Crossbar spinal prosthesis having a modular design and related implantation methods

Abstract

Modular spinal prosthesis having one of both of adaptable and configurable components are provided. The modular spinal prosthesis described herein provide an artificial articular configuration to replace damaged, worn or otherwise removed spinal facet elements.

1 . A facet joint prosthesis to replace, on a vertebral body, a portion of a natural facet joint, comprising: 
 a support component sized to span a portion of the vertebral body and adapted to receive a pair of prosthetic facet elements; and    a pair of prosthetic facet elements positionable relative to the support component to replace a portion of a natural facet joint.    
   
   
       2 . A facet joint prosthesis according to  claim 1  wherein the support component is sized to span a portion of a vertebral body is between a left lamina and a right lamina.  
   
   
       3 . A facet joint prosthesis according to  claim 1  wherein the support component is sized to span a portion of a vertebral body is between the left pedicle and the right pedicle.  
   
   
       4 . A facet joint prosthesis according to  claim 1  further comprising a kit comprising a plurality of support components having different lengths.  
   
   
       5 . A facet joint prosthesis according to  claim 1  wherein the support component is further adapted to have an adjustable width.  
   
   
       6 . A facet joint prosthesis according to  claim 1  wherein the support component is secured to the vertebral body.  
   
   
       7 . A facet joint prosthesis according to  claim 1  wherein the support component is secured to an adjacent vertebral body.  
   
   
       8 . A facet joint prosthesis according to  claim 1  wherein the pair of prosthetic facet elements are positioned relative to the support component to provide a symmetric anatomical solution.  
   
   
       9 . A facet joint prosthesis according to  claim 1  wherein the pair of prosthetic facet elements are positioned relative to the support component to provide an asymmetric anatomical solution.  
   
   
       10 . A facet joint prosthesis according to  claim 1  wherein the support component has an opening adapted to receive the prosthetic facet elements.  
   
   
       11 . A facet joint prosthesis according to  claim 1  wherein the prosthetic facet elements are slideable along the width of the support component.  
   
   
       12 . A facet joint prosthesis according to  claim 1  wherein the prosthetic facet elements may be fixed in a pre-ordained position medial of the typical a typical anatomic location.  
   
   
       13 . A facet joint prosthesis according to  claim 1  wherein the prosthetic facet elements may be fixed in a pre-ordained position lateral of the typical a typical anatomic location.  
   
   
       14 . A facet joint prosthesis according to  claim 1  wherein the ends of the support component are adapted to receive an opening in each of the pair of prosthetic facet elements.  
   
   
       15 . A facet joint prosthesis according to  claim 14  wherein each of the pair of prosthetic facet elements is selected from a plurality of prosthetic facet elements each having an opening with a different depth.  
   
   
       16 . A facet joint prosthesis according to  claim 1  further comprising evenly distributing the weight on the vertebral body using the support component.  
   
   
       17 . A facet joint prosthesis according to  claim 1  wherein the pair of prosthetic facet elements are further adapted to be adjustable relative to the support component.  
   
   
       18 . A facet joint prosthesis according to  claim 1  wherein the pair of prosthetic facet elements are caudal facet elements.  
   
   
       19 . A facet joint prosthesis according to  claim 1  wherein the pair of prosthetic facet elements are cephalad facet elements.  
   
   
       20 . An adaptable spinal facet joint prosthesis, comprising: 
 a crossbar having a first end and a second end;    a pair of cephalad prosthesis elements each having a bone engaging end and an end adapted to couple to the crossbar; and    a pair of caudal prosthesis elements each having a surface adapted to receive a crossbar end and a fixation element.    
   
   
       21 . The adaptable spinal facet joint prosthesis according to  claim 20  wherein the distance between the crossbar first end and second end is adjustable.  
   
   
       22 . An adaptable spinal facet joint prosthesis according to claim Al wherein the crossbar first end and second end have a round surface to engage with the caudal prosthesis surface adapted to receive a crossbar end.  
   
   
       23 . An adaptable spinal facet joint prosthesis according to  claim 20  wherein the bone engaging end of at least one of the pair of cephalad prosthesis elements is disengagably coupled to the at least one of the pair of cephalad prosthesis elements.  
   
   
       24 . An adaptable spinal facet joint prosthesis according to  claim 23  wherein the bone engaging end is adapted to receive one of a plurality of bone engaging ends each one of said plurality of bone engaging ends having a different length.  
   
   
       25 . An adaptable spinal facet joint prosthesis according to  claim 20  wherein at least one of the pair of cephalad prosthesis elements or at least one of the pair of caudal prosthesis elements comprises an anti-rotation feature.  
   
