Expandable spinal interbody spacer and method of use

Abstract

An expandable spinal implant configured for positioning within a space between adjacent vertebral bodies includes an upper body, a lower body, a ratchet mechanism, and a plurality of bone screws. The upper body and lower body are pivotably affixed at a first end and are capable of movement relative to each other. The ratchet mechanism is slidably disposed on one of the upper and lower body and is capable of engaging the opposite one of the upper and lower body thereby permitting movement of the upper and lower body relative to each other in a first direction, but not in a second direction. An insertion instrument capable of being attached to the expandable spinal instrument and a method of performing spinal surgery is also disclosed.

What is claimed is: 
     
       1. A method of performing surgery, comprising:
 positioning an upper body and a lower body of a spinal implant in a first, approximated position relative to each other, the upper body and lower body pivotably coupled at a first end and capable of movement relative to each other, wherein each of the upper body and the lower body is dimensioned to be installed between first and second vertebral bodies, the outer surfaces of each of the upper body and the lower body are adapted to engage a corresponding end plate of the first and second vertebral bodies;
 preparing an intervertebral space between the first and second vertebral bodies to receive the spinal implant; 
   inserting the spinal implant into the prepared intervertebral space;   articulating the upper body and lower body relative to each other to effectuate a desired lordosis of a spine of the patient;   inserting a plurality of bone screws that are capable of being attached to bone through a plurality of screw holes defined through the outer surface and an adjacent side surface of the upper body and through the outer surface and an adjacent side surface of the lower body, wherein the screw holes are oriented towards a respective adjacent one of the first and second vertebral bodies at an oblique angle; and   locking a ratchet mechanism slidably disposed on one of the upper and lower bodies, to lock the position of the upper body and lower body relative to each other, the ratchet mechanism capable of engaging the opposite one of the upper and lower bodies thereby permitting movement of the upper and lower bodies relative to each other in a first direction, but not in a second direction.   
     
     
       2. The method of  claim 1 , wherein inserting the spinal implant includes first securing the spinal implant to an insertion device. 
     
     
       3. The method of  claim 1 , wherein locking the ratchet mechanism includes rotating a ratchet screw disposed within an annular groove defined within the upper body in a first direction, wherein the ratchet screw includes a head and a threaded shank extending therefrom, the ratchet screw being threadably engaged within a threaded through-bore defined through the ratchet mechanism, wherein rotating the ratchet screw effectuates movement of the ratchet mechanism in a first direction thereby causing the ratchet mechanism to engage the lower body and lock the position of the lower body relative to the upper body. 
     
     
       4. The method of  claim 1 , wherein positioning the upper body and lower body in a first, approximated, position includes engaging a first plurality of teeth defined on a surface of the ratchet mechanism with a second plurality of teeth defined on an opposing surface of the lower body, thereby permitting articulation of the upper body relative to the lower body in a first direction, but not in a second direction. 
     
     
       5. The method of  claim 4 , wherein locking the ratchet mechanism further includes further rotating the ratchet screw the first direction, thereby causing the first and second pluralities of teeth to further engage, thereby locking the position of the upper body and the lower body relative to each other. 
     
     
       6. The method of  claim 1 , further including packing a lumen defined in each of the upper body and lower body with bone in-growth material. 
     
     
       7. The method of  claim 1 , further including packing a lumen defined in each of the upper body and lower body with drugs. 
     
     
       8. The method of  claim 1 , wherein positioning the upper body and lower body includes positioning the upper body and lower body in a desired articulated position relative to each other. 
     
     
       9. A method of performing surgery, comprising:
 inserting an expandable intervertebral implant into an intervertebral space between an upper vertebral body and a lower vertebral body, the expandable intervertebral implant including:
 an upper body and a lower body articulatable relative to each other in a first direction away from one another and a second direction towards one another, the upper and lower bodies being articulatable to a plurality of articulated arrangements in each of which the upper and lower bodies are positioned to define a different respective angle therebetween; and 
 a locking mechanism movable independently of articulating the upper and lower bodies relative to each other between an unlocked configuration and a locked configuration, wherein, when the locking mechanism is in the locked configuration, the locking mechanism locks the positions of the upper and lower bodies relative to each other in any one of the plurality of articulated arrangements with the respective angle therebetween, wherein, when the locking mechanism is in the unlocked configuration, the upper body and lower body are articulatable freely in both the first and second directions, and wherein a portion of the locking mechanism translates along a linear axis without rotating when the locking mechanism moves between the unlocked and locked configurations.  
   
