Vertebral implants adapted for posterior insertion

Abstract

Disclosed is an endoprosthetic implant for a human spinal disc. The structure of the implant allows it to be inserted posteriorly. This insertion is accomplished by performing a partial discectomy in the affected region. An intervertebral space is then created by removing the fibrocartilage between the facing surfaces of adjacent vertebrae. The implant is then inserted into the intervertebral space. The implant is thus adapted to replace damaged or worn intervertebral discs. Furthermore, the structure of the implant, and its posterior insertion, alleviate most spinal pathologies.

1 . A vertebral implant for insertion between adjacent vertebrae having anterior and posterior faces comprising:
 a superior support positioned upon a vertebral surface, the superior support having a posterior edge which is flush with a posterior vertebral face, the superior support having an arcuate trough formed therein;   an inferior support positioned upon a vertebral surface in facing relation to the superior support such that a posterior edge of the inferior support is flush with a posterior vertebral face, the interior support having an arcuate trough formed therein;   a two part shell positioned intermediate the superior and inferior supports, the two part shell having arcuate upper and lower surfaces that correspond to the arcuate troughs formed within the superior and inferior supports;   a threaded screw positioned within the two part shell, rotation of the screw causing its lateral movement to thereby adjust the spacing between the two parts of the shell.   
   
   
       2 . A vertebral implant for insertion into an intervertebral space having anterior and posterior areas comprising:
 superior and inferior supports positioned upon a vertebral surface in facing relation to one another, both supports being positioned in the posterior area of the intervertebral space;   an insert positioned intermediate the superior and inferior supports, the insert adapted to absorb forces generated in the intervertebral space.   
   
   
       3 . The implant as described in  claim 2  wherein the insert is formed from upper and lower portions. 
   
   
       4 . The implant as described in  claim 3  wherein the upper and lower portions are interconnected via a threaded element, wherein movement of the threaded element causes relative movement of the upper and lower portions. 
   
   
       5 . The implant as described in  claim 2  wherein the superior and inferior supports each include lips that are adapted to hang over an edge of the vertebral body. 
   
   
       6 . A vertebral implant specifically adapted for posterior insertion comprising:
 a superior support positioned upon a vertebral surface, the superior support having a posterior edge which is flush with a posterior vertebral face;   an inferior support positioned upon a vertebral surface in facing relation to the superior support such that a posterior edge of the inferior support is flush with a posterior vertebral face;   a member positioned intermediate the superior and inferior supports.   
   
   
       7 . The vertebral implant as described in  claim 6  wherein the member is in the form of a shell with arcuate upper and lower portions. 
   
   
       8 . The vertebral implant as described in  claim 6  wherein the member is a dampening matrix. 
   
   
       9 . The vertebral implant as described in  claim 6  wherein the superior and inferior supports include an overhanging lip portion. 
   
   
       10 . The vertebral implant as described in  claim 6  wherein a spring is positioned between the superior and inferior supports. 
   
   
       11 . A surgical method for replacing damaged fibrocartilage between facing superior and inferior vertebrae in the lumbar region of a patient's spine, the patient having a posterior region, the superior vertebrae including an outer surface, a spinous process and an inferior articular process, the inferior vertebrae including an outer surface, a superior articlular process and pedicals, the method being carried out in a manner that reduces most posterior spinal pathology, the method comprising the following steps:
 accessing the facing superior and inferior vertebrae through the posterior region of the patient;   performing a partial discectomy in order to gain access to the damaged fibrocartilage, the discectomy including removing the spinous process and the inferior articular process of the superior vertebrae and the superior articular process of the inferior vertebrae;   removing the damaged fibrocartilage to create an intervertebral space, the intervertebral space providing access to opposing vertebral surfaces of the superior and inferior vertebrae;   forming superior and inferior channels within the opposing vertebral surfaces, the superior and inferior channels being in facing relation to one another;   providing superior and inferior supports, each of the supports including a plate portion and a lip, with the lip of the inferior support being offset;   inserting the supports within the channels such that the lips of the supports contact the outer vertebral surfaces to thereby limit the insertion of the supports, the offset lip of the inferior support accommodating the pedical of the inferior vertebrae;   inserting a cushioning member in between the superior and inferior supports, the cushioning member functioning to replace the fibrocartilage and absorb forces applied to the intervertebral space.   
   
   
       12 . The method as described in  claim 11  wherein the cushioning member is a coil spring. 
   
   
       13 . The method as described in  claim 11  wherein the cushioning member is a dampening matrix comprising a hydrogel core positioned within a constraining jacket. 
   
   
       14 . The method as described in  claim 11  wherein the cushioning member includes two rounded inserts that are interconnected by a screw. 
   
   
       15 . A surgical method for replacing damaged fibrocartilage between facing superior and inferior vertebrae, the method being carried out in a manner that reduces most posterior spinal pathology, the inferior vertebrae through a posterior region of a patient;
 removing the damaged fibrocartilage to create an intervertebral space;   providing superior and inferior supports, each of the supports including a plate portion;   inserting the superior and inferior supports into the intervertebral space;   positioning a cushioning member in between the superior and inferior supports, the cushioning member functioning to replace the fibrocartilage and absorb forces applied to the intervertebral space.   
   
   
       16 . The method as described in  claim 15  wherein access to the damaged fibrocartilage is gain by performing a partial discectomy. 
   
   
       17 . The method as described in  claim 15  wherein channels are formed within the intervertebral space prior to inserting the supports. 
   
   
       18 . The method as described in  claim 15  wherein the superior and inferior supports include lip portions that limit the insertion of the supports into the intervertebral space. 
   
   
       19 . The method as described in  claim 18  wherein the lip portion of the inferior support is offset. 
   
   
       20 . A surfical method for repairing a vertebral disc comprising:
 posteiorly accessing the damaged vertebral disc;   posteriorly removing the damaged vertebral disc to create an intervertebral space;   providing opposing supports and positioning the supports into the intervertebral space;   positioning a cushioning member in between the opposing supports, the cushioning member functioning to replace the damaged disc.