   
       26 . An adaptable spinal facet joint prosthesis according to  claim 20  wherein further comprising a crossbar mount having a crossbar engaging portion and a cephalad prosthesis element engaging portion.  
   
   
       27 . An adaptable spinal facet joint prosthesis according to  claim 26  wherein the crossbar passes through the crossbar engaging portion.  
   
   
       28 . An adaptable spinal facet joint prosthesis according to  claim 26  wherein the crossbar is attached to the crossbar engaging portion.  
   
   
       29 . An adaptable spinal facet joint prosthesis according to  claim 26  wherein when the crossbar is connected to the crossbar engaging portion, the crossbar mount may be rotated about the crossbar.  
   
   
       30 . An adaptable spinal facet joint prosthesis according to  claim 26  wherein the crossbar may move to change an angle formed by the crossbar mount, the crossbar and a cephalad prosthesis element coupled to the crossbar mount cephalad prosthesis element engaging portion.  
   
   
       31 . An adaptable spinal facet joint prosthesis according to  claim 26  wherein the height above the crossbar of a part of a cephalad prosthesis element may be adjusted by moving the cephalad prosthesis element relative to the crossbar cephalad prosthesis portion engaging portion.  
   
   
       32 . An adaptable spinal facet joint prosthesis according to  claim 26  wherein the crossbar mount posterior height is less than the posterior height of an adjacent spinous process when the adaptable spinal facet joint is implanted in a body.  
   
   
       33 . An adaptable spinal facet joint prosthesis according to  claim 20  wherein the pair of cephalad prosthesis element ends adapted to couple to the crossbar are separated from the crossbar by at least one additional element.  
   
   
       34 . A spinal prosthesis, comprising: 
 a first cephalad prosthesis element and a second cephalad prosthesis element;    a first caudal prosthesis and a second caudal prosthesis; and    a crossbar element connected to the first and second cephalad prosthesis elements, the crossbar element having a first end in contact with the first caudal prosthesis and a second end in contact with the second prosthesis wherein at least one of the first cephalad prosthesis element, the second cephalad prosthesis element, the caudal prosthesis, the second caudal prosthesis, and the crossbar element having a configurable portion.    
   
   
       35 . A spinal prosthesis according to  claim 34  wherein the configurable portion is part of the first cephalad prosthesis element or the second cephalad prosthesis element.  
   
   
       36 . A spinal prosthesis according to  claim 35  wherein the configurable portion is the height or the first or the second cephalad prosthesis element relevant to the crossbar element.  
   
   
       37 . A spinal prosthesis according to  claim 35  wherein the configurable portion is the angle form between the first cephalad prosthesis element and the crossbar element for the angle form between the second cephalad prosthesis element and the crossbar element.  
   
   
       38 . A spinal prosthesis according to  claim 35  wherein the configurable portion is the angle form between an axial plane passing through the-crossbar element and either the first cephalad prosthesis element or the second cephalad prosthesis element.  
   
   
       39 . A spinal prosthesis according to  claim 38  wherein the angle form between the first cephalad prosthesis element and an axial plane passing through the crossbar element is the same as the angle form between the second cephalad prosthesis element and an axial plane passing through the crossbar element.  
   
   
       40 . A spinal prosthesis according to  claim 35  wherein the first and second cephalad prosthesis element comprised an arm, an elbow and a stem wherein the arm has a crossbar engaging end and is attached to the elbow and the stem has a distal tip and is attached to the elbow and the shape of the elbow defines an arm-stem angle.  
   
   
       41 . A spinal prosthesis according to  claim 40  wherein the shape of the elbow defines an arm-stem angle of 90°.  
   
   
       42 . A spinal prosthesis according to  claim 34  wherein the configurable portion is part of the first caudal prosthesis element or the second caudal prosthesis element.  
   
   
       43 . A spinal prosthesis according to  claim 42  wherein the configurable portion is an angle formed between the crossbar element first end and the first caudal prosthesis.  
   
   
       44 . A spinal prosthesis according to  claim 42  wherein the configurable portion is an angle formed between the crossbar element second end and the second caudal prosthesis.  
   
   
       45 . A spinal prosthesis according to  claim 42  wherein the first and the second caudal prosthesis each comprise a caudal stem having a distal end and a head; a caudal bearing surface to contact a crossbar element and a feature adapted to engage the caudal stem head.  
   
