrical portion comprising a second threaded surface; and   a tubular body comprising a first end portion and a second end portion and including a central hollow bore, the tubular body having a longitudinally extending axis, the tubular body having a threaded surface at the first end portion and at the second end portion,
 the threaded surface at the first end portion threadably engaging the first threaded surface of the first end plate, the threaded surface at the second end portion threadably engaging the second threaded surface of the second end plate, 
 the tubular body comprising a plurality of apertures extending from an exterior of tubular body to the hollow bore, the plurality of apertures being sized and configured to receive a driving tool, the plurality of apertures being arranged in at least adjacent first and second rows, the first row and the second row being axially offset along the longitudinal axis, the plurality of apertures of the first row also being radially offset from the plurality of apertures of the second row. 
   
     
     
         2 . The vertebral implant of  claim 1 , wherein the plurality of apertures are further arranged in a third row, the third row being axially offset along the longitudinal axis from both the first row and the second row and located such that the second row is disposed between and adjacent to both the first and third rows, the plurality of apertures of the third row being radially offset from the plurality of apertures of the second row and being radially aligned with the plurality of apertures of the first row. 
     
     
         3 . The vertebral implant of  claim 1 , wherein the first threaded surface of the first end plate is an inwardly facing surface and wherein the second threaded surface of the second end plate is an inwardly facing surface. 
     
     
         4 . The vertebral implant of  claim 3 , wherein the threaded body surface is an outwardly facing surface. 
     
     
         5 . The vertebral implant of  claim 4 , wherein the plurality of apertures are formed through threads on the threaded outer facing surface of the tubular body. 
     
     
         6 . The vertebral implant of  claim 1 , wherein each of the first and second end plates includes a flange sized to fit against a substantial load bearing portion of a vertebral endplate. 
     
     
         7 . The vertebral implant of  claim 6 , wherein the flange and the cylindrical portions are integrally formed. 
     
     
         8 . The vertebral implant of  claim 1 , wherein the threads on the threaded surface of the tubular body extend substantially along a length of the tubular body from the first end portion to the second end portion. 
     
     
         9 . The vertebral implant of  claim 1 , wherein the threads on the threaded surface of the tubular body are cut in opposite directions such that the endplates can be drawn together or apart by rotating only the tubular body. 
     
     
         10 . The vertebral implant of  claim 1 , wherein the threads at the first end portion and at the second end portion of the tubular body are cut in the same direction. 
     
     
         11 . The vertebral implant of  claim 1 , wherein the flange comprises a flange bore extending therethrough, the flange bore being in communication with the hollow bore of the tubular member. 
     
     
         12 . A vertebral implant for expansion between two vertebral bodies, comprising:
 a first end plate component including a first cylindrical portion, the first cylindrical portion comprising a first threaded surface; and   a tubular body comprising a first end portion and a second end portion, the tubular body having a longitudinally extending axis, the tubular body having a threaded surface at the first end portion, the threaded surface at the first end portion threadably engaging the first threaded surface of the first end plate,   the tubular body comprising a plurality of apertures extending inwardly from an exterior of tubular body, the plurality of apertures being sized and configured to receive a driving tool, the plurality of apertures being arranged in at least adjacent first and second rows, the first row and the second row being axially offset along the longitudinal axis, the plurality of apertures of the first row also being radially offset from the plurality of apertures of the second row.   
     
     
         13 . The vertebral implant of  claim 12 , comprising a second end plate component associated with the second end portion of the tubular body. 
     
     
         14 . The vertebral implant of  claim 12 , wherein the plurality of apertures are further arranged in a third row, the third row being axially offset along the longitudinal axis from both the first row and the second row and located such that the second row is disposed between and adjacent to both the first and third rows, the plurality of apertures of the third row being radially offset from the plurality of apertures of the second row and also being radially aligned with the plurality of apertures of the first row. 
     
     
         15 . The vertebral implant of  claim 12 , wherein the first threaded surface is an inwardly facing surface. 
     
     
         16 . The vertebral implant of  claim 15 , wherein the threaded body surface is an outer facing surface. 
     
     
         17 . The vertebral implant of  claim 16 , wherein the plurality of apertures are formed through threads on the threaded outer facing surface of the tubular body. 
     
     
         18 . A vertebral implant for expansion between two vertebral bodies, comprising:
 a first end plate component including a first flange and a first cylindrical portion, the first cylindrical portion comprising an inwardly facing first threaded surface, the first flange being sized to fit against a substantial load bearing portion of an upper vertebral endplate;   a second end plate component including a second flange and a second cylindrical portion, the second cylindrical portion comprising an inwardly facing second threaded surface, the second flange being sized to fit against a substantial load bearing portion of a lower vertebral endplate;   a tubular body comprising a first end portion and a second end portion and including a central hollow bore, the tubular body having a longitudinally extending axis, the tubular body having an outwardly facing threaded surface extending from the first end portion to the second end portion,
 the outer facing threaded surface at the first end portion threadably engaging the inwardly facing first threaded surface of the first end plate, the outer facing threaded surface at the second end portion threadably engaging the inwardly facing second threaded surface of the second end plate, 
 the tubular body comprising a plurality of apertures extending through the outwardly facing threads on the exterior of the tubular body to the hollow bore, the plurality of apertures being sized and configured to receive a driving tool, the plurality of apertures being arranged in at least first, second, and third rows, the second row being adjacent both the first and third rows, the first, second, and third rows being axially offset along the longitudinal axis, the plurality of apertures of the second row also being radially offset from the plurality of apertures of the first row and the third row, the plurality of apertures of the third row being radially aligned with the plurality of apertures of the first row. 
   
     
     
         19 . The vertebral implant of  claim 18 , wherein the flange and the cylindrical portions are integrally formed. 
     
     
         20 . The vertebral implant of  claim 18 , wherein each of the first and second end plate components comprises a bore extending therethrough, the bore being in communication with the hollow bore of the tubular member.