     
     
       10. The method of  claim 9 , wherein the upper body includes a first screw passage extending through an outer surface thereof and configured to receive a first screw arranged to extend from the implant into an adjacent upper vertebral body, and wherein the lower body includes a second screw passage extending through an outer surface thereof and configured to receive a second screw arranged to extend from the implant into an adjacent lower vertebral body.  
     
     
       11. The method of  claim 10 , wherein the first and second screw passages extend at respective oblique angles through the outer surfaces of the respective upper and lower bodies.  
     
     
       12. The method of  claim 10 , further comprising inserting the first and second screws through the respective first and second screw passages and into the respective upper and lower bodies.  
     
     
       13. The method of  claim 9 , wherein the locking mechanism includes an actuation screw rotatable to move the locking mechanism between the unlocked and locked configurations.  
     
     
       14. The method of  claim 9 , wherein the locking mechanism includes teeth for engaging corresponding teeth of the upper body or the lower body when the locking mechanism is in the locked configuration.  
     
     
       15. The method of  claim 9 , wherein at least one of the upper and lower bodies includes guiding structure for guiding the portion of the locking mechanism to translate along the linear axis.  
     
     
       16. The method of  claim 9 , wherein the portion of the locking mechanism translates along a pin of the implant when the locking mechanism moves between the unlocked and locked configurations, the pin having a longitudinal axis extending parallel to the linear axis.  
     
     
       17. The method of  claim 9 , wherein the upper and lower bodies are articulatable relative to each other about a hinge positioned in a distal region of the implant.  
     
     
       18. The method of  claim 17 , wherein one of the upper and lower bodies has a projecting portion in a proximal region of the implant, the projecting portion being received within a recessed portion of the other of the upper and lower bodies in the proximal region of the implant.  
     
     
       19. The method of  claim 18 , wherein articulating the upper and lower bodies relative to each other in the first direction causes the projecting portion to withdraw from the recessed portion, and wherein articulating the upper and lower bodies relative to each other in the second direction causes the projecting portion to advance into the recessed portion.  
     
     
       20. The method of  claim 17 , wherein the locking mechanism is positioned in a proximal region of the implant.  
     
     
       21. The method of  claim 20 , wherein the linear axis extends along a proximal-distal direction.  
     
     
       22. The method of  claim 21 , wherein the portion of the locking mechanism is a ratchet having a T-shaped profile in a plane orthogonal to the linear axis.  
     
     
       23. The method of  claim 17 , wherein a proximal region of the implant includes an attachment interface for securing the implant to an insertion instrument.  
     
     
       24. The method of  claim 23 , wherein the attachment interface includes at least one threaded bore.  
     
     
       25. The method of  claim 9 , further comprising:
 articulating the upper body and the lower body relative to each other in the first direction to effectuate a desired lordosis of a spine of a patient; and   moving the locking mechanism to the locked configuration to lock the positions of the upper and lower bodies relative to each other.    
     
     
       26. A method of performing surgery, comprising:
 inserting an expandable intervertebral implant into an intervertebral space between an upper vertebral body and a lower vertebral body, the expandable intervertebral implant including:
 an upper body and a lower body articulatable relative to each other in a first direction away from one another and a second direction towards one another, the upper and lower bodies being articulatable to a plurality of articulated arrangements in each of which the upper and lower bodies are positioned to define a different respective angle therebetween; and 
 a locking mechanism movable between an unlocked configuration and a locked configuration, wherein, when the locking mechanism is in the locked configuration, the locking mechanism locks the positions of the upper and lower bodies relative to each other in any one of the plurality of articulated arrangements with the respective angle therebetween, and wherein, when the locking mechanism is in the unlocked configuration, the upper body and lower body are articulatable freely in both the first and second directions; 
 wherein the locking mechanism is movable to an engaged configuration, wherein, when the locking mechanism is in the engaged configuration, the locking mechanism prevents the upper and lower bodies from articulating relative to each other in the second direction while permitting the upper and lower bodies to articulate relative to each other in the first direction.  
   
     
     
       27. The method of  claim 26 , wherein the locking mechanism is a ratchet having teeth for engaging corresponding teeth of the upper body or the lower body when the locking mechanism is in both the locked configuration and the engaged configuration.  
     
     
       28. The method of  claim 26 , further comprising:
 articulating the upper body and the lower body relative to each other in the first direction to effectuate a desired lordosis of a spine of a patient; and   moving the locking mechanism to the locked configuration to lock the positions of the upper and lower bodies relative to each other.