   
       46 . A spinal prosthesis according to  claim 45  wherein the caudal bearing feature is adapted to alter an angle formed between the caudal bearing surface and a plane passing through the caudal bearing when the caudal stem head is engaged with the caudal bearing feature.  
   
   
       47 . A spinal prosthesis according to  claim 45  wherein the feature adapts to engage the caudal stem head and the caudal stem head engage using friction fit.  
   
   
       48 . A spinal prosthesis, comprising: 
 a pair of cephalad prosthesis members each comprising a distal end for securing to a portion of the spine and a proximal end comprising a bearing element;    a pair of caudal prosthesis members each comprising a fixation element for securing to a portion of a spine and a bearing element adapting to engage the cephalad prosthesis member bearing element; and    a crossbar connected between the cephalad prosthesis members.    
   
   
       49 . A spinal prosthesis according to  claim 48  wherein the caudal prosthesis member bearing element has a surface configured for reflexion between the cephalad prosthesis member bearing element and the caudal prosthesis bearing element.  
   
   
       50 . A spinal prosthesis according to  claim 48  wherein the caudal prosthesis member bearing element has a surface configured for extension between the cephalad prosthesis member bearing element and the caudal prosthesis bearing element.  
   
   
       51 . A spinal prosthesis according to  claim 48  wherein the caudal prosthesis member bearing element has a surface configured for reflexion and extension between the cephalad prosthesis bearing element and the caudal prosthesis bearing element.  
   
   
       52 . A spinal prosthesis according to  claim 48  wherein the caudal prosthesis member bearing element has a surface configured for lateral bending between the cephalad prosthesis member bearing element and the caudal prosthesis bearing element.  
   
   
       53 . A spinal prosthesis according to  claim 48  wherein the caudal prosthesis member bearing element has a surface configured for axial rotation between the cephalad prosthesis member bearing element and the caudal prosthesis bearing element.  
   
   
       54 . A spinal prosthesis according to  claim 48  wherein in the caudal prosthesis member bearing element has a surface configured for both axial rotation and lateral bending between the cephalad prosthesis member bearing element and the caudal prosthesis bearing element.  
   
   
       55 . A spinal prosthesis according to  claim 48  wherein in the distal end of each of the pair of cephalad prosthesis members is secured to a first vertebrae and the fixation element of each of the pair of caudal prosthesis members is secured to a second vertebrae and the caudal prosthesis bearing element has a surface configured to accommodate reflexion between the first vertebrae and the second vertebrae.  
   
   
       56 . A spinal prosthesis according to  claim 48  wherein in the distal end of each of the pair of cephalad prosthesis members is secured to a first vertebrae and the fixation element of each of the pair of caudal prosthesis members is secured to a second vertebrae and the caudal prosthesis bearing element has a surface configured to accommodate extension between the first vertebrae and the second vertebrae.  
   
   
       57 . A spinal prosthesis according to  claim 48  wherein in the distal end of each of the pair of cephalad prosthesis members is secured to a first vertebrae and the fixation element of each of the pair of caudal prosthesis members is secured to a second vertebrae and the caudal prosthesis bearing element has a surface configured to accommodate reflexion and extension between the first vertebrae and the second vertebrae.  
   
   
       58 . A spinal prosthesis according to  claim 48  wherein in the distal end of each of the pair of cephalad prosthesis members is secured to a first vertebrae and the fixation element of each of the pair of caudal prosthesis members is secured to a second vertebrae and the caudal prosthesis bearing element has a surface configured to accommodate lateral bending between the first vertebrae and the second vertebrae.  
   
   
       59 . A spinal prosthesis according to  claim 48  wherein in the distal end of each of the pair of cephalad prosthesis members is secured to a first vertebrae and the fixation element of each of the pair of caudal prosthesis members is secured to a second vertebrae and the caudal prosthesis bearing element has a surface configured to accommodate axial rotation between the first vertebrae and the second vertebrae.  
   
   
       60 . A spinal prosthesis according to  claim 48  wherein in the distal end of each of the pair of cephalad prosthesis members is secured to a first vertebrae and the fixation element of each of the pair of caudal prosthesis members is secured to a second vertebrae and the caudal prosthesis bearing element has a surface configured to accommodate both axial rotation and lateral bending between the first vertebrae and the second vertebrae.  
   
   
       61 . A spinal prosthesis according to  claim 48  wherein the crossbar is connected between the cephalad prosthesis member bearing elements.  
   
   
       62 . A spinal prosthesis according to  claim 48  wherein the crossbar is connected by attaching to a portion of the cephalad prosthesis member adjacent to the cephalad prosthesis bearing element.