Intervertebral implant and associated method

Abstract

An intervertebral implant and associated method. The intervertebral implant can include a first component having a first articulating surface and a first bone engagement surface for engaging a first vertebra, and a second component having a second articulating surface and a second bone engagement surface for engaging a second vertebra adjacent to the first vertebra. The first and second articulating surfaces can articulate with each other for substantially replicating a natural spinal movement. The first and second bone engagement surfaces can define an outer surface substantially shaped as an envelope of two intersecting cylinders. In one aspect, the first and second articulating surfaces can have substantially equal radii of curvature in a coronal plane and different radii of curvature in a sagittal plane.

1 . An intervertebral implant comprising:
 a first component having a first articulating surface and a first bone engagement surface for engaging a first vertebra; and   a second component having a second articulating surface and a second bone engagement surface for engaging a second vertebra adjacent to the first vertebra, wherein the second articulating surface contacts and articulatably moves relative to the first articulating surface for substantially replicating a natural spinal movement, wherein the first and second articulating surfaces have substantially equal radii of curvature in a coronal plane and different radii of curvature in a sagittal plane, and wherein the first and second bone engagement surfaces define an outer surface substantially shaped as an envelope of two intersecting cylinders.   
     
     
         2 . The intervertebral implant of  claim 1 , wherein each of the first and second bone engagement surfaces comprises a pair of separate convex end portions connected with a concave intermediate portion. 
     
     
         3 . The intervertebral implant of  claim 2 , further comprising bone engagement formations arranged in substantially parallel rows on the first and second bone engagement surfaces. 
     
     
         4 . The intervertebral implant of  claim 1 , wherein the first articulating surface includes a concave portion in the coronal and sagittal plane, and the second articulating surface includes a convex portion in the coronal and sagittal plane. 
     
     
         5 . The intervertebral implant of  claim 2 , in combination with an insertion cannula preloaded with the intervertebral implant, the insertion cannula defining a longitudinal bore, the longitudinal bore shaped to mate with the outer surface of the implant. 
     
     
         6 . The combination of  claim 5 , further comprising a retainer removably coupled to a proximal end of the insertion cannula, the retainer removably retaining the intervertebral implant within the longitudinal bore. 
     
     
         7 . The combination of  claim 6 , wherein the retainer includes a head and first and second compliant arms extending from the head, the arms received in a diametrical slot defined at the proximal end of the cannula, the arms engageable to the concave intermediate portions of the intervertebral implant for retaining the intervertebral implant in the insertion cannula. 
     
     
         8 . An intervertebral implant comprising:
 a first component having a first bone engagement surface engageable with a first vertebra, and a first articulating surface; and   a second component having a second bone engagement surface engageable with a second vertebra and a second articulating surface, wherein the first and second articulating surfaces contact and move relative to one another during implantation permitting relative motion between the first and second vertebrae, wherein the first and second articulating surfaces have substantially equal radii of curvature in a coronal plane and different radii of curvature in a sagittal plane, and wherein the first and second bone engagement surfaces define an outer surface substantially shaped as an envelope of two intersecting cylinders when the first and second articulating surfaces are in direct contact with one another.   
     
     
         9 . The intervertebral implant of  claim 8 , wherein each of the first and second bone engagement surfaces comprises a pair of separate convex end portions connected with a concave intermediate portion. 
     
     
         10 . The intervertebral implant of  claim 8 , wherein the first articulating surface includes a concave portion in the coronal and sagittal plane, and the second articulating surface includes a convex portion in the coronal and sagittal plane. 
     
     
         11 . The intervertebral implant of  claim 8 , further comprising bone engagement formations arranged in substantially parallel rows on the first and second bone engagement surfaces. 
     
     
         12 . The intervertebral implant of  claim 9 , in combination with an insertion cannula defining a longitudinal bore, the longitudinal bore shaped to mate with the outer surface of the implant. 
     
     
         13 . The combination of  claim 12 , further comprising a retainer removably coupled to a proximal end of the insertion cannula, the retainer removably retaining the intervertebral implant within the longitudinal bore. 
     
     
         14 . The combination of  claim 13 , wherein the retainer includes a head and first and second compliant arms extending from the head, the arms received in a diametrical slot defined at the proximal end of the cannula, the arms engageable to the concave intermediate portions of the intervertebral implant for retaining the intervertebral implant in the insertion cannula. 
     
     
         15 . An intervertebral implant comprising:
 a first component having a first articulating surface and a first bone engagement surface for engaging a first vertebra; and   a second component having a second articulating surface and a second bone engagement surface for engaging a second vertebra adjacent to the first vertebra, wherein the second articulating surface contacts and articulatably moves relative to the first articulating surface for substantially replicating a natural spinal movement, wherein the first articulating surface comprises a convex portion in the coronal plane and a concave portion in the sagittal plane, and the second articulating surface includes a concave portion in the coronal plane and convex portion in the sagittal plane, and wherein the first and second bone engagement surfaces define an outer surface substantially shaped as an envelope of two intersecting cylinders.   
     
     
         16 . The intervertebral implant of  claim 15 , wherein in the sagittal plane the curvatures of the respective convex and concave portions of the first and second articulating surfaces are different. 
     
     
         17 . The intervertebral implant of  claim 15 , wherein in the coronal plane the first articulating surface is substantially V-shaped with a rounded tip. 
     
     
         18 . The intervertebral implant of  claim 15 , further comprising bone engagement formations arranged in substantially parallel rows on the first and second bone engagement surfaces. 
     
     
         19 . The intervertebral implant of  claim 15  in combination with an insertion cannula preloaded with the intervertebral implant, the insertion cannula defining a longitudinal bore, the longitudinal bore shaped to mate with the outer surface of the implant. 
     
     
         20 . The combination of  claim 19 , further comprising a retainer removably coupled to a proximal end of the insertion cannula, the retainer removably retaining the intervertebral implant within the longitudinal bore.